192 clutches and power-stop control – Clutches – Automatic
Reexamination Certificate
2000-02-07
2001-11-06
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Automatic
Reexamination Certificate
active
06311814
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a one-way clutch of a type employing rollers. This one-way clutch is built into a pulley mounted to auxiliary machinery driven by a crankshaft of an engine of an automobile or the like through a belt, for example.
A conventional one-way clutch of this type is described. An inner annular body and an outer annular body are disposed inside and outside each other in a diameter direction and concentrically with each other. Wedge-shaped spaces each with a gap in a diameter direction narrowing in one direction in a circumferential direction are formed at some positions on a circumference in a gap through which both the annular bodies face each other. A roller is individually disposed in each wedge-shaped space. Between both the annular bodies, a cage having pockets extending to open inside and outside in a diameter direction at positions in phase with the wedge-shaped spaces is provided. Each roller is individually housed by each corresponding pocket. An elastic member is housed by each pocket. Each roller is elastically biased by each elastic member toward a narrower side (lock side) in one direction in the circumferential direction in the wedge-shaped space.
The wedge-shaped spaces are formed by providing cam faces to one of the annular bodies (an outer peripheral face of the inner annular body or an inner peripheral face of the outer annular body) and a wedge angle of the wedge-shaped space is generally set at 9° to 11°.
The wedge angle is an angle (&agr;, &bgr; which will be described later) at which two tangents intersect each other, one of the tangents being a tangent at a point of contact at which the roller contacts the outer peripheral face of the inner annular body and the other of the tangents being a tangent at a point of contact at which the roller contacts the inner peripheral face of the outer annular body when the roller rolls to the lock side.
In the above structure of the one-way clutch, when each roller rolls to the narrower side in one direction in the circumferential direction of the wedge-shaped space, the clutch is brought into a lock state in which the inner annular body and the outer annular body are integrated with each other through the rollers and rotate synchronously. When each roller rolls to a wider side in the other direction in the circumferential direction of the wedge-shaped space, the clutch is brought into a free state in which the inner annular body and the outer annular body rotate with respect to each other. In this manner, depending on a position in the wedge-shaped space to which each roller rolls, the clutch is switched between the lock state and the free state. In conventional clutches having the above wedge angle, a lock malfunction may occur and a response property of a clutch operation is degraded when the roller rolls to the narrower side of the wedge-shaped space to bring the clutch into the lock state.
SUMMARY OF THE INVENTION
Therefore, it is a main object of the present invention to provide a one-way clutch in which generation of a lock malfunction is prevented and a response property of a clutch operation is improved.
It is another object of the invention to provide a one-way clutch in which a wedge angle of each wedge-shaped space is set at a proper value, switching between a lock state and a free state is made smooth, and the response property of the clutch operation is improved.
Other objects, features, and advantages of the invention will become apparent from the following descriptions.
According to the invention, there is provided a one-way clutch including an inner annular body, an outer annular body which is disposed outside the inner annular body and concentrically with the inner annular body and constitutes wedge-shaped spaces at some positions in a circumferential direction between the inner annular body and the outer annular body, each wedge-shaped space being narrowing in one direction in the circumferential direction, and a plurality of rollers each disposed in each wedge-shaped space for switching between a lock state in which each roller rolls to a narrower side of the wedge-shaped space to integrate both the annular bodies with each other to allow both the annular bodies to rotate synchronously and a free state in which each roller rolls to a wider side of the wedge-shaped space to cancel the lock state to allow both the annular bodies to rotate with respect to each other, wherein the inner annular body and the outer annular body have a structure in which a wedge angle of each wedge-shaped space is set at 4° to 8°.
If the wedge angle of the wedge-shaped space is set at the above value, an engagement position of each roller is at a position in the wedge-shaped space with the narrowest wedge angle and is relatively shallow when the roller is positioned on the narrower side of the wedge-shaped space and gaps between each roller and both the annular bodies are relatively small when the roller is positioned on the wider side of the wedge-shaped space. Therefore, the rollers move smoothly in switching between the lock state and the free state.
REFERENCES:
patent: 4909366 (1990-03-01), Tanaka
patent: 4987984 (1991-01-01), McCreary
patent: 5482144 (1996-01-01), Vranish
patent: 5676225 (1997-10-01), Miyata
patent: 5927456 (1999-07-01), Monahan et al.
patent: 6116393 (2000-09-01), Ooitsu et al.
patent: 2582761 (1986-12-01), None
patent: 10-238561 (1998-09-01), None
Abstract of Japanese Appln. No.: 03249435, 11/91, Yoshiaki.
Fujiwara Hideki
Nakagawa Yoshitaka
Tazumi Hajime
Terada Tadahiro
Bonck Rodney H.
Jordan and Hamburg LLP
Koyo Seiko Co. Ltd.
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