Displacement detection device for variable displacement compressor

Abstract

A displacement detection device for a variable displacement compressor in which a swash plate which is connected to a piston through shoes in a housing slides relative to the shoes and rotates synchronously with a drive shaft with a wobbling motion in an axial direction of the drive shaft as the drive shaft is rotated, and an inclination angle of the swash plate is controlled thereby changing a stroke of the piston, includes a detection object provided in a first portion of an outer periphery of the swash plate where an imaginary plane passing through a point of intersection between a line connecting top and bottom dead center positions of the swash plate and an axial line of the drive shaft in perpendicular relation to the line intersects with the outer periphery of the swash plate and a detector provided in the housing so as to face the detection object.

1 . A displacement detection device for a variable displacement compressor in which a swash plate is connected to a piston through shoes in a housing, the swash plate slides relative to the shoes and rotates synchronously with a drive shaft with a wobbling motion in an axial direction of the drive shaft as the drive shaft is rotated, and an inclination angle of the swash plate is controlled thereby to change a stroke of the piston, comprising: 
 a detection object provided in a first portion of an outer periphery of the swash plate where an imaginary plane passing through a point of intersection between a line connecting a top dead center position and a bottom dead center position of the swash plate and an axial line of the drive shaft in perpendicular relation to the line intersects with the outer periphery of the swash plate; and    a detector provided in the housing so as to face the detection object.    
   
   
       2 . The displacement detection device according to  claim 1 , wherein the detector is located in a range between a minimum inclination angle position of the swash plate and a maximum inclination angle position of the swash plate.  
   
   
       3 . The displacement detection device according to  claim 1 , wherein the detection object is a magnet or a magnetic material.  
   
   
       4 . The displacement detection device according to  claim 3 , wherein the detector is a plurality of the magnetic sensors which are provided in a peripheral wall of the housing and aligned parallel to the axial line of the drive shaft.  
   
   
       5 . The displacement detection device according to  claim 3 , wherein the detector is a magnetic sensor.  
   
   
       6 . The displacement detection device according to  claim 5 , wherein the magnetic sensor is a Hall element, a magneto-inductive sensor, a magneto-resistive sensor or a magneto-impedance sensor.  
   
   
       7 . The displacement detection device according to  claim 1 , wherein the detection object and the detector are of ultrasound type or optical type.  
   
   
       8 . The displacement detection device according to  claim 1 , further comprising another detection object provided in a second portion of the outer periphery of the swash plate opposite to the first portion.  
   
   
       9 . The displacement detection device according to  claim 1 , wherein the housing includes a plurality of housing members which are joined to each other by a bolt, the detector being connected to the bolt.  
   
   
       10 . The displacement detection device according to  claim 1 , further including a fitting member which is provided to the housing, the detector being fixed to the fitting member.