JPS631156Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an expansion valve used in car air conditioners and other air conditioners.In particular, the body part, which was conventionally made of metal material, is replaced with a molded part made of synthetic resin material. At the same time, the purpose is to improve airtightness.

Most of the conventional expansion valves of this type are manufactured by hot forging or die-casting metal materials such as brass, and then undergoing many machining processes such as lathe cutting, thread cutting, and drilling. A valve body 1 as shown in FIG. 7 was formed. As a result, a large number of machining processes are required for one material, which significantly increases costs.Also, cutting waste of 30 to 40% of the original material is generated, resulting in wasted material and work time. The huge consumption of
It was not suitable for mass production. Here, to explain this type of conventional expansion valve with reference to FIG. 8, a cavity 3 having a circular rising wall 2 is formed on the upper surface of a metal valve body 1, and a central bottom surface of this cavity is formed. A movable piece 4 for operation is positioned, and the periphery of the upper lid 6, whose central portion is bulged upward, is placed inside the rising wall 2 above the diaphragm 5 housed in the cavity so as to be in contact with the upper surface of the movable piece. The rising wall 2 is caulked toward the center to maintain its strength, and the inner circumference 9 of the rising wall 2 where the upper lid 6 and the diaphragm 5 contact is soldered to the outside. , and Vacant Room 3 were sealed.

In order to eliminate these conventional drawbacks and reduce the number of machining steps, the present invention eliminates most of the machining work such as lathe cutting by making the valve body from synthetic resin by injection molding or other molding methods. In addition to reducing weight and material consumption,
This improves the airtightness of the cavity formed by the upper lid and the diaphragm and the cavity provided in the upper part of the valve body. However, if the diaphragm 5, which responds to the pressure generated in the cavity 7 filled with gas, is made of synthetic resin, the filled gas will leak, so at this stage a metal diaphragm must be used. . This metal upper cover is used to compensate for the low reliability of welding between the metal of the diaphragm and the resin of the valve body (compared to welding between metals), and to strengthen the welding between the capillary reach tube and the pressure resistance. This improves airtightness with the valve body.

The embodiments of the present invention will be explained with reference to the drawings.
is a valve body molded by injection molding or the like using a synthetic resin with a low coefficient of thermal expansion and relatively high hardness. Reference numeral 12 designates a first chamber formed inwardly from the bottom of the valve body 11, and 13 designates a second chamber that opens on one side of the valve body 11.
The interior of the chamber and the interior of the first chamber 12 are communicated through a port 14, and a recess 16 is provided around the upper surface of the valve body 11 in which a circular raised portion 15 is formed.
A disc-shaped movable plate 17 is placed at the center of the bottom surface of this recess 16.
The recess 16 and the first chamber 12 are communicated with each other through a plurality of small holes 18, and the small holes 18
The upper ends of rod rods 19, 19 inserted vertically movably therein are brought into contact with the lower surface of the movable plate 17, and the lower portions of these rod rods 19, 19 are made to protrude into the first chamber 12. . Reference numeral 20 denotes a threaded portion formed on a substantially intermediate circumferential wall of the first chamber 12, and an adjustment ring 21 is threadably engaged with this threaded portion 20. 22 is on the top edge,
A movable body that holds a spring pin 24 to which a ball valve 23 for opening and closing the port 14 is fixed.
5 is pressed upward. The upper surface of the movable body 22 engages the lower end of the rod 19, and a ball valve 23 provided at the upper center of the movable body is connected to the port 1.
4, the first chamber 12 and the second chamber 13 are isolated or communicated with each other. Also, valve body 1
An annular engagement step 26 is formed one step higher between the raised portion 15 provided on the upper surface periphery of the recess 16 and the bottom surface periphery of the recess 16.
8 is formed.

In FIG. 2, reference numeral 30 denotes a thin metal diaphragm, which is provided with an annular extensible portion 31 approximately at its periphery and a raised portion 32 that rises upward at the periphery. Reference numeral 35 denotes a metal upper lid with a central portion bulging upward; the tip of a capillary reach tube 36 is passed through and welded to this upper lid 35, and then this upper lid 35 is housed in the raised portion 32 of the diaphragm. death,
The upper lid 35 and the upright portion 32 are fixed together circumferentially at a welded portion 37 by soldering or other methods to form an upper housing A having a cavity 38 inside.

Another embodiment of the upper housing will be described with reference to FIGS. 5 and 6. The upper housing has a circular diaphragm 40 made of metal that has an expandable portion 41 on its periphery, and a bulge portion that has approximately the same shape as the diaphragm 40 and a bulge portion above the center portion. The metal upper lid 45 provided with the above is overlapped, and the peripheral portion is welded and fixed by soldering, seam welding, or other methods to form an upper housing B having an airtight cavity 48 inside. Incidentally, the tip of a capillary reach tube 46 is passed through the upper lid 45 and fixed thereto in an airtight manner.

First, the O-ring 28 is accommodated in the concave groove 27, and then the upper housing A is accommodated in the rising part 15, and the annular holding resin ring 50 is inserted into the rising part 15 from above. The lower part of the resin is placed in the upper housing A so that the lower part is in contact with the upper surface of the upper housing A, and the contact area between the diaphragm 30 and the O-ring 28 is sufficiently pressed to maintain airtightness between the recess 16 and the diaphragm 30. With the ring 50 pressed downward, the protrusion 51 provided on the resin ring is ultrasonically welded to the inclined surface 15a provided inside the upper part of the rising part 50, by applying an adhesive, or by other known methods. The rising portion 15 and the resin ring 50 are welded and fixed.

After this upper housing A is fixed to the upper part of the valve body 11, the air in the cavity 38 is removed from the other end (not shown) of the capillary reach tube 36 using a vacuum pump, and then a predetermined amount of refrigerant gas and other substances are pumped out. The cavity 38 and the capillary reach tube 36 are filled, and the filling port at the other end of the capillary reach tube is sealed by brazing or other methods to prevent the sealed gas from leaking to the outside permanently. Next, this expansion valve is set in a test and adjustment device, and the adjustment ring 21 is adjusted while testing to obtain a predetermined expansion valve characteristic.

In this case, among the various functions of the expansion valve, the cavity 38
The amount of refrigerant sealed inside the valve is small, only a few grams, and must be prevented from leaking over a short period of time. Various methods such as bonding, argon welding, and soldering can be employed relatively easily and there are few problems. However, when using the resin valve body of the present application, metal parts must be used for the upper housing due to pressure resistance and other reasons as described above, and joining or welding the resin parts and metal parts requires Reliability with respect to leakage of refrigerant etc. from these welded parts etc. becomes a problem. Furthermore, regarding leakage from the expansion valve, valve body 1
Although there are leaks from the wall surface due to pinholes, cracks, etc. within the 1, and leaks due to similar causes from other parts, the majority of leaks are from the welded part between the upper cover 35 and the diaphragm 30, and the capillary reach tube. 36 and the upper lid 35, a weld at one end of the capillary reach tube (not shown), and a joint between the diaphragm 30 and the recess 16. Particularly disadvantageous are the joint between the diaphragm 30 and the upper lid 35 and the joint between the diaphragm 30 and the valve body 11, which have a larger circumferential area than other parts. In order to eliminate such concerns, we have designed the resin expansion valve to avoid welding the resin and metal.
If the diaphragm 30 is made of a metal such as a phosphor bronze plate, and the upper cover 35 is made of a metal such as a brass plate, solder welding is used, and if the metal material cannot be soldered, it may be welded by brazing or the like. Do it with Therefore, leakage of the refrigerant within the cavity 38 can be avoided if the metals are completely welded together.

Next, the upper housing A and the recessed portion 16 are sealed by an O-ring 28 housed in the recessed groove 27. However, since the O-ring 28 is made of a rubber material, there is permeation leakage, so slight leakage from this part is unavoidable, but this part is not related to the cavity 38 side. An expansion valve is connected and used through a passage leading from the cavity 29 provided between the recess 16 and the diaphragm 30 to the first chamber 12 through the space around the rod 19 and the pressure equalization communication hole (not shown). This can cause refrigerant leaks in the refrigerant system.
The amount of refrigerant charged in the system is relatively large, for example 400 g or more, and if the leakage from the sealing part of the O-ring 28 is about 0.5 g/year, it will not be a practical problem, so it is necessary to set a certain limit. It is set and allowed. In addition, the force (pressure x diaphragm pressure-receiving area) by which the upper housing A is lifted by the pressure applied to the cavity 29 can be obtained by ultrasonically welding the resin ring 50 to the upper part of the upright portion 15 of the valve body or by fixing it by another welding method. It is supported by

Note that the adoption of resin parts is not limited to the valve body 11, but machining costs can be reduced by using the same resin material as the valve body for many parts such as the movable piece 17, rod 19, movable body 22, and adjustment ring 21. By using the same material and having the same expansion coefficient, good effects are produced in terms of dimensional accuracy and performance, but this is synergistically improved by using resin for the valve body. This is an effect that appears.

The expansion valve according to the present invention has a valve body 11 which is molded from synthetic resin and has a recess 16 having an upright part 15 around the upper part, and a recess 27 for accommodating an O-ring on the bottom surface of the peripheral edge of the recess 16. and,
An upper housing A having a cavity 38 inside by airtightly fixing the peripheral edge of a metal diaphragm 30 and the peripheral edge of a metal upper lid 35 which penetrates the tip of a gear pillar reach tube 36 and fixes the tip airtightly. The diaphragm 30 of the upper housing A housed in the upright part 15 and the O-ring 28 housed in the groove 27 are in contact with each other, and a resin ring 50 is positioned above the upper housing.
is fixed to the upright portion 15 via the upper housing A, so that it has the following effects.

The valve body, which accounts for most of the weight of the expansion valve, is formed by resin injection molding, which significantly reduces the weight.In addition, the machining process can be significantly omitted, making it suitable for mass production. Cost reduction can be achieved.

Metals and resins can be bonded together by welding or adhering metals or resins together, such as a metal upper lid and a metal diaphragm, or a valve body upper body and a resin ring. It is possible to avoid the problem of resin creep at the joint welding part due to the difference in temperature expansion between can be eliminated and reliability can be increased.

[Brief explanation of drawings]

The drawings show the first embodiment of the present invention, in which Fig. 1 is an overall sectional view, Fig. 2 is a sectional view of the diaphragm, Fig. 3 is a partially cutaway sectional view of the upper housing, and Fig. 4 is a sectional view of the diaphragm. 5 and 6 show the second embodiment, FIG. 5 is a sectional view of the diaphragm, and FIG. 6 is a partially cutaway sectional view of the upper housing.
Figures 7 and 8 show conventional expansion valves.
The figure is a sectional view of a metal valve body, and FIG. 8 is a partially cutaway front view of the entire valve body. 11 is a resin valve body, 15 is a rising part,
16 is a recess, 27 is a groove, 28 is an O-ring, 3
0 is a metal diaphragm, 35 is a metal upper lid, 36 is a capillary tube, 38 is a cavity, 5
0 is the resin ring, A is the upper housing.

Claims (1)

[Scope of utility model registration request] The valve body is made of synthetic resin, has a recessed part around the upper part with a raised part, and has a recessed groove for accommodating an O-ring on the bottom of the peripheral part of this recessed part, and the peripheral part of the metal diaphragm and the valve body. The upper housing is made up of a peripheral edge of a metal upper lid which is fixed airtightly by penetrating the tip of the pillar reach tube and has a hollow inside, and the upper housing is housed in the upright part. The expansion valve comprises a diaphragm and an O-ring housed in the groove, and a resin ring positioned above the upper housing and fixed to the upright part via the upper housing.