U.S. patent application number 11/292196 was filed with the patent office on 2006-04-06 for rotary damper, auto part having rotary damper and rotational motion assistant mechanism.
This patent application is currently assigned to Kabushiki Kaisha Somic Ishikawa. Invention is credited to Masanori Itagaki, Hidenori Kanno, Ryota Shimura.
Application Number | 20060070835 11/292196 |
Document ID | / |
Family ID | 27347876 |
Filed Date | 2006-04-06 |
United States Patent
Application |
20060070835 |
Kind Code |
A1 |
Kanno; Hidenori ; et
al. |
April 6, 2006 |
Rotary damper, auto part having rotary damper and rotational motion
assistant mechanism
Abstract
It is an object of the present invention to provide a rotary
damper capable of automatically adjusting an exhibited braking
force in correspondence with variation in load. A fluid chamber 2
into which viscous fluid is charged is formed in a casing 1. A vane
3 is disposed in the fluid chamber 2. The vane 3 is formed with a
fluid passage 5, and is provided with a valve 6. The valve 6
automatically varies a flow rate of the viscous fluid passing
through the fluid passage 5 in correspondence with variation in
load. With this structure, it is possible to automatically adjust
the exhibited braking force in correspondence with variation in
load caused by variation in rotational motion of a subject to be
controlled, and to reduce variation in rotation speed of the
subject to be controlled to an extremely small value.
Inventors: |
Kanno; Hidenori; (Tokyo,
JP) ; Shimura; Ryota; (Tokyo, JP) ; Itagaki;
Masanori; (Tokyo, JP) |
Correspondence
Address: |
EDWARDS & ANGELL, LLP
P.O. BOX 55874
BOSTON
MA
02205
US
|
Assignee: |
Kabushiki Kaisha Somic
Ishikawa
Tokyo
JP
|
Family ID: |
27347876 |
Appl. No.: |
11/292196 |
Filed: |
November 30, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10496855 |
May 27, 2004 |
|
|
|
11292196 |
Nov 30, 2005 |
|
|
|
Current U.S.
Class: |
188/290 |
Current CPC
Class: |
E05Y 2201/21 20130101;
E05Y 2201/256 20130101; F16F 9/512 20130101; E05Y 2201/266
20130101; Y10T 16/625 20150115; F16F 9/34 20130101; F16F 9/145
20130101; F16F 9/20 20130101; B60G 2202/22 20130101 |
Class at
Publication: |
188/290 |
International
Class: |
F16D 57/00 20060101
F16D057/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 23, 2003 |
WO |
PCT/JP02/09888 |
Nov 27, 2001 |
JP |
2001-360466 |
Mar 13, 2002 |
JP |
2002-68778 |
Apr 2, 2002 |
JP |
2002-99500 |
Claims
1-24. (canceled)
25. A rotary damper comprising a fluid chamber which is formed in a
casing and into which viscous fluid is changed, a vane which is
disposed in said fluid chamber, a fluid passage formed in said vane
or in a partition wall which partitions said fluid chamber, and a
valve which automatically varies a flow rate of the viscous fluid
passing through said fluid passage in correspondence with variation
in load, wherein said vane or said partition wall is formed with a
valve hole and said rotary damper further comprises a check valve
which prevents backflow of the viscous fluid which passes through
said valve hole and which allows the viscous fluid to flow only in
one direction.
26. The rotary damper according to claim 25, wherein said valve
hole is formed in said vane or said partition wall formed with said
fluid passage, and said valve and said check valve are composed of
only leaf spring.
27. The rotary damper according to claim 25, wherein said casing
includes a groove capable of supporting one end of a spring member
which biases the rotation of a subject to be controlled in one
direction.
28. The rotary damper according to claim 25, wherein a spring
member is provided in said casing, said spring member biases
rotation of a rotor toward a non-braking force exhibiting
direction, and said vane projects from said rotor.
29. An auto part having a rotary damper according to claim 25.
30. A rotational motion assistant mechanism having a spring member
which biases rotation of a subject to be controlled in one
direction, wherein said rotational motion assistant mechanism
comprises a rotary damper according to claim 25 which delays
rotation of said subject to be controlled in the one direction
against stress of at least said spring member.
Description
TECHNICAL FIELD
[0001] The present invention relates to a rotary damper, and more
particularly, to a rotary damper capable of automatically adjusting
a braking force exhibited in correspondence with change in load.
The invention also relates to an auto part having the rotary
damper, and a rotational motion assistant mechanism.
BACKGROUND ART
[0002] Conventionally, there is a known rotary damper which gives a
predetermined braking force to a subject to be controlled which is
rotated, thereby moderating its rotational motion.
[0003] The rotary damper includes a vane disposed in a fluid
chamber in which viscous fluid is charged. The rotary damper
generates a resistance against the viscous fluid by rocking the
vane. There are a one-way rotary damper in which a check valve is
provided so that the braking force can be exhibited only when the
vane rocks in one direction (e.g., see the following patent
documents 1 and 2), and a two-way rotary damper in which no check
valve is provided so that the braking force can be exhibited
irrespective of the rocking direction of the vane.
[0004] In this kind of rotary damper, the vane rocks and viscous
fluid is pressed, and a resistance is generated when the viscous
fluid moves through a small gap between the vane and a casing, and
the resistance moderates the rotational motion of the subject to be
controlled.
[0005] Therefore, the magnitude of the braking force exhibited by
the rotary damper can be changed by changing a size of a gap or the
like through which the viscous fluid passes when the viscous fluid
moves. That is, if the gap is increased in size, the resistance of
the viscous fluid is reduced and thus, the braking force can be
reduced. If the gap is reduced in size on the contrary, the
resistance of the viscous fluid is increased and thus, the braking
force can be increased.
[0006] In the conventional rotary damper, the size of the gap
through which the viscous fluid passes when the viscous fluid moves
is usually constant. Thus, the exhibited braking force is also
constant.
[0007] In a rotary damper in which the exhibited braking force is
constant, when a load is small, the braking force becomes large
relatively and when the load is great, the braking force becomes
small relatively. Therefore, when the load is varied, the rotation
speed of the subject to be controlled is largely varied.
[0008] Therefore, if such a rotary damper is applied to the subject
to be controlled which has an accommodating section for
accommodating an article such as an inner lid of a console box of
an automobile or a glove box disposed in an opening formed in an
instrument panel of an automobile, and in which the accommodating
section is turned, a rotational moment of the subject to be
controlled is small when no article is accommodated, and since a
load applied to the rotary damper is small, the rotational motion
of the subject to be controlled becomes extremely slow. On the
contrary, when an article is accommodated, the rotational moment of
the subject to be controlled is great and the load applied to the
rotary damper becomes great and thus, the rotational motion of the
subject to be controlled adversely becomes fast.
[0009] There is also a known rotary damper in which a size of a gap
or the like through which viscous fluid passes when the viscous
fluid moves is changed by operating the gap from outside, and the
exhibited braking force can be adjusted (e.g., see the following
patent documents 3 and 4).
[0010] In such a rotary damper, however, although the braking force
can be adjusted, this adjustment is carried out based on a premise
that a load to be applied to the rotary damper is constant after
the adjustment. Thus, even if the braking force exhibited in
accordance with a subject to be controlled is adjusted at initial
stage of installation of the rotary damper, if a weight of the
subject to be controlled is changed thereafter and a load to be
applied to the rotary damper is changed, it is not possible to
rotate the subject to be controlled at desired rotation speed
unless the braking force is again adjusted.
[0011] Further, such a rotary damper must be operated from outside
to adjust the braking force. Thus, if the rotational moment of the
subject to be controlled is frequently changed and its changing
amount is not constant like the inner lid of the console box or the
glove box, this rotary damper is not suitable. That is, if the
rotary damper is applied to such a subject to be controlled,
whenever the rotational moment is changed as an article is loaded
and unloaded, the braking force of the rotary damper must be
adjusted again by predicting the changing amount of the rotational
moment and operating the rotary damper from outside. Thus, it is
difficult to appropriately adjust the braking force, and its
operation is extremely troublesome and inconvenient.
[0012] In the conventional one-way rotary damper, a valve which
realizes the one way rotary damper is formed as an independent
member and then, the valve is assembled as one constituent part of
the rotary damper. Thus, the number of parts is increased, a
procedure for assembling the valve is necessary, and this increases
the producing cost.
[0013] The rotary damper can moderate the rotational motion of the
subject to be controlled by its shock absorbing effect. Therefore,
when the rotary damper is applied to a reclining seat of an
automobile, it is possible to moderate the forward rotational
motion of a seat back against a biasing force of a spring member of
a reclining mechanism which biases the seat back of the seat
forward (see the following patent document 5 for example).
[0014] In the conventional rotary damper, however, the braking
force can not be adjusted in accordance with the change in load.
Therefore, in a reclining seat from which a head rest can be
detached, the rotational moment of the seat back is changed between
a case in which the head rest is attached and a case in which the
head rest is detached. Thus, the rotation speed of the seat back is
largely changed depending upon presence and absence of the head
rest.
[0015] As other auto part, it is proposed to use the rotary damper
also for an arm rest (see the following patent document 6 for
example). However, in the arm rest having an accommodating section
for articles, the rotational moment of the arm rest is changed
depending upon a case in which the article is accommodated and a
case in which no article is accommodated. Thus, in a rotary damper
which can not adjust the braking force in accordance with the
change in load, the rotational moment of the arm rest is changed,
and its rotation speed is largely changed.
[0016] As a rotational motion assistant mechanism having a spring
member which biases a subject to be controlled in one direction,
there is a known mechanism which can adjust a biasing force of a
spring member applied to the subject to be controlled by utilizing
a fact that a stress of the spring member is changed by changing a
position of a fulcrum of the spring member (see the following
patent document 7 for example).
[0017] According to such a rotational motion assistant mechanism,
however, since the biasing force of the spring member applied to
the subject to be controlled is adjusted, a user must somehow
operate the mechanism to change the position of the fulcrum of the
spring member, and such an operation is troublesome and
inconvenient.
[0018] The followings are conventional arts related the present
invention:
[0019] Patent Document 1: Japanese Patent Application Laid-open No.
H7-301272
[0020] Patent Document 2: Japanese Patent Application Laid-open No.
2002-81482
[0021] Patent Document 3: Japanese Patent Application Laid-open No.
H7-197970
[0022] Patent Document 4: Japanese Patent Application Laid-open No.
H7-301272
[0023] Patent Document 5: Japanese Patent Application Laid-open No.
H8-38290
[0024] Patent Document 6: Japanese Patent Application Laid-open No.
2002-67767
[0025] Patent Document 7: Japanese Patent Application Laid-open No.
2001-169840
[0026] The present invention has been accomplished in view of the
above-described circumstances, and it is an object of the invention
to provide a rotary damper capable of automatically adjusting a
braking force exhibited in correspondence with change in load. It
is another object of the invention to provide an auto part in which
variation in rotation speed is small even if the rotational moment
is changed. It is another object of the invention to provide a
rotational motion assistant mechanism capable of automatically
adjusting a biasing force of a spring member applied to a subject
to be controlled in correspondence with change in rotation moment
of the subject to be controlled.
DISCLOSURE OF THE INVENTION
[0027] To solve the above problems, the present invention provides
the following rotary damper, auto part and rotational motion
assistant mechanism.
[0028] 1. A rotary damper comprising a fluid chamber which is
formed in a casing and into which viscous fluid is charged, a vane
which is disposed in said fluid chamber, a fluid passage formed in
said vane or in a partition wall which partitions said fluid
chamber, and a valve which automatically varies a flow rate of the
viscous fluid passing through said fluid passage in correspondence
with variation in load.
[0029] 2. The rotary damper according to claim 1, wherein said
valve automatically varies a flow rate of the viscous fluid passing
through said fluid passage in correspondence with variation in load
only when said vane or said partition wall rocks in one
direction.
[0030] 3. The rotary damper according to claim 1, wherein said
valve automatically varies a flow rate of the viscous fluid passing
through said fluid passage in correspondence with variation in load
irrespective of a rocking direction of said vane or said partition
wall.
[0031] 4. The rotary damper according to any one of claims 1 to 3,
wherein said vane or said partition wall is formed with a valve
hole through which the viscous fluid can pass, and said rotary
damper further comprises a check valve which prevents backflow of
the viscous fluid which passes through said valve hole and which
allows the viscous fluid to flow only in one direction.
[0032] 5. The rotary damper according to claim 4, wherein said vane
or said partition wall which is formed with said fluid passage is
formed with said valve hole, and said valve and said check valve
comprise one leaf spring.
[0033] 6. The rotary damper according to any one of claims 1 to 5,
wherein said valve comprises a leaf spring including a to-be
supported portion which is supported by said vane or said partition
wall, and a flow rate-adjusting portion which is formed at its one
surface with a pressure-receiving surface, and wherein if said
pressure-receiving surface receives a pressure of the viscous
fluid, said flow rate-adjusting portion is deformed to adjust the
flow rate of the viscous fluid which passes through said fluid
passage.
[0034] 7. The rotary damper according to claim 6, wherein said flow
rate-adjusting portion constituting said valve is formed at its one
surface with a pressure-receiving surface comprising two or more
inclined surfaces having different inclining angles.
[0035] 8. The rotary damper according to claim 6, wherein said flow
rate-adjusting portion constituting said valve is bent such that
one surface of said flow rate-adjusting portion on which said
pressure-receiving surface is formed projects.
[0036] 9. The rotary damper according to any one of claims 1 to 4,
wherein said valve is integrally formed on said vane or said
partition wall.
[0037] 10. A rotary damper comprising a rotor provided in a casing,
a fluid chamber which is partitioned by a partition wall provided
between said rotor and said casing and into which viscous fluid is
charged, an engaging portion projecting from said rotor and
disposed in said fluid chamber, a one-way valve body capable of
engaging with said engaging portion with a play therebetween, a
fluid passage formed between said valve body and said engaging
portion, and a resilient member provided in said fluid passage for
biasing said valve body in one direction, wherein said resilient
member is deformed when said valve body receives a pressure of the
viscous fluid and moves, and said valve body reduces a flow rate of
the viscous fluid passing through said fluid passage in accordance
with a deforming degree of said resilient member.
[0038] 11. The rotary damper according to claim 10, wherein at
least one of said engaging portion and said valve body is formed
with a backflow groove which forms said fluid passage.
[0039] 12. The rotary damper according to claim 10 or 11, wherein
said valve body is formed into a substantially T-shape having a
projection which engages with said engaging portion with a play
therebetween, and an arc portion having a predetermined width, said
arc portion slides with respect to an inner peripheral surface of
said casing when said casing or said rotor rotates.
[0040] 13. The rotary damper according to any one of claims 10 to
12, wherein said resilient member comprises a leaf spring which is
curved such that its one surface projects.
[0041] 14. The rotary damper according to claim 13, wherein said
resilient member includes a notch or a hole which penetrates said
resilient member in its thickness direction.
[0042] 15. The rotary damper according to any one of claims 1 to
14, wherein said casing includes a groove capable of supporting one
end of a spring member which biases the rotation of a subject to be
controlled in one direction.
[0043] 16. The rotary damper according to any one of claims 1 to
15, wherein said vane or said engaging portion projects from a
rotor, and said rotary damper further comprises a click mechanism
which is provided in said casing and which stops rotation of said
rotor at a predetermined rotation angle.
[0044] 17. The rotary damper according to claim 16, wherein said
click mechanism comprises a spring member provided in said casing,
and a rolling member which abuts against a surface formed in said
casing and having a projection when said rolling member is biased
by said spring member, and said rolling member rolls along said
abutment surface when said rotor rotates.
[0045] 18. The rotary damper according to claim 17, wherein the
projection constituting said abutment surface comprises a hard
member having a predetermined height.
[0046] 19. The rotary damper according to claim 18, wherein said
hard member can rotate.
[0047] 20. The rotary damper according to claim 2 or 10, wherein a
spring member is provided in said casing, said spring member biases
rotation of a rotor toward a non-braking force exhibiting
direction, and said vane or said engaging portion projects from
said rotor.
[0048] 21. The rotary damper according to any one of claims 1 to
20, wherein said rotor from which said vane or said engaging
portion projects, said rotor is hollow, and an inner shaft is
provided in the hollow portion.
[0049] 22. The rotary damper according to claim 21, wherein said
inner shaft engages with said rotor, said inner shaft rotates
together with said rotor, said inner shaft is cut at its
intermediate portion, and a coil spring is disposed in the cut
portion.
[0050] 23. An auto part having a rotary damper according to any one
of claims 1 to 22.
[0051] 24. A rotational motion assistant mechanism having a spring
member which biases rotation of a subject to be controlled in one
direction, wherein said rotational motion assistant mechanism
comprises a rotary damper according to any one of claims 1 to 22
which delays rotation of said subject to be controlled in the one
direction against stress of at least said spring member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0052] FIG. 1 shows an internal structure of a rotary damper
according to an embodiment 1.
[0053] FIG. 2 is a sectional view taken along A-A line in FIG.
1.
[0054] FIG. 3 is a sectional view taken along B-B line in FIG.
1.
[0055] FIG. 4 show a valve employed in the embodiment 1, wherein
(a) is a front view and (b) is a sectional view taken along A-A
line in (a).
[0056] FIG. 5 are diagrams for explaining the operation of the
valve employed in the embodiment 1.
[0057] FIG. 6 is a graph showing a result of a comparison
experiment between the rotary damper of the embodiment 1 and a
rotary damper of a comparative example.
[0058] FIG. 7 shows an internal structure of a rotary damper
according to an embodiment 2.
[0059] FIG. 8 is a sectional view taken along A-A line in FIG.
7.
[0060] FIG. 9 is a sectional view taken along B-B line in FIG.
7.
[0061] FIG. 10 show a valve employed in the embodiment 2, wherein
(a) is a front view and (b) is a right side view.
[0062] FIG. 11 are diagrams for explaining the operation of the
valve employed in the embodiment 2, wherein (a) and (b) are
sectional views taken along A-A line in FIG. 9.
[0063] FIG. 12 shows an internal structure of a rotary damper
according to an embodiment 3.
[0064] FIG. 13 is a sectional view taken along A-A line in FIG.
12.
[0065] FIG. 14 is a sectional view taken along B-B line in FIG.
12.
[0066] FIG. 15 is a sectional view taken along C-C line in FIG.
12.
[0067] FIG. 16 show a valve employed in the embodiment 3.
[0068] FIG. 17 are diagrams for explaining a click mechanism
employed in the embodiment 3.
[0069] FIG. 18 shows an internal structure of a rotary damper
according to an embodiment 4.
[0070] FIG. 19 are diagrams for explaining a structure and an
effect of a valve and a check valve employed in the embodiment
4.
[0071] FIG. 20 shows an internal structure of a rotary damper
according to an embodiment 5.
[0072] FIG. 21 shows an internal structure of a rotary damper
according to an embodiment 6.
[0073] FIG. 22 is a sectional view taken along A-A line in FIG.
21.
[0074] FIG. 23 is a sectional view taken along B-B line in FIG.
21.
[0075] FIG. 24 shows structures of a vane and a valve employed in
the embodiment 6.
[0076] FIG. 25 shows structures of other vane and valve.
[0077] FIG. 26 shows an internal structure of a rotary damper
according to an embodiment 7.
[0078] FIG. 27 shows an internal structure of a rotary damper
according to an embodiment 8.
[0079] FIG. 28 shows an internal structure of a rotary damper
according to an embodiment 9.
[0080] FIG. 29 show a valve body employed in the embodiment 9,
wherein (a) is a plan view, (b) is a front view and (c) is a
sectional view taken along A-A line in (b).
[0081] FIG. 30 show a resilient member employed in the embodiment
9, wherein (a) is a front view and (b) is a right side view.
[0082] FIG. 31 are diagram for explaining effects of a valve body
and the resilient member employed in the embodiment 9.
[0083] FIG. 32 are diagram for explaining effects of the valve body
and the resilient member employed in the embodiment 9.
[0084] FIG. 33 shows a glove box according to an embodiment of the
present invention.
[0085] FIG. 34 is a sectional view taken along A-A line in FIG.
33.
[0086] FIG. 35 shows a console box of the embodiment of the
invention.
[0087] FIG. 36 shows the console box of the embodiment of the
invention.
[0088] FIG. 37 shows the console box of the embodiment of the
invention.
[0089] FIG. 38 is a schematic right side view showing a reclining
seat of the embodiment of the invention.
[0090] FIG. 39 is a schematic left side view showing a reclining
seat of the embodiment of the invention.
[0091] FIG. 40 is a diagram for explaining a mounting method of the
rotary damper employed for the reclining seat of the embodiment of
the invention.
[0092] FIG. 41 is a right side view for showing an essential
portion of an arm rest of the embodiment of the invention.
[0093] FIG. 42 is a sectional view taken along A-A line in FIG.
41.
[0094] FIG. 43 is a front view showing a hoisting and lowering case
having a rotational motion assistant mechanism of the embodiment of
the invention.
[0095] FIG. 44 is a left side view showing the hoisting and
lowering case having the rotational motion assistant mechanism of
the embodiment of the invention.
[0096] FIG. 45 is a diagram for explaining en effect of the
rotational motion assistant mechanism of the embodiment of the
invention.
[0097] In the drawings, a symbol 1 represents a casing, a symbol 2
represents a fluid chamber, a symbol 3 represents vane, a symbol 4
represents a partition wall, a symbol 5 represents a fluid passage,
a symbol 6 represents a valve and a symbol 7 represents a
rotor.
BEST MODE FOR CARRYING OUT THE INVENTION
[0098] A rotary damper according to the present invention will be
explained in detail based on embodiments illustrated in the
drawings, but it should be noted that the scope of the invention is
not limited by the embodiments.
Embodiment 1
[0099] FIGS. 1 to 3 show an internal structure of a rotary damper
D1 according to the embodiment 1. As shown in FIGS. 1 to 3, a
casing 1 of the rotary damper D1 comprises a cylindrical portion 1b
whose one end is opened and other end is closed with a bottom wall
1a, and a closing portion 1c which closes an opening of the
cylindrical portion 1b. An outer peripheral surface of the
cylindrical portion 1b is formed with a groove 1d. The groove 1d
can support one end of a spring member which biases a subject to be
controlled in one direction. The subject to be controlled rotates.
The cylindrical portion 1b is provided with a partition wall 4
which projects from an inner peripheral surface of the cylindrical
portion 1b in its axial direction. A tip end surface of the
partition wall 4 is curved such that an outer peripheral surface of
the rotor 7 slides on the tip end surface.
[0100] The rotor 7 is provided in the casing 1. That is, the rotor
7 is provided in the casing 1 along an axis of the casing 1. With
this structure, a space partitioned by the partition wall 4 is
formed between the rotor 7 and the casing 1. This space serves as a
fluid chamber 2. Viscous fluid such as silicon oil is charged into
the fluid chamber 2.
[0101] Here, the rotor 7 includes a hollow portion 7a formed such
as to penetrate the rotor 7 along its axis. A support shaft which
serves as a rotation center of the subject to be controlled is
inserted into the hollow portion 7a. By forming the hollow portion
7a in the rotor 7 in this manner, the rotor 7 can directly be
connected to the support shaft. Therefore, the installation space
of the rotary damper D1 can be reduced.
[0102] The vane 3 is integrally formed on the rotor 7 such as to
project from the outer peripheral surface of the rotor 7 toward an
inner peripheral surface of the cylindrical portion 1b. The vane 3
has such a length along its axial direction that when the rotor 7
rotates in the casing 1, one end surface of the vane 3 slides on
the closing portion 1c and the other end surface slides on the
bottom wall 1a of the cylindrical portion 1b. The vane 3 has such a
radial length that the tip end surface slides on the inner
peripheral surface of the cylindrical portion 1b. This vane 3 is
disposed in the fluid chamber 2. With this structure, the one fluid
chamber 2 is partitioned into two chambers ("first chamber 2a" and
"second chamber 2b", hereinafter).
[0103] The fluid passage 5 is formed in the vane 3 along a
direction substantially in parallel to the axis of the rotor 7 such
that one of the openings of the fluid passage 5 is in communication
with the first chamber 2a and the other opening is in communication
with the second chamber 2b (see FIG. 3). If the fluid passage 5 is
provided in the direction substantially in parallel to the axis of
the rotor 7 in this manner, the shape of a mold for forming the
rotor 7 can be simplified and thus, the producing cost of the mold
can be suppressed.
[0104] The valve 6 automatically adjusts a flow rate of the viscous
fluid passing through the fluid passage 5 in accordance with
variation in load. That is, the valve 6 reduces the flow rate of
the viscous fluid passing through the fluid passage 5 as the load
is increased, and increases the flow rate of the viscous fluid as
the load is reduced without operating from outside. In this
embodiment, in order to achieve this function with a simple
structure, the following valve 6 is employed.
[0105] That is, as shown in FIGS. 3 and 4, the valve 6 is a leaf
spring comprising a to-be supported portion 6c supported by the
vane 3, and a flow rate-adjusting portion 6d. A pressure-receiving
surface is formed on one surface of the flow rate-adjusting portion
6d, and if the pressure-receiving surface receives a pressure of
the viscous fluid, the pressure-receiving surface is deformed to
adjust the flow rate of the viscous fluid passing through the fluid
passage 5.
[0106] The to-be supported portion 6c is fixed to the vane 3. The
flow rate-adjusting portion 6d is formed at its one surface with
two inclined surfaces 6a and 6b whose inclining angles are
different from each other. The to be supported portion 6c is
provided such that when no load is applied, the fluid passage 5 is
not closed (see FIG. 3). In this manner, the flow rate-adjusting
portion 6d is formed at its one surface with the pressure-receiving
surface comprising the two inclined surfaces 6a and 6b having the
different inclining angles. With this structure, the surface of the
flow rate-adjusting portion 6d receiving the pressure of the
viscous fluid is formed with the bent portion. Therefore, it is
possible to cover a wider range of variation of the load as
compared with a flow rate-adjusting portion having only one
inclined surface.
[0107] The rotary damper D1 having the above-described structure
functions as follows. That is, if the rotor 7 connected to the
subject to be controlled through the support shaft is rotated in
the counterclockwise direction in the casing 1 as the subject to be
controlled is rotated in FIG. 1, the vane 3 pushes the viscous
fluid in the second chamber 2b. With this, the viscous fluid in the
second chamber 2b flows into the fluid passage 5. As shown in FIG.
3 and 5(a), the valve 6 located on the one of the openings of the
fluid passage 5 is provided such that the flow rate-adjusting
portion 6d does not close the fluid passage 5. Therefore, the
viscous fluid which flowed into the fluid passage 5 from the second
chamber 2b passes through the fluid passage 5 and flows into the
first chamber 2a without being prevented from moving by the valve 6
almost at all. Thus, the resistance of the viscous fluid is
extremely small. Therefore, the rotary damper D1 does not exhibit a
braking force which affects the rotational motion of the subject to
be controlled.
[0108] If the rotor 7 rotates in the clockwise direction in the
casing 1 in FIG. 1 as the subject to be controlled rotates in the
opposite direction on the contrary, the vane 3 pushes the viscous
fluid in the first chamber 2a. With this, the pressure-receiving
surfaces 6a and 6b formed on the flow rate-adjusting portion 6d of
the valve 6 receive the pressure of the viscous fluid.
[0109] At that time, when the rotational moment of the subject to
be controlled is small and the load applied to the rotary damper D1
is small, a force of the vane 3 pushing the viscous fluid in the
first chamber 2a is small and a pressure of the viscous fluid
generated by this is also small. Therefore, the flow rate-adjusting
portion 6d of the valve 6 is only slightly deformed in a direction
closing the fluid passage 5 as compared with a case in which the
flow rate-adjusting portion 6d does not receive the pressure of the
viscous fluid (see FIG. 5(a)).
[0110] On the other hand, when the rotational moment of the subject
to be controlled is great and the load applied to the rotary damper
D1 is great, the force of the vane 3 pushing the viscous fluid in
the first chamber 2a is also great, and the pressure of the viscous
fluid generated by this is also high. Therefore, the flow
rate-adjusting portion 6d of the valve 6 is deformed such as to
close a portion of the opening of the fluid passage 5 closer to the
first chamber 2a by a portion of the flow rate-adjusting portion 6d
having one (6a) of the two inclined surfaces 6a and 6b having the
smaller inclining angle as shown in FIG. 5(b).
[0111] When a load equal to or greater than a predetermined value
is applied to the rotary damper D1, not only the portion of the
flow rate-adjusting portion 6d of the valve 6 having the inclined
surface 6a but also a portion of the flow rate-adjusting portion 6d
having the inclined surface 6b having the larger inclining angle
are largely deformed, and the flow rate-adjusting portion 6d
completely closes the fluid passage 5 as shown in FIG. 5(c).
[0112] By employing, in the rotary damper D1, the valve 6 having
the flow rate-adjusting portion 6d whose deforming degree is
changed in accordance with variation in load, a gap between the
flow rate-adjusting portion 6d of the valve 6 and the opening of
the fluid passage 5 closer to the first chamber 2a can be made
small and the opening can be closed gradually as the load is
increased. Therefore, it is possible to limit the flow rate of the
viscous fluid moving from the first chamber 2a to the second
chamber 2b through the fluid passage 5 such that the flow rate is
gradually reduced.
[0113] Thus, according to the rotary damper D1, it is possible to
automatically adjust the magnitude of the braking force which is
exhibited in accordance with variation in load such that when the
load is small, the braking force to be exhibited is small, and when
the load is great, the braking force to be exhibited becomes great
without operating the rotary damper from outside. As a result,
according to the rotary damper D1, the variation in rotation speed
can be reduced to an extremely small value even if the rotational
moment of the subject to be controlled is varied.
[0114] When the flow rate-adjusting portion 6d of the valve 6
completely closes the fluid passage 5, the viscous fluid can not
move from the first chamber 2a to the second chamber 2b through the
fluid passage 5, and the viscous fluid can only move between the
chambers 2a and 2b through a slight gap formed between the casing 1
and the vane 3. Thus, the rotary damper D1 exhibits greater braking
force.
[0115] In order to confirm the characteristics of the rotary
dampers D1 of the embodiment, experiments for comparing the rotary
damper D1 of the embodiment with a comparative example were carried
out. The rotary damper of the comparative example had a normal
check valve as a valve which limited the movement of viscous fluid,
i.e., a valve which prevented the viscous fluid from flowing
reversely and which allowed the viscous fluid to flow only in one
direction. Other structures of the rotary damper of the comparative
example are the same as those of the rotary damper D1 of the
embodiment.
[0116] In the experiments, a plate body whose one end was pivotally
supported and other end was free was used as the subject to be
controlled, and a support shaft which was a rotation center of the
subject to be controlled was connected to the rotary damper D1 of
the embodiment. The comparative example had the same condition.
Operation time required from the instant when the free end of the
subject to be controlled fell from an angle position of 60.degree.
to the instant when the free end reached an angle position of
0.degree. was measured. The rotational motion of the subject to be
controlled was changed by adding a weight having different weight
to the subject to be controlled. Table 1 shows a result of the
experiments, and the average operation time is shown in FIG. 6 as a
graph. TABLE-US-00001 TABLE 1 Rotational Operation time (second)
moment First Second Third Fourth (N m) time time time time Average
Embodiment 0.5 7.22 7.40 7.25 -- 7.29 Comparative 0.5 21.15 22.78
25.81 -- 23.25 example Embodiment 1.0 4.75 4.78 4.78 -- 4.77
Comparative 1.0 15.18 15.29 14.66 14.99 15.03 example Embodiment
1.5 3.44 3.50 3.03 3.06 3.26 Comparative 1.5 7.72 7.50 7.46 -- 7.56
example Embodiment 2.0 2.34 2.34 2.25 -- 2.31 Comparative 2.0 4.29
4.19 4.19 -- 4.22 example Embodiment 2.5 1.78 1.75 1.79 -- 1.77
Comparative 2.5 2.44 2.35 2.38 -- 2.39 example Embodiment 3.0 1.25
1.28 1.31 1.28 1.28 Comparative 3.0 1.28 1.31 1.31 -- 1.30
example
[0117] From the results shown in Table 1 and FIG. 6, it can be
found that if the rotational moment of the subject to be controlled
controlled by the rotary damper of the comparative example is
changed, its operation time is also changed largely. On the other
hand, in the case of the subject to be controlled controlled by the
rotary damper D1 of the present embodiment, it can be found that
even if the rotational moment is changed, the variation in
operation time thereof is extremely small. That is, differences of
the average operation time when the rotational moment is 0.5Nm and
3.0Nm are compared, the difference of the operation time of the
subject to be controlled controlled by the rotary damper D1 of the
present embodiment is 6.01 seconds and the variation is small, but
the difference of the operation time of the subject to be
controlled controlled by the rotary damper of the comparative
example is 21.95 seconds and the variation is extremely large.
Further, differences of the average operation time when the
rotational moment is 1.0Nm and 3.0Nm are compared with each other,
the difference of the operation time of the subject to be
controlled controlled by the rotary damper D1 of the present
embodiment is only 3.49 seconds and the variation is extremely
small, but the difference of the operation time of the subject to
be controlled controlled by the rotary damper of the comparative
example is 13.73 seconds and the variation is large. From the
results, it was confirmed that according to the rotary damper D1 of
the present embodiment, even if the rotational moment of the
subject to be controlled was changed, the braking force exhibited
in correspondence with the variation in load was automatically
adjusted, and the variation of the rotation speed of the subject to
be controlled could be reduced to an extremely small value.
Embodiment 2
[0118] In a rotary damper D2 of this embodiment, as shown in FIGS.
7, 9 and 11, the fluid passage 5 comprises large hole portions 5a
which pass through the fluid passage 5 in the thickness direction
of the vane 3 and which are in communication with each other, and a
small hole portion 5b which is smaller than the large hole portion
5a in diameter. As shown in FIG. 10, the valve 6 comprises a leaf
spring having to-be supported portions 6e and 6f and a flow
rate-adjusting portion 6g.
[0119] As shown in FIG. 10, in the valve 6, in order to secure a
passage for the viscous fluid, a width of a central portion of the
flow rate-adjusting portion 6g located between the to-be supported
portions (opposite ends) 6e and 6f is smaller than widths of the
to-be supported portions (opposite ends) 6e and 6f. The to-be
supported portions (opposite ends) 6e and 6f of the valve 6 are
folded back into substantially U-shape as viewed from side so that
the inner surface of the casing 1 (inner surfaces of the bottom
wall 1a and inner surface of the closing portion 1c) is not damaged
by the to-be supported portions (opposite ends) 6e and 6f. The flow
rate-adjusting portion 6d is bent such that one surface thereof
projects.
[0120] As shown in FIGS. 7, 9 and 11, the valve 6 is located on a
boundary portion between the large hole portion 5a and the small
hole portion 5b constituting the fluid passage 5, and is disposed
in a groove 5c formed along a direction which is substantially
perpendicular to the thickness direction of the vane 3.
[0121] Like the embodiment 1, this valve 6 is provided such that
when no load is applied, the fluid passage 6 is not closed by the
flow rate-adjusting portion 6g. That is, when no load is applied to
the rotary damper D2, as shown in FIG. 11(a), the to-be supported
portions (opposite ends) 6e and 6f of the valve 6 abut against the
vane 3 in the groove 5c, and even when they are supported by the
vane 3, the flow rate-adjusting portion 6g maintains such a shape
that the flow rate-adjusting portion 6g is bent such that its one
surface is bent. Therefore, a gap through which the viscous fluid
can pass is formed between the flow rate-adjusting portion 6g and
an opening of the small hole portion 5b closer to the large hole
portion 5a which constitutes the fluid passage 5 (simply "opening
of the small hole portion 5b", hereinafter).
[0122] In the rotary damper D2 having the above-described
structure, if the rotor 7 is rotated in the counterclockwise
direction in FIG. 7 in the casing 1, the vane 3 pushes the viscous
fluid in the first chamber 2a. With this the flow rate-adjusting
portion 6g of the valve 6 receives the pressure of the viscous
fluid flowing into the large hole portion 5a of the fluid passage
5, and the flow rate-adjusting portion 6g is deformed in a
direction closing the opening of the small hole portion 5b.
[0123] At that time, when the load applied to the rotary damper D2
is small, a force of the vane 3 pressing the viscous fluid in the
first chamber 2a is also small and the pressure of the viscous
fluid generated by this is also small. Therefore, the flow
rate-adjusting portion 6g of the valve 6 is only deformed slightly
in a direction closing the opening of the small hole portion 5b as
compared with a case in which the flow rate-adjusting portion 6g
does not receive the pressure of the viscous fluid (see FIG.
11(a)).
[0124] On the other hand, when the load applied to the rotary
damper D2 is large, the force of the vane 3 pressing the viscous
fluid in the first chamber 2a is also strong and the pressure of
the viscous fluid generated by this is also great. Therefore, the
flow rate-adjusting portion 6g of the valve 6 is largely deformed
in the direction closing the opening of the small hole portion 5a
as compared with a case in which the load is small.
[0125] When a load equal to or greater than a predetermined value
is applied, the flow rate-adjusting portion 6g of the valve 6 is
more largely deformed and completely closes the opening of the
small hole portion 5b as shown in FIG. 11(b).
[0126] According to the rotary damper D2, like the embodiment 1,
the valve 6 having the flow rate-adjusting portion 6g whose
deforming degree is varied in accordance with the variation in load
is employed. Therefore, as the load becomes greater, the gap
between the flow rate-adjusting portion 6g of the valve 6 and the
opening of the small hole portion 5b constituting the fluid passage
5 becomes smaller and the opening can be closed gradually. Thus, it
is possible to limit the flow rate of the viscous fluid which moves
from the first chamber 2a to the second chamber 2b through the
fluid passage 5 such that the flow rate is gradually reduced.
[0127] Thus, according to the rotary damper D2, the magnitude of
the braking force exhibited in accordance with the variation in
load can automatically be adjusted without operating the rotary
damper from outside such that when the load is small, the braking
force to be exhibited is small, and when the load is great, the
braking force to be exhibited becomes great. As a result, like the
embodiment 1, even if the rotational moment of the subject to be
controlled is varied, the variation in rotation speed can be
reduced to an extremely small value.
[0128] When the flow rate-adjusting portion 6g of the valve 6
completely closes the small hole portion 5b of the fluid passage 5,
the viscous fluid can not pass through the fluid passage 5, and the
viscous fluid can move between the first chamber 2a and the second
chamber 2b only through the small gap formed between the casing 1
and the vane 3. Thus, the rotary damper D2 exhibits greater braking
force.
[0129] When the rotor 7 is rotated in the clockwise direction in
FIG. 7 in the casing 1 on the contrary, the vane 3 pushes the
viscous fluid in the second chamber 2b. With this, the viscous
fluid in the second chamber 2b flows into the small hole portion 5b
of the fluid passage 5. At that time, since the flow rate-adjusting
portion 6g of the valve 6 is provided such that it does not close
the opening of the small hole portion 5b as shown in FIG. 11(a),
the viscous fluid which flowed into the small hole portion 5b flows
into the large hole portion 5a and into the first chamber 2a
without being prevented from moving by the valve 6 almost at all.
Thus, the resistance of the viscous fluid is extremely small.
Therefore, the rotary damper D2 does not exhibit a braking force
which can affect the rotational motion of the subject to be
controlled.
Embodiment 3
[0130] FIGS. 12 to 15 show an internal structure of a rotary damper
D3 of this embodiment. As shown in these drawings, the casing 1 of
the rotary damper D3 comprises a cylindrical portion 1e having a
substantially circular cross section, and first and second closing
portions 1f and 1g which close opposite ends of the cylindrical
portion 1e. The first closing portion 1f which closes one end of
the cylindrical portion 1e is formed at its inner surface with a
recess having a substantially arc cross section. A hard member 12c
which will be described later is disposed in the recess. By
disposing the hard member 12c in the recess, a surface having a
projection against which a later-described rolling member 12b is
formed (see FIGS. 14 and 17). Instead of forming the recess in the
inner surface of the first closing portion 1f, this portion may be
protruded and the inner surface itself of the first closing portion
1f may be formed with the projection. The first and second closing
portions 1f and 1g have shaft insertion holes 1h and 1i through
which the rotor 7 is inserted. The rotor 7 functions as a rotation
shaft. The first and second closing portions 1f and 1g are mounted
by swaging the cylindrical portion 1e.
[0131] The opposite ends of the rotor 7 are supported by the shaft
insertion holes 1h and 1i respectively formed in the first and
second closing portions 1f and 1g so that the rotor 7 is provided
along an axis of the casing 1. The rotor 7 is hollow, and an inner
shaft 13 is disposed in the hollow portion. The inner shaft 13 has
such a shape that the inner shaft 13 engages with the rotor 7 and
can rotate together with the rotor 7, and the inner shaft 13 is cut
at its intermediate portion, and a coil spring 14 is disposed in
the cut portion. With this structure, the inner shaft 13 can expand
and shrink using the resilience of the coil spring 14 and thus, the
inner shaft 13 can easily be mounted on the subject to be
controlled.
[0132] When the rotary damper D3 of this embodiment is applied as a
double lid type opening/closing supporting mechanism comprising an
outer lid and an inner lid, a base end of the outer lid is
rotatably connected to the inner shaft 13, a base end of the inner
lid is engaged and mounted such that the inner shaft 13 is rotated
by rotating the inner lid. With this structure, the outer lid and
the inner lid can opened and closed independently. When the inner
shaft 13 is rotatably provided in the hollow portion of the rotor 7
unlike this embodiment, the base end of the inner lid is connected
to the rotor 7, and the base end of the outer lid is connected to
the inner shaft 13. With this structure, the outer lid and the
inner lid can opened and closed independently.
[0133] As shown in FIG. 15, the partition walls 4 are provided such
as to project from the inner peripheral surface of the cylindrical
portion 1e which constitutes the casing 1 and such as to be opposed
to each other. Each of tip end surfaces of the partition walls 4
has a substantially arc cross section so that the tip end surface
slides on the outer peripheral surface of the rotor 7.
[0134] As shown in FIG. 15, the vane 3 projects from the rotor 7
and is disposed such as to partition the fluid chamber 2 into the
first chamber 2a and the second chamber 2b by means of the
partition walls 4. In this embodiment, two vanes 3 are disposed
such as to be opposed to each other with the rotor 7 interposed
therebetween such that each of the two fluid chambers 2 formed in
the casing 1 are partitioned into the first chamber 2a and the
second chamber 2b by the two partition walls 4. As shown in FIG.
12, each vane 3 is formed with the fluid passage 5 which passes
through the vane 3 in its thickness direction.
[0135] Viscous fluid such as silicon oil is charged into the fluid
chamber 2. A seal member such as an O-ring is disposed on a
predetermined position in the casing 1 to prevent the viscous fluid
from leaking outside.
[0136] The valve 6 changes the flow rate of the viscous fluid
moving from the first chamber 2a to the second chamber 2b through
the fluid passage 5 in accordance with variation in load. That is,
as the load becomes greater, the valve 6 reduces the flow rate of
the viscous fluid passing through the fluid passage 5, and as the
load becomes smaller, the valve 6 increases the flow rate. A
structure of the valve. 6 is not limited only if the valve 6 can
exhibit this function. In order to achieve this function with a
simple structure, the following structure is employed for the valve
6.
[0137] That is, as shown in FIGS. 12, 15 and 16, the valve 6
comprises a leaf spring having the to-be supported portion 6c and
the flow rate-adjusting portion 6d. The to-be supported portion 6c
located at a substantially central portion of the valve 6 is fixed
to the vane 3 using a push nut 15. The flow rate-adjusting portion
6d is formed into such a shape that it is inclined from the to-be
supported portion 6c so that the flow rate-adjusting portion 6d
does not close the fluid passage 5 when no load is applied.
[0138] As a preferred valve 6, as shown in FIG. 16(a), the flow
rate-adjusting portion 6d is formed at its one surface with
pressure-receiving surfaces comprising two or more inclined
surfaces 6a and 6b having different inclining angles. With this
structure, the surface of the valve 6 which receives the pressure
of the viscous fluid is formed with the bent portion and thus, it
is possible to cover a wider range of variation of the load as
compared with a valve having only one inclined surface.
[0139] The rotary damper D3 of this embodiment further comprises a
click mechanism 12. A structure of the click mechanism 12 is not
limited only if the click mechanism 12 has a function for stopping
the rotation of the rotor 7 at a predetermined rotation angle. For
example, it is possible to employ a structure in which a pair of
cam members are disposed such that their cam surfaces push against
each other, one of the cam surfaces relatively slides on the other
cam surface. If this structure using such cam members is employed,
however, the cam member itself is expensive, the rotor 7 can not
rotate smoothly due to deviated wear of the cam surface and thus, a
click mechanism 12 having the following structure is employed in
this embodiment.
[0140] That is, as shown in FIG. 12, the click mechanism 12 of this
embodiment comprises a spring member 12a disposed in the casing 1,
and a rolling member 12b. The rolling member 12b is biased by the
spring member 12a and brought into abutment against a surface
having a projection formed in the casing 1, and if the rotor 7
rotates, the rolling member 12b rolls along the abutment surface.
In this embodiment, the projection constituting the surface
(abutment surface) against which the rolling member 12b abuts
comprises a hard member 12c disposed in the recess formed in the
inner surface of the first closing portion 1f and having
predetermined hardness.
[0141] The spring member 12a comprises a coil spring. In the casing
1, one end of the spring member 12a is integrally formed on the
spring-receiving member 12d, and the other end of the spring member
12a is integrally formed with the rotor 7. The one and the other
ends of the spring member 12a are supported by end walls 7d of the
cylindrical portion 7c having outer diameters which are
substantially equal to an inner diameter of the cylindrical portion
1e which constitutes the casing 1. The spring-receiving member 12d
comprises a disk which is formed at its substantially central
portion with a hole 12e into which the rotor 7 is inserted. The
spring-receiving member 12d is provided in the cylindrical portion
7c such that the spring-receiving member 12d can move in the axial
direction along the rotor 7 (see FIGS. 12, 13 and 17).
[0142] The rolling member 12b comprises a steel ball. The rolling
member 12b is provided between the spring-receiving member 12d and
the first closing portion 1f. If the rolling member 12b is biased
by the spring member 12a through the spring-receiving member 12d,
the rolling member 12b abuts against a surface having the
projection provided in the casing 1, i.e., a surface comprising an
inner surface of the first closing portion 1f and an outer
peripheral surface of the hard member 12c in this embodiment.
Although the steel ball is employed as the rolling member 12b in
this embodiment, the rolling member 12b is not limited to this only
if the rolling member 12b has predetermined hardness and is formed
into a shape capable of rolling.
[0143] The hard members 12c comprise parallel pins and rotatably
disposed in the recesses formed in the first closing portion 1f.
Each the hard member 12c is not limited if it has the predetermined
hardness and is formed into a shape capable of forming a projection
on a flat surface such as the inner surface of the first closing
portion 1f. For example, steel balls may be employed as the hard
members 12c instead of the parallel pins. Steel balls and parallel
pins subjected to thermal treatment and having predetermined
hardness are commercially available, and they are less expensive
than producing costs or prices of parts of the cam members.
Therefore, if such commercial parts are used as the rolling member
12b or hard member 12c, the producing cost can largely be
reduced.
[0144] When the hard member 12c is not disposed, it is necessary to
form a projection of the first closing portion 1f itself and to
carry out the thermal treatment for the first closing portion 1f.
In this case also, it is possible to reduce the producing cost as
compared with a case in which the pair of cam members constituting
the mutually sliding cam surfaces must be subjected to the thermal
treatment.
[0145] According to the click mechanism 12 of this embodiment,
since the projection in which the deviated wear is most prone to be
generated comprises the hard member 12c, there are merits that this
portion is less prone to be worn and the first closing portion 1f
forming the abutment surface of the rolling member 12b need not be
subjected to the thermal treatment. Since the hard member 12c is
rotatably provided, the hard member 12c rotates when the rolling
member 12b comes into contact with the hard member 12c, the
friction generated at that time can be reduced.
[0146] The rotary damper D3 having the above-described structure is
used in the following manner. That is, when the rotary damper D3 is
used as the double lid type opening/closing supporting mechanism
comprising the outer lid and the inner lid, the casing 1 of the
rotary damper D3 is fixed to the stationary portion, and the base
end of the frame constituting the inner lid and the base end of the
frame constituting the outer lid are connected to the inner shaft
13.
[0147] Here, if the inner lid can accommodate an article, the
weight of the inner lid is largely changed between a case in which
the inner lid sufficiently accommodates the article and a case in
which the inner lid accommodates no article. When the inner lid is
closed together with the outer lid, the weight of the outer lid is
added to the weight of the inner lid. A load applied to the rotary
damper D3 is largely changed between a case in which the inner lid
accommodates no article and only the inner lid is closed, and a
case in which the inner lid sufficiently accommodates the articles
and the inner lid is closed together with the outer lid.
[0148] In this rotary damper D3, as the inner lid rotates in its
closing direction, the rotor 7 rotates in the counterclockwise
direction in FIG. 15. With this configuration, the vane 3 pushes
the viscous fluid in the first chamber 2a. With this, the flow
rate-adjusting portion 6d of the valve 6 receives the pressure of
the viscous fluid and is deformed in the direction closing the
fluid passage 5. When a load applied to the rotary damper D3 is
small, for example when no article is accommodated in the inner lid
and only the inner lid is to be closed, a force of the vane 3
pushing the viscous fluid in the first chamber 2a is weak and the
pressure of the viscous fluid is also small. Therefore, as shown in
FIG. 16(b), the flow rate-adjusting portion 6d of the valve 6 is
only slightly deformed in a direction closing the fluid passage 5
as compared with a case in which the flow rate-adjusting portion 6d
does not receive the pressure of the viscous fluid (see FIG.
16(a)).
[0149] On the other hand, when the load applied to the rotary
damper D3 is large, for example, the inner lid sufficiently
accommodates the articles and the inner lid is closed together with
the outer lid, a force of the vane 3 pushing the viscous fluid in
the first chamber 2a is strong and the pressure of the viscous
fluid is also great. Therefore, as shown in FIG. 16(c), the flow
rate-adjusting portion 6d of the valve 6 is largely deformed such
as to close a portion of the opening of the fluid passage 5 close
to the first chamber 2a by its portion having one (6a) of the two
inclined surfaces 6a and 6b having the smaller inclining angle.
[0150] When a load equal to or greater than the predetermined value
is applied, not only the portion the flow rate-adjusting portion 6d
of the valve 6 having the inclined surface 6a whose inclining angle
is small but also its portion having the inclined surface 6b whose
inclining angle is greater than that of the inclined surface 6a is
largely deformed, thereby completely closing the fluid passage 5 as
shown in FIG. 16(d).
[0151] As described above, the rotary damper D3 employs the valve 6
having the flow rate-adjusting portion 6d whose deforming degree is
changed in accordance with the variation in load like the
embodiment 1. Thus, as the load is increased, the gap between the
flow rate-adjusting portion 6d of the valve 6 and the opening of
the fluid passage 5 is reduced, and the opening can be closed
gradually. Therefore, the flow rate of the viscous fluid moving
from the first chamber 2a to the second chamber 2b through the
fluid passage 5 can be limited such that the flow rate is gradually
reduced.
[0152] Therefore, according to the rotary damper D3, it is possible
to automatically adjust the magnitude of the braking force
exhibited in correspondence with the variation in load without
operating the rotary damper D3 from outside such that the exhibited
braking force becomes small when the load is small and the
exhibited braking force when the load is great becomes great. As a
result, even if the rotational moment of the inner lid as the
subject to be controlled is changed, the variation of the rotation
speed can be reduced to an extremely small value like the
embodiment 1.
[0153] When the flow rate-adjusting portion 6d of the valve 6
completely closes the fluid passage 5, the viscous fluid can not
pass through the fluid passage 5, and the viscous fluid can move
between the first chamber 2a and the second chamber 2b only through
the small gap formed between the casing 1 and the vane 3. Thus, the
rotary damper D3 exhibits greater braking force.
[0154] On the other hand, when the inner lid is opened from its
closed state, as the inner lid rotates in its opening direction,
the rotor 7 rotates in the clockwise direction in FIG. 15 so that
the vane 3 pushes the viscous fluid in the second chamber 2b. At
that time, the flow rate-adjusting portion 6d of the valve 6 brings
the fluid passage 5 into its fully opening state as shown in FIG.
16(a). Thus, a large amount of viscous fluid in the second chamber
2b can move into the first chamber 2a through the fluid passage 5,
the rotary damper D3 does not exhibit the braking force, and the
inner lid can smoothly be opened.
[0155] Since the rotary damper D3 includes the click mechanism 12,
the inner lid can be independent in the fully opened position for
example. That is, as the inner lid is opening from its fully closed
position toward the fully opened position, the inner shaft 13 and
the rotor 7 which engages with the inner shaft 13 rotate. With
this, the rolling member 12b biased by the spring member 12a rolls
along the inner surface of the first closing portion 1f as shown in
FIG. 17(a).
[0156] When the inner lid reaches a position immediately before it
fully opens, as shown in FIG. 17(b), the rolling member 12b runs on
the top of the hard member 12c and immediately after that, i.e.,
when the inner lid reaches the fully opened position, as shown in
FIG. 17(c), the rolling member 12b rolls down from the top of the
hard member 12c along the curved surface (outer peripheral surface)
of the hard member 12c, and reaches the inner surface of the first
closing portion 1f. With this, the rotation of the inner shaft 13
and the rotor 7 is stopped, and the inner lid can be independent in
the fully opened position. On the other hand, if an external force
having a constant or higher value is applied to the inner lid in
its fully opened state, the rolling member 12b rolls in the
opposite direction, and the rolling member 12b runs across the hard
member 12c. With this, the independent state of the inner lid is
released.
[0157] According to the rotary damper D3 of this embodiment, it is
possible to automatically adjust the exhibited braking force in
correspondence with variation in load, and to stop the rotor 7 at a
predetermined rotation angle. Further, the above effect can be
obtained with the simple structure and with a single body. Thus, it
is possible to exhibit the damping function and clicking function
for the subject to be controlled with only the single rotary damper
D3.
Embodiment 4
[0158] As shown in FIGS. 18 and 19, a rotary damper D4 of this
embodiment is different from the rotary damper D3 of the embodiment
3 in that one of two through holes formed in the single vane 3 is
used as a valve hole for the valve 6 and the other through hole is
used as a valve hole for a check valve 11, and the check valve 11
is provided in addition to the valve 6.
[0159] That is, in the embodiment 3, the one vane 3 is formed with
the two fluid passages 5, and both of them function as the valve
holes for varying the flow rate of the viscous fluid moving from
the first chamber 2a to the second chamber 2b in correspondence
with variation of the load. Whereas, in the embodiment 4, as shown
in FIGS. 18 and 19, one of the two through holes formed in the one
vane 3 mainly functions as the valve hole (fluid passage 5) for the
valve 6, and the other through hole functions as the valve hole 11a
for the check valve 11.
[0160] Here, the check valve 11 may comprise a leaf spring or the
like which is independent from a leaf spring constituting the valve
6, but in order to reduce the number of parts, it is preferable
that the valve 6 and the check valve 11 comprise one leaf spring as
shown in FIG. 19(a).
[0161] The check valve 11 is provided such that it closes the valve
hole 11a when no load is applied, and only when the viscous fluid
moves from the second chamber 2b to the first chamber 2a, the check
valve 11 receives the pressure of the viscous fluid and is deformed
as shown in FIG. 19(b), and opens the valve hole 11a. With this,
when the viscous fluid moves from the second chamber 2b to the
first chamber 2a, a large amount of viscous fluid can move through
the two through holes, i.e., the fluid passage 5 and the valve hole
11a and thus, it is possible to reduce the resistance of the
viscous fluid generated at that time to an extremely small
value.
Embodiment 5
[0162] A rotary damper D5 of the embodiment 5 is different from the
rotary damper D3 of the embodiment 3 in that a spring member 16
which biases the rotor 7 which rotates in the non-braking force
exhibiting direction is provided in the casing 1 instead of the
click mechanism as shown in FIG. 20.
[0163] The spring member 16 comprises a coil spring. One end of the
spring member 16 is supported by the first closing portion 1f and
the other end is supported by the end wall 7d of the cylindrical
portion 7c. The cylindrical portion 7c has an outer diameter which
is substantially the same as an inner diameter of the cylindrical
portion 1e which constitutes the casing 1. The cylindrical portion
7c is integrally formed with the rotor 7.
[0164] The rotary damper D5 has the spring member 16. In the
example of use explained in the embodiment 3, the spring member 16
is twisted, and energy accumulated in the spring member 16 is
released when the inner lid is opened, and as the inner lid is
opened, the rotor 7 which rotates in the non-braking force
exhibiting direction is biased. Thus, the inner lid can be opened
automatically or with small force.
Embodiment 6
[0165] FIGS. 21 to 23 show an internal structure of a rotary damper
D6 of the embodiment 6. As shown FIGS. 21 to 23, the casing 1 of
the rotary damper D6 includes a cylindrical portion 1m having a
substantially circular cross section, a first closing portion in
which is integrally formed on the cylindrical portion 1m at one end
of the cylindrical portion 1m, and a second closing portion 1o
mounted to the other end of the cylindrical portion 1m by swaging.
Opposite ends of the cylindrical portion 1m are closed by the first
and second closing portions in and 1o. The first and second closing
portions in and 1o are provided at their substantially central
portions with holes 1p and 1q. The holes 1p and 1q are provided at
their peripheral edges with projections 1r and is which are fitted
into grooves 7e and 7f formed in the rotor 7 to support the rotor
7.
[0166] The rotor 7 is provided at its substantially central portion
with the hollow portion 7a. A shaft which rotates together with the
subject to be controlled is inserted into the hollow portion 7a.
The opposite end surfaces of the rotor 7 are formed with annular
grooves 7e and 7f, respectively. The rotor 7 is supported such that
the projections 1p and 1q of the first and second closing portions
in and 1o are fitted into the grooves 7e and 7f, and the rotor 7 is
rotatable relatively with the casing 1.
[0167] The partition walls 4 partition a space formed around the
rotor 7 in the casing 1. More specifically, as shown in FIG. 21,
the partition walls 4 are opposed such that they project from the
inner peripheral surface of the cylindrical portion 1m which
constitutes the casing 1 to the axial direction, and each tip end
surface of the partition wall 4 has substantially arc cross section
such that the tip end subject slides on the outer peripheral
surface of the rotor 7.
[0168] By partitioning the space around the rotor 7 by the
partition walls 4 as described above, the space formed in the
casing 1 is the fluid chamber 2, and viscous fluid such as silicon
oil is charged into the fluid chamber 2.
[0169] As shown in FIGS. 21 and 22, the vanes 3 are integrally
formed on the rotor 7 such that the vanes 3 project from the outer
peripheral surface of the rotor 7 toward the inner peripheral
surface of the cylindrical portion 1m. In this embodiment, the
vanes 3 are provided at symmetric positions with respect to the
rotor 7. As shown in FIG. 22, each vane 3 is formed into a plate
shape having such a size that as the rotor 7 rotates, a tip end
surface 3a of the vane 3 slides on the cylindrical portion 1m, an
upper end surface 3b of the vane 3 slides on the second closing
portion 1o, and a lower end surface 3c of the vane 3 slides on the
first closing portion in. Each vane 3 is formed with the fluid
passage 5 which passes through the vane 3 in its thickness
direction. The number of fluid passages 5 is not limited, and one
vane 3 may be formed with a plurality of fluid passages 5.
[0170] As shown in FIGS. 21, 23 and 24, the valve 6 includes a
surface ("opposed surface", hereinafter) 6m which is opposed to one
side surface 3d of the vane 3 at a constant distance from the one
side surface 3d of the vane 3 and which has an area capable of
closing the fluid passage 5, and a surface ("pressure-receiving
surface", hereinafter) 6n which is located on the opposite side of
the opposed surface 6m and which receives the pressure of the
viscous fluid as the vane 3 rocks. The valve 6 is integrally formed
on the vane 3 such that a portion of the valve 6 other than a root
6o projecting from the one side surface 3d of the vane 3 is not
related to any portion of the vane 3.
[0171] If the valve 6 has such resilience that if the valve 6
receives an external force, the valve 6 is deformed, and if the
external force is released, the valve 6 is returned to its original
shape. The magnitude of the external force which can deform the
valve 6 is varied depending upon how a material, a size and a shape
of the valve 6 are set. Especially, this largely depends on a width
of the root 6o of the valve 6 and a shape of the valve 6 near the
root 6o. The same can be said as to how much the valve 6 is
deformed if it receives the external force.
[0172] For example, as shown in FIG. 25, the root 6o of the valve 6
has substantially arc cross section and the vane 3 is formed at its
portion near the root 6o with a dent 3e. With this structure, the
valve 6 can be deformed such that the opposed surface 6m of the
valve 6 comes into intimate contact with the one side surface 3d of
the vane 3 and the fluid passage 5 is closed.
[0173] When no load is applied, since the opposed surface 6m of the
valve 6 is separated from the one side surface 3d of the vane 3 at
a constant distance, the fluid passage 5 is opened. On the other
hand, if the predetermined or higher load is applied to the rotary
damper D6, the pressure-receiving surface 6n receives the pressure
of the viscous fluid generated at that time and the valve 6 is
deformed, the opposed surface 6m comes into intimate contact with
the one side surface 3d of the vane 3 to close the fluid passage 5.
If the load applied to the rotary damper D6 is released, the valve
6 is returned to its original shape by the resilience of the valve
6, i.e., the valve 6 is returned to its state when no load is
applied.
[0174] If the valve 6 is disposed closer to the one side surface 3d
of the vane 3 as shown in FIG. 21, the rotary damper D6 becomes the
one-way damper in which the rotary damper D6 exhibits the braking
force in one direction only when the vane 3 rocks in the one
direction. On the other hand, the valves 6 are disposed on opposite
sides of the vane 3 (not shown), the rotary damper D6 becomes the
two-way damper in which the rotary damper D6 exhibits the braking
force not only when the vane 3 rocks in the one direction but also
when the vane 3 rocks in the opposite direction.
[0175] The rotary damper D6 having the above-described structure is
used such that the casing 1 is fixed to the stationary portion and
the shaft which rotates together with the subject to be controlled
is inserted into the hollow portion 7a of the rotor 7, and the
rotor 7 is connected to the subject to be controlled through the
shaft.
[0176] If the subject to be controlled is rotated in the one
direction, the rotor 7 connected to the subject to be controlled is
rotated in the clockwise direction in FIG. 21, and as the rotor 7
rotates, the vane 3 rocks in the clockwise direction like the rotor
7. With this, the pressure-receiving surface 6n of the valve 6
receives the pressure of the viscous fluid charged into the fluid
chamber 2.
[0177] At that time, if the load applied to the rotary damper D6 is
small, the pressure of the viscous fluid is also small and thus,
even if the pressure-receiving surface 6n receives the pressure of
the viscous fluid, the valve 6 is deformed only slightly, and only
a portion of the fluid passage 5 is closed by the valve 6. On the
other hand, if the load applied to the rotary damper D6 is great,
the pressure of the viscous fluid is also great, and the valve 6 is
deformed greater than that when the load is small, and more portion
of the fluid passage 5 is closed by the valve 6 than that when the
load is small. If the load applied to the rotary damper D6 exceeds
the predetermined value, the valve 6 is further deformed largely,
the opposed surface 6m comes into intimate contact with the one
side surface 3d of the vane 3, thereby completely closing the fluid
passage 5.
[0178] As described above, the deforming degree of the valve 6 is
varied in accordance with the variation in load. Therefore, as the
load is increased, the fluid passage 5 is, automatically closed
gradually, and it is possible to limit the flow rate of the viscous
fluid moving through the fluid passage 5 such that the flow rate is
gradually reduced. Here, the term "automatically" means "without
operating the rotary damper from outside". Thus, according to the
rotary damper D6 having such a valve 6, it is possible to
automatically adjust the magnitude of the braking force exhibited
in accordance with variation in load such that when the load is
small, the exhibited braking force becomes small, and when the load
is great, the exhibited braking force becomes great. Thus, when the
magnitude of the load is varied, it is possible to reduce the
variation in rotation speed of the subject to be controlled to an
extremely small value without operating the rotary damper D6.
[0179] In FIG. 21, when the vane 3 rocks in the counterclockwise
direction, since the valve 6 opens the fluid passage 5, the flow
rate of the viscous fluid is not limited by the valve 6 and the
viscous fluid can move through the fluid passage 5. Therefore, the
resistance of the viscous fluid becomes extremely small and thus,
the subject to be controlled rotates without being affected by the
braking force exhibited by the rotary damper D6.
[0180] Since the valve 6 employed in this embodiment is integrally
formed on the vane 3, the number of parts can be reduced as
compared with the conventional rotary damper, and the assembling
procedure of the valve 6 is unnecessary. Therefore, the producing
cost can be reduced. When the check valve is formed as an
independent member and then, the check valve is assembled as one
constituent part of the rotary damper as in the conventional
technique, there is an adverse possibility that an operator forgets
about assembling the check valve in the producing line, but by
integrally forming the valve 6 and the vane 3 together, such
possibility can be eliminated completely.
Embodiment 7
[0181] As shown in FIG. 26, a rotary damper D7 of the embodiment 7
is different from the rotary damper D6 of the embodiment 6 in that
the partition walls 4 are formed with the fluid passages 5, and the
valves 6 are integrally formed on the partition walls 4.
[0182] As shown in FIG. 26, when the fluid passages 5 are formed in
the partition walls 4 as in this embodiment, the valve 6 includes a
surface (opposed surface) 6m which is opposed to the one side
surface 4a of the partition wall 4 and which has an area capable of
closing the fluid passage 5, and a surface (pressure-receiving
surface) 6n which is located on the opposite side from the opposed
surface 6m and which receives the pressure of the viscous fluid as
the vane 3 rocks. The valve 6 is integrally formed on the partition
wall 4 such that a portion of the valve 6 other than the root 6o
projecting from the one side surface 4a of the partition wall 4 is
not related to any portion of the partition wall 4. The number of
fluid passages 5 is not limited, and one partition wall 4 may be
formed with a plurality of fluid passages 5.
[0183] When no load is applied, since the valve 6 is in a state in
which the opposed surface 6m is separated from the one side surface
4a of the partition wall 4 at the constant distance, when the valve
6 opens the fluid passage 5 and a predetermined or higher load is
applied to the rotary damper D7, the pressure-receiving surface 6n
receives the pressure of the viscous fluid generated at that time
to deform the valve 6, the opposed surface 6m comes into intimate
contact with the one side surface 4a of the partition wall 4 to
close the fluid passage 5.
[0184] If the valves 6 are disposed on the side of the one side
surfaces 4a of the partition walls 4 as shown in FIG. 26, the
rotary damper D7 becomes the one-way damper in which the rotary
damper D7 exhibits the braking force in one direction only when the
vane 3 rocks in the one direction. On the other hand, the valves 6
are disposed on opposite sides of the partition wall 4 (not shown),
the rotary damper D7 becomes the two-way damper in which the rotary
damper D7 exhibits the braking force not only when the vane 3 rocks
in the one direction but also when the vane 3 rocks in the opposite
direction.
[0185] According to the rotary damper D7 having the above-described
structure also, the same effect as that of the rotary damper D6 of
the embodiment 6 can be obtained.
Embodiment 8
[0186] As shown in FIG. 27, a rotary damper D8 according to the
embodiment 8 is different from the rotary damper D6 of the
embodiment 6 in that each of the vanes 3 is divided into two
pieces, and a valve 6 is disposed in a gap formed between the
divided pieces. Similarly, a structure in which each of the
partition walls 4 is divided into two pieces, and the valve 6 is
disposed in the gap formed between the divided pieces may also be
employed. Also when such a structure is employed, the valve 6 or
the vane 3 is integrally formed on the partition wall 4.
[0187] According to the rotary damper D8 having the above-described
structure, the valve 6 is deformed in accordance with the magnitude
of the pressure of the viscous fluid, and the flow rate of the
viscous fluid passing through the fluid passage 5 can automatically
be varied in correspondence with the variation in load irrespective
of the rocking direction of the vane 3. Therefore, it is possible
to reduce the variation of rotation speed of the subject to be
controlled to an extremely small value irrespective of the rotation
direction of the subject to be controlled without operating the
rotary damper D8.
Embodiment 9
[0188] FIG. 28 shows an internal structure of a rotary damper D9 of
the embodiment 9. As shown in FIG. 28, the rotary damper D9
comprises a rotor 7 provided in the casing 1, the fluid chambers 2
each partitioned by the partition wall 4 provided between the rotor
7 and the casing 1 and into which viscous fluid is charged, valve
bodies 18 each projecting from the rotor 7 and capable of engaging
with an engaging portion 17 disposed in the fluid chamber 2 with a
play, fluid passages 5 each formed between the valve body 18 and
the engaging portion 17, and resilient members 19 each provided in
the fluid passage 5.
[0189] The partition walls 4 projecting from the inner peripheral
surface of the casing 1 toward the axial direction are provided in
the casing 1. The tip end surface of each the partition wall 4 is
formed into a curved surface so that the outer peripheral surface
of the rotor 7 slides on the tip end surface. The rotor 7 includes
the hollow portion 7a which is hollow along the axis of the rotor
7. A shaft which serves as a rotation center of the subject to be
controlled is inserted into the hollow portion 7a.
[0190] The engaging portion 17 projects from the rotor 7 such that
the engaging portion 17 projects from the outer peripheral surface
of the rotor 7 toward the inner peripheral surface of the casing 1.
The engaging portion 17 is integrally formed on the rotor 7 such
that the engaging portion 17 constitutes a portion of the rotor 7,
and a length of the engaging portion 17 along the axial direction
is set such that when the rotor 7 is relatively rotated with
respect to the casing 1, one of the end surfaces of the engaging
portion 17 slides on a closing portion (not shown) which closes the
opening of the casing 1 and the other end surface slides on a
bottom wall of the casing 1. A length of the engaging portion 17 is
set shorter than a distance from the inner peripheral surface of
the casing 1 to the outer peripheral surface of the rotor 7 in the
radial direction. The engaging portion 17 has bifurcated tip ends,
and a gap between the bifurcated tip ends 17a and 17b forms an
engaging groove 17c into which a projection 18b of the valve body
18 engages.
[0191] The rotor 7 is rotatably provided in the casing 1. With this
structure, a space partitioned by the partition wall 4 is formed
between the rotor 7 and the casing 1. This space is the fluid
chamber 2, and viscous fluid such as silicon oil is charged into
the fluid chamber 2. The engaging portion 17 is disposed in the
fluid chamber 2.
[0192] As shown in FIG. 29, the valve body 18 is formed into a
substantially T-shape comprising an arc portion 18a having a
substantially arc shape as viewed from above, and a projection 18b
projecting from a substantially central portion of the arc portion
18a opposed to the rotor 7. Backflow grooves (first to third
backflow grooves 18c to 18e) are formed in opposed surfaces of the
arc portion 18a and the engaging portion 17 with respect to the
projection 18b and one side surface of the projection 18b. The
first to third backflow grooves 18c to 18e are formed at
substantially central portions of the above-described surfaces.
Instead of forming the first to third backflow grooves 18c to 18e
in the opposed surface of the arc portion 18a with respect to the
projection 18b, the first to third backflow grooves 18c to 18e may
be formed in the tip ends 17a and 17b of the engaging portion
17.
[0193] A length h of the valve body 18 in its axial direction is
substantially the same as the length of the engaging portion 17 in
its axial direction, and a width d of the arc portion 18a is set
wider so that the arc portion 18a comes into contact with the tip
ends 17a and 17b of the engaging portion 17.
[0194] The valve body 18 having the above-described shape is
provided in the fluid chamber 2 such that the arc portion 18a is
disposed between the engaging portion 17 and the inner peripheral
surface of the casing 1 and the projection 18b is disposed in the
engaging groove 17c with a play.
[0195] By disposing the valve body 18 in this manner, the fluid
passage 5 comprising a gap defined by the first to third backflow
grooves 18c to 18e, the tip end surface of the projection 18b and
the bottom surface of the engaging groove 32f is formed between the
valve body 18 and the engaging portion 17. The viscous fluid can
pass through the fluid passage 5. Since the width d of the arc
portion 18a is set wide so that the arc portion 18a comes into
contact with the tip ends 17a and 17b of the engaging portion 17,
when the casing 1 is rotated around the rotor 7 in the braking
force exhibiting direction X, a sliding area between the outer
peripheral surface of the arc portion 18a and the inner peripheral
surface of the casing 1 is large and thus, the adhesion between the
valve body 18a and the casing 1 is enhanced, and the sealing
performance can be enhanced.
[0196] As shown in FIG. 30, the resilient member 19 comprises a
leaf spring which is curved such that its one surface projects.
Although a member which is bent into a substantially L-shape as
viewed from side is employed as the resilient member 19 in this
embodiment, the resilient member 19 is not limited to this, and a
member which is bent into an arc shape as viewed from side can also
be employed.
[0197] It is preferable that the resilient member 19 has a notch
19a which passes through the resilient member 19 in its thickness
direction. With this notch 19a, when the casing 1 rotates around
the rotor 7 in the non-braking force exhibiting direction Y, the
viscous fluid moves through the notch 19a easily, and it is
possible to present the viscous fluid generated when the viscous
fluid passes through the fluid passage 5 from increasing as
compared with a case in which no notch 19a exists. With this, it is
possible to reduce the viscous fluid generated at that time to an
extremely low level. The same effect can also be obtained by
forming a hole passing through the resilient member 19 in its
thickness direction instead of the notch 19a.
[0198] The resilient member 19 is provided in the fluid passage 5
such that the fluid passage 5 is not closed when no load is
applied. More concretely, as shown in FIGS. 31 and 32, the
resilient member 19 is disposed in the fluid passage 5 such that
one surface of the resilient member 19 abuts against the other side
surface of the projection 18b of the valve body 18, and the other
surface abuts against an inner surface of the other tip end 17b of
the bifurcated tip ends of the engaging portion 17 opposed to the
other side surface of the 18b. It is of course possible to reverse
the positional relation between the one surface and the other
surface of the resilient member 19, and to dispose the resilient
member 19 in the fluid passage 5.
[0199] The rotary damper D9 having the above-described structure
functions as follow. That is, when the rotary damper D9 is applied
to a subject to be controlled which opens and closes and when the
subject to be controlled is closed, as shown in FIGS. 31(a) and
32(a), the valve body 18 is biased by the resilient member 19
disposed in the fluid passage 5, one of the side surfaces of the
projection 18b is in abutment against the inner surface of the one
tip end 17a of the bifurcated tip ends formed on the engaging
portion 17. When the valve body 18 is in this position, the fluid
passage 5 is fully opened.
[0200] Here, the rotary damper D9 is disposed such that the casing
1 is fixed to the subject to be controlled, the rotor 7 is
connected to the support shaft which is a rotation center of the
subject to be controlled, and as the subject to be controlled
rotates, the casing 1 rotates around the rotor 7.
[0201] If the subject to be controlled rotates in the opening
direction, the casing 1 rotates in the braking force exhibiting
direction X (see FIG. 28). With this, the partition wall 4 pushes
the viscous fluid in the fluid chamber 2. Since the rotor 7 is
provided such that the rotor 7 does not rotates even if the subject
to be controlled rotates, if the partition wall 4 pushes the
viscous fluid, the valve body 18 receives the pressure of the
viscous fluid, the valve body 18 moves in the braking force
exhibiting direction X while pressurizing the resilient member 19.
With this, the resilient member 19 is deformed as shown in FIGS.
31(b) and 32(b), the gap between the opposed surfaces of the
projection 18b of the valve body 18 and the other tip end 17b of
the engaging portion 17 is reduced, and an opening area of the
third backflow groove 18e in the fluid passage 5 is reduced.
Therefore, the flow rate of the viscous fluid passing through the
fluid passage 5 is limited. The limiting degree of the flow rate of
the viscous fluid is proportional to the magnitude of the
deformation of the resilient member 19, and as the deformation of
the resilient member 19 is greater, the flow rate of the viscous
fluid passing through the fluid passage 5 is reduced.
[0202] Therefore, when the rotational moment of the subject to be
controlled is small and the load applied to the rotary damper D9 is
small, the pressure of the viscous fluid received by the valve body
18 is also small, and deformation of the resilient member 19 caused
when the valve body 18 moves is also small. Therefore, a resistance
generated when the viscous fluid passes through the fluid passage 5
is also small and the braking force exhibited by the rotary damper
D9 is also small. On the other hand, when the rotational moment of
the subject to be controlled is great and the load applied to the
rotary damper D9 is great, the pressure of the viscous fluid
received by the valve body 18 is high and the deformation of the
resilient member 19 caused when the valve body 18 moves is also
great. Therefore, the resistance generated when the viscous fluid
passes through the fluid passage 5 is also great and the braking
force exhibited by the rotary damper D9 is also great.
[0203] According to this rotary damper D9, as the load is
increased, the fluid passage 5 can automatically be closed
gradually. Therefore, it is possible to limit the flow rate of the
viscous fluid passing through the fluid passage 5 such that the
flow rate is gradually reduced. Thus, when the magnitude of the
load is varied, it is possible to reduce the variation of the
rotation speed of the subject to be controlled to an extremely
small value even if the rotary damper D9 is not operated at
all.
[0204] When a predetermined or higher load is applied, as shown in
FIGS. 31(c) and 32(c), the resilient member 19 is largely deformed
and the fluid passage 5 is completely closed such that the gap
between the opposed surfaces of the projection 18b of the valve
body 18 and the other tip end 17b of the engaging portion 17 is
eliminated. With this, the viscous fluid can not move through the
fluid passage 5 and thus, the rotary damper D9 exhibits greater
braking force.
[0205] When the subject to be controlled is closed on the contrary,
as the subject to be controlled rotates in its closing direction,
the casing 1 rotates in the non-braking force exhibiting direction
Y (see FIG. 28). With this, the partition wall 4 pushes the viscous
fluid in the fluid chamber 2 in the opposite direction. The valve
body 18 receives the pressure of the viscous fluid pushed by the
partition wall 4 and the biasing force of the resilient member 19,
and the valve body 18 moves in the non-braking force exhibiting
direction Y, and the valve body 18 is returned to its original
position shown in FIGS. 31(a) and 32(a). With this, the fluid
passage 5 is brought into the fully opened state. Therefore, a
large amount of viscous fluid moves through the fluid passage 5 and
thus, the rotary damper D9 does not exhibit a braking force to a
degree that affects the rotational motion of the subject to be
controlled.
[0206] The present invention is not limited to the above-described
structure, and the valve body 18 may be formed into a substantially
rectangular solid havig a width smaller than that of the engaging
groove 17c, and the backflow groove through which the viscous fluid
can pass may be formed in two intersecting surfaces. The partition
wall 4 may project from the outer peripheral surface of the rotor
7, the tip end surface thereof may slide on the inner peripheral
surface of the casing 1, and the inner peripheral surface of the
casing 1 may be provided with the engaging portion 17 having the
engaging groove 17c. The engaging portion 17 may be formed into a
projecting shape, and the valve body 18 may be formed into a recess
shape.
[0207] The present invention provides an auto part having the
rotary damper according to the embodiment. Here, the term "auto
part" is not especially limited, but typical examples of the auto
part are a glove box, a console box, a reclining seat and an arm
rest. The auto part will be explained in detail below based on
embodiments illustrated in the drawings.
[0208] FIGS. 33 and 34 show the glove box disposed in an opening
formed in an instrument panel of an automobile. If the rotary
damper D9 of the embodiment 9 is applied to control the rotational
motion of the glove box 100, the rotary damper D9 is provided on a
connected portion between the glove box 100 and its support body
(instrument panel supporting the glove box 100) 110.
[0209] The box body 120 of the glove box 100 is provided at its
lower opposite sides with base portions 120a and 120b. The base
portions 120a and 120b are connected to a support body 110 which
supports the box body 120 through support shafts 130a and 130b,
respectively. The box body 120 rotates around the support shafts
130a and 130b so that an accommodating section 140 which is a space
formed in the box body 120 for accommodating articles rotates.
[0210] The casing 1 of the rotary damper D9 is fixed to the box
body 120 of the glove box 100, and the rotor 7 is connected to the
support shaft 130a. Although the rotary damper D9 is provided only
on one side of the box body 120 in the embodiment shown in FIG. 33,
the rotary dampers D9 may be disposed on the opposite sides of the
box body 120 of course. The casing 1 of the rotary damper D9 may be
fixed to the support body 110. In this case, the rotor 7 is
connected to the support shaft 130a so that the rotor 7 can rotate
in the casing 1 as the box body 120 rotates.
[0211] According to the glove box 100 having the above-described
structure, if the box body 120 rotates in its opening direction,
the accommodating section 140 turns. At that time, the magnitude of
the rotational moment of the box body 120 is different between a
case in which an article is accommodated in the accommodating
section 140 and a case in which no article is accommodated in the
accommodating section 140. Even if the article is accommodated in
the accommodating section 140, the magnitude of the rotational
moment of the box body 120 is varied depending upon the weight of
the article. Therefore, a load applied to the rotary damper D9 is
varied depending upon the presence or absence of the article
accommodated in the accommodating section 140 and the weight of the
article. According to the rotary damper D9, however, since the
exhibited braking force can automatically be adjusted in accordance
with the variation in load, the variation in rotation speed caused
by variation in rotational moment of the box body 120 can be
reduced to an extremely small value even if the rotary damper D9 is
not operated at all.
[0212] On the other hand, when the box body 120 is to be closed,
since the damping function of the rotary damper D9 does not act,
the box body 120 can rotate freely.
[0213] FIGS. 35 and 37 show the console box disposed in the
automobile. The console box 200 includes a double lid structure
comprising an outer lid 210 and an inner lid 220. If the rotary
damper D3 of the embodiment 3 is applied to control the rotational
motion of the double structure, a leg 1k projecting from the casing
1 of the rotary damper D3 is mounted to a body portion 230 of the
console box 200. With this, the casing 1 is fixed, a base end of a
frame 220a constituting the inner lid 220 and a base end of a frame
210a constituting the outer lid 210 are connected to the inner
shaft 13.
[0214] As shown in FIG. 37, the inner lid 220 of the console box
200 includes an accommodating section 220b of an article, and its
weight is largely varied between a case in which sufficient
articles are accommodated and a case in which no article is
accommodated. When the inner lid 220 and the outer lid 210 are
closed together, the weight of the outer lid 210 is also added to
the weight of the inner lid 220. Therefore, the rotational moment
of the inner lid 220 is largely varied between a case in which no
article is accommodated in the inner lid 220 and only the inner lid
220 is closed and a case in which sufficient articles are
accommodated in the inner lid 220 and the inner lid 220 and the
outer lid 210 are closed together.
[0215] According to the rotary damper D3, however, the magnitude of
the exhibited braking force can automatically be adjusted in
accordance with the variation in load such that when the load is
small, the exhibited braking force becomes small, and when the load
is great, the exhibited braking force becomes great. Therefore,
when the rotational moment of the inner lid 220 is varied, it is
possible to reduce the variation in rotation speed of the inner lid
220 to an extremely small value without operating the rotary damper
D3.
[0216] When the inner lid 220 is opened, since the damping function
of the rotary damper D3 does not act, the inner lid 220 can rotate
smoothly.
[0217] Further, since the rotary damper D3 includes the click
mechanism 12, the inner lid 220 can be independent in its fully
opened position.
[0218] FIGS. 38 and 40 shows a reclining seat disposed in an
automobile. If the rotary damper D2 of the embodiment 2 is applied
to control the rotational motion of the seat back 310 of the
reclining seat 300, the rotary damper D2 is disposed on one of
connected portions of the opposite sides between a seat back 310
and a seat cushion 320 where the reclining mechanism 330 is not
provided shown in FIG. 39. More concretely, as shown in FIGS. 39
and 40, an upper hinge bracket 350 fixed to the seat back 310 is
rotatably mounted on a support shaft 340 which supports the seat
back 310, and a lower hinge bracket 360 fixed to the seat cushion
320 is mounted on an outer side of the upper hinge bracket 350, the
rotary damper D2 is connected to the support shaft 340 from outside
of the lower hinge bracket 360, and the casing 1 is connected to
the upper hinge bracket 350 through a mounting screw 370 so that
the casing 1 can rotate around the support shaft 340 as the seat
back 310 rotates. In FIG. 40, a symbol 380 represents a nut which
is threaded around a screw portion 340a formed on a tip end of the
support shaft 340 for mounting the rotary damper D2 on the support
shaft 340.
[0219] As shown in FIG. 38, a reclining mechanism 330 capable of
adjusting a position (inclination angle) of the seat back 310 in
stages is provided on one of the connected portions on opposite
sides of the seat back 310 and the seat cushion 320. However, if
only the reclining mechanism 330 is used, since the reclining
mechanism 330 includes a spring member 331 which biases the seat
back 310 forward, if an operating lever 332 is lifted up carelessly
to release the locked state established by meshing gears 333 and
334, there is an adverse possibility that the seat back 310
abruptly rotates forwardly and collides against a seated passenger
and offends the passenger.
[0220] In this regard, according to the reclining seat 300 having
the rotary damper D2, the rotary damper D2 exhibits the braking
force to the seat back 310 which turns forward, the rotational
motion of the seat back 310 can be moderated against the biasing
force of the spring member 331 and thus, this inconvenience can be
overcome.
[0221] The rotational moment of the reclining seat 300 is varied
between a case in which a head rest (not shown) is mounted on the
seat back 310 and a case in which the head rest is detached.
Therefore, the rotation speed of the seat back 310 is largely
varied depending upon presence and absence of the head rest.
[0222] According to the rotary damper D2, however, it is possible
to automatically adjust the magnitude of the exhibited braking
force in accordance with the variation in load such that when the
load is small, the exhibited braking force becomes small, and when
the load is great, the exhibited braking force becomes great.
Therefore, when the rotational moment of the seat back 310 is
varied, it is possible to reduce the rotation speed of the seat
back 310 to an extremely small value without operating the rotary
damper D2 at all.
[0223] When the seat back 310 is rotated rearward, since the
damping function of the rotary damper D2 does not act, the seat
back 310 can be rotated with a small force.
[0224] FIGS. 41 and 42 shows an arm rest which can be accommodated
in an accommodating recess formed in a front surface of the seat
back which constitutes a rear seat of an automobile in a state in
which the arm rest stands. If the rotary damper D7 of the
embodiment 7 is applied to control the rotational motion of the arm
rest 400, the rotary damper D7 is disposed inside of a body frame
410 of the arm rest 400, and a projection it projecting from an
outer periphery of the casing 1 is engaged with an engaging pin 420
projecting from the body frame 410. With this, the casing 1 is
fixed to the body frame 410 so that the casing 1 can turn around
the support shaft 430 as the body frame 410 rotates in the
longitudinal direction, and the rotor 7 is connected to the support
shaft 430 using a connecting pin 440.
[0225] The body frame 410 of the arm rest 400 is turnably supported
by the support shaft 430 which is supported by a bracket 450
mounted on a seat back (not shown) which constitutes a rear seat of
an automobile. A guide bar 460 is provided in the body frame 410.
Opposite ends of the guide bar 460 are disposed in arc guide
grooves 450a formed in the bracket 450. A range in which the guide
bar 460 can move in the guide groove 450a as the body frame 410
turns is set as a rotation angle range of the arm rest 400 in the
longitudinal direction.
[0226] The arm rest 400 has such a structure that the arm rest 400
can be used as an arm rest of a passenger, and the arm rest 400 can
accommodate an article. Therefore, the rotational moment of the arm
rest 400 is varied between a case in which an article is
accommodated and a case in which no article is accommodated. Thus,
the rotation speed of the arm rest 400 is largely varied depending
upon presence or absence of the article.
[0227] According to the rotary damper D7, however, it is possible
to automatically adjust the magnitude of the exhibited braking
force in accordance with the variation in load such that when the
load is small, the exhibited braking force becomes small, and when
the load is great, the exhibited braking force becomes great.
Therefore, when the rotational moment of the arm rest 400 is
varied, it is possible to reduce the rotation speed of the arm rest
400 to an extremely small value without operating the rotary damper
D7 at all.
[0228] Further, when the arm rest 400 is used, the arm rest 400
which is accommodated in the accommodating recess (not shown)
formed in the front surface of the seat back in its standing
attitude is pulled out forward, and it is rotated forward. At that
time, even if a user moves his or her hand off the arm rest 400,
the arm rest 400 can rotate slowly by the damping function of the
rotary damper D7, and the arm rest 400 can stop at its using
attitude without generating an impact almost at all.
[0229] On the other hand, when the arm rest 400 is to be
accommodated, since the damping function of the rotary damper D7
does not act, the arm rest 400 can be rotated with a small
force.
[0230] The present invention provides a rotational motion assistant
mechanism which is characterized in that it has a spring member
which biases a subject to be controlled in one direction is
provided with the rotary damper of the embodiment so that rotation
of the subject to be controlled in one direction is delayed against
stress of the spring member. The invention will be explained in
detail based on an illustrated embodiment.
[0231] FIGS. 43 and 45 show a hoisting and lowering case having the
rotational motion assistant mechanism according to an embodiment of
the present invention. As shown in these drawings, the hoisting and
lowering case 500 is connected to a fixed plate 530 through a
movable arm 510 and an auxiliary arm 520. If a user grasps a handle
(not shown) and pulls it downward, the hoisting and lowering case
500 rotates from its accommodating position to its using position,
and if the user pushes the hoisting and lowering case 500 upward,
the hoisting and lowering case 500 is rotated from the using
position to the accommodating position.
[0232] The rotational motion assistant mechanism of this embodiment
includes a spring member 20, and includes the rotary damper D1 of
the embodiment 1.
[0233] The spring member 20 biases a subject to be controlled in
one direction. In this embodiment, the spring member 20 biases the
hoisting and lowering case 500 which is the subject to be
controlled upward. It is possible to employ an extension coil
spring as the spring member 20, but in this embodiment, a
spiral-spring is employed. This is because that the spiral-spring
has a merit that a small installation space suffices as compared
with the extension coil spring.
[0234] One end 20a of the spring member 20 which becomes a fulcrum
is supported by a stationary portion, and the other end 20b which
becomes an acting point is supported by a movable portion. The
spring member 20 is disposed such that as the spring member 20 is
wound as the spring member 20 is rotated when the hoisting and
lowering case 500 is lowered, energy for biasing the hoisting and
lowering case 500 upward is accumulated.
[0235] In this embodiment, as the stationary portion which supports
the one end 20a of the spring member 20, the groove id (see FIGS. 1
and 44) formed in the casing 1 of the rotary damper D1 fixed to the
fixed plate 530 is utilized. That is, the one end 20a of the spring
member 20 is engaged and supported in the groove 1d. By providing
the groove 1d for supporting the one end 20a of the spring member
20 in the casing 1 of the rotary damper D1, there is a merit that
it is unnecessary to separately form a supporting portion for
supporting the one end 20a of the spring member 20 on the fixed
plate 530 or the like. As a movable portion for fixing the other
end 20b of the spring member 20, a retaining portion 510a formed on
the movable arm 510 is utilized.
[0236] A location of the rotary damper D1 is not limited, but in
this embodiment, as shown in FIG. 44, the rotary damper D1 is fixed
to the fixed plate 530 such that the casing 1 is located in a space
formed at a substantially center of the spring member 20 comprising
the spiral-spring. With this structure, since the entire rotational
motion assistant mechanism including the spring member 20 and the
rotary damper D1 can be reduced in size, there is a merit that the
installation space of the rotational motion assistant mechanism can
be reduced. It is of course possible to independently dispose the
spring member 20 and the rotary damper D1.
[0237] The rotational motion assistant mechanism having the
above-described structure functions as follows. That is, as shown
in FIG. 45, if the hoisting and lowering case 500 is lowered from
the accommodating position to the using position, the movable arm
510 turns in the same direction ("lowering direction", hereinafter)
as the rotation direction of the hoisting and lowering case 500.
Since the other end 20b of the spring member 20 is supported by the
movable arm 510, if the movable arm 510 turns in the lowering
direction, the spring member 20 is wound up. Thus, the stress of
the spring member 20 is increased as the hoisting and lowering case
500 is lowered. The stress of the spring member 20 functions as a
force for supporting the lowering hoisting and lowering case 500
and thus, the rotational motion of the hoisting and lowering case
500 is moderated, and safety of the operation can be secured.
[0238] On the other hand, if the movable arm 510 turns as the
hoisting and lowering case 500 is lowered, the rotor 7 connected to
a support shaft 540 which rotates together with the movable arm 510
rotates in the counterclockwise direction in FIG. 1 in the casing
1. When the rotor 7 rotates in the counterclockwise direction in
this manner, a resistance of the viscous fluid generated by the
rock of the vane 3 becomes extremely small, and the braking force
exhibited by the rotary damper D1 becomes also small. Therefore,
when the hoisting and lowering case 500 is lowered, the hoisting
and lowering case 500 rotates without being affected by the damping
effect of the rotary damper D1.
[0239] On the other hand, when the hoisting and lowering case 500
is hoisted toward the accommodating position from the using
position, the stress of the spring member 20 functions as a force
for hoisting the hoisting and lowering case 500 and thus, a user
can lift the hoisting and lowering case 500 with a small force.
[0240] Since the one end 20a of the spring member 20 is supported
by the stationary portion, the spring member 20 can exhibit only
stress within a given range. Thus, if only the spring member 20 is
used, it is difficult to sufficiently assist the rotational motion
of the hoisting and lowering case 500. That is, since the hoisting
and lowering case 500 includes a shelf 550 as shown in FIG. 43 and
can accommodate an article, the weight of the entire hoisting and
lowering case 500 is varied between a case in which the article is
accommodated in the hoisting and lowering case 500 and a case in
which no article is accommodated in the hoisting and lowering case
500 or a case in which the entire weight of the articles is heavy,
and the rotational moment of the hoisting and lowering case 500 is
varied. Therefore, if there is provided only the spring member 20
which can exhibit only the stress in the given range, when the
hoisting and lowering case 500 whose entire weight is light is
lifted up from the using position to the accommodating position,
the rotation speed of the hoisting and lowering case 500 is largely
accelerated by the operating force of a user and the stress of the
spring member 20, and there is an adverse possibility that the
hoisting and lowering case 500 is abruptly rotated and stops at the
accommodating position, and a large impact is generated when the
hoisting and lowering case 500 stops. On the other hand, if the
biasing force of the spring member 20 applied to the hoisting and
lowering case 500 is set small so as to reduce the impact caused
when the hoisting and lowering case 500 stops, a burden of a user
when the hoisting and lowering case 500 whose entire weight is
heavy is lifted up from the using position to the accommodating
position becomes large.
[0241] However, since the rotational motion assistant mechanism of
this embodiment has the rotary damper D1, it is possible to
overcome the inconvenience without requiring a user to do any
special operation.
[0242] That is, according to the rotary damper D1, it is possible
to automatically adjust the magnitude of the exhibited braking
force in accordance with variation in load such that when the load
is small, the exhibited braking force becomes small, and when the
load is great, the exhibited braking force becomes great.
Therefore, even when the rotational moment of the hoisting and
lowering case 500 is varied, it is possible to adjust the biasing
force of the spring member 20 applied to the hoisting and lowering
case 500 without doing any operation. Thus, according to the
rotational motion assistant mechanism of the embodiment, it is
possible to always reduce an impact caused when the hoisting and
lowering case 500 stops at the accommodating position irrespective
of variation of rotational moment of the hoisting and lowering case
500.
[0243] Further, according to the rotational motion assistant
mechanism of this embodiment, since it is possible to always reduce
the impact when the hoisting and lowering case 500 stops at the
accommodating position, the biasing force of the spring member 20
applied to the hoisting and lowering case 500 can be set large
within a range which does not hinder the using condition. Thus,
even when the hoisting and lowering case 500 whose entire weight is
heavy is lifted up to the accommodating position from the using
position, it is possible to reduce the burden of the user.
[0244] If a predetermined or higher load is applied to the rotary
damper D1, the rotary damper D1 exhibits greater braking force.
Thus, the biasing force of the spring member 20 applied to the
hoisting and lowering case 500 (force for lifting the hoisting and
lowering case 500 by the spring member 20) can be reduced to
substantially zero by the braking force, and the rotational motion
of the hoisting and lowering case 500 can be stopped. The
rotational motion assistant mechanism of the present invention can
also be applied to various subjects in addition to the
above-described hoisting and lowering case.
INDUSTRIAL APPLICABILITY
[0245] As explained above, according to the present invention, it
is possible to provide a rotary damper which can automatically
adjust an exhibited braking force in accordance with variation in
load caused by variation of rotational moment of a subject to be
controlled, and which can reduce the variation in rotation speed of
a subject to, be controlled to an extremely small value.
[0246] Further, according to the present invention, it is possible
to provide an auto part such as a glove box, a console box, a
reclining seat, an arm rest and the like in which variation in
rotation speed is small even if the rotational moment is
varied.
[0247] Further, according to the present invention, it is possible
to provide a rotational motion assistant mechanism capable of
automatically adjusting a biasing force of a spring member applied
to a subject to be controlled in correspondence with variation of
rotational moment of the subject to be controlled.
* * * * *