JP2000352380A - Method for controlling variable capacity compressor and control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control valve and method for controlling a variable capacity compressor capable of restraining hysteresis and improving responding performance and control accuracy. SOLUTION: This control method for controlling a variable capacity compressor for controlling opening/closing of a valve 3 (valve means) utilizes thrust by a pressure-sensitive portion 10 (pressure response means) responding to differential pressure between intake pressure Ps of coolant introduced into the compressor and reference pressure PoA and by a solenoid portion 2. The valve 3 (valve means) is used to obtain crank case pressure Pc for changing a tilt angle of a swash plate by adjusting discharge pressure Pd of a coolant output from the compressor. The reference pressure PoA is obtained by the pressure- adjusted coolant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method and a control valve for a variable displacement compressor, and more particularly to a technique for suppressing hysteresis and improving responsiveness and control accuracy.

[0002]

2. Description of the Related Art For example, there is a variable displacement compressor having a structure schematically shown in FIG. 14 used for an air conditioner of a vehicle (automobile). The compressor 300 oscillates with respect to a rotating shaft 301 to which a rotational driving force is input from a vehicle engine or the like, and converts the axial displacement of a swash plate 302 set to a predetermined inclination angle into a reciprocating motion of a piston 303. This is a swash plate type compressor that compresses the refrigerant.

In this compressor 300, the stroke of the piston 303 is determined in accordance with the inclination angle θ of the swash plate 302, and the amount of refrigerant discharged from the compressor 300 per rotation of the rotary shaft 301 is determined. When the inclination angle θ is fixed at a fixed value, the discharge amount (cooling capacity) of the refrigerant changes according to the change in the input rotation speed.

Accordingly, the inclination angle θ of the swash plate 302 is appropriately controlled in accordance with the rotation speed of the swash plate 302 and the required cooling capacity, and the reciprocating stroke of the piston 303 is changed to adjust the cooling capacity. Things are going on.

The inclination angle θ of the swash plate 302 of the compressor 300 is
As shown in FIG. 15, the discharge pressure Pd of the compressor 300,
It can be determined by the balance between the crankcase pressure Pc and the suction pressure Ps.

In adjusting the cooling capacity, for example,
The temperature at which the cold air blows through the evaporator having an endothermic effect due to the vaporization of the refrigerant (which also relates to the amount of the cool air blown out and the temperature before cooling) and the suction pressure P of the refrigerant into the compressor 300
Since s has a correlation, the suction pressure Ps increases as the cool air temperature increases, and the suction pressure Ps increases as the cool air temperature decreases.
s falls), and control is performed to adjust the discharge pressure Pd using the change in the suction pressure Ps to set the crankcase pressure Pc and set the swash plate 302 at a predetermined angle.

FIG. 16 is an explanatory view of a cross-sectional configuration of a conventional control valve 200 for performing such control. The control valve 200 includes a general solenoid unit 202, a valve unit 203, and a pressure sensing unit 21.
0.

The solenoid portion 202 is disposed at one end of a substantially cylindrical valve body 204 and is the same as that generally used according to a known technique, and supplies a current to the coil 202a. By generating a magnetic force and attracting the plunger 202b to the center post 202c, it is possible to generate an urging force (solenoid attraction force) having a magnitude corresponding to the current value.

The valve section 203 has a valve body 203b in a valve chamber 203a formed inside a valve body 204. The valve body 203b is configured to be movable in the axial direction in the valve chamber 203a so as to open and close a valve seat 203d opened in an isolation wall 203c provided in the valve chamber 203a.

The valve body 203b is urged in the valve opening direction by a spring 203e as an urging means, and is integrated with the solenoid side rod 202d. Valve part 2
The port 203f is connected to the valve chamber 203a of No. 03, and the port 203g is connected to the valve seat 203d on the opposite side of the valve chamber 203a.

The pressure-sensitive portion 210 receives the suction pressure Ps from the port 203h at one end and receives the pressure of the atmospheric pressure P0 and the biasing force of the spring 211 at the other end.
12, and transmits an axial force acting on the pressure-sensitive piston 212 to the valve body 203b via the connecting rod 213.

The atmospheric pressure P0 side is open, and the pressure-sensitive piston 212 is sealed by a seal member 214 in order to prevent leakage of the refrigerant accompanying the suction pressure Ps.

The port 203h guides the suction pressure Ps to the plunger chamber 202e through the communication passage 204a.

Therefore, such a control valve 200 in the prior art includes a pressure-sensitive piston 212 between the suction pressure Ps and the atmospheric pressure P0 for detecting the suction pressure Ps, and includes a pressure-sensitive piston 212 and springs 211 and 203e. The position of the valve 203b is controlled by the balance of the thrust F generated by the solenoid 202, the opening of the valve 203 is controlled, the crankcase pressure Pc is set, and the suction pressure Ps is consequently controlled. I was

FIG. 17 is a view for explaining the balance type of the control valve 200, where A is the pressure receiving area of the pressure sensitive piston 212,
B is the pressure receiving area of the connection rod 213, C is the pressure receiving area of the valve seat 203d, and D is the pressure receiving area of the solenoid side rod 202d. f0 is the urging force of the spring 211, f1 is the urging force of the spring 203e, and F is the thrust generated by the solenoid unit 202.

The balance equation is expressed as f0-PsA + PsB-PcB + PcC-PdC + f1 + PdD-PsD-F = 0.

In the above equation, if each pressure receiving area (corresponding to each port) is A = B = C = D, the following equation is obtained: Ps = (f0 + f1-F) / A

In the equation, by balancing each port diameter, the biasing force of the spring, and the thrust of the solenoid, a target control pressure characteristic shown in FIG. 18 can be obtained, for example.

Further, the aforementioned Pd, Pc,
Each port and the solenoid valve 200 which become the pressure of Ps
Are connected like the circuit shown in FIG.
The crankcase pressure Pc is connected to the suction pressure Ps via the orifice 305 inside the compressor 300, and if the operation of the compressor 300 is stopped (for example, when the engine is stopped), the pressure in the compressor becomes uniform. It has such a configuration.

[0020]

However, in the prior art control valve 200, the suction pressure Ps and the atmospheric pressure P0 are applied to both sides of the pressure sensing piston 212 for detecting the suction pressure Ps. A seal member 214 is required to prevent the refrigerant from leaking to the atmosphere, and the pressure-sensitive piston 212 loses slidability due to the binding force of the seal member 214. Hysteresis occurs in the control of the suction pressure Ps, resulting in a response. And improvement of control accuracy is desired.

An object of the present invention is to solve the above-mentioned problems of the prior art. An object of the present invention is to control a variable displacement compressor capable of suppressing hysteresis and improving responsiveness and control accuracy. It is to provide a method and a control valve.

[0022]

In order to achieve the above object, according to the present invention, the control of the discharge capacity of the refrigerant is changed according to the inclination angle of the rotating swash plate arranged in the crankcase, and the compression is controlled. A valve means for adjusting the discharge pressure of the refrigerant output from the compressor to obtain a crankcase pressure for changing the inclination angle of the swash plate, the difference between the suction pressure of the refrigerant input to the compressor and the reference pressure. A method of controlling a variable displacement compressor that controls the opening and closing of said valve means using a thrust by a pressure responsive means and a solenoid responsive to a differential pressure, wherein said reference pressure is obtained by said refrigerant whose pressure has been adjusted. It is characterized by.

By controlling the reference pressure with the regulated refrigerant as described above, the reference pressure and the suction pressure of the same refrigerant are applied to the pressure responsive means, and the refrigerants having produced both pressures are mixed. Alternatively, it is not necessary to use a sealing means for preventing the refrigerant from moving from the high pressure side to the low pressure side or a precise fitting fit. Therefore, the sliding resistance in the movement of the movable member such as the piston member of the pressure response means is suppressed, and the hysteresis can be suppressed, and the responsiveness and control accuracy can be improved.

Here, adjusting the reference pressure means adjusting the pressure to a predetermined pressure, and the predetermined pressure may be a constant pressure accompanied by minute fluctuations,
The predetermined pressure may be changed according to the control condition.

The reference pressure is a discharge pressure of the refrigerant,
It is also preferable that the pressure is regulated in the range of suction pressure ≦ reference pressure ≦ discharge pressure.

By setting the reference pressure in this manner, the discharge pressure can be adjusted and utilized, and the reference pressure can be easily obtained.

The control valve is a control valve used in a variable displacement compressor in which the displacement of the refrigerant is controlled by changing the inclination angle of a rotating swash plate disposed in a crankcase. Valve means for adjusting the discharge pressure of the refrigerant output from the compressor to obtain a crankcase pressure for changing the inclination angle of the swash plate; and a suction pressure of the refrigerant input to the compressor. A pressure responsive means that responds to a differential pressure between the pressure and the reference pressure, and a solenoid that can output a variable thrust, and performs opening / closing control of the valve means by using the thrust by the pressure responsive means and the solenoid. The reference pressure is obtained by the regulated refrigerant.

According to this control valve, the reference pressure and the suction pressure of the same refrigerant are applied to the pressure response means,
It is not necessary to use a sealing means or a precise fitting fitting for preventing the refrigerant having brought the two pressures from mixing or the refrigerant from moving from the high pressure side to the low pressure side. Therefore, the sliding resistance in the movement of the movable member such as the piston member of the pressure response means is suppressed, and the hysteresis can be suppressed, and the responsiveness and control accuracy can be improved.

It is also preferable that the pressure response means has a piston member which slides on the inner peripheral surface of the cylinder, and both ends of the piston member in the axial direction are pressure receiving portions for the suction pressure of the refrigerant and the reference pressure, respectively. is there.

It is also preferable to provide a pressure adjusting means for adjusting the pressure of the refrigerant to the reference pressure.

As the pressure adjusting means, for example, a pressure adjusting valve can be used. Further, the pressure adjusting means can be arranged to be attached to the compressor side or to the control valve, or can be arranged independently so that the reference pressure is transmitted to the control valve by a pressure transmission path. It is also possible to communicate.

The pressure adjusting means has a bellows which is constant at an internal pressure and expands and contracts by a pressure difference from an external pressure, and a valve means which is controlled to be opened and closed by the bellows, and controls the discharge pressure of the refrigerant output from the compressor. It is also preferable that the pressure is adjusted to a predetermined pressure and output as the reference pressure.

The pressure adjusting means includes a reference pressure chamber having a drain through which a refrigerant having a reference pressure is introduced and capable of discharging the refrigerant at a small flow rate, wherein the pressure of the reference pressure chamber is higher than a predetermined value. It is also preferable to provide a pressure valve for communicating the drain when the pressure becomes high.

Thus, it is possible to suppress the consumption flow rate of the refrigerant for generating the reference pressure.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIG. 1 is a view for explaining a sectional configuration of a solenoid valve 1 as a control valve according to a first embodiment of the present invention. This solenoid valve 1 is used for controlling the suction pressure Ps of a variable displacement compressor (similar to the compressor 300 described in the section of the prior art) used for an air conditioner of an automobile, for example.

The suction pressure Ps is controlled as a result by controlling the discharge pressure Pd of the variable displacement compressor and the crankcase pressure Pc by the valve unit 3 as valve means.

The solenoid valve 1 generally comprises a solenoid unit 2, a valve unit 3 as valve means, and a pressure sensing unit 10 as pressure response means.

The solenoid portion 2 is arranged at one end of a substantially cylindrical valve body 4 and is the same as that generally used by a known technique, and supplies a current to the coil 2a. By generating a magnetic force and attracting the plunger 2b to the center post 2c, it is possible to generate an urging force (solenoid attraction force) having a magnitude corresponding to the current value.

The valve section 3 has a valve body 3b in a valve chamber 3a formed inside the valve body 4. The valve body 3b is configured to be movable in the axial direction in the valve chamber 3a so as to open and close a valve seat 3d opened in an isolation wall 3c provided in the valve chamber 3a.

The valve body 3b is urged in the valve opening direction by a spring 3e as an urging means, and is integrated with the solenoid side rod 2d. A port 3f is connected to the valve chamber 3a of the valve section 3, and a port 3g is connected to the valve seat 3d on the opposite side of the valve chamber 3a in the axial direction.

The pressure sensing section 10 utilizes a refrigerant used in the compressor. A piston member receiving the suction pressure Ps from the port 3h on one end side and receiving the reference pressure P0A generated inside the compressor or the reference pressure P0A and the urging force of the spring 11 by the pressure adjusting means described later on the other end side. A pressure-sensitive piston 12 is provided.

The axial force acting on the pressure-sensitive piston 12 is transmitted to the valve 3b via the connecting rod 13. The connecting rod 13 is urged by a spring 14 in a direction to close the valve body 3b.

The other end of the pressure-sensitive piston 12, that is, the pressure receiving portion 12a at the reference pressure P0A, has a reference pressure chamber 15 for accommodating and holding a predetermined amount of refrigerant (reference pressure P0A) by an end cap 16. Is formed. 15a is a reference pressure port.

In the pressure-sensitive piston 12, the valve body 4 serves as a cylinder housing, and the inner peripheral surface 4b of the cylinder has a small clearance (although it is a clearance seal, it is important to exert good sliding characteristics. Is allowed), the movement with less sliding resistance and hysteresis is possible.

The port 3h guides the suction pressure Ps to the plunger chamber 2e through the communication passage 4a.

Therefore, the solenoid valve 1 applies a suction pressure Ps (suction pressure Ps) of the same refrigerant to the pressure-sensitive piston 12 from the plunger chamber 2e side through the communication passage 4a to detect the suction pressure Ps. The pressure-sensitive piston 12 is provided between the suction pressure Ps applied to the pressure side and the reference pressure P0A, and the pressure-sensitive piston 12, the springs 11, 14, and 3e, the thrust F generated by the solenoid unit 2, and the like are provided. The position of the valve body 3b is controlled by the balance, the valve opening control of the valve section 3 is performed, the crankcase pressure Pc is set, and as a result, the suction pressure Ps is controlled.

In this case, the reference pressure P0A is adjusted in the range of suction pressure Ps ≦ reference pressure P0A ≦ discharge pressure Pd (for example, 0.5 [MPa] ≦ reference pressure P0A ≦ 0.6 [MPa]). As a result, the discharge pressure Pd can be regulated and used, and the reference pressure P0A can be easily obtained.

Here, adjusting the reference pressure means adjusting the pressure to a predetermined pressure. The predetermined pressure may be a constant pressure accompanied by a slight fluctuation,
The predetermined pressure may be changed according to the control condition.

FIG. 2 is a view for explaining the balance type of the solenoid valve 1. A is the pressure receiving area of the pressure sensing piston 12, B is the pressure receiving area of the connecting rod 13, C is the pressure receiving area of the valve seat 3d, and D is the pressure receiving area of the valve seat 3d. This is the pressure receiving area of the solenoid side rod 2d. f0 is the urging force of the spring 11, f1 is the urging force of the spring 14, f2 is the urging force of the spring 3e, and F is the thrust generated by the solenoid unit 2.

The balance equation is as follows: f0 + P0AA-PsA + PsB-f1-PcB + PcC-PdC + f2 + PdD-PsD-F = 0

In the above equation, if each pressure receiving area (corresponding to each port) is A = B = C = D, the following equation is obtained: Ps = P0A- (F + f1-f0-f2) / A

In the equation, the target control pressure characteristic can be obtained by balancing each port diameter, the biasing force of the spring, and the thrust of the solenoid.

The relationship between the solenoid valve 1 and the compressor (the same as the compressor 300 in the prior art) is connected as shown in the circuit of FIG. The crankcase pressure Pc is connected to the suction pressure Ps via the orifice 305 inside the compressor 300,
If the operation stop state is continued (for example, when the engine is stopped), the pressure in the compressor becomes uniform.

Next, an embodiment of the reference pressure valve 20 as a pressure adjusting means for generating the reference pressure P0A will be described with reference to FIG. Since the reference pressure P0A is desirably formed in a closed container (suppressing leakage of the refrigerant), in this embodiment, the bellows assembly 21 whose inside is sealed with a vacuum or a constant pressure is used.

The reference pressure valve 20 regulates the discharge pressure Pd so as to be equal to the reference pressure P0A.
2, a reference pressure chamber 23 having a reference pressure P0A, and valve means 24.

The bellows assembly 21 is disposed in the reference pressure chamber 23 and has a bellows core 21a whose inside is sealed in a vacuum state or a constant pressure, stoppers 21b, holders 21c, and bellows cores 21a which hold both ends of the bellows core 21a. A spring 21d is provided to extend the inside of the member and apply a biasing force, thereby preventing collapse.

Then, it expands and contracts in response to the pressure (reference pressure P0A) around the bellows core 21a, and extends to a predetermined length or more via a bellows-side rod 21e slidably held by a holder 21c. In case (reference pressure P0A
When the pressure drops, the valve body 24a is separated from the seat portion 24b and opened, and the discharge pressure Pd is introduced into the reference pressure chamber 23 to recover the reference pressure P0A.

The end of the valve body 24a opposite to the bellows assembly 21 is applied with the reference pressure P0A by the communication passage 25 and urged by the spring 26 in the valve closing direction.

FIG. 5 is a view for explaining the balance type of the reference pressure valve 20, where S is the pressure receiving area of the bellows assembly 21,
1 is a pressure receiving area of the seat portion 24b, and B1 is a pressure receiving area of the valve body 24a. f0 is the biasing force of the spring 21d, f1
Is the urging force of the spring 26.

The balance equation is as follows: When the interior of the bellows assembly 21 is evacuated, -P0AS + f0 + P0AA1-PdA1 + PdB1-P0AB1-f1 = 0 In the above equation, each pressure receiving area (corresponding to each port) is represented by A = B. Then, P0A = (f0−f1) / S
It becomes an expression.

FIG. 6 is a diagram showing a block configuration of a pressure control section of the compressor when the reference pressure valve 20 is used. The reference pressure P0A generated by the reference pressure valve 20 is applied to the reference pressure chamber 2.
3 is introduced to the reference pressure port 15a of the solenoid valve 1 from the port 23a. At this time, the reference pressure chamber 2
By discharging a fixed amount (small amount) of the reference pressure P0A from the pressure chamber 3 (or the reference pressure chamber 15) to the suction pressure Ps side (in FIG.
Discharge to the side), it is possible to further stabilize the reference pressure P0A.

The arrangement of the solenoid valve 1 and the reference pressure valve 20 may be separate or integrated, or the reference pressure valve 20 may be provided on the compressor side.

(Embodiment 2) As in the case of the reference pressure valve 20 in the first embodiment, when the reference pressure P0A is drained at a small flow rate, the discharge pressure Pd is indirectly changed to the suction pressure Ps. Since it is discharged, there is a concern that the efficiency of the compressor may be reduced.

Therefore, the second embodiment detects the reference pressure P0A of the reference pressure valve 30 with the object of minimizing the discharge from the reference pressure P0A to the suction pressure Ps and stabilizing the reference pressure P0A. Only when the reference pressure P0A becomes higher than a predetermined pressure, the reference pressure P0A
Is discharged to the suction pressure Ps.

FIG. 7 is an explanatory view of the cross-sectional structure of the reference pressure valve 30. The same components as those of the reference pressure valve 20 are denoted by the same reference numerals, and description thereof will be omitted.

As a characteristic configuration of the reference pressure valve 30, a discharge pressure chamber 31 connected to a communication passage 25 used as a drain at a portion of the housing 22 opposite to the bellows assembly 21.
Is formed.

The bellows assembly 32 is provided inside the exhaust pressure chamber 31.
Is provided. The bellows assembly 32 controls the valve body 33 to be separated from the seat portion 34 and discharged to the discharge chamber 31 only when the reference pressure P0A input through the communication passage 25 becomes higher than a predetermined pressure. I do.

The refrigerant discharged to the discharge pressure chamber 31 is discharged from the discharge pressure port 35 to the suction pressure Ps side.

FIG. 8 is a view for explaining the balance type of the reference pressure valve 30. S1 denotes the pressure receiving area of the bellows assembly 21,
A2 is a pressure receiving area of the seat portion 24b, B2 is a pressure receiving area of the valve body 24a, and C2 is a pressure receiving area of the seat portion 34. f0
Is the urging force of the spring 21d, f1 is the urging force of the spring 26, and f2 is the urging force of the spring 32d (provided inside the bellows assembly).

In this reference pressure valve 30, the control from the discharge pressure Pd to the reference pressure P0A and the control from the reference pressure P0A to the suction pressure Ps are independent.
→ The reference pressure P0A, the reference pressure P0A → the suction pressure Ps are different. When the interior of each bellows assembly is evacuated, discharge pressure Pd → reference pressure P0A side: −P0AS1 + f0 + P0AA2-PdA2 + PdB2-P0AB2 = 0 In the equation, each pressure receiving area (corresponding to each port) is
Assuming that A2 = B2, P0A = (f0−f1) / S1.

Reference pressure P0A → Suction pressure Ps side: P0AC2-PsC2-f2 + PsS2 = 0 In the equation, each pressure receiving area (corresponding to each port) is
If S2 = C2, P0A = f2 / S2 (10)

Only when the reference pressure P0A becomes higher than a predetermined pressure, the consumption of the discharge pressure Pd can be suppressed by discharging the reference pressure P0A to the suction pressure Ps.

Although the reference pressure valve 30 employs a configuration in which the two bellows assemblies 21 and 32 are integrally provided in the housing 22, there is no problem if they are independently configured as separate components. Further, although the description has been made using the bellows assembly as the pressure adjusting means, a diaphragm can be used, and the same operation and effect can be obtained.

(Embodiment 3) FIG. 10 is an explanatory sectional view of a solenoid valve 51 according to a third embodiment.
The feature of this embodiment is that the solenoid valve 1 and the reference pressure valve 20 described in the separate embodiment are integrally formed in one solenoid valve 51 in the first embodiment.

The solenoid valve 51 includes a solenoid portion 52, a valve portion 53 serving as valve means, a pressure sensitive portion 60 serving as pressure response means, and a reference pressure valve 70 serving as pressure adjusting means for generating a reference pressure P0A. I have.

The solenoid 52 is disposed at one end of a substantially cylindrical valve body 54 and is similar to a generally used one according to a known technique, and supplies a current to the coil 52a. Generating magnetic force, plunger 5
By attracting 2b to the center post 52c, it is possible to generate an urging force (solenoid attraction force) having a magnitude corresponding to the current value.

The valve section 53 has a valve body 53b in a valve chamber 53a formed inside the valve body 54. The valve element 53b is configured to be movable in the axial direction in the valve chamber 53a so as to open and close a valve seat 53d opened in the side wall surface portion 53c of the valve chamber 53a.

The valve body 53b is urged in the valve opening direction by a spring 53e as urging means, and is in contact with the solenoid rod 52d. Valve chamber 5 of valve section 53
A port 53f is connected to 3a, and a valve chamber 53 of a valve seat 53d is provided.
Port 53g is connected to the side opposite to the axis a in the axial direction. The port 53f becomes the crankcase pressure Pc, and the port 5f
The discharge pressure Pd is introduced into 3 g.

The pressure-sensitive section 60 is provided with a pressure-sensitive piston 62 connected to the valve body 53b, and a suction pressure chamber 65 into which refrigerant used for the compressor, which has a suction pressure Ps, is introduced. The suction pressure Ps is introduced from the suction pressure chamber 65 to the plunger chamber 52e via the communication passage 66.

The bellows assembly 71 having the same structure as that described in the first embodiment is provided in the suction pressure chamber 65.
The reference pressure valve 70 utilizing the valve body 54 is disposed.
72 abutting on seat portion 54a formed at the end of the valve body 72
Open / close control.

A reference pressure chamber 73 is provided between the seat portion 54a and the pressure-sensitive piston 62 so as to hold a predetermined volume of refrigerant. The reference pressure chamber 73 has a discharge pressure Pd transmitted through a gap between the sliding portions of the pressure-sensitive piston 62 by the reference pressure valve 70.
Is set to the regulated reference pressure P0A.

In this case, the reference pressure P0A is adjusted in a range of suction pressure Ps ≦ reference pressure P0A ≦ discharge pressure Pd (for example, 0.5 [MPa] ≦ reference pressure P0A ≦ 0.6 [MPa]). As a result, the discharge pressure Pd can be regulated and used, and the reference pressure P0A can be easily obtained.

In order to stabilize the reference pressure P0A, it is preferable that the capacity of the reference pressure chamber 73 is large. If necessary, the dimensions of the reference pressure chamber 73 can be increased in the axial direction and the radial direction. is there.

FIG. 11 is a view for explaining the balance type of the solenoid valve 51. S3 is the pressure receiving area of the bellows assembly 71, S4 is the pressure receiving area of the seat portion 54a, A3 is the pressure receiving area of the pressure sensing rod 62, B3 Is the pressure receiving area of the valve seat 53d, C3 is the pressure receiving area of the solenoid side rod 52d, f0
Is the biasing force of the spring inside the bellows assembly 71, f1
Is the urging force of the spring 53e, and F is the thrust of the solenoid.

On the reference pressure generation side, f0−PsS3 + PsS4−P0AS4 = 0 (11) In the equation (11), if S3 = S4, the following equation is obtained: P0A = f0 / S3 (12).

On the crankcase pressure Pc generation side, PoAA3-PdA3 + PdB3-PcB3 + f1 + PcC3-PsC3-F = 0 (13) Equation (13) If each pressure receiving area is A3 = B3 = C3, then Ps = P0A- (F −f1) / A (14), and the target can be controlled.

Accordingly, by integrating the solenoid valve and the reference pressure valve into one solenoid valve 51, the same pressure is applied to the pressure-sensitive piston 62 by the same refrigerant, and a seal member for preventing the refrigerant from leaking to the atmosphere is provided. This is unnecessary, and it is possible to eliminate hysteresis due to the binding force of the seal member.

(Embodiment 4) FIG. 12 is an explanatory sectional view of a solenoid valve 51R according to a fourth embodiment. 12, the same components as those of the solenoid valve 51 are denoted by the same reference numerals.

In the solenoid valve 51 of the third embodiment, the communication passage 66
Although the suction pressure Ps is introduced into the plunger chamber 52e through the opening, the communication passage 66 is not provided in this embodiment, and the suction pressure Ps is introduced into the plunger chamber 52e from the gap between the center post 52c and the solenoid side rod 52d. The introduced crankcase pressure Pc is introduced.

The other structure is the same as that of the solenoid valve 51.

FIG. 13 is a view for explaining the balance type of the solenoid valve 51R.
S4 is the pressure receiving area of the seat portion 54a, A3 is the pressure receiving area of the pressure sensing rod 62, B3 is the pressure receiving area of the valve seat 53d, f0 is the biasing force of the spring inside the bellows assembly 71, and f1 is the force of the spring 53e. The urging force, F, is the thrust of the solenoid.

On the reference pressure (P0A) generation side (FIG. 13)
(Refer to (a)), f0−PsS3 + PsS4−P0AS4 = 0 (15) When the reference pressure P0A is transformed with the left side from the equation (15), P0A = (f0−Ps (S3 + S4)) / S3 (16), and the bellows is obtained. By setting the pressure receiving area S3 of the assembly 71 and the pressure receiving area S4 of the seat portion 54a, the reference pressure P0A is set.
Can be set according to the change in the suction pressure Ps.
The pressure supply to the reference pressure chamber 73 uses a leak from the discharge pressure Pd (due to a gap between the valve body 54, the pressure-sensitive piston 62, and the sliding portion).

On the crankcase pressure Pc generation side (FIG. 1)
3 (b)), PoAA3-Pd (A3-B3) -PcB3 + f1-F = 0 Equation (17) In Equation (17), the relationship between the pressure receiving area A3 of the pressure-sensitive rod 62 and the pressure receiving area B3 of the valve seat 53d is expressed by the following equation. If A3 = B3, P0A = Pc + (F-f1) / A3 (18)

By substituting equation (16) into equation (18), Ps = (S4 (f1-PcA3-F) + A4f0) / (A4 (S3-S4)) (19)

When Ps = Pc when the valve is closed,
The expression (19) is as follows: Ps = (S4 (f1-F) / (A4S3) + f0 / S3 (20)

From the equation (20), it is possible to obtain a target control pressure characteristic by balancing each pressure receiving area, spring set load, and solenoid thrust.

Therefore, the reference pressure P0A is regulated so as to change in accordance with the change in the suction pressure Ps, and the pressure of the same refrigerant is applied to the pressure-sensitive piston 62, so that a seal member for preventing the refrigerant from leaking to the atmosphere is not required, and the seal is not required. Hysteresis due to the binding force of the member can be eliminated.

At this time, the reference pressure P0A is the suction pressure Ps ≦
Reference pressure P0A ≦ discharge pressure Pd, for example, 0.1
It is desirable to adjust the pressure so as to vary within a range of (MPa) ≦ reference pressure P0A ≦ 1 (MPa).

[0099]

According to the present invention described above, it is possible to control the variable displacement compressor while suppressing the hysteresis and increasing the responsiveness and control accuracy.

When the reference pressure is controlled by the regulated refrigerant, the reference pressure and suction pressure of the same refrigerant are applied to the pressure response means of the control valve, and the refrigerant which has produced both pressures is mixed. Alternatively, it is not necessary to use a sealing means for preventing the refrigerant from moving from the high pressure side to the low pressure side or a precise fitting fit. Therefore, the sliding resistance in the movement of the movable member such as the piston member of the pressure response means is suppressed, and the hysteresis can be suppressed, and the responsiveness and control accuracy can be improved.

By adjusting the reference pressure in the range of suction pressure ≦ reference pressure ≦ discharge pressure, the discharge pressure can be adjusted and utilized, and the reference pressure can be easily obtained.

By providing a pressure valve for communicating the drain when the pressure in the reference pressure chamber of the pressure adjusting means becomes higher than a predetermined value, it is possible to suppress the consumption flow rate of the refrigerant for generating the reference pressure. Becomes

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a cross-sectional configuration of a solenoid valve according to an embodiment.

FIG. 2 is a diagram illustrating a balanced state of a solenoid valve.

FIG. 3 is a circuit diagram showing a relationship between a solenoid valve and a compressor.

FIG. 4 is an explanatory diagram of a cross-sectional configuration of a pressure adjusting unit.

FIG. 5 is a diagram illustrating a balance state of a pressure adjusting unit.

FIG. 6 is a block diagram of a pressure control unit when a pressure adjusting unit is used.

FIG. 7 is an explanatory diagram of a cross-sectional configuration of a pressure adjusting unit.

FIG. 8 is a diagram illustrating a balance state of a pressure adjusting unit.

FIG. 9 is a block diagram of a pressure control unit when a pressure adjusting unit is used.

FIG. 10 is an explanatory sectional view of a configuration of a solenoid valve.

FIG. 11 is a diagram illustrating a balanced state of a solenoid valve.

FIG. 12 is an explanatory diagram of a cross-sectional configuration of a solenoid valve.

FIG. 13 is a diagram illustrating a balance type of a solenoid valve.

FIG. 14 is a diagram schematically illustrating a configuration of a compressor.

FIG. 15 is a diagram illustrating a relationship between pressures applied to a compressor.

FIG. 16 is an explanatory sectional view of a solenoid valve according to the prior art.

FIG. 17 is a view for explaining a balanced state of a solenoid valve according to the conventional art.

FIG. 18 is a view showing a target control pressure characteristic.

FIG. 19 is a circuit diagram showing a pressure path of the compressor.

[Explanation of symbols]

 Reference Signs List 1 solenoid valve (control valve) 2 solenoid part 2a coil 2b plunger 2c center post 2d solenoid side rod 2e plunger chamber 3 valve part (valve means) 3a valve chamber 3b valve body 3c isolation wall 3d valve seat 3e spring 3f, 3g, 3h Port 4 Valve body 4a Communication passage 4b Cylinder inner peripheral surface 10 Pressure sensitive part (pressure response means) 11 Spring 12 Pressure sensitive piston 13 Connecting rod 14 Spring 15 Reference pressure chamber 15a Reference pressure port 16 End cap 20 Reference pressure valve (pressure adjusting means 21) Bellows assembly 22 Housing 23 Reference pressure chamber 24 Valve means 25 Communication passage 26 Spring Ps Suction pressure Pd Discharge pressure Pc Crankcase pressure P0A Reference pressure

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Nishinozono 4-3-1 Tsujido Shinmachi, Fujisawa City, Kanagawa Prefecture Inside NOK Co., Ltd. (72) Inventor Takaki Watanabe 4-3-3 Tsujido Shinmachi, Fujisawa City, Kanagawa Prefecture No. 1 F-term in NOK Co., Ltd. (Reference) 3H045 AA04 AA10 AA13 AA27 BA19 BA28 CA01 CA02 CA03 CA29 DA25 EA33 3H056 AA01 BB01 CD06 EE06 GG01 GG11 GG13 3H106 DA05 DA23 DB02 DB12 DB22 DB32 DC08 DD09 EE04KK06

Claims (7)

[Claims] The control of the discharge capacity of the refrigerant is changed according to the inclination angle of a rotating swash plate disposed in a crankcase, and the discharge pressure of the refrigerant output from a compressor is regulated to adjust the inclination of the swash plate. For valve means for obtaining a crankcase pressure for changing the angle, pressure control means for responding to a differential pressure between a suction pressure of refrigerant inputted to the compressor and a reference pressure and thrust generated by a solenoid are used. A method of controlling a variable displacement compressor for controlling the opening and closing of a means, wherein the reference pressure is obtained from the regulated refrigerant. 2. The variable displacement compression according to claim 1, wherein the reference pressure is obtained by regulating the discharge pressure of the refrigerant in a range of suction pressure ≦ reference pressure ≦ discharge pressure. Machine control method. 3. A control valve for use in a variable displacement compressor in which a displacement of a refrigerant is controlled by changing a tilt angle of a rotating swash plate disposed in a crankcase, wherein the compressor is provided. A valve means for adjusting the discharge pressure of the refrigerant output from the compressor to obtain a crankcase pressure for changing the inclination angle of the swash plate; and A pressure responsive means responsive to a differential pressure; and a solenoid capable of outputting a variable thrust. A control valve obtained by using the pressurized refrigerant. 4. The pressure response means has a piston member that slides on the inner peripheral surface of the cylinder, and both ends of the piston member in the axial direction are pressure receiving portions for the suction pressure of the refrigerant and the reference pressure, respectively. The control valve according to claim 3, characterized in that: 5. The control valve according to claim 3, further comprising pressure adjusting means for adjusting the pressure of the refrigerant to the reference pressure. 6. The pressure adjusting means has a bellows that is constant at an internal pressure and expands and contracts by a differential pressure from an external pressure, and a valve means that is controlled to open and close by the bellows, and discharges refrigerant output from a compressor. The control valve according to claim 5, wherein the pressure is adjusted to a predetermined pressure and output as a reference pressure. 7. The pressure adjusting means includes a reference pressure chamber having a drain through which a refrigerant having a reference pressure is introduced and capable of discharging the refrigerant at a very small flow rate, wherein a pressure of the reference pressure chamber is a predetermined value. The control valve according to claim 5, further comprising a pressure valve that allows the drain to communicate when the pressure becomes higher.