U.S. patent application number 09/395561 was filed with the patent office on 2002-04-11 for transmission.
This patent application is currently assigned to LOWE HAUPTMAN GILMAN & BERNER, LLP. Invention is credited to MIMURA, KENJI.
Application Number | 20020042314 09/395561 |
Document ID | / |
Family ID | 26517150 |
Filed Date | 2002-04-11 |
United States Patent
Application |
20020042314 |
Kind Code |
A1 |
MIMURA, KENJI |
April 11, 2002 |
TRANSMISSION
Abstract
The present invention provides a transmission capable of surely
transmitting power even in a configuration in which the diameter of
a rotating body is changed. When movable members of the rotating
body are moved in the radial direction, the diameter of a winding
member that is wound around the movable members increases or
decreases, so that the speed reducing ratio with respect to the
other rotating body changes. In this case, the circumferential
length of the winding member that is wound around the movable
members is changed by causing the other end side of the winding
member to go in or out through between the movable members. At this
time, since the circumferential length of the winding member
changes stepwise by the predetermined number of the engagement
portions of the winding member, the engagement portions of the
transmitting member can always be engaged surely with the
engagement portions of the winding member even if the speed is
changed. Also, since bending points of the winding member and the
transmitting member engaging with each other come to almost the
same positions, the positions of bending points of the winding
member and the transmitting member do not change relatively when
the winding member and the transmitting member are bent.
Inventors: |
MIMURA, KENJI; (KANAGAWA,
JP) |
Correspondence
Address: |
LOWE HAUPTMAN GOPSTEIN & BERNER LLP
1700 DIAGONAL ROAD
SUITE 310
ALEXANDRIA
VA
22314
|
Assignee: |
LOWE HAUPTMAN GILMAN & BERNER,
LLP
|
Family ID: |
26517150 |
Appl. No.: |
09/395561 |
Filed: |
September 14, 1999 |
Current U.S.
Class: |
474/56 ; 474/47;
474/49; 474/50 |
Current CPC
Class: |
F16H 55/54 20130101 |
Class at
Publication: |
474/56 ; 474/49;
474/50; 474/47 |
International
Class: |
F16H 055/30; F16H
059/00; F16H 055/52 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 24, 1998 |
JP |
H10-208972 |
Jul 27, 1999 |
JP |
H11-212024 |
Claims
What is claimed is:
1. A transmission comprising an endless transmitting member having
many engagement portions arranged at equal intervals in the
peripheral direction on the inner peripheral surface thereof and a
pair of rotating bodies around which the transmitting member
passes, in which the transmitting member winding portion of at
least one rotating body is formed by many movable members which are
arranged at intervals in the circumferential direction of the
rotating body and capable of moving in the radial direction of the
rotating body, and the diameter of the winding portion of the
rotating body is increased or decreased by moving the movable
members in the radial direction, wherein there is provided a
winding member with ends which is wound around the winding portion
of the rotating body from the outside, one end of which is fixed to
a predetermined movable member, the other end side of which is
inserted into the inside of the winding portion in an unfixed state
through between predetermined movable members, and which has many
engagement portions engaging with engagement portions of the
transmitting member on the outer peripheral surface, the movable
members are provided so as to move stepwise in the radial direction
of the rotating body so that the circumferential length of the
winding member at the winding portion changes in increments of the
predetermined number of the engagement portions, and when the
winding member and the transmitting member are engaged with each
other, bending points thereof come to almost the same
positions.
2. The transmission according to claim 1, wherein the rotating body
comprises a first side plate rotating integrally with the rotating
shaft of the rotating body, and a second side plate capable of
turning relative to the first side plate around the rotating shaft
of the rotating body, the first side plate is formed with many
elongated holes engaging movably with the movable member, and the
second side plate is formed with many elongated holes engaging
movably with the movable member and intersecting the elongated
holes of the first side plate.
3. The transmission according to claim 2, wherein the elongated
holes of the first side plate is formed straight in the radial
direction, and the elongated holes of the second side plate is
formed slantwise with respect to the elongated holes of the first
side plate.
4. The transmission according to claim 2 or 3, wherein there is
provided holding means capable of holding the first and second side
plates at a plurality of turning positions shifting stepwise in the
circumferential direction.
5. The transmission according to claim 4, wherein the holding means
is formed by a plurality of holes formed at intervals in the
circumferential direction of the rotating body on one side plate
side, and at least one protrusion provided on the other side plate
side so as to be capable of being inserted into an arbitrary hole
of one side plate.
6. The transmission according to claim 4, wherein the holding means
is formed by a plurality of grooves provided at intervals in the
circumferential direction of the rotating body in the elongated
holes of the second side plate and capable of engaging with the
movable members.
7. The transmission according to claim 2 or 3, further comprising:
a first turning member which is supported on the first side plate
so as to be movable in the axial direction, and rotates integrally
with the first side plate; a second turning member which is
provided rotatably with the rotation axis of the first side plate
being the center, and rotates integrally with the second side
plate; interlocking means for rotating the second turning member in
a predetermined direction with the rotation axis of the first side
plate being the center when the first turning member is moved in
the axial direction of the first side plate; and driving means for
moving the first turning member stepwise in the axial
direction.
8. The transmission according to claim 7, wherein the interlocking
means is formed by at least one groove provided in one turning
member so as to be slantwise with respect to the moving direction
of the first turning member, and at least one protrusion which is
provided on the other turning member and engages with the groove in
one turning member.
9. The transmission according to claim 1, 2, 3, 4, 5, 6, 7 or 8,
wherein a plurality of winding members are provided in the
circumferential direction of the rotating body, and the winding
members are arranged so as to be symmetrical with each other with
respect to the rotating shaft of the rotating body.
10. The transmission according to claim 1, 2, 3, 4, 5, 6, 7, 8 or
9, wherein a plurality of winding members are provided in the width
direction of the rotating body, and the winding members are
arranged so as to be symmetrical with each other with respect to
the rotating shaft of the rotating body.
11. The transmission according to claim 1, 2, 3, 4, 5, 6, 7 or 8,
wherein on one end side in the axial direction of the rotating
body, there is provided an auxiliary member with ends which has a
mass and a length equivalent to those of the winding member and
moves in the radial direction of the rotating body in synchronism
with the winding member, and the auxiliary member is arranged so as
to be symmetrical with the winding member with respect to the
rotating shaft of the rotating body.
12. The transmission according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9,
10 or 11, wherein the engagement portions of the transmitting
member are formed so as to project on the winding member side, many
grooves serving as engagement portions are formed on the outer
peripheral surface side of the winding member, many gaps located
between the grooves are provided on the inner peripheral surface
side of the winding member, and side walls having the bending
points are provided at both side portions in the width direction of
the winding member.
13. The transmission according to claim 12, wherein the winding
member is formed by many divided members, and the divided members
are connected to each other rotatably with the bending points being
a turning support points.
14. The transmission according to claim 12 or 13, wherein the
transmitting member is formed by many link members both ends of
which are connected to each other rotatably, the engagement
portions are formed with the turning support points of the link
member being the center, and a concave portion for accommodating a
portion between the grooves of the winding member is provided
between the turning support points of the link member.
15. The transmission according to claim 14, wherein the link member
is formed so that a part of the concave portion extends to a
portion beyond a straight line connecting the turning support
points of the link member.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a transmission used for
various machines requiring the transmission of power, such as
automobiles, bicycles, and other transportation machines.
[0003] 2. Description of the Related Art
[0004] Conventionally, there has been known a transmission
comprising an endless belt passing around a pulley, in which a belt
winding portion of the pulley is formed by many movable members
arranged at intervals in the circumferential direction, and the
movable members are moved in the radial direction, by which the
diameter of the belt winding portion of the pulley is changed, as
disclosed in Japanese Patent Laid-Open No. 62-75167, for
example.
[0005] However, like the above-described transmission, a
construction which transmits power by means of belt-to-pulley
contact has a problem in that the whole transmission is made large
when great power is transmitted because the transmission efficiency
of power is decreased by a slip of the belt, so that it is
difficult to practically use such a construction.
[0006] To solve this problem, for example, International
Publication No. WO93/07045, U.S. Pat. No. 5,049,113, and German
Patent No. 727593 have disclosed a transmission comprising a
winding member with ends which is wound around the movable members
of the pulley from the outside, wherein one end of the winding
member is fixed to a predetermined movable member, the other end of
the winding member is inserted into the inside of the pulley in an
unfixed state, and a transmitting member comprising a toothed belt
or a chain is engaged with the winding member. This configuration
has an advantage that a slip does not occur when power is
transmitted because the transmitting member is engaged with the
winding member. However, in such a configuration, because a bending
points of the winding member and bending points of the transmitting
member (for example, turning support points connecting components
of the chain) are away from each other in the radial or
circumferential direction of the pulley, the winding member and the
transmitting member are engaged with each other when the pulley has
a predetermined diameter, but when the diameter of the pulley
changes, the positions of the bending points of the winding member
and the bending points of the transmitting member shift in the
circumferential direction of the pulley, so that the winding member
and the transmitting member cannot be engaged with each other.
Therefore, it is impossible to practically use the conventional
construction as a transmission.
SUMMARY OF THE INVENTION
[0007] The present invention has been made to solve the above
problems, and accordingly an object thereof is to provide a
transmission capable of surely transmitting power even in a
configuration in which the diameter of a rotating body is
changed.
[0008] To attain the above object, the present invention provides a
transmission comprising an endless transmitting member having many
engagement portions arranged at equal intervals in the peripheral
direction on the inner peripheral surface thereof and a pair of
rotating bodies around which the transmitting member passes,
wherein the transmitting member winding portion of at least one
rotating body is formed by many movable members which are arranged
at intervals in the circumferential direction of the rotating body
and capable of moving in the radial direction of the rotating body,
and the diameter of the winding portion of the rotating body is
increased or decreased by moving the movable members in the radial
direction, characterized in that there is provided a winding member
with ends which is wound around the winding portion of the rotating
body from the outside, one end of which is fixed to a predetermined
movable member, the other end side of which is inserted into the
inside of the winding portion through between predetermined movable
members, and which has many engagement portions engaging with
engagement portions of the transmitting member on the outer
peripheral surface; the movable members are provided so as to move
stepwise in the radial direction of the rotating body so that the
circumferential length of the winding member at the winding portion
changes in increments of the predetermined number of the engagement
portions; and when the winding member and the transmitting member
are engaged with each other, bending points thereof come to almost
the same positions. Thereby, a rotational force is transmitted by
the engagement of the engagement portions of the transmitting
member with the engagement portions of the winding member, so that
power is transmitted without the occurrence of a slip between the
transmitting member and the winding member. Therefore, the power
transmitting efficiency can be enhanced, and the transmission body
can be made small. Also, when the movable members are moved in the
radial direction, the diameter of the winding member that is wound
around the movable members increases or decreases, so that the
speed reducing ratio with respect to the other rotating body
changes. That is to say, the circumferential length of the winding
member that is wound around the movable members is changed by
causing the other end side of the winding member to go in or out
through between the movable members. At this time, the
circumferential length of the winding member changes stepwise by
the predetermined number of the engagement portions of the winding
member, so that the engagement portions of the transmitting member
and the winding member are always engaged surely with each other at
any speed change position. At this time, when the winding member
and the transmitting member are engaged with each other, the
bending points thereof come to almost the same position, so that
the positions of the bending points of the winding member and the
transmitting member do not change relatively even if the diameter
of the winding portion of the rotating body is changed. Therefore,
even if the diameter of the rotating body is changed, the
engagement state of the winding member with the transmitting member
can be kept surely.
[0009] Also, according to the present invention, in the above
configuration, the rotating body comprises a first side plate
rotating integrally with the rotating shaft of the rotating body,
and a second side plate capable of turning relative to the first
side plate around the rotating shaft of the rotating body; the
first side plate is formed with many elongated holes engaging
movably with the movable member; and the second side plate is
formed with many elongated holes engaging movably with the movable
member and intersecting the elongated hole in the first side plate.
Thereby, by relatively turning the first and second side plates,
the diameter of the winding member that is wound around the movable
members is changed. Therefore, a reliable speed change operation
can be provided by a simple structure, which is very advantageous
in practical use. In this case, the elongated holes of the first
side plate are formed straight in the radial direction, and the
elongated holes of the second side plate are formed slantwise with
respect to the elongated hole in the first side plate. Thereby,
when the movable members are moved in the radial direction, a
relative rotational difference between the movable members and the
rotating body does not occur. Therefore, the tension of the
transmitting member does not change at the time of speed change,
and a stable speed change operation can always be performed.
[0010] Also, according to the present invention, in the above
configuration, a plurality of winding members are provided in the
circumferential direction or the width direction of the rotating
body, and the winding members are arranged so as to be symmetrical
with each other with respect to the rotating shaft of the rotating
body. Thereby, the center of gravity of the rotating body can
always be maintained on the rotating shaft thereof, and vibrations
caused by a positional shift between the center of rotation and the
center of gravity of the rotating body can surely be prevented from
occurring.
[0011] Also, according to the present invention, in the above
configuration, on one end side in the axial direction of the
rotating body, there is provided an auxiliary member with ends
which has a mass and a length equivalent to those of the winding
member and moves in the radial direction of the rotating body in
synchronism with the winding member, and the auxiliary member is
arranged so as to be symmetrical with the winding member with
respect to the rotating shaft of the rotating body. Thereby, the
center of gravity is displaced with respect to the rotating shaft
of the rotating body by the other end side of the winding member in
an unfixed state existing partially in the circumferential
direction. However, the auxiliary member having a mass and a length
equivalent to those of the winding member is arranged so as to be
symmetrical with the winding member, and moves in the radial
direction of the rotating body in synchronism with the winding
member, so that the displacement of the center of gravity of the
rotating body is corrected to the side of the rotating shaft
thereof, and vibrations caused by a positional shift between the
center of rotation and the center of gravity of the rotating body
can surely be prevented from occurring even when one winding member
is used.
[0012] Also, according to the present invention, in the above
configuration, the transmitting member is formed by many link
members both ends of which are connected to each other rotatably,
the engagement portions are formed with the turning support point
of the link member being the center, and a concave portion for
accommodating a portion between the engagement portions in the
winding member is provided between the turning support points of
the link member. In this case, the link member is formed so that a
part of the concave portion extends to a portion beyond a straight
line connecting the turning support points of the link member.
Thereby, when a tensile force is applied to the transmitting
member, the link member is subjected to elastic bending
deformation. Therefore, if a sudden driving force is applied to the
transmitting member, the shock can be absorbed, and the reduction
in noise and the improvement in durability can be achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a side sectional view of a transmission in
accordance with a first embodiment of the present invention;
[0014] FIG. 2 is a front sectional view of the transmission;
[0015] FIG. 3 is an enlarged sectional view of a principal portion
of the transmission;
[0016] FIGS. 4A and 4B are explanatory views for illustrating the
operation of a movable member and each of elongated holes;
[0017] FIG. 5 is a front view of a movable member for fixing a
belt;
[0018] FIG. 6 is a partially sectional view of a winding member and
the belt;
[0019] FIG. 7 is a partially sectional view of the winding member
and the belt;
[0020] FIG. 8 is a sectional view taken along a line I-I of FIG.
7;
[0021] FIG. 9 is a partial perspective view of the winding
member;
[0022] FIG. 10 is a partially sectional view of the winding member
and the belt, showing a bent state;
[0023] FIG. 11 is a schematic side view showing an example in which
a plurality of winding members are provided in the circumferential
direction of a pulley;
[0024] FIG. 12 is a sectional view of a principal portion showing
an example in which a plurality of winding members are provided in
the width direction of a pulley;
[0025] FIGS. 13A and 13B are enlarged views of a principal portion
showing a modification of the elongated hole;
[0026] FIG. 14 is a side sectional view of the transmission in
accordance with a second embodiment of the present invention;
[0027] FIG. 15 is a sectional view taken along a line II-II of FIG.
14;
[0028] FIG. 16 is a partially sectional view of a chain and the
winding member, showing a third embodiment of the present
invention;
[0029] FIG. 17 is a partially sectional view of the chain and the
winding member, showing an engagement state;
[0030] FIG. 18 is a side view of a link member;
[0031] FIG. 19 is a partially sectional view of the chain, showing
a fourth embodiment of the present invention; and
[0032] FIG. 20 is a partially exploded perspective view of the
winding member, showing a fifth embodiment of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] FIGS. 1 to 10 show a first embodiment of the present
invention. A transmission shown in these figures comprises a pulley
10 comprising a rotating body, a winding member 20 attached to the
pulley 10, an endless belt 30 serving as a transmitting member
passing around the pulley 10, and a variable mechanism 40 for
changing the diameter of the pulley 10. The pulley 10 is installed
to a pulley shaft 50.
[0034] The pulley 10 comprises a first side plate 11 rotating
integrally with the pulley shaft 50, a second side plate rotatable
relatively with respect to the first side plate 11 around the
pulley shaft 50, and many movable members 13 supported by the side
plates 11 and 12 so as to be movable in the radial direction of the
pulley 10. The first side plate 11 is formed into a shape of paired
flanges having a distance therebetween in the axial direction, and
is provided with many elongated holes 11a extending straight in the
radial direction, which are formed on the side face of the first
side plate 11 at equal intervals in the circumferential direction.
The second side plate 12 is formed into a shape of paired flanges
having a distance therebetween in the axial direction, and is
provided with many elongated holes 12a extending curvedly, which
are formed on the side face of the second side plate 12 at equal
intervals in the circumferential direction. Also, the second side
plate 12 is rotatably supported on the inside of the first side
plate 11, and the elongated holes 11a in the first side plate 11
and the elongated holes 12a in the second side plate 12 overlap
with each other so as to intersect each other. The movable members
13 are disposed on the inside of the second side plate 12, and each
both ends thereof is inserted in the elongated holes 11a and 12a of
the side plates 11 and 12. In this case, each end of the movable
member 13 is supported by an intersecting portion of the elongated
holes 11a and 12a overlapping with each other as shown in FIG. 4A.
When the side plates 11 and 12 turn relatively, the movable members
13 supported by an intersecting portion of the elongated holes 11a
and 12a moves in the radial direction of the pulley 10 as shown in
FIG. 4B.
[0035] The winding member 20 is formed longer than the
circumferential length of a belt winding portion of the pulley 10,
and is provided with many grooves 20a formed at equal intervals in
the lengthwise direction on the outer peripheral surface side of
the winding member 20, which serve as engagement portions. That is,
one end of the winding member 20 is fixed to one movable member
13', and the winding member 20 is wound on the outside of the
movable members 13 and the other end thereof is inserted into the
inside of the movable members 13 through between the movable member
13' and the adjacent movable member 13 in an unfixed state. In this
case, as shown in FIG. 3, the movable member 13' is joined to one
end portion of the winding member 20, and is formed so that the
other end of the winding member 20 pass through. Also, on the inner
peripheral surface side of the winding member 20, there are formed
many gaps 20b in a substantially V shape, which are located between
the grooves 20a. Further, at both side portions in the width
direction of the winding member 20, there are formed side walls 20c
extending higher than the upper end of the grooves 20a, and the
side wall 20c is bent at a bending point 20d located slightly above
the gap 20b.
[0036] The belt 30 comprises a well-known toothed belt having many
teeth 30a, which serve as engagement portions, formed on the inner
peripheral surface of the belt 30, and passes around the pulley 10
and the other pulley (drive side or driven side), not shown. In
this case, the teeth 30a of the belt 30 engages with the grooves
20a of the winding member 20.
[0037] The variable mechanism 40 is provided with a turning member
41 which turns integrally with the second side plate 12, and the
turning member 41 engages with the second side plate 12 so as to be
movable in the axial direction. A plurality of concave portions 41a
provided on the peripheral edge of the turning member 41 are
engaged with a plurality of convex portions 12b provided on the
second side plate 12, and the turning member 41 is urged toward the
side of the second side plate 12 by a spring 42 attached to the
side of the first side plate 11. Also, on one side surface of the
first side plate 11 are formed a plurality of holes 11c at
intervals in the circumferential direction, and the turning member
41 is provided with a protrusion 41a inserted into an arbitrary
hole 11c. That is, by moving the turning member 41 in the axial
direction of the pulley shaft 50 to draw the protrusion 41a from
the hole 11c, the connection between the side plates 11 and 12 is
released. In this state, the side plates 11 and 12 are turned
relatively, and an arbitrary hole 11c is aligned with the position
of the protrusion 41a and the protrusion 41a is inserted into that
hole 11c, by which the circumferential length of the winding member
20 that is wound around the movable members 13 is changed. In this
case, the intervals between the holes 11c in the circumferential
direction are set so that the circumferential length of the winding
member 20 changes stepwise by the predetermined number of the
grooves 20a. Reference character L in FIG. 3 denotes one interval
of the grooves 20a.
[0038] In the transmission configured as described above, when the
movable members 13 of the pulley 10 are moved in the radial
direction by the variable mechanism 40, the diameter of the winding
member 20 that is wound around the movable members 13 increases or
decreases, so that the speed reducing ratio with respect to the
other pulley, not shown, changes. That is, by causing the other end
side of the winding member 20 to go in or out through between the
movable members 13 and 13', the circumferential length of the
winding member 20 that is wound around the movable members 13 is
changed. At this time, since the circumferential length of the
winding member 20 changes stepwise by the predetermined number of
the grooves 20a of the winding member 20, the teeth 30a of the belt
30 are always engaged surely with the grooves 20a of the winding
member 20 even if the speed is changed. Also, as shown in FIGS. 7
and 8, when the belt 30 engages with the winding member 20, the
side walls 20c of the winding member 20 are located on both sides
of the belt 30, and the bending points 20d of the winding member 20
and bending points 30b of the belt 30 are located at almost the
same position. Thereupon, when the winding member 20 and the belt
30 are bent as shown in FIG. 10, the positions of the bending
points 20d and 30b of the winding member 20 and the belt 20 do not
change relatively, so that the belt 30 can always be engaged surely
with the winding member 20 even if the diameter of the pulley 10
changes. At this time, the bend of the winding member 20 is
absorbed by the gaps 20b.
[0039] As described above, according to the transmission of this
embodiment, in the construction in which the speed is changed by
changing the diameter of the pulley 10, the belt winding portion of
the pulley 10 is formed by the winding member 20 having many
grooves 20a, and a rotational force is transmitted by the belt 30
having many teeth 30a engaging with the grooves 20a. Therefore,
power can be transmitted efficiently by the engagement of the teeth
30a with the grooves 20a. In this case, one end of the winding
member 20 is fixed to the belt winding portion and the other end
thereof is inserted into the inside of the belt winding portion in
an unfixed state, by which the circumferential length of the
winding member 20 is changed, and the circumferential length of the
winding member 20 is changed stepwise by the predetermined number
of the grooves 20a. Therefore, the teeth 30a of the belt 30 can
always be engaged surely with the grooves 20a of the winding member
20 even if the speed is changed, and the speed change operation can
be achieved surely. Also, since the elongated holes 11a of the
first side plate 11 rotating integrally with the pulley shaft 50 is
formed straight in the radial direction, a relative rotational
difference between the movable members 13 and the pulley 10 does
not occur when the movable members 13 are moved in the radial
direction. Therefore, the tension of the belt 30 does not change at
the time of speed change, and a stable speed change operation can
always be performed.
[0040] Although only one pulley 10 has been shown in the above
embodiment, the other pulley, not shown, is also configured in the
same way as described above, and the diameters of the pulleys are
changed in the opposite direction, by which the speed change ratio
can be made great.
[0041] Also, although the belt winding portion of the pulley 10 has
been formed by one winding member 20 in the above embodiment, a
plurality of winding members 20' having a short and equal
circumferential length may be arranged in the circumferential
direction of the pulley 10 as shown in FIG. 11. Alternatively, a
plurality of winding members 20 and belts 30 may be arranged in the
width direction of the pulley 10 as shown in FIG. 12. In this case,
the winding members 20' shown in FIG. 11 or the winding members 20
shown in FIG. 12 are arranged symmetrically with each other
centering around the pulley shaft 50, by which the center of
gravity of the pulley 10 including the winding members 20 (or 20')
can be maintained on the rotating shaft thereof, so that vibrations
caused by a positional shift between the center of rotation and the
center of gravity can surely be prevented from occurring.
[0042] Further, although the winding member 20 has been bent at
bending points 20d by partial elastic deformation of the side walls
20c in the above embodiment, the winding member 20 may be formed by
many divided members that are divided at the gap 20b, and the
divided members may be connected rotatably to each other at the
bending point 20d.
[0043] Also, the circumferential length of the winding member 20
has been changed stepwise by forming the plurality of holes 11c in
the first side plate 11 and by engaging the protrusion 41a of the
turning member 41 with an arbitrary hole 11c in the above
embodiment, the elongated hole 12a of the second side plate 12 is
formed with a plurality of grooves 12c as shown in FIG. 13A, and
the movable member 13 is engaged with an arbitrary groove 12c as
shown in FIG. 13B, by which the movable member 13 may be positioned
stepwise.
[0044] FIGS. 14 and 15 show a second embodiment of the present
invention. Although the speed has been changed manually by means of
the variable mechanism 40 in the above embodiment, the speed is
changed automatically in this embodiment.
[0045] That is, a variable mechanism 60 shown in FIG. 14 comprises
a first turning member 61 turning integrally with the first side
plate 11, a second turning member 62 turning integrally with the
second side plate 12, and a driving mechanism 63 for driving the
first turning member 61. The first turning member 61 is engaged
with the first side plate 11 so as to be movable in the axial
direction, and at one end thereof are provided a plurality of
protrusions 61a engaging with the second turning member 62 at
intervals in the circumferential direction. The second turning
member 62 is engaged with the second side plate 12 so as to be
movable in the axial direction, and at one end thereof are provided
a plurality of grooves 62a engaging with the protrusions 61a of the
first turning member 61 at intervals in the circumferential
direction. That is, the groove 62a of the second turning member 62
is formed slantwise with respect to the axial direction of the
pulley shaft 50 as indicated by the chain line in FIG. 14.
Accordingly, when the first turning member 61 moves in the axial
direction, the second turning member 62 rotates around the pulley
shaft 50. In this case, the second turning member 62 is engaged
with convex portions 12b of the second side plate 12, and the
second turning member 62 is urged toward the side of the second
side plate 12 by a spring 64 attached to the side of the first side
plate 11. The driving mechanism 63 has a driving member 63b
rotatably attached to the first turning member 61 via a bearing
63a, and is configured so as to move the first turning member 61 in
the axial direction of the pulley shaft 50 via the driving member
63b. Although simplified in FIG. 14, the driving mechanism 63
comprises a well-known mechanism capable of controlling the
movement amount of the driven side, such as a hydraulic cylinder or
an actuator or the like. Therefore, by moving the first turning
member 61 stepwise by a predetermined amount, the circumferential
length of the winding member 20 that is wound around the movable
members 13 is changed by the predetermined number of the grooves
20a.
[0046] Also, the variable mechanism 60 is provided with an
auxiliary mechanism 70 on one end side in the axial direction of
the side plates 11 and 12. This auxiliary mechanism 70 comprises a
third side plate 71 rotating integrally with the first side plate
11, a fourth side plate 72 rotating integrally with the second side
plate 12, an auxiliary member 73 with ends which is attached to the
side plates 71 and 72 so as to be movable in the radial direction
of the pulley 10, and a guide member 74 with ends which extends
along the auxiliary member 73. The third side plate 71 is formed
into a shape of paired flanges having a distance therebetween in
the axial direction, and is provided with many elongated holes 71a
(partially shown in FIG. 15) extending curvedly, which are formed
on the side face of the third side plate 71 at equal intervals in
the circumferential direction. The fourth side plate 72 is formed
into a shape of paired flanges having a distance therebetween in
the axial direction, and is provided with many elongated holes 72a
(partially shown in FIG. 15) extending straight, which are formed
on the side face of the fourth side plate 72 at equal intervals in
the circumferential direction. In this case, the elongated holes
71a of the third side plate 71 and the elongated holes 72a of the
fourth side plate 72 overlap with each other so as to intersect
each other. The auxiliary member 73 is formed into a chain shape
having many rotating shafts 73a, and only the rotating shaft 73a on
one end side is inserted into the predetermined elongated holes 71a
and 72a. The guide member 74 is arranged on the outer periphery
side of the auxiliary member 73, and one end thereof is connected
to the rotating shaft 73a on one end side. Also, many pins 75
inserted into the elongated holes 71a and 72a are arranged on the
outer surface side of the guide member 74. That is, the rotating
shaft 73a on one end side of the auxiliary member 73 and the pins
75 are supported by an intersecting portion of the elongated holes
71a and 72a overlapping with each other, and move in the radial
direction of the pulley 10, like the movable members 13 between the
first and second side plates 11 and 12, when the side plates 71 and
72 turn relatively. Also, the other end sides of the auxiliary
member 73 and the guide member 74 are inserted into the inside of
the auxiliary member 73 in an unfixed state, like the winding
member 20. In this case, the auxiliary member 73 has a mass and a
length equivalent to those of the winding member 20, and one end
side (fixed end) and the other end side (free end) thereof are
arranged so as to be symmetrical with the winding member 20 with
respect to the pulley shaft 50.
[0047] In the above-described configuration, the second side plate
12 is turned stepwise with respect to the first side plate 11 by
the driving mechanism 63 of the variable mechanism 60, by which the
movable members 13 of the pulley 10 are moved in the radial
direction, so that the diameter of the winding member 20 is
changed. Also, in the pulley 10, the center of gravity is displaced
with respect to the center of rotation of the pulley shaft 50 by
the free end of the winding member 20 existing partially in the
circumferential direction. However, since the auxiliary member 73
of the auxiliary mechanism 70, which rotates integrally with the
pulley 10, is arranged symmetrically with the winding member 20,
the displacement of the center of gravity of the pulley 10 is
corrected to the side of the rotation axis of the pulley shaft 50.
Thereby, the center of gravity of the pulley 10 is always
maintained on the rotation axis of the pulley shaft 50, so that
vibrations caused by a positional shift between the center of
rotation and the center of gravity can surely be prevented from
occurring. Also, when the circumferential length of the winding
member 20 is changed by speed change, the circumferential length of
the auxiliary member 73 of the auxiliary mechanism 70 is changed in
synchronism with the winding member 20 by the radial movement of
the pins 75. Therefore, a balance between the winding member 20 and
the auxiliary member 73 can always be kept at any speed change
position.
[0048] Although a transmission having one winding member 20 has
been shown in the above embodiment, for example, as shown in FIG.
11, when a plurality of winding members 20' are provided in the
circumferential direction of the pulley 10, or as shown in FIG. 12,
when a plurality of winding members 20 provided in the width
direction of the pulley 10, the center of gravity of the pulley 10
including the winding members 20 (or 20') can be maintained on the
rotating shaft thereof as described above, so that the auxiliary
mechanism 70 in the second embodiment can be omitted.
[0049] FIGS. 16 to 18 show a third embodiment of the present
invention, showing another mode of the transmitting member and the
winding member.
[0050] That is, a chain 31 serving as a transmitting member shown
in the figures comprises many link members 31b rotatably connected
to each other via connecting pins 31a. On both end sides of the
link member 31b are formed a substantially semicircular engagement
portions 31d with a turning support points 31c (bending points) of
the connecting pins 31a being the center. Also, a concave portion
31e continuous with the engagement portions 31d is provided between
the engagement portions 31d, and the link member 31b is formed so
that the upper end side in the figure is curved upward along the
concave portion 31e.
[0051] Also, a winding member 21 shown in the figures has many
grooves 21a engaging with the engagement portions 31d of the chain
31 on the outer peripheral surface side, and is provided with many
substantially V-shaped gaps 21b each located in the center of the
groove 21a on the inner peripheral surface side. That is, a part of
the grooves 21a is divided in the circumferential length direction
of the winding member 21 by the gaps 21b. Also, side walls 21c are
formed at both side portions in the width direction of the winding
member 21, and a portion between the grooves 21a is formed higher
than the top end of the side walls 21c. In this case, the side
walls 21c are bent at a bending points 21d located slightly above
the gaps 21b. That is, when the chain 31 engages with the winding
member 21, as shown in FIG. 17, the portions between the grooves
21a of the winding member 21 is accommodated by the concave portion
31e of the link members 31b, and the bending points 21d of the
winding member 21 and the turning support points 31c, serving as a
bending point, of the chain 31 come to the same positions.
Therefore, like the first embodiment, when the winding member 21
and the chain 31 are bent, the positions of bending points of the
winding member 21 and the chain 31 do not change relatively, so
that the winding member 21 and the chain 31 can always be engaged
surely with each other even if the diameter of the pulley 10
changes.
[0052] Also, in the link member 31b of the chain 31, as shown in
FIG. 18, a part of the concave portion 31e is formed so as to
extend to a portion (hatched portion in the figure) beyond a
straight line connecting the turning support points 31c of the link
member 31b. Thereupon, when a tensile force is applied to the chain
31, the link member 31b is subjected to elastic bending deformation
in the direction of the solid-line arrow mark in the figure with a
curved portion 31f not including the straight line connecting the
turning support points 31c being the center. Therefore, if a sudden
driving force is applied to the chain 31, the shock can be absorbed
by the aforementioned bending deformation of the link member
31b.
[0053] FIG. 19 shows a fourth embodiment of the present invention,
showing another mode of the transmitting member. In this
embodiment, the chain 31 of the third embodiment is provided with
many rollers 32 serving as engagement portions. That is, the
rollers 32 are rotatably fitted to the connecting pins 31a of the
chain 31, and the outer peripheral face thereof is formed slightly
larger than the peripheral edge of the link member 31b so as to be
in contact with the winding member side.
[0054] FIG. 20 shows a fifth embodiment of the present invention,
showing another mode of the winding member. That is, a winding
member 22 shown in this figure comprises two kinds of divided
members 23 and 24, and although not shown, the divided members 23
and 24 are connected in large numbers alternately. One divided
member 23 has a pair of side walls 23a provided at both side
portions in the width direction, and between the side walls 23a,
divided grooves 23b, which are divided into two in the direction in
which the divided members 23 and 24 are connected, are provided on
one end side and the other end side in that direction. Also, on the
side surface of the side walls 23a, there are provided a pair of
connecting shafts 23c projecting in the width direction. The other
divided member 24 has a pair of side walls 24a provided at both
side portions in the width direction, and between the side wall
portions 24a, divided grooves 24b, which are divided into two in
the direction in which the divided members 23 and 24 are connected,
are provided on one end side and the other end side in that
direction. Also, the side walls 24a are formed with a pair of holes
24c penetrating in the width direction. Thus, the divided members
23 and 24 are rotatably connected to each other by the fitting of
the connecting shaft 23c into the hole 24c. In this case, an
engagement portion with the transmitting member is formed by the
divided grooves 23b and 24b of the divided members 23 and 24.
[0055] Further, although one divided member 23 has been provided
with the integrally projecting connecting shafts 23c, which is
inserted into the holes 24c of the divided member 24, in the
above-described embodiment, one divided member 23 may be provided
with holes equal to the holes in the other divided member 24 so
that a connecting shafts, which is a separate component, is
inserted into these holes.
* * * * *