Two hybrid ball bearings and a compressor bearing arrangement

Abstract

Two hybrid ball bearings and a compressor bearing arrangement with two hybrid ball bearings for a rotatable support of a rotor of the compressor versus a stator of the compressor. The two hybrid ball bearings are arranged face-to-face or back-to-back, are configured with an optimal axial clearance depending on the inner diameter of a ring-shaped inner raceway element one of the hybrid ball bearings respectively a pitch diameter of one of the two hybrid ball bearings for a long bearing life in connection with an optimal compressor operating performance.

What is claimed is: 
     
         1 . Two hybrid ball bearings comprise:
 at least one ring-shaped inner raceway element having an inner diameter on which balls of at least one of the two hybrid ball bearings roll thereon, wherein   the two hybrid ball bearings are configured to provide an axial clearance with zero measuring and zero mounting loads as follows, if the two hybrid ball bearings are arranged face-to-face or back-to-back, wherein   if the inner diameter is smaller or equal to 80 mm, the axial clearance is between −5 and 5 or 25 and 40 μm, wherein   if the inner diameters is greater than 80 mm and smaller than or equal to 180 mm, the axial clearance is between −5 and 20 μm, and wherein if the inner diameters is greater than 180 mm, the axial clearance is between −5 and 30 μm.   
     
     
         2 . The two hybrid ball bearings according to  claim 1 , wherein the two hybrid ball bearings are in a not used, as new respectively, not run in condition and are identical. 
     
     
         3 . The two hybrid ball bearings according to  claim 1 , wherein raceway elements of the two hybrid ball bearings are made of steel, particularly a stainless high nitrogen steel for rolling bearings, the balls are made of a ceramic material and cages for the balls are made of plastic, in particular of glass-fiber-reinforced plastic, in particular comprising PEEK. 
     
     
         4 . The two hybrid ball bearings according to  claim 1 , wherein the first of the two hybrid ball bearings comprises: a first outer and a first inner ring-shaped raceway element, wherein the second of the two hybrid ball bearings comprises a second outer and a second inner ring-shaped raceway element, and wherein at least one hollow-cylindrical distance element, particularly a lubrication spacer or distance ring, is provided and positioned between the two outer and/or the two inner raceway elements. 
     
     
         5 . The two hybrid ball bearings according to  claim 1 , wherein the two hybrid ball bearings are hybrid angular contact ball bearings with contact angles between 10 and 40°, particularly between 15 and 30°. 
     
     
         6 . The two hybrid ball bearings according to  claim 5 , wherein the contact angles of the two hybrid ball bearings are different, and where particularly the contact angle of a first of the two hybrid ball bearings is between 10 to 20° and the contact angle of the second of the two hybrid ball bearings is between 21 to 35°. 
     
     
         7 . The two hybrid ball bearings according to  claim 1 , wherein at least one of the two hybrid ball bearings is configured for high rotation speeds between 2500 and 25000 rpm or nd m -values being between 500000 and 1200000 mm/60 s, wherein the nd m -value is the multiplication result of the rotation speed and the pitch diameter. 
     
     
         8 . The two hybrid ball bearings according to  claim 1 , wherein the two hybrid ball bearings are paired forming a synchronized set. 
     
     
         9 . Two hybrid ball bearings that are configured to provide the following axial clearance with zero measuring and zero mounting loads, when the two hybrid ball bearings are arranged face-to-face or back-to-back, comprising:
 if the pitch diameter of one of the two hybrid ball bearings is smaller or equal to 100 mm, the axial clearance is between −5 and 5 or 25 and 40 μm,   if the pitch diameter of one of the two hybrid ball bearings is greater than 100 mm and smaller than or equal to 200 mm, the axial clearance is between −5 and 20 μm, and   if the pitch diameter of one of the two hybrid ball bearings is greater than 200 mm, the axial clearance is between −5 and 30 μm.   
     
     
         10 . The two hybrid ball bearings according to  claim 9 , wherein the two hybrid ball bearings are in a not used, as new respectively not run in condition and are identical. 
     
     
         11 . The two hybrid ball bearings according to  claim 9 , wherein the two hybrid ball bearings are hybrid angular contact ball bearings with contact angles between 10 and 40°, particularly between 15 and 30°. 
     
     
         12 . The two hybrid ball bearings according to  claim 11 , wherein the contact angles of the two hybrid ball bearings are different, wherein particularly the contact angle of a first of the two hybrid ball bearings is between 10 to 20° and the contact angle of the second of the two hybrid ball bearings is between 21 to 35°. 
     
     
         13 . The two hybrid ball bearings according to  claim 9 , wherein at least one of the two hybrid ball bearings is configured for high rotation speeds between 2500 and 25000 rpm or nd m -values being between 500000 and 1200000 mm/60 s, wherein the nd m -value is the multiplication result of the rotation speed and the pitch diameter. 
     
     
         14 . The two hybrid ball bearings according to  claim 9 , wherein the two hybrid ball bearings are paired forming a synchronized set. 
     
     
         15 . A compressor bearing arrangement comprising:
 two hybrid ball bearings for a rotatable support of a rotor of the compressor versus a stator of the compressor, wherein   the two hybrid ball bearings are arranged face-to-face or back-to-back with following axial clearance with zero measuring and zero mounting loads, wherein   the axial clearance is between −5 and 5 or 25 and 40 μm, if an inner diameter of a ring-shaped inner raceway element of at least one of the two hybrid ball bearings is smaller or equal to 80 mm or if a pitch diameter of one of the two hybrid ball bearings is smaller or equal to 100 mm,   the axial clearance is between −5 and 20 μm, if an inner diameter of a ring-shaped inner raceway element of at least one of the two hybrid ball bearings is greater than 80 mm and smaller than or equal to 180 mm or if a pitch diameter of one of the two hybrid ball bearings is greater than 100 mm and smaller than or equal to 200 mm and,   the axial clearance is between −5 and 30 μm, if an inner diameter of a ring-shaped inner raceway element of at least one of the two hybrid ball bearings is greater than 180 mm or if a pitch diameter of one of the two hybrid ball bearings is greater than 200 mm.   
     
     
         16 . The compressor bearing arrangement according to  claim 15 , wherein the first of the two hybrid ball bearings comprises a first outer and a first inner ring-shaped raceway element and the second of the two hybrid ball bearings comprises a second outer and a second inner ring-shaped raceway element, and wherein at least one hollow-cylindrical distance element, particularly a lubrication spacer or distance ring, is provided being positioned between the two outer and/or the two inner raceway elements. 
     
     
         17 . The compressor bearing arrangement according to  claim 15 , wherein the two hybrid ball bearings are hybrid angular contact ball bearings with contact angles between 10 and 40°, particularly between 15 and 30°. 
     
     
         18 . The compressor bearing arrangement according to  claim 17 , wherein the contact angles of the two hybrid ball bearings are different, and wherein particularly the contact angle of a first of the two hybrid ball bearings is between 10 to 20° and the contact angle of the second of the two hybrid ball bearings is between 21 to 35°. 
     
     
         19 . The compressor bearing arrangement according to  claim 15 , wherein at least one of the two hybrid ball bearings is configured for high rotation speeds between 2500 and 25000 rpm or nd m -values being between 500000 and 1200000 mm/60 s, and wherein the nd m -value is the multiplication result of the rotation speed and the pitch diameter. 
     
     
         20 . The compressor bearing arrangement according to  claim 15 , wherein at least one of the two hybrid ball bearings is lubricated with an ultra-low viscosity lubricant, in particular a pure refrigerant or a refrigerant with a quantity of at least one other particularly lubrication-relevant substance of up to total of maximum 1%.