Rotary shafts – gudgeons – housings – and flexible couplings for ro – Having lubricating means
Reexamination Certificate
1997-02-21
2001-01-09
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Having lubricating means
C464S084000, C464S101000
Reexamination Certificate
active
06171192
ABSTRACT:
BACKGROUND OF THE INVENTION
A. Field of the Invention
The present invention relates to a damper mechanism and a flywheel assembly.
B. Description of the Background Art
In automotive vehicles, a damper mechanism is often included in a flywheel/clutch mechanism attached to the crankshaft of the automobile's engine, between the engine and a transmission for absorbing a torque variation produced by the engine. The damper mechanism may be disposed in either a clutch disk assembly or a flywheel of the flywheel clutch mechanism. The damper mechanism includes input and output members which can rotate relatively to each other, and also includes elastic members such as coil springs for restricting relative rotation of these members, and a friction generating mechanism which generates a friction to damp vibration when these members rotate relatively to each other.
For example, parts of a damper mechanism arranged between first and second flywheels of a flywheel assembly are disposed in a chamber filled with viscous fluid. Owing to lubrication by the viscous fluid, it reduces a friction between an elastic member and a support member and between other sliding portions at the friction generating mechanism or the like.
In the conventional damper mechanism described above, a film of the viscous fluid must be present between sliding portions of the elastic member and the support member, otherwise, wearing or abrasion occurs between the engaging sliding surfaces. When such a device sits unused for an extended period of time, gravity might cause such a film of viscous fluid to drain from some surfaces. Further, the viscous fluid may leak from the chamber, in which case a lubricity is further impaired.
In the damper mechanism, coil springs forming the damper mechanism require a circumferentially and axially large space due to their constructions. Therefore, it is difficult to arrange the damper mechanism of the above structure in a front wheel drive vehicle, in which an axial space is particularly restricted.
Japanese Laid-Open Patent Publication No. 6-174011 has disclosed a damper mechanism, in which an undulated or curved plate springs are used instead of coil springs for reducing a required space. Each undulated plate spring is formed of a plate member which has a constant width and a corrugated form. The undulated plate spring is formed of ring portions having open ends, and lever portions which connect the open ends of the ring portions for enabling a series operation of the ring portions. The paired lever portion extend in a diverging form from the common ring portion, and have a higher rigidity than the ring portion.
The undulated plate spring is arranged in an arc-shaped chamber defined by input and output members for transmitting a torque from the input member to the output member. When a torsional vibration is transmitted to the input member, the undulated plate spring is compressed in the rotation direction. Thereby, an open angle between the paired lever portions decreases, so that a bending moment is exerted on the ring portion. As a result, the ring portion and the lever portion elastically bend in the same direction around a fulcrum formed of a center (apex) of the ring. When the torsion angle increases, ends of each ring portion are brought into contact, and thereafter, the ring portion elastically bends around the fulcrum formed of the ends. An elastic energy is distributed and stored in the plurality of ring portions.
The lever portion has a higher rigidity than the ring portion, and has a uniform thickness. Therefore, the lever portion cannot store a sufficiently large elastic energy. As a torque transmitted to the damper mechanism increases, a relative torsion angle between the input and output members increases, so that the undulated plate spring is compressed to a larger extent. When a load larger than an ordinary torque is exerted on the undulated plate spring, an excessively large stress breaking the undulated plate spring may be produced at the bent plate spring.
SUMMARY OF THE INVENTION
An object of the invention is to improve a lubricity in a damper mechanism.
Another object of the invention is to increase the elastic energy storage capacity of the undulated plate spring.
A still another object of the invention is to reduce a stress of a undulated plate spring for preventing breakage.
In accordance with one aspect of the present invention, a damper mechanism includes an input member and an output member configured for limited relative rotary displacement with respect to the input member. A chamber housing is disposed between the input and output members and a first portion of the chamber housing is connected to the input member for rotation therewith. A damper mechanism is disposed in the chamber housing elastically connecting the input and output members for limited relative rotary displacement therebetween and damping torsional vibration therebetween. The damper mechanism includes an elastic member that elastically connects the input and output members. The elastic member further contacts at least one surface of the chamber housing thereby defining a hysteresis vibration dampening mechanism whereby, in response to relative rotary displacement between the input and output members, contact between the elastic member and the surface of the chamber housing generates friction. A powder solid lubricant is disposed in the chamber housing providing lubrication between the elastic member and the surface of the chamber housing to augment the operation of the hysteresis vibration dampening mechanism and also to reduce wear on other portions of the elastic member that may contact the chamber.
When a torsional vibration is supplied to the viscous damper mechanism, the input and output members cyclically rotate relatively to each other. In this operation, the powder solid lubricant lubricates sliding portions of the damper unit, so that a friction is suppressed. In particular, since the powder solid lubricant has good absorption or absorptive properties with respect to respective members and can keep a good adhesion force after absorption, a high lubricating effect can be achieved.
Further, when a relative rotation angle between the input and output members increases, the ring portions in the first row are brought into contact with each other and the ring portions in the second row are brought into contact with each other, so that relative rotation between the input and output members stops. Thus, the ring portions in both the rows function as a stop mechanism. As a result, the undulated plate spring is suppressed from receiving a load larger than a set or intended load, so that generation of a large stress is suppressed. In particular, the damper mechanism has a simplified structure because the undulated plate spring functions as the stop mechanism of the damper mechanism.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description, when taken in conjunction with the accompanying drawings.
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Hildebrand, Feinmechanische Bauelement (Fine Mechanical Construction Elements) 1968 pp. 464-468.
Rompp Chemie Lexikon (ROMPP Chemical Dictionary) 1995, pp. 2838 & 5064.
Fukushima Hirotaka
Yamashita Kazuhiro
Binda Greg
Browne Lynne H.
Exedy Corporation
Shinjyu Global IP Counselors, LLP
LandOfFree
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