JP2004125238A - Valve element for four-way switching valve, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve element for a four-way switching valve having both an advantage possessed by a metallic valve element and an advantage possessed by a resin valve element, and causing no crack and breakdown in the valve element. <P>SOLUTION: The bowl-shaped valve element 16 is used for the four-way switching valve, and is composed of a metallic core material part 20, a reinforcing metallic pin 23 integrally fixed in advance by welding by being extended so as to cross an opening end surface part of this metallic core material part 20 and a resin coating film layer 40 integrated thereafter by injection molding into the outside surface side and an annular collar part 20b of the metallic core material part 20. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a valve element for a four-way switching valve used in a reversible refrigeration cycle in an air conditioner or the like, and a method for manufacturing the same.
[0002]
[Prior art]
BACKGROUND ART Conventionally, a four-way switching valve is provided in a refrigerant passage of a refrigeration cycle, and the refrigerant passage is switched by the four-way switching valve, for example, to switch between indoor cooling and heating.
Various such four-way switching valves have been proposed. As one of them, a connection port for the discharge pipe of the compressor and a connection port for the suction pipe of the compressor are provided in the cylindrical valve body, and two heat ports are provided on both sides of the connection port for the suction pipe of the compressor. A connection port for the conduit communicating with the exchanger is arranged, and a bowl-shaped valve body is slidable so as to cover the connection port for the suction pipe located at the center and the connection port for the conduit communicating with one adjacent heat exchanger. , The fluid pressure is supplied to the working chamber between the piston and the plug provided on both sides of the valve body, and the valve body is slid by discharging the fluid pressure in the other working chamber. A connection between a connection port and one of the connection ports on both sides is known.
[0003]
As a valve element of such a four-way switching valve, for example, there is a valve element formed of metal.
However, in order for the valve body made of metal to slide the upper part of the connection port such as the suction pipe in an airtight manner, the sliding surface of the valve body must be smoothed, which is difficult. However, there is a problem that a lot of trouble is required.
[0004]
Further, if the valve body is made of metal, high heat around the outside of the valve body and low heat inside the valve body exchange heat, and there is a possibility that the thermal efficiency of the refrigeration cycle is reduced.
On the other hand, in order to ensure the airtightness of the sliding surface of the valve body, there is also provided one in which a synthetic resin member is arranged on the lower surface of a bowl-shaped valve body. Such a synthetic resin member is usually fixed to a valve body with screws or the like.
[0005]
However, in the case where the synthetic resin member is fixed to the lower surface of the valve body with a screw or the like in this manner, the synthetic resin member is worn out due to repeated sliding of the valve body, and the tip end of the screw projects on the sliding surface. In this case, there is a problem that smooth sliding of the valve body is hindered.
Further, in order to prevent heat transfer of the valve body, a double metal valve body is formed, and a gap is secured inside to prevent heat conduction. However, if the metal valve body is formed in a double form, the weight increases and the smooth operation of the valve body is impaired. Therefore, each metal plate must be formed thin. However, when the metal plate is formed to be thin, the outer periphery of the valve body is at a high pressure and the inside thereof is at a low pressure, so that the valve body may be deformed due to a pressure difference.
[0006]
In order to prevent this deformation, it is conceivable that the metal valve bodies are fixed with rivets to keep them substantially constant.
However, when riveting is performed as described above, there is a problem that the refrigerant is likely to leak from the position where the rivet is driven, and the riveting must be performed so as not to cause deformation.
[0007]
Moreover, even when riveting is performed, a resin sliding member must be arranged on the lower surface of the double metal valve body in order to improve the slidability and airtightness. The above problem similarly arises.
Therefore, in order to solve various problems when the valve body is formed of metal, it has been proposed to form the entire valve body with synthetic resin.
[0008]
As described above, if the entire valve body is formed of synthetic resin, the sliding portion is naturally made of synthetic resin, so that the slidability is improved and sliding is performed smoothly. In addition to this, even if this sliding portion is worn out by repeated use, the metal member such as a screw is not used for fixing as in the related art, so that the metal member is exposed. There is no hindrance to smooth operation.
[0009]
Furthermore, if the entire valve body is made of a synthetic resin, the thermal conductivity is low, and the amount of heat transferred through the valve body is smaller than that made of metal. .
However, even with a valve body made of a synthetic resin, there is still a risk that deformation may occur due to a pressure difference between the inside and the outside of the valve body. Refrigerant is ejected from the deformed portion due to the pressure difference between the inner and outer refrigerant gases, which causes leakage of the refrigerant. In order to solve this problem, it is conceivable to use a hard synthetic resin as the synthetic resin forming the valve body, or to increase the thickness of the valve body, but if a hard synthetic resin is used, In addition, the cost is increased and the sliding performance is reduced. In addition, when the thickness of the valve body is increased, not only the size must be increased, but also the amount of distortion increases when a sudden temperature change occurs, and as a result, the sealing performance of the sliding surface decreases due to thermal deformation. Will be done.
[0010]
Thus, even when the valve body is formed of a synthetic resin, various problems occur as in the case of the metal valve body, and it cannot be said that the valve body is good in all respects.
Therefore, today, as a valve element for a four-way switching valve, which is lightweight, has sufficient strength, has little heat transfer loss, has good sealing properties, and can be operated smoothly even when used for a long time, There is also provided one in which a resin film layer made of a synthetic resin is injection-molded on the outside of a metal core material portion, and further a reinforcing metal pin is inserted. (For example, see Patent Document 1)
[0011]
[Patent Document 1]
JP-A-5-325742 (page 3, FIG. 3)
[0012]
[Problems to be solved by the invention]
By the way, in the four-way switching valve disclosed in Japanese Patent Application Laid-Open No. 5-325742, a reinforcing metal pin is inserted across a hollow portion after injection molding of a resin film layer to form a metal core. It is inserted into the hole formed in the material part and the resin film layer.
[0013]
However, when inserting a metal pin in this way, the length of the pin is formed slightly larger than the end face of the valve body opening, and the diameter of the pin is slightly larger than the hole of the valve body opening, so that the fitting state is improved. Must be strong.
However, if the length and the diameter of the pin are set to be large with respect to the valve body opening end face and the opening hole in this way, a large load is applied to the valve body opening, and therefore, depending on how the force is applied when inserting the pin. In addition, there is a problem that a crack is formed in the resin film layer. Further, under use conditions with a large temperature difference, there is a problem that cracks are enlarged and the valve body may be broken in some cases.
[0014]
In view of such a situation, the present invention has both advantages of a metal valve body and advantages of a resin valve body, and also has a four-sided structure in which the valve body is not cracked or broken. An object of the present invention is to provide a valve body for a switching valve.
Another object of the present invention is to provide a preferable method for manufacturing such a four-way switching valve element.
[0015]
[Means for Solving the Problems]
To achieve the above object, a four-way switching valve valve according to the present invention,
A discharge pipe connected to one side of a closed hollow valve body,
A suction pipe connected to the other side of the valve body,
On each side of the suction tube, two conduits respectively arranged adjacently;
A valve seat provided on an open end surface of the suction pipe and the two conduits in the valve body;
A bowl-shaped valve body having an annular flange on the outer periphery slidably disposed on the upper surface of the valve seat,
By sliding the valve body in one direction or the other direction, the communication state between the suction pipe and the one conduit or between the suction pipe and the other conduit is selectively switched. In a four-way switching valve,
The bowl-shaped valve element has a metal core portion,
A reinforcing metal pin which is inserted across the opening end face of the metal core portion and is fixed integrally to the metal core portion by welding in advance,
After the metal core portion and the reinforcing metal pin are integrated by welding, a resin coating layer integrated by injection molding on the outer surface side and the annular flange portion of the metal core portion, It is characterized by being constituted.
[0016]
According to the valve element for a four-way switching valve having such a configuration, since the core portion is made of metal, sufficient mechanical strength can be obtained, and a metal pin for reinforcing the strength is integrated with the core portion in advance. , It is possible to prevent deformation and the like from occurring. Further, since the lower surface of the valve body serving as the sliding surface is made of synthetic resin, precision processing is easy, airtightness can be sufficiently ensured, and heat conduction can be suppressed low.
[0017]
Therefore, according to such a valve element for a four-way switching valve, even if the valve element is used under a condition with a large temperature difference, or a large pressure difference is generated inside and outside the valve body, cracks are generated, broken, or the valve body is damaged. Can be prevented from being destroyed.
Further, the method for manufacturing a valve element for a four-way switching valve according to the present invention,
Forming a bowl-shaped metal valve body;
A welding step of inserting a reinforcing metal pin across the opening end face of the bowl-shaped metal valve body, and integrally attaching the reinforcing metal pin and the opening end face of the valve body by welding;
By this welding process, the bowl-shaped valve body having the reinforcing pin integrally attached thereto is inserted into a mold, and the resin injected into the mold causes the outer surface side and the annular shape of the metal valve body to be inserted. Forming a resin film layer on the flange portion.
[0018]
According to such a production method of the present invention, since there is no step of inserting a metal pin after injection molding of the synthetic resin film layer, there is no problem such as cracking, breakage, or destruction of the valve body. A valve element for a four-way switching valve can be easily manufactured.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows a valve body for a four-way switching valve manufactured by the manufacturing method according to the present invention.
The valve body 1 of the four-way switching valve is formed in a cylindrical shape, and plugs 2 and 3 are fixed to both ends. A connection port 11d is formed on one side of the valve body 1, and a discharge pipe 5 connected to a compressor 4 such as a compressor is connected to the connection port 11d.
[0020]
In addition, three connection ports 11a, 11b, and 11c are formed on the other side of the valve body 1, and a suction pipe 6 connected to the compressor 4 is connected to the center connection port 11a, and both sides thereof are provided. The conduits 9 and 10 connected to the heat exchangers 7 and 8 are connected to the connection ports 11b and 11c, respectively.
On the other hand, on the upper part of the opening end faces of the suction pipe 6, the conduit 9, and the conduit 10 inserted into the valve body 1, valve seats 11 each having a hole corresponding to the opening are provided.
[0021]
Further, in the valve body 1, a piston 12 is provided between the valve seat 11 and the plug 2, and a piston 13 is provided between the valve seat 11 and the plug 3, and between the piston 12 and the piston 13. , A high-pressure chamber R1 is defined. Further, the piston 12 and the piston 13 are integrally movably connected by a connecting plate 14. The working chamber R2 formed between the piston 12 and the plug 2 and the working chamber R3 formed between the piston 13 and the plug 3 are four-way switched by conduits 2 'and 3', respectively. It is connected to a pilot valve 15. In the present embodiment, the pilot valve 15 has the connection paths shown in FIGS. 2A and 2B. That is, in the connection path shown in FIG. 2A, the connection between the conduit 2 'and the conduit 5' and between the conduit 3 'and the conduit 6' are made, and the connection path shown in FIG. Thus, the connection between the conduit 2 'and the conduit 6' and the connection between the conduit 3 'and the conduit 5' are respectively made.
[0022]
With such a pilot valve 15 interposed between the working chamber R2 and the working chamber R3, in the four-way switching valve of the present embodiment, one of the working chambers R2 and R3 is connected to the conduit 5 ′, The other working chamber is configured to communicate with the suction pipe 6 by the conduit 6 ′.
On the valve seat 11 in the valve body 1, a bowl-shaped valve body 16 having a communication recess 16a and an annular flange 16b is provided. The valve body 16 is loosely fitted in the hole 14a of the connecting plate 14. Therefore, the valve body 16 slides on the valve seat 11 as the pistons 12 and 13 move in the left-right direction in FIG. 1 and closes the low-pressure side connection port 11 a of the suction pipe 6 connected to the compressor 4. And the other heat exchanger side connection ports 11b and 11c are communicated with each other, and the other heat exchanger side connection port is opened to the high pressure chamber R1.
[0023]
As shown in FIGS. 3 (A), (B) and FIG. 4, the bowl-shaped valve body 16 is composed of a metal core portion 20 on the main body side and a resin film layer 40 made of synthetic resin. Thus, when the outer resin film layer 40 is injection-molded with a mold, the space between the outer resin film layer 40 and the core material portion 20 is integrated. In the present invention, before the resin film layer 40 is injection-molded by a mold, the metal pin 23 is inserted near the opening of the metal core portion 20, and both ends are formed on both side walls 21 and 22. They are integrated by welding.
[0024]
Hereinafter, a more detailed manufacturing method of such a valve body 16 will be described.
First, a thin plate-shaped metal material is prepared, and by using a press die from this metal material, as shown in FIG. 5 (A), a bowl-shaped communication recess 20a is formed at the center, and The core member portion 20 having the annular flange portion 20b is formed.
Next, as shown in FIG. 5 (B), both ends of the reinforcing metal pin 23 are inserted into the opening end face, and are integrally attached to the side walls 21 and 22 by welding.
[0025]
When the metal core member 20 and the reinforcing metal pin 23 are integrated by welding in this manner, as shown in FIG. 6A, the gap between the lower mold 24 and the upper mold 28 is reduced. The metal core part 20 described above is arranged. In addition,
At this time, the core portion 20 having an inner surface corresponding to the inner surface shape of the valve body 16 and having the horizontal annular flange portion 20a is mounted by engaging the hole 26 engaging with the projection 25 of the lower mold 24. Place. At this time, the metal pin 23 integrally fixed to the core part 20 is accommodated in a narrow groove 41 formed in the lower mold 24 as shown in FIG. After the lower mold 24 is arranged, the upper mold 28 having the outer shape of the valve body 16 is arranged thereon.
[0026]
When the molds 24 and 28 are assembled in this way, synthetic resin is injected into the cavity 42 from the injection port 29 of the upper mold 28, and after cooling, the upper mold 28 and the lower mold 24 are separated and separated. As a result, as shown in FIG. 3, the valve body 16 in which the synthetic resin film 40 is integrally coated on the outside of the metal core 20 is completed. In addition, the surface of the annular flange portion 20b of the core portion 20 is also covered with the synthetic resin, so that the annular flange portion 16a constituting the sliding portion is formed.
[0027]
As the resin for forming the resin coating layer 40, various resins having heat resistance, pressure resistance and moderate sliding familiarity can be used. For example, PPS (polyphenylene sulfide) resin or PFA (ethylene tetrafluoride ethylene) can be used. -Perfluoroalkoxy ethylene) resin or the like is appropriate, and stainless steel or the like is appropriate for the core portion 20 for reinforcement.
[0028]
As shown in FIG. 1, the four-way switching valve configured as described above is used, for example, when switching the flow of a refrigerant between cooling and heating in a refrigeration system.
At this time, the valve element 16 receives the pressure of the high-temperature refrigerant from the outer periphery and slides smoothly while being pressed against the valve sheet 11. Further, since the metal core portion 20 is integrally provided inside the synthetic resin film layer 40, even if the synthetic resin film layer 40 is thinned, deformation is prevented by the reinforcing effect of the metal core material portion 20. Is done. Therefore, it is possible to smoothly slide the valve body 16 while preventing a decrease in sealing performance due to the deformation, a leakage of the refrigerant gas, and the like.
[0029]
Moreover, since the core portion 20 and the metal pin 23 are integrally fixed in advance by welding, as in the conventional example, an excessive force such as forming a hole is applied to the metal pin to apply the synthetic resin film layer. Since it is not fitted to 40, no crack occurs in the valve body during the manufacturing process. Also, even when a sudden temperature change occurs in the valve body, such as during the defrosting operation of the refrigeration system, there is no possibility of cracking or breakage, and a stable state for a long time. Can be used throughout.
[0030]
As described above, according to the valve element for a four-way switching valve according to the present invention, the reinforcing metal pin 23 is previously integrated with the metal core portion 20 by welding, so that the There is no need to use excessive force to fit the metal pin into the small hole. Therefore, cracks and cracks do not occur by using metal pins as in the related art. Also, even if used under conditions that cause a severe temperature difference, there is no cracking or breakage.
[0031]
【The invention's effect】
As described above, according to the valve element for a four-way switching valve according to the present invention, at the time of manufacturing, the reinforcing metal pin is formed by a hole or a synthetic resin in a core portion formed to have a diameter smaller than the diameter of the metal pin. Since it is not inserted into holes or the like of the coating layer, cracks do not occur during the manufacturing process. Further, even if used under the condition that a severe temperature difference is generated, there is no crack from the time of manufacture, so that the crack does not expand and is damaged or broken.
[0032]
Furthermore, since the valve body is made of a synthetic resin and has a low thermal conductivity, heat exchange between the high-temperature refrigerant and the low-temperature refrigerant through the valve body reduces the efficiency of the refrigeration cycle. Further, when the valve body slides, the sliding surface is made of a synthetic resin, so that the valve body can be smoothly operated.
Furthermore, since the strength of the synthetic resin film layer is supplemented by the metal core portion, sufficient strength can be exerted even when the thickness of the entire valve body is reduced, contributing to miniaturization of the entire valve. . In addition, even when the temperature inside the valve body changes suddenly as in the case of defrosting, and the synthetic resin film layer is going to deform due to this, the deformation is caused by the metal core part being installed integrally. It does not occur, nor does the peeling of the resin film layer occur.
[0033]
Furthermore, in the manufacturing method according to the present invention, since the metal pin is integrated with the core portion in advance by welding, dimensional errors and the like hardly occur. Therefore, the manufacturing method of the present invention is easy to manufacture. Further, even under a use condition in which a temperature difference is severe, the welded portion does not peel off.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view when a four-way switching valve manufactured according to an embodiment of the present invention is used in a refrigeration cycle.
2 (A) is a schematic diagram showing one connection path of a pilot valve used in the refrigeration cycle of FIG. 1, and FIG. 2 (B) shows another connection path of the pilot valve. It is a schematic diagram.
FIG. 3A is a cross-sectional view of a four-way switching valve body manufactured in this embodiment, and FIG. 3B is a bottom view of the four-way switching valve body manufactured in this embodiment. is there.
FIG. 4 is a sectional view taken along line AA in FIG. 3;
FIG. 5 (A) is a front view of a core portion formed by pressing a plate-shaped metal material by pressing or the like, and FIG. 5 (B) is a reinforcing metal pin welded to the metal core portion. It is a front view of the core material at the time.
FIG. 6A is an exploded cross-sectional view when a metal core part is inserted into a mold, and FIG. 6B is a state in which the resin is injected by incorporating the core part into the mold. It is a sectional view before.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Valve main body 4 Compressor 5 Discharge pipe 6 Suction pipe 9 Conduit 10 Conduit 11 Valve seat 11a Connection port 11b Connection port 11c Connection port 16 Valve body 16a Ring flange 20 Core part 20b Ring flange 23 Reinforcement metal pin 24 Below Mold 28 Upper mold 40 Resin film layer

Claims (2)

A discharge pipe connected to one side of a closed hollow valve body,
A suction pipe connected to the other side of the valve body,
On each side of the suction tube, two conduits respectively arranged adjacently;
A valve seat provided on an open end surface of the suction pipe and the two conduits in the valve body;
A bowl-shaped valve body having an annular flange on the outer periphery slidably disposed on the upper surface of the valve seat,
By sliding the valve body in one direction or the other direction, the communication state between the suction pipe and the one conduit or between the suction pipe and the other conduit is selectively switched. In a four-way switching valve,
The bowl-shaped valve element has a metal core portion,
A reinforcing metal pin which is inserted across the opening end face of the metal core portion and is fixed integrally to the metal core portion by welding in advance,
After the metal core portion and the reinforcing metal pin are integrated by welding, a resin coating layer integrated by injection molding on the outer surface side and the annular flange portion of the metal core portion, A valve element for a four-way switching valve, comprising: Forming a bowl-shaped metal valve body;
A welding step of inserting a reinforcing metal pin across the opening end face of the bowl-shaped metal valve body, and integrally attaching the reinforcing metal pin and the opening end face of the valve body by welding;
By this welding process, the bowl-shaped valve body having the reinforcing pin integrally attached thereto is inserted into a mold, and the resin injected into the mold causes the outer surface side and the annular shape of the metal valve body to be inserted. Forming a resin film layer on the flange portion. A method for manufacturing a valve element for a four-way switching valve, comprising:

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