Piston assembly of cooler

Abstract

There is provided a piston assembly configured to include: a hollow cylinder-shaped magnet sleeve having a magnet(s) bonded on external circumferential surface thereof; a hollow cylinder-shaped piston inserted into a hollow space of the magnet sleeve; and a hollow disc-shaped ring fixed to the piston by a shrink fitting process, and welded to the magnet sleeve which is made of the same material as the ring so as to obtain a configuration of the piston assembly in which the magnet sleeve and the piston are coupled to each other.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a piston assembly in which a piston is coupled with an armature of a linear motor, and more particularly, to a piston assembly of a cooler configured by welding a stainless steel ring or inserting a fixing member for welding such that the fixing member is fixed to a bent portion of an armature of a linear motor to improve the convenience of the coupling process of the piston and the armature of the linear motor. [0003] 2. Description of the Related Art [0004] Generally, a cooler is an apparatus for generating cooling effect through the processes of compression, expansion, etc. of working fluid, such as helium, hydrogen, etc. FIG. 1 is a schematic view of a generalized cooler. [0005] As shown in FIG. 1, a cooler 1 includes a driving part 100 for compressing coolant gas through linear reciprocating movement of a piston 140 by electromagnetic mutual interaction of a linear motor 130 int...

AI Technical Summary

Benefits of technology

[0030] An object of the present invention is to provide a piston assembly for simplifying the coupling process of the magnet sleeve and the piston compared with the conventional case by welding a linear motor armature and a stainless steel ring, the armature being made of the same material as the ring, instead of using small bolts or screws in the convention case.

[0031] In addition, the coupling process of the magnet sleeve and the piston of the present invention is simplified because a fixing member is inserted into a bolt-inserting hole formed on the flange part of the piston, and the fixing member is weld and fixed to a bent portion of the magnet sleeve by applying electric current.

[0032] As a result, the time for coupling and assembly is reduced due to the simplified coupling process. Accordingly, another object of the invention is to save the production costs and improve the productivity.

Problems solved by technology

However, the coupling method as above is very unconvenient and time-consuming because the coupling method involves the processes of inserting a plurality of small bolts 143 into the bolt-inserting holes 142, 146 formed on the flange part 141 of the piston 140 and the bent portion 145 of the armature 130b respectively one by one and also fastening the bolts 143 with nuts 144 one by one inside a small box such as the glove box with rubber gloves on.

In addition, it is difficult to fix the nut 144 to the bolt 143 inserted into the external circumferential surface because the sleeve is long and deep.

Therefore, the conventional coupling method in the piston assembly provides disadvantages in reducing operational efficiency and production yield due to difficult and inconvenient screw-coupling process of the armature 130b and the piston 140.

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