192 clutches and power-stop control – Clutches – Automatic
Reexamination Certificate
2000-06-15
2002-03-12
Lorence, Richard M. (Department: 3681)
192 clutches and power-stop control
Clutches
Automatic
C192S035000
Reexamination Certificate
active
06354414
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a clutch mechanism and, more particularly to a friction clutch mechanism wherein a driving member is coupled to a driven member using clutch pins and the clutch is switched on and off utilizing a frictional force of a friction plate.
2. Description of the Related Art
A clutch mechanism is a mechanical device for selectively connecting a driving member and a driven member, and various types, such as a friction clutch type, are used. Among these, there are those wherein when the driving member is rotated, the driving and driven members are coupled so that power can be transmitted from the driving member to the driven member, and when the driving member is stopped, the driving and driven members are uncoupled so that the driven member can rotate in both directions. This kind of clutch mechanism includes for example the “Free Wheel Clutch and Apparatus Using Same” disclosed in U.S. Pat. No. 4,909,365. The main features of this clutch mechanism are illustrated in
FIG. 23
hereof.
The related art clutch mechanism
300
shown in
FIG. 23
has an output shaft
302
, which is a driving member, rotatably supported by a housing
301
. The output shaft
302
projects outward from the housing
301
. A friction plate
303
and a pinion
304
, which is a driven member, are rotatably supported on the projecting part of the output shaft
302
. In this clutch mechanism
300
, a side face
305
of the friction plate
303
is pressed against a wall face
306
of the housing
301
with a predetermined force (thrust) F
2
, and the output shaft
302
and the pinion
304
are selectively coupled by the behavior of a clutch key
307
with respect to the output shaft
302
and the friction plate
303
and the pinion
304
.
More specifically, in the clutch mechanism
300
, a snap ring
308
is fitted to the end of the output shaft
302
projecting from the housing
301
, a compression spring
309
is interposed between the snap ring
308
and the pinion
304
, and by way of the pinion
304
the spring force of the compression spring
309
presses the side face
305
of the friction plate
303
against the wall face
306
of the housing
301
. Also, a leg part
311
of the clutch key
307
is so fitted in the friction plate
303
that it can swing through a predetermined angle.
When the output shaft
302
rotate s, utilizing a frictional force arising between the housing
301
and the friction plate
303
, the rotational timing of the friction plate
303
with respect to the output shaft
302
is delayed. As a result, the clutch key
307
swings in the front-rear direction of the drawing and couples the output shaft
302
with the pinion
304
, enabling power to be transmitted between the two.
When the rotation of the output shaft
302
stops, the clutch key
307
uncouples the output shaft
302
from the pinion
304
and thereby renders the pinion n
304
rotatable in both directions.
However, this clutch mechanism of related art has had the following four problems:
Firstly, because the clutch mechanism
300
utilizes a frictional force between the housing
301
and the friction plate
303
, to maintain a stable frictional force over a long period, it is necessary to consider wear of the contacting parts. In particular, when the output shaft
302
is to rotate at high speed, countermeasures to wear are even more important. And furthermore, because the contacting part of the friction plate
303
is exposed, the effect of dust and the like on its resistance to wear must be considered.
Secondly, because the clutch mechanism utilizes a frictional force obtained by pressing flat faces together, and the friction plate
303
having one of the flat faces rotates, to secure the frictional force it is necessary for the flatness and the assembly accuracy of the housing
301
and the friction plate
303
to be kept very high, and the dimensional management required is not easy.
Thirdly, because the clutch key
307
, which has a complex shape, is swingably fitted in respective key grooves of the output shaft
302
, the friction plate
303
and the pinion
304
to effect the clutch-ON operation, the structure of the clutch mechanism
300
is complex. Furthermore, the dimensional management of the key grooves and the clutch key
307
is not easy. Consequently, it is necessary for ample care to be taken always to engage the clutch mechanism
300
smoothly.
Fourthly, because the frictional force is produced by means of the spring force of a compression spring
309
fitted on the output shaft
302
, the clutch mechanism
300
is large in the length direction of the output shaft
302
.
SUMMARY OF THE INVENTION
It is therefore a first object of the present invention to provide a clutch mechanism wherein the frictional force between the housing side and the friction plate is stable.
It is a second o object of the invention to provide a clutch mechanism which is small and simple in construction, the dimensional management of which is easy, and which can always be engaged smoothly.
To achieve these and other objects, a first aspect of the invention provides a clutch mechanism comprising: a housing; a driving member, rotatably support ed by the housing a and having a plurality of cam grooves formed in an outer circumferential face thereof and extending in an axial direction thereof; a driven member, which can rotate coupled to the driving member and rotate freely uncoupled from the driving member; a disc-shaped friction plate, rotatably supported by the driving member and having in an inner circumferential face thereof a plurality of pin-holding grooves, facing the cam grooves and having their depths in a radial direction of the friction plate; tapered space parts, each formed by frictional engagement faces consisting of a bottom face of a respective cam groove and an inner circumferential face of the driven member; a plurality of clutch pins, each disposed partly in a tapered space part and partly between the cam groove forming that tapered space part and the pin-holding groove facing that cam groove; and an oil seal, interposed between an inner circumferential surface of the housing and an outer circumferential surface of the friction plate, for providing an action force tending to prevent the friction plate and, by extension, the clutch pins from moving; and a lubricant, filling a space enclosed by the housing, the friction plate and the oil seal, wherein when the driving member rotates, utilizing a frictional force on the friction plate, the clutch pins are engaged with the frictional engagement faces of the tapered space parts by a wedge action and the driving member and the driven member are thereby coupled so that power can be transmitted between them, and when the driving member stops, the driving member and the driven member cease to be coupled by the clutch pins and the driven member assumes an idling state with respect to the driving member.
Thus, in this invention, a friction plate is disposed in a housing, an oil seal is interposed between an inner circumferential surface of the housing and the outer circumferential surface of the friction plate, and the oil seal provides and action force tending to prevent the clutch pins from moving. That is, to produce a frictional force between the housing side and the friction plate, instead of a thrust force being made to act on the friction plate as in the related art, a radial force is applied. And because the frictional force is produced by an oil seal being fitted in contact with the outer circumferential surface of the friction plate and made to apply a contact force to the friction plate, the radius at which the frictional force acts can be made large. Accordingly, since a smaller frictional force is sufficient to provide the same frictional torque as in the related art described above, the contact pressure can be lowered and wear can be suppressed. As a result, the frictional force can be kept stable at all times. Furthermore, since the force providing the frictional torque acts in the r
Miyahara Kazuyoshi
Sueshige Hiroshi
Lorence Richard M.
Rodríguez Saúl
LandOfFree
Clutch mechanism does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Clutch mechanism, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Clutch mechanism will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2871038