192 clutches and power-stop control – Clutches – Axially engaging
Reexamination Certificate
2000-10-25
2002-11-19
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Axially engaging
C192S070270, C192S070300, C192S090000, C192S214000
Reexamination Certificate
active
06481552
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to a clutch apparatus connected to a crankshaft via an elastic member. More specifically, the present invention relates to a clutch apparatus including a clutch cover assembly axially disposed on the engine side of a clutch disk and a damper mechanism disposed between the crankshaft and the clutch cover assembly.
2. Background Information
A clutch apparatus is an apparatus that enables transmission of driving force from an engine to an input shaft of a transmission and disables the transmission of the driving force as required. The clutch apparatus basically includes a friction drive plate receiving the driving force from a crankshaft of the transmission, a clutch disk disposed adjacent to the friction drive plate, and a clutch cover assembly for urging the clutch disk against the friction drive plate and releasing the clutch disk from the friction drive plate as required. The clutch cover assembly includes a clutch cover arranged to rotate integrally with the friction drive plate, a pressure plate housed in the clutch cover adjacent to the clutch disk, and an urging member supported by the clutch cover for urging the pressure plate toward the clutch disk and the friction drive plate.
One known type of the clutch cover assembly is axially disposed on the engine side of the drive plate. In this instance, a release mechanism for releasing the clutch by applying a load to the clutch cover assembly is axially disposed on the transmission side of the friction drive plate. By way of example, the release mechanism comprises a cover member, a release member and a lever member. The cover member is secured to the axial transmission side of the friction drive plate. The release member extends through the friction drive plate and has one end forming an engaging section for engaging with the pressure plate. The lever member is levered against other end of the release member while being fulcrumed on a portion of the cover member. As the load is applied to the lever member from the drive mechanism, the lever member axially forces the release member toward the engine side while being fulcrumed on the cover member. As a result, the pressure plate overcomes the urging force of the urging member and disengages from the clutch disk. In this way, the clutch engagement is released in the clutch apparatus.
In the described prior art clutch apparatus, the clutch cover is supported, for example, at its inner peripheral end by the crankshaft or other member. Therefore, when bending vibrations are transmitted from the engine to the clutch apparatus, the entire clutch apparatus is subjected to the bending vibrations, resulting in vibrational resonances of the entire clutch apparatus.
Such clutch cover assembly may be secured to the crankshaft of the engine, for example, via a damper mechanism. A damper mechanism is disposed, for example, between the friction drive plate and a member disposed on the engine side for absorbing and reducing torque fluctuations transmitted from the engine. The damper mechanism generally includes an input side member secured to the member disposed on the engine side, an output side member secured to the clutch cover assembly, and an elastic member or springs for elastically connecting the input side member and the output side member with each other in a rotational direction. In such case, when torque fluctuations are transmitted from the engine, the springs in the damper mechanism are compressed in a rotational direction so as to absorb and reduce the torque fluctuations. Some noise and vibration problems in the drive train of the vehicle are, for example, gear-tooth noises and internal resonance noises that occur while the vehicle is running.
In order to reduce such noises and vibrations, it is necessary to minimize the torsional rigidity in the acceleration and deceleration torque ranges so as to set a torsional resonance frequency of the drive train below a practical engine speed range. In the damper mechanism, it is conceivable to increase the torsion angles of the elastic members or to arrange a plurality of elastic members operating serially in order to reduce the torsional rigidity of the damper mechanism.
On the other hand, if the elastic members have such reduced torsional rigidities, a resonance point must be passed in a low engine speed range (for example, equal to or below 500 rpm) at the engine start up and also at the engine stall. During this period, excessive torque fluctuations may occur, possibly causing damage of the damper mechanism and/or increase of the noises and vibrations. Such problems are avoided, for example, by use of one type of known lock mechanism that locks members disposed on the opposing sides of the damper mechanism while the engine speed is in the low engine speed range and unlocks these members while the engine speed is in a high engine speed range to allow operation of the damper mechanism. This lock mechanism generally includes a lock member and an elastic member. The lock member can be urged to a locking and engaging position by the elastic member to prevent relative rotation of the clutch cover assembly with respect to a member disposed on the crankshaft side and can unlock the clutch cover assembly by moving the clutch cover assembly to an unlock position with aid of centrifugal force as the engine speed reaches the high engine speed range. The use of such lock mechanism will disadvantageously results in the more complex structure and the increased number of components.
In the assembly operation of the described prior art clutch apparatus, the damper mechanism has been pre-mounted to one of the clutch apparatus and the member disposed on the engine side. In this state, when the engine is joined to the transmission, the damper mechanism must be secured to the other of the clutch apparatus and the member disposed on the engine side, for example, with bolts, rivets or the like.
Since the fastening members, such as the bolts, the rivets or the like, must be used in the assembly of the clutch apparatus, the work efficiency of the assembly operation is intrinsically low.
In view of the above, there exists a need for a clutch apparatus which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a clutch apparatus that is constructed to make the assembly of the clutch apparatus much easier.
Another object of the present invention is to provide a clutch apparatus that reduces the negative effects due to the bending vibrations transmitted from the engine in the clutch apparatus that has the clutch cover assembly axially disposed on the engine side of the clutch disk.
Another object of the present invention is to provide a clutch apparatus that suppresses the resonant vibrations in the low engine speed range by simplifying the structure in the clutch apparatus that connects the clutch cover assembly to the crankshaft via the damper mechanism.
In accordance with a first aspect of the present invention, there is provided a clutch apparatus for enabling and disabling transmission of driving force from a crankshaft of an engine to an input shaft of a transmission by engaging and disengaging a clutch disk, respectively. The clutch apparatus includes a clutch cover assembly for engaging and disengaging the clutch disk, and a damper mechanism for elastically connecting the clutch cover assembly to the crankshaft in a rotational direction. In this clutch apparatus, since the clutch cover is connected to the crankshaft via the damper mechanism, the structure is relatively simple in comparison to that of the prior art.
In accordance with a second aspect of the present invention, the clutch apparatus of the first aspect of the present invention has the damper mechanism including an elastic member that is retained by one of the cra
Bonck Rodney H.
Exedy Corporation
Shinjyu Global IP Counselors, LLP
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