Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
1999-05-12
2001-01-30
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S057000
Reexamination Certificate
active
06179592
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a system which moves the flanks of a scroll compressor out of engagement when reverse rotation occurs.
Scroll compressors are becoming widely utilized in refrigerant compression applications. Scroll compressors typically include two scroll members each including a base and a generally spiral wrap extending from the base. The two wraps interfit to define a plurality of compression chambers. A refrigerant is trapped in the chambers, and one of the two scroll members orbits relative to the other to reduce the size of the compression chambers. When this occurs, the refrigerant is compressed.
One early challenge in the design of scroll compressors was to achieve a good seal between the flanks of the scroll wrap when they define the compression chambers. Various mechanisms were developed for moving the flanks into engagement to define the compression chambers. Among the components of the standard scroll compressors which allow the orbiting movement, and further allow the flanks to move into engagement is an eccentric pin mounted on the driving shaft which is received in a slider block in a boss extending from the base of the orbiting scroll member.
One problem associated with scroll compressors is reverse rotation. With reverse rotation, the orbiting scroll member is driven in a reverse direction. This can occur if the motor is improperly connected, or upon shut down of the scroll compressor. In some cases, at shut down, an entrapped compressed refrigerant drives the orbiting scroll member in an opposed direction. Reverse rotation is undesirable.
Various mechanisms have been developed to move the scroll members out of engagement when reverse rotation occurs. Generally, these mechanisms have been complex, and not always reliable. Thus, it would be desirable to develop a relatively simply and reliable mechanism for moving the flanks of the scroll wraps out of engagement upon the occurrence of reverse rotation.
SUMMARY OF THE INVENTION
In a disclosed embodiment of this invention, structure is provided between the eccentric pin and the slider block in an orbiting scroll that causes the slider block to rotate relative to the eccentric pin when reverse rotation occurs. Essentially, the forces on the slider block can be defined, and the slider block and eccentric pin designed such that when the scroll compressor is orbiting in the proper forward direction, two flat surfaces of the pin and slider block are in engagement for transmitting driving force. This also holds the flanks of the wraps in engagement.
However, when reverse rotation occurs, a separating force which had been less than a holding force during forward rotation becomes predominant and exceeds the holding force. The separating force thus causes the slider block to move to a position such that the flat surfaces are out of engagement. After a small amount of initial movement a pivot point between the slider block and eccentric pin moves into engagement. After that initial movement, the slider block pivots relative to the eccentric pin, and the flanks of the scroll wrap are held out of contact with each other. Thus, should reverse rotation begin, the flanks are moved out of engagement. If this reverse rotation is due to faulty wiring, there would be no detrimental side effects of the reverse rotation since little compression will occur.
In one embodiment, the pivot point is defined by a plug protruding from an inner bore in the slider block into a recess in the eccentric pin. In a second embodiment, the pivot point is defined by a plug surface which moves into contact with an outer surface of the eccentric pin, but not into any groove. In a third embodiment, a separate pin on the shaft moves into a groove in the slider block.
These and other features of the present invention can be best understood from the following specification and drawings, the following which is a brief description.
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patent: WO 9946506 (1999-09-01), None
Barito Thomas R.
Hugenroth Jason J.
Carlson & Gaskey & Olds
Scroll Technologies
Vrablik John J.
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