Hermetic screw compressor

Abstract

A hermetic screw compressor comprises a male rotor, a female rotor engaging the male rotor, an electric motor connected to a low pressure side shaft portion of the male rotor, a low pressure side bearing for supporting the low pressure side shaft portion of each of the rotors, a high pressure side bearing for supporting a high pressure side shaft portion of each of the rotors, and a casing containing the rotors, the electric motors and the bearings. A contact type seal is arranged to seal a part of the low pressure side shaft portion of the male rotor between the low pressure side bearing and the electric motor, and a cover contains the seal and is axially detachably attached to the casing so that the contact type seal is attached to the casing through the cover.

1 . A hermetic screw compressor comprising,
 screw rotors each of which includes a teeth portion, a low pressure side shaft portion and a high pressure side shaft portion,   an electric motor connected to the low pressure side shaft portion of at least one of the screw rotors,   a low pressure side bearing for supporting the low pressure side shaft portion,   a high pressure side bearing for supporting the high pressure side shaft portion, and   a casing containing hermetically the screw rotors, the electric motor, the low pressure side bearing and the high pressure side bearing,   wherein the compressor further comprises a contact type seal arranged to seal a part of the screw rotor between the electric motor and the low pressure side bearing at the low pressure side shaft portion, and a cover containing the contact type seal and detachably attached to the casing.   
   
   
       2 . The hermetic screw compressor according to  claim 1 , wherein the screw rotor has a sleeve forming the part of the screw rotor with which the contact type seal contacts, and a hardness of the sleeve is higher than a hardness of the low pressure side shaft portion. 
   
   
       3 . The hermetic screw compressor according to  claim 1 , wherein the screw rotors includes a pair of male and female rotors engaging each other. 
   
   
       4 . The hermetic screw compressor according to  claim 1 , wherein the screw rotors includes a pair of screw rotor and gate roller engaging each other. 
   
   
       5 . A hermetic screw compressor comprising,
 a screw rotor including a teeth portion of screw shape, and a rotor shaft monolithic with the teeth portion,   an electric motor connected to the rotor shaft to be rotationally driven,   a low pressure side bearing for supporting an intake side of the rotor shaft,   a high pressure side bearing for supporting an exit side of the rotor shaft, and   a casing containing the screw rotor, the electric motor, the low pressure side bearing and the high pressure side bearing,   wherein the compressor further comprises a contact type seal arranged to seal the rotor shaft between the low pressure side bearing and the electric motor, and a bearing holder for holding the low pressure side bearing axially with respect to the casing, the bearing holder containing the contact type seal so that the contact type seal is attached to the casing through the bearing holder.   
   
   
       6 . The hermetic screw compressor according to  claim 5 , wherein the rotor shaft has a sleeve on which the contact type seal slides, and a hardness of the sleeve is higher than a remainder part of the rotor shaft. 
   
   
       7 . A hermetic screw compressor comprising,
 a male rotor, a female rotor engaging the male rotor, an electric motor connected to a low pressure side shaft portion of the male rotor, a low pressure side bearing for supporting the low pressure side shaft portion of each of the rotors, a high pressure side bearing for supporting a high pressure side shaft portion of each of the rotors, and a casing containing the rotors, the electric motors and the bearings,   wherein the compressor further comprises a contact type seal arranged to seal a part of the low pressure side shaft portion of the male rotor between the low pressure side bearing and the electric motor, and a cover containing the seal and axially detachably attached to the casing so that the contact type seal is attached to the casing through the cover, the low pressure side shaft portion has a sleeve arranged to slide with respect to the contact type seal, and a hardness of the sleeve is higher than a hardness of a remainder part of the low pressure side shaft portion.   
   
   
       8 . The hermetic screw compressor according to  claim 7 , wherein the low pressure side shaft portion and the high pressure side shaft portion are monolithically included by each of the rotors, and the low pressure side shaft portion of the male rotor is directly connected to the electric motor to be rotationally driven. 
   
   
       9 . The hermetic screw compressor according to  claim 1 , wherein the contact type seal is an oil seal. 
   
   
       10 . The hermetic screw compressor according to  claim 1 , wherein the contact type seal is a mechanical seal.