Scroll pump

Abstract

A non-contacting scroll pump, the non-contacting scroll pump comprising a housing, an orbiting scroll located within the housing, and a thrust bearing assembly located within the housing for axially supporting the orbiting scroll. The thrust bearing assembly comprises a first plate fixed to the orbiting scroll, a second plate spaced apart from the first plate, a ball bearing located between the first plate and the second plate, the ball bearing being configured to roll against the first and second plates during orbiting of the orbiting scroll. The thrust bearing assembly further comprises a coupling structure extending between the housing and the second plate to couple the housing to the second plate, wherein the coupling structure comprises a thermal break for reducing heat transfer from the second plate to the coupling structure during operation of the non-contacting scroll pump.

1 . A non-contacting scroll pump, the non-contacting scroll pump comprising:
 a housing;   an orbiting scroll located within the housing; and   a thrust bearing assembly located within the housing for axially supporting the orbiting scroll, wherein the thrust bearing assembly comprises:
 a first plate fixed to the orbiting scroll; 
   a second plate spaced apart from the first plate;   a ball bearing located between the first plate and the second plate, the ball bearing being configured to roll against the first and second plates during orbiting of the orbiting scroll; and   a coupling structure extending between the housing and the second plate to couple the housing to the second plate, wherein the coupling structure comprises a thermal break for reducing heat transfer from the second plate to the coupling structure during operation of the non-contacting scroll pump.   
     
     
         2 . The non-contacting scroll pump of  claim 1 , wherein the coupling structure comprises a pin comprising a hollow section, the hollow section extending axially from proximate to an end of the pin which is in contact with the second plate, and wherein the thermal break is provided at least partially by the hollow section. 
     
     
         3 . The non-contacting scroll pump of  claim 2 , wherein the pin has the same thermal expansion co-efficient as a section of the housing from which it extends. 
     
     
         4 . The non-contacting scroll pump of  claim 1 , wherein the coupling structure comprises one or more inserts located between the second plate and the rest of the coupling structure, wherein the thermal break is provided at least partially by the one or more inserts. 
     
     
         5 . The non-contacting scroll pump of  claim 1 , further comprising:
 a first ball bearing cage sandwiched between the first plate and the second plate; and   a second ball bearing cage sandwiched between the first plate and the second plate,   wherein the first and second ball bearing cages house the ball bearing to constrain movement of the ball bearing.   
     
     
         6 . The non-contacting scroll pump of  claim 5 , wherein the first ball bearing cage is fixed to the first plate and the second ball bearing cage is fixed to the second plate. 
     
     
         7 . The non-contacting scroll pump of  claim 5 , wherein the first and second ball bearing cages each comprise a hole, the hole of the first ball bearing cage overlapping with the hole of the second ball bearing cage, and
 wherein the ball bearing is accommodated within the overlapped holes of the ball bearing cages.   
     
     
         8 . The non-contacting scroll pump of  claim 1 , wherein the non-contacting scroll pump comprises three thrust bearing assemblies,
 wherein each of the three thrust bearing assemblies comprises:
 a first plate fixed to the orbiting scroll; 
   a second plate spaced apart from the first plate;   a ball bearing located between the first plate and the second plate, the ball bearing being configured to roll against the first and second plates during orbiting of the orbiting scroll; and
 a coupling structure extending between the housing and the second plate to couple the housing to the second plate, wherein the coupling structure comprises a thermal break for reducing heat transfer from the second plate to the coupling structure during operation of the non-contacting scroll pump, 
   wherein the three thrust bearing assemblies are evenly angularly distributed around the rotation axis of the orbiting scroll in a triangular formation.   
     
     
         9 . The non-contacting scroll pump of  claim 1 , wherein the coupling structure is for adjusting the axial position of the orbiting scroll. 
     
     
         10 . A vacuum pumping system comprising a plurality of vacuum pumps, wherein one of the vacuum pumps is the non-contacting scroll pump of  claim 1 . 
     
     
         11 . Use of the non-contacting scroll pump of  claim 1  to pump fluid.