JP2001159465A - Structure of seal part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of a seal part, having satisfactory sealing performance by preventing a sealing failure from being easily generated caused by pinching of foreign matters. SOLUTION: In a structure for a seal part, an annular sealing member 26 having elasticity is fitted in an annular groove 24, having the approximately rectangular section in the width direction and having one surface out of four surfaces formed on the outer surface, and a rigid coating seal member 31 is brought into pressure-contact with the seal member 26 from the opened surface side of the annular groove 24. An annular recessed groove 124 or a protrusion 224, extending over the whole circumference of the annular groove 24, is formed on the bottom surface of the annular groove 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a seal portion for preventing leakage of a fluid in an expansion valve and other mechanical devices of 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 disposed and a valve element is opened and closed by a power element that operates according to the temperature and pressure of a low-pressure refrigerant sent from an evaporator is widely used.

In such a power element, for example, as shown in FIG. 7, a male screw portion 25a formed on an outer peripheral surface of a cylindrical portion formed on a power element 30 is formed by opening a mounting hole of a main body block 11. It is attached to the main body block 11 by being screwed into a female screw portion 25b formed in the portion.

[0004] An annular groove 24 formed in a spot facing shape around the opening of the mounting hole on the main body block 11 side is formed.
An elastic annular seal member 26 is fitted, and the outer wall surface of the power element 30 is pressed against the seal member 26 to perform sealing.

[0005]

However, in such a simple sealing structure, a fine foreign substance (for example, a fine fibrous material cut out from a screw portion when the power element 30 is screwed into the main body block 11 and attached). Burrs, etc.) are merely sandwiched in the annular groove 24, which may result in incomplete sealing and refrigerant leakage.

Accordingly, an object of the present invention is to provide a structure of a seal portion having good sealability, in which poor sealing is less likely to occur due to foreign matter being caught.

[0007]

In order to achieve the above-mentioned object, the structure of the seal portion of the present invention has a cross section in the width direction formed substantially rectangular, and only one of the four surfaces is open to the outside. In the structure of the seal portion in which a resilient annular seal member is fitted into the annular groove, and a rigid member to be sealed is pressed against the seal member from the open surface side of the annular groove, An annular groove or projection is formed over the entire circumference of the annular groove. In addition, the edge of the concave groove which is the boundary with the bottom surface of the annular groove may be formed to be angular.

In addition, a valve body is disposed in the main body block so as to face a valve seat hole formed by narrowing the middle of a high-pressure refrigerant passage through which the high-pressure refrigerant sent into the evaporator passes. A power element that opens and closes the valve body in accordance with the temperature and pressure of the low-pressure refrigerant is screwed into an opening of a mounting hole formed in the main body block. The above-described annular groove may be formed around the portion with the annular bank portion interposed therebetween.

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows an expansion valve to which the present invention is applied. In the figure, 1 is an evaporator, 2 is a compressor, 3 is a condenser,
Reference numeral 4 denotes a receiver connected to the outlet side of the condenser 3 and containing a high-pressure liquid refrigerant, and 10 denotes 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 is made of, for example, an aluminum alloy or the like.
A low-pressure refrigerant passage 12 for passing low-temperature and low-pressure refrigerant gas sent from the compressor to the compressor 2 and a high-pressure refrigerant passage 13 for adiabatic expansion through a high-temperature and high-pressure refrigerant liquid sent to the evaporator 1 are provided in the main body block 11. Is formed.

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. 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, and the downstream flow from the evaporator 1 to the narrowed part. In the passage, the high-pressure refrigerant adiabatically expands.

The valve body 16 is made of, for example, a metal such as stainless steel. The open end of the valve seat hole 15 facing the valve body 16 is formed in a tapered chamfered shape so as to spread outward. I have.

The valve body 16 has a tapered compression coil spring 1 whose winding diameter gradually decreases toward the valve body 16.
7 urges in a direction approaching the valve seat hole 15 (that is, 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). 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. The fixing position of the spring receiving member 18 is adjusted by adjusting the screwing amount so as to obtain the value. Reference numerals 22a and 22b denote the screw portions, and reference numeral 18a denotes a tool engagement hole.

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

The rod 20 inserted into the through hole 14 is
It is slidably provided in the axial direction, the upper end reaches near the back surface of the power element 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 coolant flow path is formed between the rod 20 and the wall surface of the valve seat hole 15. At a position slightly away from the low-pressure refrigerant flow path side opening 14 a of the through hole 14, a projection 23 is formed on the rod 20.
Is protruding.

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.

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 portion of the housing 31 near the main body block 11 is formed in a cylindrical shape, and a male screw portion 25a is formed on the outer peripheral surface thereof. And the male screw part 25
a is screwed into the female screw portion 25b formed in the opening of the mounting hole of the main body block 11, and the power element 3
0 is attached to the main body block 11. Reference numeral 26 denotes a sealing member, for example, a rubber O-ring having a circular cross section is used.

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 plate 33 is disposed facing the rear surface of the diaphragm 32, and the end of the rod 20 is in contact with the rear surface of the diaphragm receiving plate 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.

A slope 36 is formed at the center of the rear surface of the diaphragm receiving plate 33, and the leg 33a formed by bending the peripheral portion loosely fits into the inner peripheral surface of the housing 31 to form the diaphragm receiving plate 33. Has the function of stabilizing the posture of the user.

A rod receiver 37 into which the rod 20 is slidably fitted in the vicinity of the end is formed in the central part of the part 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 flow path 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.

FIG. 1 shows a structure of a sealing portion for sealing a mounting portion of the power element 30 with respect to the main body block 11, and a resilient annular sealing member 26 is provided.
Around the opening of the mounting hole formed in the main body block 11, it is fitted into an annular groove 24 formed with a bank portion 27 formed in an annular shape and interposed therebetween.

As described above, the annular groove 24 is
Since the bank 27 is formed between the threaded portions (25a, 25b) of the main body block 11 and the threaded portions (2a, 25b), when the housing 31 is screwed into the body block 11, the threaded portions (2
5a, 25b) are formed in the annular groove 24.
It is hard to get into the side.

As shown in FIG. 1, the annular groove 24 has a substantially rectangular cross section in the width direction, and only one of the four surfaces (the surface facing outward) is open to the outer surface. And the other three sides are completely closed.

In the natural state, the sealing member 26 is
4, the housing 31 of the power element 30 is screwed into the main body block 11, and the housing 31 is pressed against the seal member 26 from the open surface side of the annular groove 24. The elastic seal member 26 is crushed.

On the bottom surface of the annular groove 24, an annular concave groove 124 is formed over the entire circumference of the annular groove 24. The concave groove 124 has a V-shaped cross-sectional shape in this embodiment, and the top is rounded, but the edge 124 a that forms a boundary with the bottom surface of the annular groove 24 is formed to be angular. Have been.

As a result, the elastic sealing member 26
Is deformed in the annular groove 24 and further fits into the concave groove 124, and is pressed against the angular edge 124 a of the concave groove 124 to be deformed, so that the sealing property is remarkably improved. Even if minute foreign matter enters and is caught between the bottom surface of the annular groove 24 and the seal member 26, it is unlikely that refrigerant leakage or the like occurs.

It should be noted that the present invention is not limited to the above-described embodiment. For example, as shown in FIG.
A plurality of grooves 124 may be provided on the bottom surface of the groove 4, and as shown in FIGS. 4 and 5, the cross-sectional shape of the groove 124 may be other than V-shaped (for example, rectangular or semicircular). .
3 to 5, illustration of the seal member 26 and the housing 31 is omitted.

Further, as shown in FIG.
Instead of the annular projection 224 over the entire circumference of the annular groove 24.
May be formed, and the same sealing effect as in the case of the concave groove 124 can be obtained at the tip of the projection 224.

The present invention can be widely applied not only to the expansion valve of the refrigeration cycle but also to the structure of a seal portion for sealing a fluid in a mechanical device. Further, the cross-sectional shape of the seal member 26 is not limited to a circle, but may be a rectangle or the like.

[0042]

According to the present invention, a resilient annular seal member is fitted into an annular groove having a cross section in the width direction which is substantially rectangular and only one of the four surfaces is open to the outside. In the structure of the seal portion in which the rigid member to be sealed is pressed against the seal member from the open surface side of the annular groove, an annular concave groove or a protrusion is formed on the bottom surface of the annular groove over the entire circumference of the annular groove. As a result, the seal member is deformed at that portion and is strongly pressed against the wall surface of the bottom of the annular groove, so that the sealing property is improved.

By forming an annular groove around the opening of the mounting hole of the main body block of the expansion valve with an annular bank portion interposed therebetween, a portion for screwing the power element to the main body block is formed. Therefore, even if cutting chips or the like are generated at the time of screwing, the chips are unlikely to move to the annular groove side, and poor sealing due to foreign matter being caught is unlikely to occur.

[Brief description of the drawings]

FIG. 1 is a partially enlarged cross-sectional view of a structure of a seal portion according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the expansion valve according to the embodiment of the present invention.

FIG. 3 is a partially enlarged sectional view of an annular groove according to a second embodiment of the present invention.

FIG. 4 is a partially enlarged sectional view of an annular groove according to a third embodiment of the present invention.

FIG. 5 is a partially enlarged sectional view of an annular groove according to a fourth embodiment of the present invention.

FIG. 6 is a partially enlarged sectional view of a structure of a seal portion according to a fifth embodiment of the present invention.

FIG. 7 is a partially enlarged cross-sectional view of a structure of a conventional seal portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Main body block 16 Valve body 24 Annular groove 25a Male screw part 25b Female screw part 26 Seal member 27 Bank part 30 Power element 31 Housing (member to be sealed) 124 Concave groove 124a Edge 224 Projection

Claims (3)

[Claims] 1. A resilient annular sealing member is fitted into an annular groove having a cross section in the width direction formed substantially in a rectangular shape and only one of the four surfaces is opened to the outer surface, and the annular groove is opened. In the structure of the sealing portion in which a rigid member to be sealed is pressed against the sealing member from the surface side, an annular groove or a projection is formed on the bottom surface of the annular groove over the entire circumference of the annular groove. The structure of the seal part. 2. The structure of a seal portion according to claim 1, wherein an edge of said concave groove, which is a boundary portion with a bottom surface of said annular groove, is formed angularly. 3. A valve body is disposed in a main body block so as to face a valve seat hole formed by narrowing a middle of a high-pressure refrigerant flow path through which a high-pressure refrigerant fed into an evaporator passes. A power element that opens and closes the valve body in accordance with the temperature and pressure of the low-pressure refrigerant that has been sent out is an expansion valve that is screwed to an opening of a mounting hole formed in the main body block. 3. The structure of the seal portion according to claim 1, wherein the annular groove is formed around an opening of the mounting hole with an annular bank portion interposed therebetween.