JP2004239565A - Cryogenic refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily form a spiral gas passage between a displacer and a cylinder. <P>SOLUTION: Spiral grooves 32, 50, 60 are formed on the outer surface of the displacer 16, and seal members 40, 52 are inserted in the grooves, thereby forming the gas passage 14 secondarily between the seal members. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cryogenic refrigerator in which a spiral gas flow path is formed between a displacer sliding in a cylinder and the cylinder, and more particularly to a Gifford McMahon cycle having a minimum temperature of 4K or less. The present invention relates to a cryogenic refrigerator suitable for use in a refrigerator (referred to as a 4K-GM refrigerator) and capable of easily forming a spiral gas flow path between a displacer and a cylinder.
[0002]
[Prior art]
A GM refrigerator, a Stirling cycle refrigerator, and the like are known as a regenerator type cryogenic refrigerator having a regenerator containing a regenerator material using a gas refrigerant such as helium. As shown in Patent Literature 1, Patent Literature 2, and Patent Literature 3, an internal gas flow sliding in a cylinder 12 is shown in FIG. 1 in this regenerator type cryogenic refrigerator. Some have a displacer 16 in which a passage 20 is filled with a cold storage material 18 and a spiral gas flow path 14 formed between the displacer 16 and the cylinder 12. In the figure, reference numeral 22 denotes an expansion space in the cylinder 12.
[0003]
In such a displacer 16, as shown in FIG. 2, the spiral gas flow path 14 is conventionally formed with a groove 24 by machining as shown in FIG. The coating member 26 made of an abrasion resin was formed.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 7-324831 [Patent Document 2]
JP 2000-146335 A [Patent Document 3]
JP 2000-292022 A
[Problems to be solved by the invention]
However, when the spiral gas flow path 14 is formed only by machining, it is necessary to machine deeply in order to secure a sufficient cross section, and there is a problem that the machining is time-consuming and costly. Was.
[0006]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has as its object to easily form a spiral gas flow path between a displacer and a cylinder.
[0007]
[Means for Solving the Problems]
The present invention provides a cryogenic refrigerator in which a spiral gas flow path is formed between a displacer sliding in a cylinder and the cylinder, wherein a spiral groove formed on an outer peripheral surface of the displacer; This has solved the above-mentioned problem by having a sealing member inserted into the groove, and forming a spiral gas flow path by the sealing member.
[0008]
Further, the thermal expansion coefficients of the displacer and the cylinder are made substantially the same.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0010]
As shown in FIGS. 3 (detailed view of displacer), FIG. 4 (overall schematic view in a state of being assembled in a cylinder), and FIG. As shown in detail in FIG. 5, a rectangular groove 32 having a rectangular cross section is formed on the outer peripheral surface of the cylindrical member 30 constituting the displacer 16, and the rectangular groove 32 has an abrasion resistance and a substantially rectangular cross section. The sealing member 40 is fixed.
[0011]
Thereby, the spiral gas flow path 14 is formed secondarily between the seal members 40.
[0012]
The cylindrical member 30 is formed of, for example, the same material as the cylinder 12 (for example, stainless steel or resin material), or a resin material having a thermal expansion coefficient substantially equal to that of the cylinder 12. Thereby, the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the displacer can be kept small regardless of the temperature change.
[0013]
As the seal member 40, for example, a fluororesin can be used. Both ends of the seal member 40 are fixed, for example, by bonding or by inserting tips into small holes formed at both ends of the square groove 32.
[0014]
In the figure, 34 is an opening forming a gas flow passage formed on the side surface of the cylindrical member 30, 42 is a felt plug, 44 is a whole net, and 46 is the cylindrical shape for fixing the cold storage material 18. A lid member 48 that is connected to both ends of the section 30 is a gas flow path formed in the high-temperature side lid member.
[0015]
The other points are the same as in the above-mentioned conventional example, and the description is omitted.
[0016]
In the first embodiment, the square groove 32 is formed on the outer peripheral surface of the displacer 16 and the seal member 40 having a substantially rectangular cross section is inserted therein. However, the shape of the groove and the seal member is not limited to this. Not limited. For example, as in the second embodiment shown in FIG. 6 (overall schematic view) and FIG. 7 (enlarged view of the part VII in FIG. 6), a sealing member 52 having a circular cross section is inserted into a triangular groove 50 having a triangular cross section. As shown in FIG. 8 (an overall schematic diagram) and FIG. 9 (an enlarged view of the portion IX in FIG. 8), the second embodiment is formed in a circular groove 60 having a semicircular cross section. Similarly, the sealing member 52 having a circular cross section can be inserted.
[0017]
This embodiment is particularly suitable for use in a 4K-GM refrigerator, but the application of the present invention is not limited to this. For example, the present invention is similarly applicable to other regenerator refrigerators such as a Stirling cycle refrigerator. Can be used.
[0018]
【The invention's effect】
According to the present invention, a spiral gas flow path between a displacer and a cylinder can be easily formed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a regenerator of a conventional cryogenic refrigerator proposed by the applicant in Japanese Patent Application Laid-Open No. 7-324831. FIG. FIG. 4 is a cross-sectional view showing a specific configuration of a displacer according to one embodiment; FIG. 4 is an overall schematic view similarly showing a state where the displacer is incorporated in a cylinder; FIG. 5 is an enlarged view of a portion V in FIG. 4 FIG. FIG. 7 is an enlarged view of a VII part in FIG. 6; FIG. 8 is an overall schematic view showing a structure of a third embodiment of the present invention; FIG. 9 is an enlarged view of an IX part in FIG. Description】
12 ... Cylinders 14, 20, 48 ... Gas flow path 16 ... Displacer 18 ... Cooling material 30 ... Cylindrical member 32 ... Square groove 40, 52 ... Seal member 50 ... Triangle groove 60 ... Round groove

Claims (2)

In a cryogenic refrigerator in which a spiral gas flow path is formed between a displacer sliding in a cylinder and the cylinder,
A spiral groove formed on the outer peripheral surface of the displacer,
Having a sealing member inserted into the groove,
A cryogenic refrigerator, wherein a spiral gas flow path is formed by the seal member. A cryogenic refrigerator, wherein the displacer and the cylinder have substantially the same coefficient of thermal expansion.

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