WO2011037334A1

WO2011037334A1 - Control valve for variable displacement compressor

Info

Publication number: WO2011037334A1
Application number: PCT/KR2010/005922
Authority: WO
Inventors: Ki Baek Song; Soon Il Jung; Hyo Yeol Lee
Original assignee: Inziplus Co.,Ltd.
Priority date: 2009-09-22
Filing date: 2010-09-01
Publication date: 2011-03-31
Also published as: KR100947642B1

Abstract

The present invention provides a control valve configured to optimize the operating capacity of a variable displacement compressor used in an air controlling system based on cooling load and target temperature. According to the present invention, a new type of structure, in which a diaphragm assembly (16) and a plunger assembly (17) are arranged up and down and connected to each other, is provided to simplify the structure, reduce the number of parts, and significantly reduce the size of the overall control valve. Moreover, a new type of diaphragm assembly (16), in which a metal contact member (16b) is reinforced in the contact area of a diaphragm (16a), is provided to prevent wear or damage even by frequent contact with a plunger (17a) and improve the durability of the diaphragm (16a). Furthermore, the sliding area of the plunger (17a) is minimized to two areas to reduce a difference in pressure due to a difference in frictional force between up and down movements, and thus it is possible to precisely perform variable displacement control.

Description

CONTROL VALVE FOR VARIABLE DISPLACEMENT COMPRESSOR

The present invention relates to a control valve for a variable displacement compressor and, more particularly, to a control valve configured to optimize the operating capacity of a variable displacement compressor used in an air controlling system based on cooling load and target temperature.

Typically, a cooling circuit of an air conditioning system for a vehicle includes a condenser, an expansion valve, an evaporator, a compressor, etc.

The compressor draws and compresses refrigerant gas from the evaporator and discharges the refrigerant to the condenser.

The evaporator performs heat exchange between the refrigerant flowing through the cooling circuit and the indoor air of the vehicle.

The temperature of the air, which passes through the evaporator, according to the magnitude of the heat load or cooling load is transmitted to the refrigerant flowing through the evaporator, and thus the pressure of the refrigerant gas at the outlet or downstream side of the evaporator reflects the magnitude of the cooling load.

This compressor used in the cooling circuit utilizes the power of an engine, in which the rotational speed varies according to the running state, and thus it is impossible to control the rotational speed of the compressor. Therefore, a variable displacement compressor, which can vary the discharge capacity of the refrigerant to obtain an appropriate cooling capacity without restriction on the rotational speed of the engine, has recently been used.

According to a typical variable displacement compressor, a Swash plate installed in a crank chamber to change the tilt angle is driven by rotational movement of a rotating shaft such that a piston reciprocating in a direction parallel to the rotating shaft draws and compresses the refrigerant of a suction chamber and discharges the refrigerant to a discharge chamber. Here, the tilt angle of the Swash plate is changed by varying the pressure of the crank chamber, thereby changing the amount of refrigerant discharged.

Here, the pressure of the crank chamber is controlled by a control valve of the variable displacement compressor.

Such a control valve is configured to control the pressure Pc of the crank chamber by controlling the amount of refrigerant discharged from the discharge chamber and introduced into the crank chamber at a discharge pressure Pd, and the amount of refrigerant introduced into the crank chamber is controlled based on a suction pressure Ps of the suction chamber.

The control valve includes a bellows-type or diaphragm-type decompression section for detecting the suction pressure Ps, a valve section for opening and closing a path between the discharge chamber and the crank chamber based on the suction pressure Ps detected by the decompression section, and a solenoid for varying a predetermined value of the decompression section in response to an external current.

Recently, a variable displacement compressor having a structure, in which the engine and the rotating shaft of the compressor are directly connected to each other without the use of an electromagnetic clutch installed between the engine and the rotating shaft of the compressor to transmit or cut off the driving power of the engine, has been widely used. This type of variable displacement compressor provides the advantage of eliminating the expensive electromagnetic clutch.

In connection with this, the control valve has a structure corresponding to the compressor having the direct connection structure.

For example, the control valve includes a valve section for opening and closing a path between a discharge chamber and a crank chamber, a solenoid for generating an electromagnetic force causing the valve section to operate in the closing direction, and a decompression section for causing the valve section to operate in the opening direction as suction pressure Ps is decreased compared to the atmospheric pressure, which is disclosed in Korean Patent Publication No. 10-2004-0036578.

Therefore, when the solenoid is not energized, the valve section is in a completely open state, the pressure Pc of the crank chamber can be maintained approximately equal to the discharge pressure Pd, and the Swash plate is substantially perpendicular to the rotating shaft, thereby allowing the variable displacement compressor to operate at a minimum capacity.

This means that the use of the electromagnetic clutch can be eliminated as the discharge capacity can be maintained at substantially zero although the engine and the rotating shaft are directly connected to each other.

However, the above-described control valve for the variable displacement compressor has the following drawbacks.

Firstly, since a diaphragm is disposed between upper and lower plungers and connected to each other, the number of parts is increased, the overall size (especially, the upper and lower length) is increased, and thus the structure is complicated.

Secondly, in the relationship between the plungers and the diaphragm during operation, the diaphragm made of a mixture of fabric and rubber may be worn out or damaged by frequent contact with the plungers, which reduces the durability, thereby causing refrigerant leakage.

Various supplementary devices are provided to solve these drawbacks, which however causes an increase in the number of parts.

Thirdly, in the case of the plunger operating up and down, it slides over the entire outer circumferential surface, which increases the sliding area. As a result, a significant difference in pressure occurs due to a difference in frictional force between up and down movements, which causes the occurrence of an error, thereby making it difficult to control the control valve.

Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control valve for a variable displacement compressor, which can simplify the structure, reduce the number of parts, and significantly reduce the size of the overall control valve by providing a new type of structure in which a diaphragm assembly and a plunger assembly are arranged up and down and connected to each other.

Another object of the present invention is to provide a control valve for a variable displacement compressor, which can prevent wear or damage even by frequent contact with a plunger by providing a new type of diaphragm assembly in which a metal contact member is reinforced in the contact area of a diaphragm.

Still another object of the present invention is to provide a control valve for a variable displacement compressor, which can precisely perform variable displacement control by minimizing the sliding area of a plunger to reduce a difference in pressure due to a difference in frictional force between up and down movements.

To accomplish the above objects of the present invention, there is provided a control valve for a variable displacement compressor, the control valve including: a housing including a coil provided inside thereof; a valve body including paths connected to a discharge chamber and a crank chamber, respectively, and a path for providing suction pressure, the valve body being connected to the bottom of the housing; an atmospheric section created along an axial line at the top of the housing and forming a diaphragm atmospheric side; a diaphragm assembly positioned at the bottom of the atmospheric section and operating at a suction pressure of a decompression section created at the bottom; a plunger assembly slidably positioned at the bottom of the diaphragm assembly and concentrically arranged in the coil to be moved up and down by an electromagnetic force to open and close the paths between the discharge chamber and the crank chamber; and a connector mold covering the top of the housing and connected thereto.

The diaphragm assembly may include a disc-shaped elastic membrane member and a circular metal contact member inserted into the center of the membrane member so as to maintain the durability.

The plunger assembly may include a plunger supported up and down by first and second plunger springs, a push rod connected to the top of the plunger along an axial line and being in contact with the diaphragm assembly, and a valve rod connected to the bottom of the plunger along the axial line to open and close the paths using a valve sheet provided at the bottom such that only two sliding areas are provided for up and down movements of the plunger assembly to minimize a difference in frictional force between up and down movements, thereby precisely performing variable displacement control.

To accomplish the above objects of the present invention, there is provided a control valve for a variable displacement compressor, the control valve including: a housing including a coil provided inside thereof; a valve body including paths connected to a discharge chamber and a crank chamber, respectively, and a path for providing suction pressure, the valve body being connected to the bottom of the housing; an atmospheric section created along an axial line at the top of the housing and forming a bellows atmospheric side; a bellows positioned to accommodate the atmospheric section and operating at a suction pressure of a decompression section created at the bottom; a plunger assembly slidably positioned at the bottom of the bellows and concentrically arranged in the coil to be moved up and down by an electromagnetic force to open and close the paths between the discharge chamber and the crank chamber; and a connector mold covering the top of the housing and connected thereto.

The control valve of the present invention provides the following advantages:

Firstly, the control valve has a simplified structure, in which a plunger means and a diaphragm means are assembled and arranged up and down, including a diaphragm section, a plunger section, and a valve section, and thus it is possible to reduce the number of parts, simplify the assembly structure, and significantly reduce the size of the overall control valve, which is advantageous in terms of design layout.

Secondly, when a plunger assembly is in contact with a diaphragm assembly, the contact between metals is maintained to prevent wear or damage of a diaphragm during contact operation, and thus it is possible to ensure excellent durability and prevent refrigerant leakage, thereby improving the overall quality.

Thirdly, only two sliding areas are provided for up and down movements of a plunger assembly, and a Teflon bush, for example, is provided in at least one area, and thus it is possible to minimize the friction during the operation of the plunger assembly and reduce a difference in frictional force between up and down movements, thereby precisely performing variable displacement control.

Fourthly, a connector mold is formed as a separate assembly, and thus it is possible to facilitate the manipulation of an adjusting screw.

Fifthly, a diode, which has a difficulty in insert injection, is built in the connector mold, and thus it is possible to improve productivity and assemblability.

Sixthly, the connector mold is assembled with a coil overmold in a curling manner, and thus it is possible to facilitate the assembly without additional processes such as bonding, ultrasonic welding, hook, etc.

Seventhly, a washer and a rotating part are employed during spring adjustment, and thus it is possible to prevent the spring from being twisted.

Lastly, the control valve is in an open state by the spring even when a diaphragm or bellows is compressed by high suction pressure Ps, and thus it is possible to apply the control valve to both cases where an electromagnetic clutch is provided or not.

FIG. 1 is a perspective view showing a control valve in accordance with an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the control valve in accordance with an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a closed state of the control valve in accordance with an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing an opened state of the control valve in accordance with an embodiment of the present invention.

FIG. 5 is a perspective view showing a control valve in accordance with another embodiment of the present invention.

FIG. 6 is an exploded perspective view showing the control valve in accordance with another embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a closed state of the control valve in accordance with another embodiment of the present invention.

FIG. 8 is a cross-sectional view showing an opened state of the control valve in accordance with another embodiment of the present invention.

[Description of Reference Numerals]

10: coil 11: housing

12a, 12b & 12c: paths

13: valve body 14: atmospheric section

15: decompression section

16: diaphragm assembly 16a: membrane member

16b: contact member 17: plunger assembly

17a: plunger 17b: push rod

19: first plunger spring

20: second plunger spring

21: valve sheet 22: Teflon bush

23: spring 24: adjusting screw

25: bellows 26: upper core

27: lower core 28: housing body

29: overmold 30: terminal

31: atmospheric hole 32a & 32b: flow paths

33: bobbin 34: disc

35: diode 36: stopper

37: screw

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIGS. 1 & 2 are perspective views showing a control valve in accordance with an embodiment of the present invention, and FIGS. 3 and 4 are cross-sectional views showing closed and opened states of the control valve in accordance with an embodiment of the present invention.

As shown in FIGS. 1 to 4, the control valve for detecting suction pressure Ps using a diaphragm has a simple structure in which a diaphragm assembly 16, a plunger assembly 17, a valve body 13, an atmospheric section 14, and a decompression section 15 are arranged in an appropriate manner. As a result, the design structure is simplified, the number of parts is minimized, and the size of the overall control valve is significantly reduced.

For this purpose, the control valve includes a cylindrical housing 11 having an overmold 29 provided on the inner circumference and a housing body 28 provided at the bottom. A coil 10 for generating an electromagnetic force to operate the plunger assembly 17 is concentrically connected to the inside of the housing 11.

The coil 10 is wound on a bobbin 33 and a disc 34 is provided at the top of the coil 10.

The coil 10 is electrically connected to a connector mold 18, which will be described later, by means of terminals 30 to be operated under the control of a controller (not shown).

A valve body 13 for providing a flow path of fluid between a discharge chamber and a crank chamber is provided at the bottom of the housing 11 and connected to the bottom of the housing body 28 of the housing 11.

The valve body 13 includes a total of three paths such as

paths

12a and 12b connected to the discharge chamber and the crank chamber, respectively, and a path 12c for providing suction pressure Ps to the decompression section 15. The fluid connection between the discharge chamber and the crank chamber is made through the respective paths, and the suction pressure according to cooling load is applied thereto.

Here, the decompression section 15, in which the suction pressure Ps acts, is created at the bottom of the diaphragm assembly 16 and connected to the path 12c of the valve body 13 through

flow paths

32a and 32b formed in a plunger 17a and a push rod 17b of the plunger assembly 17.

Moreover, an atmospheric section 14 surrounded by an upper core 26 is provided along an axial line at the top of the housing 11.

Here, the atmospheric section 14 may be created by drilling an atmospheric hole 31 having a diameter of approximately 1.5 mm in a connector mold 18.

A spring adjusting device 25 for setting and adjusting the working range of the diaphragm is installed in the atmospheric section 14.

The spring adjusting device 25 includes a spring 23 pressing the top of the diaphragm assembly 16 and an adjusting screw 24 closing the top of the spring 23. The spring adjusting device 25 can adjust the tensile strength of the spring by turning the adjusting screw 24 connected to the upper coil 26 by means of a driver.

Here, a washer and a rotating part may be inserted into the bottom of the spring 23 to prevent the spring 23 from being twisted during spring adjustment.

The top of the housing 11 is covered and finished by the separately prepared connector mold 18.

A diode 35 is mounted in the connector mold 18. Terminals 30 are provided inside and outside of the connector mold 18 to be electrically connected to the coil 10 and external power source, respectively. Especially, when the connector mold 18 is assembled with the housing 11, it is assembled with an overmold 29 of the housing 11 in a curling manner, and thus it is possible to facilitate the assembly without additional processes such as bonding, ultrasonic welding, hook, etc.

Here, the connector mold 18 is formed separately from the housing 11 and assembled thereto, and thus it is possible to easily adjust the adjusting screw 24 at the top thereof.

In other words, it is preferable that the connector mold be formed as a separate assembly to facilitate the adjustment of the adjusting screw at the top thereof.

Especially, the present invention provides a diaphragm assembly 16 exhibiting excellent durability.

The diaphragm assembly 16 includes a disc-shaped elastic membrane member 16a formed of a typical diaphragm material and a circular metal contact member 16b inserted into the center of the membrane member 16a. As the contact member 16b is in contact with the push rod 17b of the plunger assembly 17, the contact between metals is maintained to prevent the diaphragm assembly 16 from being worn out or damaged even by frequent contact, thus improving the durability of the diaphragm assembly 16.

The diaphragm assembly 16 is inserted between upper and

lower cores

26 and 27 using the edge of the membrane member 16a and is in contact with the atmospheric section 14 at the top and the decompression section 15 at the bottom.

Therefore, the diaphragm assembly 16 operates according to the suction pressure of the decompression section 15 to open and close the

paths

12a and 12b together with the plunger assembly 17.

Moreover, the present invention provides the plunger assembly 17 which can effectively serve as a valve body that opens and closes the paths as well as the connection with the diaphragm assembly 16 with reduced size.

The plunger assembly 17 is concentrically arranged in the coil 10 and slidably positioned at the bottom of the diaphragm assembly 16. The plunger assembly 17 is moved up and down by the electromagnetic force of the coil 10 and connected to the diaphragm assembly 16 to open and close the

paths

12a and 12b of the valve body 13, thus controlling the flow rate.

For this purpose, the plunger assembly 17 includes a cylindrical plunger 17a, and the push rod 17b and a valve rod 17c connected to the top and bottom of the plunger 17a, respectively.

The push rod 17b is slidably connected to the contact member 16b of the diaphragm assembly 16, and the valve rod 17c extends to the path 12a of the valve body 13 to control the flow of fluid using a valve sheet 21 provided at the bottom of the control valve.

The plunger assembly 17 is elastically supported by a first plunger spring 19 at the top and a second plunger spring 20 at the bottom to be moved up and down. Here, the first plunger spring 19 has an elastic force greater than that of the second plunger spring 20 such that the plunger assembly 17 receives a force in a direction that opens the

paths

12a and 12b.

As such, since the plunger assembly 17 is configured to operate together with the diaphragm assembly 16, the plunger is supported by the spring to open the paths even when the diagram is compressed by high suction pressure Ps, and thus it is possible to apply the control valve to both cases where an electromagnetic clutch is provided or not.

Moreover, the plunger assembly 17 has a structural feature that can slide with a minimum surface during up and down movement.

That is, the plunger assembly 17 is supported by the push rod 17b at the lower core 27 and the valve rod 17c at the valve body 13 such that it can slide on only two (up and down) sliding areas.

Especially, a Teflon bush 22 is provided in the lower core 27 where the push rod 17b slides, thus minimizing the friction of the push rod 17b.

Since the plunger assembly 17 slides on only two sliding areas, it is possible to reduce the friction area of the plunger assembly 17 during up and down movement, and thus it is possible to ensure the functionality of the plunger assembly 17, thereby providing precise control.

The operation of the control valve configured in the above manner will be described below.

FIGS. 3 and 4 show the operation states of the control valve. As the operation of the control valve is performed in real time, the control valve can move up and down in real time without stopping the operation of the diaphragm or plunger.

As shown in FIG. 3, when high suction pressure Ps transmitted through the path 12c of the valve body 13 is applied to the decompression section 15 through the

flow paths

32a and 32b as the variable displacement compressor is operated, the diaphragm assembly 16 moves up while compressing the spring 23. At the same time, when a maximum control current is applied to the coil 10, the plunger assembly 17 also moves up while pushing the diaphragm assembly 16 using the push rod 17b by the electromagnetic force, and thus the valve sheet 21 at the valve rod 17c completely closes the path 12a.

As a result, the path from the discharge chamber to the crank chamber is cut off, and thus the variable displacement compressor can perform the operation at the maximum capacity and at high speed.

As shown in FIG. 4, when the suction pressure Ps of a suction chamber is sufficiently lowered as the variable displacement compressor continues to operate at the maximum capacity, the pressure applied to the decompression section 15 is also reduced, and thus the diaphragm assembly 16 returns to its original position.

That is, the diaphragm assembly 16 moves down while pushing the push rod 17b of the plunger assembly 17 downward by the force of the spring 23.

Here, the diaphragm assembly 16 moves down to a position where the suction pressure Ps, the weight of the first and second plunger springs 19 and 20, and the electromagnetic force of the coil 10 are balanced with one another.

Therefore, the valve sheet 21 at the valve rod 17c of the plunger assembly 17 is spaced apart from the path 12a of the valve body 13 and is set to a predetermined opening degree, and thus the refrigerant at a discharge pressure Pd is controlled to a flow rate according to the opening degree and is introduced into the crank chamber such that the variable displacement compressor operates at a capacity corresponding to the current control.

If the control current applied to the coil 10 is constant, the diaphragm assembly 16 controls the opening degree of the plunger assembly 17 by detecting the suction pressure Ps, i.e., by the pressure of the decompression section 15.

For example, if the suction pressure Ps is high as the cooling load is increased, the diaphragm assembly 16 is displaced upward, and thus the plunger assembly 17 is also moved up to decrease the opening degree of the path such that the variable displacement compressor operates to increase the discharge capacity.

On the contrary, if the suction pressure Ps is low as the cooling load is decreased, the diaphragm assembly 16 is displaced downward and thus the opening degree of the path is increased such that the variable displacement compressor operates to reduce the discharge capacity and controls the suction pressure PS to be maintained constant.

FIGS. 5 & 6 are perspective views showing a control valve in accordance with another embodiment of the present invention, and FIGS. 7 and 8 are cross-sectional views showing closed and opened states of the control valve in accordance with another embodiment of the present invention.

As shown in FIGS. 5 to 8, the control valve in accordance with another embodiment of the present invention is a bellows-type control valve. The same or equivalent elements as those in FIGS. 1 to 4 are designated by the same reference numerals and their detailed description will be omitted.

A bellows 25 is interposed between an atmospheric section 14 where the atmospheric pressure acts and a decompression section 15 where suction pressure Ps acts. That is, the bellows 25 is inserted and supported between an upper core 26 and a lower core 27 through a flange portion at the top thereof.

Here, the bellows 25 may be joined to the lower core 27 by blazing or using an O-ring.

A plunger assembly 17 is slidably connected to the bottom of the bellows 25 using a push rod 17b.

Here, the decompression section 15 is also connected to a plunger 17a through a path 12c at a valve body 13 and

flow paths

32a and 32b at the push rod 17b, and the atmospheric section 14 is also connected to the outside through an atmospheric hole 31 at a connector mold 18.

Especially, a stopper 36 formed in the connector mold 18 is positioned in the bellows 25, and thus an excessive compression is prevented when the bellows 25 is compressed by the pressure generated in the control valve.

Meanwhile, the connector mold 18 may be integrated with a coil overmold 29 differently from the previous embodiment.

That is, it is possible to adjust the connector mold 18 using a screw 37 fastened to the bottom of the valve body 13, and thus the connector mold 18 can be integrated with the coil overmold 29, instead of a separate assembly.

Therefore, as shown in FIG. 7, when high suction pressure Ps transmitted through the path 12c of the valve body 13 is applied to the decompression section 15 through the

flow paths

32a and 32b as the variable displacement compressor is operated, the bellows 25 is compressed and moves up. At the same time, when a maximum control current is applied to the coil 10, the plunger assembly 17 also moves up while pushing the bellows 25 using the push rod 17b by the electromagnetic force, and thus the valve sheet 21 at the valve rod 17c completely closes the path 12a.

As shown in FIG. 8, when the suction pressure Ps of a suction chamber is sufficiently lowered as the variable displacement compressor continues to operate at the maximum capacity, the pressure applied to the decompression section 15 is also reduced, and thus the bellows 25 moves down while pushing the push rod 17b of the plunger assembly 17 downward by its elastic restoring force.

That is, the bellows 25 moves down to a position where the suction pressure Ps, the weight of the first and second plunger springs 19 and 20, and the electromagnetic force of the coil 10 are balanced with one another.

While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

A control valve for a variable displacement compressor, the control valve comprising:a housing 11 including a coil 10 provided inside thereof;a valve body 13 including paths 12a and 12b connected to a discharge chamber and a crank chamber, respectively, and a path 12c for providing suction pressure Ps, the valve body 13 being connected to the bottom of the housing 11;an atmospheric section 14 created along an axial line at the top of the housing 11 and forming a diaphragm atmospheric side;a diaphragm assembly 16 positioned at the bottom of the atmospheric section 14 and operating at a suction pressure of a decompression section 15 created at the bottom;a plunger assembly 17 slidably positioned at the bottom of the diaphragm assembly 16 and concentrically arranged in the coil 10 to be moved up and down by an electromagnetic force to open and close the paths 12a and 12b between the discharge chamber and the crank chamber; anda connector mold 18 covering the top of the housing 11 and connected thereto.
The control valve for a variable displacement compressor of claim 1, wherein the diaphragm assembly 16 comprises a disc-shaped elastic membrane member 16a and a circular metal contact member 16b inserted into the center of the membrane member 16a.
The control valve for a variable displacement compressor of claim 1, wherein the plunger assembly 17 comprises a plunger 17a supported up and down by first and second plunger springs 19 and 20, a push rod 17b connected to the top of the plunger 17a along an axial line and being in contact with the diaphragm assembly 16, and a valve rod 17c connected to the bottom of the plunger 17a along the axial line to open and close the paths 12a and 12b using a valve sheet 21 provided at the bottom.
The control valve for a variable displacement compressor of claim 3, wherein the first plunger spring 19 has an elastic force greater than that of the second plunger spring 20 to produce a force that pushes the plunger assembly 17 to open the paths 12a and 12b.
The control valve for a variable displacement compressor of claim 1 or 3, wherein the plunger assembly 17 is slidably supported by the push rod 17b at a lower core 27 and the valve rod 17c at the valve body 13.
The control valve for a variable displacement compressor of claim 3, wherein a Teflon bush 22 is provided in the lower core 27 where the push rod 17b slides, thereby minimizing the friction of the push rod 17b.
A control valve for a variable displacement compressor, the control valve comprising: a housing 11 including a coil 10 provided inside thereof;a valve body 13 including paths 12a and 12b connected to a discharge chamber and a crank chamber, respectively, and a path 12c for providing suction pressure Ps, the valve body 13 being connected to the bottom of the housing 11;an atmospheric section 14 created along an axial line at the top of the housing 11 and forming a bellows atmospheric side;a bellows 25 positioned to accommodate the atmospheric section 14 and operating at a suction pressure of a decompression section 15 created at the bottom;a plunger assembly 17 slidably positioned at the bottom of the bellows 25 and concentrically arranged in the coil 10 to be moved up and down by an electromagnetic force to open and close the paths 12a and 12b between the discharge chamber and the crank chamber; anda connector mold 18 covering the top of the housing 11 and connected thereto.