Oiless rotary scroll air compressor crankshaft assembly

Details Oiless rotary scroll air compressor crankshaft assembly Oiless rotary scroll air compressor crankshaft assembly

2000-06-01

2001-12-11

Denion, Thomas (Department: 3748)

Rotary expansible chamber devices

Working member has planetary or planetating movement

Helical working member, e.g., scroll

C418S055100, C418S094000

Reexamination Certificate

active

06328545

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates, in general, to scroll compressors which are used to compress a fluid, for example, a gas such as a refrigerant for cooling purposes or ambient air in order to furnish a compressed air supply.
More particularly, the present invention relates to a novel and inventive crankshaft assembly for an oiless rotary scroll compressor.
BACKGROUND OF THE INVENTION
So-called “scroll” compressors have achieved wider application recently, particularly in the fields of refrigeration and air conditioning, due to a number of advantages which they possess over reciprocating type compressors. Among these advantages are: low operating sound levels; reduction in “wear parts” such as compression valves, pistons, piston rings and cylinders (resulting in reduced maintenance); and increased efficiency as versus reciprocating compressor designs.
DESCRIPTION OF THE RELATED ART
While the number of wear parts in a scroll compressor may be reduced in comparison to a reciprocating type compressor, there are still a number surfaces which move relative to one another and lubrication between these surfaces cannot be ignored. One design for a refrigerant scroll compressor utilizes an oil sump located in the lowermost portion of the compressor housing and an oil pump which draws oil from the sump upward to lubricate the moving parts of the compressor. The oil used as a lubricant in such a design is relatively free to mix with the air which is being compressed. Lubricating oil which becomes suspended in the refrigerant is, for the most part, separated therefrom by changing the direction of flow of the refrigerant and by impinging the refrigerant on surfaces located within the compressor. After it is separated, the oil is then drained back to the oil sump.
However, due to the gas having been relatively free to mix with the oil lubricant, the compressed gas exiting the scroll compressor may still have a relatively high degree of oil content.
Such oil content may carry over to the compressed gas supply system and have deleterious effects such as reduced life of air driven mechanisms (e.g., air driven tools, brakes, etc.) which utilize the compressed gas supply as a power source.
OBJECTS OF THE INVENTION
One object of the present invention is the provision of a rotary scroll compressor which is “oiless” in the sense that the lubricant used to lubricate the various moving parts of the compressor is not intermingled with the gas being compressed. Thus, there is no contamination to the compressed gas due to the lubricant, and additional special provisions or designs need not be utilized for separating the lubricant from the compressed gas prior to using the compressed gas.
Another object of the present invention is the provision of a novel and inventive crankshaft assembly for such an oiless rotary scroll compressor which allows the rotational connection between the crankshaft and the orbiting rotational bearing to be periodically lubricated with ease, without any disassembly being required. In this regard, the novel and inventive crankshaft drives the orbiting scroll element via an orbiting rotational bearing which is affixed to a first distal end of the crankshaft and rotationally engages a hub portion projecting from the orbiting scroll element. This orbiting rotational bearing rotational bearing may be periodically lubricated (e.g., with lubricating grease) via a lubricating channel extending through the crankshaft which is readily accessible from a vantage point located outside of the housing of the scroll compressor.
In addition to the objects and advantages of the present invention described above, various other objects and advantages of the invention will become more readily apparent to those persons skilled in the relevant art from the following more detailed description of the invention, particularly when such description is taken in conjunction with the attached drawing Figures and with the appended claims.
SUMMARY OF THE INVENTION
In one aspect, the invention generally features a crankshaft assembly for a scroll compressor, the scroll compressor including a housing, a stationary scroll element mounted within the housing substantially stationary with respect to the housing, the stationary scroll element including a stationary spiral flange, an orbiting scroll element disposed within the housing, the orbiting scroll element including an orbiting spiral flange, the stationary and orbiting spiral flanges being intermeshed and nested with one another to define a spiraling compression pocket therebetween, each of the stationary and orbiting scroll elements having a central axis, and an orbital drive mechanism for driving the central axis of the orbiting scroll element in an orbit about the central axis of the stationary scroll element while maintaining the orbiting scroll element substantially non-rotational with respect to the stationary scroll element, the crankshaft assembly being for the driving of the orbiting scroll element in the orbit about the stationary scroll element and including a crankshaft member, the crankshaft member having a elongated shaft portion for rotation about a central axis of rotation thereof, and an orbiting rotational bearing affixed to the crankshaft member, the orbiting rotational bearing having a center of rotation which is radially offset with respect to the central axis of rotation of the crankshaft member, the orbiting rotational bearing being adapted to accept and rotationally engage a hub portion projecting from the orbiting scroll element.
In another aspect, the invention generally features an improvement in a scroll compressor of the type described, the improvement including an improved crankshaft assembly having a crankshaft member with a elongated shaft portion for rotation about a central axis of rotation, and an orbiting rotational bearing affixed to the crankshaft member, the orbiting rotational bearing having a center of rotation which is radially offset with respect to the central axis of rotation of the crankshaft member, the orbiting rotational bearing being adapted to accept and rotationally engage a hub portion projecting from the orbiting scroll element of the scroll compressor.
In yet another aspect, the invention generally features A scroll compressor including a crankshaft assembly for driving an orbiting scroll element in an orbit, including a housing, a stationary scroll element mounted within the housing substantially stationary with respect to the housing, the stationary scroll element including a stationary spiral flange, an orbiting scroll element disposed within the housing, the orbiting scroll element including an orbiting spiral flange, the stationary and orbiting spiral flanges being intermeshed and nested with one another to define a spiraling compression pocket therebetween, each of the stationary and orbiting scroll elements having a central axis, an orbital drive mechanism for driving the central axis of the orbiting scroll element in an orbit about the central axis of the stationary scroll element, the orbital drive mechanism including the crankshaft assembly, the crankshaft assembly including a crankshaft member, the crankshaft member having a elongated shaft portion for rotation about a central axis of rotation thereof; and, an orbiting rotational bearing affixed to the crankshaft member, the orbiting rotational bearing having a center of rotation which is radially offset with respect to the central axis of rotation of the crankshaft member, the orbiting rotational bearing being adapted to accept and rotationally engage a hub portion projecting from the orbiting scroll element.
The present invention will now be described by way of a particularly preferred embodiment, reference being made to the various Figures of the accompanying drawings, wherein:


REFERENCES:
patent: 4403927 (1983-09-01), Butterworth et al.
patent: 4585402 (1986-04-01), Morishita et al.
patent: 4702683 (1987-10-01), Inaba et al.
patent: 4886435 (1989-12-01), Sawai et al.
patent: 5026262 (1991-06-01), Baumann et al.
patent:

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