Clutch device for motorcycle

A clutch device for a motorcycle includes a body, at least two centrifugal weights pivotably mounted on a side of the body, and at least two springs. Each centrifugal weight includes a through-hole extending from an inner side thereof through the outer periphery face thereof. A spring-attaching member is mounted in the through-hole of each centrifugal weight and includes a first end and a second end that has a screw hole. An adjusting screw is mounted in each spring-attaching member. Each spring includes a first end attached to an associated centrifugal weight and a second end attached to the first end of the spring-attaching member on another centrifugal weight. Each spring-attaching member moves along a longitudinal direction of an associated through-hole when an associated adjusting screw is turned, thereby adjusting tightness of an associated spring.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a clutch device. More particularly, the present invention relates to a clutch device for a motorcycle.

2. Description of the Related Art

Motorcycles with continuously variable transmission are popular nowadays. A clutch for a typical continuously variable transmission device comprises three centrifugal weights that are coupled together via three springs. When the centrifugal weights move under the action of centrifugal force, the springs stretch and then to their original positions, thereby changing the speed and the torque of the motorcycle. However, the clutch is an isolated structure such that the whole clutch must be detached for replacement in a case that fatigue or breakage of one or more springs occurs, resulting in inconvenient maintenance. Further, a worker could not directly proceed with adjustment of slackened springs (which slackening often occurs after a period of time of use) without dismantling the clutch while there is no scale or reference for such an adjustment. In other words, the worker has to adjust the springs based on personal experience such that the adjustment result is unsatisfactory and that the motorcycle could not obtain the initial speed and torque. Further, the conventional clutch is liable to deform or malfunction after a period of time, for the conventional clutch is not strong enough to withstand the change in the torque during the centrifugal movement of the centrifugal weights for the purposes of altering the speed and torque of the motorcycle.

SUMMARY OF THE INVENTION

A clutch device for a motorcycle in accordance with the present invention comprises a body, at least two centrifugal weights pivotably mounted on a side of the body, and at least two springs. Each centrifugal weight comprises a clutch plate on an outer periphery face thereof. Each centrifugal weight further comprises a through-hole extending from an inner side thereof through the outer periphery face thereof.

A spring-attaching member is mounted in the through-hole of each centrifugal weight and comprises a first end and a second end that has a screw hole. An adjusting screw is mounted in each spring-attaching member. Each spring comprises a first end attached to an associated centrifugal weight and a second end attached to the first end of the spring-attaching member on another centrifugal weight.

Each spring-attaching member moves along a longitudinal direction of an associated through-hole when an associated adjusting screw is turned, thereby adjusting tightness of an associated spring.

Preferably, each spring-attaching member comprises a scale on an outer periphery thereof, and the body comprises a plurality of openings respectively aligned with the scales of the spring-attaching members. This allows the user to precisely adjust the tightness of the springs.

Preferably, each opening of the body extends along a longitudinal direction of an associated spring to allow removal and replacement of the associated spring via the opening.

Preferably, the through-hole of each centrifugal weight comprises a shoulder portion, and each adjusting screw comprises an enlarged head that abuts against the shoulder portion of the through-hole of an associated centrifugal weight.

Preferably, a fixing ring is fixed to the other side of the body to improve the strength of the body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring toFIG. 1, a clutch device for a motorcycle in accordance with the present invention comprises a body1and at least two centrifugal weights11(three in this embodiment) pivotably mounted on a side of the body1. A clutch plate12is mounted on an outer peripheral face of each centrifugal weight11. Further, a spring13is mounted to an inner side of each centrifugal weight11.

Each centrifugal weight11comprises a through-hole111extending from the inner side thereof through the peripheral face thereof. Provided on an end of each centrifugal weight11is a hooking portion15to which an end of an associated spring13is attached. An axle161is mounted in a pivotal hole16in the end of each centrifugal weight11and comprises a screw hole162. The body1comprises a plurality of through-holes17each of which is aligned with the screw hole162of the axle161on an associated centrifugal weight11, with a screw18extending through each through-hole17into the screw hole162of the axle161on an associated centrifugal weight11. Thus, the axles161are fixed on the body1, and the centrifugal weights11are pivotable about the respective axles161.

The clutch device further comprises an adjusting unit2mounted in the through-hole111of each centrifugal weight11. Each adjusting unit2comprises a spring-attaching member21and an adjusting screw22. An end of the spring-attaching member21is attached to the other end of an associated spring13, and a screw hole211is defined in the other end of the spring-attaching member21. The adjusting screw22is mounted in the screw hole211of the spring-attaching member21such that rotation of the adjusting screw22causes the spring-attaching member21to move along a longitudinal direction of the through-hole111of the associated centrifugal weight11. The spring-attaching member21comprises a scale212on an outer periphery thereof to provide an indication of the extent of adjustment so that a worker may proceed with precise adjustment of each spring13. Further, the body1comprises a plurality of openings112respectively aligned with the scales212of the spring-attaching members21.

Referring toFIGS. 3 and 4, in a case that any one of the springs13becomes slack after a period of time and thus requires adjustment, a tool T (such as a hexagonal wrench) can be used to drive the adjusting screw22on the associated centrifugal weight11. As mentioned above, the associated spring-attaching member21moves along the longitudinal direction of the through-hole111of the associated centrifugal weight11when the adjusting screw22turns, thereby adjusting the tightness of the spring13. This is because an end of the spring-attaching member21is attached to the other end of the associated spring13. The scale212on the associated spring-attaching member21provides an indication of the extent of adjustment so that a worker may proceed with precise adjustment of the spring13to the required tightness. And the associated opening112of the body1allows the worker to view the scale212and thus to obtain precise adjustment. Preferably, each opening111of the body11extends along a longitudinal direction of the associated spring13to allow removal and replacement of the associated spring13via the opening111. Thus, in a case that a spring13is broken, the associated opening112of the body1allows the worker to proceed with the replacement of a new spring without the need of dismantling the whole clutch device. This effectively simplifies the replacement and shortens the time for replacement.

Referring toFIGS. 1 and 2, the body1may further comprise a fixing ring19that includes a plurality of fixing holes191aligned with the screw holes162of the axles161, with a screw192extending through each fixing hole191and the screw hole162of the associated axle161to thereby fix the fixing ring19to the axle161and the body1. The strength of the body1is thus improved, which is advantageous to withstand larger torque during operation of the clutch.

Preferably, each adjusting screw22comprises an enlarged head22athat abuts against a shoulder portion of the through-hole111of the associated centrifugal weight11. Thus, when the adjusting screw22is turned by the tool T, the adjusting screw22turns freely without any longitudinal displacement along the longitudinal direction of the through-hole111.

Although a specific embodiment has been illustrated and described, numerous modifications and variations are still possible without departing from the essence of the invention. The scope of the invention is limited by the accompanying claims.