JPH0979703A - Thermo-sensitive expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a durability of a diaphragm part at an element segment. SOLUTION: An outer peripheral edge part of a diaphragm 49 is integrally held between a receiver member 55 and a lid member 56 through a ring member 57 in a sandwich form. A supporting fulcrum position where a diaphragm 49 is displaced is set at the inner circumferential end of the ring member 57. Since the ring member 57 has a simple shape, it is possible to form it in an accurate manner like a washer member. Accordingly, the fulcrum point position of the diaphragm 49 when this member is displaced can be positively set at the inner peripheral end of the ring member 57. Since the inner circumferential end position of the ring member 57 is spaced apart from a connecting location A at the outer circumferential end of the diaphragm 49, the diaphragm 49 is hardly influenced with thermal effect caused by welding operation. Thus, there is a low possibility that a hardness degree of the diaphragm 49 at its fulcrum point position is reduced under a thermal expansion caused by welding operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal expansion valve for decompressing a high-temperature high-pressure liquid refrigerant into a low-temperature low-pressure gas-liquid two-phase refrigerant in a refrigeration cycle, and is suitable for use in, for example, an air conditioner for automobiles. It is something.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a temperature type expansion valve has a temperature sensitive tube 53 for sensing the temperature of the refrigerant at the outlet of the evaporator of a refrigeration cycle, and the pressure of the enclosed gas in the temperature sensitive tube 53. Is introduced into the first pressure chamber 50 of the element portion 4 ', and the evaporator side pressure (low pressure) of the refrigeration cycle is introduced into the second pressure chamber 51. The diaphragm 49 made of metal (stainless steel) is displaced according to the spring force of the coil spring 46, and the opening degree of the refrigerant throttle passage 43 is adjusted by the valve body 44.

Further, the diaphragm 49 is sandwiched between the receiving member 55 and the lid member 56 at the outer peripheral edge portion thereof, and these members 55, 56 and the diaphragm 49 are integrally joined by welding to form an outer peripheral portion of the diaphragm 49. Is fixed and sealed. In FIG. 3, a portion A indicates a joint portion by the above-mentioned welding.

[0004]

By the way, the receiving member 55 and the lid member 56 are manufactured by press-molding a metal material such as stainless steel, but their shapes are complicated as shown in FIG. The number of steps of press molding increases, and variations in the shapes and dimensions of the receiving member 55 and the lid member 56 are likely to occur. In addition to this, as the number of times the press die is used increases, wear of the press die occurs and the receiving member 5
5 and the lid member 56 have sagging.

Thus, the receiving member 55 and the lid member 5
When the shape and size of 6 are varied or sagged, the contact member 55 and the lid member 56 are expanded at the contact portion with the diaphragm 49, and the fulcrum position when the diaphragm 49 is displaced is the outermost welding point A. May move to. Since the strength of the diaphragm 14 is lowered due to the heat effect of the welding at the welded portion A, the durability of the diaphragm 14 may be deteriorated when the welded portion A becomes the fulcrum position of the diaphragm 14. It was

In view of the above points, an object of the present invention is to provide a thermal expansion valve which can surely improve the durability of a pressure responsive member such as a diaphragm with a simple structure.

[0007]

SUMMARY OF THE INVENTION To achieve the above object, the present invention employs the following technical means. That is, in the invention according to claim 1, the outer peripheral edge portion of the pressure responsive member (49) such as a diaphragm is provided between the receiving member (55) and the lid member (56).
The sandwiched member is sandwiched via the ring member (57) and integrally joined, and the fulcrum position when the pressure responsive member (49) is displaced is set to the inner peripheral end of the ring member (57). It features a thermal expansion valve.

According to the second aspect of the invention, the pressure responsive member (49) is provided at the inner peripheral end of the ring member (57).
It is characterized in that a circular arc surface (57a) is formed in a portion that comes into contact with. In the invention according to claim 3, a protrusion (55b) for positioning the inner peripheral end of the ring member (57).
Is formed on one of the receiving member (55) and the lid member (56) on the side with which the ring member (57) abuts.

According to the invention described in claims 1 to 3, the ring member has a simple shape by the above-mentioned technical means, so that the ring member can be accurately molded like a washer. Therefore, the fulcrum position when the pressure responsive member is displaced can be reliably set to the inner peripheral end of the ring member. Since the inner peripheral end position of this ring member is separated from the joint portion A at the outer peripheral end of the pressure responsive member, the pressure responsive member is less susceptible to the thermal effect of welding. Therefore, it is less likely that the hardness of the fulcrum position of the pressure responsive member will decrease due to the heat effect of welding.

As a result, compared with the prior art in which the pressure responsive member may be displaced with the joint A as the fulcrum position,
The product of the present invention in which the pressure responsive member is displaced with the inner peripheral end of the ring member as the fulcrum position can contribute much more to the durability improvement of the pressure responsive member. Further, according to the second aspect of the present invention, since the pressure responsive member can be smoothly displaced by the arcuate surface formed on the inner peripheral end of the ring member, there is no fear of damage at the fulcrum position of the pressure responsive member.

Further, according to the third aspect of the invention, since the inner peripheral end of the ring member can be easily positioned by the projection, the ring member can be easily assembled.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 illustrate an embodiment in which the present invention is applied to a temperature type expansion valve of a refrigeration cycle for an automobile air conditioner. The refrigeration cycle is a compressor 1 driven by an automobile engine, and is discharged from the compressor 1. A condenser 2 for cooling and condensing the gas refrigerant, a receiver 3 for accumulating the refrigerant from the condenser 2 to separate the gas-liquid of the refrigerant and discharging only the liquid refrigerant, a thermal expansion valve 4 according to the present invention. , And an evaporator 5 for evaporating the low-temperature low-pressure gas-liquid two-phase refrigerant decompressed and expanded by the temperature type expansion valve 4.

Next, the temperature type expansion valve 4 will be described in detail. Reference numeral 40 denotes a valve housing formed of a metal such as aluminum, which has a cylindrical refrigerant inlet 41 into which the liquid refrigerant from the liquid receiver 3 is introduced, and It has a cylindrical refrigerant outlet 42 communicating with the inlet side of the evaporator 5. A throttle passage 43 for reducing the pressure of the refrigerant is provided between the refrigerant inlet 41 and the refrigerant outlet 42. The opening of the throttle passage 43 can be adjusted by a spherical metal valve body 44. I have.

The spherical valve element 44 is movable in the vertical direction in FIG. 1, and a spring receiving seat 45 is arranged on the lower side thereof, and one end of a coil spring 46 abuts on this receiving seat 45. Supported. The other end of the coil spring 46 is in contact with and supported by a mounting load adjusting plate (not shown) movably mounted on the inner wall surface of the cylindrical refrigerant inlet 41 by screwing.

One end of a metal valve actuating rod 47 is joined to the upper side of the spherical valve element 44 in FIG. 1 by welding or the like, and the other end of the valve actuating rod 47 is in contact with a stopper member 48. . The stopper member 48 is always in contact with a diaphragm (pressure responsive member) 49 to transmit the displacement of the diaphragm 49 to the valve operating rod 47. Diaphragm 4
First and second pressure chambers 50 and 51 are formed above and below 9, respectively, and the capillary tube 5 is provided in the first pressure chamber 50.
A temperature-sensing cylinder 53 that senses the refrigerant temperature at the outlet of the evaporator 5 communicates with the gas pressure inside the temperature-sensing cylinder 53 (gas saturation pressure corresponding to the refrigerant temperature at the outlet of the evaporator 5). It is adapted to be introduced into the first pressure chamber 50.

Further, the low pressure side refrigerant pressure downstream of the throttle passage 43 is introduced into the second pressure chamber 51 through a communication hole (internal pressure equalizing passage) 54 formed in the valve housing 40. . The first and second pressure chambers 50 and 51
Is the diaphragm 49, the receiving member 55, and the lid member 5.
It is constituted by a sandwich structure with 6 and the element part 4'of the expansion valve 4 is formed by this sandwich structure.
Is configured.

Since the present invention is characterized by the construction of the element portion 4 ', the element portion 4'will be described below with reference to FIG.
This will be described in detail with reference to an enlarged sectional view of FIG. The diaphragm 49, the receiving member 55, and the lid member 56 are all formed by press-molding a metal having excellent corrosion resistance such as stainless steel into a predetermined shape shown in the drawing. A ring-shaped flat recess 55a is formed in the vicinity of the outer peripheral portion of the receiving member 55,
A ring member 57 made of metal such as copper having excellent processing accuracy and corrosion resistance is disposed in the recess 55a. The ring member 57 is positioned by a ring-shaped protrusion 55b located on the inner peripheral side of the recess 55a of the receiving member 55.

Further, in the ring member 57, a smooth circular arc surface (R portion) 57a is formed on the inner peripheral side surface of the ring member 57 which is in contact with the diaphragm 49, and the circular arc surface 57a is formed. Serves as a fulcrum position when displaced in the downward direction of the drawing, and prevents the diaphragm 49 from being damaged. The ring member 57 can be easily manufactured by cutting a metal pipe.
On the outer peripheral side of the lid member 56, a support surface 56a on which the diaphragm 49 abuts and is supported extends in a substantially horizontal direction.

When assembling the element portion 4 ',
After disposing the ring member 57 in the recess 55 a of the receiving member 55, the diaphragm 49 is formed by the receiving member 55 and the lid member 56.
The outer peripheral edge portion of is sandwiched in a sandwich shape, and the outer peripheral edge portions of these three members are pressure bonded. After that, the outer peripheral edge portions of the three members are integrally joined by welding (for example, TIG welding). A of FIG. 2 shows the joining part. The center hole of the receiving member 55 is airtightly screwed and fixed to the valve housing 40. A capillary tube 52 is joined to the center of the lid member 56 by brazing or the like, and the capillary tube 52 communicates with a temperature sensitive tube 53 at the outlet of the evaporator 5.

According to the above construction, since the ring member 57 has a simple shape, it can be molded with high precision like washers. Therefore, the fulcrum position when the diaphragm 49 is displaced can be reliably set to the inner peripheral end of the ring member 57. The position of the inner peripheral end of the ring member 57 is at the joining point A.
Since they are farther apart, the diaphragm 49 is less likely to be affected by the heat of welding. Therefore, it is less likely that the hardness of the fulcrum position of the diaphragm 49 will decrease due to the heat effect of welding.

As a result, the embodiment of the present invention in which the diaphragm 49 is displaced with the inner peripheral end of the ring member 57 as the fulcrum position is generated as compared with the conventional technique in which the diaphragm 49 is displaced with the joint portion A as the fulcrum position. However, the durability of the diaphragm 49 can be greatly improved. Further, since the diaphragm 49 can be smoothly displaced by the arcuate surface 57a formed at the inner peripheral end of the ring member 57, there is no fear of scratches at the fulcrum position of the diaphragm 49.

Since the refrigerant flow rate adjusting operation of the expansion valve 4 is the same as that of the conventional one, its outline will be described. In the first pressure chamber 50, the temperature of the evaporator outlet refrigerant sensed by the temperature sensing cylinder 53 is changed. The gas pressure is introduced, while the refrigerant pressure (low pressure) at the outlet of the throttle passage 43 (evaporator inlet) is introduced into the second pressure chamber 51 through the communication hole (internal pressure equalizing passage) 54.

Further, the coil spring 4 is attached to the valve body 44.
6, the spring force acts in the valve closing direction (upward in FIG. 1). Therefore, the diaphragm 49 is displaced according to the pressure difference between the first and second pressure chambers 50 and 51 and the spring force in the valve closing direction from the coil spring 46, and the valve is displaced according to the displacement of the diaphragm 49. The body 44 moves to adjust the opening degree of the throttle passage 43 and control the refrigerant flow rate.

By this refrigerant flow rate control operation, the degree of superheat of the refrigerant at the outlet of the evaporator 5 is maintained at a predetermined value determined by the spring force of the coil spring 46. (Other Embodiments) Although the ring member 57 is arranged between the receiving member 55 and the diaphragm 49 in the above-described embodiment, the ring member 57 is arranged between the lid member 56 and the diaphragm 49. Even if it is provided, the same effect can be obtained.

Further, since the ring member 57 has a ring shape, it is possible to position the ring member 57 on the outer peripheral surface thereof, so that the protrusion 55b provided on the receiving member 55 can be omitted. Further, in the above-described embodiment, the refrigerant pressure (low pressure) at the outlet (evaporator inlet) of the throttle passage 43 is passed through the communication hole (internal pressure equalizing passage) 54 in the second pressure chamber 51.
The so-called internal pressure equalization type expansion valve, in which is introduced, has been described.
It goes without saying that the present invention can be applied to a so-called external pressure equalizing type expansion valve that introduces the refrigerant pressure at the outlet of the evaporator 5.

[Brief description of drawings]

FIG. 1 is a view in which a half cross-sectional front view and a refrigeration cycle diagram of an expansion valve according to an embodiment of the present invention are combined.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is a half sectional front view showing a conventional expansion valve.

[Explanation of symbols]

4 '... Element part, 49 ... Diaphragm, 50 ... First
Pressure chamber, 51 ... Second pressure chamber, 55 ... Receiving member, 56
... Lid member, 57 ... Ring member.

Claims (3)

[Claims] 1. A thermal expansion valve for decompressing and expanding a high-pressure side refrigerant in response to a superheat degree of the refrigerant at an outlet of an evaporator (5) of a refrigeration cycle, the housing member (40) and the housing. A throttle passage (43) provided in the member (40) for decompressing and expanding the high-pressure side refrigerant, and a valve body (44) provided in the housing member (40) for adjusting the opening degree of the throttle passage (43). ) And an element portion (4 ′) for actuating the valve body (44), the element portion (4 ′) being the housing member (4).
0), the receiving member (55), the lid member (56) for covering the receiving member (55), and the evaporator (5).
The pressure responsive member (49) is displaced according to the refrigerant temperature at the outlet and the refrigerant pressure on the downstream side of the throttle passage (43), and the outer peripheral edge of the pressure responsive member (49) is the receiving member (55). And the lid member (56) are sandwiched by a ring member (57) in a sandwich shape and integrally joined, and the fulcrum position when the pressure responsive member (49) is displaced is set to the fulcrum position. It is set at the inner peripheral end of the ring member (57), and the displacement of the pressure responsive member (49) is transmitted to the valve body (44) to adjust the opening degree of the valve body (44). A thermal expansion valve. 2. A circular arc surface (57a) is formed at a portion of the inner peripheral end of the ring member (57) that comes into contact with the pressure responsive member (49).
The thermal expansion valve described in. 3. A protrusion (55b) for positioning an inner peripheral end of the ring member (57) is provided in the ring member (5) of the receiving member (55) and the lid member (56).
The thermal expansion valve according to claim 1 or 2, wherein 7) is formed on a member on the side where it abuts.