Variable displacement swash plate compressor

Abstract

The variable displacement swash plate compressor includes a housing, a drive shaft, a swash plate, a piston, a bleed passage, a supply passage and a low-melting member. The housing has a cylinder bore, a suction chamber, a discharge chamber and a crank chamber. The swash plate is supported in the crank chamber by the drive shaft and inclination angle of the swash plate is adjustable. The piston is reciprocally movably received in the cylinder bore. The bleed passage is formed in the housing in communication with the crank chamber and the suction chamber. The supply passage is formed in the housing in communication with the discharge chamber and the crank chamber. The low-melting member is disposed in the bleed passage so as to restrict fluid flow therethrough and has a lower melting point than the housing. When the low-melting member is melted, an opening of the bleed passage is increased.

1 . A variable displacement swash plate compressor comprising:
 a housing having therein a cylinder bore, a suction chamber, a discharge chamber and a crank chamber, wherein the cylinder bore is communicable with the suction chamber and the discharge chamber;   a drive shaft rotatably supported by the housing and extending through the crank chamber;   a swash plate supported in the crank chamber by the drive shaft, inclination angle of the swash plate being adjustable;   a piston reciprocally movably received in the cylinder bore;   a bleed passage formed in the housing in communication with the crank chamber and the suction chamber;   a supply passage formed in the housing in communication with the discharge chamber and the crank chamber; and   a low-melting member disposed in the bleed passage so as to restrict fluid flow therethrough, the low-melting member having a lower melting point than the housing, wherein when the low-melting member is melted, an opening of the bleed passage is increased.   
     
     
         2 . The variable displacement swash plate compressor according to  claim 1 , wherein the bleed passage includes a first bleed passage and a second bleed passage, wherein the first bleed passage is in constant communication with the crank chamber and the suction chamber, and wherein the second bleed passage is closed by the low-melting member when temperature in the crank chamber is less than the melting point of the low-melting member. 
     
     
         3 . The variable displacement swash plate compressor according to  claim 1 , wherein the low-melting member being provided with a throttling portion in the bleed passage for restricting the fluid flow. 
     
     
         4 . The variable displacement swash plate compressor according to  claim 1 , further comprising:
 a displacement control valve provided in the supply passage;   a valve hole formed in the housing; and   a spool valve disposed in the valve hole for adjusting of the fluid flow through the bleed passage, the spoof valve partitioning the valve hole into two chambers, one chamber of which forms part of the bleed passage and is communicable with the suction chamber, the other chamber of which communicates with the supply passage at a position downstream of the displacement control valve, wherein the low-melting member is the spool valve.   
     
     
         5 . The variable displacement swash plate compressor according to  claim 2 , wherein the second bleed passage is provided in a plurality, wherein the plural second bleed passages respectively have therein a plurality of the low-melting members having different melting points thereamong. 
     
     
         6 . The variable displacement swash plate compressor according to  claim 1 , wherein the bleed passage has a large-diameter portion that is formed at a position downstream of the low-melting member, wherein a diameter of the large-diameter portion is greater than a diameter of a portion where the low-melting member is disposed. 
     
     
         7 . The variable displacement swash plate compressor according to  claim 6 , wherein the large-diameter portion has a larger diameter than a diameter of a spherical body having the same volume as the low-melting member. 
     
     
         8 . The variable displacement swash plate compressor according to  claim 1 , wherein the low-melting member is inserted in the bleed passage at a position connected to the crank chamber. 
     
     
         9 . The variable displacement swash plate compressor according to  claim 1 , wherein when mass of the whole low-melting member is 100%, the low-melting member contains zinc of not less than 7.5% by mass but not more than 12.0% by mass, indium of not less than 6.0% by mass but not more than 12.0% by mass and the remainders being tin and inevitable impurities. 
     
     
         10 . The variable displacement swash plate compressor according to  claim 9 , wherein the low-melting member contains indium of not more than 10.0% by mass. 
     
     
         11 . The variable displacement swash plate compressor according to  claim 3 , wherein the bleed passage has therein a receiver at a position that is closer to the suction chamber than the low-melting member for receiving the molten low-melting member. 
     
     
         12 . The variable displacement swash plate compressor according to  claim 11 , wherein the receiver is a recess that recedes downward from an inner peripheral surface of the bleed passage. 
     
     
         13 . The variable displacement swash plate compressor according to  claim 12 , further comprising an absorber disposed in the recess for absorbing the molten low-melting member. 
     
     
         14 . The variable displacement swash plate compressor according to  claim 11 , wherein the receiver is a band-like absorber that extends across the bleed passage at a position that is closer to the suction chamber than the low-melting member for absorbing the molten low-melting member.