U.S. patent application number 11/643898 was filed with the patent office on 2007-05-10 for rotary damper.
This patent application is currently assigned to NIFCO INC.. Invention is credited to Ken Hayashi, Masanobu Kawamoto, Masayuki Nishiyama, Shunsuke Okabayashi.
Application Number | 20070102250 11/643898 |
Document ID | / |
Family ID | 33432390 |
Filed Date | 2007-05-10 |
United States Patent
Application |
20070102250 |
Kind Code |
A1 |
Hayashi; Ken ; et
al. |
May 10, 2007 |
Rotary damper
Abstract
A rotary damper includes a housing, a viscous fluid filled in
the housing, and a rotor disposed inside the housing and having a
shaft part partially protruding from the housing. The rotor has a
plurality of rotating resistance parts provided on the shaft part
for moving in the viscous fluid inside the housing. A first sloping
part is provided on an upstream side of the rotating resistance
part to form a distance relative to an inner surface of the housing
gradually decreasing toward a downstream side, and a second sloping
part is provided on a downstream side of the rotating resistance
part to form a distance relative to the inner surface of the
housing gradually increasing toward a downstream side.
Inventors: |
Hayashi; Ken; (Aichi-gun,
JP) ; Okabayashi; Shunsuke; (Toyonaka-shi, JP)
; Kawamoto; Masanobu; (Yokohama-shi, JP) ;
Nishiyama; Masayuki; (Chigasaki-shi, JP) |
Correspondence
Address: |
KANESAKA BERNER AND PARTNERS LLP
1700 DIAGONAL RD
SUITE 310
ALEXANDRIA
VA
22314-2848
US
|
Assignee: |
NIFCO INC.
Yokohama
JP
|
Family ID: |
33432390 |
Appl. No.: |
11/643898 |
Filed: |
December 22, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10950573 |
Sep 28, 2004 |
|
|
|
11643898 |
Dec 22, 2006 |
|
|
|
Current U.S.
Class: |
188/290 |
Current CPC
Class: |
F16F 9/145 20130101 |
Class at
Publication: |
188/290 |
International
Class: |
F16D 57/00 20060101
F16D057/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 8, 2003 |
JP |
2003-349465 |
Claims
1. A rotary damper comprising: a housing, a viscous fluid filled in
the housing, a rotor disposed in the housing and having a shaft
part partially protruding from the housing and a plurality of
resistance parts extending radially outwardly from the shaft part
for moving in the viscous fluid inside the housing, a seal member
disposed between the shaft part and the housing for preventing
leakage of the viscous fluid, a first sloping part provided on at
least one of upper and lower surfaces of the resistance part at an
upstream side in a rotational direction thereof and having a
distance relative to an inner surface of the housing gradually
decreasing toward a downstream side in the rotational direction,
and a second sloping part provided on the at least one of the upper
and lower surfaces of the resistance part at the downstream side in
the rotational direction and having a distance relative to the
inner surface of the housing gradually increasing toward the
downstream side in the rotational direction.
2. A rotary damper according to claim 1, wherein said resistance
parts are provided on the poles extending radially outwardly from
the shaft part.
3. A rotary damper according to claim 2, wherein said first and
second sloping parts are formed on the upper and lower surfaces of
the poles.
4. A rotary damper according to claim 3, wherein each of said poles
has a hexagonal or elliptical cross-sectional shape.
5. A rotary damper according to claim 3, wherein each of said poles
has sharp front and read edges forming the first and second sloping
parts.
6. A rotary damper according to claim 5, further comprising a
circular flat plate arranged coaxially with the shaft part and
connecting outer edges of the resistance parts.
7. A rotary damper according to claim 1, wherein each of said
resistance parts includes a radial flat portion extending radially
outwardly from the shaft part, and an end portion provided on outer
side of the radial flat portion and facing upper and lower surface
of the housing.
8. A rotary damper according to claim 7, wherein each of said end
portion has a diamond shape.
9. A rotary damper according to claim 1, wherein said first sloping
part and said second sloping part are provided symmetrically on two
sides of the radial flat portions.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This is a divisional application of U.S. patent application
Ser. No. 10/950,573 filed on Sep. 28, 2004.
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
[0002] The invention relates to a rotary damper for damping a
rotation of a driven gear engaging a gear or a rack.
[0003] A rotary damper is formed of a housing; a viscous fluid
filled inside the housing; a rotor disposed in the housing and
having a shaft part partially protruding from the housing and a
resistance part provided on the shaft part for moving within the
viscous fluid inside the housing; and a seal member for sealing
between the shaft part of the rotor and the housing to prevent
leakage of the viscous fluid. A driven gear is attached to the
shaft part protruding from the housing (refer to Japanese Patent
Publication (Kokai) No. 04-34015).
[0004] A conventional rotary damper has a resistance part having an
elliptical shape, so that air mixed into the housing during
assembly is not allowed to be positioned between the resistance
part of a rotor, i.e. a torque generating part, and a bottom
surface or ceiling surface of the housing. However, because the
rotor rotates in both directions, the air mixed into the housing
generates a noise when the air moves over the resistance part to
the opposite side of the resistance part. The noise generated when
the air mixed into the housing moves over the resistance part is
believed to be a bursting sound caused by the air mixed into the
housing being compressed by moving up the resistance part and then
being released suddenly when moving over the resistance part. Such
a noise tends to happen more frequently when the viscous fluid has
a higher viscosity, or when a distance between the rotor and the
housing is narrower.
[0005] In view of the problem described above, an object of the
invention is to provide a rotary damper, in which air mixed into a
housing and compressed by moving up on a resistance part is
gradually released during assembly, so that it is possible to
prevent a noise caused by the air mixed into a housing even when
the rotor rotates in both directions.
[0006] Further objects and advantages of the invention will be
apparent from the following description of the invention.
SUMMARY OF THE INVENTION
[0007] In order to attain the objects described above, according to
a first aspect of the present invention, a rotary damper includes a
housing; a viscous fluid filled in the housing; a rotor disposed
inside the housing and having a shaft part partially protruding
from the housing and a resistance part provided on the shaft part
for moving in the viscous fluid inside the housing; and a seal
member for sealing between the shaft part and the housing to
prevent leakage of the viscous fluid. The rotary damper further
includes a first sloping part provided on an upstream side of the
rotating resistance part and having a distance relative to an inner
surface of the housing gradually decreasing toward a downstream
side; and a second sloping part provided on a downstream side of
the rotating resistance part and having a distance relative to the
inner surface of the housing gradually increasing toward a
downstream side.
[0008] According to a second aspect of the invention, in the rotary
damper in the first aspect, the first sloping part and second
sloping part are provided on an outer perimeter part of the
resistance part.
[0009] According to a third aspect of the invention, in the rotary
damper in the first aspect, the first sloping part and second
sloping part are provided on an inner perimeter surface of the
housing.
[0010] According to a fourth aspect of the invention, in the rotary
damper in one of the first to third aspects, a plurality of the
first sloping parts and second sloping parts are provided.
[0011] In the first aspect of the invention, the rotary damper
includes the first sloping part provided on an upstream side of the
rotating resistance part and having a distance relative to the
inner surface of the housing gradually decreasing toward a
downstream side; and the second sloping part provided on a
downstream side of the rotating resistance part and having a
distance relative to the inner surface of the housing gradually
increasing toward a downstream side. Even if air mixed into the
housing flows into between the inner surface of the housing and the
first sloping part during assembly, the air is gradually compressed
and then is gradually released. Accordingly, it is possible to
prevent generation of a noise caused by the air mixed into the
housing even when the rotor rotates in both directions.
[0012] In the second aspect of the invention, the first sloping
part and second sloping part are provided on the outer perimeter
part of the resistance part, where a negative pressure tends to be
generated most easily when the rotor rotates. In the third aspect
of the invention, the first sloping part and second sloping part
are provided on the inner perimeter surface of the housing.
Accordingly, it is possible to effectively prevent generation of a
noise caused by the air mixed into the housing.
[0013] In the fourth aspect of the invention, a plurality of the
first sloping parts and second sloping parts are provided.
Accordingly, it is possible to adjust torque within a wide range
and increase the torque regardless of a position of the air mixed
into the housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a sectional view of a rotary damper according to a
first embodiment of the invention;
[0015] FIG. 2 is a perspective view of a rotor shown in FIG. 1;
[0016] FIG. 3 is a perspective view of a rotor constituting a
rotary damper according to a second embodiment of the
invention;
[0017] FIG. 4 is a sectional view of a radial pole taken along line
4-4 in FIG. 3;
[0018] FIG. 5 is a sectional view of a rotor constituting a rotary
damper according to a third embodiment of the invention;
[0019] FIG. 6 is a perspective view of a rotor constituting a
rotary damper according to a fourth embodiment of the
invention;
[0020] FIG. 7 is a sectional view taken along line 7-7 in FIG.
6;
[0021] FIG. 8 is a perspective view of a rotor constituting a
rotary damper according to a fifth embodiment of the invention;
[0022] FIG. 9 is a perspective view of a rotor constituting a
rotary damper according to a sixth embodiment of the invention;
[0023] FIG. 10 is a plan view of a rotor constituting a rotary
damper according to a seventh embodiment of the invention; and
[0024] FIG. 11 is a perspective view of a rotor constituting a
rotary damper according to an eighth embodiment of the
invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0025] Hereunder, embodiments of the invention will be explained
with reference to the accompanying drawings. FIG. 1 is a sectional
view of a rotary damper according to a first embodiment of the
invention, and FIG. 2 is a perspective view of the rotor shown in
FIG. 1.
[0026] As shown in FIG. 1, a rotary damper D includes a case 11
made of a synthetic resin; silicone oil 21 as a viscous fluid
filled inside the case 11; and a rotor 31 made of a synthetic resin
and disposed inside the case 11. The rotor 31 has a shaft part 32
partially protruding from the case 11, and resistance parts 36
provided on the shaft part 32 for moving within the silicone oil 21
inside the case 11. The rotary damper D further includes a cap 61
made of a synthetic resin for closing an opening of the case 11 and
having a through-hole 62 for inserting the shaft part 32 of the
rotor 31; an O-ring 71 as a seal member for sealing between this
cap 61 and the shaft part 32 of the rotor 31 to prevent leakage of
the silicone oil 21; and a driven gear 81 made of a synthetic resin
and attached to the shaft part 32 of the rotor 31 projecting from
the cap 61. A housing is formed of the case 11 and the cap 61.
[0027] The case 11 is formed of a case main body 12 having a bottom
part 13 with a circular planar shape and a cylindrical wall part 14
extending along an outside edge of the bottom part 13; a
cylindrical bearing part 16 provided in the center of an inner
surface 13a of the bottom part 13; and attachment flanges 17
provided on an outer perimeter of the case body 12 in a radial
direction at, for example, a 180-degree interval, and having an
attachment hole 18.
[0028] An encircling thin protruding cylindrical part 14b protrudes
from an upper side of the cylindrical wall part 14, and has an
inner surface extending from an inner perimeter surface 14a of the
cylindrical wall part 14. A receiving part 15 is formed inside the
case main body 12 for retaining the silicone oil 21, and
corresponds to a part below the thin protruding cylindrical part
14b.
[0029] The rotor 31 is formed of the shaft part 32 with a
cylindrical shape, and a plurality of, in the embodiment two
provided at a 180-degree interval, resistance parts 36 extending
from the shaft part 32 outwardly in a radial direction. A recess 33
with a cylindrical shape is formed on a bottom surface of the shaft
part 32 for engaging a bearing part 16 of the case 11 to be
rotatable. The shaft part 32 is also provided with I-cut sections
34 at a part thereof protruding from the cap 61, and horizontal
coupling grooves 35 on a plane part (perpendicular plane) of each
of the I-cut sections, respectively.
[0030] As shown in FIG. 2, each of the resistance part 36 is formed
of a radial flat plate 37 extending horizontally and radially from
the shaft part 32, and an arc-shaped plate 38 provided on an outer
perimeter edge of the radial flat plate 37 in the circumferential
direction and facing an inner surface of the case 11, i.e. the
inner perimeter surface 14a of the cylindrical wall part 14.
Further, sloping parts 39A and 39B are provided on the arc-shaped
plate 38 at both ends thereof in the horizontal direction, as shown
in FIG. 2, so that a distance gradually decreases toward a center
side.
[0031] When the rotor 31 rotates in a clockwise direction in FIG.
2, the sloping parts 39A become a first sloping part positioned at
an upstream side of the resistance parts 36, where a distance
relative to the inner perimeter surface 14a of the cylindrical wall
part 14 gradually decreases toward a downstream side, and the
sloping parts 39B become a second sloping part positioned at a
downstream side of the resistance parts 36, where a distance
relative to the inner perimeter surface 14a of the cylindrical wall
part 14 gradually increases toward a downstream side. Also, when
the rotor 31 rotates in the counterclockwise direction in FIG. 2,
the sloping parts 39B become the first sloping part, and the
sloping parts 39A become the second sloping part.
[0032] A through-hole 62 is provided at the center of the
above-mentioned cap 61 for inserting the shaft part 32 of the rotor
31. An enlarged diameter section 63 having a cylindrically cut out
portion reaching a bottom end is provided on a lower side of the
through-hole 62 for receiving an O-ring 71. An encircling coupling
recess 64 is provided around an outside edge of the cap 61 at a
lower side for engaging the thin protruding cylindrical part 14b of
the case main body 12. Reference numeral 61a indicates an inner
surface (lower surface) of the cap 61. An I-cut attachment hole 82
is provided at a center of the driven gear 81, and a coupling band
83 is provided on a flat planar part of the attachment hole 82 for
engaging the coupling groove 35 provided on the shaft part 32 of
the rotor 31.
[0033] A process of assembling the rotary damper D will be
explained next. First, the shaft part 32 of the rotor 31 is
inserted into the O-ring 71, and silicone oil 21 is applied to the
recess 33 and the resistance parts 36. Then, a part of the shaft
part 32 and the resistance parts 36 are installed inside the
receiving part 15 so that the bearing part 16 of the case 11 is
fitted into the recess 33. After a suitable quantity of silicone
oil 21 is filled into the receiving part 15, the thin protruding
cylindrical part 14b is fitted into the coupling recess 64 of the
cap 61 while the shaft part 32 is inserted into the through-hole
62, and the opening of the case 11 is closed with the cap 61.
[0034] When the opening of the case 11 is closed with the cap 61,
almost all of the air inside the thin protruding cylindrical part
14b is discharged to the outside of the case 11. The thin
protruding cylindrical part 14b closely contacts the cap 61, and
the O-ring 71 is retained inside the enlarged diameter section 63
to prevent leakage of the silicone oil 21 from between the shaft
part 32 and the cap 61. Then, the thin protruding cylindrical part
14b and the cap 61 are sealed around tightly together with, for
example, high-frequency welding. When the shaft part 32 protruding
from the cap 61 is pressed into the attachment hole 82 of the
driven gear 81, the coupling band 83 is fitted into the coupling
groove 35, thereby completing the assembly of the rotary damper
D.
[0035] An operation of the rotary damper D will be explained next.
First, when the rotor 31 rotates in the clockwise direction in FIG.
2, the resistance part 36 rotates in the clockwise direction within
the silicone oil 21. Since viscosity and shear resistance of the
silicone oil 21 acts on the resistance part 36, the rotation of the
rotor 31 is damped. Accordingly, rotation or movement of a gear,
rack, or the like engaging the driven gear 81 attached to the rotor
31 is damped and slowed down.
[0036] When the rotor 31 rotates in the clockwise direction, on the
downstream side of the resistance parts 36, a part of the air mixed
into the case 11 during the assembly moves and follows a negative
pressure part generated at a downstream side of the sloping parts
39B of the resistance parts 36. Also, on the upstream side of the
resistance parts 36, a part of the air mixed into the case 11
during the assembly is gradually released between the inner
perimeter surface 14a and the outer perimeter surfaces of the
sloping parts 39B, and moves to follow the negative pressure part
generated at a downstream side of the sloping parts 39B, after
being gradually compressed between the inner perimeter surface 14a
of the cylindrical wall part 14 and the outer perimeter surfaces of
the sloping parts 39A. The rest of the air mixed into the case 11
during the assembly passes above and below the radial flat plates
37 in a virtually non-compressed state, and moves so as to follow
the negative pressure part generated at a downstream side of the
sloping parts 39B.
[0037] When the rotor 31 rotates in the counterclockwise direction
in FIG. 2, the resistance parts 36 rotate in the counterclockwise
direction within the silicone oil 21. Since the viscosity and shear
resistance of the silicone oil 21 acts on the resistance parts 36,
the rotation of the rotor 31 is damped. Accordingly, the rotation
or movement of a gear, rack, or the like engaging the driven gear
81 attached to the rotor 31 is damped and slowed down.
[0038] When the rotor 31 rotates in the counterclockwise direction,
a large part of the air following the negative pressure part
generated at the downstream side of the sloping parts 39B when the
rotor 31 rotates in the clockwise direction passes above and below
the radial flat plates 37 in a virtually non-compressed state, and
moves following a negative pressure part generated at the
downstream side of the sloping parts 39A. A part of the air is
gradually compressed between the inner perimeter surface 14a and
the outer perimeter surfaces of the sloping parts 39B, and then is
gradually released between the inner perimeter surface 14a and the
outer perimeter surfaces of the sloping parts 39A. Incidentally,
torque is generated at a part between the inner perimeter surface
14a of the cylindrical wall part 14 and the outer perimeter surface
of the rotor 36.
[0039] According to the first embodiment of the invention as
described above, the sloping parts 39A and 39B (first sloping part
and second sloping part) are provided with respect to the inner
perimeter surface 14a of the cylindrical wall part 14. Accordingly,
a part of the air mixed into the case 11 during the assembly is
gradually compressed between the inner perimeter surface 14a and
the sloping parts 39A (or sloping parts 39B), and then is gradually
released between the inner perimeter surface 14a and the sloping
parts 39B (or sloping parts 39A). Therefore, even if the rotor 31
rotates in both directions, the air mixed into the case 11 is no
longer released suddenly, so that it is possible to prevent the
generation of a noise caused by the air mixed into the case 11.
Further, the sloping parts 39A and 39B are provided on the outer
perimeter parts of the resistance parts 36 where a negative
pressure tends to be generated most easily when the rotor 31
rotates, it is possible to effectively prevent the generation of a
noise caused by the air mixed into the case 11.
[0040] FIG. 3 is a perspective view of a rotor constituting a
rotary damper according to a second embodiment of the invention,
and FIG. 4 is a sectional view of a radial pole taken along line
4-4 in FIG. 3. The same symbols are assigned to the same or
corresponding parts shown in FIG. 1 and FIG. 2, and their
explanations are omitted. In these drawings, the rotor 31 made of a
synthetic resin is held inside the case 11, and is formed of the
shaft part 32 partially protruding from the case 11, and a
plurality of resistance parts 36, in the embodiment two provided at
a 180-degree interval, extending horizontally and radially from the
shaft part 32.
[0041] Each of the resistance part 36 is formed of a radial pole 40
extending radially from the shaft part 32, and an arc-shaped plate
42 provided on an outer perimeter edge of the radial pole 40 in the
circumferential direction and facing the inner surface of the case
11, that is, the inner perimeter surface 14a of the cylindrical
wall part 14.
[0042] As shown in FIG. 4, the above-mentioned radial poles 40 have
a hexagonal cross-section. Two lower surfaces are sloping surfaces
(sloping parts) 40a and 40b in which a center in a width direction
moves toward and away from the inner surface 13a of the bottom part
13 of the case 11 from both ends in the width direction toward the
center. Two upper surfaces are sloping surfaces (sloping parts) 40c
and 40d in which a center in the width direction moves toward and
away from the inner surface 61a of the cap 61 from both ends in the
width direction toward the center.
[0043] When the rotor 31 rotates in the clockwise direction in FIG.
3, the sloping parts 40a become a first sloping part positioned on
the upstream side of the resistance parts 36, where the distance
with respect to the inner surface 13a of the bottom part 13
gradually becomes narrower toward the downstream side. The sloping
parts 40b become a second sloping part positioned on the downstream
side of the resistance parts 36, where the distance with respect to
the inner surface 13a of the bottom part 13 gradually becomes wider
toward the downstream side. The sloping parts 40c become a first
sloping part positioned on the upstream side of the resistance
parts 36, where the distance with respect to the inner surface 61a
of the cap 61 gradually becomes narrower toward the downstream
side. The sloping parts 40d become a second sloping part positioned
on the downstream side of the resistance parts 36, where the
distance with respect to the inner surface 61a of the cap 61
gradually becomes wider toward the downstream side. Accordingly,
when the rotor 31 rotates in the counterclockwise direction in FIG.
3, the sloping parts 40b and 40d become the first sloping part, and
the sloping parts 40a and 40c become the second sloping part.
[0044] Because the assembly and operation of the rotary damper D in
the second embodiment are the same as in the first embodiment,
their explanations are omitted.
[0045] When the rotor 31 rotates forward, the air mixed into the
case 11 during the assembly moves so as to follow a negative
pressure part generated at the downstream side of the arc-shaped
plates 42 of the resistance parts 36. When the rotor 31 rotates in
reverse, the air following the negative pressure part generated at
the downstream side of the arc-shaped plates 42 when the rotor 31
rotates [forward] does not pass between the inner perimeter surface
14a of the cylindrical wall part 14 and the outer perimeter
surfaces of the arc-shaped plates 42 (resistance part 36), i.e. the
torque generating part, and passes above and below the radial poles
40 and moves toward the negative pressure part generated at the
downstream side of the arc-shaped plates 42 on the opposite
side.
[0046] Thus, the air passing above and below the radial poles 40,
for example, is gradually compressed between the inner perimeter
surfaces 14a and 61a and the sloping surfaces 40a and 40c (or
sloping surfaces 40b and 40d), and then is gradually released
between the inner perimeter surfaces 14a and 61a and the sloping
surfaces 40b and 40d (or sloping surfaces 40a and 40c). In the
second embodiment, the same effect as in the first embodiment can
be obtained. Also, because the sloping surfaces 40a to 40d are
provided along the radial direction, the generation of noise can be
prevented without depending on a position of the air mixed into the
case 11, thereby increasing torque and a range of adjusting the
torque.
[0047] FIG. 5 is a sectional view of a rotor constituting a rotary
damper according to a third embodiment of the invention. The same
symbols are assigned to the same or corresponding parts as in FIGS.
1 to 4, and their explanations are omitted. FIG. 5 is a sectional
view similar to FIG. 4. A only difference from the rotor shown in
FIG. 3 is an elliptical sectional shape of the radial poles
constituting the rotor. The rotor 31 made of a synthetic resin
shown in FIG. 5 is held inside the case 11, and is formed of the
shaft part 32 partially protruding from the case 11, and two
resistance parts 36 provided at a 180-degree interval and extending
horizontally and radially from the shaft part 32.
[0048] Each of the resistance part 36 is formed of the radial pole
41 extending radially from the shaft part 32, and the arc-shaped
plate 42 provided on the outer perimeter edge of this radial pole
41 in the circumferential direction and facing the inner surface of
the case 11, that is, the inner perimeter surface 14a of the
cylindrical wall part 14.
[0049] The above-mentioned radial poles 41 have an elliptical
sectional shape with a horizontal long axis (parallel to the inner
surface 13a of the bottom part 13 and the inner surface 61a of the
cap 61) and a vertical short axis (perpendicular to the inner
surface 13a of the bottom part 13 and the inner surface 61a of the
cap 61). The surface on the lower side is formed in the sloping
surfaces (sloping parts) 41a and 41b in which the center in the
width direction moves toward and away from the inner surface 13a of
the bottom part 13 of the case 11 from both ends in the width
direction toward the center. The surface on the upper side is
formed in the sloping surfaces (sloping parts) 41c and 41d in which
the center in the width direction moves toward and away from the
inner surface 61a of the cap 61 from both ends in the width
direction toward the center.
[0050] When the rotor 31 rotates in the clockwise direction in FIG.
3, the sloping surface 41a becomes a first sloping part positioned
on the upstream side of the resistance part 36, where the distance
gradually becomes narrower toward the downstream side with respect
to the inner surface 13a of the bottom part 13, and the sloping
surface 41b becomes a second sloping part positioned on the
downstream side of the resistance part 36, where the distance
gradually becomes wider toward the downstream side with respect to
the inner surface 13a of the bottom part 13. Also, the sloping
surface 41c becomes a first sloping part positioned on the upstream
side of the resistance part 36, where the distance gradually
becomes narrower toward the downstream side with respect to the
inner surface 61a of the cap 61, and the sloping surface 41d
becomes a second sloping part positioned on the downstream side of
the resistance part 36, where the distance gradually becomes wider
toward the downstream side with respect to the inner surface 61a of
the cap 61.
[0051] Also, when the rotor 31 rotates in the counterclockwise
direction in FIG. 3, the sloping surfaces 41b and 41d become the
first sloping part, and the sloping surfaces 41a and 41c become the
second sloping part. Because the assembly and operation of the
rotary damper D in the third embodiment are the same as in the
first embodiment, their explanations are omitted. Also, because the
flow (movement) of the air mixed into the case 11 during the
assembly is the same as in the second embodiment, its explanation
is omitted. In the third embodiment, the same effect as in the
first or second embodiment can be obtained.
[0052] FIG. 6 is a perspective view of a rotor constituting a
rotary damper according to a fourth embodiment of the invention,
and FIG. 7 is a sectional view taken along line 7-7 in FIG. 6. The
same symbols are assigned to the same or corresponding parts as in
FIGS. 1 to 5, and their explanations are omitted. In these
drawings, the rotor 31 made of a synthetic resin is held inside the
case 11, and is formed of the shaft part 32 partially protruding
from the case 11, and the resistance part 36 comprising a circular
flat plate 43 with a circular planar shape connected horizontally
to the shaft part 32.
[0053] Also, on the circular flat plate 43 (resistance part 36), as
shown in FIG. 7, there are provided three rectangular holes (slits)
44 extending radially at positions separated by 120 degrees. In
addition, there are provided sloping parts 45A and 45B extending
from both sides in the circumferential direction toward each of the
holes 44 and having inclined upper and lower sides moving toward
and away from each other.
[0054] When the rotor 31 rotates in the clockwise direction in FIG.
6, the sloping parts 45A become the first sloping part positioned
on the upstream side of the resistance part 36, where the distance
gradually becomes narrower toward the downstream side with respect
to the inner surface 13a of the bottom part 13 and the inner
surface 61a of the cap 61. The sloping parts 45B become the second
sloping part positioned on the downstream side of the resistance
part 36, where the distance gradually becomes wider toward the
downstream side with respect to the inner surface 13a of the bottom
part 13 and the inner surface 61a of the cap 61. Also, when the
rotor 31 rotates in the counterclockwise direction in FIG. 6, the
sloping parts 45B become the first sloping part, and the sloping
parts 45A become the second sloping part.
[0055] In the fourth embodiment, torque generation parts are
located between the inner perimeter surface 14a and the outer
perimeter surface of the rotor 36 (circular flat plate 43), and
between the upper and lower surfaces of the rotor 36 (circular flat
plate 43) and the inner surfaces 13a and 61a. Because the assembly
and operation of the rotary damper D in the fourth embodiment are
the same as in the first embodiment, their explanations are
omitted.
[0056] As for the flow (movement) of the air mixed into the case 11
during the assembly, for example, the air is gradually compressed
between the sloping parts 45A (or sloping parts 45B) and the inner
surfaces 13a and 61a, and then is gradually released between the
sloping parts 45B (or sloping parts 45A) and the inner surfaces 13a
and 61a. Also, the air flowing into one of the holes 44 from the
sloping parts 45A or the sloping parts 45B moves following a
negative pressure part generated at the downstream side of the
sloping parts 45A or the sloping parts 45B, and tends not to flow
into the other of the holes 44.
[0057] In the fourth embodiment, the same effect as in the
first-third embodiments can be obtained. Also, in the fourth
embodiment, even if the holes 44 are not provided, an effect same
as that in the first to third embodiments can be obtained.
[0058] FIG. 8 is a perspective view of a rotor constituting a
rotary damper according to a fifth embodiment of the invention. The
same symbols are assigned to the same or corresponding parts in
FIGS. 1 to 7, and their explanations are omitted.
[0059] The rotor 31 made of a synthetic resin shown in FIG. 8 is
held inside the case 11, and is formed of the shaft part 32
partially protruding from the case 11, and the resistance part 36
comprising a radial flat plate 46 having an I-cut circle planar
shape extending from the shaft part 32 horizontally and radially at
a 180-degree interval.
[0060] On the radial flat plate 46 (resistance part 36), there are
provided sloping surfaces (sloping parts) 46a and 46b extending to
an outer perimeter on both upper sides at the upstream side and the
downstream side in the rotational direction.
[0061] When the rotor 31 rotates in the clockwise direction, the
sloping surfaces 46a become the first sloping part positioned on
the upstream side of the resistance part 36, where the distance
gradually becomes narrower toward the downstream side with respect
to the inner surface 61a of the cap 61, and the sloping surfaces
46b become the second sloping part positioned on the downstream
side of the resistance part 36, where the distance gradually
becomes wider toward the downstream side with respect to the inner
surface 61a of the cap 61. Also, when the rotor 31 rotates in the
counterclockwise direction, the sloping surfaces 46b become the
first sloping part, and the sloping surfaces 46a become the second
sloping part.
[0062] Because the assembly and operation of the rotary damper D in
the fifth embodiment are the same as in the first embodiment, their
explanations are omitted. Also, because the flow (movement) of the
air mixed into the case 11 during the assembly is the same as in
the second embodiment, its explanation is omitted. In the fifth
embodiment also, the same effect as in the first to fourth
embodiments can be obtained.
[0063] FIG. 9 is a perspective view of a rotor constituting a
rotary damper according to a sixth embodiment of the invention. The
same symbols are assigned to the same or corresponding parts as in
FIGS. 1 to 8, and their explanations are omitted.
[0064] The rotor 31 made of a synthetic resin shown in FIG. 9 is
held inside the case 11, and is formed of the shaft part 32
protruding from the case 11, and two resistance parts 36 extending
horizontally and radially at a 180-degree interval from the shaft
part 32. Also, each of the resistance parts 36 is formed of a
radial flat plate 47 connected to the shaft part 32, and a flat
diamond-shaped projection 48 connected to an outer perimeter
surface of the radial flat plate 47 and having sloping surfaces 48a
and 48b at an upper side and a lower side, respectively.
[0065] When the rotor 31 rotates in the clockwise direction, the
sloping surfaces 48a become the first sloping part positioned on
the upstream side of the resistance parts 36, where the distance
gradually becomes narrower going downstream with respect to the
inner surface 13a of the bottom part 13 and the inner surface 61a
of the cap 61. The sloping surfaces 48b become the second sloping
part positioned on the downstream side of the resistance parts 36,
where the distance gradually becomes wider going downstream with
respect to the inner surface 13a of the bottom part 13 and the
inner surface 61a of the cap 61. Also, when the rotor 31 rotates in
the counterclockwise direction, the sloping surfaces 48b become the
first sloping part, and the sloping surfaces 48a become the second
sloping part.
[0066] Because the assembly and operation of the rotary damper D in
the sixth embodiment are the same as in the first embodiment, their
explanations are omitted. Also, because the flow (movement) of the
air mixed into the case 11 during the assembly is the same as in
the second embodiment, its explanation is omitted. In the sixth
embodiment also, the same effect as in the first to fifth
embodiments can be obtained.
[0067] FIG. 10 is a plan view of a rotor constituting a rotary
damper according to a seventh embodiment of the invention. The same
symbols are assigned to the same or corresponding parts as in FIGS.
1 to 9, and their explanations are omitted.
[0068] The rotor 31 made of a synthetic resin shown in FIG. 10 is
held inside the case 11, and is formed of the shaft part 32
partially protruding from the case 11, and the resistance parts 36
extending outward horizontally and radially at a 90-degree interval
from the shaft part 32 and comprising spherical union bodies 49
having spheres connected like dumplings. Also, on each of the
spherical union bodies 49 (resistance parts 36), there are provided
hemispheric surfaces (sloping parts) 49a and 49b on both upper
sides at the upstream side and the downstream side in the
rotational direction.
[0069] When the rotor 31 rotates in the clockwise direction, the
hemispheric surfaces 49a become the first sloping part positioned
on the upstream side of the resistance part 36, where the distance
gradually becomes narrower toward the downstream side with respect
to the inner surface 13a of the bottom part 13, the inner perimeter
surface 14a of the cylindrical wall part 14, and the inner surface
61a of the cap 61, and the hemispheric surfaces 49b become the
second sloping part positioned on the downstream side of the
resistance part 36, where the distance gradually becomes wider
toward the downstream side with respect to the inner surface 13a of
the bottom part 13, the inner perimeter surface 14a of the
cylindrical wall part 14, and the inner surface 61a of the cap 61.
Also, when the rotor 31 rotates in the counterclockwise direction,
the hemispheric surfaces 49b become the first sloping part, and the
hemispheric surfaces 49a become the second sloping part.
[0070] Because the assembly and operation of the rotary damper D in
this seventh embodiment are the same as in the first embodiment,
their explanations are omitted. Also, because the flow (movement)
of the air mixed into the case 11 during assembly is the same as in
the second embodiment, its explanation is omitted. In the seventh
embodiment also, the same effect as in the first to sixth
embodiments can be obtained.
[0071] FIG. 11 is a perspective view of a rotor constituting a
rotary damper according to an eighth embodiment of the invention.
The same symbols are assigned to the same or corresponding parts in
FIGS. 1 to 10, and their explanations are omitted.
[0072] The rotor 31 made of a synthetic resin shown in FIG. 11 is
held inside the case 11, and is formed of the shaft part 32
partially protruding from the case 11, and the resistance part 36
comprising a radial flat plate 50 having a I-cut circle planar
shape and extending horizontally and radially at a 180-degree
interval from the shaft part 32. Also, on the radial flat plate 50
(resistance part 36), there are provided plural triangularly shaped
cut-outs 51A and 51B recessed from an outside of the radial flat
plate 50 toward an inside of the radial flat plate 50, that is,
having a long side of the radial flat plate 50 as a base, on both
sides at the upstream side and the downstream side in the
rotational direction.
[0073] When the rotor 31 rotates in the clockwise direction, the
cut-outs 51A become the first sloping part positioned on the
upstream side of the resistance part 36, where the distance
gradually becomes narrower toward the downstream side with respect
to the inner surface 13a of the bottom part 13 and the inner
surface 61a of the cap 61, and the cut-outs 51B become the second
sloping part positioned on the downstream side of the resistance
part 36, where the distance gradually becomes wider toward the
downstream side with respect to the inner surface 13a of the bottom
part 13 and the inner surface 61a of the cap 61. Also, when the
rotor 31 rotates in the counterclockwise direction, the cut-outs
51B become the first sloping part, and the cut-outs 51A become the
second sloping part.
[0074] Because the assembly and operation of the rotary damper D in
the eighth embodiment are the same as in the first embodiment,
their explanations are omitted. Also, because the flow (movement)
of the air mixed into the case 11 during assembly is the same as in
the second embodiment, its explanation is omitted. In the eighth
embodiment, the same effect as in the first to sixth embodiments
can be obtained.
[0075] In the above-mentioned embodiments, the examples have been
shown, in which the rotor 31 is rotatable supported with the
bearing part 16 on the case 11 and the recess 33 on the shaft part
32. The rotor may be constituted such that the recess is provided
on the case and the bearing part is provided on the shaft. Also, in
the embodiments, the torque is generated mainly between the inner
perimeter surface 14a of the case 11 and the outer perimeter
surface of the resistance body 36. It also may be constituted such
that the torque is generated mainly between the inner perimeter
surface of the cap and the outer perimeter surface of the
resistance body.
[0076] Also, in the embodiments, the housing is formed of the case
11 and the cap 61. The receiving part 15 for the silicone oil 21 is
provided in the case 11. The through-hole 62 is provided in the cap
61 for inserting the shaft part 32 of the rotor 31, and the O-ring
71 is provided for sealing between the cap 61 and the shaft part 32
to prevent leakage of the silicone oil 21. It also may be
constituted such that the receiving part for the silicone oil is
provided in the cap, and the through-hole for inserting the shaft
part of the rotor is provided in the case. The O-ring is provided
for sealing between the case and the shaft to prevent leakage of
the silicone oil.
[0077] Also, the silicone oil 21 is used as the viscous fluid, but
other viscous fluids functioning in the same manner, for example
such as grease, also can be used. Also, the resistance part 36 is
integrally formed on the shaft part 32, but it also may be
constituted such that the shaft part and the resistance part are
molded separately, and have a square shaft and a square hole to
rotate integrally.
[0078] The disclosure of Japanese Patent Application No.
2003-349465, filed on Oct. 8, 2003, is incorporated in the
application.
[0079] While the invention has been explained with reference to the
specific embodiments of the invention, the explanation is
illustrative and the invention is limited only by the appended
claims.
* * * * *