Roller unit and rotary compressor

Abstract

A roller unit used for a rotary compressor is cylindrically formed to rotate eccentrically around a rotary shaft. The roller unit is divided into at least three rollers in an axial direction of the rotary shaft.

What is claimed is: 
     
         1 . A roller unit used for a rotary compressor, is cylindrically formed to rotate eccentrically around a rotary shaft, wherein
 the roller unit is divided into at least three rollers in an axial direction of the rotary shaft.   
     
     
         2 . The roller unit according to  claim 1 , wherein
 the at least three rollers comprise:   a first roller and a second roller arranged on both ends in the axial direction; and   a third roller sandwiched between the first roller and the second roller in the axial direction, and   when widths of each of the first roller, the second roller, and the third roller in the axial direction are L 1 , L 2 , and L 3 , L 3 >L 1  and L 3 >L 2  are satisfied.   
     
     
         3 . The roller unit according to  claim 2 , wherein L 1 =L 2  is satisfied. 
     
     
         4 . The roller unit according to  claim 3 , wherein the widths L 1  and L 2  of each of the first roller and the second roller are equal to or greater than a minimum width calculated from a Sommerfeld number and a Gumbel boundary condition of an infinitely short bearing. 
     
     
         5 . The roller unit according to  claim 1 , wherein at least one roller of the at least three rollers has a plurality of grooves that are arranged on a side surface adjacent to another roller of the at least three rollers and that extend radially from the rotary shaft. 
     
     
         6 . The roller unit according to  claim 5 , wherein the plurality of grooves are arranged along a direction in which a lubricant is pushed out towards an outer peripheral direction of the roller by a rotation of the roller. 
     
     
         7 . The roller unit according to  claim 5 , wherein the plurality of grooves communicate with a centrum of the cylindrical roller, and do not communicate with an outer peripheral surface of the roller. 
     
     
         8 . The roller unit according to  claim 5 , wherein the plurality of grooves communicate with a centrum of the cylindrical roller, and communicate with an outer peripheral surface of the roller. 
     
     
         9 . The roller unit according to  claim 5 , wherein
 on the side surface of one roller of the at least three rollers, the plurality of grooves communicate with a centrum of the cylindrical roller, and do not communicate with an outer peripheral surface of the roller, and   on the side surface of another roller adjacent to the side surface of the one roller, the plurality of grooves communicate with an outer peripheral surface of the another roller, without communicating with a centrum of the another cylindrical roller.   
     
     
         10 . A rotary compressor comprising:
 an electric motor part;   a compression mechanism part that is driven by the electric motor part; and   a sealed casing that accommodates the electric motor part and the compression mechanism part, wherein   the electric motor part comprises:
 a motor rotor that is rotary driven; and 
 a rotary shaft that is rotated by the rotary drive of the motor rotor, and 
   the compression mechanism part comprises:
 a cylinder comprising a cylinder chamber; 
 a roller unit that is arranged in the cylinder chamber in a state of being fitted to the rotary shaft, that is cylindrically formed to rotate eccentrically in the cylinder chamber along with an eccentric rotation of the rotary shaft, and that is divided into at least three rollers in an axial direction of the rotary shaft; and 
 a blade that is pushed in a direction that abuts an outer peripheral surface of the roller unit, comprises a distal end portion that abuts the outer peripheral surface by being pushed, and partitions the cylinder chamber into a suction chamber and a compression chamber in a state where the distal end portion abuts the outer peripheral surface. 
   
     
     
         11 . The rotary compressor according to  claim 10 , wherein the at least three rollers comprise:
 a first roller and a second roller that are arranged on both ends in the axial direction; and   a third roller sandwiched between the first roller and the second roller in the axial direction, wherein   when widths of each of the first roller, the second roller, and the third roller in the axial direction are L 1 , L 2 , and L 3 , L 3 >L 1  and L 3 >L 2  are satisfied.   
     
     
         12 . The rotary compressor according to  claim 11 , wherein L 1 =L 2  is satisfied. 
     
     
         13 . The rotary compressor according to  claim 12 , wherein the widths L 1  and L 2  of each of the first roller and the second roller are equal to or greater than a minimum width calculated from a Sommerfeld number and a Gumbel boundary condition of an infinitely short bearing. 
     
     
         14 . The rotary compressor according to  claim 10 , wherein at least one roller of the at least three rollers has a plurality of grooves that are arranged on a side surface adjacent to another roller of the at least three rollers, and that extend radially from the rotary shaft. 
     
     
         15 . The rotary compressor according to  claim 14 , wherein the plurality of grooves are arranged along a direction in which a lubricant is pushed out towards an outer peripheral direction of the roller by a rotation of the roller. 
     
     
         16 . The rotary compressor according to  claim 14 , wherein the plurality of grooves communicate with a centrum of the cylindrical roller, and do not communicate with an outer peripheral surface of the roller. 
     
     
         17 . The rotary compressor according to  claim 14 , wherein the plurality of grooves communicate with a centrum of the cylindrical roller and an outer peripheral surface of the roller. 
     
     
         18 . The rotary compressor according to  claim 14 , wherein
 on the side surface of one roller of the at least three rollers, the plurality of grooves communicate with a centrum of the cylindrical roller, and do not communicate with an outer peripheral surface of the roller, and   on the side surface of another roller adjacent to the side surface of the one roller, the plurality of grooves communicate with an outer peripheral surface of the another roller, without communicating with a centrum of the another cylindrical roller.