KR20040042801A - A control valve for variable displacement compressor - Google Patents

Abstract

PURPOSE: A control valve for a variable displacement compressor is provided to reduce leakage of refrigerant gas in a completely closed state. CONSTITUTION: A control valve(CV) is installed in an air supply passage(7) for controlling opening of the air supply passage to decide an inner pressure of a crank chamber(5), thereby controlling discharge capacity of a compressor(1). In the control valve, a bearing surface(32a) of a valve seat(32) and an opening/closing face(31a) of a valve element part(31) for adjusting the opening of the air supply passage are made of high-hardness materials. Accordingly, the bearing surface of the valve seat and the opening/closing face of the valve element part are prevented from being scratched by collision of alien substances included in refrigerant gas.

Description

Control valve for variable displacement compressor {A CONTROL VALVE FOR VARIABLE DISPLACEMENT COMPRESSOR}

The present invention relates to a control valve for controlling the discharge capacity of the variable displacement compressor constituting the refrigeration cycle.

The variable displacement swash plate type compressor (hereinafter referred to as a compressor) used in the refrigeration cycle has a configuration in which the inclination angle of the swash plate, that is, the discharge capacity, can be changed by adjusting the internal pressure of the crank chamber, which is the swash plate storage chamber (for example, Japanese Patent Laid-Open Patent Application). Publication 2001-173556 (p. 15-16, FIG. 12).

That is, the compressor is provided with a control valve for adjusting the internal pressure of the crank chamber. The control valve changes, for example, the opening degree of the air supply passage connecting the high pressure region of the refrigeration cycle and the crank chamber. The low pressure region of the refrigeration cycle and the crankcase are communicated through the bleed passage.

And, by adjusting the opening degree of the control valve, while controlling the balance of the amount of introduction of the high-pressure refrigerant gas into the crank chamber in the high pressure region through the supply passage and the amount of gas extraction from the crank chamber to the low pressure region through the bleeding passage is controlled The internal pressure is determined. As a result of the change in the inclination angle of the swash plate according to the change in the internal pressure of the crank chamber, the stroke of the piston, that is, the discharge capacity of the compressor is adjusted.

However, it is generally made to use carbon dioxide instead of the conventional freon as a refrigerant of a refrigeration cycle in recent years. When carbon dioxide is used as the refrigerant, the difference between the high pressure and the low pressure of the refrigeration cycle is much larger than that with the freon refrigerant (eg 10 MPa). Therefore, in the above configuration in which the discharge capacity of the compressor is adjusted by using the pressure difference in the refrigeration cycle, the refrigerant gas may flow at a high speed through the inside of the control valve in accordance with the large high and low pressure difference generated in the refrigeration cycle.

When the refrigerant gas flows through the inside of the control valve at a high speed, the erosion of the inside of the control valve is caused by minute substances (for example, solid particles of 10 to 20 µm) contained in the refrigerant gas, which are not completely removed by the filter. Occurs. Due to the control valve structure, erosion is likely to occur in the vicinity of the valve opening degree adjustment position, which causes the flow line of the refrigerant gas to be large and complicatedly bent. In particular, if a flaw occurs in the seat surface of the valve seat and the opening / closing surface of the valve body constituting the valve opening degree adjusting position, the entire closed state of the control valve, in other words, the state in which the seat surface of the valve seat is in contact with the opening / closing surface of the valve body. In addition, there is a problem in that the refrigerant gas leaks through the scratches, so that the discharge capacity of the compressor cannot be maintained according to the entire closed state of the control valve.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control valve of a variable displacement compressor capable of reducing refrigerant gas leakage in a full occluded state.

FIG. 1 (a) is a schematic view of a variable displacement swash plate type compressor and a sectional view of a control valve, and FIG. 1 (b) is an enlarged view near the valve opening adjustment position in FIG. 1 (a).

* Explanation of symbols on the main parts of the drawing

1: Variable displacement swash plate compressor as variable displacement compressor

2: suction chamber as low pressure region of refrigeration cycle

4: Oil Separator as High Pressure Zone

5: crankcase

6: additional passage connecting crank chamber and suction chamber

7: Air supply passage connecting crankcase and oil separator

31: valve body portion as valve body

31a: opening and closing surface of the valve body

32: valve seat

32a: seat surface of the valve seat

CV: control valve

Means to solve the problem

In order to achieve the above object, in the control valve of the first aspect of the invention, at least one of the seat surface of the valve seat for adjusting the opening degree of the passage and the opening / closing surface of the valve body is made of a material of high hardness. Therefore, even when the foreign matter (solid particles) contained in the refrigerant gas collides, scratches hardly occur on at least one of the seat surface of the valve seat and the open / close surface of the valve body. Therefore, it is possible to reduce the leakage of the refrigerant gas in the entire closed state of the control valve resulting from this scratch, and to maintain the discharge capacity of the variable displacement compressor according to the total closed state of the control valve.

In addition, the said "high hardness material" means the material of hardness which is hard to produce erosion in consideration of the magnitude | size of the high-low pressure difference in the refrigeration cycle, the material, the magnitude | size, etc. of a foreign material.

2. The invention according to claim 1, wherein both the seat surface of the valve seat and the open / close surface of the valve body are made of a material of high hardness. Therefore, even when the foreign matter (solid particles) contained in the refrigerant gas collides, scratches are hardly generated on the seat surface of the valve seat made of a material of high hardness and on the opening / closing surface of the valve body. Thus, leakage of refrigerant gas in the totally closed state of the control valve can be more effectively reduced.

In addition, the seat surface and the opening and closing surface is made of a different material. Therefore, it can prevent that a so-called "metal-metal phenomenon" arises between these both surfaces.

Claim 3 Invention of Claim 1 or 2 refers to the "high hardness material" which is especially preferable to apply to the control valve of a variable displacement compressor for refrigerant | coolant compression. That is, the material of the high hardness is nickel plating, nickel-phosphorus plating, nickel-boron plating, nickel-phosphorus-boron plating, nickel-boron-tungsten plating, chromium plating, copper plating, salt bath nitriding, ion nitriding, gas soft nitriding And surface hardening of a material (valve seat material and / or valve body material) by any one of carburization.

4. The invention according to any one of claims 1 to 3, wherein an oil separator for separating the lubricating oil from the refrigerant gas flowing through the region is arranged in the high pressure region of the refrigerating cycle. The passage also serves as a supply passage for supplying lubricating oil separated by the oil separator to the crank chamber by connecting the oil separator and the crank chamber.

In the oil separator, foreign matter is also separated from the lubricant oil from the refrigerant gas. Thus, for example, a large amount of foreign matter passes through the inside of the control valve as compared with the configuration in which the passage does not serve as a supply passage. However, at least one of the seat surface of the valve seat and the opening / closing surface of the valve body is made of a high hardness material, and even under such strict conditions, it is possible to reliably reduce the refrigerant gas leakage in the entire closed state of the control valve. . That is, the inventions of Claims 1 to 3 are particularly preferred for application in the case where the passage also serves as a supply passage for the lubricating oil from the oil separator to the crankcase.

In the invention, carbon dioxide is used as the refrigerant of the refrigerating cycle. Therefore, as described in the related art, the refrigerant gas may flow at a high speed through the inside of the control valve. However, at least one of the seat surface of the valve seat and the opening / closing surface of the valve body is made of a material of high hardness, and even under such severe conditions, it is possible to reliably reduce the refrigerant gas leakage in the entire closed state of the control valve. . That is, the inventions of Claims 1 to 4 are particularly preferred for application to control valves for handling carbon dioxide refrigerant.

Embodiment of the invention

Next, one Embodiment which actualized this invention is described.

In FIG. 1 (a), a variable displacement swash plate compressor (hereinafter, simply referred to as a compressor 1) constituting a refrigeration cycle of a vehicle air conditioner is schematically illustrated. The compressor 1 changes the volume of the compression chamber 1a in accordance with the rotation of a swash plate (not shown), so that the suction of the refrigerant gas from the suction chamber 2 to the compression chamber 1a, the compression of the suction refrigerant gas, and compression The discharge of the finished refrigerant gas from the compression chamber 1a to the discharge chamber 3 is performed. In the vicinity of the outlet of the discharge chamber 3, an oil separator 4 for separating lubricating oil contained in the mist gas in the refrigerant gas from the refrigerant gas is arranged. Moreover, carbon dioxide is used as a refrigerant | coolant of a refrigerating cycle.

In the compressor (1), the crank chamber (5), which is a swash plate storage chamber, and the suction chamber (2) as the low pressure region of the refrigeration cycle are connected via a bleed passage (6). The oil separator 4 and the crank chamber 5 as the high pressure region of the refrigerating cycle are connected via the air supply passage 7. In the oil separator 4, the lubricating oil separated from the refrigerant gas is supplied to the crank chamber 5 through the air supply passage 7 together with a part of the refrigerant gas and supplied to the lubrication of each sliding portion in the crank chamber 5. . In other words, the air supply passage 7 also serves as a supply passage for supplying the crank chamber 5 with lubricating oil separated by the oil separator 4.

Moreover, the filter 8 for removing a foreign material from refrigerant gas is arrange | positioned in the upstream (oil separator 4 side) of the said air supply path 7. The filter 8 is set to a mesh size capable of removing only foreign matters of 20 to 30 µm or more in terms of harmony so as not to impede the refrigerant gas flow.

In the middle of the air supply passage 7, a control valve CV capable of adjusting the opening degree of the passage 7 is arranged. Then, by adjusting the opening degree of the control valve CV, the amount of high-pressure refrigerant gas introduced into the crank chamber 5 from the discharge chamber 3 through the air supply passage 7 and the crank chamber 5 through the bleeding passage 6 are adjusted. ), The internal pressure of the crank chamber 5 is determined while the balance of the gas extraction amount into the suction chamber 2 is controlled. As a result of changing the inclination angle of the swash plate in accordance with the change in the internal pressure of the crank chamber 5, the discharge capacity of the compressor 1 is adjusted.

For example, when the opening degree of the said control valve CV becomes small and the pressure of the crank chamber 5 falls, the inclination angle of a swash plate will increase and the discharge capacity of the compressor 1 will increase. On the contrary, when the opening degree of the control valve CV increases and the internal pressure of the crank chamber 5 rises, the inclination angle of the swash plate decreases and the discharge capacity of the compressor 1 decreases.

Next, the control valve CV will be described in detail.

As shown in FIG. 1A, the valve housing 10 of the control valve CV includes a valve body 11 at the upper half and an actuator housing 12 at the lower half. In the valve body 11, the valve chamber 22, the communication path 23, and the decompression chamber 24 are divided in order from the lower side of the figure. In the valve chamber 22 and the communication path 23, the valve rod 25 is arrange | positioned so that the movement to the axial direction (up-down direction of drawing) of the valve housing 10 is possible. The communication path 23 and the pressure reduction chamber 24 are cut off at the upper end of the valve rod 25 inserted into the communication path 23.

The communication passage 23 communicates with the oil separator 4 of the compressor 1 through an upstream portion of the air supply passage 7. The valve chamber 22 communicates with the crank chamber 5 of the compressor 1 through the downstream of the air supply passage 7. The valve chamber 22 and the communication passage 23 constitute a part of the air supply passage 7.

As shown to FIG. 1 (a) and FIG. 1 (b), in the said valve chamber 22, the valve body part 31 as a valve body formed in the intermediate part of the valve rod 25 is arrange | positioned. In the valve body 11, the step located at the boundary between the valve chamber 22 and the communication path 23 forms the valve seat 32, and thus the communication path 23 forms the valve hole. Then, the valve rod 25 moves upward from the position shown in Fig. 1 (a), that is, from the open state of the communication passage 23 (the air supply passage 7) to the position where the valve body portion 31 is seated on the valve seat 32. On the lower surface, the planar opening / closing surface 31a of the valve body 31 and the planar seat surface 32a of the valve seat 32 come into contact with each other so that the communication passage 23 (the air supply passage 7) Is blocked. In the valve chamber 22, the rod elastic support spring 60 is arrange | positioned. The rod elastic support spring 60 elastically supports the valve rod 25 in the direction in which the valve body portion 31 is separated from the valve seat 32.

The bellows 33 is accommodated in the decompression chamber 24. The upper end of the bellows 33 is fixed to the valve housing 10. The upper end of the valve rod 25 is fitted to the lower end of the bellows 33. The inside of the decompression chamber 24 is partitioned by a bellows 33 having a bottomed cylindrical shape into a first pressure chamber 49 which is an inner space of the bellows 33 and a second pressure chamber 50 which is an outer space. .

A fixed throttle 41 is disposed on the discharge passage 40 from the discharge chamber 3 to the external refrigerant circuit (not shown). The first pressure chamber 49 is connected to the discharge passage 40 on the upstream side (discharge chamber 3 side) than the fixed throttle 41 via the first pressure passage 42. The second pressure chamber 50 is connected to the discharge passage 40 on the downstream side of the fixed throttle 41 via the second pressure detecting passage 43. Therefore, the bellows 33 is displaced at the lower end in accordance with the pressure difference before and after the fixed throttle 41, so that the change in the pressure difference is reflected in the positioning of the valve rod 25 (valve body part 31). Moreover, the bellows 33 operates the valve body part 31 so that the discharge capacity of the compressor 1 may be changed in the direction which removes the fluctuation of the pressure difference before and behind the fixed throttle 41.

The electromagnetic actuator part 51 is formed in the lower side of the said valve housing 10. The electromagnetic actuator portion 51 is provided with a cylindrical housing cylinder 52 having a bottom in the center of the actuator housing 12. A cylindrical center post 53 is fitted into and fixed to the upper opening of the housing cylinder 52. The flanger chamber 54 is partitioned in the lowest part in the storage cylinder 52 by this center post 53 being fitted.

The flanger 56 is accommodated in the flanger chamber 54 so that the flanger 56 can move in the axial direction. A guide hole 57 extending in the axial direction is formed in the center of the center post 53, and the lower end side of the valve rod 25 is disposed in the guide hole 57 so as to be able to move in the axial direction. . The lower end of the valve rod 25 is fitted into the flanger chamber 54 to fix the flanger 56. Therefore, the flanger 56 and the valve rod 25 are always integrated and move up and down.

The coil 61 is wound around the center post 53 and the flanger 56 on the outer circumferential side of the housing 52. Electric power is supplied to this coil 61 according to the instruction | command of the air conditioner ECU which is not shown in figure. Therefore, an electromagnetic force (electron attraction force) of magnitude corresponding to the amount of power supplied to the coil 61 is generated between the flanger 56 and the center post 53, and the electromagnetic force is generated by the valve rod 25 (valve element) through the flanger 56. (31)).

In the control valve CV having the above configuration, the valve body portion 31 by the bellows 33 is changed by changing the electromagnetic force applied by the electromagnetic actuator portion 51 to the valve body portion 31 in accordance with the amount of power supplied from the outside. The control target (setting differential pressure) of the pressure difference before and after the fixed throttle 41 which becomes a reference | standard of the positioning operation | movement of can be changed. In other words, the control valve CV is configured to position the valve rod 25 (valve body portion 31) autonomously in accordance with the change in the pressure difference so as to maintain the set differential pressure determined according to the power supply amount to the coil 61. It is. The set differential pressure can be changed from the outside by adjusting the amount of power supplied to the coil 61.

In the present embodiment in which the discharge capacity of the compressor 1 is adjusted using the pressure difference in the refrigerating cycle as described in the prior art, the refrigerant gas is introduced into the air supply passage 7 according to the large high and low pressure difference generated in the refrigerating cycle. May flow at high speed. Therefore, inside the control valve CV which opens and closes the air supply passage 7, both the seat surface 32a of the valve seat 32 which is a valve opening degree adjustment position, and the opening / closing surface 31a of the valve body part 31 are opened. It is composed of high hardness material to prevent this erosion.

In addition, in this embodiment, "high hardness material" means that the difference in height of the refrigeration cycle may increase to about 10 MPa, and that the foreign matter which causes erosion is high hardness made of silicon oxide or the like and fine (10-20 µm). Since it is a solid particle, it refers to the material whose Vickers hardness is 500 or more.

The valve seat 32 is made of brass and has a Vickers hardness of about 200. Therefore, in order to make the seat surface 32a of the valve seat 32 into a high hardness material, the high hardness film 32b by nickel-phosphorus plating is formed in the surface of this valve seat 32 raw material. Thus, the seat surface 32a of the valve seat 32 is made of a high hardness material having a Vickers hardness of 500 to 800.

The valve rod 25 (valve body portion 31) is made of SUS and has a Vickers hardness of about 300. Therefore, in order to make the opening / closing surface 31a of the valve body part 31 into a high hardness material, the high hardness film 31b is formed in the surface of this valve body part 31 material by salt bath nitriding (tuftride). have. That is, the opening-closing surface 31a of the valve body part 31 is comprised from the high hardness material whose Vickers hardness is 900-1100.

In addition, the film thickness of each of the high hardness films 31b and 32b is about several micrometers to 1 mm, and the film thickness of each of the high hardness films 31b and 32b in FIG. 1B is enlarged for easy understanding. It is. In addition, illustration of the rod elastic support spring 60 is abbreviate | omitted in FIG.1 (b).

According to this embodiment, the following effects can be acquired.

(1) In the control valve CV, the seat surface 32a of the valve seat 32 and the opening / closing surface 31a of the valve body portion 31 are made of a high hardness material. Therefore, even if the foreign matter contained in the refrigerant gas collides, scratches hardly occur on the seat surface 32a of the valve seat 32 and the opening / closing surface 31a of the valve body portion 31. That is, the leakage of refrigerant gas in the entire closed state of the control valve CV caused by this scratch can be reduced, and the discharge capacity of the compressor 1 according to the total closed state of the control valve CV (this embodiment) In this case, the maximum discharge capacity can be maintained.

(2) The high hardness film 32b of the valve seat 32 and the high hardness film 31b of the valve body portion 31 are formed of different materials. Therefore, it is possible to prevent the occurrence of the metallurgical phenomenon between the seat surface 32a of the valve seat 32 and the open / close surface 31a of the valve body portion 31.

(3) The air supply passage 7 also serves as a supply passage for supplying the crank chamber 5 with lubricant oil separated by the oil separator 4. In the oil separator 4, foreign matter is also separated at the same time as lubricating oil separation from the refrigeration gas. Thus, for example, a large amount of foreign matter passes through the inside of the control valve CV as compared to the configuration in which the air supply passage 7 does not serve as a supply passage. However, in the control valve CV, the seat face 32a of the valve seat 32 and the open / close face 31a of the valve body portion 31 are made of a hard material, and even under such severe conditions, the control valve CV It is possible to reliably reduce the refrigerant gas leakage in the entire occluded state of the CV. That is, the embodiment of the present invention in the configuration in which the air supply passage 7 also serves as a supply passage for the lubricating oil from the oil separator 4 to the crank chamber 5 has the effect (in the totally closed state of the control valve CV). It is especially effective for achieving the refrigerant gas leakage reduction.

(4) The compressor 1 is a refrigerant compressor used in a refrigeration cycle, and carbon dioxide is used as the refrigerant in this refrigeration cycle. Thus, for example, the difference between the high and low pressures of the refrigerant in the control valve CV is much larger than that in the case of using the freon refrigerant, and the refrigerant flow rate is much higher, so that the seat surface 32a of the valve seat 32 and the valve body portion 31 Scratches caused by foreign substances are easily generated on the opening and closing surface 31a. That is, the embodiment of the present invention in the control valve of the carbon dioxide refrigerant compressor is particularly effective for exerting the effect (reduction of refrigerant gas leakage in the entire closed state of the control valve CV).

Moreover, it can implement also in the following aspects in the range which does not deviate from the meaning of this invention.

The above embodiment is changed so that only one side of the seat surface 32a of the valve seat 32 and the opening / closing surface 31a of the valve body 31 is formed of a material of high hardness. Even in this manner, the same effects as those of the above embodiment (reduction of refrigerant gas leakage in the entire closed state of the control valve CV) can be obtained. However, of course, this effect is surely exhibited in the above-described embodiment in which both the seat face 32a of the valve seat 32 and the open / close face 31a of the valve body portion 31 are made of a hard material.

In the above embodiment, the seat surface 32a of the valve seat 32 is made of a material of high hardness by surface hardening of the valve seat 32 material by nickel-phosphorus plating. The sheet surface 32a is changed by surface hardening of the valve seat 32 material by any one of nickel plating, nickel-phosphorus-boron plating, nickel-boron plating, nickel-boron-tungsten plating, chromium plating and copper plating. ) Is made of a hard material.

Alternatively, the high hardness of the seat surface 32a of the valve seat 32 is not limited to the surface hardening of the material by plating, and the material of the valve seat 32 material by any one of ion nitriding, gas soft nitriding and salt bath nitriding. It may be by surface hardening.

Alternatively, the material of the valve seat 32 is made of carburized steel, and the seat surface 32a is made of a material of high hardness by surface hardening by carburization of the material.

In the above embodiment, the opening and closing surface 31a of the valve body portion 31 is made of a material of high hardness by surface hardening of the material of the valve body portion 31 by salt bath nitriding. By changing this, the opening and closing surface 31a is made of a high hardness material by surface hardening of the material of the valve body part 31 by other nitriding treatment such as ion nitriding or gas soft nitriding.

Or the high hardness of the opening-closing surface 31a of the valve body part 31 is not limited to the surface hardening of the raw material by nitriding process. The high hardness of the opening / closing surface 31a of the valve body 31 is any one of nickel plating, nickel-phosphorus plating, nickel-phosphorus-boron plating, nickel-boron plating, nickel-boron-tungsten plating, chromium plating and copper plating. It may be by surface hardening of the raw material of the valve body part 31 by this.

Or the raw material of the valve body part 31 (valve rod 25) is made into carburizing steel, and the opening-and-closing surface 31a is comprised by the material of high hardness by surface hardening by carburizing of this raw material.

The material of the valve seat 32 is not limited to brass, but may be other copper material, aluminum material, or SUS.

In the above embodiment, the control valve CV is configured to change the opening degree of the air supply passage 7 connecting the high pressure region (oil separator 4) and the crank chamber 5 of the refrigerating cycle. It is embodied as a so-called inlet-side control valve for regulating pressure. The so-called discharge side which controls the pressure of the crank chamber 5 by changing the opening degree of the bleeding passage 6 which connects the crank chamber 5 and the low pressure area | region (for example, the suction chamber 2) of a refrigeration cycle by changing this. It is specified as a control valve.

In the above embodiment, the control valve CV is embodied as a so-called external control valve which positions the valve body 31 autonomously in accordance with a change in this pressure difference so as to maintain a set differential pressure determined according to the amount of power supply from the outside. It became. However, the present invention is not limited to being embodied in an external control valve, but may be embodied in an internal control valve or a simple solenoid valve.

The technical idea grasped | ascertained by the said embodiment is described.

(1) The control valve of the variable displacement compressor according to claim 1, wherein both the seat surface of the valve seat and the opening and closing surface of the valve body are made of a material of high hardness.

(2) The control valve of the variable displacement compressor according to any one of claims 1 to 5 or the technical idea (1), wherein the high hardness material is a Vickers hardness material of 500 or more.

According to the present invention, it is possible to provide a control valve of a variable displacement compressor capable of reducing the leakage of refrigerant gas in the entire closed state.

Claims (5)

It is used in a variable displacement compressor that can change the discharge capacity according to the pressure of the crank chamber while constituting the refrigeration cycle. The pressure of the crank chamber is changed by changing the opening degree of the passage connecting the crank chamber and the high pressure region or the low pressure region of the refrigeration cycle. In the control valve to regulate, A control valve of a variable displacement compressor, characterized in that at least one of the seat surface of the valve seat and the opening / closing surface of the valve body for adjusting the opening degree of the passage is made of a high hardness material. 2. The control valve of a variable displacement compressor according to claim 1, wherein both the seat surface of the valve seat and the open / close surface of the valve body are made of high hardness material, and the seat surface and the open / close surface are made of different materials. The method of claim 1 or 2, wherein the high hardness material is nickel plating, nickel-phosphorus plating, nickel-boron plating, nickel-phosphorus-boron plating, nickel-boron-tungsten plating, chromium plating, copper plating, dye bath A control valve of a variable displacement compressor in which the material is hardened by nitriding, ion nitriding, gas soft nitriding or carburizing. The oil separator according to claim 1 or 2, wherein an oil separator for separating lubricating oil from a refrigerant gas flowing in the region is arranged in the high pressure region of the refrigerating cycle, and the passage connects the oil separator and the crank chamber to provide oil. Control valve of a variable displacement compressor that also serves as a supply passage for supplying the lubricating oil separated by the separator to the crank chamber. The control valve according to claim 1 or 2, wherein carbon dioxide is used as the refrigerant of the refrigerating cycle.