JP2001133081A - Expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expansion valve for preventing cutting dust that causes the leakage of a refrigerant from being generated when screwing another member to a body block. SOLUTION: A spring support member 18 for receiving the fixed end side of a compression coil spring 17 is formed by a synthetic resin and is screwed and fitted into a body block 11. Also, a power element 30 is screwed and fitted to the body block 11, and at least one of screw parts 25a and 25b at the side of the power element 30 and the side of the body block 11 is formed by rolling machining.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expansion valve for adiabatically expanding a refrigerant while controlling the flow rate of the refrigerant sent to an evaporator in a refrigeration cycle.

[0002]

2. Description of the Related Art There are various types of expansion valves, and a valve is provided in a main body block facing a valve seat hole formed by narrowing the middle of a high-pressure refrigerant passage through which a high-pressure refrigerant sent to an evaporator passes. 2. Description of the Related Art An expansion valve in which a valve body is arranged and a valve body is opened and closed according to the temperature and pressure of a low-pressure refrigerant sent from an evaporator is widely used.

[0003] In such an expansion valve, a rod is inserted between a power element that operates according to the temperature and pressure of the low-pressure refrigerant sent from the evaporator and a valve body so as to be movable back and forth in the axial direction. The valve element is urged by a compression coil spring from a direction opposite to the rod, and the power element causes the valve element to open and close via the rod.

A screw-bar-shaped spring receiving member for receiving the fixed end side of such a compression coil spring is screwed and attached to the main body block, and the amount of screwing of the spring receiving member is adjusted so that it can be used during assembly. The state of the compression coil spring can be adjusted. An O-ring for sealing is mounted on the spring receiving member in order to prevent the refrigerant from leaking from that portion.

[0005]

In the conventional expansion valve, the main body block is generally formed of an aluminum alloy, and the spring receiving member is formed of a metal material such as brass.

Therefore, when the screw-bar-shaped spring receiving member is screwed into the main body block as described above, the screw on the main body block side is cut off at that time, and the cutting powder damages the O-ring for sealing, thereby causing refrigerant leakage. Occurred in some cases.

In the power element, a male screw portion formed in a stainless steel housing is screwed into a female screw portion formed in the main body block, and is attached to the main body block. Occasionally, this could cause refrigerant leakage.

Accordingly, an object of the present invention is to provide an expansion valve which does not generate chips which cause refrigerant leakage when another member is screwed into the main body block.

[0009]

In order to achieve the above object, an expansion valve according to the present invention is provided in a valve seat hole formed by narrowing the middle of a high-pressure refrigerant flow path through which a high-pressure refrigerant sent to an evaporator passes. A valve element is disposed in the main body block to face each other, and a rod disposed so as to be able to advance and retreat in the axial direction is connected to a power element and a valve element that operate in accordance with the temperature and pressure of the low-pressure refrigerant sent from the evaporator. A spring receiving member for receiving the fixed end side of the compression coil spring is formed of synthetic resin in the expansion valve in which the valve element is biased by a compression coil spring from a direction opposite to the power element, and the body is formed of a synthetic resin. It is screwed to.

[0010] The tip of the thread of the thread of the spring receiving member may be formed into a smooth curved surface, or may be elastically pressed and shrunk against the thread of the body block. They may be screwed together.
A hole for engaging the rotary tool with the outer surface of the spring receiving member may be formed in a star-shaped cross section.

In the expansion valve according to the present invention, a valve body is disposed in a main body block so as to face a valve seat hole formed by narrowing the middle of a high-pressure refrigerant flow path through which a high-pressure refrigerant sent to an evaporator passes. , A rod disposed so as to be able to advance and retreat in the axial direction is sandwiched between a power element and a valve element that operate in accordance with the temperature and pressure of the low-pressure refrigerant sent from the evaporator, and the valve element is connected to the power element. In the expansion valve urged by the compression coil spring from the opposite direction, the power element is screwed into the main body block, and at least one of the threaded portions on the power element side and the main body block side is formed by rolling. The main body block may be formed of JIS A6000-based aluminum alloy material.

[0012]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an expansion valve according to an embodiment of the present invention. In the drawing, 1 is an evaporator, 2 is a compressor, 3 is a condenser, 4 is a liquid receiver connected to the outlet side of the condenser 3 and containing a high-pressure liquid refrigerant, and 10 is an expansion valve. These components form a refrigeration cycle, and are used, for example, for indoor cooling devices (car air conditioners) of automobiles.

The main body block 11 of the expansion valve 10 has a low-pressure refrigerant passage 12 through which low-temperature and low-pressure refrigerant gas sent from the evaporator 1 to the compressor 2 passes, and a high-temperature and high-pressure refrigerant liquid sent to the evaporator 1. And a high-pressure refrigerant channel 13 for adiabatic expansion through the passage.

The main body block 11 is made of a material having excellent corrosion resistance such as, for example, JIS A6000-based aluminum alloy material. No surface treatment is required, resulting in low cost.

The low-pressure refrigerant passage 12 has an inlet end connected to the outlet of the evaporator 1 and an outlet connected to the inlet of the compressor 2. The high-pressure refrigerant flow path 13 has an inlet-side end connected to the outlet of the liquid receiver 4, and an outlet connected to the inlet of the evaporator 1.

The low-pressure refrigerant flow path 12 and the high-pressure refrigerant flow path 13 are formed parallel to each other, and a through hole 14 formed in the main body block 11 perpendicularly to the low-pressure refrigerant flow path 12 and the high-pressure refrigerant flow path It passes through between the road 13. A power element 30 is attached to an opening formed in the same direction as the through hole 14 so as to pass outward from the low-pressure refrigerant flow path 12.

In the middle of the high-pressure refrigerant flow passage 13, a valve seat hole 15 is formed at the center where the flow passage area is narrowed in the middle, and the valve seat hole 15 is spherically opposed to the valve seat hole 15 from the upstream side. Is disposed.

As a result, the narrowest part of the gap between the valve body 16 and the inlet of the valve seat hole 15 becomes the throttle of the high-pressure refrigerant flow path 13, from which the downstream flow reaching the evaporator 1 reaches. In the passage, the high-pressure refrigerant adiabatically expands.

The valve body 16 is formed of a metal such as stainless steel, for example, and the open end of the valve seat hole 15 facing the valve body 16 is formed into a shape that is tapered and chamfered and spreads outward. I have.

The valve body 16 is a tapered compression coil spring 1 whose winding diameter gradually decreases toward the valve body 16 side.
7 urges in a direction approaching the valve seat hole 15 (that is, a closing direction).

The valve body 16 is directly fixed to the smaller end of the compression coil spring 17 by welding or the like (adhesion, soldering or the like). By forming the compression coil spring 17 in a tapered shape, the valve body 16 can be directly fixed to the end thereof.

The hole 19 in which the compression coil spring 17 is disposed is formed in the main body block 11 in the same direction as the valve seat hole 15 (and, therefore, in the direction perpendicular to the high-pressure refrigerant flow path 13). It is open to.

A spring receiving member 18 for receiving the fixed end side of the compression coil spring 17 is screwed into the hole 19 from the open end side so that the spring force of the compression coil spring 17 is appropriate during assembly work. The fixing position of the spring receiving member 18 is adjusted by adjusting the screwing amount so as to obtain the value.

A male screw portion 22a is formed at an outer half of the outer peripheral surface of the spring receiving member 18, and a female screw portion 22b formed at the entrance of the hole 19 on the body block 11 side.
And a half of the outer peripheral surface of the spring receiving member 18 is fitted to the inner peripheral surface of the hole 19.

An O-ring 21 for sealing is mounted in a circumferential groove formed on the outer peripheral surface of the spring receiving member 18 on the fitting surface, and refrigerant leakage from the portion where the spring receiving member 18 is mounted is prevented. I'm preventing.

The spring receiving member 18 is formed of a synthetic resin. Therefore, the spring receiving member 1
8 male screw part 22a to the female screw part 2 on the main body block 11 side.
At the time of the assembling work in which the spring receiving member 18 is screwed into the main body block 2b and attached to the main body block 11, chips as in the related art are not generated, and refrigerant leakage hardly occurs.

As the material of the spring receiving member 18, for example, polyphenyl sulfide or polyphthalamide is used, which is excellent in strength, and as shown in FIG. By forming the tip portion of the thread of the male screw portion 22a into a smooth curved surface, there is an effect of suppressing generation of chips on the spring receiving member 18 side.

As shown in FIG.
If the thread of the male screw portion 22a of the spring receiving member 18 is formed to be larger than the original width and a slit is formed at the center, the female screw on the main body block 11 side in a state where the male screw portion 22a is elastically compressed. Since the screw is engaged with the portion 22b and the force of the spring back acts as a lock, the fixing position of the spring receiving member 18 does not change without applying a fixing agent such as a screw lock.

As shown in FIG. 1, a tool engaging hole 18 for engaging a tool for rotating the spring receiving member 18 around an axis is formed in an outer end surface of the spring receiving member 18.
Although a is formed concavely, its cross-sectional shape is formed in a star shape as shown in FIG.

Therefore, even if the spring receiving member 18 is made of synthetic resin, the corner of the tool engaging hole 18a is hardly rounded at the time of work and the tool is unlikely to idle. It should be noted that the number of mountains does not need to be five even when it is referred to as a “star”, and may be, for example, about three to eight.

When molding such a spring receiving member 18, it is preferable to arrange the gate into which the resin flows, at the center axis position, as schematically shown in FIG. By doing so, welding cannot be performed, so that refrigerant leakage hardly occurs. The same effect can be obtained even if the gate is a center pin gate, a cylindrical film gate, or the like.

As shown in FIG. 7 and FIG.
If the spring receiving member 18 is molded by double molding divided by the ring mounting groove 18C as a boundary, a parting line does not appear in the O-ring mounting groove 18C, so that the sealing effect by the O-ring 21 is more reliably achieved. Become.

Returning to FIG. 1, the rod 20 inserted into the through hole 14 is provided slidably in the axial direction.
The upper end reaches the vicinity of the back surface of the power element 30, and the middle part vertically crosses the low-pressure refrigerant flow path 12 and has a through hole 14.
, And the lower end passes through the valve seat hole 15 and abuts on the head of the valve body 16. The rod 20 is formed to be thinner than the valve seat hole 15 so that a space between the rod 20 and the wall surface of the valve seat hole 15 serves as a coolant flow path.

The power element 30 is surrounded by a housing 31 made of a highly rigid stainless steel plate.
The outer half of the airtight chamber 30 is hermetically surrounded by a housing 31 and a diaphragm 32 made of a flexible thin metal plate (for example, a stainless steel plate having a thickness of 0.1 mm).
a.

The refrigerant passages 12 and 13 are provided in the airtight chamber 30a.
A gas in a saturated vapor state having the same or similar properties as the refrigerant flowing therein is filled therein, and the gas filling inlet is closed by welding a stopper 34.

A large dish-shaped diaphragm receiving board 33 is arranged facing the rear face of the diaphragm 32, and the end of the rod 20 is in contact with the rear face of the diaphragm receiving board 33. Therefore, the rod 20 is disposed so as to be sandwiched between the diaphragm receiving plate 33 and the valve body 16 so as to be able to advance and retreat in the axial direction.

As shown in the perspective view of FIG. 2, the diaphragm receiving board 33 has a dish shape in which three leg portions 33a are formed by bending, and is formed by pressing a plate material.

A slope 36 is formed at the center of the back surface of the diaphragm receiving plate 33, and the leg-like portion 33a has a function of loosely fitting the inner peripheral surface of the housing 31 to stabilize the posture of the diaphragm receiving plate 33. are doing. In addition, the leg 33
The portion cut out by bending a is the refrigerant passage 40.

The through hole 14 formed in the main body block 11
An intermediate portion of the rod 20 is fitted to the portion, and a projection 23 is protruded from the rod 20 at a position slightly away from the low-pressure refrigerant flow path side opening 14 a of the through hole 14.

Since the projections 23 are formed as described above, the rod 20 does not enter the through hole 14 any more, so that the rod 20 can be held in a stable state during assembly. The low pressure refrigerant flow path side opening 14a of the through hole 14 is chamfered in a tapered shape.

A male screw portion 25a is formed on an outer peripheral surface of the housing 31 formed so as to entirely surround the power element 30 near an end near the main body block 11, and the male screw portion 25a is formed of an aluminum alloy. The power element 30 is attached to the main body block 11 by being screwed into a female screw portion 25b formed on the main body block 11 made of aluminum. 26 is a seal member.

Both the male screw portion 25a and the female screw portion 25b of the screwed portion are formed not by cutting but by rolling. Therefore, the generation of burrs at the time of manufacturing and the generation of cutting chips at the time of screwing work are small, and it is hard to cause refrigerant leakage. Further, it is even better if the tip of the screw thread is curved.

A rod receiver 37 into which the rod 20 is slidably fitted in the vicinity of the end is formed at the center of the portion of the housing 31 facing the low-pressure refrigerant flow path 12. The sticking is regulated and the generation of noise is suppressed.

The low-pressure refrigerant flow path 12 around the rod receiver 37
A refrigerant passage hole 38 for guiding a small amount of refrigerant passing through the low-pressure refrigerant flow path 12 into the power element 30 is formed in the housing 31 at a portion facing the low-pressure refrigerant flow path 12, and passes through the low-pressure refrigerant flow path 12. The change in the state of the temperature and the pressure of the refrigerant is delayed and transmitted slowly to the back surface of the diaphragm 32, so that the expansion valve 10 does not suddenly change its operation.

In the expansion valve configured as described above,
When the temperature of the low-pressure refrigerant flowing in the low-pressure refrigerant flow path 12 decreases, the temperature of the diaphragm 32 decreases, and the saturated vapor gas in the hermetic chamber 30 a of the power element 30 condenses on the inner surface of the diaphragm 32.

Then, the pressure in the hermetic chamber 30a decreases and the diaphragm 32 is displaced, so that the rod 20 is pushed and moved by the compression coil spring 17, and as a result, the valve body 16 moves to the valve seat hole 15 side. As a result, the flow path area of the high-pressure refrigerant is reduced, and the flow rate of the refrigerant sent to the evaporator 1 is reduced.

When the temperature of the low-pressure refrigerant flowing in the low-pressure refrigerant passage 12 rises, the valve body 16 is moved in a direction away from the valve seat hole 15 by the rod 20 pushed by the power element 30 by the reverse operation. As a result, the flow path area of the high-pressure refrigerant increases, and the flow rate of the high-pressure refrigerant sent to the evaporator 1 increases.

The contact surface of the diaphragm receiving plate 33 with which the rod 20 abuts is a slope 36, so that the power element 30 and the compression coil spring 1
The force applied to the rod 20 from the position 7 also acts as a couple that tries to rotate the rod 20 in a direction that changes the direction of the axis.

As a result, when the rod 20 advances and retreats, a considerably large frictional resistance is generated between the rod 20 and the inner wall of the through-hole 14. Therefore, when the pressure of the high-pressure refrigerant in the high-pressure refrigerant flow path 13 changes, Since the operation of the rod 20 (that is, the opening / closing operation of the valve element 16) does not react sensitively thereto, the operation of the valve element 16 does not react sensitively to the pressure fluctuation of the high-pressure refrigerant even if there is a pressure fluctuation. stable.

[0050]

According to the present invention, the spring receiving member for receiving the fixed end side of the compression coil spring for urging the valve body against the power element is formed of synthetic resin, so that the spring receiving member is formed on the main body block. When screwing is mounted, chips which cause refrigerant leakage are not generated.

Further, by forming at least one of the power element and the threaded portion of the main body block by rolling, chips are generated which may cause refrigerant leakage when the power element is screwed into the main body block. do not do.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an expansion valve according to an embodiment of the present invention.

FIG. 2 is a perspective view of a diaphragm receiver of the expansion valve according to the embodiment of the present invention.

FIG. 3 is a partially enlarged cross-sectional view of a threaded portion between a main body block and a spring receiving member according to the embodiment of the present invention.

FIG. 4 is a partially enlarged cross-sectional view of another example of a threaded portion between the main body block and the spring receiving member according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view of a tool engagement hole formed in a spring receiving member according to the embodiment of the present invention.

FIG. 6 is a cross-sectional view showing an example of a state in which the spring receiving member according to the embodiment of the present invention is molded.

FIG. 7 is a cross-sectional view illustrating an example of a case where the spring receiving member according to the embodiment of the present invention is formed by double molding.

FIG. 8 is a cross-sectional view showing another example in which the spring receiving member according to the embodiment of the present invention is formed by double molding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Main body block 12 Low-pressure refrigerant flow path 13 High-pressure refrigerant flow path 16 Valve element 17 Compression coil spring 18 Spring receiving member 18a Tool engagement hole 19 hole 20 Rod 22a Male screw part 22b Female screw part 25a Male screw part 25b Female screw part 30 Power element 31 housing

Claims (6)

[Claims] 1. A valve body is disposed in a main body block to face a valve seat hole formed by narrowing the middle of a high-pressure refrigerant flow path through which a high-pressure refrigerant sent to an evaporator passes. The arranged rod is interposed between the power element and the valve element that operate in accordance with the temperature and pressure of the low-pressure refrigerant sent from the evaporator, and the valve element is placed opposite to the power element. An expansion valve biased by a compression coil spring from a direction, wherein a spring receiving member for receiving a fixed end side of the compression coil spring is formed of synthetic resin and screwed to the main body block. valve. 2. The expansion valve according to claim 1, wherein a tip portion of a thread of the thread portion of the spring receiving member is formed into a smooth curved surface. 3. The expansion valve according to claim 1, wherein the thread of the thread portion of the spring receiving member is screwed together with the thread portion of the main body block while being elastically pressed and contracted. 4. The expansion valve according to claim 1, wherein a hole for engaging a rotary tool with an outer surface of the spring receiving member is formed in a star-shaped cross section. 5. A valve body is disposed in a main body block so as to face a valve seat hole formed by narrowing the middle of a high-pressure refrigerant passage through which a high-pressure refrigerant sent to an evaporator passes, and is capable of moving back and forth in an axial direction. The arranged rod is interposed between the power element and the valve element that operate in accordance with the temperature and pressure of the low-pressure refrigerant sent from the evaporator, and the valve element is placed opposite to the power element. In the expansion valve urged by a compression coil spring from the direction, the power element is screwed to the main body block, and at least one of the power element side and the threaded portion on the main body block side is formed by rolling. An expansion valve characterized by being made. 6. The JIS A6000 body block.
2. The method according to claim 1, wherein the material is made of a series aluminum alloy material.
6. The expansion valve according to any one of items 5 to 5.