JP2019194505A - Regenerator and cryogenic refrigerator - Google Patents

Abstract

To restrain a decrease in refrigerating performance of a cryogenic refrigerator caused by a gap between a regenerative material and a container.SOLUTION: A regenerator 18 of a cryogenic refrigerator comprises: a regenerative pipe 26 comprising a regenerative material 30, and a regenerative material container 32 filled with the regenerative material 30 and extending in an axial direction A; and a regenerative pipe tightening structure 28 for tightening the regenerative pipe 26 from the outside radially so as to reduce a gap in a radial direction B between the regenerative material 30 and the regenerative material container 32. The regenerative pip tightening structure 28 may comprise a ring-shaped clamp member 38 extending in a circumferential direction C along an outer surface of the regenerative material container 32.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a regenerator and a cryogenic refrigerator having the regenerator.

  Cryogenic refrigerators such as pulse tube refrigerators, Stirling refrigerators, and Gifford-McMahon (GM) refrigerators generally include a regenerator having a regenerator material and a container for storing the regenerator material.

JP2015-230131A

  A gap may be generated between the cool storage material and the container due to various factors, for example, expansion and deformation of the container due to the refrigerant gas filling pressure, thermal contraction of the cool storage material due to cooling, manufacturing tolerances, and the like. When such a gap occurs in the regenerator, the refrigerant gas passes therethrough and the refrigerant gas passing through the regenerator material decreases. The efficiency of heat exchange between the regenerator material and the refrigerant gas decreases, and as a result, the refrigeration performance of the cryogenic refrigerator decreases.

  If the dimensional difference (so-called fit) between the cold storage material and the container is reduced, the above-described gap may be reduced or eliminated. However, the operation of filling the container with the cold storage material in the manufacturing process can be difficult. Alternatively, if a container having a large thickness is used, expansion deformation due to the refrigerant gas filling pressure is reduced, and a gap generated by the expansion of the container is reduced. However, during operation of the cryogenic refrigerator, one end of the regenerator is on the high temperature side and the other end is on the low temperature side, so the container wall becomes a heat transfer path. As the wall thickness of the container increases, the amount of heat that enters from the high temperature side to the low temperature side also increases, which may affect the refrigeration performance of the cryogenic refrigerator.

  One of the exemplary purposes of an aspect of the present invention is to suppress a decrease in the refrigerating performance of the cryogenic refrigerator caused by a gap between the cold storage material and the container.

  According to an aspect of the present invention, the regenerator of the cryogenic refrigerator includes a regenerator material, a regenerator tube that is filled with the regenerator material and extends in the axial direction, the regenerator material, and the regenerator material. A cold storage tube tightening structure for tightening the cold storage tube from the outside in the radial direction so as to reduce a radial clearance between the cold storage material container and the cold storage material container.

  According to an aspect of the present invention, a cryogenic refrigerator including the above-described regenerator is provided.

  Note that any combination of the above-described constituent elements and the constituent elements and expressions of the present invention replaced with each other among methods, apparatuses, systems, and the like are also effective as an aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of the refrigerating performance of a cryogenic refrigerator resulting from the clearance gap between a cool storage material and a container can be suppressed.

It is a figure showing roughly a cryogenic refrigerator concerning an embodiment. It is the schematic which shows DD cross section of the expander of the cryogenic refrigerator shown by FIG. It is the schematic which shows the cool storage of the cryogenic refrigerator which concerns on a comparative example. It is the schematic which shows the other example of the cool storage pipe fastening structure which can be applied to the cryogenic refrigerator which concerns on a certain embodiment. It is the schematic which shows the other example of the cool storage pipe fastening structure which can be applied to the cryogenic refrigerator which concerns on a certain embodiment. It is the schematic which shows the cool storage of the cryogenic refrigerator which concerns on a certain embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description and drawings, the same or equivalent components, members, and processes are denoted by the same reference numerals, and redundant descriptions are omitted as appropriate. The scales and shapes of the respective parts shown in the drawings are set for convenience in order to facilitate explanation, and are not limitedly interpreted unless otherwise specified. The embodiments are illustrative and do not limit the scope of the present invention. All features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  FIG. 1 schematically illustrates a cryogenic refrigerator 10 according to an embodiment. The cryogenic refrigerator 10 is configured as a Stirling pulse tube refrigerator, and includes a pressure vibration source 12, a connection pipe 14, and an expander 16 that is also called a cold head. The expander 16 includes a regenerator 18, a cooling stage 20, a pulse tube 22, and a phase controller 24. The expander 16 has a so-called in-line type or linear type configuration in which the regenerator 18 and the pulse tube 22 are connected to each other in a coaxial and series manner. For the sake of understanding, the axial direction, radial direction, and circumferential direction of the expander 16 (that is, the regenerator 18 and the pulse tube 22) are shown by arrows A, B, and C, respectively.

  For simplicity, the cryogenic refrigerator 10 is shown as a single-stage pulse tube refrigerator, but in some embodiments, the cryogenic refrigerator 10 is configured as a two-stage pulse tube refrigerator. It is also possible to do.

  As the refrigerant gas (also called working gas) of the cryogenic refrigerator 10, helium gas is typically used. However, the present invention is not limited to this, and any other suitable gas can be used as the refrigerant gas. The refrigerant gas is filled and enclosed in the cryogenic refrigerator 10.

  In the cryogenic refrigerator 10, the pressure oscillation of the refrigerant gas is induced in the pulse tube 22 by the operation of the pressure oscillation source 12, and the pulse tube 22 has an appropriate phase delay in synchronization with the pressure oscillation by the action of the phase control unit 24. It is designed so that the displacement vibration of the refrigerant gas, that is, the reciprocation of the gas piston occurs in the interior. The movement of the refrigerant gas that periodically reciprocates up and down in the pulse tube 22 while maintaining a certain pressure is often referred to as a “gas piston” and is often used to explain the behavior of the pulse tube refrigerator. When the gas piston is at or near the high temperature end of the pulse tube 22, the refrigerant gas expands at the low temperature end of the pulse tube 22 to generate cold.

  By repeating such a refrigeration cycle (for example, specifically, a reverse Stirling cycle), the cryogenic refrigerator 10 can cool the cooling stage 20 to a desired cryogenic temperature. Therefore, the cryogenic refrigerator 10 can cool an object to be cooled, which is installed on the cooling stage 20 or thermally coupled to the cooling stage 20 via an appropriate heat transfer member, to an extremely low temperature.

  As an example, the object to be cooled may be a detection element that detects infrared rays, submillimeter waves, X-rays, or other electromagnetic waves. Such a detection element may be a component of an observation device used for astronomical observation. Along with the observation apparatus having such an electromagnetic wave detection element, the cryogenic refrigerator 10 may be mounted on a space machine such as an artificial satellite. Alternatively, the cryogenic refrigerator 10 may be mounted on a ground facility provided with such an observation device. Alternatively, the cryogenic refrigerator 10 may be mounted on a spacecraft or ground facility together with, for example, a superconducting device or other device in which a cryogenic environment is desired.

  The pressure vibration source 12 is configured as a so-called opposed two-cylinder linear compressor having two cylinders 12a arranged coaxially so as to face each other. Each cylinder 12a accommodates a piston 12b and a linear actuator 12c that vibrates the piston 12b in the axial direction. The vibration direction of the piston 12 b is different from the axial direction of the expander 16. The piston 12b is elastically supported by the cylinder 12a through a leaf spring or an elastic support member, also called a flexure bearing 12d, so that the displacement in the radial direction and the circumferential direction is restricted while being displaced in the axial direction. The cylinder 12a supports the linear actuator 12c in a fixed manner. A compression chamber 12e is formed between the cylinder 12a and the piston 12b. One end of the connection pipe 14 is connected to the compression chamber 12e.

  The piston 12b is vibrated in the axial direction by driving the linear actuator 12c. Thereby, the volume of the compression chamber 12e is increased or decreased in vibration, and pressure oscillation of the refrigerant gas in the compression chamber 12e is generated. As an example, the average pressure of the pressure oscillation is, for example, in the order of megapascals, for example in the range of about 1-3 MPa, the pressure amplitude is in the range of, for example, about 0.5-1 MPa, and the frequency is in the range of, for example, about 50-60 Hz. May be.

  The connecting pipe 14 fluidly connects the pressure vibration source 12 to the expander 16. That is, the connection pipe 14 connects the pressure vibration source 12 and the expander 16 so that the refrigerant gas can flow between the pressure vibration source 12 and the expander 16 in both directions. Therefore, the pressure vibration of the refrigerant gas generated by the pressure vibration source 12 is transmitted to the expander 16 via the connection pipe 14, thereby inducing the pressure vibration in the expander 16. The connecting pipe 14 may be a flexible pipe or a rigid pipe.

  The regenerator 18 includes a regenerator tube 26 extending in the axial direction A and a regenerator tube fastening structure 28. The cold storage pipe 26 includes a cold storage material 30 and a cold storage material container 32 that is filled with the cold storage material 30 and extends in the axial direction A. Although details will be described later, the regenerator tube fastening structure 28 is configured to tighten the regenerator tube 26 from the outside in the radial direction so as to reduce the gap in the radial direction B between the regenerator material 30 and the regenerator material container 32. Yes.

  The cold storage material 30 is, for example, a plurality of meshes (for example, a highly heat conductive metal material such as copper, or other metal mesh) or a laminate of mesh members. Alternatively, the cold storage material 30 may be a sintered body or a porous body. The cold storage material 30 may be a granular cold storage material. As an example, the cold storage material container 32 has a cylindrical shape extending in the axial direction A. Alternatively, the regenerator container 32 may have a donut shape or a cylindrical shape. The cool storage material container 32 may be made of, for example, stainless steel or other appropriate metal material.

  The regenerator 18 has a regenerator high temperature end 18a and a regenerator low temperature end 18b. The regenerator tube 26 and the regenerator material container 32 extend in the axial direction A from the regenerator high temperature end 18a to the regenerator low temperature end 18b. The regenerator high temperature end 18 a is connected to the other end of the connection pipe 14, and is connected to the compression chamber 12 e of the pressure vibration source 12 through the connection pipe 14. The regenerator high temperature end 18a may be provided with a heat exchanger called an aftercooler or other heat radiating member.

  The pulse tube 22 is a tubular member having, for example, a cylinder or other suitable shape, and has an internal space in which a refrigerant gas can be accommodated. The regenerator 18 and the phase control unit 24 are fluidly connected via a pulse tube 22. In the illustrated cryogenic refrigerator 10, a refrigerant gas flow path that bypasses the regenerator 18 and the pulse tube 22 is not provided. Therefore, all the gas flow between the pressure vibration source 12 and the phase control unit 24 passes through the regenerator 18 and the pulse tube 22.

  The pulse tube 22 has a pulse tube hot end 22a and a pulse tube cold end 22b. The pulse tube low temperature end 22b is connected to the regenerator low temperature end 18b. The pulse tube cold end 22b and the regenerator cold end 18b communicate with each other, whereby the pulse tube 22 and the regenerator 18 are fluidly connected. The pulse tube cold end 22b is structurally rigidly coupled to the regenerator cold end 18b.

  A cooling stage 20 is installed at a joint between the pulse tube cold end 22b and the regenerator cold end 18b so as to surround the joint. The cooling stage 20 is made of a highly heat conductive metal material such as copper. The cooling stage 20 is thermally coupled to the pulse tube cold end 22b and the regenerator cold end 18b. As described above, the cooling stage 20 can be provided with a desired object to be cooled by the cryogenic refrigerator 10.

  A phase controller 24 is provided at the high temperature end 22a of the pulse tube. The phase controller 24 includes an inertance tube 34 connected to the pulse tube high temperature end 22a, and a buffer tank 36 fluidly connected to the pulse tube high temperature end 22a via the inertance tube 34. The inertance pipe 34 may be a flexible pipe or a rigid pipe. The inertance tube 34 is, for example, significantly longer than the axial length of the regenerator 18 and / or pulse tube 22 (e.g., can be at least about 1 m, or several m), so it can be coiled, serpentine or other curved shape It may be molded.

  FIG. 2 is a schematic view showing a DD cross section of the expander 16 of the cryogenic refrigerator 10 shown in FIG. FIG. 2 shows a regenerator tube 26 and a regenerator tube fastening structure 28. The cold storage pipe 26 includes the cold storage material 30 and the cold storage material container 32 as described above.

  As shown in FIGS. 1 and 2, the regenerator tube fastening structure 28 includes a ring-shaped clamp member 38 that extends in the circumferential direction C along the outer surface of the regenerator container 32. The clamp member 38 includes a C-shaped ring member 38a and a fastening member 38b such as a bolt for fastening both ends of the ring member 38a.

  By tightening the fastening member 38b, both ends of the ring member 38a approach each other, and as a result, the diameter of the clamp member 38 is reduced. Thus, the clamp member 38 can tighten the regenerator tube 26 from the outside in the radial direction and reduce the radial gap between the regenerator material 30 and the regenerator material container 32. On the contrary, by loosening the fastening member 38b, the diameter of the clamp member 38 is widened, and the clamp member 38 can be removed from the cold storage tube 26.

  As an example, the clamp member 38 is attached to the regenerator tube 26 at an intermediate position between the regenerator hot end 18a and the regenerator cold end 18b in the axial direction A. Although only one clamp member 38 is provided, the present invention is not limited to this. The plurality of clamp members 38 may be attached to the regenerator tube 26 at different positions in the axial direction A.

  FIG. 3 is a schematic diagram showing a regenerator 40 of a cryogenic refrigerator according to a comparative example. The regenerator 40 includes a regenerator 40a and a container 40b. Unlike the above-described embodiment, the regenerator 40 does not have a regenerator tube fastening structure. Therefore, a gap 42 in the radial direction B can exist between the cold storage material 40a and the container 40b. There are various causes for the gap 42 to be generated, but as an example, it is caused by expansion deformation of the container 40b due to the refrigerant gas filling pressure (shown by a broken line in FIG. 3). Typically, the charging pressure of the refrigerant gas is sufficiently higher than the ambient environment pressure (for example, atmospheric pressure), so that the container 40b can expand outward in the radial direction B due to the pressure difference.

  Further, in order to easily insert or fill the cool storage material 40a into the container 40b in the manufacturing process, the fitting between the cool storage material 40a and the container 40b is appropriately designed, and the outer side of the cool storage material 40a is more than the inner diameter of the container 40b. The diameter is slightly smaller. This can also cause the gap 42.

  Furthermore, thermal contraction of the regenerator material 40a due to cooling can also cause the gap 42. Due to cooling from the ambient environment temperature (for example, room temperature) of the cryogenic refrigerator 10 to the cooling temperature (for example, the temperature of the outer surface of the container 40b during operation of the cryogenic refrigerator 10), both the cold storage material 40a and the container 40b are thermally contracted. Yes. If the thermal contraction rate of the cold storage material 40a is larger than the thermal contraction rate of the container 40b, the gap 42 expands with cooling.

  When the gap 42 exists between the cool storage material 40 a and the container 40 b in the regenerator 40, as indicated by an arrow 44, a bypass flow that bypasses the cool storage material 40 a through the gap 42 inside the regenerator 40 is likely to occur. While the cold storage material 40a has a certain amount of flow path resistance, the gap 42 is a space having nothing, and thus the flow path resistance is significantly smaller than the cold storage material 40a. Even if the size of the gap 42 is quite small, in some cases, most of the refrigerant gas flowing through the regenerator 40 may pass through the gap 42 and the refrigerant gas passing through the regenerator material 40a may be greatly reduced. The efficiency of heat exchange between the cold storage material 40a and the refrigerant gas is reduced, and as a result, the refrigeration performance of the cryogenic refrigerator is also reduced. In particular, in a Stirling type pulse tube refrigerator, the flow rate of the refrigerant gas is relatively large, so that such a bypass flow is likely to occur, and the refrigeration performance is likely to be affected.

  However, according to the cryogenic refrigerator 10 according to the present embodiment, since the regenerator tube fastening structure 28, specifically, the clamp member 38 is provided, the regenerator tube 26 is tightened from the outside in the radial direction, and the regenerator material 30 is provided. Can be reduced, and preferably the gap can be eliminated. Therefore, heat exchange between the refrigerant gas and the regenerator 30 is performed satisfactorily in the regenerator 18, and a decrease in the refrigerating performance of the cryogenic refrigerator 10 is suppressed.

  In addition, since the cold storage tube tightening structure 28 can tighten the cold storage tube 26 in a state where the cold storage material 30 is stored in the cold storage material container 32, the gap between the cold storage material container 32 and the cold storage material 30 can be minimized. It is allowed to design an appropriate fit between the cool storage material container 32 and the cool storage material 30. Therefore, manufacture of the cryogenic refrigerator 10 becomes easy.

  Furthermore, since the gap between the cool storage material container 32 and the cool storage material 30 can be minimized by tightening the cool storage tube 26, the wall thickness (that is, the radial dimension) of the cool storage material container 32 can be reduced. Thereby, the heat conduction through the cool storage material container 32 can be reduced. That is, it is possible to reduce the amount of heat entering the cryogenic refrigerator 10 from the regenerator high temperature end 18a through the regenerator container 32 to the regenerator low temperature end 18b. This also helps to suppress a decrease in the refrigeration performance of the cryogenic refrigerator 10.

  The regenerative tube fastening structure 28 is not limited to the above-described example, and can take various structures. Some examples are described below.

  FIG. 4 is a schematic diagram illustrating another example of the regenerator tube fastening structure 28 that can be applied to the cryogenic refrigerator 10 according to an embodiment. The cold storage pipe fastening structure 28 includes a wire member 46 wound around the outer surface of the cold storage material container 32, and a first attachment 48a and a second attachment 48b for attaching the wire member 46 to the cold storage material container 32. .

  The wire member 46 has one end attached to the first attachment 48a and the other end attached to the second attachment 48b, and extends from the first attachment 48a to the second attachment 48b. In FIG. 4, the regenerator tube fastening structure 28 has two wire members 46, but the number of wire members 46 is not limited to this and is arbitrary. The wire member 46, the first fixture 48a, and the second fixture 48b are formed of any appropriate material such as metal.

  The first fixture 48a has an annular shape so that the cold storage material container 32 is inserted through the central opening thereof. A plurality of wire members 46 are attached to the first attachment 48a at equal angular intervals. Similarly, the second fixture 48b has an annular shape so that the cold storage material container 32 is inserted through the central opening thereof, and a plurality of wire members 46 are attached to the second fixture 48b at equal angular intervals. ing.

  The first fixture 48a is fixed to the cold storage material container 32 using a fastening member such as a bolt at a first position in the axial direction A (for example, the cold storage cold end 18b or the vicinity thereof). The second attachment 48b is attached to the regenerator container 32 so as to be rotatable in the circumferential direction C at a second position in the axial direction A (for example, the regenerator high temperature end 18a or the vicinity thereof). For example, a screw surface may be formed on the outer surface of the cool storage material container 32, and the second attachment 48 b may be rotatable with respect to the cool storage material container 32 on this screw surface. In this way, a rotary fastening mechanism for the wire member 46 is configured.

  In this way, the wire member 46 is arranged from the first fixture 48a to the second fixture 48b along the outer surface of the cool storage material container 32 so as to be wound around the cool storage material container 32 by the rotation of the second fixture 48b. It is installed. The wire member 46 is spirally wound around the cold storage material container 32. When the rotation operation of the second fixture 48b is performed, the wire member 46 is pulled (or loosened), and the fastening force acting on the cold storage material container 32 from the wire member 46 changes.

  Also in this case, the regenerator tube fastening structure 28 can tighten the regenerator tube 26 from the outside in the radial direction to reduce the radial gap between the cool storage material 30 and the cool storage material container 32, and preferably eliminate the gap. . Therefore, heat exchange between the refrigerant gas and the cold storage material 30 is performed satisfactorily, and a decrease in the refrigeration performance of the cryogenic refrigerator is suppressed. An appropriate fit can be designed between the cold storage material container 32 and the cold storage material 30. The wall thickness (namely, radial direction dimension) of the cool storage material container 32 can be made thin.

  FIG. 5 is a schematic diagram illustrating another example of the regenerator tube fastening structure 28 that can be applied to the cryogenic refrigerator 10 according to an embodiment. The regenerator tube tightening structure 28 includes a tightening ring 50 that extends in the circumferential direction C along the outer surface of the regenerator container 32. The tightening ring 50 is fixed to the outer surface of the cool storage material container 32 and is thermally coupled to the cool storage material container 32. The ring member 38a of the clamp member 38 in the above-described embodiment has a C-shape having a notch, but the fastening ring 50 shown in FIG. 5 has an O-shape that is continuous over the entire circumference.

  The cool storage material container 32 is made of a first material, for example, a first metal material, and the fastening ring 50 is made of a second material different from the first material. The first material may be stainless steel, for example. The second material may be a second metal material, a resin material, or other material. The second material may be, for example, copper or a phenol resin such as Bakelite (registered trademark).

  However, the second material is a material that has a higher thermal shrinkage rate than the first material. More specifically, the thermal contraction rate (%) of the second material is larger than the thermal contraction rate (%) of the first material when cooled from the first reference temperature to the second reference temperature. The first reference temperature may be, for example, room temperature or any other temperature. The second reference temperature is a temperature lower than the first reference temperature, and may be, for example, a cooling temperature at an axial position on the cool storage material container 32 where the fastening ring 50 is installed.

  As an example, the tightening ring 50 is attached to the regenerator tube 26 at an intermediate position between the regenerator high temperature end 18a and the regenerator low temperature end 18b in the axial direction A. Although only one clamping ring 50 is provided, the present invention is not limited to this. A plurality of fastening rings 50 may be attached to the regenerator tube 26 at different positions in the axial direction A.

  In this way, as the regenerator container 32 is cooled by the operation of the cryogenic refrigerator, the diameter of the tightening ring 50 becomes smaller than that of the regenerator container 32, and the tightening ring 50 connects the regenerator pipe 26. Can be tightened. Conversely, when the temperature of the cold storage material container 32 is raised, the diameter of the tightening ring 50 increases and the tightening is released.

  Also in this case, the regenerator tube fastening structure 28 can tighten the regenerator tube 26 from the outside in the radial direction to reduce the radial gap between the cool storage material 30 and the cool storage material container 32, and preferably eliminate the gap. . Therefore, heat exchange between the refrigerant gas and the cold storage material 30 is performed satisfactorily, and a decrease in the refrigeration performance of the cryogenic refrigerator is suppressed. An appropriate fit can be designed between the cold storage material container 32 and the cold storage material 30. The wall thickness (namely, radial direction dimension) of the cool storage material container 32 can be made thin.

  Further, the regenerative tube tightening structure 28 having the tightening ring 50 is a rigid structure, and thus has high reliability.

  In the above, this invention was demonstrated based on the Example. It will be understood by those skilled in the art that the present invention is not limited to the above-described embodiment, and various design changes are possible, various modifications are possible, and such modifications are within the scope of the present invention. By the way. Various features described in connection with one embodiment are also applicable to other embodiments. New embodiments resulting from the combination have the effects of the combined embodiments.

  In the above-described embodiment, the regenerator 18 has a solid shape such as a cylinder, but is not limited thereto. As shown in FIG. 6, the regenerator 18 has a hollow shape such as a donut shape. May be. The cold storage tube 26 may include a cold storage material 30 and a cold storage material container 32 that is filled with the cold storage material 30 and extends in the axial direction. The regenerator tube 26 has a hollow shape. The regenerator tube tightening structure 28 may be configured to tighten the regenerator tube 26 from the radially outer side so as to reduce the radial gap between the regenerator material 30 and the regenerator material container 32. Such a hollow regenerator 18 may be applied to a Stirling refrigerator, for example.

  A plurality of types of regenerator tube fastening structures 28 may be used in combination with a certain regenerator 18. In some embodiments, the regenerator tube clamping structure 28 may include at least two of a clamp member 38, a wire member 46, and a clamping ring 50.

  The regenerator tube fastening structure 28 and the regenerator 18 having the regenerator tube tightening structure 28 are not only Stirling type pulse tube refrigerators, but also other pulse tube refrigerators such as GM type pulse tube refrigerators, or other cryogenic refrigerators such as Stirling refrigerators. It can also be applied to.

  10 cryogenic refrigerator, 18 regenerator, 26 regenerator tube, 28 regenerator tube tightening structure, 30 regenerator material, 32 regenerator material container, 38 clamp member, 46 wire member, 50 tightening ring, A axial direction, B radial direction , C Circumferential direction.

Claims (5)

A regenerator for a cryogenic refrigerator,
A regenerator tube comprising a regenerator material, and a regenerator container filled with the regenerator material and extending in the axial direction;
A regenerator having a regenerator tube tightening structure for tightening the regenerator tube from the radially outer side so as to reduce a radial gap between the regenerator material and the regenerator material container.   The regenerator according to claim 1, wherein the regenerator tube tightening structure includes a ring-shaped clamp member extending in a circumferential direction along an outer surface of the regenerator container.   The regenerator according to claim 1 or 2, wherein the regenerator tube tightening structure includes a wire member wound around an outer surface of the regenerator material container. The cold storage material container is formed of a first material,
The cold storage tube tightening structure includes a tightening ring that extends in the circumferential direction along the outer surface of the cold storage material container and is formed of a second material, and the second material has a heat shrinkage rate due to cooling of the second material. The regenerator according to any one of claims 1 to 3, wherein the regenerator is larger than the first material.   A cryogenic refrigerator comprising the regenerator according to any one of claims 1 to 4.

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