JP2008031962A - Variable displacement compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent degradation of controllability of a compressor 1 in normal operation after start while improving startability of the compressor 1. <P>SOLUTION: A variable displacement compressor 1 comprises a pressure lead-in passage 62 establishing communication between a delivery chamber 8 and a crank chamber 5, a displacement control valve 64 put in a middle of the pressure lead-in passage 62 and opening and closing the pressure lead-in passage 62, a first pressure lead-out passage 66 always keeping communication between a crank chamber 5 and a suction chamber 7, a second pressure lead-out passage 68A establishing communication between the crank chamber 5 and the suction chamber 7, and a valve element 70 opening and closing the second pressure lead-out passage 68A. The valve element 70 moves by its own weight to open the second pressure lead-out passage 68A when the displacement control valve 64 is closed, and receives pressure in the pressure lead-in passage 62 and moves with resisting its own weight to open the second pressure lead-out passage 68A when the displacement control valve 64 is opened. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a variable capacity compressor that controls an inclination angle of a swash plate in accordance with a difference between a pressure in a crank chamber and a suction pressure through a piston.

  In recent years, variable capacity compressors have often been incorporated into cooling circuits used in vehicle air conditioning systems (see, for example, Patent Document 1 and Patent Document 2).

  This type of variable capacity compressor includes a cylinder block having a plurality of cylinder bores, a piston slidably accommodated in each cylinder bore, a front housing joined to the front end surface of the cylinder block and forming a crank chamber therein, and a cylinder A valve plate joined to the front end face of the block, a rear housing joined to the front end face of the cylinder block via a valve plate to form a suction chamber and a discharge chamber, and a drive housed rotatably in the crank chamber A shaft, a swash plate housed in the crank chamber for converting the rotation of the drive shaft into a reciprocating motion of each piston, and a capacity control means for controlling the piston stroke by controlling the inclination angle of the swash plate by adjusting the pressure in the crank chamber And.

  Here, the capacity control means includes a pressure introduction passage for introducing the pressure of the discharge chamber into the crank chamber, a capacity control valve which is interposed in the middle of the pressure introduction passage and opens and closes the pressure introduction passage, and sucks the pressure in the crank chamber. And a pressure outlet passage leading out to the chamber.

  In this variable capacity compressor, when the capacity control valve is opened and the pressure in the discharge chamber is introduced into the crank chamber, the back pressure acting on the piston increases, the inclination angle of the swash plate decreases, and the piston stroke decreases. As a result, the discharge capacity decreases. Also, when the capacity control valve is closed and the discharge chamber pressure is no longer introduced into the crank chamber, the back pressure acting on the piston drops, the tilt angle of the swash plate increases, the piston stroke increases, and the discharge capacity increases. To do.

The capacity control valve includes an electromagnetic type controlled by a control signal from the outside, and a mechanical type that is independently controlled by sensing the pressure in the cooling circuit or the compressor. For example, when the capacity control valve is a mechanical type that opens and closes by sensing the suction pressure, when the cooling load is small (that is, the temperature of the air passing through the evaporator is lower than the refrigerant flow rate flowing through the evaporator of the cooling circuit) When the suction pressure is reduced, the bellows as the pressure sensing portion is extended, the displacement control valve is opened, the discharge pressure is introduced into the crank chamber, the piston stroke is reduced, and the discharge capacity is reduced. Further, when the cooling load is large, the suction pressure becomes high, so that the bellows contracts and the capacity control valve is closed, and the discharge pressure is not introduced into the crank chamber, so that the piston stroke becomes large and the discharge capacity increases.
JP 2002-250277 A (FIG. 1) Japanese Patent No. 3289454

  By the way, in a conventional compressor, a large amount of liquid refrigerant accumulates in the crank chamber due to the state in which the vehicle is left while the compressor is stopped (outside air condition, etc.), and when the compressor is started next time, When it becomes difficult to pull out, the startability of the swash plate deteriorates (the swash plate start-up delay occurs), and it takes time to circulate the refrigerant in the cooling circuit. There was a problem that it took time.

  Therefore, if the passage sectional area of the pressure outlet passage from the crank chamber to the suction chamber is simply increased in order to quickly extract the liquid refrigerant from the crank chamber, the controllability during normal operation may be deteriorated. . That is, if the passage area of the pressure derivation passage is increased to improve the escape of liquid refrigerant, the amount of high-pressure refrigerant introduced from the discharge chamber to the crank chamber can be adjusted by adjusting the opening of the capacity control valve during normal operation. In addition to this, the pressure is gradually released from the crank chamber to the suction chamber through the pressure derivation passage, so the pressure in the crank chamber does not increase easily, and the crank chamber pressure does not increase even if the capacity control valve is opened. It takes time and the response is poor.

  In particular, when the heat load received by the evaporator becomes small (when the temperature of the air passing through the evaporator is low relative to the flow rate of refrigerant flowing through the evaporator), the discharge of the compressor To reduce the flow rate of refrigerant flowing through the evaporator by reducing the capacity to prevent freezing of the outer surface of the evaporator, but with a structure where the cross-sectional area of the pressure derivation passage is widened, the compressor has the minimum capacity. Since it is difficult to reduce the flow rate of refrigerant flowing through the evaporator during operation, the evaporator is likely to freeze.

  In view of the above circumstances, an object of the present invention is to provide a variable capacity compressor capable of maintaining controllability during normal operation after startup while improving startability.

  The present invention is a variable displacement compressor, wherein a cylinder bore in which a piston is reciprocally movable, a crank chamber communicating with the bottom dead center side of the cylinder bore, and a suction hole on the top dead center side of the cylinder bore are provided. A suction chamber that communicates with the cylinder bore via a discharge hole, a pressure introduction passage that communicates the discharge chamber and the crank chamber, and a middle portion of the pressure introduction passage. A capacity control valve that opens and closes the pressure introduction passage, a first pressure derivation passage that communicates the crank chamber and the suction chamber, and a second pressure derivation passage that communicates the crank chamber and the suction chamber. And a valve body that opens and closes the second pressure derivation passage, and the valve body moves due to its own weight when the capacity control valve is closed to open the second pressure derivation passage, When the capacity control valve is opened It is characterized by closing the second pressure discharge passage to move against its own weight under the pressure of the pressure introduction passage.

  According to the present invention, when the compressor is started, the valve body opens the second pressure derivation passage as the displacement control valve operates to the closed side, so that in addition to the first pressure derivation passage, The pressure in the crank chamber can also be released from the pressure outlet passage. Therefore, the pressure in the crank chamber can be released quickly by substantially increasing the passage cross-sectional area of the pressure derivation passage, the startability can be improved, and the cooling performance at the start can be improved.

  Further, during normal operation after startup, the capacity control valve is opened and its opening degree is adjusted, but the valve element closes the second pressure derivation passage as it operates on the open side of the capacity control valve. The pressure in the crank chamber is released only from the first pressure derivation passage. Therefore, since it becomes difficult for the pressure in the crank chamber to be released, the discharge capacity can be adjusted by adjusting the pressure in the crank chamber with a quick response in accordance with the adjustment of the opening of the capacity control valve. Therefore, according to the present invention, it is possible to maintain controllability during normal operation after startup while improving startability.

  In addition, according to the present invention, the valve body that opens and closes the second pressure derivation passage opens and closes due to the balance between the pressure of the pressure introduction passage and the weight of the valve body. Since the urging means is not required, the number of parts is reduced, leading to cost reduction.

  Preferred embodiments of the present invention will be described with reference to the drawings.

First Embodiment Hereinafter, a variable capacity compressor according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing the overall configuration of the variable capacity compressor of the first embodiment, FIG. 2 is a front view of the rear housing of the compressor, and FIG. 3 is an enlarged view of the main part of the capacity control means of the compressor. It is sectional drawing.

  As shown in FIG. 1, the variable capacity compressor 1 of the present embodiment is a swash plate type piston compressor. The housing of the compressor 1 includes a cylinder block 2 having a plurality of cylinder bores 3, a front housing 4 joined to the front end surface of the cylinder block 2 and forming a crank chamber 5 between the cylinder block 2, and a cylinder block 2 and a rear housing 6 that forms a suction chamber 7 and a discharge chamber 8 by being joined to each other through a valve plate 9. The cylinder block 2, the front housing 4, and the rear housing 6 are fixed by through bolts B.

  The valve plate 9 is formed through the valve plate 9 so as to allow the cylinder bore 3 and the discharge chamber 8 to communicate with a suction hole (not shown) formed through the valve plate 9 so as to communicate the cylinder bore 3 with the suction chamber 7. Discharge holes (not shown). A metal suction plate (not shown) having a reed valve portion (suction valve) for opening and closing the suction hole is provided on the cylinder block 2 side of the valve plate 9, while on the rear housing 6 side of the valve plate 9. Is provided with a metal discharge plate (not shown) having a reed valve portion (discharge valve) for opening and closing the discharge hole.

  Shaft support holes 2c and 4c are provided at the center of the cylinder block 2 and the front housing 4, and the drive shaft 10 is supported by the shaft support holes 2c and 4c via bearings 17 and 18, respectively. As a result, the drive shaft 10 is rotatable in the crank chamber 5. A front end of the drive shaft 10 protrudes from the front housing 4 to the outside, and a pulley 51 is fixed to the protruding end via an electromagnetic clutch 50. The pulley 51 is connected to the vehicle engine via a belt (not shown), receives the rotation of the engine, and transmits power to the drive shaft 10 via the electric clutch 50.

  Inside the crank chamber 5, a rotor 21 fixed to the drive shaft 10, a sleeve 22 slidably fitted to the drive shaft 10, and a sleeve 22 are pivotally connected via a pin 23. And a swash plate 24. The swash plate 24 is configured by combining a journal 25 attached to the sleeve 22 and a swash plate body 26 fixed to the boss portion of the journal 25. The rotor 21 and the swash plate 24 are connected via a link mechanism 40, whereby the rotor 21 and the swash plate 24 are integrally formed while the inclination angle of the swash plate 24 with respect to the drive shaft 10 can be changed. It is designed to rotate.

  The pistons 29 accommodated in the cylinder bores 3 are connected to the swash plate 24 via the piston shoes 30, and when the swash plate 24 rotates, the pistons move in the cylinder bores 3. The basic function of the compressor 1 is to suck the refrigerant from the suction chamber 7 into the cylinder bore 3 through the suction hole by the piston movement of the piston 29, compress the sucked refrigerant, and then from the cylinder bore 3 through the discharge hole. The discharge is performed in the discharge chamber 8.

  Here, the sleeve 22 is elastically supported by return springs 27 and 28 from both sides in the axial direction, and when the sleeve 22 moves toward the cylinder block against the return spring 27, the inclination angle of the swash plate 24 decreases. Conversely, when the sleeve 22 moves away from the cylinder block 2 against the return spring 28, the inclination angle of the swash plate 24 increases.

  If the inclination angle of the swash plate 24 is reduced, the piston stroke is reduced and the discharge capacity of the compressor 1 is reduced. Conversely, if the inclination angle of the swash plate 24 increases, the piston stroke increases and the discharge capacity of the compressor 1 increases.

Capacity control means In the compressor 1 of the present embodiment, a capacity control means 60 is provided to make the discharge capacity variable.

  The capacity control means 60 includes a pressure introducing passage 62 that communicates the crank chamber 5 and the discharge chamber 8, a capacity control valve 64 that controls opening and closing of the pressure introducing passage 62, and a first that communicates the crank chamber 5 and the suction chamber 7. The pressure derivation passage 66 and the second pressure derivation passage 68A are provided.

  When the opening degree of the pressure introduction passage 62 is adjusted by the capacity control valve 64, the flow rate of the high-pressure refrigerant flowing from the discharge chamber 8 to the crank chamber 5 through the pressure introduction passage 62 is adjusted, whereby the pressure in the crank chamber 5 is adjusted. Will be adjusted. When the pressure in the crank chamber 5 is adjusted, the pressure difference before and after the piston 29 (difference between the pressure in the suction chamber 7 and the pressure in the crank chamber 5) is adjusted, so that the piston stroke changes. As a result, the discharge capacity changes.

  Hereinafter, the capacity control means 60 of this embodiment will be described in more detail.

  The pressure introduction passage 62 includes an upstream portion 62a upstream of the displacement control valve 64 (on the discharge chamber 8 side) and a downstream portion downstream of the displacement control valve 64 (on the crank chamber 5 side). 62b. The high pressure of the discharge chamber 8 is applied to the upstream portion 62 a of the capacity control valve 64 regardless of whether the capacity control valve 64 is opened or closed. When the capacity control valve 64 is opened, the discharge chamber is passed through the downstream portion 62 b of the pressure introduction passage 62. A high pressure of 8 flows into the crank chamber 5.

  The pressure deriving passages 66 and 68A are provided for the refrigerant in the crank chamber 5 (the refrigerant introduced into the crank chamber 5 from the discharge chamber 8 through the pressure introducing passage 62 and the blow-by gas flowing into the crank chamber 5 from the cylinder bore 3 during the compression operation of the piston 29). Is returned to the suction chamber 7.

  A fixed throttle 66 a is provided in the middle of the first pressure derivation passage 66 to limit the flow rate of the refrigerant flowing from the crank chamber 5 to the suction chamber 7. The fixed throttle portion 66a is provided if the amount of refrigerant flowing through the first pressure derivation passage 66 (refrigerant flow rate fed back from the crank chamber 5 to the suction chamber 7) can be strictly controlled, and the crank chamber 5 and the suction chamber 7 are provided. This is because the pressure balance with the discharge chamber 8 can be maintained in a good state, and the discharge capacity of the compressor 1 can be easily controlled.

  The first pressure derivation passage 66 is arranged in the rear of the cylinder block 2 so as to surround the through hole 66a as the fixed restricting portion formed through the valve plate 9 and the rear end portion of the drive shaft 10 that are sequentially communicated with each other. A space 66b formed in the end face, a longitudinal opening 66c in the shaft extending in the axial direction inside the drive shaft 10 with one end opening in the space 66b, and extending in the radial direction of the drive shaft 10 from the vertical hole 66c. The shaft inner side hole 66d that faces the space in the crank chamber 5 by opening in the outer peripheral surface of the drive shaft 10 is formed.

  The reason why the shaft inner vertical hole 66 c and the shaft inner horizontal hole 66 d constituting the first pressure derivation passage 66 are provided in the drive shaft 10 is that the refrigerant gas is led out from the crank chamber 5 to the suction chamber 7. The mist-like lubricating oil accompanying the refrigerant gas is trapped in the shaft inner side hole 66d and is pushed back to the crank chamber 5 by the centrifugal force generated by the rotation of the drive shaft 10 as it is. This is because the amount of lubricating oil stored in the crank chamber 5 to flow out of the crank chamber 5 for lubrication can be reduced.

  In this example, the second pressure derivation passage 68 </ b> A does not directly communicate with the crank chamber 5 and the suction chamber 7, but communicates the downstream portion 62 b of the pressure introduction passage 62 with the suction chamber 7. Indirect communication with the suction chamber 7.

  In the middle of the downstream portion 62b of the pressure introducing passage 62, there is a connecting portion (intersection portion) 72 between the downstream portion 62b of the pressure introducing passage 62 and the second pressure deriving passage 68A. The downstream portion 62 b of the pressure introduction passage 62 includes a first passage portion 62 b 1 closer to the crank chamber 5 than the connecting portion (intersection point) 72 and a second portion closer to the capacity control valve 64 than the connecting portion (intersection point) 72. The passage portion 62b2 can be divided and viewed.

  In the present embodiment, a valve body 70 for opening and closing the pressure derivation passage 82A is provided. The valve body 70 is disposed in the downstream portion 62b of the pressure introduction passage 62, and includes a first passage portion 62b1 of the pressure introduction passage, a second passage portion 62b2 of the pressure introduction passage, and a second pressure derivation passage 68A. A flow path switching function for communicating and blocking the three passages 62b1, 62b2, and 68A is provided.

  The flow path switching operation of the valve body 70 is linked to the opening / closing operation of the capacity control valve 64, and the valve body 70 is connected to the second pressure derivation passage 68A when the capacity control valve 64 is operated to the closed side. Is opened, and the second pressure derivation passage 68A is closed when the displacement control valve 64 is operated to the open side.

  Hereinafter, the flow path switching structure of the valve body 70 will be described in more detail.

  The valve body 70 has a first switching position (FIG. 4) that has entered the second passage portion 62 b 2 closer to the capacity control valve 64 than the connecting portion 72, and a second pressure that is closer to the suction chamber 7 than the connecting portion 72. It is slidable across the second switching position (FIG. 5) entering the lead-out passage 68A. That is, the valve chamber 71 that accommodates the valve body 70 sandwiches the connecting portion 72, and the first switching position on the capacity control valve 64 side (FIG. 4) and the second switching position on the suction chamber 7 side (FIG. 5). Are provided.

  The valve chamber 71 has an inner peripheral surface formed in a straight line with substantially the same cross-sectional area as the valve body 70, and the first switching position (FIG. 4) is the first switching position so that the self-weight of the valve body 70 can be used. 2 is provided below the switching position (FIG. 5). In this example, the valve chamber 71 is provided with an inclination of approximately 45 ° with respect to the horizontal plane. The valve chamber 71 is preferably provided with an inclination of 45 ° or more and 90 ° or less with respect to the horizontal plane so that the weight of the valve body 70 can be used effectively.

  When the valve body 70 is moved to the first switching position from the connecting portion 72 (FIG. 4), the valve body 70 blocks the communication between the first passage portion 62b1 and the second passage portion 62b2 and the first passage portion 62b1. The passage portion 62b1 communicates with the second pressure outlet passage 68A. Conversely, when the valve body 70 moves to the second switching position from the connecting portion 72 (FIG. 5), the valve body 70 blocks the second pressure derivation passage 68A and the first passage portion 62b1 and the second passage portion 62b1. The passage portion 62b2 communicates with the passage portion 62b2.

  When the capacity control valve 64 is closed, the valve body 70 moves downward due to its own weight and is positioned at the first switching position (FIG. 4). When the capacity control valve 64 is opened, the valve body 70 is moved to the pressure introduction passage. Under the pressure of 62, it moves toward the upper second switching position (FIG. 5) against its own weight. Thus, the valve body 70 opens the second pressure derivation passage 68A when the displacement control valve 64 is actuated to the closed side, and the second pressure derivation passage when the displacement control valve 64 is actuated to the open side. 68A is closed.

  Here, the stopper that stops the valve body 70 at the second switching position is constituted by a sleeve (cylindrical member) 76 that is internally fitted (press-fitted and fixed) in the passage.

  The sleeve 76 is formed of resin or metal, for example. The sleeve 76 also functions as a fixed restricting portion that restricts the passage cross-sectional area of the second pressure derivation passage 68A in which the sleeve 76 is fitted, as compared with other portions of the second pressure derivation passage 68A.

  Next, the operation will be described.

  In the compressor 1, when the capacity control valve 64 is opened and the pressure of the discharge chamber 8 is introduced into the crank chamber 5, the inclination of the swash plate 24 is reduced due to the increase of the back pressure acting on the piston 29, and the piston stroke. Decreases and the discharge capacity decreases. On the contrary, when the capacity control valve 64 is closed and the pressure of the discharge chamber 8 is not introduced into the crank chamber 5, the inclination of the swash plate 24 increases due to the fall of the back pressure acting on the piston 29, and the piston stroke increases. As a result, the discharge capacity increases.

  The displacement control valve 64 may be an electromagnetic (external control) control valve or a mechanical (self-supporting) control valve that is independently controlled by a pressure-sensitive portion such as a bellows. For example, the capacity control valve 64 senses the low pressure of the cooling circuit (the pressure of the refrigerant downstream of the evaporator and upstream of the compressor 1 = the pressure of the suction chamber in the compressor 1) with a pressure sensing part such as a bellows. In the case of a mechanical type that is independently controlled, the bellows expands and opens when the pressure in the suction chamber 7 decreases, and the bellows expands and contracts when the pressure in the suction chamber 7 increases. ing.

  As a result, when the cooling load is small (when the temperature of the air passing through the evaporator is low relative to the flow rate of refrigerant flowing through the evaporator), the amount of refrigerant evaporating in the evaporator decreases and the pressure in the suction chamber 7 is reduced. Therefore, the bellows expands, the capacity control valve 64 opens, the pressure in the discharge chamber 8 is introduced into the crank chamber 5, the piston stroke becomes small, and the discharge capacity decreases.

  Conversely, when the cooling load is large (when the temperature of the air passing through the evaporator is high relative to the flow rate of refrigerant flowing through the evaporator), the amount of refrigerant evaporated in the evaporator increases and the pressure in the suction chamber 7 increases. Therefore, the bellows contracts, the capacity control valve 64 closes, the pressure in the discharge chamber 8 is not introduced into the crank chamber 5, the piston stroke increases, and the discharge capacity increases.

  Here, when starting the stopped compressor, the compressor is started in a state where the capacity control valve 64 is closed, so that the introduction of the discharge pressure into the crank chamber 5 is stopped. Therefore, as shown in FIG. 4, when the valve body 70 is located at the first switching position by its own weight, the first passage portion 62b1 of the pressure introduction passage 62 and the second pressure derivation passage 68A communicate with each other. Accordingly, the pressure in the crank chamber 5 can be released from the second pressure deriving passage 68A in addition to the first pressure deriving passage 66 that is always open, so that the liquid refrigerant accumulated in the crank chamber 5 when the compressor is stopped. Exit quickly. Therefore, the start-up delay of the compressor 1 is eliminated, and it takes less time to cool the evaporator of the cooling circuit.

  In a state where the compressor 1 is normally operated after the start-up, the capacity control valve 64 is opened and its opening degree is controlled. When the capacity control valve 64 is opened and the pressure in the pressure introduction passage 62 increases, the valve body 70 is positioned at the second switching position against its own weight as shown in FIG. Is opened and the second pressure outlet passage 68A is closed. Accordingly, the pressure in the discharge chamber 8 is introduced into the crank chamber 5 through the pressure introduction passage 62, the inclination angle of the swash plate 24 is adjusted, and the piston stroke is adjusted. At this time, since the second pressure deriving passage 68A is closed by the valve body 70, the pressure in the crank chamber 5 is released only through the first pressure deriving passage 66. Therefore, since the pressure in the crank chamber 5 does not escape from the second pressure derivation passage 68A, the pressure in the crank chamber 5 can be controlled relatively quickly according to the adjustment of the opening of the capacity control valve 64.

  Therefore, according to the present embodiment, it is possible to maintain the controllability in the normal operation after the start-up while improving the startability at the time of starting the compressor.

  Here, in the structure in which the passage sectional area of the pressure derivation passage is simply widened without adopting the structure as in the present embodiment, when the heat load applied to the evaporator becomes considerably small (through the evaporator) (When the temperature of the air passing through the evaporator is considerably lower than the flow rate of the refrigerant), even if the capacity control valve 64 is fully opened, the passage from the pressure deriving passage having a wide passage sectional area to the crank chamber There is a risk that the outer surface of the evaporator will freeze without being able to achieve the minimum capacity operation. However, in this embodiment, there is no concern about such freezing of the evaporator.

  When the pressure in the pressure introduction passage 62 is not so high (for example, when the valve opening degree of the capacity control valve 64 is very small), the valve body 70 moves to the dotted line position in FIG. The inlet passage 62 leaks from the upstream side to the downstream side.

  Next, the main effects of this embodiment are listed.

  (1) The variable capacity compressor 1 of the present embodiment has a pressure introduction passage 62 that connects the discharge chamber 8 and the crank chamber 5, and a capacity that is interposed in the middle of the pressure introduction passage 62 to open and close the pressure introduction passage 62. A control valve 64, a first pressure derivation passage 66 that always communicates the crank chamber 5 and the suction chamber 7, a second pressure derivation passage 68A that communicates the crank chamber 5 and the suction chamber 7, and a second pressure And a valve body 70 for opening and closing the outlet passage 68A. The valve body 70 moves due to its own weight when the capacity control valve 64 is closed, and opens the second pressure derivation passage 68A. When the capacity control valve 64 is opened, the valve body 70 receives the pressure of the pressure introduction passage 62 and moves against its own weight. Then, the second pressure outlet passage 68A is closed.

  Therefore, when the compressor 1 is started, the second pressure deriving passage 68A is opened as the displacement control valve 64 is operated to the closed side. Therefore, in addition to the first pressure deriving passage 66, the second pressure deriving passage 66 is opened. The pressure in the crank chamber 5 can also be released from the pressure outlet passage 68A. Therefore, the pressure in the crank chamber 5 can be quickly released by substantially increasing the passage sectional area of the pressure derivation passage, and the startability of the compressor 1 can be improved. Further, when the displacement control valve 64 is opened during normal operation after startup, the second pressure derivation passage 68A is closed by the valve body 70, so that only the first pressure derivation passage 66 in the crank chamber 5 is closed. The pressure will be released. Therefore, during normal operation after startup, the pressure in the crank chamber 5 does not become insufficient because the pressure in the crank chamber 5 is difficult to be released. Therefore, the pressure in the crank chamber 5 can be controlled relatively quickly according to the opening adjustment of the capacity control valve 64.

  Therefore, according to the present embodiment, the startability of the compressor 1 is improved, and the controllability during normal operation after the start-up is not reduced.

  In addition, in the present embodiment, the valve body 70 that opens and closes the second pressure derivation passage 68A opens and closes according to the balance between the pressure of the pressure introduction passage 62 and the weight of the valve body 70. There is no need for a biasing means such as a spring for biasing in the direction, reducing the number of parts and reducing the cost.

  (2) In the variable capacity compressor 1 of the present embodiment, the second pressure derivation passage 68A includes the first pressure derivation passage 66 or the suction chamber 7 (the suction chamber 7 in this example) and the pressure introduction passage 62. The crank chamber 5 and the suction chamber 7 are communicated with each other by communicating with the downstream portion 62b closer to the crank chamber 5 than the capacity control valve 64. With this configuration, the downstream portion 62b of the pressure introduction passage 62 is not only used for pressure introduction, but also used for pressure derivation when not used for pressure introduction.

  Therefore, in the present embodiment, the second pressure derivation passage 68A can be shortened. Thus, if the 2nd pressure derivation | leading-out path | route 68A becomes short, the processing amount of a hole will reduce and manufacturing cost will be reduced further.

  (3) In the variable displacement compressor 1 of the present embodiment, the valve body 70 enters the second passage portion 62b2, thereby blocking communication between the first passage portion 62b1 and the second passage portion 62b2. The first switching position (FIG. 4) that connects the first passage portion 62b1 and the second pressure deriving passage 68A, and the second pressure deriving passage 68A are shut off by entering the second pressure deriving passage 68A. It moves across the second switching position (FIG. 5) that connects the first passage portion 62b1 and the second passage portion 62b2. The valve body 70 is positioned at the first switching position (FIG. 4) due to its own weight when the capacity control valve 64 is closed, and receives the pressure of the pressure introduction passage 62 when the capacity control valve 64 is opened. It moves against its own weight toward the position (FIG. 5).

  Therefore, since the valve body 70 is disposed in the middle of the pressure introduction passage 62 and the pressure of the pressure introduction passage 62 is applied, it is necessary to separately provide a passage for applying the pressure of the pressure introduction passage 62 to the valve body 70. Therefore, the structure is simplified and the manufacturing cost can be reduced.

  (4) Further, in the variable capacity compressor 1 of the present embodiment, the valve chamber 71 that slidably accommodates the valve body 70 has the first switching position on the capacity control valve 64 side (FIG. 4) with the connecting portion 72 interposed therebetween. ) And the second switching position (FIG. 5) on the suction chamber 7 side so that the first switching position (FIG. 4) is located below and the second switching position (FIG. 5) is located above. It is formed in a straight line. Therefore, the valve body 70 moves smoothly.

  (5) In this embodiment, the valve chamber 71 that slidably accommodates the valve body 70 is inclined by approximately 45 ° with respect to the horizontal plane. However, in the present invention, the valve chamber 71 is 45 with respect to the horizontal plane. It preferably has an inclination of not less than ° and not more than 90 °. This is because the self-weight of the valve body 70 can be sufficiently utilized at such an angle.

  (6) In the variable capacity compressor 1 of the present embodiment, the stopper that stops the valve body 70 at the second switching position (FIG. 5) is a sleeve 76 that is fitted (press-fit) into the passage. . Therefore, the stopper can be manufactured with a simple configuration. In this embodiment, the stopper for stopping the valve body 70 at the second switching position (FIG. 5) is constituted by the sleeve 76. Of course, the valve body is at the first switching position (FIG. 4). The stopper to be stopped can be constituted by a sleeve.

  (7) In the variable capacity compressor 1 of the present embodiment, the sleeve 76 has a passage cross-sectional area of a passage (in this example, the second pressure derivation passage 68A) in which the sleeve 76 is fitted, It is configured as a fixed restricting portion that restricts the passage cross-sectional area of the portion. Therefore, the cost of the fixed throttle portion can be reduced as compared with the case of separately drilling holes.

  (8) As shown in FIG. 6 (a), the passage cross-sectional area of the fixed restrictor may be set by adjusting the thickness of the sleeve 76A, or as shown in FIG. 6 (b). As described above, the passage cross-sectional area of the fixed throttle portion may be set by integrally providing the orifice plate 77 having the orifice hole 77a constituting the fixed throttle portion in the sleeve 76B.

  (9) In the variable capacity compressor 1 of the present embodiment, the upstream portions 66 c and 66 d of the first pressure derivation passage 66 are formed inside the drive shaft 10, and the upstream end of the first pressure derivation passage 66. 66d is open to the outer peripheral surface of the drive shaft 10 at a position where it is exposed to the crank chamber 5. Therefore, when the refrigerant gas is led out from the crank chamber 5 to the suction chamber 7, mist-like lubricating oil accompanying the refrigerant is captured in the shaft inner side hole 66 d and is directly used by the rotational centrifugal force of the drive shaft 10. It is pushed back into the crank chamber 5. Therefore, the amount of lubricating oil stored in the crank chamber 5 to flow out of the crank chamber 5 to lubricate the sliding parts in the crank chamber 5 can be reduced.

  Hereinafter, other embodiments will be described. In the following description, the same components as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description of the configuration and the operation and effect thereof are omitted.

(Second Embodiment)
Next, the variable capacity compressor 1 of 2nd Embodiment of this invention is demonstrated, referring FIGS. 7-12.

  In the first embodiment described above, the second pressure derivation passage 68 </ b> A communicates with the suction chamber 7 and the crank chamber 5 indirectly by connecting the downstream portion 62 b of the pressure introduction passage 62 and the suction chamber 7. However, in the second embodiment, the pressure introduction passage 62 has a structure that directly communicates with the suction chamber 7 and the crank chamber 5.

  In the second embodiment, a communication passage 80 is provided that communicates the middle of the downstream portion 62b on the crank chamber side with respect to the capacity control valve 64 in the pressure introduction passage 62 and the middle of the second pressure derivation passage 68B. It has been.

  For this reason, the second pressure derivation passage 68 </ b> B is connected to the first passage portion 68 </ b> B <b> 1 on the crank chamber side from the connection portion 84 and the connection portion 84 when the connection portion (intersection portion) 84 with the communication passage 80 is a boundary. It can be divided into the second passage portion 68B2 on the suction chamber side. Further, the downstream portion 62b of the pressure introduction passage 62 is connected to the first passage portion 62b1 on the crank chamber 5 side with respect to the connection portion 82 and the connection portion when the connection portion (intersection point) 82 with the communication passage 80 is a boundary. 82 and the second passage portion 62b2 on the capacity control valve 64 side.

  A valve body 70 is accommodated in the communication path 80. The valve body 70 has a first switching position (FIG. 10) that enters the downstream portion 62b of the pressure introduction passage 62 from the communication passage 80, and a second switching position that enters the second pressure derivation passage 68B from the communication passage 80. (FIG. 12).

  In the first switching position (FIG. 10), the valve body 70 closes the pressure introduction passage 62 and opens the second pressure derivation passage 68B. On the other hand, in the second switching position (FIG. 12), the valve body 70 blocks the second pressure derivation passage 68B and opens the pressure introduction passage 62.

  Further, between the first switching position (FIG. 10) and the second switching position (FIG. 12), the valve body 70 is retreated from both the pressure introduction passage 62 and the second pressure derivation passage 68B. There is a third switching position (FIG. 11) located in the passage 80. In the third switching position (FIG. 11), both the pressure introduction passage 62 and the second pressure derivation passage 68B are opened. In the figure, reference numeral 86 denotes a check valve.

  The communication path 80 constitutes a valve chamber that slidably accommodates the valve body 70, and has an inner peripheral surface that is substantially the same cross-sectional area as the valve body 70 and has a second switching position from the first switching position (FIG. 10). It is formed linearly over the switching position (FIG. 12). The communication path 80 is provided with a first switching position (FIG. 10) on the lower side and a second switching position (FIG. 12) on the upper side in order to use the dead weight of the valve body 70. The communication path 80 is provided with an inclination of approximately 45 ° with respect to the horizontal plane. The communication passage 80 is preferably provided with an inclination of 45 ° or more and 90 ° or less with respect to the horizontal plane in order to effectively use the weight of the valve body 70.

  Thus, in order to move the valve body 70 from the first switching position (FIG. 10) to the second switching position (FIG. 12), it is necessary to move against its own weight, but in this example, as described above, When the communication passage 80 is connected to the downstream portion 62b of the pressure introduction passage 62, the valve body 70 receives the pressure of the pressure introduction passage 62 when the capacity control valve 64 is opened, and is in the second switching position (FIG. 12). It is designed to move against its own weight.

  In the second embodiment, the valve body 70 enters the second passage portion 68B2 of the second pressure derivation passage 68B from the communication passage 80 at the second switching position of the valve body 70 (FIG. 12). Thus, the second pressure derivation passage 68B is blocked, and the first passage portion 68B1 of the second pressure derivation passage and the pressure introduction passage 62 are communicated with each other via the communication passage 80.

  According to such 2nd Embodiment, there exist the following effects.

  (1) The variable capacity compressor 1 of the second embodiment opens and closes the pressure introduction passage 62 that is interposed in the middle of the pressure introduction passage 62 and the pressure introduction passage 62 that communicates the discharge chamber 8 and the crank chamber 5. A capacity control valve 64; a first pressure derivation passage 66 that always communicates the crank chamber 5 and the suction chamber 7; a second pressure derivation passage 68B that communicates the crank chamber 5 and the suction chamber 7; And a valve body 70 for opening and closing the pressure outlet passage 68B. When the capacity control valve 64 is closed, the valve body 70 moves by its own weight to open the second pressure derivation passage 68B, and when the capacity control valve 64 is opened, the valve body 70 receives the pressure of the pressure introduction passage 62 and moves against its own weight. Then, the second pressure outlet passage 68B is closed.

  Therefore, the same effect as the effect (1) of the first embodiment can be obtained.

  (2) In the variable capacity compressor 1 of the second embodiment, the communication passage 80 that connects the downstream portion 62b on the crank chamber side with respect to the displacement control valve 64 in the pressure introduction passage 62 and the second pressure derivation passage 68B. The valve body 70 is accommodated in the communication passage 80, and the valve body 70 has a first switching position (FIG. 10) that has entered the downstream portion 62b of the pressure introduction passage 62 from the communication passage and a second passage from the communication passage. And a second switching position (FIG. 12) that enters the pressure derivation passage 68B. Therefore, if the valve body 70 is located at the first switching position (FIG. 10), the pressure introduction passage 62 is closed and the second pressure derivation passage 68B is opened, and the valve body 70 is moved to the second switching position ( 12), the second pressure derivation passage 68B is blocked and the pressure introduction passage 62 is opened. The valve body 70 is positioned at the first switching position (FIG. 10) due to its own weight when the capacity control valve 64 is closed, and receives the pressure of the pressure introduction passage 62 when the capacity control valve 64 is opened. It moves against its own weight toward the switching position (FIG. 12).

  That is, with the simple configuration in which the pressure introduction passage 62 and the second pressure derivation passage 68B are communicated with each other and the communication passage 80 that accommodates the valve body 70 is formed, the above-described configuration can be achieved without adding any other special structure. The effect (1) can be obtained.

  (3) In the variable capacity compressor 1 of the second embodiment, the valve body 70 enters the second passage portion 68B2 of the second pressure derivation passage 68B at the second switching position (FIG. 12). The second pressure derivation passage 68B is shut off, and the first passage portion 68B1 of the second pressure derivation passage and the pressure introduction passage 62 are communicated with each other via the communication passage 80.

  Therefore, when the capacity control valve 64 is opened and the pressure introduction passage 62 is opened, in addition to the pressure introduction passage 62, a part 68 B 1 of the second pressure derivation passage 68 B is also utilized, and the pressure in the discharge chamber 8 is transferred to the crank chamber 5. Can be introduced. Therefore, when the capacity control valve 64 is opened, the pressure in the crank chamber 5 can be quickly increased (response is quickened), and the controllability is further improved.

  (4) In the variable capacity compressor 1 of the second embodiment, the valve body 70 is located between the first switching position (FIG. 10) and the second switching position (FIG. 12). There is a third switching position (FIG. 11) that opens both of the pressure introducing passage 62 and the second pressure leading passage 68B by retreating from both the second pressure leading passage 68B. As a result, when the pressure in the pressure introduction passage 62 is not so high (for example, when the valve opening degree of the capacity control valve 64 is small), the valve body 70 moves to the third switching position (FIG. 11). Both the introduction passage 62 and the second pressure outlet passage 68B are opened.

  The present invention is not limited to the above embodiment, and can be modified without departing from the technical idea of the present invention.

FIG. 1 is a sectional view showing the overall configuration of a variable capacity swash plate compressor according to a first embodiment of the present invention. FIG. 2 is a front view of a rear housing of the compressor. FIG. 3 is an enlarged sectional view of a main part of the capacity control means of the compressor. FIG. 4 is an enlarged cross-sectional view of the main part of the capacity control means of the compressor, showing the position of the valve body when the capacity control valve 64 is closed. FIG. 5 is an enlarged cross-sectional view of the main part of the capacity control means of the compressor, showing the position of the valve body when the capacity control valve 64 is open. 6A and 6B are views showing a modification of the sleeve of the capacity control means of the compressor. FIG. 7 is a cross-sectional view showing the overall configuration of a variable capacity swash plate compressor according to a second embodiment of the present invention. FIG. 8 is a front view of a rear housing of the compressor. FIG. 9 is an enlarged sectional view of a main part of the capacity control means of the compressor. FIG. 10 is an enlarged cross-sectional view of the main part of the capacity control means of the compressor, showing the position of the valve body when the capacity control valve 64 is closed. FIG. 11 is an enlarged cross-sectional view of the main part of the capacity control means of the compressor, showing the position of the valve body when the capacity control valve 64 is slightly opened. FIG. 12 is an enlarged cross-sectional view of the main part of the capacity control means of the compressor, and is a view showing the position of the valve body when the capacity control valve 64 is fully opened.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Variable capacity compressor 5 ... Crank chamber 7 ... Suction chamber 8 ... Discharge chamber 29 ... Piston 62 ... Pressure introduction passage 62a ... Upstream portion 62b ... Downstream portion 62b1 ... First passage portion 62b2 ... Second passage portion 64 ... Capacity control valve 66 ... first pressure outlet passage 66a ... through hole (fixed restrictor)
68A ... second pressure outlet passage 68B ... second pressure outlet passage 68B1 ... first passage portion 68B2 ... second passage portion 70 ... valve element 72 ... connecting portion (downstream portion of pressure introduction passage and second pressure Intersection with the introduction passage)
80 passage
82 Connecting part (intersection of the downstream part of the pressure introduction passage and the communication passage)
84 connecting portion (intersection of second pressure derivation passage and communication passage)

Claims (5)

A cylinder bore (3) in which a piston (29) is reciprocally movable, a crank chamber (5) communicating with the bottom dead center side of the cylinder bore (3), and suction into the top dead center side of the cylinder bore (3) A suction chamber (7) communicating through a hole, a discharge chamber (8) communicating via a discharge hole to the top dead center side of the cylinder bore, the discharge chamber (8), and the crank chamber (5). A pressure introduction passage (62) that communicates, a capacity control valve (64) that is interposed in the middle of the pressure introduction passage (62) to open and close the pressure introduction passage (62), the crank chamber, and the suction chamber. A first pressure derivation passage (66) that communicates, a second pressure derivation passage (68A, 68B) that communicates the crank chamber and the suction chamber, and a second pressure derivation passage (68A, 68B). And a valve body (70) that opens and closes,
The valve body (70) moves due to its own weight when the capacity control valve (64) is closed to open the second pressure derivation passages (68A, 68B), and when the capacity control valve (64) is opened. The variable displacement compressor is characterized in that it receives the pressure of the pressure introduction passage (62) and moves against its own weight to close the second pressure derivation passages (68A, 68B). The variable capacity compressor according to claim 1,
The second pressure derivation passage (68A) is more than the first pressure derivation passage (66) or the suction chamber (7) and the capacity control valve (64) in the pressure introduction passage (62). The variable capacity compressor characterized in that the crank chamber (5) and the suction chamber (7) are communicated with each other by communicating with the downstream portion (62b) on the crank chamber (5) side. . The variable capacity compressor according to claim 2,
The valve body (70) is slidably disposed in the vicinity of a connection portion (72) between the downstream portion (62b) of the pressure introduction passage (62) and the second pressure derivation passage (68A), and the connection A first passage portion (62b1) closer to the crank chamber than the portion (72), a second passage portion (62b2) closer to the capacity control valve than the connection portion (72), and the connection portion (72). The flow path of the three passages (62b1, 62b2, 68A) of the second pressure derivation passage (68A) closer to the suction chamber is switched,
The valve body (70) communicates between the first passage portion (62b1) and the second passage portion (62b2) by entering the second passage portion (62b2) from the connecting portion (72). And a first switching position where the first passage portion (62b1) and the second pressure derivation passage (68A) communicate with each other, and the second pressure derivation passage ( 68A), the second switching position that blocks the second pressure derivation passage (68A) and communicates the first passage portion (62b1) and the second passage portion (62b2); Movably provided over the
The valve body (70) is positioned at the first switching position by its own weight when the capacity control valve (64) is closed, and the pressure of the pressure introduction passage (62) is increased when the capacity control valve (64) is opened. A variable capacity compressor that receives and moves against its own weight toward the second switching position. The variable capacity compressor according to claim 1,
Of the pressure introduction passage (62), a communication passage (80) communicating the downstream portion (62b) on the crank chamber side with respect to the capacity control valve (64) and the second pressure derivation passage (68B). With
The valve body (70) is accommodated in the communication passage (80),
The valve body (70) enters the downstream portion (62b) of the pressure introduction passage (62) from the communication passage and opens the second pressure derivation passage (68B), and the communication position. A second switching position that enters the second pressure derivation passage (68B) from the passage, shuts off the second pressure derivation passage (68B), and opens the pressure introduction passage (62). Provided freely,
The valve body (70) is positioned at the first switching position by its own weight when the capacity control valve (64) is closed, and the pressure of the pressure introduction passage (62) when the capacity control valve (64) is opened. And a variable capacity compressor characterized by moving against the dead weight toward the second switching position. The variable capacity compressor according to claim 4,
The second pressure derivation passage (68B) is a first passage portion (68B1) closer to the crank chamber than a connecting portion (84) between the communication passage (80) and the second pressure derivation passage (68B). And a second passage portion (68B2) closer to the suction chamber than the connecting portion (84),
In the second switching position, the valve body (70) enters the second passage portion (68B2) of the second pressure derivation passage (68B), thereby causing the second pressure derivation passage (68B). And the first passage portion (68B1) of the second pressure derivation passage and the pressure introduction passage (62) are communicated with each other through the communication passage (80). Compressor.

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