Claims
- 1. In a variable displacement wobble plate compressor having a guide rod that operates through a multiple axis joint to prevent rotation while permitting angulation of a wobble plate, the improvement comprising a cylindrical bearing body slidably received on opposite sides in a pair of oppositely facing, concave, cylindrical, radially extending guides on the wobble plate, said bearing body having a slot therethrough converging inwardly from an oval shape on opposite sides of the bearing body so as to slidably receive the guide rod thereabout and permit angulation of the bearing body relative to the guide rod while maintaining contact about the guide rod with the bearing body in the slot, said guide rod and slot having parallel flat sides that contact over a substantial surface area to prevent rotation of the wobble plate.
- 2. In a variable displacement wobble plate compressor having a guide rod that operates through a multiple axis joint to prevent rotation while permitting angulation of a wobble plate, the improvement comprising a bearing body slidably received on radially extending guides on the wobble plate, said bearing body having a slot therethrough converging inwardly from an oval shape on opposite sides of the bearing body so as to slidably receive the guide rod thereabout and permit angulation of the bearing body relative to the guide rod while maintaining contact about the guide rod with the bearing body in the slot, said guide rod and slot having parallel flat sides that contact over a substantial surface area to prevent rotation of the wobble plate.
TECHNICAL FIELD
This is a continuation-in-part of U.S. patent application Ser. No. 888,713, filed July 24, 1986 and now abandoned.
This invention relates to variable displacement wobble plate compressors and more particularly to the multiple axis joint that operates between the guide rod and wobble plate therein to prevent rotation while permitting angulation of the wobble plate.
In a variable displacement wobble plate compressor such as that used in motor vehicle engine air conditioning systems, a round guide rod operates through a multiple axis joint to prevent rotation while permitting angulation of the wobble plate. The most advanced of these joints in terms of low wear and reliability comprises a ball that is journaled on the guide rod and received on opposite sides in spherical pockets in two oppositely arranged shoes that each have a semi-cylindrical profile that rides in a radial, concave, semi-cylindrical guide formed in the wobble plate. However, the manufacturing costs of the ball and two shoes is significant even though the ball may be produced on a screw machine. The significant cost results mainly from the shoes which are generally formed with powdered metal and because of their complexity and thin cross section suffer a significantly high rejection rate in the manufacturing process. Furthermore, the assembly costs of these parts is significant because proper orientation of all three must be maintained. Moreover, noise can be encountered when a loose fit occurs in these parts due to tolerance stack up results.
The present invention reduces the three-piece shoe-ball-shoe assembly to a single piece without any significant loss in wear efficiency and reliability. This new single piece is formed as a bearing body having an outside cylindrical profile that mates with the radial, concave, cylindrical guides on the wobble plate allowing the required relative radial motion between the bearing body and the plate. And instead of an intermediate bearing, there is formed a tapered slot through the cylindrical bearing body that directly receives the guide rod and allows both linear and angular motion of the bearing body on the rod. In one embodiment, the guide rod is round as is conventional and the bearing body slot is shaped accordingly at the place of engagement therewith. In another embodiment, the guide rod is formed with two parallel flat sides and the bearing body slot is shaped accordingly with flat sides that engage therewith. As a result, there is surface contact directly between the wobble plate and the bearing body and either line contact between the latter and the round guide rod or substantial area between the bearing body and guide rod where the slot and guide rod are flat sided. Manufacturing advantages result in that the single bearing body can be machined from rod stock on a screw machine or molded of powdered metal or plastic. Further as to the latter, a plastic is preferably selected that has both lubricity and a high damping factor not normally available in metal. In addition, the assembly costs are reduced with the elimination of two parts and their required orientation.
US Referenced Citations (13)
Continuation in Parts (1)
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Number |
Date |
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888713 |
Jul 1986 |
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Patent Grant
4745814
