JP2007177627A - Discharge capacity control valve of variable displacement compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge capacity control valve of a variable displacement compressor inhibiting action of discharge pressure to a valve element in a valve hole opening/closing direction more efficiently than that of patent document 1, inhibiting change of control characteristic with time and easy for insertion of the other end of the valve element into a support hole as compared with that of the patent document 1. <P>SOLUTION: The discharge capacity control valve comprises a valve chamber communicating with a crank chamber and with a discharge pressure area though the valve hole and a communication hole, the valve element disposed in the valve chamber and having an end opening/closing the valve hole, a valve housing having the support hole slidably supporting the valve element other end and receiving the valve element with its other end shielded from the discharge pressure area, and a means driving the valve element in the valve hole opening/closing direction, wherein the valve hole and a valve seat around a valve hole opening are formed in a valve seat forming body which is separate from the valve housing and is comprised of material of a higher hardness than the valve housing, the valve seat forming body is fitted and fixed to a receiving hole of a larger diameter than the support hole in the valve housing and the communication and valve holes communicate with each other through the receiving hole. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a discharge capacity control valve of a variable capacity compressor.

A valve chamber that communicates with the crank chamber and communicates with the discharge pressure region via the valve hole and the communication hole, a valve body having one end portion disposed in the valve chamber for opening and closing the valve hole, and the other end portion of the valve body A valve housing that has a support hole that slidably supports the valve body and shuts off the other end of the valve body from the discharge pressure region and accommodates the valve body, and driving means that drives the valve body in the valve hole opening and closing direction, Patent Document 1 discloses a discharge capacity control valve of a variable capacity compressor in which a valve hole and a valve seat around a valve hole opening are formed in a valve housing.
Patent Document 1 discloses a discharge in which discharge pressure does not act on the valve body in the valve hole opening / closing direction by making the cross-sectional area of the other end of the valve body inserted through the support hole equal to the cross-sectional area of the valve hole. It is described that a capacity control valve can be realized.
JP 2000-18420 A

In the discharge capacity control valve of Patent Document 1, since the contact surface between the valve body and the valve seat is flat, the discharge pressure receiving area of the valve body when the valve is closed varies depending on the roughness of the contact surface. Therefore, in the capacity control valve of Patent Document 1, even if the cross-sectional area of the other end of the valve body inserted through the support hole is equal to the cross-sectional area of the valve hole, the discharge pressure in the valve hole opening / closing direction with respect to the valve body Cannot be completely prevented, and the control suction pressure may vary depending on the discharge pressure.
The valve housing is usually made of a soft material with good machinability, such as brass or aluminum alloy. If the valve body is repeatedly opened and closed over a long period of time, the valve seat surface will wear out and the valve body will be discharged. The pressure receiving area may change, and the suction pressure control characteristic may change over time.
In the capacity control valve of Patent Document 1, the valve hole, the support hole, and the connecting portion thereof have the same diameter, and the communication hole intersects the connecting portion. Since these holes are formed by drilling, processing burrs are generated at the intersections between the connection portions and the communication holes. Since it is difficult to completely remove the processing burr, there is a possibility that the operation of inserting the other end of the valve body into the support hole may be hindered by the remaining burr.
The present invention has been made in view of the above problems, and the action of the discharge pressure in the valve hole opening / closing direction on the valve body is more effectively prevented than the capacity control valve of Patent Document 1, and the change in control characteristics over time is prevented. An object of the present invention is to provide a discharge capacity control valve of a variable capacity compressor that is suppressed and can be inserted into a support hole at the other end of the valve body more easily than the capacity control valve of Patent Document 1.

In order to solve the above problems, in the present invention, a valve chamber that communicates with a crank chamber and communicates with a discharge pressure region through a valve hole and a communication hole, and one end portion disposed in the valve chamber has a valve hole. A valve body that has a support hole that slidably supports the other end portion of the valve body, and that shuts off the other end of the valve body from the discharge pressure region and accommodates the valve body, Drive means for driving in the valve hole opening and closing direction, the valve hole and the valve seat around the valve hole opening are formed separately from the valve housing and formed of a material having higher hardness than the valve housing. The valve seat forming body is fitted and fixed to a receiving hole having a diameter larger than that of the support hole formed in the valve housing, and the communication hole and the valve hole communicate with each other through the receiving hole. A discharge capacity control valve for a capacity compressor is provided.
In the discharge capacity control valve according to the present invention, since the valve seat is formed on the valve seat forming body made of a material harder than the valve housing, wear of the valve seat is suppressed, and the discharge pressure receiving area of the valve body over time is reduced. Change is suppressed. As a result, changes with time in the control characteristics are suppressed.
In the discharge capacity control valve according to the present invention, since the communicating hole intersects the accommodating hole having a diameter larger than that of the support hole, even if a processing burr generated at the intersecting portion between the accommodating hole and the communicating hole remains, the valve body This does not hinder the operation of inserting the other end of the through hole into the support hole. Therefore, the operation of inserting the other end of the valve body into the support hole is easier than the capacity control valve of Patent Document 1.

In a preferred aspect of the present invention, the valve seat abutment surface of the valve body is a tapered surface, and abuts against the periphery of the valve hole opening when the valve is closed.
Since the contact between the tapered surface and the peripheral edge of the opening is a substantially linear contact, the surface roughness of the member does not affect the discharge pressure receiving area of the valve body when the valve is closed. As a result, the action of the discharge pressure in the valve hole opening / closing direction on the valve body is more effectively prevented than in the capacity control valve of Patent Document 1.

In the preferable aspect of this invention, the connection part of a valve hole and a valve seat surface is a corner | angular.
Since the connection portion between the valve hole and the valve seat surface becomes a corner, the contact between the tapered surface and the peripheral edge of the opening further approaches the line contact. As a result, the action of the discharge pressure in the valve hole opening / closing direction on the valve body is further effectively prevented. The corner is preferably R0.5 or less or C0.5 or less.

In a preferred aspect of the present invention, the capacity control valve is provided with a drop prevention means for preventing the valve seat forming body from falling off.
Since the valve seat forming body receives a differential pressure between the discharge pressure and the crank pressure, a drop prevention means may be provided to prevent the valve seat forming body from falling out of the accommodation hole.

In a preferred aspect of the present invention, the driving means is connected to the other end of the valve body, and has an autonomous control mechanism having a pressure-sensitive member that is displaced by a change in suction pressure to drive the valve body, and electromagnetic force is applied to the valve body. And an external control mechanism that changes the suction pressure control characteristic of the autonomous control mechanism by acting.
The suction pressure can be optimally controlled according to the external environment.

In a preferred aspect of the present invention, the driving means is connected to the other end of the valve body, and is autonomous with a pressure-sensitive member that is displaced by a change in pressure difference between two pressure monitoring points of the refrigerant circuit and drives the valve body. A control mechanism and an external control mechanism that changes the differential pressure control characteristic of the autonomous control mechanism by applying electromagnetic force to the valve body are provided.
The pressure difference between the pressure monitoring points can be optimally controlled according to the external environment.

In the compressor according to the present invention, since the valve seat is formed on the valve seat forming body made of a material having a hardness higher than that of the valve housing, the wear of the valve seat is suppressed, and the discharge pressure receiving area of the valve body changes over time. It is suppressed. As a result, changes with time in the control characteristics are suppressed.
In the compressor according to the present invention, since the communication hole intersects with the housing hole having a diameter larger than that of the support hole, even if a processing burr generated at the intersection between the housing hole and the communication hole remains, The operation of inserting the end portion into the support hole is not hindered. Therefore, the operation of inserting the other end of the valve body into the support hole is easier than the capacity control valve of Patent Document 1.

  A discharge capacity control valve of a variable capacity compressor according to an embodiment of the present invention will be described.

As shown in FIG. 1, a variable capacity swash plate compressor 100 includes a cylinder block 101 having a plurality of cylinder bores 101a, a front housing 102 provided at one end of the cylinder block 101, and a cylinder block via a valve plate 103. And a rear housing 104 provided at the other end of 101.
A drive shaft 106 is disposed across the crank chamber 105 defined by the cylinder block 101 and the front housing 102. The drive shaft 106 is inserted through the swash plate 107. The swash plate 107 is coupled to a rotor 108 fixed to the drive shaft 106 via a connecting portion 109 and is supported by the drive shaft 106 so that the tilt angle is variable. A coil spring 110 is disposed between the rotor 108 and the swash plate 107 to urge the swash plate 107 toward the minimum inclination angle. On the opposite side of the coil spring 110 across the swash plate 107, a coil spring 111 for urging the swash plate 107 in the minimum tilt state in the direction of increasing the tilt angle is disposed.

One end of the drive shaft 106 passes through the boss portion 102a of the front housing 102 and extends to the outside of the housing, and is directly connected to a vehicle engine (not shown) via a power transmission device (not shown) without using an electromagnetic clutch. . A shaft seal device 112 is disposed between the drive shaft 106 and the boss portion 102a.
The drive shaft 106 is supported in the radial direction and the thrust direction by bearings 113, 114, 115, and 116.

A piston 117 is disposed in the cylinder bore 101a, and a pair of shoes 118 housed in a recess 117a at one end of the piston 117 sandwich the outer peripheral portion of the swash plate 107 so as to be slidable relative to each other. The rotation of the drive shaft 106 is converted into a reciprocating motion of the piston 117 via the swash plate 107 and the shoe 118.

A suction chamber 119 and a discharge chamber 120 are formed in the rear housing 104. The suction chamber 119 communicates with the cylinder bore 101a via a communication hole 103a formed in the valve plate 103 and a suction valve (not shown), and the discharge chamber 120 communicates with a discharge hole (not shown) and a communication hole 103b formed in the valve plate 103. Is communicated with the cylinder bore 101a. The suction chamber 119 is connected to an evaporator of a vehicle air conditioner (not shown) through a suction port 104a.
Front housing 102, cylinder block 101, valve plate 103, and rear housing 104 cooperate to drive shaft 106, rotor 108, connecting portion 109, swash plate 107, shoe 118, piston 117, cylinder bore 101a, intake valve, discharge valve. A housing for accommodating a compression mechanism formed by a valve or the like is formed.

A muffler 121 is disposed outside the cylinder block 101. The muffler 121 is formed by joining a bottomed cylindrical lid member 122 separate from the cylinder block 101 to a cylindrical wall 101b erected on the outer surface of the cylinder block 101 via a seal member. . A discharge port 122 a is formed in the lid member 122. The discharge port 122a is connected to a condenser of a vehicle air conditioner (not shown).
A communication passage 123 that allows the muffler 121 to communicate with the discharge chamber 120 is formed across the cylinder block 101, the valve plate 103, and the rear housing 104. The muffler 121 and the communication passage 123 form a discharge passage extending between the discharge chamber 120 and the discharge port 122a, and the muffler 121 forms an expansion space arranged in the middle of the discharge passage. Yes.
A check valve 200 that opens and closes the inlet of the muffler 121 is disposed in the muffler 121.

The front housing 102, the cylinder block 101, the valve plate 103, and the rear housing 104 are adjacent to each other through a gasket (not shown), and are integrally assembled using a plurality of through bolts.

A discharge capacity control valve 300 is attached to the rear housing 104. The discharge capacity control valve 300 adjusts the opening degree of the communication passage 124 between the discharge chamber 120 and the crank chamber 105, and controls the amount of refrigerant gas discharged into the crank chamber 105. The refrigerant gas in the crank chamber 105 is sucked through a gap between the bearings 115 and 116 and the drive shaft 106, a space 125 formed in the cylinder block 101, and an orifice hole 103 c formed in the valve plate 103. Flows into chamber 119.
The discharge capacity control valve 300 can variably control the internal pressure of the crank chamber 105 to variably control the discharge capacity of the variable capacity swash plate compressor 100. The discharge capacity control valve 300 adjusts the energization amount to the built-in solenoid based on the external signal, and the internal pressure of the suction chamber 119 introduced into the pressure sensing chamber of the discharge capacity control valve 300 via the communication path 126 is a predetermined value. Thus, the discharge capacity of the variable capacity swash plate compressor 100 is variably controlled, and the communication passage 124 is forcibly opened by turning off the energization of the built-in solenoid, so that the discharge of the variable capacity swash plate compressor 100 is performed. Control capacity to a minimum. The discharge capacity control valve 300 can optimally control the suction pressure according to the external environment.

The configuration of the discharge capacity control valve 300 will be described in detail.
As shown in FIG. 2, the discharge capacity control valve 300 is disposed in a pressure-sensitive chamber 302 formed in the valve housing 301, receives the suction pressure through the communication hole 301a, and evacuates the inside to provide a spring. A bellows 303 functioning as a pressure sensing means and a communication path between the discharge chamber 120 and the crank chamber 105 while receiving one end portion of the bellows 303 in a valve chamber 312 formed in the valve housing 301. The valve hole 305a provided in 124 is opened and closed, the other end is slidably supported by the support hole 301b of the valve housing 301, and the other end is connected to the bellows 303, the valve hole 305a and the valve A seat 305b is formed, and a valve seat forming body 305 that is press-fitted and fixed in the receiving hole 301c of the valve housing 301, is formed integrally with the valve body 304, and a movable iron core 306 is press-fitted into one end. The fixed solenoid rod 304a, the solenoid rod 304a is inserted, the fixed iron core 307 is disposed opposite to the movable iron core 306 with a predetermined gap therebetween, and the movable iron core 306 is disposed between the fixed iron core 307 and the movable iron core 306. A spring 308 that biases in the valve opening direction, a cylindrical member 310 that is fixed to the solenoid case 309 by inserting the fixed iron core 307 and the movable iron core 306, and surrounds the cylindrical member 310 and is accommodated in the solenoid case 309. And an electromagnetic coil 311.

The valve housing 301 is made of brass, which is a soft metal with good machinability, and the valve seat forming body 305 is made of stainless steel having a hardness higher than that of brass. The valve body 304 is made of stainless steel. The valve seat contact surface 304b of the valve body 304 is a conical tapered surface, the valve seat 305b is a flat surface, and the joint between the valve hole 305a and the valve seat 305b forms a right angle. The right angle corner is R0.5 or less or C0.5 or less. Accordingly, when the valve is closed, the valve seat abutting surface 304b of the valve body 304 is in line contact with a right-angled corner at the periphery of the opening end of the valve hole 305a.
A communication hole 301 d formed in the valve housing 301 in a direction orthogonal to the valve hole 305 a intersects the accommodation hole 301 c and communicates with the discharge chamber 120. Accordingly, the valve hole 305a and the communication hole 301d communicate with each other through the accommodation hole 301c. The other end of the valve body 304 connected to the bellows 303 is cut off from the accommodation hole 301 c and thus cut off from the discharge chamber 120. The valve chamber 312 communicates with the crank chamber 105 through the communication hole 301e. The communication hole 301 d, the accommodation hole 301 c, the valve hole 305 a, the valve chamber 312, and the communication hole 301 e form a part of the communication path 124 between the discharge chamber 120 and the crank chamber 105.
An autonomous control mechanism having a bellows 303 that is a pressure-sensitive member that is connected to the other end of the valve body 304 and is displaced by a change in suction pressure to drive the valve body 304, a movable iron core 306, a fixed iron core 307, an electromagnetic coil 311, etc. Driving means for driving the valve body 304 in the valve opening / closing direction is formed by an external control mechanism that changes the suction pressure control characteristic of the autonomous control mechanism by applying electromagnetic force to the valve body 304.

The force acting on the valve body 304 is given by equation (1) in FIG. In the discharge capacity control valve 300, a control characteristic is obtained in which the suction pressure decreases as the amount of current supplied to the electromagnetic coil 311 increases.
When the valve is closed, the tapered valve seat abutting surface 304b of the valve body 304 is in line contact with a right-angled corner at the periphery of the opening end of the valve hole 305a. It becomes approximately equal to the area.
Since the valve hole 305a is slightly deformed when the valve seat forming body 305 is press-fitted into the valve housing 301, after the valve seat forming body 305 is press-fitted and fixed to the valve housing 301, the valve hole 305a is finished and processed to have a predetermined hole diameter. Finished in value. The support hole 301b is also finished to the same diameter with the same tool simultaneously with the finishing of the valve hole 305a. Therefore, the cross-sectional areas of the valve hole 305a and the support hole 301b are finished to the same value. The diameter of the pressure-sensitive rod 304c, which is the other end of the valve body 304 slidably supported in the support hole 301b of the valve housing 301, is set slightly smaller (for example, 10 to several tens of microns) than the diameter of the support hole 301b. Therefore, Sv and Sr in Expression (1) are substantially the same value, and Expression (1) in FIG. 3 becomes Expression (2) in FIG.
As can be seen from the equation (2) in FIG. 3, the discharge capacity control valve 300 has a suction pressure control characteristic that is substantially unaffected by the discharge pressure.

Since the valve seat 305b is formed on the valve seat forming body 305 having a hardness higher than that of the valve housing 301, even if the opening / closing operation of the valve body 304 is repeated over a long period of time, wear of the valve seat surface is suppressed. As a result, leakage at the time of valve closing is suppressed, a change with time of the discharge pressure receiving area of the valve body 304 is suppressed, and a change with time of the suction pressure control characteristic is suppressed.
Since the contact between the tapered valve seat contact surface 304b of the valve body 304 and the peripheral edge of the opening end of the valve hole 305a is substantially linear contact, the surface roughness of the member is the discharge pressure receiving area of the valve body 304 when the valve is closed. Does not affect. As a result, the action of the discharge pressure in the valve hole opening / closing direction on the valve body 304 is more effectively prevented than in the capacity control valve of Patent Document 1.
Since the connecting portion between the valve hole 305a and the valve seat 305b forms a right-angled corner, the contact between the tapered valve seat contact surface 304b of the valve body 304 and the peripheral edge of the opening end of the valve hole 305a is further increased. Approaches single-layer contact. As a result, the action of the discharge pressure in the valve hole opening / closing direction on the valve body 304 is further effectively prevented.
Since the communication hole 301d intersects the accommodating hole 301c having a diameter larger than that of the support hole 301b, even if a processing burr generated at the intersecting part between the accommodating hole 301c and the communicating hole 301d remains, the other end of the valve body 304 The operation of inserting a pressure-sensitive rod 304c into the support hole 301b is not hindered. Therefore, the operation of inserting the pressure sensitive rod 304c into the support hole 301b is easier than the capacity control valve of Patent Document 1.
Since the valve hole 305a and the support hole 301b are simultaneously finished using the same tool, the coaxiality of the valve hole 305a and the support hole 301b is improved, and the assemblability of the valve body 304 is improved. Further, by improving the coaxiality of the valve body 304 and the valve hole 305a, the sealing performance of the valve body 304 when the valve seat contact surface 304b, which is a tapered surface, contacts the peripheral edge of the opening end of the valve hole 305a is improved. Leakage during valve closing is reduced.
By finishing the valve hole 305a and the support hole 301b to the same diameter, control characteristics with little influence of the discharge pressure can be obtained.
The valve hole 305a, the support hole 301b, and the valve seat 305b may be finished simultaneously using the same tool. The perpendicularity between the valve hole 305a and the support hole 301b and the valve seat surface is improved, and leakage at the time of valve closing is reduced.

As shown in FIG. 4, the driving means for driving the valve body in the opening / closing direction is displaced by the change in the pressure difference between the discharge chamber 120 and the muffler space 121, which are two pressure monitoring points of the refrigerant circuit, thereby driving the valve body. The discharge capacity control valve 400 constituted by the autonomous control mechanism including the differential pressure detecting member 401 and the external control mechanism that changes the differential pressure control characteristic of the autonomous control mechanism by applying electromagnetic force to the valve body, The techniques described above are applicable.
The discharge capacity control valve 400 can optimally control the pressure difference between the pressure monitoring points according to the external environment.

Since the differential pressure between the discharge pressure and the crank pressure acts on the valve seat forming body 305, as shown in FIG. 5, after the valve seat forming body 305 is press-fitted and fixed to the valve housing 301, the valve seat forming body such as caulking is removed. Preventive measures may be taken. It is particularly suitable when compressing carbon dioxide.

The present invention is not limited to the above-described embodiment, and a discharge capacity control valve in which the valve hole diameter is larger than the support hole diameter and the control suction pressure increases as the discharge pressure increases. The valve hole diameter is smaller than the support hole diameter and the discharge pressure increases. Then, a discharge capacity control valve in which the control suction pressure decreases, a discharge capacity control valve in which the valve seat forming body is subjected to a surface hardening process such as nitriding, a discharge capacity control valve in which the valve body is subjected to a surface hardening process such as nitriding, Discharge capacity control valve for two-position control of open position and closed position, discharge capacity control valve for use in motor-driven variable capacity compressor, discharge capacity control valve for use in variable capacity compressor that compresses CO2 and R152a, etc. Widely available.

It is sectional drawing of the variable capacity | capacitance swash plate type compressor provided with the discharge capacity control valve based on 1st Example of this invention. It is sectional drawing of the discharge capacity | capacitance control valve which concerns on 1st Example of this invention. (A) is a general view, (b) is a partially enlarged view excluding the valve body of (a), and (c) is a partially enlarged view in a valve-closed state. It is a figure which shows the control characteristic type | formula of the discharge capacity | capacitance control valve which concerns on 1st Example of this invention. It is sectional drawing of the discharge capacity | capacitance control valve which concerns on 2nd Example of this invention. It is a partial expanded sectional view of the discharge capacity control valve concerning a 3rd example of the present invention.

Explanation of symbols

100 Variable displacement swash plate compressor 105 Crank chamber 106 Drive shaft 107 Swash plate 117 Piston 119 Suction chamber 120 Discharge chamber 300 Capacity control valve 305 Valve seat forming body

Claims (6)

A valve chamber that communicates with the crank chamber and communicates with the discharge pressure region via the valve hole and the communication hole, a valve body having one end portion disposed in the valve chamber for opening and closing the valve hole, and the other end portion of the valve body A valve housing that has a support hole that slidably supports the valve body and shuts off the other end of the valve body from the discharge pressure region and accommodates the valve body, and driving means that drives the valve body in the valve hole opening and closing direction, The valve hole and the valve seat around the opening of the valve hole are formed in a valve seat forming body that is separate from the valve housing and made of a material having higher hardness than the valve housing, and the valve seat forming body is formed in the valve housing. A discharge capacity control valve for a variable capacity compressor, wherein the communication hole and the valve hole communicate with each other through a housing hole, which is fitted and fixed in a housing hole having a diameter larger than that of the support hole. 2. A discharge capacity control valve for a variable capacity compressor according to claim 1, wherein the valve seat abutting surface of the valve body is a tapered surface and abuts against a peripheral edge of the valve hole opening when the valve is closed. The discharge capacity control valve for a variable capacity compressor according to claim 1 or 2, wherein a connection portion between the valve hole and the valve seat surface is a corner. The discharge capacity control valve for a variable capacity compressor according to any one of claims 1 to 3, further comprising a drop prevention means for preventing the valve seat forming body from falling off. The drive means is connected to the other end of the valve body, and has an autonomous control mechanism having a pressure-sensitive member that is displaced by a change in suction pressure to drive the valve body, and an autonomous control mechanism by applying an electromagnetic force to the valve body. The discharge capacity control valve for a variable capacity compressor according to any one of claims 1 to 4, further comprising an external control mechanism that changes a suction pressure control characteristic. The driving means is connected to the other end of the valve body, and has an autonomous control mechanism having a pressure-sensitive member that is displaced by a change in pressure difference between two pressure monitoring points of the refrigerant circuit to drive the valve body, The discharge capacity of the variable capacity compressor according to any one of claims 1 to 4, further comprising an external control mechanism that changes a differential pressure control characteristic of the autonomous control mechanism by applying a force. Control valve.

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