Scroll compressor with rolling element bearings
A scroll compressor includes a housing and a rotatable drive shaft disposed within the housing and having an eccentric end portion. First and second support bearings rotatably couple the drive shaft with the housing and each includes a plurality of rolling elements, at least one of which is ceramic, and an annular cage formed of a polymeric material. A scroll member is disposed within the housing chamber and a drive bearing rotatably couples the shaft eccentric portion with the scroll member such that the scroll member orbits about the central axis. The drive bearing includes a plurality of rolling elements, at least one of which is ceramic, and an annular cage formed of a polymeric material. Further, a solution formed of refrigerant and oil is directed to each one of the drive bearing and the first and second support bearings so as to lubricate the rolling elements.
1 . A scroll compressor comprising:
a housing having an interior chamber;
a drive shaft disposed within the housing chamber, rotatable about a central axis, and having an eccentric end portion with a centerline spaced from and extending parallel to the central axis;
a movable scroll member disposed within the housing chamber;
a rolling element drive bearing configured to rotatably couple the drive shaft with the movable scroll member such that the scroll member orbits about the central axis, the drive bearing including at least one row of needle rolling elements disposed between the shaft eccentric end portion and the scroll member, at least one of the needle rolling elements being formed of a ceramic material and at least one of the needle rolling elements being formed of steel; and
a quantity of a solution formed of refrigerant and oil disposed within the housing, the solution being directed into the drive bearing to lubricate the at least one row of rolling elements.
2 . The compressor as recited in claim 1 , wherein the at least one row of rolling elements includes a plurality of needle rolling elements formed of a ceramic material.
3 . The compressor as recited in claim 1 , wherein the movable scroll member includes first and second axial ends, the first axial end being engageable with a mating fixed scroll, and a cylindrical bore extending axially inwardly from the second axial end, the drive bearing being disposed within the cylindrical bore.
4 . The compressor as recited in claim 3 , wherein the cylindrical bore of the movable scroll member has an inside diameter with a value of between nineteen millimeters and eighty millimeters and the eccentric portion of the shaft has an outside diameter with a value of between twelve millimeters and sixty millimeters.
5 . The compressor as recited in claim 3 , wherein the drive bearing includes an outer ring disposed within the bore of the cylindrical hub and the at least one row of rolling elements roll directly against an outer circumferential surface of the eccentric portion of the shaft.
6 . The compressor as recited in claim 5 , wherein the outer circumferential surface of the eccentric portion of the shaft has a surface roughness with an Ra value of no greater than one tenth of a micrometer (0.1 μm).
7 . The compressor as recited in claim 1 , wherein the drive bearing further includes an annular cage formed of a polymeric material, the cage having a plurality of circumferentially spaced pockets and each one of the row of rolling elements is disposed within a separate one of the pockets.
8 . The compressor as recited in claim 7 , wherein the polymeric material is polyetheretherketone or polyamide.
9 . The compressor as recited in claim 8 , wherein the drive bearing includes an outer ring connected with the scroll member and having an inner circumferential guide surface, the cage having an outer circumferential surface slidable against the guide surface of the outer ring.
10 . The compressor as recited in claim 1 , further comprising a first support bearing and a second support bearing spaced apart from the first support bearing along the central axis, the first and second support bearings rotatably coupling the drive shaft with the housing and each one of the first and second support bearings including at least one row of rolling elements, at least one of the rolling elements of each one of the support bearings being formed of a ceramic material.
11 . The compressor as recited in claim 10 , wherein each one of the first and second support bearings is a deep groove ball bearing.
12 . The compressor as recited in claim 10 , wherein a portion of the solution of refrigerant and oil is directed into each one of the first and second support bearings to lubricate the at least one row of rolling elements.
13 . The compressor as recited in claim 1 , wherein the shaft rotates at an intended angular speed during compressor operation and the drive bearing has a mean diameter sized such that the ndm factor of the bearing during compressor operation is no greater than three hundred thousand.
14 . A scroll compressor comprising:
a housing having an interior chamber;
a drive shaft disposed within the housing chamber, rotatable about a central axis, and having an eccentric end portion with a centerline spaced from and extending parallel to the central axis;
a first support bearing and a second support bearing spaced apart from the first support bearing along the central axis, the first and second support bearings rotatably coupling the drive shaft with the housing and each one of the first and second support bearings including at least one row of rolling elements and an annular cage formed of a polymeric material and having a plurality of pockets, each pocket retaining a separate one of the rolling elements;
a scroll member disposed within the housing chamber;
a drive bearing rotatably coupling the drive shaft with the scroll member such that the scroll member orbits about the central axis, the drive bearing including at least one row of needle rolling elements, at least one of the needle rolling elements being formed of a ceramic material and at least one of the needle rolling elements being formed of steel, and an annular cage formed of a polymeric material and having a plurality of pockets, each pocket retaining a separate one of the needle rolling elements; and
a quantity of a solution formed of refrigerant and oil disposed within the housing, the solution being directed to each one of the drive bearing and the first and second support bearings so as to lubricate the rolling elements.
15 . The compressor as recited in claim 14 , wherein the polymeric material of each annular cage is polyetheretherketone or polyamide.
16 . The compressor as recited in claim 14 , wherein the drive bearing includes an outer ring connected with the scroll member and having an inner circumferential guide surface, the annular cage of the drive bearing having an outer circumferential surface slidable against the guide surface of the outer ring.
17 . The compressor as recited in claim 14 , wherein the scroll member includes first and second axial ends, the first axial end being engageable with a mating fixed scroll, and a cylindrical bore extending axially inwardly from the second axial end, the drive bearing being disposed within the cylindrical bore.
18 . The compressor as recited in claim 17 , wherein the cylindrical bore of the movable scroll member has an inside diameter with a value of between sixty millimeters and eighty millimeters and the and the eccentric portion of the shaft has an outside diameter with a value of between twelve millimeters and twenty-four millimeters.
19 . The compressor as recited in claim 14 , wherein the drive bearing includes an outer ring disposed within the bore of the cylindrical hub and the at least one row of rolling elements roll directly against an outer circumferential surface of the eccentric portion of the shaft.
20 . The compressor as recited in claim 19 , wherein the outer circumferential surface of the eccentric portion of the shaft has a surface roughness with an Ra value of no greater than one tenth of a micrometer (0.1 μm).
21 . The compressor as recited in claim 14 , wherein each rolling element of the first and second support bearings is a ball.
22 . The compressor as recited in claim 14 , wherein the shaft rotates at an intended angular speed during compressor operation and the drive bearing has a mean diameter sized such that the ndm factor of the drive bearing during compressor operation is no greater than three hundred thousand.