Turbomachine and refrigeration cycle apparatus

Abstract

A turbomachine for a refrigeration cycle apparatus that uses a refrigerant whose saturated vapor pressure is a negative pressure at ordinary temperature includes a rotation shaft and a bearing for supporting the rotation shaft. The rotation shaft includes a lubricant supply passage for supplying the refrigerant as a lubricant that travels smoothly between the rotation shaft and the bearing. The lubricant supply passage includes a main passage and a sub-passage. The main passage extends from an inlet located at an end of the rotation shaft in an axial direction of the rotation shaft. The sub-passage diverges from the main passage and extends to an outlet located in a side surface of the rotation shaft.

What is claimed is: 
     
         1 . A turbomachine for a refrigeration cycle apparatus that uses a refrigerant whose saturated vapor pressure is a negative pressure at ordinary temperature, the turbomachine comprising:
 a rotation shaft; and   a bearing that supports the rotation shaft, wherein   the rotation shaft includes a lubricant supply passage containing
 a main passage that extends from an inlet located at an end of the rotation shaft in an axial direction of the rotation shaft, and 
 one or more sub-passages that diverge from the main passage and that extend to an outlet located in a side surface of the rotation shaft, and 
   while the rotation shaft rotates, the lubricant supply passage supplies the refrigerant to a portion where is located between the rotation shaft and the bearing.   
     
     
         2 . The turbomachine according to  claim 1 , wherein
 the sub-passage intersects a central axis of the main passage and extends along a straight line perpendicular to the central axis.   
     
     
         3 . The turbomachine according to  claim 1 , wherein
 the outlet of the sub-passage is located at a more backward position in a direction of rotation of the rotation shaft than a point at which a straight line intersects the side surface of the rotation shaft, the straight line connecting a central axis of the main passage and a center of an opening of the sub-passage on a side of the main passage.   
     
     
         4 . The turbomachine according to  claim 1 , wherein
 when the sub-passage is viewed in an axial direction of the rotation shaft, the sub-passage is expanded backward in a direction of rotation of the rotation shaft from a position in the sub-passage to the outlet, the position being located between an opening of the sub-passage on a side of the main passage and the outlet.   
     
     
         5 . The turbomachine according to  claim 1 , wherein
 the lubricant supply passage includes the plurality of sub-passages arranged in the axial direction of the rotation shaft.   
     
     
         6 . The turbomachine according to  claim 1 , wherein
 when the sub-passage is viewed from a direction perpendicular to the axial direction of the rotation shaft, a central axis of the sub-passage is tilted with respect to a central axis of the main passage in the axial direction of the rotation shaft.   
     
     
         7 . The turbomachine according to  claim 1 , further comprising:
 a storage portion that adjoins the bearing on a side of the inlet and stores the refrigerant as the lubricant, wherein   the inlet located at the end of the rotation shaft is soaked in the refrigerant stored in the storage portion as the lubricant.   
     
     
         8 . A refrigeration cycle apparatus comprising:
 a main circuit that circulates a refrigerant whose saturated vapor pressure is a negative pressure at ordinary temperature, the main circuit including
 an evaporation mechanism that stores a refrigerant liquid and evaporates the refrigerant liquid, 
 an turbomachine according to  claim 1 , and 
 a condensation mechanism that condenses refrigerant vapor and stores a refrigerant liquid, the evaporation mechanism, the turbomachine, and the condensation mechanism being connected in named order; 
   an evaporation-side circulation circuit that includes a heat-absorption-side liquid carrying pump and a heat-absorption heat exchanger, the heat-absorption-side liquid carrying pump causing the refrigerant liquid stored in the evaporation mechanism to be supplied to the heat-absorption heat exchanger, the refrigerant after heat absorption in the heat-absorption heat exchanger being returned to the evaporation mechanism;   a condensation-side circulation circuit that includes a heat-radiation-side liquid carrying pump and a heat-radiation heat exchanger, the heat-radiation-side liquid carrying pump causing the refrigerant liquid stored in the condensation mechanism to be supplied to the heat-radiation heat exchanger, the refrigerant after heat radiation in the heat-radiation heat exchanger being returned to the condensation mechanism; and   an upstream-side supply passage that diverges from the evaporation-side circulation circuit at a position downstream of an exit of the heat-absorption-side liquid carrying pump in the evaporation-side circulation circuit or diverges from the condensation-side circulation circuit at a position downstream of an exit of the heat-radiation-side liquid carrying pump in the condensation-side circulation circuit, and supplies the refrigerant to the lubricant supply passage.