JP2000291542A - Control valve for variable displacement type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control valve allowing accurate setting of a set suction pressure, without being affected by a pressure in a crank chamber of a variable displacement type compressor. SOLUTION: In this control valve, a valve seat 54 partitions a passage chamber 53, formed in a valve housing 51 into an upper crank chamber side area 53a and a lower suction chamber side area 53b, while a valve element 60 disposed in the crank chamber side area 53a is elastically supported by first spring mechanisms 61, 62 which energize the valve element 60 in the seating direction onto the valve seat 54 and second spring mechanisms 74, 75, 76 to energize the valve element 60 to the separating direction from the valve seat 54. A bellows 61, capable of displacement in response to a crank pressure Pc, is provided in the crank chamber side area 53a. The effective area of the bellows 61 is set nearly equal to a bore diameter area of the suction chamber side area 53b (i.e., the sealing area of the valve element 60).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control valve for a variable displacement compressor, and more particularly to a variable displacement type swash plate system capable of changing a discharge displacement by controlling an internal pressure of a crank chamber containing a tiltable swash plate. The present invention relates to a control valve used for a compressor.

[0002]

2. Description of the Related Art There is known a variable displacement swash plate type compressor in which the displacement of a compressor can be changed by controlling the angle of a swash plate provided in a crank chamber inside a compressor so as to be tiltable. In this type of compressor, the swash plate angle is appropriately adjusted by adjusting the refrigerant gas pressure (crank pressure Pc) filled in the crank chamber by using a special control valve. For example,
Japanese Patent Laying-Open No. 6-26454 discloses a vent-side control valve provided in the middle of a bleed passage connecting a crank chamber of a compressor and a suction chamber (communicating with an outlet side of an evaporator). In the removal side control valve, the set suction pressure is made variable by controlling the amount of electricity supplied to the electromagnetic coil, and the suction pressure Ps is guided to a room containing the bellows and the valve element attached to the movable end thereof. Then, the valve body is moved toward and away from the valve port (valve hole) for communicating the crank chamber with the suction chamber in accordance with the suction pressure Ps to control the opening degree of the control valve, and the gas from the crank chamber is controlled. The crank pressure Pc is controlled autonomously by adjusting the release amount. In this valve structure, the valve body tries to close the valve port (valve hole) by the urging action of the bellows itself, whereas the crank pressure Pc acts in a direction to separate the valve element from the valve port.

[0003]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 6-264.
In paragraph No. 0018 of JP-A-54, the balance of the forces acting on the actuating mechanism including the valve element in the withdrawal side control valve is considered. Assuming that an equation is established from an equation relating to an upward force and an equation relating to a downward force shown in the paragraph, and the equation is arranged into an equation in which the suction pressure Ps is on the left side, the P
The right side of the s expression always includes the term of the crank pressure Pc. In other words, even if the set suction pressure Pset is uniquely determined based on the control of the amount of current to the electromagnetic coil, the suction pressure Ps
Is always affected by the crank pressure Pc. That is, in the removal side control valve, the crank pressure Pc that variously changes depending on the operating condition of the compressor is inevitably a disturbance factor of the suction pressure Ps due to a structural factor of the valve itself. For this reason,
It is difficult to improve the variable accuracy of the set suction pressure Pset, no matter how accurate the control of the energization amount to the electromagnetic coil is.

An object of the present invention is to provide a variable displacement swash plate compressor capable of accurately setting a set suction pressure without being affected by the pressure (Pc) of a crank chamber of a variable displacement swash plate compressor. To provide a control valve.

[0005]

According to a first aspect of the present invention, there is provided a control valve for use in a variable displacement compressor capable of changing a discharge capacity by controlling an internal pressure of a crank chamber. A passage chamber provided in the valve housing so as to be a part of a bleed passage connecting the suction chamber and the suction chamber; and a passage chamber provided in the passage chamber and divided into a crank chamber side area and a suction chamber side area. A valve seat formed with a valve hole communicating the two, a valve body disposed in a crank chamber side region of the passage chamber and capable of being separated from and connected to the valve seat, and a valve body disposed in a crank chamber side region of the passage chamber. A pressure-sensitive member which is displaceable in response to the pressure in the crank chamber, and which is operatively connected to the valve body, and which can be constantly biased in a direction to seat the valve body while elastically supporting the valve body. And the valve element when the valve element is seated on a valve seat. A seal area due, characterized in that the effective area of the pressure sensing member is configured to match or approximate.

According to this configuration, the valve opening of the control valve, that is, the arrangement of the valve element in the passage chamber is affected by at least the pressure-sensitive member that is sensitive to the internal pressure of the crank chamber (crank pressure Pc). The pressure-sensitive member biases the valve body in the direction of seating on the valve seat by the biasing force (referred to as f1) of the pressure-sensitive member, while the crank pressure Pc acting on the pressure-sensitive member causes the valve body to move away from the valve seat. Acts to displace the pressure sensitive member in the direction. The force is represented by Pc · A, where A is the effective area of the pressure-sensitive member. On the other hand, the valve body is pressed in the seating direction by the crank pressure Pc in the crank chamber side region, and is pressed in the direction to separate from the valve seat by the suction pressure Ps in the suction chamber side region. When the sealing area of the valve element when the valve element is seated on the valve seat is B, and the direction in which the valve element is seated on the valve seat is the positive direction, the force acting on the valve element can be summarized as f1-Pc · A.
+ Pc.B-Ps.B = 0, and when this is arranged,
f1 = Ps · B + Pc (A−B) In the present invention,
Since the sealing area B by the valve body and the effective area A of the pressure-sensitive member are set to be equal or approximate to each other, Pc of the above equation is obtained.
The (AB) term may be considered zero or negligibly small. Then, after all, the relational expression of the force acting on the valve element is f
1 = Ps · B, and this expression does not include Pc at all.
That is, according to this configuration, at first glance, it seems that the crank pressure Pc acts on the valve body, and in fact, the crank pressure Pc does not participate in the positioning of the valve body at all, and the force involved in the positioning of the valve body is not felt. The pressure member itself has only a force f1 for seating the valve body on the valve seat, and the suction pressure Ps is only a force (Ps · B) for separating the valve body from the valve seat. The arrangement of the valve element in the passage chamber is determined based on the balance between the two, and the opening of the control valve, that is, the opening (throttle amount) of the bleed passage is determined, and the crank pressure Pc is controlled. And from the above calculation result,
The suction pressure (set suction pressure) finally achieved by the valve opening adjustment operation of the control valve is Ps = f1 / B. As described above, according to the present invention, the effect of the crank pressure Pc can be almost eliminated from the dynamic relationship of determining the valve opening by making the sealing area B of the valve body and the effective area A of the pressure-sensitive member coincide or approximate. In addition, the autonomous valve opening adjustment operation corresponding to the change in the suction pressure Ps can be made more accurate than in the conventional example.

According to a second aspect of the present invention, in the control valve of the variable displacement compressor according to the first aspect, the pressure sensing member includes a first spring mechanism for urging the valve body in a direction of seating the valve body on a valve seat. In addition, a second spring mechanism for urging the valve body in a direction to separate the valve body from a valve seat is provided on the suction chamber side region side of the passage chamber, and the first spring mechanism and the second spring mechanism are provided. The valve body is elastically supported by a spring mechanism so as to be able to contact and separate from the valve seat.

According to this configuration, the valve body disposed in the crank chamber side region of the passage chamber is elastically supported so as to be able to contact and separate from the valve seat by cooperation of the first spring mechanism and the second spring mechanism. You. Therefore, even a slight change in the suction pressure Ps is sensed, and the arrangement of the valve body, that is, the valve opening can be quickly changed.

According to a third aspect of the present invention, in the control valve of the variable displacement compressor according to the first or second aspect, a rod having a distal end operatively connected to the valve body in a suction chamber side region of the passage chamber. And a solenoid portion capable of urging the rod in a direction separating the valve body from the valve seat with an electromagnetic urging force that can be adjusted by external electric control.

According to this configuration, when electromagnetic bias is performed by the solenoid portion, the force related to positioning of the valve body in the passage chamber is such that the above-described pressure-sensitive member attempts to seat the valve body on the valve seat. The force (f1), the force (Ps · B) that the suction pressure tries to separate the valve body from the valve seat, and the force (F) that the electromagnetic biasing force of the solenoid unit tries to separate the valve body from the valve seat. Be at least three. Therefore, the balance relationship of these three (f1 = Ps
(B + F), the arrangement of the valve body is determined, and the opening degree of the control valve and thus the opening degree (throttle amount) of the bleed passage are determined.
Since the electromagnetic urging force F can be adjusted by external electric control, the control valve according to claim 3 has a variable set suction pressure in which the set suction pressure Pset = (f1-F) / B can be changed by external control. Type control valve. If the set suction pressure variable valve is used, the capacity control of the compressor can flexibly respond to changes in the surrounding conditions.

According to a fourth aspect of the present invention, in the control valve for a variable displacement compressor according to the third aspect, the suction chamber of the compressor is provided in an area for accommodating an end of the rod opposite to a tip end thereof. , And the sealing area (B) of the valve element coincides with the effective area (A) of the pressure-sensitive member (see FIGS. 2, 3 and 4). ). According to a fifth aspect of the present invention, in the control valve of the variable displacement compressor according to the third aspect, a region for accommodating an end of the rod opposite to a tip end thereof is provided with a crank chamber of the compressor. The pressure (Pc) is guided, and the sealing area (B) of the valve element is the sum of the effective area (A) of the pressure-sensitive member and the effective pressure-receiving area (S) at the opposite end of the rod. The feature is that they match (see FIG. 5). Claims 4 and 5 limit the most preferable aspects of the present invention, and the technical significance will be clear in the description of “Embodiments of the invention” described later. Claim 5 shows an example of the approximation width in the sentence of “set so that the seal area by the valve element and the effective area of the pressure-sensitive member are approximated” in claim 1.

According to a sixth aspect of the present invention, in the control valve of the variable displacement compressor according to any one of the first to fifth aspects, the variable displacement compressor uses power of an external drive source for the compressor. And a clutch for selectively transmitting the clutch to the clutch. This clarifies that the control valve of the present invention is particularly suitable for a variable displacement compressor with a clutch.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a variable displacement type swash plate type compressor mounted on a vehicle according to an embodiment of the present invention.

(Outline of Compressor Body) As shown in FIG.
A front housing 2 is joined and fixed to a front end surface of a cylinder block 1 in which a plurality of cylinder bores 1a (only one is shown) are formed, and a crank chamber 3 is defined in the front housing 2. A rear housing 4 is joined and fixed to a rear end surface of the cylinder block 1 via a valve plate 5. The cylinder block 1, the front housing 2, the rear housing 4 and the valve plate 5 constitute a compressor housing. A suction plate 6 having a suction valve 6a and a discharge plate 7 having a discharge valve 7a are interposed in front of and behind the valve plate 5. The rear housing 4 includes a discharge chamber 9 located inside and a suction chamber 8 provided to surround the discharge chamber 9.
And are partitioned. Then, the suction chamber 8 and each cylinder bore 1a are formed through a suction hole 5a formed in the valve plate 5.
And a discharge hole 5b formed in the valve plate 5.
Each of the cylinder bores 1a and the discharge chamber 9 are communicated via the.

A rotary shaft 12 is rotatably supported on the cylinder block 1 and the front housing 2 by a pair of front and rear bearings 13. The outer end of the rotating shaft 12 is operatively connected to a vehicle engine E as an external drive source via an electromagnetic clutch 40. The electromagnetic clutch 40 is biased by a pulley 42 rotatably supported by a bearing 41 on a front cylindrical portion of the front housing 2, an annular solenoid coil 43, and a leaf spring 44 in the front end region of the rotating shaft 12. Armature 4 provided to be able to slide back and forth in the state
5 is provided. FIG. 1 shows a state in which the armature 45 is joined to the end face of the pulley 42 against the urging force of the leaf spring 44. When the armature 45 is attracted and joined to the end face of the pulley 42 by an electromagnetic force based on the energization of the solenoid coil 43, the power transmission belt 46, the pulley 4
The driving force of the engine E is transmitted to the rotating shaft 12 via the armature 2 and the armature 45. If the electromagnetic force disappears due to the stoppage of the current supply to the coil 43, the armature 45
The urging force of 4 separates the pulley 42 from the pulley 42 and cuts off power transmission. Thus, the engine power is selectively transmitted to the rotating shaft 12 by controlling the energization of the coil 43.

A rotating support 14 is fixed on the rotating shaft 12 in the crank chamber 3 so as to be integrally rotatable. A thrust bearing 15 is interposed between the rotating support 14 and the inner surface of the front housing 2. Further, a support arm 14a protruding toward the cylinder block 1 with respect to the outer peripheral side of the rotary support 14 has an elongated hole 14b.
Are formed, and the rotary swash plate 17 is connected via a connecting pin 16 constituting a hinge mechanism to be swingable in the front-rear direction. On the other hand, a sleeve 19 is provided on the rotating shaft 12 so as to be slidable in the front-rear direction. The sleeve 19 is connected to a boss 17a of the rotating swash plate 17 through a pair of left and right connecting pins 20 (only one is shown in FIG. It is connected to the inner periphery. A swinging swash plate 18 is provided on the outer peripheral side of the boss 17a of the rotating swash plate 17 so as to be relatively rotatable. The swing swash plate 18 is provided at a fixed position in the crank chamber 3 with a guide rod 21 for preventing rotation.
, So that it is not rotatable and tiltable in the front-rear direction. Further, the swinging swash plate 18 is connected to each piston 22 housed in each cylinder bore 1a via a piston rod 23. The rotation shaft 12 has a spring receiver 2.
4 is attached, and a spring 25 is interposed between the spring receiver 24 and the sleeve 19. The spring 25 is preferably a coil spring and urges the swash plates 17, 18 in a direction (leftward in FIG. 1) in which the inclination angle is maximum.

In the swash plate type compressor shown in FIG. 1, when the rotating shaft 12 is rotated by the transmission of power from the engine E, the rotating swash plate 17 inclined at a predetermined angle is rotated with the rotation. Performs a waving rocking motion. Then, each piston 22 is reciprocated at a stroke corresponding to the inclination angle of the swash plate, and in each cylinder bore 1a, the suction and compression of the refrigerant gas from the suction chamber 8 (area of the suction pressure Ps) and the discharge chamber 9 (the discharge pressure Pd) are performed. The discharge of the compressed refrigerant gas to the region is sequentially repeated.

Rotating swash plate 17 and swinging swash plate 18 of the compressor
Factors that determine the tilt angle of the swash plate (hereinafter referred to as a “swash plate”) include the moment of the rotational motion based on the centrifugal force when the swash plate rotates, the moment due to the spring force based on the urging action of the spring 25, and the reciprocating inertia of the piston There are various moments such as a moment due to a force and a moment due to a gas pressure. The inclination angle of the swash plate is determined based on the mutual balance of these moments. The moment due to the gas pressure refers to the mutual relation between the compression reaction force acting on the piston of the cylinder bore in the compression stroke, the internal pressure of the cylinder bore in the suction stroke, and the internal pressure of the crank chamber 3 (crank pressure Pc) corresponding to the piston back pressure. Is a moment generated based on the crank pressure P
Depending on c, it can act in both the inclination decreasing direction and the increasing direction.
In the present embodiment, by maintaining the crank pressure Pc large, the moment due to the gas pressure exceeds the moment in the direction of increasing the tilt angle due to the rotational motion and the spring force, and the swash plate is set to the minimum tilt angle (for example, a plane perpendicular to the rotation axis 12). The angle between the swash plate and the swash plate is set to 3 ° to 5 °). Further, the inclination of the swash plate is set to an arbitrary angle between the minimum inclination and the maximum inclination by reducing the crank pressure Pc and balancing the moment due to the gas pressure and the moment due to the rotational movement and the spring force. You can do it. As described above, the inclination angle of the swash plate is determined based on the control of the crank pressure Pc, and the stroke of each piston 22, that is, the displacement of the compressor is variably adjusted according to the inclination angle.

The crank pressure P in the compressor shown in FIG.
The control configuration of c is such that passages 58, 59 provided in the compressor housing to connect the crank chamber 3 and the suction chamber 8 are provided.
And a withdrawal-side control valve 50 interposed in the passages 58 and 59. The control configuration of the crank pressure will be described later in detail.

The discharge chamber 9 and the suction chamber 8 of the compressor shown in FIGS. 1 and 2 are connected via an external refrigerant circuit 30.
The external refrigerant circuit 30 constitutes a cooling circuit of the vehicle air conditioning system together with the compressor. In the external refrigerant circuit 30,
A condenser (condenser) 31, a temperature-type expansion valve 32, and an evaporator (evaporator) 33 are provided. Expansion valve 3
The opening degree of the thermosensitive cylinder 3 provided on the outlet side of the evaporator 33 is
The feedback control is performed based on the detected temperature and the evaporation pressure in 2a, and the expansion valve 32 supplies the liquid refrigerant corresponding to the heat load to the evaporator 33. Thereby, the external refrigerant circuit 3 is controlled so that the evaporation state of the refrigerant in the evaporator 33 has an appropriate degree of superheat.
The refrigerant flow at zero is adjusted.

Further, as shown in FIG. 2, a temperature sensor 34 is provided near the evaporator 33. The temperature sensor 34 detects the temperature of the evaporator 33 and provides the evaporator temperature information to the control computer 38. The control computer 38 controls all controls related to cooling and heating of the vehicle air conditioning system. On the input side of the control computer 38, in addition to the temperature sensor 34, a room temperature sensor 35 for detecting the vehicle indoor temperature, a room temperature setting device 36 for setting the vehicle indoor temperature, an air conditioning system operation switch 37, and the engine E
Electronic control unit (ECU) is connected. On the other hand, a drive circuit 39A for controlling the energization of the solenoid coil 43 of the electromagnetic clutch 40 and a drive circuit 39B for controlling the energization of the coil 77 of the control valve 50 described later are connected to the output side of the control computer 38. Have been. The control computer 38 controls the evaporator temperature obtained from the temperature sensor 34, the vehicle interior temperature obtained from the room temperature sensor 35, the desired room temperature set by the room temperature setting device 36, the ON / OFF setting status from the air conditioning system operation switch 37, and , EC
U controls the electromagnetic clutch 40 based on external information such as information on the start / stop of the engine E and the engine speed from U, and calculates an appropriate amount of current I to the coil 77 of the control valve 50. Then, the current having the calculated current value is supplied from the drive circuit 39B to the control valve 50, and the opening of the control valve 50 or the set suction pressure Pset is externally controlled.

(Structure of the withdrawal side control valve 50) Crank chamber 3
Pressure by adjusting the amount of refrigerant gas released from the
The configuration of the extraction side control valve 50 for controlling c will be described with reference to FIG. The gas supply to the crank chamber 3 in the swash plate type compressor shown in FIG. 1 is performed by blow-by gas (and / or a throttle (not shown)) leaking into the crank chamber 3 from between the piston 22 and the inner peripheral wall of the cylinder bore 1a in the compression stroke. Attached air supply passage).

The removal side control valve 50 is connected to the valve housing 5.
1 is provided with a valve mechanism section 52 provided therein and a solenoid section 70 joined to a lower side thereof. The valve housing 51 includes a main body 51a and a cap-shaped cover 51b provided thereon.
Inside, a valve chamber 53 is defined as a passage chamber. Valve housing body 51a that partitions valve chamber 53
An annular valve seat 54 is formed in the inner peripheral wall substantially at the center of the valve chamber 53 in the axial direction, and a valve hole 55 exists at the center of the valve seat 54. The valve chamber 53 is divided into an upper area (crank chamber side area) 53a and a lower area (suction chamber side area) 53b with the valve seat 54 as a boundary.

The valve housing 51 for partitioning the valve chamber 53
Are provided with an introduction port 56 formed in the upper region 53a of the valve chamber and an outlet port 57 formed in the lower region 53b of the valve chamber. Introduction port 56
Connects the upper region 53a of the valve chamber to the crank chamber 3 through a passage 58 provided in the compressor. Outgoing port 57
Communicates the lower region 53b of the valve chamber with the suction chamber 8 via a passage 59 provided in the compressor. Thus, between the crank chamber 3 and the suction chamber 8, the passage 58, the introduction port 56,
A bleed passage including the valve chamber 53, the outlet port 57, and the passage 59 is set.

The valve body 60 is accommodated in the upper region 53a of the valve chamber so as to be movable in the vertical direction (the axial direction of the control valve), and the valve body 60 can be moved toward and away from the valve seat 54 in accordance with the movement. Has become. When the valve body 60 is seated on the valve seat portion 54, the valve hole 55 is closed by the valve body 60, and the communication between the upper region 53a and the lower region 53b is cut off. The valve body 60 is provided with an engaging projection 60 protruding above the valve body 60 as shown in FIG.
a and a recess 60b that opens downward. Further, a bellows 61 as a pressure-sensitive member is provided in the upper region 53a of the valve chamber. The upper end of the bellows 61 is fixed to a recess formed at the top of the valve housing cover 51b, and the upper end of the bellows 61 is a fixed end and the lower end is a movable end. The bellows 61 is evacuated or decompressed, and the bellows 61 has an extension spring 6.
2 are provided. This extension spring 62 is a bellows 61
Is urged downward (extending direction). At the movable end of the bellows 61, a concave portion opened to the lower side is formed,
In the recess, the ball 63 and the engagement protrusion 60 of the valve element 60 are provided.
a is engaged. Therefore, the movable end of the bellows 61 and the valve body 60 have a relationship of mutually transmitting forces. Therefore, the bellows 61 is under atmospheric pressure (in this case, the crank pressure P
c) can be expanded and contracted (that is, displaced) in response to (c), and is operatively connected to the valve body 60 to elastically support the valve body 60. Further, the bellows 61 containing the extension spring 62
0 is always urged in the direction of sitting on the valve seat 54. In addition,
The effective area A of the bellows 61 as a pressure sensing member, and the diameter area B of the valve hole 55 (or the lower region 53b of the valve chamber) (ie, the sealing area by the valve when the valve 60 is seated on the valve seat 54). B) (A = B).

The solenoid 70 occupying the lower half of the control valve 50 has a cylindrical housing cylinder 71 with a bottom. A fixed iron core 72 is fitted to the upper part of the housing cylinder 71, and a solenoid chamber 73 is defined in the housing cylinder 71 by this fitting. A movable iron core 74 as a plunger is accommodated in the solenoid chamber 73 so as to be movable in the vertical direction. The movable iron core 74 has a support pin 74a at the center thereof, and both are integrated. At the center of the fixed iron core 72, a solenoid rod 75 as a transmission member is supported movably in the vertical direction. One end (upper end) of the solenoid rod 75 enters the lower region 53b of the valve chamber and is engaged in the engagement recess 60b of the valve body 60. On the other hand, the other end (lower end) of the solenoid rod 75 is disposed in the solenoid chamber 73 and is in contact with the upper surface of the movable iron core 74. Therefore, the movable end of the bellows 61, the valve body 60, the solenoid rod 75, and the movable iron core 74 are in a relationship of mutually transmitting an axial force. Note that a small gap CL is secured between the outer peripheral surface of the solenoid rod 75 disposed in the control valve and the inner peripheral surfaces of the valve housing 51 and the fixed iron core 72 which are in sliding contact with the solenoid rod 75. . The lower area 53b of the valve chamber communicates with the solenoid chamber 73 through the gap CL. That is, the suction pressure Ps is applied to the solenoid chamber 73 as in the lower area 53b of the valve chamber (see FIG. 3).

As shown in FIG. 2, a biasing spring 76 is provided inside (or below) the movable core 74 around a support pin 74a.
Are arranged. This urging spring 76 is provided with a movable iron core 74.
And urges the solenoid rod 75 upward (that is, in the direction toward the valve body 60). Therefore, the valve body 60 is
The bellows 61 itself and the extension spring 62 through one movable end
And the upward biasing force from the biasing spring 76 via the movable iron core 74 and the rod 75, and the initial position in the valve chamber 53 is adjusted based on the balance of the upward and downward biasing forces. Has been determined. In other words, the bellows 61, the valve body 60, the solenoid rod 75, and the movable core 7
There is always a working connection between the four. In addition, a coil 77 is provided around the fixed iron core 72 and the movable iron core 74 in a range over the iron cores 72 and 74. A predetermined current is supplied to the coil 77 from a drive circuit 39B based on a command from the control computer 38.
The coil 77 generates an electromagnetic force having a magnitude corresponding to the supply current amount I. The movable core 74 is attracted to the fixed core 72 by the electromagnetic force, and the solenoid rod 75 moves upward, and the valve body 60 is urged upward with the upward movement.

The degree of opening of the extraction side control valve 50, that is, the degree of opening of the bleed passage, is determined by various spring members 62, 76 constituting the control valve 50,
It is determined by the balance between the extension urging force of the bellows 61 affected by the crank pressure Pc and the electromagnetic urging force of the solenoid unit 70, and the electromagnetic urging force is electrically variably adjusted from the outside to set the suction of the control valve 50. The pressure Pset can be changed as appropriate, and the operating characteristics of the control valve can be changed according to the situation. In the control valve 50, a first spring mechanism that biases the valve body 60 in a direction in which the valve body 60 is seated on the valve seat 54 by the bellows 61 and the extension spring 62 is configured.
4. A second spring mechanism for urging the valve body 60 away from the valve seat 54 by the rod 75 and the urging spring 76 is configured, and the valve body 60 can be brought into and out of contact with the valve seat 54 by both spring mechanisms. An elastic support mechanism for elastically supporting the elastic member is formed.

(Operation Regarding Compressor Capacity Control) When the air-conditioning system operation switch 37 is turned off, the electromagnetic clutch 40 is in a disconnected state, power is not supplied from the engine E to the compressor, and the compressor stops operating. Also, the control valve 50
No current is supplied to the coil 77. When the operation of the compressor is stopped for a long time, the pressures in the chambers 3, 8, and 9 of the compressor are equalized, and the swash plate is maintained at the initial angle.

When the air conditioner system operation switch 37 is ON while the engine E is being driven, the control computer 38 energizes the solenoid coil 43 of the electromagnetic clutch to connect the engine E and the compressor to operate the compressor. Along with
The coil 77 of the control valve 50 is energized. The amount of current I to the coil 77 is calculated in advance in the air-conditioning control program based on the temperature difference between the detected room temperature of the room temperature sensor 35 and the set temperature of the room temperature setting device 36, the evaporator temperature information from the temperature sensor 34, and the like. It is calculated according to the method. Then, an electromagnetic attractive force corresponding to the amount of current I is generated between the two cores 72 and 74,
Accordingly, the upward electromagnetic urging force F of the solenoid rod 75 is determined. As a result, the control valve 50 is adjusted to a valve opening corresponding to the electromagnetic urging force F, and the crank pressure Pc and the suction pressure Ps are determined accordingly. This will be described below.

(Tilt control of the swash plate based on control of crank pressure Pc): When the control valve 50 is opened by energizing the coil 77, the crank chamber 3 is moved from the crank chamber 3 to the suction chamber 8 via a bleed passage.
Gas is released to If the amount of gas released through the bleed passage is greater than the amount of gas supplied to the crank chamber 3 by blow-by gas or the like due to a large valve opening, the crank pressure Pc tends to decrease (swash plate tilt angle). Is increasing). On the other hand, if the amount of gas supplied to the crank chamber 3 by blow-by gas or the like is greater than the amount of gas released through the bleed passage due to the small valve opening, the crank pressure Pc tends to increase (inclined). The plate inclination angle is decreasing.) As a result of such autonomous valve opening adjustment, when the amount of gas supplied to the crank chamber 3 and the amount of gas discharged through the bleed passage are balanced, the crank pressure Pc is made constant, and the swash plate is set at an angle corresponding to the crank pressure Pc. The tilt is adjusted.

(Suction pressure P not affected by crank pressure Pc
Setting of s): This point will be described with reference to FIG. FIG.
Is a simplified schematic representation of the mechanical relationship of the control valve internal mechanism. In FIG. 3, the movable end of the bellows 61 and the valve body 60 are depicted as being connected by a thin wire, but this is a kind of equivalent expression, and based on this equivalent diagram, the valve body 60 and the bellows 61 of FIG. The conclusion is the same even if the effect of the crank pressure Pc acting on is considered. In FIG.
The downward urging force of the entire bellows including the bellows 61 and the extension spring 62 is f1, and the upward urging force of the urging spring 76 is f.
2. The electromagnetic attraction force (upward urging force of the solenoid rod 75) of the movable iron core 74 when the coil 77 is energized is denoted by F. As described above, the effective area of the bellows 61 is A,
The bore area of the lower region 53b of the valve chamber (that is, the sealing area by the valve body 60) is B. Also, the solenoid rod 75
Let S be the cross-sectional area perpendicular to the axis of the rod, and consider that the influence of the suction pressure Ps acting on the entire surface of the rod 75 and the movable iron core 74 is concentrated on the lower end surface of the rod. The effective pressure receiving area of the movable iron core 74 with respect to the suction pressure Ps matches the cross-sectional area S of the rod 75 orthogonal to the axis. Then, the suction pressure Ps acting on the lower end of the rod is
The solenoid rod 75 is urged upward by a force equivalent to (Ps · S).

Then, the urging force in the valve opening direction (upward) received by the valve body 60 from the solenoid portion 70 is (F + f2 + P
s · S). Further, the urging force in the valve closing direction (downward) received by the valve body 60 from the bellows 61 is (f1-Pc · A).
It is. Further, the valve closing direction (downward) is on the upper surface side of the valve body 60.
A force Pc (B−S) acts in the valve opening direction (upward) on the lower surface side of the valve body 60. The following relationship expressed by the following equation 1 is established between these forces. Note that the term including the effective pressure receiving area S is clearly eliminated in the process of rearranging the equation (1).

[0034]

(Equation 1)

[0035]

(Equation 2) In this embodiment, A = B, so if this area condition is substituted into Equation 2, the Pc (BA) term becomes zero,
The suction pressure Ps is expressed by the following equation (3).

[0036]

(Equation 3) In Equation 3, f1, f2, and B (= A) can be regarded as predetermined constant values in the mechanical configuration, and the electromagnetic urging force F is a function of the amount of current I to the coil 77. Therefore, the suction pressure Ps finally realized as a result of the valve opening degree adjustment operation of the control valve 50, that is, the set suction pressure, can be variably set by the energization amount I to the coil 77, and the physical amount independent of the crank pressure Pc Become. As can be seen from this equation, in the control valve 50, when energization of the coil 77 is stopped, F =
0, the suction pressure Ps becomes maximum, and the suction pressure Ps tends to decrease as the amount of current supplied to the coil 77 increases.

As described above, the control computer 38 calculates the amount of current I to the coil 77 based on various types of input information and externally controls the opening of the control valve 50, thereby adjusting the swash plate inclination angle and adjusting the compressor inclination. And the internal pressure of the suction chamber 8 (suction pressure Ps) substantially equal to the outlet pressure Ps' of the evaporator 33 is maintained near a desired pressure value (ie, the set suction pressure Pset). Becomes possible. The purpose of the compressor control by the control valve 50 and the control computer 38 is irrespective of the fluctuation of the cooling load in the evaporator 33.
The discharge capacity of the compressor is variably adjusted so that the outlet pressure Ps ′ of the evaporator 33 reflecting the cooling load is stabilized near the set suction pressure Pset. In this sense, the solenoid 70 of the control valve 50 and the control computer 38 determine the suction pressure Ps
Is externally controlled as a means for controlling the valve opening so that the set suction pressure Pset is obtained. Also, the set suction pressure Pse
Since t can be changed only by controlling the coil current I by the control computer 38, the solenoid unit 70 of the control valve 50 and the control computer 38 are also means for externally changing the set suction pressure Pset of the control valve 50.

During the operation of the compressor, when the cooling load becomes very small and the temperature of the evaporator 33 approaches the frost generation temperature, the control computer 38 stops the energization of the coil 77 and moves the solenoid rod 75 upward. The power F disappears (F = 0). In this way, the control valve opening tends to be closed by maximizing the set suction pressure Pset, and the crank pressure Pc is increased to guide the swash plate angle to a minimum, thereby minimizing the discharge capacity of the compressor and avoiding the occurrence of frost. I do.

(Effects) According to the present embodiment, the following effects can be obtained. By making the effective area A of the bellows 61 equal to the bore area B of the valve hole 55 (that is, the sealing area B of the valve body 60) in the control valve 50, the suction is performed according to the control of the amount of electricity I to the coil 77. The pressure Ps is changed to the crank pressure Pc (Pc
Can be accurately determined without depending on Pd). Therefore, according to the control valve 50, the set suction pressure Pset can be set more accurately than before.

The desired set suction pressure Pset (that is, the outlet pressure Ps' of the evaporator 33) is set within the range of the suction pressure Ps corresponding to the range of the amount of current I actually controllable (from zero to the maximum value).
(Desired value) can be easily included, and as a result, the variable width of the set suction pressure Pset in the control valve 50 can be ensured in a practically large range.

(Another Example) The embodiment of the present invention may be modified as follows.で は In the configuration of FIG. 2, a connection structure that prevents eccentricity of force transmission by interposing a ball 63 between the movable end of the bellows 61 and the valve body 60 is adopted, but a simpler structure as shown in FIG. 4 is used. A connection structure may be employed. That is, in FIG. 4, the movable end of the bellows 61 is integrated with the valve body 60 as it is. In this case, most of the upper surface side of the valve body 60 is the bellows 6.
1 is covered by the lower end portion of FIG. 1, but the structure of FIG. 4 and the structure of FIG. 2 are equivalent with respect to the influence of the crank pressure Pc. FIG.
The effective pressure receiving area in which the upper half of the valve body 60 is exposed to the influence of the crank pressure Pc is the area (B) obtained by subtracting the effective area A of the bellows covering and covering the upper surface of the valve body from the seal area B.
-A). On the other hand, the area where the lower half of the valve body 60 is exposed to the influence of the suction pressure Ps is (BS). Taking this point into account and formulating the same as above, the following equation 4 is obtained.

[0042]

(Equation 4) Equation (4) is the same as Equation (1). By rearranging Equation (4), the same equation as Equation (2) is obtained, and if the condition of A = B is applied, the result is exactly the same as Equation (3). . Therefore, the structure of FIG. 4 is equivalent to the structure of FIG. 2, and the structure of FIG. 4 can also be represented by the equivalent diagram of FIG. From this result, according to the present invention, as long as the movable end of the bellows 60 as the pressure-sensitive member and the valve body 60 maintain a relation in which they can move synchronously, the thickness or diameter of the connecting portion between the two can be set. This does not change the essence of the invention.

As shown in FIG. 5, the crank pressure Pc may be introduced into the solenoid chamber 73 in which the lower end of the solenoid rod 75 is housed, instead of the suction pressure Ps. Of course, in that case, the lower region 53b of the valve chamber and the solenoid chamber 7
3 must be ensured. FIG.
In the control valve according to the configuration of the above, a dynamic relational expression as shown in the following Expression 5 is established, and by rearranging it, Expression 6 is obtained.

[0044]

(Equation 5)

[0045]

(Equation 6) In the control valve of FIG. 5, if the sealing area B by the valve body 60 is
When it is set to be equal to the sum of the effective area A of the bellows 61 and the effective pressure receiving area S at the lower end of the solenoid rod 75, P in the equation (6) is obtained from the area condition of B = A + S.
The term c (B−A−S) becomes zero, and (B−S) = A
Becomes By substituting these into Equation 6 and rearranging, the following Equation 7 is obtained.

[0046]

(Equation 7) In Equation 7, f1, f2, and A can be regarded as predetermined constant values on the mechanical configuration, and the electromagnetic biasing force F is a function of the amount of current I to the coil 77. Number 3
It has the same physical meaning as an expression. Therefore, the control valve according to the configuration of FIG. 5 also functions as a variable suction pressure control valve that does not depend on the crank pressure Pc, and has the same operation and effect as the control valve shown in FIGS. 2 and 3.

In the above-described embodiment and other examples, the bellows 61 is used as the pressure-sensitive member, but a diaphragm may be used instead. The term “swash plate type compressor” as used in this specification includes not only a wobble type compressor as shown in FIG. 1 but also a compressor having a swash plate as a swash plate. It means all compressors that reciprocate the piston by the plate.

(Points of the technical idea other than the matters described in the claims) (a) In claim 2, the first spring mechanism is constituted by a bellows 61 and an extension spring 62, and the second spring mechanism is The plunger 74, the solenoid rod 75, and the urging spring 76 are used. The first and second spring mechanisms constitute an elastic support mechanism that elastically supports the valve body so as to be able to contact and separate from the valve seat in the passage chamber. (B) Claims 1 to 6
, Wherein the pressure-sensitive member is a bellows. The bellows has a large degree of freedom of expansion and contraction displacement, and is extremely suitable as a pressure-sensitive member which acts on the valve element in response to the crank pressure Pc in the passage chamber. (C) In the first to sixth aspects, the sealing area by the valve body is equal to the diameter area of the suction chamber side area of the passage chamber.

[0049]

As described in detail above, according to the control valve described in each claim, the set suction pressure can be accurately set without being affected by the pressure (Pc) of the crank chamber of the variable displacement compressor. It is possible to do.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a variable displacement swash plate type compressor according to one embodiment.

FIG. 2 is a vertical sectional view of a control valve on the extraction side.

FIG. 3 is an equivalent diagram of a dynamic relationship of the control valve of FIG. 2;

FIG. 4 is an essential part cross-sectional view showing another example of the connection structure between the pressure-sensitive member and the valve body.

FIG. 5 is an equivalent view of a dynamic relationship of another control valve.

[Explanation of symbols]

3 ... Crank chamber, 8 ... Suction chamber, 9 ... Discharge chamber, 17 ... Rotating swash plate, 18 ... Swinging swash plate (17 and 18 constitute a swash plate), 40 ... Clutch, 50 ... Control valve, 51 ... Valve housing, 53: valve chamber (passage chamber), 53a: upper area of valve chamber (crank chamber side area), 53b: lower area of valve chamber (suction chamber side area), 54: valve seat (valve seat), 55 ... valve hole, 56, 57 ... introduction port, outlet port, 58, 59
... passages (53, 56, 57, 58, 59 constitute bleed passages), 60 ... valve bodies, 61 ... bellows (pressure-sensitive members),
62: an extension spring (61 and 62 constitute a first spring mechanism); 70: a solenoid portion; 73: a solenoid chamber (a region for accommodating the end opposite to the tip of the rod); 74: a movable core (plunger) ), 75: solenoid rod (rod), 76: biasing spring (74, 75, 76 constitutes a second spring mechanism), Pc: crank pressure, Ps: suction pressure.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Taku Yasiya 2-1-1 Toyotamachi, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation (72) Inventor Masaki Ota 2-1-1 Toyotamachi, Kariya-shi, Aichi Prefecture Shares F term in Toyota Industries Corporation (reference) 3H045 AA04 AA10 AA13 AA27 BA19 BA28 CA02 CA03 DA25 EA33 3H076 AA06 BB33 CC16 CC17 CC41 CC84 CC85 CC92 CC93

Claims (6)

[Claims] 1. A control valve for use in a variable displacement compressor capable of changing a discharge capacity by controlling an internal pressure of a crank chamber, a part of a bleed passage connecting a crank chamber and a suction chamber of the compressor. A passage chamber provided in the valve housing, and a valve hole provided in the passage chamber, which divides the passage chamber into a crank chamber side region and a suction chamber side region and communicates the two. A valve seat, a valve body disposed in the crank chamber side region of the passage chamber and detachable from the valve seat, and a valve body disposed in the crank chamber side region of the passage chamber and displaceable in response to a crank chamber pressure. And a pressure-sensitive member operably connected to the valve body and capable of constantly biasing the valve body in a direction of elastically supporting the valve body while seating the valve body on the valve seat. The sealing area of the valve body when seated on the Variable displacement compressor control valve, characterized in that the effective area and is configured to match or approximate the. 2. The pressure-sensitive member constitutes a first spring mechanism for urging the valve body in a direction in which the valve body is seated on a valve seat, and the valve body is provided on the suction chamber side region side of the passage chamber. A second spring mechanism is provided for urging the valve body away from the valve seat, and the valve body is elastically supported by the first spring mechanism and the second spring mechanism so as to be able to contact and separate from the valve seat. The control valve for a variable displacement compressor according to claim 1, wherein: 3. A valve having a distal end operatively connected to the valve body in a region of the passage chamber on the suction chamber side, and the valve body being moved from a valve seat by an electromagnetic biasing force adjustable by external electric control. The control valve for a variable displacement compressor according to claim 1 or 2, further comprising: a solenoid portion capable of urging the rod in a separating direction. 4. A pressure (Ps) of a suction chamber of the compressor is guided to a region for accommodating an end of the rod opposite to a tip end thereof, and a sealing area (B) of the valve body is 4. The control valve for a variable displacement compressor according to claim 3, wherein the control valve is equal to an effective area (A) of the pressure-sensitive member. 5. A pressure (P) pressure of a crank chamber of the compressor is provided in a region for accommodating an end portion of the rod opposite to a tip end portion thereof.
c) is derived and the sealing area by the valve element (B)
4 is equal to the sum of the effective area (A) of the pressure-sensitive member and the effective pressure-receiving area (S) at the opposite end of the rod. Control valve. 6. The variable displacement compressor according to claim 1, further comprising a clutch for selectively transmitting power of an external drive source to the compressor. A control valve for the variable displacement compressor according to claim 1.