Expansion valve

Abstract

To provide an expansion valve capable of enhancing manufacturing efficiency of a body and yield from material, thereby reducing manufacturing costs thereof. According to the expansion valve of the present invention, a body is formed by die casting an aluminum alloy, and hence even when the body has a complicated shape, it is possible to easily manufacture the body. Further, even a valve seat, which is difficult to form by extrusion, can be formed integrally with the body, and hence the manufacturing efficiency of the body can be enhanced. Furthermore, component parts, such as the valve seat and the like, conventionally formed by cutting, are also formed integrally with the body by die casting, and hence it is possible to enhance yield from material to reduce manufacturing costs of the expansion valve.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS, IF ANY [0001] This application claims priorities of Japanese Application No. 2005-060795 filed on Mar. 4, 2005, entitled “EXPANSION VALVE”, No. 2005-212618 filed on Jul. 22, 2005, entitled “EXPANSION VALVE”, No. 2005-356373 filed on Dec. 9, 2005, entitled “EXPANSION VALVE” and No. 2006-012969 filed on Jan. 20, 2006, entitled “EXPANSION VALVE”. BACKGROUND OF THE INVENTION [0002] (1) Field of the Invention [0003] The present invention relates to an expansion valve which is disposed in a refrigeration cycle, for throttling and expanding refrigerant introduced from an upstream side and delivering the refrigerant to a downstream side. [0004] (2) Description of the Related Art [0005] In general, a refrigeration cycle for an automotive air conditioner comprises a compressor that compresses refrigerant circulating through the refrigeration cycle, a condenser that condenses the compressed refrigerant, a receiver that stores the refrigerant circulating...

AI Technical Summary

Benefits of technology

[0014] The present invention has been made in view of the problems, and an object thereof is to enhance the manufacturing efficiency of a body of an expansion valve and yield from material, thereby reducing manufacturing costs of the expansion valve.

Problems solved by technology

However, the cutting process takes a long machining time period and is low in yield, resulting in increased manufacturing costs of the expansion valve.

This makes it impossible to apply the extrusion to the formation of the first passage with which a valve seat as a component part of a valve section is integrally formed in an intermediate portion thereof.

Further, although at ends of the first and second passages, there are formed sealing surfaces of sealing members which are interposed for connection of pipes connected to the compressor, the receiver, and the evaporator, the sealing surfaces cannot be formed by extrusion molding, since the end portions are diametrically expanded.

Therefore, as for these portions, there is still no other way but employ machining by cutting, which makes it impossible to sufficiently reduce the amount of used materials and enhance manufacturing efficiency.

Further, when the second passage is formed by the hollow extrusion, and then the ends thereof are to be cut by a lathe, for example, it is not easy to cause the axis of the passage during extrusion molding and the axis of the rotating shaft during a cutting process to coincide with each other.

Therefore, for example, when an attempt is made to form a sealing portion by a tool, such as a drill, the axis of the tool can be eccentric with respect to the axis of the passage, and eccentric load can act on the tool and the body during machining, which can cause machining problems.

Further, although it is contemplated to employ a method of manufacturing the body by injection molding of a resin material, resin materials are inferior to metal materials in rigidity and strength, and produce larger flow noises of refrigerant.

Moreover, a resin material once cured is difficult to plastically deform, and even when the valve section is about to be coined in accordance with the shape of the valve element, the resin material does not easily conform to dies, which is liable to cause fracture during machining.

This makes it necessary to perform insert molding of a valve section separately formed of a metal, during injection molding, which makes the manufacturing process cumbersome.

It should be noted that the above-described problems are not only suffered by the temperature expansion valve but also by electromagnetic expansion valves and the like.

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