JP2001091077A - Refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerating machine that suppresses manufacturing cost, and can improve reliability. SOLUTION: At both the ends of a cylinder, high- and low-temperature ends are demarcated. The cylinder is formed by an iron-based alloy. Space at the sides of the high and low-temperature ends in the cylinder is interlocked by a gas channel. A coldness-accumulation material is filled in the gas channel, and heat exchange is made between a refrigerant gas flowing inside and the coldness-accumulation material. A cold stage being formed by the iron based alloy is welded to the low-temperature end of the cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator, and more particularly, to a closed type closed cycle refrigerator.

[0002]

2. Description of the Related Art The prior art will be described by taking a Stirling refrigerator as an example. Stirling refrigerators are basically
It is configured to include a cylinder, displacer, cold stage, and cylinder holder. The displacer is inserted into the cylinder and defines a cold side cavity and a hot side cavity at both ends. In the displacer, a gas flow path that connects the low-temperature side cavity and the high-temperature side cavity is formed. The gas flow path is filled with a cold storage material.

[0003] The cold stage is attached to the cold end of the cylinder, and the cylinder holder is attached to the hot end of the cylinder. The cylinder is made of stainless steel or the like having a low thermal conductivity in order to suppress the flow of heat from the high-temperature end to the low-temperature end. The cold stage is formed of copper or the like having a high thermal conductivity in order to efficiently cool an object to be cooled. The cylinder holder is also formed of copper or the like having a high thermal conductivity in order to efficiently release generated heat.

[0004] The cold stage and the cylinder, and the cylinder holder and the cylinder are joined by brazing or soldering.

[0005] The displacer is elastically supported in the cylinder axial direction by an elastic member outside the cylinder. The elastic member is disposed in an airtight space defined by the cylinder holder and the pressure vessel. The pressure vessel and the cylinder holder are fastened with bolts with a soft metal gasket or metal O-ring sandwiched between the contact portions of the two.

[0006]

When performing brazing or soldering, the joint portion is heated to 400 to 1000 ° C. The thickness of the cylinder is usually about 0.2 to 0.5 mm in order to suppress heat from entering the high-temperature end to the low-temperature end. Thus, 400 to 100 for thin cylinders
When heat of about 0 ° C. is applied, distortion during cylinder processing is released and deformed. In particular, when performing brazing in a furnace, since the entire part is exposed to a high-temperature environment, distortion may occur in the entire part. For this reason, after joining, it is necessary to perform correction by reamer cutting, lapping, etc. again. This correction leads to increased costs. Further, gas leakage may occur due to internal corrosion due to residual flux.

[0007] When the thermal cycle is repeated, bolts for fastening the pressure-resistant container and the cylinder holder may be loosened, or the gasket itself may be displaced to cause gas leakage.

[0008] An object of the present invention is to provide a refrigerator capable of suppressing manufacturing costs and increasing reliability.

[0009]

According to one aspect of the present invention, a high-temperature end and a low-temperature end are defined, a cylinder formed of an iron-based alloy, a space on the high-temperature end side and a low-temperature end side in the cylinder. Refrigeration having a gas flow path filled with a regenerator material that exchanges heat with a refrigerant gas flowing therethrough, and a cold stage welded to the low-temperature end of the cylinder and formed of an iron-based alloy. Machine is provided.

By locally heating the welded portion,
The cylinder and the cold stage can be joined. Since the entire cylinder is not placed in a high-temperature environment, thermal distortion of the cylinder can be suppressed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, an embodiment of the present invention will be described by taking a Stirling refrigerator as an example. A cold stage 2 is attached to one end (low temperature end) of the cylinder 1. The cylinder 1 and the cold stage 2 are formed of an iron-based alloy, for example, stainless steel or Kovar (iron-nickel-cobalt alloy). The cold stage 2 has a cylindrical portion that matches the inner peripheral surface of the cylinder 1. This cylindrical portion is fitted in the cylinder 1 and both are welded. For example, electron beam welding is used for welding the two. By fitting the cylindrical portion of the cold stage 2 into the cylinder 1, deformation of the cylinder 1 during welding can be prevented.

A displacer 4 is inserted into the cylinder 1. The displacer 4 includes a cylindrical member 4a, a low-temperature sliding member 4b, and a high-temperature sliding member 4c. The cylindrical member 4a is formed of stainless steel, and the low-temperature side sliding member 4b and the high-temperature side sliding member 4c are stainless steel plugs, and polytetrafluoroethylene (PTFE) is adhered to the sliding surface with the cylinder 1. Have been. The low temperature side sliding member 4b closes the low temperature end of the cylindrical member 4a, and the high temperature side sliding member 4c closes the high temperature end of the cylindrical member 4a. These members are fixed to each other by welding. The cold storage material 15 is filled in the internal space 5 of the cylindrical member 4a. The cold storage material 15 is formed by stacking, for example, a stainless steel mesh.

The cold side cavity 10 is defined by the displacer 4, the cylinder 1 and the cold stage 2. A through-hole 4d is formed in the low-temperature side sliding member 4b to allow the space in the cylindrical member 4a to communicate with the low-temperature side cavity 10.

A cylindrical inner peripheral surface 3 is provided on the cylinder holder 3.
Through holes defining a, 3b, and 3c are formed. The cylinder holder 3 is formed of an iron-based alloy, for example, stainless steel or Kovar. Inner peripheral surfaces 3a, 3b,
And 3c are arranged in this order in the axial direction of the through hole, and the diameter increases in this order. A part on the high temperature side of the cylinder 1 is inserted into the inner peripheral surface 3 a of the through hole of the cylinder holder 3. The high temperature end of the cylinder 1 is
And 3b.

The area near the high temperature end of the cylinder 1 is widened so that the diameter of the high temperature end is slightly larger than the diameters of the other parts. The end of the inner peripheral surface 3a on the inner peripheral surface 3b side has a shape that matches this spread. The end surface on the high temperature side of the cylinder 1 and the periphery of the end of the inner peripheral surface 3a are welded. A welding lip 7 is formed at an end of the inner peripheral surface 3a.

A high temperature side sealing member 6 is inserted into the inner peripheral surface 3b of the through hole of the cylinder holder 3. The high-temperature side cavity 11 is defined by the high-temperature side sealing member 6, the cylinder 1, and the displacer 4. The high-temperature side sealing member 6 has a flange portion that matches the step between the inner peripheral surfaces 3b and 3c. This flange portion is fixed to the cylinder holder 3 by bolts. The O-ring 8 ensures airtightness of a contact portion between the step surface between the inner peripheral surfaces 3b and 3c and the flange portion.

A connecting rod 20 is connected to the high-temperature-side sliding member 4c, passes through the high-temperature-side sealing member 6, and extends to the outside of the cylinder 1. The stainless steel plug and the connecting rod 20 of the high temperature side sliding member 4c may be manufactured by integral molding, or both may be separately molded and welded. The penetrating part forms a clearance seal. High temperature side sliding member 4
The gas flow path 12 is formed in c. Gas flow path 12
Makes the space 5 in the cylindrical member 4 a communicate with the high-temperature side cavity 11. The gas flow path 12, the space 5 in the cylindrical member 4a, and the through hole 4d form a gas flow path that connects the low-temperature side cavity 10 and the high-temperature side cavity 11.

The leaf springs 30 and 31 elastically support the displacer 4 via the connecting rod 20 in the cylinder axial direction. Each of the leaf springs 30 and 31 is configured by laminating a plurality of disks having a circular through hole in the center. The disk is provided with a slit in the radial direction. The connecting rod 20 is inserted into the through holes of the leaf springs 30 and 31. An annular holding member 21 and a cylindrical spacer 22 fitted into the connecting rod 20 are fixed with the peripheral portion of the through hole of the leaf spring 30 interposed therebetween. The spacer 22 and the lock nut 23 fitted to the connecting rod 20 are fixed with the peripheral portion of the through hole of the leaf spring 31 interposed therebetween.

The outer periphery of the leaf spring 30 is
Is sandwiched between an end surface of the inner peripheral surface 3c connected to the opening and the cylindrical spacer 24. By fixing the spacer 24 to the cylinder holder 3 with bolts,
The outer periphery of the leaf spring 30 is fixed to the cylinder holder 3.
The outer periphery of the leaf spring 31 is sandwiched between the spacer 24 and the holding member 25. The leaf spring 31 is fixed to the cylinder holder 30 by fixing the pressing member 25 to the spacer 24 with a bolt.

The pressure vessel 40 and the cylinder holder 3 define an airtight space in which the leaf springs 30 and 31 are accommodated. The pressure-resistant container 40 is a cylindrical container formed of an iron-based alloy, such as stainless steel or Kovar, and having one end closed. The pressure vessel 40 is welded to the cylinder holder 3. A welding lip 41 is provided on the welding portion of the cylinder holder 3.
Are formed.

A flange 3d is formed on an end surface of the cylinder holder 3 which is continuous with the inner peripheral surface 3a. Flange 3d
Is mounted on a vacuum vessel and holds the cold stage 2 in the vacuum vessel.

High temperature side sealing member 6 and cylinder holder 3
In addition, a gas flow path 13 communicating with the high temperature side cavity 11 is provided. The gas flow path 13 opens on the outer peripheral surface of the cylinder holder 3. The capillary tube 35 made of stainless steel
It is welded to the cylinder holder 3 so as to communicate with the gas passage 13. A welding lip 42 is formed at a welding portion of the cylinder holder 3.

The capillary tube 35 is connected to the gas compressor 3
6 is connected. The gas compressor 36 periodically repeats supply and recovery of the compressed refrigerant gas. The displacer 4 reciprocates in synchronization with the supply and recovery of the refrigerant gas,
Cold occurs in the low-temperature side cavity 10.

In the above embodiment, the cold stage 2 and the cylinder 1 and the cylinder 1 and the cylinder holder 3 are welded. For this welding, for example, electron beam welding is used. Electron beam welding is performed by local heating,
The calorie itself is also small. For this reason, distortion of the cylinder 1 at the time of joining can be suppressed. In order to weld two parts, both need to be formed of an iron-based alloy. In order to obtain a good welded structure, the iron content is preferably 50% by weight or more.

In the above embodiment, electron beam welding
Although the case where the iron-based alloys are welded has been described, other welding methods may be used. For example, laser beam welding, tungsten inert gas arc welding, or the like can be used.

The welding between the cylinder 1 and the cylinder holder 3 is performed at the high-temperature end of the cylinder 1. For this reason, heat at the time of welding is not applied to the region where the displacer 4 reciprocates. Therefore, distortion of a portion of the cylinder 1 that slides with the displacer 4 can be suppressed.

The end on the high temperature side of the cylinder 1 has a widened shape. Therefore, even if the welded portion shrinks due to thermal strain and the inner diameter of the portion is reduced, the insertion of the displacer 4 into the cylinder 1 is not hindered.

Cold stage 2 and cylinder holder 3
Is formed of an iron-based alloy having a lower thermal conductivity than copper, and there was a concern that the refrigerating performance would be reduced.However, according to the experiments performed by the present inventors, the refrigerating performance was hardly reduced. . By forming these parts with an iron-based alloy,
It has become possible to adopt a welding structure.

In the above embodiment, the pressure vessel 40 is welded to the cylinder holder 3. For this reason, even if the heat cycle is repeated, the deterioration of the joint portion is small, and gas leakage and the like can be prevented. Thereby, the reliability of the refrigerator can be improved.

Since the flange 3d of the cylinder holder 3 is formed of an iron-based alloy, the cylinder holder 3 can be welded to the vacuum vessel. By employing the welding structure, the degree of vacuum in the vacuum vessel can be easily increased, and the vacuum holding time can be lengthened.

In the above embodiment, the Stirling refrigerator has been described as an example, but the welding structure may be applied to other hermetic refrigerators. For example, the cold stage of the pulse tube refrigerator may be welded to the low temperature end of the pulse tube or the low temperature end of the regenerator. Further, the cold stage of the GM refrigerator may be welded to the low temperature end of the cylinder.

The present invention has been described in connection with the preferred embodiments.
The present invention is not limited to these. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0033]

As described above, according to the present invention,
By making the joint between the cylinder and the cold stage a welded structure, distortion of the cylinder during joining can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a Stirling refrigerator according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder 2 Cold stage 3 Cylinder holder 4 Displacer 5 Cavity 6 High-temperature side sealing member 7 Welding lip 8 O-ring 10 Low-temperature side cavity 11 High-temperature side cavity 12, 13 Gas flow path 15 Cold storage material 20 Connecting rod 21 Suppression member 22 Spacer 23 Lock Nut 24 Spacer 25 Pressing member 30, 31 Leaf spring 35 Capillary tube 36 Gas compressor 40 Pressure vessel 41 Welding lip

Claims (4)

[Claims] 1. A refrigerant gas having a high-temperature end and a low-temperature end defined therein, formed of an iron-based alloy, and connecting a high-temperature end space and a low-temperature end space in the cylinder to flow through the cylinder. A refrigerator having a gas flow path filled with a regenerator material that performs heat exchange with a cold stage welded to a low-temperature end of the cylinder and formed of an iron-based alloy. 2. The refrigerator according to claim 1, further comprising a cylinder holder welded to a high temperature end side of the cylinder, formed of an iron-based alloy, and holding the cylinder by attaching it to another member. 3. A displacer which is inserted into the cylinder and divides a space in the cylinder into a space on a low-temperature end side and a space on a high-temperature end side, wherein the gas flow path is provided in the displacer. The refrigerator according to claim 2, wherein the refrigerator is formed. 4. A connecting rod connected to a high-temperature end of the displacer and led out of the cylinder; an elastic member for elastically supporting the connecting rod in a cylinder axial direction; A pressure-resistant container that accommodates a portion led out of the cylinder and the elastic member and makes the inside an airtight space, wherein the pressure-resistant container is formed of an iron-based alloy and is welded to the cylinder holder. The refrigerator according to claim 3, wherein