Control Device for a Vehicular Refrigeration, Vehicular Variable Displacement Compressor, and A Control Valve for the Vehicular Variable Displacement Compressor

Abstract

Provided is a control valve of a vehicular refrigeration circuit, including: an air supply passage for communicating a discharge chamber and a crank chamber with each other; a second rod capable of changing a primary opening which is the degree of opening of the air supply passage; a first bellows which moves while causing a first load F 1 due to a differential pressure ΔPd between a high discharge pressure PdH and a low discharge pressure PdL to operate the second rod such that the primary opening increases or decreases; a constant pressure valve for maintaining the low discharge pressure PdL in a high pressure chamber communicating with the discharge chamber at a constant correction pressure PdL 0 ; an actuator capable of changing the correction pressure PdL 0 to a predetermined control pressure PdLx due to energization control by a controller; and a second bellows which moves while causing a second load F 2 opposing the first load F 1 with the control pressure PdLx to adjust the primary opening.

1 . A control device for a vehicular refrigeration circuit used together with a variable displacement compressor, having a crank chamber, an intake chamber, and a discharge chamber, in which discharge capacity can be changed by controlling a pressure of the crank chamber, and with an exterior refrigerant circulation circuit connected to the intake chamber and the discharge chamber of the variable displacement compressor, the control device comprising: 
 a bleed passage for communicating the intake chamber and the crank chamber with each other;    an air supply passage for communicating the discharge chamber and the crank chamber with each other;    a primary valve mechanism capable of changing a primary opening which is a degree of opening of at least one of the bleed passage and the air supply passage;    a first pressure sensing member which moves while causing a first load due to a state pressure which is a pressure having a factor for controlling the discharge capacity to operate the primary valve mechanism so that the primary opening increases or decreases;    a constant pressure valve mechanism for maintaining a high pressure in a high pressure chamber, which communicates with the discharge chamber, to be a constant correction pressure;    a secondary valve mechanism capable of changing the correction pressure to a predetermined control pressure by external energization control; and    a second pressure sensing member which moves while causing due to the control pressure a second load opposing the first load to correct the primary opening.    
   
   
       2 . A control device for a vehicular refrigeration circuit according to  claim 1 , further comprising: 
 a state pressure chamber communicating with the discharge chamber through a state pressure passage; and    a differential pressure generating mechanism provided in the state pressure passage, for causing the state pressure to be turned into a first state pressure and a second state pressure having a difference therebetween,    wherein the first pressure sensing member is provided in the state pressure chamber, and moves due to a differential pressure between the first state pressure and the second state pressure while causing the first load.    
   
   
       3 . A control device for a vehicular refrigeration circuit according to  claim 2 , wherein: 
 the state pressure chamber is a first pressure sensing chamber which accommodates the first pressure sensing member, to which one of the first state pressure and the second state pressure is introduced, and which constitutes a part of the air supply passage; and    the first pressure sensing member is a bellows which includes therein a first control chamber to which the other of the first state pressure and the second state pressure is introduced.    
   
   
       4 . A control device for a vehicular refrigeration circuit according to  claim 1 , further comprising a second pressure sensing chamber accommodating the second pressure sensing member and constituting a part of the air supply passage, 
 wherein the second pressure sensing member is a bellows including therein a second control chamber to which the control pressure is introduced.    
   
   
       5 . A control device for a vehicular refrigeration circuit according to  claim 1 , wherein the secondary valve mechanism comprises: 
 a high pressure passage for communicating the discharge chamber and the second control chamber with each other;    a release passage for communicating the second control chamber and the air supply passage with each other; and    an actuator operated by controlling energization with respect thereto from outside and capable of changing a secondary opening which is a degree of opening of the release passage.    
   
   
       6 . A control device for a vehicular refrigeration circuit according to  claim 1 , wherein the secondary valve mechanism comprises: 
 a high pressure passage for communicating the discharge chamber and the second control chamber with each other; and    an actuator operated by controlling energization with respect thereto from outside and capable of changing a secondary opening which is a degree of opening of the high pressure passage.    
   
   
       7 . A control device for a vehicular refrigeration circuit according to  claim 5 , wherein the actuator comprises a piezoelectric element.  
   
   
       8 . A control device for a vehicular refrigeration circuit according to  claim 7 , further comprising a controller for controlling a duty ratio of a voltage to be applied to the piezoelectric element.  
   
   
       9 . A variable displacement compressor, comprising: 
 a housing including a cylinder bore, a crank chamber, an intake chamber, and a discharge chamber formed therein;    a piston reciprocatingly accommodated in the cylinder bore, for defining a compression chamber in the cylinder bore;    a drive shaft driven by an exterior drive source and rotatably supported by the housing;    a swash plate supported in the crank chamber so that the swash plate can rotate in synchronism with the drive shaft and can be inclined, for allowing the piston to be reciprocatingly driven; and    a control mechanism for controlling a pressure in the crank chamber, capable of changing an inclination angle of the swash plate to change a discharge capacity, the intake chamber and the discharge chamber being connected to an exterior refrigerant circulation circuit to constitute a vehicular refrigeration circuit,    wherein the control mechanism is the control device according to  claim 1 .    
   
   
       10 . A control valve for the variable displacement compressor according to  claim 9 , comprising: 
 a valve housing fixed to the housing;    the air supply passage and the high pressure chamber formed in the valve housing; and    the primary valve mechanism, the first pressure sensing member,the constant pressure valve mechanism, the secondary valve mechanism, and the second pressure sensing member provided in the valve housing.