JP2001133082A - Expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expansion valve that can be easily mounted by appropriately screwing a power element unit to a body unit. SOLUTION: A guide part 25c for regulating the loose fitting to a target screw part and the screwing while both screw parts 25a and 25b are inclined is formed, at least, at one of the screw end part of the side of the power element 30 and that of the body block side being screwed first when the screw part 25a of the power element unit 30 is screwed into the screw part 25b of a body block 11.

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. An expansion valve in which a body is arranged and a valve element is driven to open and close by a power element unit corresponding to the temperature and pressure of the low-pressure refrigerant sent from the evaporator is widely used. Generally, it is screwed and attached to the main body block.

[0003]

However, since the length of the screw portion for attaching the power element unit to the main body block is shorter than the diameter thereof, inclination occurs when the screwing operation is performed. Easy to do.

[0004] For this reason, the power element unit is screwed in a tilted state, and the screw on the main body block is damaged, so that a trouble that the main body block becomes unusable is likely to occur.

Accordingly, an object of the present invention is to provide an expansion valve in which a power element unit is easily screwed into a main unit to be easily mounted.

[0006]

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 arranged in the main body block to face it, and a power element unit for opening and closing the valve element in accordance with the temperature and pressure of the low-pressure refrigerant sent from the evaporator is screwed into the main body block to be mounted. In the valve,
When the screw part of the power element unit is screwed into the screw part of the main body block, at least one of the screw end part on the power element unit side and the screw end part on the main body block side that screw first And a guide portion for restricting loosely fitting and screwing together in a state where both screw portions are inclined.

[0007]

Embodiments of the present invention will be described with reference to the drawings. FIG. 3 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 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 in parallel with 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 is formed. It passes through between the road 13. A power element unit 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 element 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. In the passage, the high-pressure refrigerant adiabatically expands.

The valve body 16 is made of, for example, a metal such as stainless steel, 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 urged by a compression coil spring 17 in a direction approaching the valve seat hole 15 (ie, in a closing direction). The valve body 16 is directly fixed to an end of the compression coil spring 17 having a smaller diameter by welding or the like (adhesion, soldering or the like).

The hole 19 in which the compression coil spring 17 is arranged 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). Missing.

In the hole 19, a spring receiver 18 for receiving the base end side of the compression coil spring 17 is press-fitted and fixed from the outside. Since there is no screw portion, there is no generation of cutting chips due to screwing.

The rod 20 inserted into the through hole 14
It is slidably provided in the axial direction, the upper end reaches the inside of the power element unit 30, the middle part vertically intersects the low-pressure refrigerant flow path 12 and fits in the through hole 14, and the lower end has a valve It passes through the seat hole 15 and contacts 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.

A conical recess 22 having a V-shaped cross section is formed on the end face of the rod 20 which comes into contact with the valve body 16. As a result, the valve element 16 is lightly fitted into the end face of the rod 20, so that the valve element 16 does not rattle in the lateral direction, and therefore the vibration caused by the valve element 16 vibrating in the lateral direction. There is no sound.

The power element unit 30 is surrounded by a housing 31 made of a highly rigid stainless steel plate, and a half of the housing 31 is formed of a housing 31 and a flexible thin metal plate (for example, a stainless steel plate having a thickness of 0.1 mm). ) Is hermetically sealed by a diaphragm 32 made of
0a.

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 hole is closed by welding a stainless steel stopper 34.

A large dish-shaped diaphragm receiving board 33 is disposed 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. 4, the diaphragm receiving board 33 has a dish shape in which three leg portions 33a are formed by bending, and is formed by pressing from a stainless steel 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 to 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. The projection 23 is formed by crushing the rod 20 from the side.

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 stainless steel housing 31 formed so as to entirely surround the power element unit 30
Is formed in a tubular shape near the end near the main body block 11, and a male screw portion 25a is formed on the outer peripheral surface thereof.

The male screw portion 25a is formed on the main body block 11 made of aluminum alloy.
b, and the power element unit 30 is attached to the main body block 11. 26 is a seal member.

FIG. 1 shows, on an enlarged scale, a portion which firstly engages when the male screw portion 25a of the housing 31 is screwed into the female screw portion 25b of the main body block 11 during assembly. The end of the screw portion 25a is cut into a cylindrical shape that fits loosely with the inner diameter of the female screw portion 25b of the main body block 11, thereby forming a guide portion 25c.

As a result, the male screw portion 25 of the housing 31
When a is screwed into the female screw portion 25b of the main body block 11, the guide portion 25c of the housing 31 is first inserted into the female screw portion 25b of the main body block 11, and as a result, the male screw portion 25a and the female screw portion The two screw portions 25a and 25b are guided so as to prevent the screw portion 25b from being inclined and screwed together.

Therefore, the power element unit 3
There is very little possibility that the screw will be screwed into the main body block 11 in a state where 0 is inclined, so that there is no trouble that the screw portion is damaged at the time of the screwing operation and the so-called screw is lost.

Note that, as shown in FIG.
c so that the female thread portion 25 of the main body block 11 is loosely fitted to the outer diameter of the male thread portion 25a of the housing 31.
The guide portion 25c may be formed on both the main body block 11 and the housing 31 at the end side of b.

Returning to FIG. 3, a rod receiver 37 into which the rod 20 is slidably fitted near the end is formed at the center of the portion of the housing 31 facing the low-pressure refrigerant flow path 12, and As a result, rattling of the rod 20 is restricted, 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 channel 12 into the power element unit 30 is formed in the housing 31.
Since the change in the state of the temperature and pressure of the refrigerant passing through the low-pressure refrigerant flow path 12 is delayed and transmitted slowly to the back surface of the diaphragm 32, the operation of the expansion valve 10 does not suddenly change.

In the expansion valve configured as described above,
When the temperature of the low-pressure refrigerant flowing in the low-pressure refrigerant channel 12 decreases, the temperature of the diaphragm 32 decreases, and the saturated vapor gas in the hermetic chamber 30 a of the power element unit 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 by the compression coil spring 17 and moves. 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 flow path 12 rises, the rod 20 pushed by the power element unit 30 causes the valve 16
Is moved away from the valve seat hole 15, the flow area of the high-pressure refrigerant is increased, and the flow rate of the high-pressure refrigerant sent to the evaporator 1 is increased.

Since the abutment surface of the diaphragm receiving plate 33 on which the rod 20 abuts is the inclined surface 36, the force received by the rod 20 from the power element unit 30 and the compression coil spring 17 is limited by the direction of the axis. Also acts as a couple trying to rotate the rod 20 in a direction that changes

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 high-pressure refrigerant in the high-pressure refrigerant flow path 13 fluctuates in pressure, 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.

[0039]

According to the present invention, when the screw portion of the power element unit is screwed into the screw portion of the main body block, the screw end portion on the power element unit side and the screw end portion on the main body block side which are screwed together first. At least one of
By forming a guide part that loosely fits into the thread part of the other party and regulates that both thread parts are inclined and screwed together, when the thread part of the power element unit is screwed into the thread part of the main body block The power element unit is correctly screwed into the main unit and attached, so that the guide part loosely fits into the mating screw part and the two screw parts are inclined and screwed together. The trouble that the screw portion is damaged and the screw portion becomes so-called screw stupid is eliminated.

[Brief description of the drawings]

FIG. 1 is a partially enlarged cross-sectional view of a power element unit attaching portion to a main body block according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of a power element unit mounting portion to a main body block according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing the overall configuration of the expansion valve according to the embodiment of the present invention.

FIG. 4 is a perspective view of a diaphragm receiver of the expansion valve according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Low-pressure refrigerant flow path 13 High-pressure refrigerant flow path 16 Valve element 20 Rod 25a Male screw part 25b Female screw part 25c Guide part 30 Power element unit 31 Housing 32 Diaphragm 33 Diaphragm receiving board

Claims (1)

[Claims] 1. 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. The expansion valve in which a power element unit for opening and closing the valve body in accordance with the temperature and pressure of the low-pressure refrigerant is screwed into the main body block and attached, wherein a screw portion of the power element unit has a screw of the main body block. At least one of the screw end on the power element unit side and the screw end on the body block side, which first screw together when screwed into the part, is loosely fitted to the screw part on the other side, and the two screw parts An expansion valve, wherein a guide portion for restricting screwing in a tilted state is formed.