Rotary fluid machine

Abstract

A rotary fluid machine is provided in which, among first bearings ( 23 f, 23 r ) and a second bearing ( 24 ) supporting in a casing ( 11 ) opposite ends of a rotor ( 22 ) that includes an axial piston cylinder group ( 56 ) for converting the pressure energy of a working medium into mechanical energy, only the first bearings ( 23 f, 23 r ) are formed from combined angular bearings that can support an axial load, and the second bearing ( 24 ) is formed from a radial bearing that can support a radial load and is axially movable relative to the rotor ( 22 ). Since the rotor ( 22 ) is axially positioned relative to the casing ( 11 ) by only the first bearings (the combined angular bearings) ( 23 f, 23 r ), a difference in the amount of axial thermal expansion between the casing ( 11 ) and the rotor ( 22 ) can be absorbed by the second bearing (radial bearing) ( 24 ) without any problem. This can solve effectively problems caused by a difference in the amount of thermal expansion between the casing and the rotor of the rotary fluid machine.

1 . A rotary fluid machine in which opposite ends of a rotor ( 22 ) are rotatably supported in a casing ( 11 ) via a first bearing ( 23   f ,  23   r ) and a second bearing ( 24 ), and energy conversion means for interconverting pressure energy of a working medium and mechanical energy of the rotating rotor ( 22 ) is provided in the rotor ( 22 ), 
 characterized in that among the first bearing ( 23   f ,  23   r ) and the second bearing ( 24 ), the axial load can be supported by only the first bearing ( 23   f ,  23   r ).    
     
     
         2 . The rotary fluid machine according to  claim 1 , wherein the rotary fluid machine is an expander (E), and the energy conversion means is an axial piston cylinder group ( 56 ).  
     
     
         3 . The rotary fluid machine according to  claim 1 , wherein the rotary fluid machine is provided with a rotary valve ( 71 ) for supplying and discharging the working medium to and from the rotor ( 22 ), the coefficient of thermal expansion of the rotor ( 22 ) is set so as to be substantially the same as the coefficient of thermal expansion of the first bearing ( 23   f ,  23   r ), the coefficient of thermal expansion of the casing ( 11 ) is set so as to be larger than the coefficient of thermal expansion of the rotor ( 22 ) and the coefficient of thermal expansion of the first bearing ( 23   f ,  23   r ), the first bearing ( 23   f ,  23   r ) is supported in the casing ( 11 ) via a bearing holder ( 99 ), and the coefficient of thermal expansion of the bearing holder ( 99 ) is set so as to be substantially the same as the coefficient of thermal expansion of the rotor ( 22 ) and the coefficient of thermal expansion of the first bearing ( 23   f ,  23   r ).  
     
     
         4 . The rotary fluid machine according to  claim 3 , wherein the rotary fluid machine is an expander (E), and the energy conversion means is an axial piston cylinder group ( 56 ) operated by a swash plate ( 31 ).  
     
     
         5 . The rotary fluid machine according to  claim 4 , wherein the swash plate ( 31 ) is supported in the casing ( 11 ) via a swash plate holder ( 28 ), and the coefficient of thermal expansion of the swash plate holder ( 28 ) is set so as to be substantially the same as the coefficient of thermal expansion of the bearing holder ( 99 ).  
     
     
         6 . The rotary fluid machine according to  claim 5 , wherein the swash plate holder ( 28 ) and the bearing holder ( 99 ) are formed from the same member.