Refrigerant suction structure in fixed displacement type piston compressor, and operation control method in fixed displacement type piston compressor

Abstract

An introduction passage of rotary valve has outlets for feeding out refrigerant in a suction pressure zone toward each of compression chambers. A switch portion in a shutoff state shuts off a portion of the suction pressure zone within a compressor from the outlets of the introduction passage. The switch portion includes a valve body, a working pressure chamber, and a working pressure applying portion. The working pressure chamber introduces a working pressure that is applied to the valve body so as to arrange the valve body at a communication position. The pressure in the suction pressure zone acts against the pressure in the working pressure chamber through the valve body.

1 . A refrigerant suction structure in a fixed displacement type piston compressor, wherein the compressor comprises:
 a rotary shaft coupled to an external drive source via a clutch;   a plurality of cylinder bores arranged around the rotary shaft;   a plurality of pistons defining compression chambers in the cylinder bores by being respectively accommodated in the cylinder bores;   a cam body integrated with the rotary shaft, the cam body converting a rotation of the rotary shaft into reciprocation of each of the pistons;   a suction pressure zone; and   a rotary valve having an introduction passage for introducing a refrigerant from the suction pressure zone to each of the compression chambers, the rotary valve integrally rotating with the rotary shaft, the suction pressure zone having a portion within the compressor, and the introduction passage having outlets for feeding out the refrigerant toward each of the compression chambers,   wherein the refrigerant suction structure has a switch portion capable of being switched between a communication state and a shutoff state,   wherein the switch portion in the communication state allows the portion of the suction pressure zone within the compressor to communicate with the outlets of the introduction passage,   wherein the switch portion in the shutoff state shuts off the portion of the suction pressure zone within the compressor from the outlets of the introduction passage,   wherein the switch portion includes:   a valve body capable of being switched between a communication position and a shutoff position, the valve body in the communication position allowing the portion of the suction pressure zone within the compressor to communicate with the outlets of the introduction passage, and the valve body in the shutoff position shutting off the portion of the suction pressure zone within the compressor from the outlets of the introduction passage;   a working pressure chamber introducing a working pressure that is applied to the valve body so as to arrange the valve body at the communication position; and   a working pressure applying portion applying the working pressure to the working pressure chamber, and   wherein the pressure in the suction pressure zone acts against the pressure in the working pressure chamber through the valve body.   
   
   
       2 . The refrigerant suction structure according to  claim 1 , wherein the switch portion has a working pressure recess, and the valve body is slidably fitted into the working pressure recess, whereby the valve body defines the working pressure chamber within the working pressure recess,
 wherein the pressure of the portion of the suction pressure zone within the compressor acts against the pressure of the working pressure chamber via the valve body, and   wherein the switch portion is provided with a first return spring for returning the valve body to the shutoff position from the communication position.   
   
   
       3 . The refrigerant suction structure according to  claim 2 , wherein the introduction passage has an inlet for accepting the refrigerant from the suction pressure zone, and
 wherein, in the case that the switch portion is in the shutoff state, the valve body is arranged in such a manner as to shut off the inlet of the introduction passage from the portion of the suction pressure zone within the compressor.   
   
   
       4 . The refrigerant suction structure according to  claim 3 , wherein the inlet of the introduction passage is positioned in an end surface of the rotary valve, and the outlets of the introduction passage are positioned in a peripheral surface of the rotary valve,
 wherein a rotation axis of the rotary valve intersects the end surface,   wherein the refrigerant suction structure comprises:   a valve accommodation chamber rotatably accommodating the rotary valve; and   a guide cylinder surrounding the rotation axis outside the valve accommodation chamber,   wherein a cylinder interior of the guide cylinder communicates with an inlet of the introduction passage,   wherein the valve body is slidably fitted to the guide cylinder, the valve body has an internal passage communicating with the cylinder interior of the guide cylinder, and the internal passage has an inlet for accepting the refrigerant from the suction pressure zone,   wherein, in the case that the valve body exists at the shutoff position, the inlet of the internal passage is shut off by entering the working pressure recess, and   wherein, in the case that the valve body exists at the communication position, the inlet of the internal passage is positioned outside the working pressure recess, so that the inlet is exposed to the interior of the portion of the suction pressure zone within the compressor.   
   
   
       5 . The refrigerant suction structure according to  claim 4 , wherein the guide cylinder is formed as an independent body from members of the compressor other than the valve body, so as to be allowed to move in a radial direction of the rotary shaft with respect to members of the compressor other than the valve body. 
   
   
       6 . The refrigerant suction structure according to  claim 2 , wherein the introduction passage has an inlet for accepting the refrigerant from the suction pressure zone, and the inlet of the introduction passage is positioned in an end surface of the rotary valve,
 wherein the outlets of the introduction passage are positioned in a peripheral surface of the rotary valve,   wherein the valve body is fitted into the introduction passage from the inlet of the introduction passage, and   wherein, in the case that the switch portion is in the shutoff state, the valve body is arranged in the introduction passage in such a manner as to shut off the outlets of the introduction passage from the portion of the suction pressure zone within the compressor.   
   
   
       7 . The refrigerant suction structure according to  claim 6 , wherein the introduction passage has an in-shaft passage positioned in the rotary shaft, and the in-shaft passage extends in a direction of a rotation axis of the rotary shaft,
 wherein the outlets of the introduction passage extend through a peripheral surface of the rotary shaft so as to communicate with the in-shaft passage,   wherein the valve body is fitted into the in-shaft passage in such a manner as to be slidable in a direction of the rotation axis within the introduction passage,   wherein the valve body is moved in the direction of the rotation axis within the in-shaft passage, so as to be switched between the communication position and the shutoff position, and   wherein the valve body at the shutoff position shuts off the outlets of the introduction passage with respect to the in-shaft passage.   
   
   
       8 . The refrigerant suction structure according to  claim 3 , wherein the switch portion has a flat valve seat surface, the valve body has a flat seal surface, and the seal surface comes into surface contact with the valve seat surface in a state in which the valve body exists at the shutoff position. 
   
   
       9 . The refrigerant suction structure according to  claim 1 , wherein the compressor has a discharge pressure zone,
 wherein the working pressure applying portion has an inflow passage reaching the working pressure chamber from the discharge pressure zone, and   wherein the refrigerant in the discharge pressure zone is introduced to the working pressure chamber via the inflow passage.   
   
   
       10 . The refrigerant suction structure according to  claim 9 , wherein an oil separator is provided on the inflow passage, and the oil separator separates oil from the refrigerant within the discharge pressure zone,
 wherein a constriction is provided in a portion of the inflow passage in a downstream side of the oil separator, and   wherein the portion of the inflow passage in the downstream side of the oil separator serves as an oil passage introducing the oil separated by the oil separator to the constriction.   
   
   
       11 . The refrigerant suction structure according to  claim 9 , wherein the discharge pressure zone has a portion within the compressor,
 wherein the portion of the discharge pressure zone within the compressor is connected to the portion of the suction pressure zone within the compressor via an external refrigerant circuit, and the external refrigerant circuit has a portion of the discharge pressure zone,   wherein the inflow passage is connected to the portion of the discharge pressure zone of the external refrigerant circuit,   wherein the working pressure applying portion is provided with an electromagnetic on-off valve for opening and closing the inflow passage, and a check valve, and   wherein the check valve is arranged in a portion of the external refrigerant circuit in a downstream side of a connection portion between the portion of the discharge pressure zone in the external refrigerant circuit and the inflow passage.   
   
   
       12 . The refrigerant suction structure according to  claim 1 , wherein the working pressure applying portion is provided with an electromagnetic three-way valve,
 wherein the working pressure chamber is connected to the electromagnetic three-way valve via a common passage,   wherein the electromagnetic three-way valve is connected to a discharge pressure zone via a feed passage,   wherein the electromagnetic three-way valve is connected to a suction pressure zone via a discharge passage, and   wherein the electromagnetic three-way valve is structured to be switched between a first state, in which the common passage communicates with the feed passage, and a second state, in which the common passage communicates with the discharge passage.   
   
   
       13 . The refrigerant suction structure according to  claim 1 , wherein the compressor comprises:
 a cylinder block having the cylinder bores; and   a rear housing member coupled to the cylinder block, and   wherein the rear housing member has in it a suction chamber, and the working pressure chamber is defined within the rear housing member.   
   
   
       14 . A refrigerant suction structure in a fixed displacement type piston compressor, wherein the compressor comprises:
 a rotary shaft coupled to an external drive source via a clutch;   a plurality of cylinder bores arranged around the rotary shaft;   a plurality of pistons defining compression chambers in the cylinder bores by being respectively accommodated in the cylinder bores;   a cam body integrated with the rotary shaft, the cam body converting a rotation of the rotary shaft into reciprocation of each of the pistons;   a suction pressure zone; and   a rotary valve having an introduction passage for introducing a refrigerant from the suction pressure zone to each of the compression chambers, the rotary valve integrally rotating with the rotary shaft, the suction pressure zone having a portion within the compressor, and the introduction passage having outlets for feeding out the refrigerant toward each of the compression chambers,   wherein the refrigerant suction structure has a switch portion capable of being switched between a communication state and a shutoff state,   wherein the switch portion in the communication state allows the portion of the suction pressure zone within the compressor to communicate with the outlets of the introduction passage,   wherein the switch portion in the shutoff state shuts off the portion of the suction pressure zone within the compressor from the outlets of the introduction passage,   wherein the switch portion includes:   a valve body capable of being switched between a communication position and a shutoff position, the valve body in the communication position allowing the portion of the suction pressure zone within the compressor to communicate with the outlets of the introduction passage, and the valve body in the shutoff position shutting off the portion of the suction pressure zone within the compressor from the outlets of the introduction passage; and   an electromagnetic driving portion driving the valve body on the basis of an electromagnetic force.   
   
   
       15 . The refrigerant suction structure according to  claim 14 , wherein the switch portion is provided with a second return spring returning the valve body to the communication position, and
 wherein the electromagnetic driving portion drives the valve body from the communication position toward the shutoff position.   
   
   
       16 . The refrigerant suction structure according to  claim 15 , wherein the switch portion has a pressure recess, and the valve body is slidably accommodated within the pressure recess, whereby the valve body defines a pressure chamber within the pressure recess,
 wherein the pressure chamber communicates with the portion of the suction pressure zone within the compressor,   wherein the pressure in the portion of the suction pressure zone within the compressor acts against the pressure in the pressure chamber via the valve body,   wherein the second return spring is accommodated in the pressure chamber, and the second return spring urges the valve body in a direction in which the valve body pops out from the interior of the pressure recess, and   wherein the electromagnetic driving portion drives the valve body in such a manner as to push the valve body into the pressure recess.   
   
   
       17 . The refrigerant suction structure according to  claim 14 , wherein the switch portion has a pressure recess, and the valve body is slidably accommodated within the pressure recess, whereby the valve body defines a pressure chamber within the pressure recess,
 wherein the pressure chamber communicates with the portion of the suction pressure zone within the compressor,   wherein the pressure in the portion of the suction pressure zone within the compressor acts against the pressure in the pressure chamber via the valve body,   wherein the switch portion is provided with a retaining spring which acts to retain the valve body at the shutoff position by pressing the valve body into the pressure recess, and   wherein the electromagnetic driving portion drives the valve body from the communication position toward the shutoff position.   
   
   
       18 . The refrigerant suction structure according to  claim 17 , wherein the introduction passage has an inlet for accepting the refrigerant from the suction pressure zone, and
 wherein, in the case that the switch portion is in the shutoff state, the valve body is arranged in such a manner as to shut off the inlet of the introduction passage from the portion of the suction pressure zone within the compressor.   
   
   
       19 . The refrigerant suction structure according to  claim 18 , wherein the switch portion has a flat valve seat surface, the valve body has a flat seal surface, and the seal surface comes into surface contact with the valve seat surface in a state in which the valve body exists at the shutoff position. 
   
   
       20 . The refrigerant suction structure according to  claim 17 , wherein the introduction passage has an inlet for accepting the refrigerant from the suction pressure zone, and the inlet of the introduction passage is positioned in an end surface of the rotary valve,
 wherein the outlets of the introduction passage are positioned in a peripheral surface of the rotary valve,   wherein a rotation axis of the rotary valve intersects the end surface,   wherein the refrigerant suction structure comprises:   a valve accommodation chamber rotatably accommodating the rotary valve; and   a guide cylinder surrounding the rotation axis outside the valve accommodation chamber,   wherein a cylinder interior of the guide cylinder communicates with an inlet of the introduction passage,   wherein the valve body is slidably fitted to the guide cylinder, the valve body has an internal passage communicating with the cylinder interior of the guide cylinder, and the internal passage has an inlet for accepting the refrigerant from the suction pressure zone,   wherein, in the case that the valve body exists at the shutoff position, the inlet of the internal passage is shut off by entering the pressure recess, and   wherein, in the case that the valve body exists at the communication position, the inlet of the internal passage is positioned outside of the pressure recess, so that the inlet is exposed to the portion of the suction pressure zone within the compressor.   
   
   
       21 . The refrigerant suction structure according to  claim 20 , wherein the guide cylinder is formed as an independent body from members of the compressor other than the valve body, so as to be allowed to move in a radial direction of the rotary shaft with respect to the members of the compressor other than the valve body. 
   
   
       22 . The refrigerant suction structure according to  claim 14 , wherein the introduction passage has an inlet for accepting the refrigerant from the suction pressure zone, and the inlet of the introduction passage is positioned in an end surface of the rotary valve,
 wherein the outlets of the introduction passage are positioned in a peripheral surface of the rotary valve,   wherein the valve body is fitted into the introduction passage from the inlet of the introduction passage, and   wherein, in the case that the switch portion is in the shutoff state, the valve body is arranged in the introduction passage in such a manner as to shut off the outlets of the introduction passage from the portion of the suction pressure zone within the compressor.   
   
   
       23 . The refrigerant suction structure according to  claim 22 , wherein the introduction passage has an in-shaft passage positioned in the rotary shaft, and the in-shaft passage extends in a direction of a rotation axis of the rotary shaft,
 wherein the outlets of the introduction passage extends through a peripheral surface of the rotary shaft so as to communicate with the in-shaft passage,   wherein the valve body is fitted into the in-shaft passage in such a manner as to be slidable in a direction of the rotation axis within the introduction passage,   wherein the valve body is moved in the direction of the rotation axis within the in-shaft passage, so as to be switched between the communication position and the shutoff position, and   wherein the valve body at the shutoff position shuts off the outlets of the introduction passage with respect to the in-shaft passage.   
   
   
       24 . The refrigerant suction structure according to  claim 14 , wherein the compressor comprises:
 a cylinder block having the cylinder bores; and   a rear housing member coupled to the cylinder block, and   wherein the rear housing member has in it a suction chamber, and the valve body is arranged within the rear housing member.   
   
   
       25 . An operation control method in a fixed displacement type piston compressor, wherein the compressor comprises:
 a rotary shaft coupled to an external drive source via a clutch;   a plurality of cylinder bores arranged around the rotary shaft;   a plurality of pistons defining compression chambers in the cylinder bores by being respectively accommodated in the cylinder bores;   a cam body integrated with the rotary shaft, the cam body converting a rotation of the rotary shaft into reciprocation of each of the pistons;   a suction pressure zone;   a rotary valve having an introduction passage for introducing a refrigerant from the suction pressure zone to each of the compression chambers; and   a discharge pressure zone,   wherein the rotary valves integrally rotate with the rotary shaft,   wherein the suction pressure zone has a portion within the compressor,   wherein the introduction passage has outlets for feeding out the refrigerant toward each of the compressors,   wherein the operation control method comprises:   preparing a switch portion capable of being switched between a communication state and a shutoff state, wherein the switch portion in the communication state allows the portion of the suction pressure zone within the compressor to communicate with the outlets of the introduction passage, the switch portion in the shutoff state shuts off the portion of the suction pressure zone within the compressor from the outlets of the introduction passage, the switch portion is provided with a valve body, a working pressure chamber, and a working pressure applying portion, wherein the valve body is capable being switched between a communication position allowing the portion of the suction pressure zone within the compressor to communicate with the outlet of the introduction passage, and a shutoff position shutting off the portion of the suction pressure zone within the compressor from the outlets of the introduction passage, wherein the working pressure chamber introduces a working pressure applied to the valve body to arrange the valve body at the communication position, wherein the working pressure applying portion applies the working pressure to the working pressure chamber, and wherein the working pressure applying portion is provided with a switch valve that is switched between a first state, in which the refrigerant in the discharge pressure zone can be fed to the working pressure chamber and a second state, in which the refrigerant in the discharge pressure chamber cannot be fed to the working pressure chamber;   setting the clutch to a coupled state after setting the switch valve to the second state, at a time of switching the clutch from the shutoff state to the coupled state; and   switching the switch valve to the first state after setting the clutch to the coupled state.   
   
   
       26 . The operation control method according to  claim 25 , wherein the clutch is an electromagnetic clutch which, when magnetized, comes to the coupled state coupling the rotary shaft to the external driving source, and
 wherein the operation control method comprises:   gradually increasing an electric current fed to the electromagnetic clutch to magnetize the electromagnetic clutch, at a time of switching the electromagnetic clutch from a demagnetized state to a magnetized state; and   switching the switch valve from the second state to the first state after a value of the electric current becomes maximum.   
   
   
       27 . An operation control method in a fixed displacement type piston compressor, wherein the compressor comprises:
 a rotary shaft coupled to an external drive source via a clutch;   a plurality of cylinder bores arranged around the rotary shaft;   a plurality of pistons defining compression chambers in the cylinder bores by being respectively accommodated in the cylinder bores;   a cam body integrated with the rotary shaft, the cam body converting a rotation of the rotary shaft into reciprocation of each of the pistons;   a suction pressure zone;   a rotary valve having an introduction passage for introducing a refrigerant from the suction pressure zone to each of the compression chambers, the rotary valve integrally rotating with the rotary shaft, the suction pressure zone having a portion within the compressor, and the introduction passage having outlets for feeding out the refrigerant toward each of the compression chambers,   wherein the operation control method comprises:   preparing a switch portion capable of being switched between a communication state and a shutoff state, wherein the switch portion in the communication state allows the portion of the suction pressure zone within the compressor to communicate with the outlets of the introduction passage, the switch portion in the shutoff state shuts off the portion of the suction pressure zone within the compressor from the outlets of the introduction passage, the switch portion is provided with a valve body and an electromagnetic driving portion, wherein the valve body is capable being switched between a communication position allowing the portion of the suction pressure zone within the compressor to communicate with the outlets of the introduction passage, and a shutoff position shutting off the portion of the suction pressure zone within the compressor from the outlets of the introduction passage, wherein the electromagnetic driving portion is capable of driving the valve body on the basis of an electromagnetic force, and the electromagnetic driving portion is capable of switching the valve body between a first state, in which the valve body is arranged at the communication position, and a second state, in which the valve body is arranged at the shutoff position;   wherein the operation control method comprises:   setting the clutch to the coupled state after setting the electromagnetic driving portion to the second state, at a time of switching the clutch from the shutoff state to the coupled state; and   setting the electromagnetic driving portion to the first state after setting the clutch to the coupled state.   
   
   
       28 . The operation control method according to  claim 27 , wherein the clutch is an electromagnetic clutch which, when magnetized, comes to the coupled state coupling the rotary shaft to the external driving source, and
 wherein the operation control method comprises:   gradually increasing an electric current fed to the electromagnetic clutch to magnetize the electromagnetic clutch, at a time of switching the electromagnetic clutch from a demagnetized state to a magnetized state; and   demagnetizing the electromagnetic driving portion after a value of the electric current becomes maximum.