Rotary shafts – gudgeons – housings – and flexible couplings for ro – Overload release coupling – Torque transmitted via frictional engagement of planar...
Reexamination Certificate
1999-12-10
2001-03-13
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Overload release coupling
Torque transmitted via frictional engagement of planar...
C464S046000, C464S030000, C192S056550
Reexamination Certificate
active
06200221
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a power transmission apparatus and, more particularly, to a power transmission apparatus having a torque limiter mechanism such as a compressor for an automobile air conditioner.
As a conventional power transmission apparatus of this type, for example, one described in Japanese Utility Model Publication No. 6-39105 is known. In the power transmission apparatus described in this reference, fitting holes are formed in axially opposing side surfaces of the pulley (driving rotary member) of a compressor (driven device) and a hub (driven rotary member) mounted on the rotating shaft of the compressor. A connecting member comprised of a member that can be broken upon application of an overload is press-fitted in these fitting holes to form a torque limiter mechanism. When an overload acts on the rotating shaft, a power from a vehicle engine (driving device) breaks the connecting member.
In the conventional power transmission apparatus described above, the connecting member is broken when an overload is temporarily applied to the rotating shaft due to some reason. The compressor cannot be driven again unless the connecting member is exchanged for a new one.
In order to solve the above problem, a power transmission apparatus disclosed in, e.g., EP 0864454 A2 is proposed. In this power transmission apparatus, a washer is interposed between an inner holding member and an arc-shaped projection formed on the flange of a hub. When the inner holding member is pressed by a coned disc spring through another washer, the inner holding member is connected to the two washers through frictional engagement. When an overload is applied, the hub washer is moved into a recess formed in the arc-shaped projection to displace the inner holding member toward the hub, so that frictional engagement is canceled. Therefore, power transmission can be disconnected in a nondestructive manner.
In the power transmission apparatus disclosed in EP 0864454 A2 described above, after power transmission is disconnected, the flange of the inner holding member, the arc-shaped projection of the hub, and the washers slide on each other. Due to this structure, a drag torque may be generated, or a sliding noise and friction heat may be easily generated. In particular, when friction heat is generated, it degrades a rubber member connecting the outer and inner holding members to each other. When frictional engagement is canceled and power transmission is disconnected, the inner holding member and the washers become movable in the axial direction. Then, when the inner holding member and the washers are moved by vibration or the like, noise is produced.
SUMMARY OF THE INVENTION
It is, therefore, a principal object of the present invention to provide a power transmission apparatus in which noise or friction heat is not generated due to its structure even when power transmission is disconnected because of an overload.
In order to achieve the above object, according to the present invention, there is provided a power transmission apparatus comprising a driving rotary member rotatably supported on an outer surface of a cylindrical housing of a driven device through a bearing, a driven rotary member attached to a rotating shaft coaxially arranged in the cylindrical housing of the driven device, and a torque limiter mechanism for connecting the driven rotary member and the driving rotary member to each other and limiting torque transmission from the driving rotary member to the driven rotary member when an overload is applied to the driven rotary member, the torque limiter mechanism having a plurality of holding portions fixed to either one of the driving rotary member and the driven rotary member and aligned substantially equidistantly in a circumferential direction, an opposing portion provided to either one of the driving rotary member and the driven rotary member and opposing the holding portions, and an elastic member frictionally connected to the holding portions and the opposing portion and fixed to the remaining one of the driving rotary member and the driven rotary member, the elastic member having connecting portions frictionally connected to the holding portions and the opposing portion and corresponding in number to the holding portions, and an elastic support fixed to the remaining one of the driving rotary member and the driven rotary member and imparted with an elastic restoration force for disengaging the connecting portions toward either one of upper and lower surfaces of the holding portions, wherein the connecting portions and the holding portions, and the connecting portions and the opposing portion are frictionally connected to each other, and the elastic support elastically deforms in an axial direction.
REFERENCES:
patent: 3503478 (1970-03-01), Neumann
patent: 4043149 (1977-08-01), Tuninetti
patent: 4542812 (1985-09-01), Westley
patent: 864454A2 (1998-09-01), None
patent: 6-39105 U (1994-10-01), None
patent: 10-252857 (1998-09-01), None
patent: 12-179569 (2000-06-01), None
Busujima Katsunao
Kurosu Yoshihiro
Maejima Enjiro
Blakely & Sokoloff, Taylor & Zafman
Browne Lynne H.
Dunwoody Aaron
Ogura Clutch Co. Ltd.
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