JP2000009033A - Volume control valve for variable displacement compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a control mechanism which can vary intake pressure control characteristics without varying a sectional area of a seal of a valve body nor varying design conditions of bellows. SOLUTION: In a variable displacement compressor, a discharge chamber 57 is communicated with a crank chamber 61 by means of a first communication passage 71. A pressure chamber 17 is communicated with the crank chamber 61 by means of second communication passages 23, 24, 28. An extendable/contractable pressure sensing means 5 senses pressure inside an intake chamber 58 or the crank chamber 61. A transmitting rod 12 has one end abutting against the pressure sensing means 5. A valve element 15 is arranged in a valve chamber 16 for opening and closing the first communication passage 71 according to contraction/extention of the pressure sensing means 5. A spring 19 pressurizes one end of the valve element 15. A pressure sensing rod 21 is allowed to abut against the other end of the spring 19, and receives pressure in the discharge chamber 57 for adjusting a displacement rate of the spring 19. One end of the valve body 15 is projected into the pressure chamber 17. Pressure in the discharge chamber 57 and the crank chamber 61 is cancelled which is applied in opening and closing directions of the valve element 15, by adjusting pressure receiving areas of both ends of the valve element 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement control valve mechanism for a variable displacement compressor used in an air conditioner of an automobile.

[0002]

2. Description of the Related Art Conventionally, variable displacement compressors have been used in automobile air conditioners. FIG. 3 is a cross-sectional view showing an example of a schematic configuration of a conventional variable displacement compressor (see Japanese Patent Publication No. 4-74549). A variable displacement compressor 50 shown in FIG. 3 includes a cylinder block 51 having a plurality of concentrically arranged cylinder bores 51a, and a front housing 52 provided at one end of the cylinder block 51.
And a rear housing 53 provided at the other end of the cylinder block 51 with a valve plate device 54 interposed therebetween. The valve plate device 54 is provided in contact with the other end of the cylinder block 51.

In a rear housing 53, a valve plate device 54 is provided.
And the inner wall 55 and the outer wall 56, and the bottom wall 118,
The discharge chamber 57 and the suction chamber 58 are defined.

[0004] A crank chamber 61 is defined between one end of the front housing 52 and one end of the cylinder block 51, and a drive shaft 62 is disposed through the inside of the front housing 52. A swash plate mechanism 60 is provided around the drive shaft 62. Are located. The swash plate mechanism 60 includes a swing plate 63 that performs a swinging motion so as to be larger at the outer peripheral portion and gradually smaller at the outer periphery in a direction along the drive shaft 62, and a drive plate 64 that contacts the swing plate 63,
And a rotor 65 for driving the drive plate 64. The rotor 65 and the drive plate 64 are configured to be linked by a drive transmission member such as a guide pin 66. In addition,
Reference numerals 67a and 67b indicate thrust bearings, respectively.

The cylinder bore 51 of the cylinder block 51
a, a piston 68 is disposed so as to be slidable in the cylinder bore 51 along the center axis direction of the cylinder bore,
The piston 68 and the vicinity of one end of the swing plate 63 are connected by a piston rod 69 having spherical portions at both ends. In the bottom wall 118 at the other end of the rear housing 53, the capacity control valve mechanism 100 is disposed.

FIG. 4 shows a displacement control valve mechanism 10 according to the prior art.
FIG. 9 is a diagram showing an outline of a zero. In FIG. 4, the vertical relationship is opposite to that shown in FIG. Referring to FIG. 4, the displacement control valve mechanism 100 includes a casing body 1.
01, and a cap-shaped lid member 102 provided at one end of the casing main body 101. At the other end of the casing body 101, a valve chamber 10
3 is provided, and a pressure-sensitive space 104 for accommodating the pressure-sensitive means is formed between the lid member 102 and the concave portion at one end. A through-hole 105 is provided between the pressure-sensitive space 104 and the valve chamber 103 and communicates with each other in the longitudinal direction. On the other hand, the casing main body 101 extends in a direction orthogonal to the through-hole 105.
, Another through hole 106 is provided and communicates with the space 109 around the casing housing portion 101.

A valve body 107 is provided in the valve chamber 103, and the valve body 107 is urged downward in FIG. 4 by a spiral spring 108 toward one end of the through hole 105.

In the pressure-sensitive space 104, a pressure-sensitive member 1 is provided.
10 are provided. The pressure-sensitive member 110 is a support member 1
11, an adjusting screw portion 113, a bellows portion 112 provided therebetween, and an internal pressing spring 112 a provided inside the bellows portion 112. Through hole 10
5 is provided with a transmission rod 114, and a support member 111 is provided.
And the valve element 107. Adjustment screw part 113
Is the length direction of the bellows portion 112 (vertical direction in the figure)
Adjust the displacement position.

The conventional capacity control valve mechanism 1 having such a configuration.
In 00, the pressure-sensitive space 104 and the suction chamber 58
The communication is made via the communication hole 115. The valve chamber 10
3 communicates with a communication hole 116 that communicates with the discharge chamber 57 and a communication room 117 that follows the communication hole 116. Further, the through hole 106 communicates with the crank chamber 61 via the space and the communication passage 71.

The bellows portion 112 accommodated in the pressure-sensitive space 104 senses the pressure in the suction chamber 58, and in response to the pressure in the suction chamber 58, the valve 107 moves up and down, and the discharge chamber 57.
This is a so-called internal control type pressure control valve for adjusting the opening degree of the first passage from the first to the crank chamber 61.

In such a capacity adjusting valve mechanism, the force for pressing the valve element 107 composed of a ball valve in the valve closing direction is represented by F
The relationship between v and the force Fb acting on the bellows portion 112 and the transmission rod 114 to press the ball valve 107 in the valve opening direction is expressed by the following equations (1) and (2), respectively.

[0012]

(Equation 1)

[0013]

(Equation 2)

When Fv <Fb, the valve element 107 is opened. From the above equations (1) and (2), the following equation (3) is obtained.
The formula holds.

[0015]

(Equation 3) Here, when Pc = Ps + α and substituting and rearranging the above equation (3), the following equation (4) is established.

[0016]

(Equation 4)

The above equation (4) is the pressure control characteristic in the suction chamber of the displacement control valve mechanism. As shown in FIG. 5, the pressure in the suction chamber (hereinafter simply referred to as the discharge chamber pressure) depends on the pressure in the discharge chamber (hereinafter simply referred to as the discharge chamber pressure). , Simply referred to as suction chamber pressure).

[0018]

However, the pressure control characteristics of the suction chamber of the displacement control valve mechanism are set so as to obtain the optimum characteristics when the compressor is mounted on the vehicle. Since the optimum characteristics are different, a capacity control valve mechanism having pressure control characteristics of several kinds of suction chambers is required.

For example, as shown in FIG. 6, if the adjustment screws are used to adjust the displacement amounts fb ₁ , fb ₂ and fb ₃ of the spring 112a (see FIG. 4) inside the bellows portion 112, the characteristics can be improved. It can be moved up and down and changed.
There is also a method of optimizing characteristics by changing the amount of change in the pressure of the suction chamber 58 with respect to the pressure of the discharge chamber 57. In this case, in the conventional structure, it is necessary to change the sealing area of the valve element 107 composed of a ball valve or the effective area of the bellows 112.

However, a change in the effective area of the bellows portion 112 is not preferable in terms of design because it involves a significant change in the design of the capacity control valve mechanism 100, and also changes the sealing area of the valve element 107 composed of a ball valve. And the crankcase 61
The amount of discharge gas introduced into the chamber changes, and the crank chamber 61
There is a problem that the pressure rise characteristics change and the pressure control of the suction chamber 58 becomes unstable.

Therefore, a technical problem of the present invention is to provide a variable displacement valve capable of changing a suction pressure control characteristic by changing a change amount of a suction pressure with respect to a discharge pressure without changing a seal cross-sectional area of a valve body and design conditions on a bellows side. An object of the present invention is to provide a compressor capacity control mechanism.

[0022]

SUMMARY OF THE INVENTION In the present invention, attention is paid to the above-mentioned problem, and the amount of change in the pressure in the suction chamber with respect to the pressure in the discharge chamber is changed without changing the seal area of the valve body and the design conditions on the bellows side. It is configured to be able to change the chamber pressure control characteristic, and is provided in a variable displacement compressor including a discharge chamber, a suction chamber, and a crank chamber, and controls a piston stroke by adjusting a pressure in the crank chamber. A valve chamber communicating with the discharge chamber, a pressure chamber partitioned from the valve chamber, a first communication passage communicating the discharge chamber with the crank chamber, and A second communication path communicating between the chamber and the crank chamber, a pressure sensing means that expands and contracts by sensing the pressure in the suction chamber or the pressure in the crank chamber, one end of which abuts on the pressure sensing means,
A transmission rod supported so as to be able to be inserted so as to reach the valve chamber; and a transmission rod disposed in the valve chamber, abutting on the other end of the transmission rod, and the first communication path according to expansion and contraction of the pressure sensing means. A valve element that opens and closes, a valve guide portion that supports the valve element so that the valve element can be inserted, a spring that presses one end of the valve element, and a spring that abuts on the other end of the spring to act on the pressure of the discharge chamber. A pressure-sensitive rod for adjusting the displacement of the valve body, one end of the valve body,
While projecting into the pressure chamber, the pressure receiving area at one end of the valve body and the pressure receiving area at the other end of the valve body are adjusted to adjust the pressure in the discharge chamber acting in the opening and closing direction of the valve body and the pressure in the crank chamber. A displacement control valve mechanism for a variable displacement compressor characterized by eliminating a pressure force.

In the displacement control valve mechanism for a variable displacement compressor according to the present invention, the pressure receiving area of the transmission rod receiving the pressure in the crank chamber is equal to the pressure receiving area of the pressure sensing rod receiving the pressure in the crank chamber. It is characterized by having been set to.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. The variable displacement compressor provided with the displacement control valve mechanism according to the embodiment of the present invention is the same as that according to the prior art shown in FIG.

FIG. 1 is a sectional view showing a displacement control valve mechanism of a variable displacement compressor according to an embodiment of the present invention. With reference to FIG. 1, a capacity control valve mechanism 10 includes a casing body 1 provided at a central portion and provided with recesses at both ends, and a cap-shaped lid member 2 provided at one end of the casing body 1. It has a casing 3 and a pressure-sensitive part 5 disposed in a pressure-sensitive space 4 formed at one end of the valve casing 3. The pressure sensing portion 5 includes a support member 6 provided at one end and an adjustment screw member 8 provided at the other end, a bellows portion 7 disposed between the support member 6 and the adjustment screw member 8, and a bellows portion 7
And an internal spring 9 disposed inside the chamber that has been evacuated. The bellows 7 receives the pressure in the suction chamber 58. The adjusting screw member 8 adjusts the amount of displacement of the bellows portion 7.

The casing body 1 is provided with through holes 11 penetrating both ends in the axial direction. One end of the transmission rod 12 is supported in contact with one end of the support member 6 in the through hole 11. The other end of the transmission rod 12
It is in contact with one end of the valve body 15.

A valve guide 13 is provided at the upper end of the casing body 1 and further covers the outside thereof.
A cap 14 is provided. A cylindrical valve element 15 is inserted into the valve guide 13 so as to be vertically movable, and a valve chamber 16 is defined between the valve guide 13 and the upper end of the casing body 1. One end of the valve body 15 is provided with a large-diameter portion 15a, and the other end of the transmission rod 10 abuts.

Also, adjacent to the valve chamber 16, a valve guide 13 is provided.
And the cap 14, a pressure chamber 17 is defined. In the pressure chamber 17, a spring guide 18 and a spring 19 provided therebetween are provided. Spring guide 18
Has one end in contact with the other end of the valve body 15, and the other end of the spring guide 18 has in contact with one end of a pressure-sensitive rod 21 provided through the cap 14.

Therefore, the spring 19 is
, The valve body 15 is pressed in the valve closing direction.

The casing body 1 has one end merging with the upper end of the through-hole 11 and the casing body 1 obliquely downward.
, Through holes 23 and 24 are formed to reach the air chamber 22 whose other end is provided on the outer periphery. The air chamber 22 communicates with the crank chamber 61 via a communication passage 71. The valve chamber 16 communicates with a small space 26 provided on the outer periphery by a communication path 25 penetrating in the radial direction, and the small space 26 communicates with a discharge chamber 57 via a through hole 27. I have.

The through-hole 24 is provided with a communication passage 28 communicating with the pressure chamber 17. That is, the communication path 28 communicates the pressure chamber 17 with the outlet-side passage of the valve body 15, that is, the crank chamber 61.

The large diameter portion 15a of the valve body 15 is
The communication path between the discharge chamber 57 and the crank chamber 61 is opened and closed according to the expansion and contraction of the crankcase.

The pressure-sensitive rod 21 projecting into the space 26 receives the pressure of the discharge chamber 57 and adjusts the displacement of the spring 19.

The valve body 15 is inserted through the valve guide 13, and one end of the valve body 15 receives the pressure of the pressure chamber 17. Therefore, the crank chamber pressure acting on the contact surface of the valve body 15 with the valve seat 31 also acts on the upper surface of the valve body 15 in the drawing through the communication passage 28.

The pressure receiving area of the crank chamber pressure on the contact surface of the valve body 15 with the valve seat 31 and one end of the valve body 15 (the pressure chamber 16
Since the pressure receiving areas of the side (side) are set to be equal, the forces of the discharge chamber pressure and the crank chamber pressure acting in the opening and closing directions of the valve element 5 are offset.

Accordingly, the force Fv for pressing the valve body 15 in the valve closing direction and the force Fb acting on the bellows 7 and the transmission rod 12 to press the valve body 15 in the valve opening direction are expressed by the following equations (5) and (6), respectively. become that way.

[0037]

(Equation 5)

[0038]

(Equation 6)

When Fv <Fb, the valve body opens, but the following equation (7) is established from the above equations (5) and (6).

[0040]

(Equation 7) Here, if Pc = Ps + α, the following Expression 8 is established.

[0041]

(Equation 8) The above equation 8 is the suction pressure control characteristic of the displacement control valve mechanism according to the embodiment of the present invention.

Therefore, as shown in FIG. 2, even if the effective area (Sb) of the bellows and the area (Sv) of the valve body seal are not changed, the pressure receiving area (SK) of the pressure-sensitive rod 13 can be changed to change the discharge chamber pressure. Can be changed.

If Sr = Sk, the following equation (9) is obtained.

[0044]

(Equation 9)

The equation (9) is different from the equation (8) in that α is excluded, that is, the influence of the pressure in the crank chamber is eliminated. That is, by making the pressure receiving areas of the transmission rod 12 and the pressure sensing rod 21 equal, there is an effect that the control accuracy of the suction chamber pressure is further improved.

As shown by the characteristics of the flat portion in FIG. 2, when the discharge chamber pressure becomes lower than a predetermined value, the pressing force of the spring 19 becomes larger than the pressing force of the pressure-sensitive rod 21 due to the discharge chamber pressure. The other end of the guide 18 abuts on the cap 14 to obtain a suction chamber pressure control characteristic which is not affected by the pressure in the discharge chamber.

[0047]

As described above, according to the present invention,
It is possible to provide a displacement control mechanism of a variable displacement compressor capable of changing a suction pressure control characteristic by changing a change amount of a suction pressure with respect to a discharge pressure without changing a seal sectional area of a valve body and a design condition on a bellows side.

Further, according to the present invention, there is provided a displacement control mechanism for a variable displacement compressor capable of improving the control accuracy of the suction chamber pressure by making the pressure receiving areas of the transmission rod and the pressure sensing rod equal. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a displacement control valve mechanism according to an embodiment of the present invention.

FIG. 2 is a view showing a suction pressure control characteristic of the displacement control valve mechanism of FIG. 1;

FIG. 3 is a cross-sectional view illustrating an example of a schematic configuration of a variable displacement compressor according to the related art.

FIG. 4 is a cross-sectional view showing an outline of a capacity control valve mechanism 100 according to a conventional technique.

FIG. 5 is a view showing a suction pressure control characteristic of the displacement control valve mechanism of FIG. 4;

FIG. 6 is a diagram which is used for describing a method of changing the characteristic of the displacement control valve mechanism of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing main body 2 Lid member 3 Valve casing 4 Pressure sensitive space 5 Pressure sensitive part 10 Capacity control valve mechanism 11 Through hole 12 Transmission rod 13 Valve guide 14 Cap 15 Valve body 15a Large diameter part 16 Valve chamber 17 Pressure chamber 18 Spring guide 19 Spring 21 Pressure-sensitive rod 22 Air chamber 23, 24, 27 Through hole 25, 28 Communication path 26 Small space 31 Valve seat 50 Variable capacity compressor 51a Cylinder bore 51 Cylinder block 52 Front housing 53 Rear housing 53a Housing 54 Valve plate device 55 Inner wall 56 Outer wall 57 Discharge chamber 58 Suction chamber 60 Swash plate mechanism 61 Crank chamber 62 Drive shaft 63 Swing plate 64 Drive plate 65 Rotor 66 Guide pin 67a, 67b Thrust bearing 68 Piston 69 Piston rod 102 Cover member 105 Through hole 112 Bellows portion 114 Reaching rod 118 wall portion 100 capacity control valve mechanism 101 casing body 102 lid member 103 valve chamber portion 104 pressure sensitive space 105, 106 through hole 107 valve body 109 space 108 spiral spring 110 pressure sensitive member 111 support member 112 bellows portion 112a internal pressing Spring 113 Adjustment screw part 114 Transmission rod 116 Communication hole 117 Communication room

Claims (2)

[Claims] A displacement control valve mechanism provided in a variable displacement compressor having a discharge chamber, a suction chamber, and a crank chamber for controlling a piston stroke by adjusting a pressure of the crank chamber. A valve chamber communicating with the discharge chamber, a pressure chamber partitioned from the valve chamber, a first communication path communicating the discharge chamber with the crank chamber, and communicating the pressure chamber with the crank chamber. A second communication path;
A pressure sensing means that expands and contracts by sensing the pressure in the suction chamber or the pressure in the crank chamber, and a transmission rod that is supported so that it can be inserted so as to reach the valve chamber, with one end contacting the pressure sensing means. A valve body disposed in the valve chamber, abutting against the other end of the transmission rod, for opening and closing the first communication passage in accordance with expansion and contraction of the pressure sensing means, and a valve guide for supporting the valve body so that it can be inserted therethrough Part, a spring that presses one end of the valve body, and a pressure-sensitive rod that abuts the other end of the spring to adjust the amount of displacement of the spring by the pressure of the discharge chamber acting. One end protrudes into the pressure chamber, and adjusts the pressure receiving area at one end of the valve body and the pressure receiving area at the other end of the valve body, so that the pressure in the discharge chamber acting in the opening and closing direction of the valve body and the pressure The capacity of a variable displacement compressor characterized by eliminating the pressure force in the crank chamber Control valve mechanism. 2. The displacement control valve mechanism for a variable displacement compressor according to claim 1, wherein the pressure receiving area of the transmission rod receiving pressure in the crank chamber and the pressure receiving pressure of the pressure sensing rod receiving pressure in the crank chamber. A displacement control valve mechanism for a variable displacement compressor, wherein the area is set to be equal.