JP2002115938A - Expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expansion valve which causes no bypass leakage of a refrigerant from a through-hole with a rod penetrating thereinto and has no need of a high working accuracy for the through-hole. SOLUTION: A rod 15 pierces a through-hole 16 of a body block 2, an O-ring 18 is disposed in the through-hole 16 to perfectly prevent a bypass leakage of a refrigerant from the through-hole 16 which is sealed with the O-ring 18, resulting in a larger worked hole than a hole for inserting the rod 15 only. This eliminates the need of a high working accuracy at a high working cost. The top end of a cylindrical part 17a of a holder 17 for holding the end of the rod 15 at the diaphragm side regulates the O-ring 18 shifting due to a slide motion in the axial direction of the rod 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expansion valve.
A temperature-type expansion valve used in a refrigeration cycle using a variable capacity compressor having an external control valve, which controls the flow rate of the refrigerant so that the refrigerant at the evaporator outlet has a predetermined degree of superheat while providing a low-pressure refrigerant. About.

[0002]

2. Description of the Related Art In an air conditioner for a vehicle, a compressor compresses a refrigerant gas to a high temperature and a high pressure, cools it with a condenser to condense and liquefy it, and separates it into a gas and a liquid with a receiver / dryer. The liquid refrigerant is decompressed and expanded by an expansion valve to be a low-temperature and low-pressure refrigerant, which is evaporated by an evaporator and returned to the compressor.

The expansion valve supplies high-temperature, high-pressure liquid refrigerant from a receiver / dryer to a low-temperature, low-pressure refrigerant by passing it through a valve constituting an orifice, and supplies the refrigerant to the evaporator at the same time. And controls the flow rate of the refrigerant passing through the valve, thereby controlling the amount of the refrigerant in accordance with fluctuations in the cooling load and fluctuations in the number of revolutions of the compressor.

FIG. 2 is a sectional view showing a configuration example of a conventional expansion valve. The expansion valve 1 is provided on the side of the main body block 2 with a refrigerant pipe connection hole 3 for connecting a high-pressure refrigerant pipe to which a high-temperature and high-pressure refrigerant is supplied from a receiver / dryer. A refrigerant pipe connection hole 4 for connecting a low-pressure refrigerant pipe for supplying low-temperature and low-pressure refrigerant to the evaporator, a refrigerant pipe connection hole 5 for connecting a refrigerant pipe from the evaporator outlet, and a refrigerant for connecting a refrigerant pipe to the compressor. And a conduit connection hole 6.

[0005] A valve seat 7 is formed integrally with the main body block 2 in a fluid passage between the refrigerant pipe connection hole 3 and the refrigerant pipe connection hole 4, and a valve is provided upstream of the valve seat 7. A ball-shaped valve element 8 is arranged facing the seat 7. A compression coil spring 9 for urging the valve body 8 to sit on the valve seat 7 is disposed in the fluid passage communicating with the refrigerant pipe connection hole 3. The compression coil spring 9 is received by a spring receiver 10 screwed to the lower end of the main body block 2.

A power element is provided at the upper end of the main body block 2. The power element includes an upper housing 11, a lower housing 12, a diaphragm 13 that partitions a space surrounded by the upper housing 11, a lower housing 12, and a diaphragm receiving board 14 disposed on the lower surface of the diaphragm 13. A rod 15 for transmitting the displacement of the diaphragm 13 to the valve body 8 is disposed below the diaphragm receiving board 14 through a through hole 16 of the main body block 2. The upper portion of the rod 15 is held by a holding member 17 arranged across a fluid passage communicating with the refrigerant pipe connection holes 5 and 6. The holding member 17
Has a cross-shaped cross section, and the portion other than the cross shape serves as a fluid passage. The lower chamber of the power element partitioned by the diaphragm 13 and the fluid in the refrigerant pipe connection holes 5 and 6 have a fluid passage. It is designed to communicate with the passage.

Here, the through hole 16 formed in the center of the main body block 2 has a small clearance between the rod 15 and a part of the refrigerant flowing into the evaporator. The amount of refrigerant leaking from the evaporator to the fluid passage returning from the evaporator through the clearance portion between the two is suppressed to a low level.

[0008]

However, the through-hole 16 is a hole having a small diameter in the inner part of the main body block 2 although a considerable processing accuracy is required to suppress the bypass amount of the refrigerant. Therefore, there is a problem that it is very difficult to obtain a high processing accuracy, and the surface is formed with a slanted hole or the inner wall surface is rough and has poor surface accuracy.

Further, when the processing accuracy of the through hole 16 is reduced, the sliding frictional force with the rod 15 is increased, so that the operation becomes unstable and smooth valve opening control cannot be performed. In the worst case, a load is applied. If galling occurs,
There has been a problem that the rod 15 does not move, the valve remains fully open or fully closed, and the expansion valve stops functioning.

The present invention has been made in view of the above points, and there is no expansion valve which leaks refrigerant by-pass through a through-hole through which a rod is inserted and which does not require high processing accuracy of the through-hole. The purpose is to provide.

[0011]

According to the present invention, in order to solve the above-mentioned problems, a valve constituting a variable orifice, a diaphragm which generates displacement in accordance with pressure and temperature of a refrigerant, and
A rod disposed through a through hole of the main body block to transmit a displacement of the diaphragm to a valve body of the valve to control an opening of the valve, and a holding member for holding an end of the rod on the diaphragm side And a seal member disposed in the through hole to seal a space between the rod and the rod, wherein the movement of the seal member accompanying the axial movement of the rod is maintained. An expansion valve is provided, wherein the member is regulated at an end of a cylindrical portion extending along the rod.

According to such an expansion valve, since the space between the expansion valve and the rod is sealed by the seal member, it is possible to completely prevent the refrigerant from leaking through the through-hole in the through-hole, and the through-hole receives the seal member. Since it is a hole having a size and the rod is supported by the seal member, high processing cost and high processing accuracy are not required for the hole processing. In addition, since the movement of the seal member is regulated at the end of the cylindrical portion of the holding member, the seal member does not jump out of the through-hole due to the axial movement of the rod.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view showing a configuration example of an expansion valve according to the present invention. In FIG. 1, the same components as those of the conventional expansion valve are denoted by the same reference numerals.

In the expansion valve 1, a refrigerant pipe connection hole 3 provided on a side of the main body block 2 is provided with a receiver /
The refrigerant pipe connection hole 4 is connected to a high-pressure refrigerant pipe to which a high-temperature and high-pressure refrigerant is supplied from a dryer. The refrigerant pipe connection hole 5 is connected to the refrigerant pipe from the evaporator outlet, the refrigerant pipe connection hole 6 is connected to the refrigerant pipe leading to the compressor, and the arrow shown in the drawing indicates the flow direction of the refrigerant. .

A valve seat 7 is formed integrally with the main body block 2 in a fluid passage communicating from the refrigerant pipe connection hole 3 to the refrigerant pipe connection hole 4, and a valve seat 7 is provided upstream of the valve seat 7. And a ball-shaped valve element 8 is arranged opposite to. As a result, the gap between the valve seat 7 and the valve element 8 constitutes a variable orifice for restricting the high-pressure refrigerant, and the high-pressure refrigerant adiabatically expands in the downstream flow path from there toward the refrigerant pipe connection hole 4. ing. In the fluid passage on the refrigerant pipe connection hole 3 side, a valve element 8 is provided.
A compression coil spring 9 for urging the valve to be seated on the valve seat 7 is arranged. The compression coil spring 9 is received by a spring receiver 10.

A power element is provided at the upper end of the main body block 2. The power element includes a diaphragm 1 made of a thick metal upper housing 11 and a lower housing 12 and a flexible thin metal plate arranged to partition a space surrounded by the upper housing 11 and the lower housing 12.
3 and a diaphragm receiving board 14 arranged on the lower surface of the diaphragm 13.

Below the diaphragm receiving board 14, a rod 15 for transmitting the displacement of the diaphragm 13 to the valve body 8 is arranged. The rod 15 passes through a through hole 16 formed in the main body block 2.

The through hole 16 has a large diameter portion 16 at its upper part.
a, has a small diameter portion 16b in the lower portion, and the upper open end of the large diameter portion 16a is formed in a tapered chamfered shape. The large diameter portion 16a of the through hole 16 has a rod 15
An O-ring 18 is disposed as a seal member for completely sealing between the through hole 16 and the through hole 16, thereby completely preventing refrigerant from leaking through the through hole 16.

The holding member 17 holding the upper end of the rod 15 has a cylindrical portion 17a that hangs across a fluid passage communicating with the refrigerant pipe connection holes 5 and 6, and has a lower end. The part is fitted into the large diameter part 16a of the through hole 16,
The lower end surface restricts the movement of the O-ring 18 toward the upper opening end of the through hole 16.

Further, since the upper portion of the rod 15 is held by the holding member 17 and the lower portion is held by the O-ring 18, excessive sliding friction between the rod 15 and the through hole 16 at the time of its axial movement is obtained. This is a structure in which no galling occurs with the through-hole 16.
Therefore, for example, JIS A6
Even if a material such as a 000-series aluminum alloy material that is apt to galling is used, the rod 15 does not stick and move.

The upper end of the rod 15 is in contact with the lower surface of the diaphragm receiving board 14, and the contact surface is inclined with respect to a plane perpendicular to the axis of the rod 15, and the axis of the diaphragm 13 is Movement of the rod 15
And a lateral load. As a result, when the movement of the diaphragm 13 is transmitted to the rod 15, a lateral force component acts on the rod 15, and when the pressure of the high-pressure refrigerant in the refrigerant pipe connection hole 3 fluctuates, the operation of the rod 15 reacts sensitively. The vibration in the longitudinal direction of the rod 15 is suppressed so as not to cause the vibration.

In the expansion valve 1 having the above configuration, when the temperature of the refrigerant returning from the evaporator to the refrigerant pipe connection hole 5 decreases, the temperature of the diaphragm 13 decreases, and the saturated steam gas in the power element is removed from the diaphragm 13. Condenses on the surface. As a result, the pressure in the power element is reduced and the diaphragm 13 is displaced upward, so that the rod 15 is pushed by the compression coil spring 9 and moves upward. As a result, the valve element 8 moves to the valve seat 7 side, so that the flow area of the high-pressure refrigerant decreases, and the flow rate of the refrigerant sent to the evaporator decreases.

When the temperature of the refrigerant from the evaporator rises, the pressure inside the power element rises,
The rod 15 is pushed down against the urging force of the compression coil spring 9. Therefore, the valve element 8 moves in the direction away from the valve seat 7, the flow area of the high-pressure refrigerant increases, and the flow rate of the refrigerant sent to the evaporator increases.

The O-ring 18 also moves with the movement of the rod 15 in the axial direction. The downward movement of the O-ring 18 is restricted by a step at the boundary between the large diameter portion 16a and the small diameter portion 16b. The upward movement is performed by the holding member 1.
7 is regulated by the cylindrical portion 17a.

[0025]

As described above, according to the present invention, the seal member is disposed in the through hole of the main body block in which the rod is inserted, and the holding member holding the diaphragm side end of the rod is in the axial direction of the rod. The configuration is such that the movement of the seal member is prevented. Accordingly, a large diameter is required for the through-hole in which the seal member is arranged, so that high processing accuracy is not required, and therefore, the processing cost can be reduced.

Further, in the conventional clearance seal, a part of the refrigerant leaks through the clearance between the rod and the through hole. However, the use of the seal member completely eliminates the refrigerant leakage. Can be prevented.

Further, since the rod is supported at two points, that is, the holding member and the seal member disposed in the through hole, the resistance at the time of sliding of the rod is small, and the smooth movement of the valve body can be continued.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration example of an expansion valve according to the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration example of a conventional expansion valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Expansion valve 2 Body block 3,4,5,6 Refrigerant line connection hole 7 Valve seat 8 Valve 9 Compression coil spring 10 Spring receiver 11 Upper housing 12 Lower housing 13 Diaphragm 14 Diaphragm receiving board 15 Rod 16 Through hole 16a Large Diameter part 16b Small diameter part 17 Holding member 17a Cylindrical part 18 O-ring

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Isao Sendo, Inventor 1211-4, Nukuda-cho, Hachioji-shi, Tokyo F-term in TDK Corporation (reference) 3H057 AA04 BB37 BB38 CC06 DD04 DD05 EE01 FD19 HH16 HH18 3H066 AA01 BA18 BA19 DA02

Claims (3)

[Claims] 1. A valve constituting a variable orifice, a diaphragm for producing displacement according to pressure and temperature of a refrigerant,
A rod disposed through a through hole of the main body block to transmit a displacement of the diaphragm to a valve body of the valve to control an opening of the valve, and a holding member for holding an end of the rod on the diaphragm side And a seal member disposed in the through hole to seal a space between the rod and the rod, wherein the movement of the seal member accompanying the axial movement of the rod is held. An expansion valve, wherein a member is regulated at an end of a cylindrical portion extending along the rod. 2. The through hole has a large-diameter portion on the diaphragm side and a small-diameter portion on the valve side, wherein the seal member is disposed in the large-diameter portion, and a cylinder of the holding member is provided. The expansion valve according to claim 1, wherein an end of the shape is fitted. 3. The expansion valve according to claim 2, wherein the large-diameter portion is formed in a shape in which an opening end thereof is tapered.