JP2019065754A - Variable displacement compressor - Google Patents

Abstract

To provide a variable displacement compressor for enabling power saving operation by itself without using a signal for displacement control from external control equipment.SOLUTION: The variable displacement compressor includes a displacement control valve 70 having a ball valve 700 for controlling a compression displacement with the ball valve 700 opening/closing a communication path 785 so that the suction pressure of a suction chamber 14 becomes a first pressure, a solenoid valve coil 750 for driving the ball valve 700, a discharge pressure sensor 80, and a solenoid valve driving circuit 82 for, when the discharge pressure of a discharge chamber 15 is determined to fall within a predetermined range on the basis of a signal output from the discharge pressure sensor 80, controlling the solenoid valve coil 750 so that the suction pressure of the suction chamber 14 becomes a second pressure higher than the first pressure.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a variable displacement compressor having a variable compression capacity.

  Conventionally, there is an internally variable variable displacement compressor described in Patent Document 1. The compressor has a crank chamber divided into a housing, a cylinder chamber communicating with the crank chamber, a swash plate disposed in the crank chamber, and a piston disposed in the cylinder chamber. In this compressor, the stroke angle of the piston changes and the compression capacity changes by automatically automatically adjusting the inclination angle of the swash plate in accordance with the differential pressure between the pressure in the crank chamber and the suction pressure of the compressor. It is a structure.

  In addition, this compressor has a valve body provided in a communication passage communicating the suction port of the compressor with the crank chamber, and the valve body opens and closes the communication passage so that the suction pressure becomes constant. Control the compressor to the appropriate capacity.

  Further, as such a variable displacement compressor, there is also an externally variable variable displacement compressor described in Patent Document 2. The compressor has a solenoid valve that changes the discharge capacity in accordance with a signal from an external control device such as an air conditioner ECU.

  When the compressor switches from the normal mode to the economy mode, the solenoid valve is controlled such that the suction pressure becomes higher in response to a signal for volume control from the air conditioner ECU. As a result, the discharge capacity can be further reduced, and power saving can be achieved.

  In this compressor, for example, when the outside air temperature is high, the compressor operates in the normal mode with a large discharge capacity, and when the outside air temperature is not very high, power saving is performed by switching the mode to operate in the economy mode with a small discharge capacity. Can be

JP-A-8-177735 JP, 2009-56840, A

  The internally variable variable displacement compressor described in Patent Document 1 does not have a solenoid valve that operates in response to a signal from an external control device, and control by an external control device such as an air conditioner ECU is unnecessary. It has become. For this reason, since the configuration is simple and low cost can be realized, it is suitable for a low cost vehicle.

  On the other hand, the externally variable variable displacement compressor described in Patent Document 2 can operate not only in the economy mode, but also can be controlled by an external control device such as an air conditioner ECU.

  For example, the external variable type variable displacement compressor detects various sensors such as an external air temperature sensor that detects an outside air temperature, and a temperature sensor that detects a temperature of an evaporator used for a vehicle air conditioning system. The value can be used to finely control the solenoid valve. Therefore, it is possible to perform high-performance air conditioning control, which is suitable for high-priced vehicles.

  In the compressor described in Patent Document 1, the valve body opens and closes the communication passage so as to make the suction pressure constant, and in the economy mode like the compressor described in Patent Document 2 Since it can not respond, it is difficult to save labor.

  Therefore, in a vehicle equipped with an internally variable variable displacement compressor, in order to save power in the economy mode, the mounted compressor is changed to an externally variable variable displacement compressor. It is also necessary to change the software of the external control device such as the air conditioner ECU and the wiring with the external control device, and further to add various sensors. Therefore, there is a problem that the cost is increased. Furthermore, there is also a problem that a significant increase in the number of development steps occurs as the compressor is changed.

  The present invention has been made in view of the above problems, and has an object of enabling power saving operation independently without using a signal from an external control device for capacity control.

  In order to achieve the above object, the invention according to claim 1 is a variable displacement compressor having a variable compression volume, which comprises a suction chamber (14) for sucking fluid, a crank chamber (110) for compressing fluid, and compression. A compressor housing (10) having a discharge chamber (15) for discharging the fluid, and a valve body (700 for opening and closing a communication passage (785) connecting the discharge chamber and the crank chamber according to the suction pressure of the suction chamber And the volume control valve (70) which controls the compression volume by opening and closing the communication passage so that the suction pressure of the suction chamber becomes the first pressure, and the discharge pressure of the discharge chamber. A discharge pressure detection unit (80, 83) for outputting a signal, and a control unit (82). The displacement control valve has a valve drive unit (750) for driving the valve body, and the control unit The discharge pressure of the discharge chamber is determined based on the signal output from the discharge pressure detection unit. If it is determined to be within the constant range, and controls the valve driving unit so that the suction pressure in the suction chamber is a second pressure higher than the first pressure.

  According to such a configuration, when the control unit determines that the discharge pressure of the discharge chamber is within the predetermined range based on the signal output from the discharge pressure detection unit, the suction pressure of the suction chamber is the first. Since the valve drive unit is controlled to have the second pressure higher than the pressure, power saving operation can be performed independently without using a signal from the external control device for capacity control.

  In addition, the code | symbol in the parenthesis of each means described by this column and the claim shows correspondence with the specific means as described in embodiment mentioned later.

It is a block diagram of a refrigerating cycle using a capacity variable compressor of a 1st embodiment. 1 is a schematic cross-sectional view of a variable displacement compressor according to a first embodiment. It is a figure showing the whole composition of a control system of a capacity variable compressor of a 1st embodiment. It is a figure showing the relationship between the suction pressure and discharge pressure in a capacity variable compressor of a 1st embodiment. It is a flowchart of a compressor control part. It is a figure showing the movement of the displacement control valve when the solenoid valve coil is in the non-energized state. It is a figure showing the movement of the displacement control valve when the solenoid valve coil is in the non-energized state. It is a figure showing movement of a capacity control valve when a solenoid valve coil is in a state of energization. It is a figure showing the whole composition of a control system of a capacity variable compressor of a 2nd embodiment.

  Hereinafter, an embodiment of the present invention will be described based on the drawings. In the following embodiments, parts identical or equivalent to each other are denoted by the same reference numerals in the drawings.

First Embodiment
The variable displacement compressor according to the first embodiment will be described with reference to FIGS. 1 to 8. As shown in FIG. 1, the variable-capacity compressor 1 is disposed in a refrigeration cycle circulation line including a condenser 20, an expansion valve 21, an evaporator 23, and the like.

  As shown in FIG. 2, the present variable displacement compressor 1 has a swash plate 60 whose tilt angle changes according to the pressure balance of fluid inside the compressor housing 10, and the tilt angle of the swash plate 60 changes. It is configured as an internal variable type variable displacement compressor in which the discharge displacement is changed by this. This variable displacement compressor is used for a vehicle air conditioner or the like.

  The variable displacement compressor 1 includes a compressor housing 10, a piston 30, a piston rod 31, a shaft 40, an electromagnetic clutch 50, a swash plate 60 and a displacement control valve 70. The compressor housing 10 accommodates a piston 30, a piston rod 31, a shaft 40, a swash plate 60 and a solenoid valve coil 750.

  Inside the compressor housing 10, a crank chamber 110 and a plurality of cylinder chambers 120 communicating with the crank chamber 110 are formed. A piston 30 is slidably fitted in each of the cylinder chambers 120 in the axial direction, and one end of a piston rod 31 is connected to the side of the crank chamber 110 of each piston 30.

  The compressor housing 10 rotatably supports a shaft 40. The shaft 40 is drivingly connected to an engine (not shown) by a driving belt (not shown) which is wound around a pulley 52 of the electromagnetic clutch 50, and is rotationally driven by the engine. The shaft 40 is connected so as to be changeable in mounting angle in the crank chamber 110 by a known connecting mechanism of the swash plate 60.

  The piston rod 31 is formed with a shoe receiving portion 32 for housing the spherical shoe 61. The shoe 61 functions as a conversion mechanism that converts the rotation of the swash plate 60 into the reciprocating motion of each piston 30. Each piston 30 is connected to the swash plate 60 via the piston rod 31 and the shoes 61, so that the inside of the cylinder chamber 120 can be reciprocated with a stroke corresponding to the inclination angle of the swash plate 60.

  When the swash plate 60 is rotated and driven by the shaft 40 in an inclined state, the pistons 30 of each cylinder chamber 120 reciprocate with a stroke corresponding to the inclination angle of the swash plate 60, and the inclination angle corresponds to the crank chamber pressure Pc. It is automatically adjusted according to the differential pressure with the suction pressure (compressor suction pressure) Ps of each cylinder chamber 120.

  Specifically, in the variable displacement compressor 1, when the crank chamber pressure Pc is increased, the inclination angle of the swash plate 60 is reduced, the stroke of the piston 30 is reduced, and the discharge capacity is thereby reduced. In the variable displacement compressor 1, when the crank chamber pressure Pc is decreased, the inclination angle of the swash plate 60 is increased, the stroke of the piston 30 is increased, and the discharge capacity is thereby increased. In addition, the variable displacement compressor 1 enters a full load operation state when the crank chamber pressure Pc becomes a pressure substantially equal to the suction pressure Ps.

  The crank chamber pressure Pc is determined by the flow rate of fluid leaking between the cylinder chamber 120 and the piston 30. In each cylinder chamber 120, a suction chamber 14 having a suction valve 12 and a discharge chamber 15 having a discharge valve 13 are formed. Each of the suction valve 12 and the discharge valve 13 is a one-way valve.

  The suction chamber 14 of each cylinder chamber 120 communicates with the suction port 17 via the suction passage 16, and the discharge chamber 15 communicates with the discharge port 19 via the discharge passage 18.

  The variable displacement compressor 1 of the present embodiment has a discharge pressure sensor 80 that detects the discharge pressure of the fluid discharged from the discharge port 19. The discharge pressure sensor 80 outputs a signal corresponding to the discharge pressure of the fluid discharged from the discharge port 19 to a compressor control unit 81 described later.

  In the compressor housing 10, a valve receiving hole A for fixing the displacement control valve 70 is formed. The valve housing 71 of the displacement control valve 70 is inserted into and attached to the valve receiving hole A.

  The volume control valve 70 includes a valve housing 71, a ball valve 700, a first rod 710, a bellows 720, a first coil spring 730, a spring seat 740, a second rod 745, a solenoid valve coil 750, a movable body 760, and a second coil spring. 770, has.

  In the valve housing 71, a discharge pressure chamber 780, a crank pressure chamber 781, a suction pressure chamber 782, and a coil storage chamber 783 are formed. The displacement control valve 70 opens and closes a communication passage 785 that communicates between the discharge pressure chamber 780 and the crank pressure chamber 781.

  The discharge pressure chamber 780 is connected to the discharge chamber 15 of the compressor housing 10 via the discharge pressure passage 112. The crank pressure chamber 781 is connected to the crank chamber 110 of the compressor housing 10 via the passage 113 and to the discharge pressure chamber 780 via the communication passage 785. The suction pressure chamber 782 is connected to the suction chamber 14 of the compressor housing 10 via the suction pressure passage 111.

  Further, the discharge pressure chamber 780 and the crank pressure chamber 781 communicate with each other, and a rod-shaped first rod 710 is disposed in the communicating portion. Further, a second rod 745 is disposed in the coil storage chamber 783. The first rod 710 and the second rod 745 are connected via a bellows bellows 720 disposed to cover the first coil spring 730.

  A ball valve 700 is provided at one end of the first rod 710. The ball valve 700 functions as a ball valve that adjusts the opening degree of the communication passage 785. The ball valve 700 is disposed in the discharge pressure chamber 780 so as to close a communication passage 785 communicating the discharge pressure chamber 780 with the crank pressure chamber 781.

  When the ball valve 700 is separated from the communication passage 785 in accordance with the axial movement of the first rod 710, the communication passage 785 is opened, and the ball valve 700 is in communication with the axial movement of the first rod 710. When it abuts on 785, the communication passage 785 is closed.

  The bellows 720 has a bellows shape. The bellows 720 is closed at one end on the first rod 710 side, and the other end of the first rod 710 is connected to one end on the first rod 710 side. The other end of the bellows 720 is bonded to the surface of the suction pressure chamber 782 on the coil storage chamber 783 side.

  The bellows 720 expands and contracts in the axial direction of the first rod 710 according to the pressure of the suction pressure chamber 782. The suction pressure chamber 782 expands as the pressure in the suction pressure chamber 782 decreases, and the axial length of the rod 710 shortens, and as the pressure in the suction pressure chamber 782 increases, the suction pressure chamber 782 contracts and the axial direction of the rod 710 decreases. Length will be longer.

  Inside the bellows 720, a first coil spring 730 is disposed. One end of the first coil spring 730 is connected to the inner surface on one end side of the bellows 720 on the ball valve 700 side, and the other end of the first coil spring 730 is connected to one surface of the disk-shaped spring seat 740.

  The inside of the bellows 720 of this embodiment is vacuum, and the inside is kept airtight.

  The first coil spring 730 biases one end and the other end of the bellows 720 away from each other so that the bellows 720 extends in the axial direction.

  The spring seat 740 is disposed in the communication passage between the suction pressure chamber 782 and the coil storage chamber 783. The gap between the spring seat 740 and the communication passage between the suction pressure chamber 782 and the coil storage chamber 783 is sealed.

  The spring seat 740 is connected to one end of the second rod 745, and the movable body 760 is connected to the other end of the second rod 745. The movable body 760 is configured as a movable iron piece, and is disposed inside the annular solenoid valve coil 750.

  In the coil storage chamber 783, a second coil spring 770 for generating a suction force for suctioning the second rod 745 together with the movable body 760, and urging the second rod 745 together with the movable body 760 toward the first rod 710 by electromagnetic force. A solenoid valve coil 750 is disposed.

  Next, the operation of the displacement control valve 70 will be described.

  When the solenoid valve coil 750 is in the non-energized state, the ball valve 700 fixed to the first rod 710 is attracted toward the second coil spring 770 by the suction force of the second coil spring 770. Therefore, the ball valve 700 abuts on the communication passage 785, and the opening degree of the communication passage 785 decreases. Thus, the inflow of fluid from discharge pressure chamber 780 to crank pressure chamber 781 is restricted.

  Here, when the suction pressure Ps of the fluid in the suction pressure chamber 782 decreases, as shown in FIG. 7, the bellows 720 extends in the axial direction of the first rod 710, so the first rod 710 connected to the bellows 720 discharges. Move to the pressure chamber 780 side. Thereby, the ball valve 700 is separated from the communication passage 785, and the opening degree of the communication passage 785 becomes large.

  Also, when the solenoid valve coil 750 is energized, the movable body 760 moves to the bellows 720 side against the suction force of the second coil spring 770, and the second rod 745, the first coil spring 730 and the second rod 745 Moves to the discharge pressure chamber 780 side. Thereby, the ball valve 700 is separated from the communication passage 785, and the opening degree of the communication passage 785 becomes large.

  As described above, the displacement control valve 70 opens and closes the communication passage 785 that provides communication between the discharge pressure chamber 780 and the crank pressure chamber 781 according to the suction pressure Ps of the fluid in the suction pressure chamber 782. Is configured to preferentially increase the degree of opening of the communication passage 785 when the switch is in the energized state.

  FIG. 3 is a diagram showing an entire configuration of a control system of the variable displacement compressor 1 according to the present embodiment. The variable displacement compressor 1 includes a discharge pressure sensor 80, a compressor control unit 81, an electromagnetic valve drive circuit 82, an electromagnetic clutch 50, and an electromagnetic clutch coil 51.

  The compressor control unit 81 is configured as a computer including a CPU, a memory, an I / O, and the like, and the CPU performs various processes in accordance with a program stored in the memory. The compressor control unit 81 has a solenoid valve drive circuit 82.

  The solenoid valve drive circuit 82 is a drive circuit that drives the solenoid valve coil 750. The solenoid valve drive circuit 82 has a plurality of transistors, generates a PWM (Pulse Width Modulation) signal according to a signal input from the compressor control unit 81, and generates a solenoid valve coil 750 with a current according to the PWM signal. Supply to

  When a current corresponding to the PWM signal flows through the solenoid valve coil 750, the movable body 760 disposed inside the annular solenoid valve coil 750 is pulled by the electromagnetic force, and the ball valve 700 connected to the movable body 760 The passage 785 is opened.

  The air conditioner ECU 90 adjusts the ratio between the volume of air flowing around the heater core of the vehicle and the volume of cold air cooled by the evaporator 23 based on signals input from various sensors such as an outside air temperature sensor (not shown). Control the air mix door etc.

  The electromagnetic clutch 50 controls the power transmission between the pulley 52 and the shaft 40 using an electromagnetic force generated by energizing the electromagnetic clutch coil 51.

  The electric circuit such as the compressor control unit 81 of the variable displacement compressor 1 and the electromagnetic clutch coil 51 are connected from the battery 91 through the relay 92, respectively. That is, the electric circuit such as the compressor control unit 81 of the variable displacement compressor 1 and the electromagnetic clutch coil 51 are connected in parallel. The relay 92 is controlled by a control signal from the air conditioner ECU 90.

  Next, the relationship between the discharge pressure and the suction pressure in the present variable displacement compressor 1 will be described with reference to FIG. FIG. 4 shows the relationship between the suction pressure and the discharge pressure in the variable displacement compressor 1. The ordinate represents the suction pressure, and the abscissa represents the discharge pressure. The discharge pressure has a relationship of becoming higher as the outside air temperature becomes higher.

  In summer when the outside air temperature is high, the discharge pressure also becomes high. In this case, it is necessary to blow a large amount of cold air into the vehicle cabin in order to ensure cool-down performance. That is, in order to secure the cool-down property in the summer when the outside air temperature is high, it is necessary to lower the suction pressure in the region where the discharge pressure is high.

  In addition, the discharge pressure also decreases in winter when the outside air temperature is low. In this case, it is necessary to blow cool air into the vehicle cabin in order to prevent the windows from being fogged. That is, in order to ensure the antifogging property in the winter when the outside air temperature is low, it is necessary to lower the suction pressure in the region where the discharge pressure is low. Also, in winter when the outside air temperature is low, the suction pressure can not be made very low to prevent frost. That is, since the ice adheres to the surface of the evaporator 23 if the suction pressure is set too low in the region where the discharge pressure is low, the suction pressure is set low to an extent that frost does not occur in the region where the discharge pressure is low. There is a need.

  However, in the spring and autumn when the outside temperature is not so high, it is not necessary to release air that is as cold as summer and winter. Therefore, in the variable displacement compressor 1, the solenoid valve coil 750 is energized in the middle region between the region where the outside air temperature is high and the region where the outside air temperature is low, and the discharge pressure is compared with the regions where the outside air temperature is high and low. Implement power saving operation to make In the middle region between the region where the outside air temperature is high and the region where the outside air temperature is low, it is preferable to set the suction pressure high as long as comfort can be ensured.

  The variable displacement compressor 1 according to the present embodiment is not controlled so that the suction pressure is constant as in the conventional internally variable variable displacement compressor, but the compressor control unit 81 controls the discharge pressure sensor 80. When the discharge pressure detected by the above becomes an intermediate region, the solenoid valve coil 750 of the volume control valve 70 is controlled so that the suction pressure becomes higher. As described above, by controlling the suction pressure to be a higher pressure, power saving operation with a small discharge capacity is realized.

  Next, this control will be described according to the flowchart of FIG. When energization from the battery 91 is started, the compressor control unit 81 periodically performs the process shown in FIG. 5.

  First, at S100, the compressor control unit 81 specifies the discharge pressure Pd. The discharge pressure Pd can be specified based on the signal output from the discharge pressure sensor 80.

  Next, in S102, the compressor control unit 81 determines whether the discharge pressure Pd is within the set range. Specifically, it is determined whether the discharge pressure Pd is equal to or higher than the first threshold Pd1 shown in FIG. 4 and lower than the second threshold Pd2. That is, it is determined whether the discharge pressure is in the middle region.

  Here, when the discharge pressure Pd is less than the first threshold value Pd1 or greater than or equal to the second threshold value Pd2, the compressor control unit 81 stops the energization of the solenoid valve coil 750 in S106.

  When the solenoid valve coil 750 is not energized and the suction pressure Ps of the fluid in the suction pressure chamber 782 is equal to or higher than the predetermined pressure, the bellows 720 contracts in the axial direction of the first rod 710 as shown in FIG. The ball valve 700 fixed to the first rod 710 is attracted to the second coil spring 770 side. Therefore, the ball valve 700 is positioned to close the communication passage 785, and the opening degree of the communication passage 785 is reduced. Therefore, the inflow of fluid from discharge pressure chamber 780 to crank pressure chamber 781 is restricted, and suction pressure Ps decreases.

  Further, when the suction pressure Ps of the fluid in the suction pressure chamber 782 decreases from the predetermined pressure while the solenoid valve coil 750 is not energized, the bellows 720 extends in the axial direction of the first rod 710, as shown in FIG. The first rod 710 connected to the bellows 720 moves to the discharge pressure chamber 780 side. Thereby, the ball valve 700 is separated from the communication passage 785, and the opening degree of the communication passage 785 becomes large. As a result, the inflow of fluid from the discharge pressure chamber 780 to the crank pressure chamber 781 increases, and the suction pressure Ps rises.

  As described above, when the solenoid valve coil 750 is not energized, the ball valve 700 adjusts the opening degree of the communication passage 785 in order to make the suction pressure Ps constant.

  Further, when the discharge pressure Pd is equal to or higher than the first threshold value Pd1 and smaller than the second threshold value Pd2, the compressor control unit 81 carries out energization of the electromagnetic valve coil 750 in S104.

  In this case, as shown in FIG. 8, the solenoid valve coil 750 is in an energized state, the movable body 760 moves to the bellows 720 side against the suction force of the second coil spring 770, and the second rod 745, the first The coil spring 730 and the second rod 745 move to the discharge pressure chamber 780 side. Thereby, the ball valve 700 is separated from the communication passage 785, and the opening degree of the communication passage 785 becomes large. Accordingly, the inflow of fluid from the discharge pressure chamber 780 to the crank pressure chamber 781 is increased. Further, the suction pressure Ps becomes a second pressure Ps2 higher than the first pressure Ps1. As described above, by controlling the suction pressure to be the second pressure Ps2 higher than the first pressure Ps1, a power saving operation with a small displacement is realized.

  As described above, the variable displacement compressor 1 includes the compressor housing 10 having the suction chamber 14 for sucking the fluid, the crank chamber 110 for compressing the fluid, and the discharge chamber 15 for discharging the compressed fluid. There is. Further, the variable displacement compressor 1 has a ball valve 700 for opening and closing a communication passage 785 for communicating the discharge chamber 15 with the crank chamber 110 according to the suction pressure of the suction chamber 14. The volume control valve 70 controls the compression volume by opening and closing the communication passage 785 so that the suction pressure of the air pressure becomes the first pressure. Furthermore, the variable displacement compressor 1 includes a discharge pressure sensor 80 that outputs a signal corresponding to the discharge pressure of the discharge chamber 15, and a solenoid valve drive circuit 82. Further, the displacement control valve has a valve drive unit 750 that drives the ball valve 700, and the solenoid valve drive circuit 82 has the discharge pressure of the discharge chamber within a predetermined range based on the signal output from the discharge pressure sensor 80. If it is determined that the pressure in the suction chamber 14 is determined, the valve drive unit 750 is controlled so that the suction pressure in the suction chamber 14 becomes a second pressure higher than the first pressure.

  According to such a configuration, when the solenoid valve drive circuit 82 determines that the discharge pressure of the discharge chamber 15 is within the predetermined range based on the signal output from the discharge pressure sensor 80, the suction of the suction chamber 14 is performed. Since the valve drive unit 750 is controlled so that the pressure becomes the second pressure higher than the first pressure, power saving operation can be performed independently without using a signal for controlling the displacement from the external control device. it can.

  Further, the valve drive unit 750 includes a movable body 760 connected to the ball valve 700, and an electromagnetic valve coil 750 for driving the movable body 760 by an electromagnetic force. When the solenoid valve drive circuit 82 determines that the discharge pressure of the discharge chamber 15 detected by the discharge pressure sensor 80 is within the predetermined range, the solenoid valve coil is opened so that the ball valve 700 opens the communication passage 785. Control 750.

  Thus, when the solenoid valve drive circuit 82 determines that the discharge pressure of the discharge chamber 15 detected by the discharge pressure sensor 80 is within the predetermined range, the ball valve 700 opens the communication passage 785 so as to open the communication passage 785. The valve coil 750 can be controlled.

  Further, the solenoid valve drive circuit 82 is configured such that the discharge pressure of the fluid detected by the discharge pressure sensor 80 is equal to or greater than a first threshold Pd1, and the discharge pressure of the fluid detected by the discharge pressure sensor 80 is greater than the first threshold. If the second threshold Pd2 is less than the second threshold Pd2, the solenoid valve coil 750 is controlled so that the suction pressure becomes a second pressure higher than the first pressure.

  Thus, in the solenoid valve drive circuit 82, the discharge pressure of the fluid detected by the discharge pressure sensor 80 is equal to or higher than the first threshold Pd1, and the discharge pressure of the fluid detected by the discharge pressure sensor 80 is higher than the first threshold. When it becomes less than the large second threshold value Pd2, power saving operation can be realized by controlling the solenoid valve coil 750 so that the suction pressure becomes the second pressure higher than the first pressure.

  Also, the solenoid valve drive circuit 82 is configured such that the discharge pressure of the fluid detected by the discharge pressure sensor 80 is less than the first threshold Pd1, or the discharge pressure of the fluid detected by the discharge pressure sensor 80 is greater than the first threshold. When the threshold value Pd2 or more is reached, the solenoid valve coil 750 is controlled so that the ball valve 700 opens the communication passage 785 according to the suction pressure of the suction chamber 14 so that the suction pressure of the suction chamber 14 becomes the first pressure. Open and close.

  Thus, in the solenoid valve drive circuit 82, the discharge pressure of the fluid detected by the discharge pressure sensor 80 is less than the first threshold Pd1, or the discharge pressure of the fluid detected by the discharge pressure sensor 80 is higher than the first threshold When the large second threshold Pd2 is reached, the solenoid valve coil 750 is controlled so that the ball valve 700 opens and closes the communication passage 785 according to the suction pressure of the suction chamber 14 to make the suction pressure of the suction chamber 14 The compression volume can be controlled to a pressure of 1.

  The volume control valve 70 has one end fixed to the ball valve 700 and the other end connected to the first rod 710 connected to one end of the bellows 720 which expands and contracts according to suction pressure, and one end connected to the movable body 760 The second rod 745 is connected to the other end of the bellows 720, and the spring member 770 suctions the second rod 745 to the opposite side of the bellows 720 side. Then, the movable body 760 is moved toward the bellows 720 against the suction force of the spring member 770 by the electromagnetic force generated by the electromagnetic valve coil 750, and the ball valve 700 opens the communication passage 785.

  Thus, the ball valve 700 opens the communication passage 785 by moving the movable body 760 toward the bellows 720 against the suction force of the spring member 770 by the electromagnetic force generated by the electromagnetic valve coil 750. Can.

Second Embodiment
A variable displacement compressor according to a second embodiment will be described with reference to FIG. The variable displacement compressor according to the first embodiment has the discharge pressure sensor 80, and the compressor control unit 81 sets the discharge pressure of the discharge chamber within a predetermined range based on the discharge pressure detected by the discharge pressure sensor 80. It is determined whether there is any. On the other hand, the variable displacement compressor of the present embodiment has a pressure switch 83 instead of the discharge pressure sensor 80, and the compressor control unit 81 has a predetermined discharge pressure of the discharge chamber according to the operation of the pressure switch 83. It is determined whether or not it is within the range.

  The variable displacement compressor according to the present embodiment is turned on when the discharge pressure Pd becomes equal to or higher than the second threshold Pd2, and the first pressure switch (not shown) is turned on when the discharge pressure Pd becomes lower than the first threshold Pd1. (Not shown) has a second pressure switch.

  Then, the compressor control unit 81 determines that the discharge pressure Pd is less than the first threshold Pd1 or the discharge pressure Pd is greater than or equal to the second threshold Pd2 when both of the first and second pressure switches are turned on in the determination of S102. It is determined that Furthermore, the compressor control unit 81 determines that the discharge pressure Pd is equal to or higher than the first threshold Pd1 and the discharge pressure Pd is the second threshold Pd2 when both of the first and second pressure switches are off in the determination of S102. Determined to be less than.

  Thus, in the determination of S102, the compressor control unit 81 determines whether the discharge pressure of the discharge chamber is within the predetermined range according to the operation of the pressure switch 83. Except for the determination in S102, the process is the same as the flowchart of FIG. 5, and thus the detailed description thereof is omitted here.

  In the present embodiment, the same effects obtained from the configuration common to the first embodiment can be obtained in the same manner as the first embodiment.

(Other embodiments)
(1) In each said embodiment, although the ball valve 700 was used as a valve body, as a kind of valve body, it is not limited to a ball valve.

(2) The variable displacement compressor according to the second embodiment includes the compressor control unit 81. The compressor control unit 81 controls the solenoid valve coil 750 in accordance with the program stored in the memory. On the other hand, the solenoid valve drive circuit 82 constitutes a circuit for controlling energization or de-energization of the solenoid valve coil 750 according to the operation of the pressure switch 83, and this circuit controls the solenoid valve coil 750. It is also good.
(3) In the above embodiments, the solenoid valve drive circuit 82 generates the PWM signal, and the current corresponding to the PWM signal is supplied to the solenoid valve coil 750. However, in the case of being limited to the PWM signal Alternatively, for example, the solenoid valve drive circuit 82 may output a level signal, and a current corresponding to the level signal may be supplied to the solenoid valve coil 750.

  In addition, this invention is not limited to above-described embodiment, In the range described in the claim, it can change suitably. Moreover, said each embodiment is not mutually irrelevant and can be combined suitably, unless the combination is clearly impossible. Further, in each of the above-described embodiments, it is needless to say that the elements constituting the embodiment are not necessarily essential except when clearly indicated as being essential and when it is considered to be obviously essential in principle. Yes. Further, in the above embodiments, when numerical values such as the number, numerical value, amount, range, etc. of constituent elements of the embodiment are mentioned, it is clearly indicated that they are particularly essential and clearly limited to a specific number in principle. It is not limited to the specific number except when it is done. Further, in the above embodiments, when referring to materials, shapes, positional relationships, etc. of constituent elements etc., unless specifically stated otherwise or in principle when limited to a specific material, shape, positional relationship, etc., etc. It is not limited to the material, the shape, the positional relationship, etc.

(Summary)
According to a first aspect of the present invention described in part or all of the above embodiments, the variable displacement compressor includes a suction chamber for sucking in fluid, a crank chamber for compressing fluid, and a discharge chamber for discharging compressed fluid. And a compressor housing having In addition, the variable displacement compressor has a valve member that opens and closes a communication passage that connects the discharge chamber and the crank chamber according to the suction pressure of the suction chamber, and the suction pressure of the suction chamber becomes the first pressure. The valve body includes a displacement control valve that controls the compression displacement by opening and closing the communication passage. Furthermore, the variable displacement compressor includes a discharge pressure detection unit that outputs a signal corresponding to the discharge pressure of the discharge chamber, and a control unit. In addition, the displacement control valve has a valve body drive unit for driving the valve body, and the control unit determines that the discharge pressure of the discharge chamber is within a predetermined range based on the signal output from the discharge pressure detection unit. In this case, the valve drive unit is controlled such that the suction pressure is a second pressure higher than the first pressure.

  Further, according to the second aspect, the valve body drive unit includes a movable body connected to the valve body and a solenoid valve coil for driving the movable body by an electromagnetic force, and the control unit is configured to discharge pressure When it is determined that the discharge pressure of the discharge chamber detected by the detection unit is within the predetermined range, the solenoid valve coil is controlled such that the valve body opens the communication passage.

As described above, the valve body drive unit includes the movable body connected to the valve body and the solenoid valve coil for driving the movable body by the electromagnetic force, and the control unit is detected by the discharge pressure detection unit. When it is determined that the discharge pressure of the discharge chamber is within the predetermined range, the solenoid valve coil can be controlled so that the valve body opens the communication passage. Further, according to the third aspect, the control unit If the discharge pressure of the fluid detected by the discharge pressure detection unit is equal to or higher than the first threshold and the discharge pressure of the fluid detected by the discharge pressure detection unit is less than a second threshold larger than the first threshold, the suction pressure The valve drive unit is controlled so that the second pressure is higher than the first pressure.

  As described above, the control unit causes the discharge pressure of the fluid detected by the discharge pressure detection unit to be equal to or higher than the first threshold, and the discharge pressure of the fluid detected by the discharge pressure detection unit to be the second threshold larger than the first threshold. When the pressure is lower than the above, the power saving operation can be realized by controlling the valve body drive unit such that the suction pressure becomes a second pressure higher than the first pressure.

  Further, according to the fourth aspect, the control unit is configured such that the discharge pressure of the fluid detected by the discharge pressure detection unit is less than the first threshold, or the discharge pressure of the fluid detected by the discharge pressure detection unit is the first threshold If the second threshold value is greater than the second threshold value, the valve body drive unit is controlled to open and close the communication passage in accordance with the suction pressure of the suction chamber so that the suction pressure of the suction chamber becomes the first pressure. Do.

  As described above, the control unit causes the discharge pressure of the fluid detected by the discharge pressure detection unit to be less than the first threshold, or the discharge pressure of the fluid detected by the discharge pressure detection unit to be the second threshold larger than the first threshold. When the above occurs, the valve body drive unit is controlled, and the valve body opens and closes the communication passage in accordance with the suction pressure of the suction chamber so that the suction pressure of the suction chamber becomes the first pressure. The compression volume can be controlled such that the suction pressure of the fluid is equal to the first pressure.

  Further, according to the fifth aspect, the displacement control valve has a first rod connected to one end of the bellows, one end of which is fixed to the valve body and the other end of which expands and contracts according to the suction pressure, A second rod connected and the other end connected to the other end of the bellows, and a spring member for attracting the second rod to the opposite side of the bellows side, the movable body being a spring by the electromagnetic force generated by the electromagnetic valve coil The valve body opens the communication passage by moving to the bellows side against the suction force of the member.

  As described above, the valve body can be configured to open the communication path by moving the movable body to the bellows side against the suction force of the spring member by the electromagnetic force generated by the electromagnetic valve coil.

  Further, according to the sixth aspect, the discharge pressure detection unit has a pressure sensor that detects the discharge pressure of the discharge chamber. Thus, the discharge pressure detection unit can be configured by the pressure sensor that detects the discharge pressure of the discharge chamber.

  Further, according to the seventh aspect, the discharge pressure detection unit has a pressure switch that is turned on and off according to the discharge pressure of the discharge chamber. Thus, the discharge pressure detection unit can be configured by the pressure switch that is turned on and off according to the discharge pressure of the discharge chamber.

  The correspondence between the configuration in the above embodiment and the configuration in the claims will be described. The ball valve 700 corresponds to a valve body, the discharge pressure sensor 80 and the pressure switch 83 correspond to a discharge pressure detection unit, and electromagnetic The valve coil 750 corresponds to a valve drive unit, and the solenoid valve drive circuit 82 corresponds to a control unit.

Reference Signs List 1 variable displacement compressor 10 compressor housing 110 crank chamber 120 cylinder chamber 14 suction chamber 15 discharge chamber 30 piston 60 swash plate 70 volume control valve 700 ball valve 750 solenoid valve coil 760 movable body 80 discharge pressure sensor 81 compressor control unit 82 Solenoid valve drive circuit

Claims (7)

A variable displacement compressor having a variable compression capacity, wherein
A compressor housing (10) having a suction chamber (14) for sucking fluid, a crank chamber (110) for compressing the fluid, and a discharge chamber (15) for discharging the compressed fluid;
It has a valve body (700) which opens and closes a communication passage (785) which connects the discharge chamber and the crank chamber according to the suction pressure of the suction chamber, and the suction pressure of the suction chamber becomes a first pressure A displacement control valve (70) for controlling the compression displacement by opening and closing the communication passage as described above;
A discharge pressure detection unit (80, 83) for outputting a signal according to the discharge pressure of the discharge chamber;
A controller (82),
The displacement control valve has a valve body drive unit (750) for driving the valve body,
When the control unit determines that the discharge pressure of the discharge chamber is within a predetermined range based on the signal output from the discharge pressure detection unit, the suction pressure of the suction chamber is higher than the first pressure The variable displacement compressor controls the valve body drive unit to have a second pressure. The valve body drive unit includes a movable body (760) connected to the valve body, and an electromagnetic valve coil (750) for driving the movable body by an electromagnetic force.
The control unit controls the solenoid valve coil such that the valve body opens the communication passage when it is determined that the discharge pressure of the discharge chamber detected by the discharge pressure detection unit is within a predetermined range. The variable displacement compressor according to claim 1.   The control unit is configured such that the discharge pressure of the fluid detected by the discharge pressure detection unit is equal to or higher than a first threshold (Pd1), and the discharge pressure of the fluid detected by the discharge pressure detection unit is greater than the first threshold The valve drive unit according to claim 1 or 2, wherein the valve drive unit is controlled such that the suction pressure of the suction chamber becomes a second pressure higher than the first pressure if the second threshold (Pd2) becomes too large. Capacity variable compressor.   The control unit is configured such that the discharge pressure of the fluid detected by the discharge pressure detection unit is less than a first threshold (Pd1), or the discharge pressure of the fluid detected by the discharge pressure detection unit is greater than the first threshold If the second threshold value (Pd2) is also greater, the valve drive unit is controlled so that the suction pressure in the suction chamber becomes the first pressure according to the suction pressure in the suction chamber. The variable displacement compressor according to any one of claims 1 to 3, wherein a valve body opens and closes the communication passage. A first rod (710) connected to one end of a bellows (720), one end of which is fixed to the valve body and the other end of which is expanded and contracted according to the suction pressure;
A second rod (745) having one end connected to the movable body and the other end connected to the other end of the bellows;
A spring member (770) for attracting the second rod to the side opposite to the bellows side;
The valve body opens the communication path by moving the movable body to the bellows side against the suction force of the spring member by the electromagnetic force generated by the electromagnetic valve coil. Variable displacement compressor according to one.   The variable displacement compressor according to any one of claims 1 to 5, wherein the discharge pressure detection unit includes a pressure sensor that detects a discharge pressure of the discharge chamber.   The variable displacement compressor according to any one of claims 1 to 5, wherein the discharge pressure detection unit has a pressure switch that is turned on and off according to the discharge pressure of the discharge chamber.

Images