Title of Invention

A CLUTCH RELEASE MECHANISM

Abstract A clutch release mechanism includes a movable cam plate 20 rotatably connected to a release plate 16, a regulating bolt 23 supported on the side cover 24, a ball holder 22 threadedly fitted over the bolt 23 and disposed in an opposed relation to the movable cam plate 20, and balls 30 retained rotatably and non-removably in ball retaining bores 29 in the ball holder 22 and engaged at their tops in cam recesses 31 in the movable cam plate 20. Thus, when the clutch release mechanism is in an inoperative state, the balls can be left idle to ensure an ON state of the clutch, while the vibration of the balls can be inhibited- Moreover, the clutch release mechanism is constructed of a reduced number of parts, and is good in assemblability.
Full Text CLUTCH RELEASE MECHANISM
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a clutch release
mechanism using a ball cam for bringing a clutch in a power unit of a motorcycle or a buggy into an OFF state.
DESCRIPTION QF THE RELATED ART
Such a conventional clutch release mechanism is designed , as disclosed, for example, in Japanese Utility Model Publication No.Hei5-45852 such that a ball is interposed between a stationary cam plate and a movable cam plate which are opposed to each other, so that a clutch is brought into an OFF state by urging a release plate of a clutch with a thrust force generated by the relative turning movement of the cam plates.
When the clutch release mechanism is inoperative, small gaps are generally required to be provided between the stationary cam plate and the ball and between the ball and the movable cam plate, thereby leaving the ball idle, in order to ensure the ON state of the clutch.
In the above conventional arrangement, however, if the ball is left idle between the stationary cam plate and the movable cam plate, the ball may be vibrated during operation of an engine to generate a noise in some cases. The stationary cam plate, the ball and the movable cam plate are parts

independent of one another, respectively and for this reason, the number of parts is large, and it is not easy to say that the clutch release mechanism is good in assemblability. SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a clutch release mechanism, wherein when the clutch release mechanism is inoperative, the vibration of the ball can be inhibited, even if the ball is left idle to ensure the ON state of the clutch, and the number of parts is small, leading to a good assemblability of the clutch release mechanism.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided a clutch release mechanism comprising a movable cam plate rotatably connected to a release plate of a clutch with a release bearing interposed therebetween, a regulating bolt supported on a stationary structure coaxially with the movable cam plate, a ball holder threadedly fitted over the regulating bolt and disposed in an opposed relation to the movable cam plate, and balls retained rotatably and non-removably in a circumferential arrangement in the ball holder and engaged at tops thereof respectively in a plurality of cam recesses arranged in a circumferential direction of the movable cam plate.
With the first feature, even if gaps are provided between bottom surfaces of the cam recesses in the movable ceon plate and the balls in the ball holder in order to ensure the ON state of the clutch, the balls are retained in the ball holder fixed

on the regulating bolt. Therefore, the vibration of the balls can be inhibited to prevent a noise and provide an enhancement in durability. Moreover, the balls and the ball holder retaining the balls constitute a single part and moreover, the ball holder also serves as a conventional stationary cam plate, leading to a reduced number of parts, a good assemblability and a reduction in cost.
According to a second aspect and feature of the present invention, in addition to the first feature, the ball holder has spherical ball retaining bores provided therein to rotatably accommodate the balls, each of said bores having an opening which is throttled to inhibit the removal of each of the balls out of the bore.
With the second feature, the ball retaining structure can be made into a simple construction.
According to a third aspect and feature of the present invention, in addition to the first feature, the ball holder is comprised of a boss threadedly fitted over the regulating bolt, a holder plate coupled by caulking to one end of the boss, and a retainer superposed on one side of the holder plate and clamped between the holder plate and the boss, and wherein the holder plate and the retainer are provided with tapered, ball retaining bores to which each of the balls is retained by cooperation of the bores, so that the ball can be rotated, but cannot be removed out of the bores.
With the third feature, various portions of the ball

holder can be made by pressing, which can contribute to a further reduction in cost.
The above and other objects, features and advantages of the invention will become apparent from the following description of the preferred embodiments taken in conjunction
*
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figs.l to 4 show a first embodiment of the present invention, wherein
Fig.l is a vertical cross-sectional view of a clutch for a motorcycle and portions around the clutch;
Fig. 2 is a sectional view taken along a line 2-2 in Fig. 1;
Fig. 3A is a sectional view taken along a line 3-3 in Fig. 1 ;
Fig.3B is a view similar to Fig.3A, explaining an operation;
Fig. 4 is an exploded view of an essential portion of a release mechanism;
Fig. 5 is a sectional view of an essential portion of a release mechanism according to a second embodiment of tlie present invention; and
Fig.6 is a vertical cross-sectional view of an essential portion of a release mechanism according to a third embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be described by way of embodiments with reference to the accompanying drawings.

First of all, a first embodiment of the present invention shown in Figs. 1 to 4 will be described. Referring to Fig.l, a crankshaft 2 and an input shaft 3 of a transmission disposed in parallel to the crankshaft 2 are rotatably carried on a casing 1 of a power unit in a motorcycle with ball bearings 4 and 5 interposed therebetween, respectively. The shafts 2 and 3 are connected to each other through a primary reduction device 6 and a clutch 7.
The clutch 7 includes a bottomed cylindrical clutch outer 8 rotatably carried on the input shaft 3. A large-diameter driven gear 6b is mounted to an outer surface of an end wall 8a of the clutch outer 8 and meshed with a small-diameter driving gear 6a which is fixedly mounted on the crankshaft 2. The primary reduction device 6 is constituted by the driving gear 6a and the driven gear 6b.
A cylindrical clutch inner 10 is spline-coupled and secured to the input shaft 3 by a nut 9 and disposed in the clutch outer 8 . A plurality of driving friction plates 11 are slidably spline-engaged with a peripheral surface of the clutch inner 10, and a plurality of driven friction plates 12 are slidably spline-engaged with a peripheral wall of the clutch outer 8. The driving and driven friction plates 11 and 12 are superposed alternately on one another.
A pressure receiving plate 13 is integrally connected to the clutch inner 10 and disposed in an opposed relation to the driving friction plate 11 disposed at an outermost location in

the group of the friction plates 11 and 12. A pressing plate
14 is slidably carried on an outer peripheral surface of a boss
10a of the clutch inner 10 and disposed in an opposed relation

to the driving friction plate 11 disposed at an innermost location in the group of the friction plates 11 and 12.

The pressing plate 14 has a plurality of supporting bosses
15 (only one of which is shown in Fig.l) integrally projectingly
provided on one side thereof to extend through an end wall of
the clutch inner 10, and a release plate 16 is secured to top
ends of the supporting bosses 15 by a bolt 17. A clutch spring
18 is mounted under compression between the release plate 16
and an end plate 10b of the clutch inner 10.
A short shaft 20a secured to a central portion of a movable cam plate 20 is rotatably mounted to a central portion of the release plate 16 with a release bearing 21 interposed therebetween, and a ball holder 22 opposed to the movable cam plate 20 is threadedly fitted over a regulating bolt 23 which is arranged coaxially with the input shaft 3. The regulating bolt 23 is secured to a side cover 24 (a stationary structure) coupled to the casing 1 by (1) a flange 23a integrally formed on the bolt 23 and (2) a nut 25 threadedly fitted over the bolt 23. A pin 27 is fixedly mounted in the ball holder 22 for preventing the rotation of the ball holder 22 and slidably fitted in a retaining bore 26 in the side cover 24.
As shown in Fig. 2, a plurality of (three in the illustrated embodiment) spherical ball-retaining bores 29 are

defined in the surface of the ball holder 22 which is opposed to the movable cam plate 20, and they are arranged at equal distances in a circumferential direction. Balls 30 are retained rotatably and non-removably in the ball-retaining bores 29.
As shown in Fig.4, the spherical retaining bores 29 are formed slightly more deeply than a hemisphere. The balls 30 are inserted into the retaining bores 29 and then, openings 29a in the ball retaining bores 29 are throttled by caulking, thereby inhibiting the balls 30 from being removed out of the ball retaining bores 29-
On the other hand, earn recesses 31 far shallower than the ball retaining bores 29 are defined in the movable cam plate 20 at locations corresponding to the balls 30 , as shown in Fig. 3A, and top portions of the balls 30 exposed from the ball retaining bores 29 are engaged in the recesses 31.
A fork-shaped driven arm 32 is integrally formed on the movable cam plate 20 to extend in a radial direction of the movable cam plate 20. A tip end of a clutch arm 33 secured fo one end of a change spindle 34 is engaged with a fork portion of the driven arm 32. A roller 33a is pinned at the tip end of the clutch arm 33, so that the driven arm 32 can be smoothly turned from the clutch arm 33. The change spindle 34 is supported in parallel to the input shaft 3 by the casing 1 and the side cover 24, so that it is turned by a change pedal which is not shown.

The operation of the first embodiment will now be described.
When the balls 30 in the stationary ball holder 22 are staying in the cam recesses 31 in the movable cam plate 20, as shown in Fig.3A, the pressing plate 14 urges the group of the friction plates 11 and 12 against the pressure receiving plate 13 by a resilient force of the clutch spring 18 to bring the driving friction plates 11 and the driven friction plates 12 into frictional engagement with one another, thereby bringing the clutch 7 into an ON state. Thus, power of the engine is transmitted from the crankshaft 2 through the primary reduction device 6 and the clutch 7 to the input shaft 3 and further via another transmission element to a rear wheel to drive the rear wheel.
In the ON state of the clutch 7, a small gap g is provided between a bottom surface of each of the cam recesses 31 and a top surface of corresponding one of the balls 30 in order to ensure the frictional engagement of the driving friction plates 11 and the driven friction plates 12 with one another. Tfie regulation of the gap g can be achieved by loosing the nut 25 to rotate the ball 30 through an appropriate angle in a rightward or leftward direction, thereby advancing or retracting the ball holder 22 with respect to the movable cam plate 20.
Since the balls 30 are retained non-removably in the ball retaining bores 29 in the ball holder 22 supported on the regulating bolt 23, they cannot be vibrated, regardless of the

presence of the gaps g. This can contribute to the prevention of a noise and to an enhancement in durability.
When the change spindle 34 is now turned by turning the

change pedal (not shown) to conduct the gear shifting, the movable cam plate 20 is first turned by the clutch arm 33 turned

along with the change spindle 34. Then, each of the balls 30 in the stationary ball holder 22 smoothly climbs up a slope of the corresponding cam recess 31 in the movable cam plate 20, while being rolled, as shown in Fig. 3B, thereby urging the movable cam plate 20, and hence, the movable cam plate 20 urges the release plate 16 through the release bearing 21. As a result, the release plate 16 retracts the pressing plate 14, while compressing the clutch spring 18, and hence, the frictional engagement of the driving friction plates 11 and the driven friction plates 12 is released. Thus, the clutch 7 can be brought lightly into an OFF state to cut off the transmission of the power from the crankshaft 2 to the input shaft 3.
When the turning of the change spindle 34 is further advanced, a change mechanism (not shown) is operated with the OFF state of the clutch 7 being maintained. Therefore, the shifting of the transmission can be conducted smoothly.
If the change spindle 34 is returned to an original position after the shifting, the movable cam plate 20 is also returned to an original position. Therefore, the pressing plate 14 is advanced by the resilient force of the clutch spring 18 to urge the group of the friction plates 11 and 12 against

the pressure receiving plate 13 and to push back the release plate 16, thereby restoring the balls 30 in the cam recesses 31. Thus, the clutch 7 can be restored to the ON state.
The balls 30 and the ball holder 22 retaining the balls 30 constitute a single part and moreover, the ball holder 22 also serves as a conventional stationary cam plate. This can provide a reduction in number of parts and an enhancement in assemblability to contribute to a reduction in cost.
A second embodiment of the present invention will now be described with reference to Fig.5.
In the second embodiment, the openings 29a of the ball retaining bores 29 in the ball holder 22 are previously throttled, so that the balls 30 are inserted into the ball retaining bores 29, respectively, while resiliently widening the openings 29a. The other arrangement is similar to that in the previous embodiment and hence, the portions or components corresponding to those in the previous embodiment are designated by like reference characters in Fig.5, and the description of them is omitted.
A third embodiment of the present invention will now be described with reference to Fig.6.
In the third embodiment, a ball holder 22 comprises a boss
40 threadedly fitted over the regulating bold 23, a holder plate
41 coupled by caulking to one end 40a of the boss 40,-and a
retainer 42 superposed on a side face of the holder plate 41
on the side of the movable cam plate 20 and clamped between the

holder plate 41 and the boss 40. The holder plate 41 and the retainer 42 are provided with tapered ball-retaining bores 43 and 44, respectively, which are reduced in diameter toward the outside and retain the ball 30 by cooperation with each other, so that the ball 30 can be rotated, but cannot be removed out of the bores 43 and 44,
To fabricate the ball holder 22, the retainer 42 is first superposed on the holder plate 41, while inserting the ball 30 into the ball retaining bores 43 and 44. Then, the retainer 42 and the holder plate 41 are fitted over the boss 40, and their ends are caulked.
The other arrangement is similar to that in the first embodiment and hence, portions or components corresponding to those in the first embodiment are designated by like reference characters in Fig. 6, and the description of them is omitted.
According to the third embodiment, an effect similar to that in the first embodiment can be achieved, and it is easy to form members forming the ball holder 22 by pressing. Therefore, it is possible to provide the ball holder 22 at a comparatively low cost.
The present invention is not limited to the above-described embodiments, and various modifications in design may be made without departing from the spirit and scope of the invention defined in claims.






1. A clutch release mechanism comprising a movable cam plate
(20) rotatably connected to a release plate (16) of a clutch
(7) with a release bearing (21) interposed therebetween, a
regulating bolt (23) supported on a stationary structure (24)
coaxially with said movable cam plate (20) , a ball holder (22)
threadedly fitted over said regulating bolt (23) and disposed
in an opposed relation to said movable cam plate (20) , and balls
(30) retained rotatably and non-removably in a circumferential
arrangement in said ball holder (22) and engaged at tops thereof
respectively in a plurality of cam recesses (31) arranged in
a circumferential direction of said movable cam plate (20).
2. A clutch release mechanism according to claim 1. wherein said
ball holder (22) has spherical ball retaining bores (29)
provided therein to rotatably accommodate said balls (30 ) , each
of said bores having an opening (29a) which is throttled to
inhibit the removal of each of said balls (30) out of said bore
(29).
3 . A clutch release mechanism according to claim 1, wherein said ball holder (22) is comprised of a boss (40) threadedly fitted over said regulating bolt (23) , a holder plate (41) coupled by caulking to one end of said boss (40), and a retainer (42) superposed on one side of said holder plate (41) and clamped between said holder plate (41) and said boss (40) , and wherein said holder plate (41) and said retainer (42) are provided with tapered, ball retaining bores (43 and 44) to which each of said

balls (30) is retained by cooperation of the bores, so that said ball (30) can be rotated, but cannot be removed out of said bores (43 and 44).
4. A clutch release mechanism substantially as herein described with reference to the accompany drawings.


Documents:

062-mas-2000-abstract.pdf

062-mas-2000-claims filed.pdf

062-mas-2000-claims granted.pdf

062-mas-2000-correspondnece-others.pdf

062-mas-2000-correspondnece-po.pdf

062-mas-2000-description(complete) filed.pdf

062-mas-2000-description(complete) granted.pdf

062-mas-2000-drawings.pdf

062-mas-2000-form 1.pdf

062-mas-2000-form 26.pdf

062-mas-2000-form 3.pdf

062-mas-2000-form 5.pdf

062-mas-2000-other documents.pdf


Patent Number 198884
Indian Patent Application Number 62/MAS/2000
PG Journal Number 23/2006
Publication Date 09-Jun-2006
Grant Date 01-Mar-2006
Date of Filing 25-Jan-2000
Name of Patentee HONDA GIKEN KOGYO KABUSHIKI KAISHA
Applicant Address 1-1 MINAMI-AOYAMA 2-CHOME, MINATO-KU, TOKYO
Inventors:
# Inventor's Name Inventor's Address
1 TOSHIHARU AKUTSU C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO 4-1 CHUO 1 CHOME, WAKO-SHI, SAITAMA
2 YASUHIRO HIGASHI C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO 4-1 CHUO 1 CHOME, WAKO-SHI, SAITAMA
3 AKIRA SHIGIHARA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO 4-1 CHUO 1 CHOME, WAKO-SHI, SAITAMA
4 YOSHINOBU SAWAMURA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO 4-1 CHUO 1 CHOME, WAKO-SHI, SAITAMA
5 MASAHIRO 11 OF 47, YOKOE, TATEYAMA-MACHI, NAKANIIKAWA-GUN, TOYAMA
6 YASUMORI YAMASHITA 948 FUJINOKI, TOYAMA-SHI, TOYAMA
PCT International Classification Number F16D23/12
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 11-24234 1999-02-01 Japan