Swash plate type variable displacement compressor

Abstract

A variable displacement compressor includes a swash plate guiding member that rotates integrally with and inclines relative to a drive shaft, a swash plate supported by the guiding member, and a piston engaged with the swash plate via a shoe. A clutch is located between the guiding member and the swash plate. The clutch is switched between an engaged state, where the clutch permits the guiding member and the swash plate to rotate integrally, and a disengaged state, where the clutch permits the guiding member and the swash plate to rotate relative to each other. Therefore, the compressor is capable of switching between a state where improving the displacement controllability is prioritized and a state where reduction of mechanical loss between the swash plate and the shoes is prioritized.

1 . A swash plate type variable displacement compressors comprising: 
 a drive shaft;    a swash plate guiding member that is coupled to the drive shaft, wherein the guiding member rotates integrally with and inclines relative to the drive shaft;    a swash plate supported by the guiding member;    a shoe;    a piston engaged with the swash plate via the shoe, wherein, when the guiding member is rotated by rotation of the drive shaft, the piston reciprocates to compress gas, and wherein, when an inclination angle of the swash plate relative to the drive shaft is changed as the guiding member inclines, the stroke of the piston is changed to vary the displacement of the compressor; and    a clutch located between the guiding member and the swash plate, wherein the clutch is switched between an engaged state, where the clutch permits the guiding member and the swash plate to rotate integrally, and a disengaged state, where the clutch permits the guiding member and the swash plate to rotate relative to each other.    
   
   
       2 . The compressor according to  claim 1 , wherein the swash plate is supported by the guiding member to be slidable along a central axis of the swash plate, 
 wherein, when the swash plate slides relative to the guiding member in one direction along the central axis, the clutch is switched from the disengaged state to the engaged states and    wherein, when the swash plate slides relative to the guiding member in the other direction along the central axis, the clutch is switched from the engaged state to the disengaged state.    
   
   
       3 . The compressor according to  claim 2 , wherein the guiding member has a boss, wherein a boss receiving hole is formed in a central portion of the swash plate, and wherein the swash plate is supported by the boss at the boss receiving hole such that the swash plate is rotatable around the central axis and is slidable in directions along the central axis.  
   
   
       4 . The compressor according to  claim 3 , wherein the boss has a slide limiter that limits sliding of the swash plate in a direction along the central axis, and 
 wherein, when the clutch has been switched from the engaged state to the disengaged state, the slide limiter contacts the swash plate to limit sliding of the swash plate in a direction away from a position corresponding to the engaged state.    
   
   
       5 . The compressor according to  claim 2 , wherein the swash plate is slid by compression reaction force acting on the swash plate through the piston as the gas is compressed so that the clutch is switched from the disengaged state to the engaged state.  
   
   
       6 . The compressor according to  claim 2 , wherein a spring is located between the guiding member and the swash plate, and 
 wherein the swash plate is slid by the force of the spring so that the clutch is switched from the engaged state to the disengaged state.    
   
   
       7 . The compressor according to  claim 1 , wherein a bearing is located between the guiding member and the swash plate, the bearing supporting the swash plate to be rotatable relative to the guiding member.  
   
   
       8 . The compressor according to  claim 4 , wherein a thrust bearing is located between the swash plate and the slide limiter, the thrust bearing supporting the swash plate to be rotatable relative to the slide limiter when the clutch is in the disengaged state.  
   
   
       9 . The compressor according to  claim 2 , wherein a spring is located between the guiding member and the swash plate, wherein the swash plate is slid by the force of the spring so that the clutch is switched from the engaged state to the disengaged state, and 
 wherein a thrust bearing is located in a space between the spring and one of the guiding member and the swash plate that rotates relative to the spring when the clutch is in the disengaged state, the thrust bearing supporting the swash plate to be rotatable relative to the guiding member.    
   
   
       10 . The compressor according to  claim 6 , wherein the swash plate has a top dead center portion that locates the piston at the top dead center, wherein the spring is arranged to apply the force to the top dead center portion on the swash plate around the central axis in a concentrated manner.  
   
   
       11 . The compressor according to  claim 2 , wherein a radial bearing is located between the guiding member and the swash plate, the radial bearing supporting the swash plate to be rotatable relative to the guiding member around the central axis and to be slidable in directions along the central axis.  
   
   
       12 . The compressor according to  claim 1 , wherein the clutch comprising a driving clutch surface formed on the guiding member and a driven clutch surface formed on the swash plate, and when the driving clutch surface contacts the driven clutch surface, the clutch is in the engaged state.  
   
   
       13 . The compressor according to  claim 3 , wherein the clutch comprises a driving clutch surface formed on the guiding member and a driven clutch surface formed on the swash plate, and when the driving clutch surface contacts the driven clutch surface, the clutch is in the engaged state, and 
 wherein the driving clutch surface is formed on an outer circumferential surface of the boss, and the driven clutch surface is formed on an inner circumferential surface of the boss receiving hole.    
   
   
       14 . The compressor according to  claim 3 , wherein the clutch comprising a driving clutch surface formed on the guiding member and a driven clutch surface formed on the swash plate, and when the driving clutch surface contacts the driven clutch surface, the clutch is in the engaged state, and 
 wherein the driving clutch surface and the driven clutch surface are located outside the boss receiving hole.    
   
   
       15 . The compressor according to  claim 12 , wherein the clutch is in the engaged state when the driving clutch surface contacts the driven clutch surface.  
   
   
       16 . The compressor according to  claim 15 , wherein the driving clutch surface and the driven clutch surface are conical.  
   
   
       17 . The compressor according to  claim 12 , wherein projections are formed on the driving clutch surface and the driven clutch surface, and wherein the clutch is in the engaged state when the driving surface and the driven clutch surface are meshed with each other.  
   
   
       18 . The compressor according to  claim 1 , further comprising: 
 cm an oil supply portion that supplies lubricant oil to a space between the guiding member and the swash plate when the guiding member and the swash plate rotate relative to each other.    
   
   
       19 . The compressor according to  claim 15 , further comprising: 
 an oil supply portion that supplies lubricant oil to a space between the driving clutch surface and the driven clutch surface when the guiding member and the swash plate rotate relative to each other.    
   
   
       20 . The compressor according to  claim 3 , further comprising: 
 an oil supply portion that supplies lubricant oil to a space between an outer circumferential surface of the boss and an inner circumferential surface of the boss receiving hole when the guiding member and the swash plate rotate relative to each other.    
   
   
       21 . The compressor according to  claim 20 , wherein the oil supply portion includes an oil supply hole formed in the guiding member, the oil supply hole having an outlet and an inlet of lubricant oil, and wherein the outlet is connected to the outer circumferential surface of the boss, and the inlet is located at a position that is closer to the drive shaft than the outlet.  
   
   
       22 . The compressor according to  claim 21 , wherein the oil supply portion includes a reservoir groove that is formed on at least one of the outer circumferential surface of the boss and the inner circumferential surface of the boss receiving hole, and 
 wherein the reservoir groove extends in a direction along the central axis, and is connected to the outlet of the oil supply hole.    
   
   
       23 . The compressor according to  claim 1 , further comprising: 
 a first rotation speed sensor for detecting a rotation speed of the swash plate,    a second rotation speed sensor for detecting a rotation speed of the guiding member,    a slip judging portion that judges whether the rotation speed of the swash plate is lower than the rotation speed of the guiding member when the clutch is in the engaged state, and    a clutch controller that switches the clutch to the disengaged state when the result of judgment of the slip judging portion is positive.    
   
   
       24 . The compressor according to claims  1 , further comprising: 
 a swash plate rotation speed sensor for detecting a rotation speed of the swash plate,    an abnormality judging portion that judges whether the rotation speed of the swash plate is more than a predetermined reference rotation speed when the clutch is in the disengaged state, and    a memory portion that stores an occurrence of abnormality when the result of judgment of the abnormality judging portion is positive.    
   
   
       25 . A swash plate type variable displacement compressor, comprising: 
 a drive shaft;    a swash plate guiding member that is coupled to the drive shaft, wherein the guiding member rotator integrally with and inclines relative to the drive shaft;    a swash plate supported by the guiding member;    a shoe;    a piston engaged with the swash plate via the shoe, wherein, when the guiding member is rotated by rotation of the drive shaft, the piston reciprocates to compress gas, and wherein, when an inclination angle of the swash plate relative to the drive shaft is changed as the guiding member inclines, the stroke of the piston is changed to vary the displacement of the compressor; and    a clutch located between the guiding member and the swash plate, wherein the clutch is switched between an engaged state, where the clutch permits the guiding member and the swash plate to rotate integrally, and a disengaged state, where the clutch permits the guiding member and the swash plate to rotate relative to each other,    wherein the swash plate is supported by the guiding member to be slidable along a central axis of the swash plate, wherein, when the swash plate slides relative to the guiding member in one direction along the central axis, the clutch is switched from the disengaged state to the engaged state, wherein, when the swash plate slides relative to the guiding member in the other direction along the central axis, the clutch is switched from the engaged state to the disengaged state,    wherein the swash plate is slid by compression reaction force acting on the swash plate through the piston as the gas is compressed so that the clutch is switched from the disengaged state to the engaged state,    wherein a spring is located between the guiding member and the swash plate, and wherein the swash plate is slid by the force of the spring so that the clutch is switched from the engaged state to the disengaged state,    wherein a thrust bearing is located in a space between the spring and one of the guiding member and the swash plate that rotates relative to the spring when the clutch is in the disengaged state, the thrust bearing supporting the swash plate to be rotatable relative to the guiding member, and    wherein the swash plate has a top dead center portion that locates the piston at the top dead center, wherein the spring is arranged to apply the force to the top dead center portion on the swash plate around the central axis in a concentrated manner.