Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2000-03-24
2001-08-07
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
Reexamination Certificate
active
06270328
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a scroll compressor wherein the crankcase and the non-orbiting scroll are interconnected in a way that reduces assembly difficulties, and further reduces the possibility of weld spatter.
Scroll compressors are becoming increasingly popular for refrigerant compression applications. In a standard scroll compressor, a first scroll member is formed with a base and a generally spiral wrap extending from the base. A second scroll member has a base and a generally spiral wrap interfitting with the wrap of the first scroll member. The second scroll member is caused to orbit relative to the first scroll member and compression chambers defined between the two scroll members are reduced in volume to compress an entrapped refrigerant.
A crankcase supports the second scroll member, and sits on an opposed side of the second scroll member from the first scroll member. In some applications, the first scroll member is fixed relative to the crankcase. In other scroll compressors the first scroll member is allowed to move axially, but is prevented from orbiting or rotating. The crankcase is typically positioned relative to the first scroll member by dowel pins, or other structure extending between the two members. Alternatively, automated assembly and measurement equipment have been utilized to properly position the two components. These approaches have been somewhat complex and undesirable.
The standard crankcase includes a plurality of circumferentially spaced crankcase towers. These are structures extending axially beyond the second scroll member, which typically extend to be in close relationship with the first scroll member.
Scroll compressors are received in a sealed housing chamber. The housing chamber are formed of a central cylindrical shell which is welded to an end cap by a girth weld. The circumferentially spaced towers on the crankcase block the ingress of weld material, known as weld spatter, from moving between the end cap and the center shell into the housing chamber. However, the ingress of welding material does occur in the gaps between the crankcase towers.
The crankcase towers have a structural and casting function, and thus it would not be desirable to simply eliminate the crankcase towers, or to form them around the entire circumference of the crankcase.
The present invention is directed to eliminating the above-discussed challenges for scroll compressors.
SUMMARY OF THE INVENTION
In the disclosed embodiment of this invention, tabs are formed on the first scroll member at circumferentially spaced locations. The tabs are aligned with the spaces between the crankcase towers and move into those spaces when the scroll compressor is assembled. The tabs extend downwardly for a sufficient distance to block the ingress of weld material between the center shell and the end cap at the circumferential locations between the crankcase towers. Thus, the tabs eliminate the weld spatter problem.
In another feature of this invention, the tabs on the first scroll are spaced by grooves. The grooves are aligned with the crankcase towers. At least one of the grooves is formed such that the circumferential edge to edge distance of the groove provides a very close tolerance, or even a light interference fit with one of the corresponding crankcase towers. In this way, the groove to crankcase tower interconnection provides tight rotational positioning tolerance between the crankcase and the non-orbiting scroll.
In further features of this invention, the groove has its inner periphery cut at a close radius to match the inner periphery of the crankcase tower. In this way, positioning the crankcase towers in the circumferentially spaced grooves serves to position the non-orbiting scroll and the crankcase at a desired relative location in a plane perpendicular to the axis of movement of the orbiting scroll.
Thus, the use of tabs extending between the crankcase towers, with corresponding grooves aligned with the crankcase towers provides valuable benefits. These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
REFERENCES:
patent: 5445507 (1995-08-01), Nakamura et al.
patent: 5551851 (1996-09-01), Williams et al.
patent: 6027321 (2000-02-01), Shim et al.
Herbert Jay Andrew
Milliff Tracy
Murphy Paul
Williams John R.
Carlson & Gaskey & Olds
Scroll Technologies
Vrablik John J.
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