JP5541795B2 - Regenerator type refrigerator - Google Patents

Description

  The present invention relates to a regenerator type refrigerator having a regenerator containing a regenerator material using a refrigerant gas such as helium gas.

  For example, in order to obtain an extremely low temperature of about 4K, a regenerator type refrigerator having a regenerator that stores a regenerator material using a refrigerant gas such as helium gas is used. In addition, as a regenerator type refrigerator, for example, a Gifford-McMahon (GM) refrigerator is used.

  The GM refrigerator generates cold by supplying a refrigerant gas made of, for example, helium gas from a compressor to an expansion space formed in the cylinder, and expanding the supplied refrigerant gas in the expansion space.

  Each stage of the GM refrigerator has a cylinder and a displacer provided in the cylinder. The displacer is provided in the cylinder so as to be capable of reciprocating along the cylinder, and forms an expansion space between one end of the displacer and the cylinder. In addition, a refrigerant gas flow path for supplying and discharging refrigerant gas to and from the expansion space is formed inside the displacer. In addition, the refrigerant gas passage formed inside the displacer contains a regenerator material for accumulating cold heat in contact with the refrigerant gas.

  The displacer has an outer diameter that is slightly smaller than the inner diameter of the cylinder in order to expand or contract the expansion space hermetically by reciprocating along the cylinder. A seal is provided between the outer peripheral surface of the displacer and the inner peripheral surface of the cylinder to keep the gap between the displacer and the cylinder airtight. Conventionally, seal rings, clearance seals, labyrinth seals, spiral groove seals (see, for example, Patent Document 1) and the like have been used as such seals.

  On the other hand, the GM refrigerator has a drive shaft that reciprocates the displacer. The drive shaft is connected to, for example, a motor that is driven to rotate, and converts the rotational driving force into a reciprocating driving force and transmits it to the displacer. The displacer is connected to the drive shaft by, for example, a universal joint (for example, see Patent Document 2).

Japanese Patent No. 2659684 JP 2004-239563 A

  However, the above-described regenerator refrigerators such as the GM refrigerator have the following problems.

  Other seals (clearance seal, labyrinth seal, spiral groove seal, etc.) excluding the seal ring are originally non-contact seals when the cylinder is arranged vertically. However, when the cylinder is arranged horizontally, or when the cylinder is inclined with respect to the vertical direction, a part of the outer peripheral surface of the displacer may come into contact with the inner peripheral surface of the cylinder.

  In particular, when the cylinder is disposed horizontally, a part of the outer peripheral surface of the displacer comes into contact with the inner peripheral surface of the cylinder due to the weight of the displacer. When the GM refrigerator is operated for a long time in a state where a part of the outer peripheral surface of the displacer is in contact with the inner peripheral surface of the cylinder, only the contact portion is worn, and thus the displacer wears unevenly. When the displacer wears unevenly, the gap between the cylinder and the displacer increases, the amount of refrigerant gas leaked from the expansion space increases, and the refrigeration capacity of the GM refrigerator may decrease. Or when the partial wear of the displacer further proceeds, there is a problem that the life of the GM refrigerator is shortened.

  As disclosed in Patent Document 2, there is a type in which a displacer is connected to a drive shaft via a universal joint. However, even when connected via a universal joint, a part of the outer peripheral surface of the displacer remains in contact with the inner peripheral surface of the cylinder, and uneven wear of the displacer cannot be prevented.

  Also, when the cylinder is arranged vertically, due to the dimensional tolerance of the outer diameter of the displacer or the dimensional tolerance of the inner diameter of the cylinder, a part of the outer peripheral surface of the displacer contacts the inner peripheral surface of the cylinder, and the displacer There may be uneven wear. Therefore, the above-described problem is a common problem not only when the cylinder is inclined with respect to the vertical direction but also when the cylinder is vertically disposed.

  This invention is made | formed in view of said point, and provides the regenerator-type refrigerator which can prevent the uneven wear of the outer peripheral surface of a displacer.

  In order to solve the above problems, the present invention is characterized by the following measures.

  The present invention is provided in a cylinder and in the cylinder so as to be capable of reciprocating along the cylinder, and forms an expansion space at one end of the cylinder, and supplies and discharges refrigerant gas into the expansion space. A cylindrical displacer in which a refrigerant gas flow path is formed, a drive shaft that reciprocally drives the displacer, and the refrigerant gas flow path accommodated in the refrigerant gas flow path. A regenerator material for storing cold heat generated by expanding the refrigerant gas supplied to the expansion space when reciprocating along the line, and the displacer has a central axis of the displacer on the drive shaft. It is a regenerator type refrigerator that is rotatably connected as a center.

  Further, the present invention is the above-described regenerator-type refrigerator, wherein the displacer is connected to the drive shaft so as to be rotatable about the center axis of the displacer, and the center axis of the displacer with respect to the drive shaft It is connected to allow tilt.

  Further, according to the present invention, in the above-described regenerator type refrigerator, the displacer is connected to the drive shaft via a spherical bearing.

  Further, in the present invention, in the above-described regenerator type refrigerator, a spiral groove is formed on the outer peripheral surface of the displacer or the inner peripheral surface of the cylinder.

  According to the present invention, in the regenerator type refrigerator, uneven wear of the outer peripheral surface of the displacer can be prevented.

It is a schematic sectional drawing which shows the structure of the GM refrigerator which concerns on 1st Embodiment. It is a schematic sectional drawing which shows the structure of the 1st step displacer with the 1st step cylinder in the GM refrigerator which concerns on 1st Embodiment. It is a schematic sectional drawing which shows the structure of the 2nd stage displacer in the GM refrigerator which concerns on 1st Embodiment with a 2nd stage cylinder. It is a schematic sectional drawing which shows another example of a structure of a 2nd stage displacer with a 2nd stage cylinder. It is a figure showing typically about the example by which the 2nd stage cylinder of the GM refrigerator concerning a 1st embodiment is arranged horizontally. It is a figure showing typically about the example where the 2nd stage cylinder of the GM refrigerator concerning a comparative example is arranged horizontally. It is a schematic sectional drawing which shows the structure of the 2nd step displacer with the 2nd step cylinder in the GM refrigerator which concerns on the 1st modification of 1st Embodiment. It is a schematic sectional drawing which shows the structure of the 2nd stage displacer in the GM refrigerator which concerns on the 2nd modification of 1st Embodiment with a 2nd stage cylinder. It is a schematic sectional drawing which shows the structure of the 1st stage displacer with the 1st stage cylinder in the GM refrigerator which concerns on 2nd Embodiment.

Next, a mode for carrying out the present invention will be described with reference to the drawings.
(First embodiment)
A GM refrigerator according to the first embodiment will be described with reference to FIG. This GM refrigerator is an example in which the regenerator type refrigerator according to the present invention is applied to a GM refrigerator, and has a two-stage configuration suitable for obtaining a cryogenic temperature of about several K to 20K.

  FIG. 1 is a schematic cross-sectional view showing the configuration of the GM refrigerator according to the present embodiment.

  The GM refrigerator includes a compressor 10, a first stage cylinder 11, a second stage cylinder 12, a first stage displacer 13, a second stage displacer 14, a crank mechanism 15, a refrigerant gas passage 16, and a cold storage material 17. , 18, heat stations 19 and 20, expansion spaces 21 and 22, and hollow spaces (refrigerant gas flow paths) 23 and 24.

The compressor 10 compresses helium gas (refrigerant gas) to about 20 Kgf / cm ² to generate high-pressure helium gas. The generated high-pressure helium gas is supplied into the first stage cylinder 11 via the intake valve V1 and the refrigerant gas flow path 16. Further, the low-pressure helium gas discharged from the first stage cylinder 11 is recovered by the compressor 10 via the refrigerant gas passage 16 and the exhaust valve V2.

  A second stage cylinder 12 is coupled to the first stage cylinder 11. A first stage displacer 13 and a second stage displacer 14 connected to each other are accommodated in the first stage cylinder 11 and the second stage cylinder 12, respectively.

  From the first stage cylinder 11, the drive shaft Sh extends upward and is coupled to a crank mechanism 15 coupled to the drive motor M.

  The first stage displacer 13 is provided in the first stage cylinder 11 so as to be capable of reciprocating along the first stage cylinder 11. The first stage displacer 13 forms an expansion space 21 at one end of the first stage cylinder 11. The first stage displacer 13 has a cylindrical shape with an outer diameter slightly smaller than the inner diameter of the first stage cylinder 11.

  Further, a hollow space (refrigerant gas flow path) 23 for supplying and discharging refrigerant gas to and from the expansion space 21 is formed inside the first stage displacer 13. When the first stage displacer 13 reciprocates along the first stage cylinder 11, the first stage displacer 13 generates cold heat by expanding the refrigerant gas supplied to the expansion space 21.

  A cold storage material 17 is accommodated in the hollow space 23. When discharging the refrigerant gas from the expansion space 21, the cold storage material 17 contacts the discharged refrigerant gas and stores cold heat. That is, the regenerator 17 generates the cold generated by expanding the refrigerant gas supplied to the expansion space 21 when the first stage displacer 13 is reciprocated along the first stage cylinder 11 by the drive shaft Sh. Cold storage.

  The second stage displacer 14 is provided in the second stage cylinder 12 so as to be capable of reciprocating along the second stage cylinder 12. The second stage displacer 14 forms an expansion space 22 at one end of the second stage cylinder 12. The second stage displacer 14 has a cylindrical shape with an outer diameter slightly smaller than the inner diameter of the second stage cylinder 12.

  In addition, a hollow space (refrigerant gas flow path) 24 for supplying and discharging refrigerant gas to and from the expansion space 22 is formed inside the second stage displacer 14. The second stage displacer 14 generates cold by expanding the refrigerant gas supplied to the expansion space 22 when reciprocating along the second stage cylinder 12.

  A cold storage material 18 is accommodated in the hollow space 24. When discharging the refrigerant gas from the expansion space 22, the cold storage material 18 contacts the discharged refrigerant gas and stores cold heat. That is, the regenerator 18 generates the cold generated by expanding the refrigerant gas supplied to the expansion space 22 when the second stage displacer 14 is reciprocated along the second stage cylinder 12 by the drive shaft Sh. Cold storage.

  The first stage heat station 19 is thermally coupled so as to surround the lower end (low temperature end) of the first stage cylinder 11, and so as to surround the lower end (low temperature end) of the second stage cylinder 12. The second stage heat station 20 is thermally coupled.

  The first stage cylinder 11 and the second stage cylinder 12 are preferably formed of, for example, a stainless steel (for example, SUS304). As a result, the first-stage cylinder 11 and the second-stage cylinder 12 can have high strength, low thermal conductivity, and high helium gas shielding ability.

  The first stage displacer 13 and the second stage displacer 14 are preferably formed of, for example, cloth-containing phenol (bakelite) or the like. Accordingly, the first stage displacer 13 and the second stage displacer 14 can be reduced in weight, wear resistance and strength can be improved, and the amount of heat entering from the high temperature side to the low temperature side can be reduced.

  The first-stage regenerator material 17 is preferably composed of, for example, a wire mesh, and the second-stage regenerator material 18 is preferably composed of, for example, a lead ball or a magnetic regenerator material. Thereby, a sufficiently high heat capacity can be secured in the low temperature region.

  In the GM refrigerator configured as described above, cold heat is generated as follows.

  High-pressure helium gas, which is refrigerant gas, supplied from the compressor 10 via the intake valve V <b> 1 is supplied into the first-stage cylinder 11 via the refrigerant gas flow path 16. Then, the gas is supplied to the first-stage expansion space 21 through the opening (refrigerant gas flow path) 23a, the hollow space (refrigerant gas flow path) 23 in which the regenerator material 17 is accommodated, and the opening (refrigerant gas flow path) 23b. Is done.

  The high-pressure helium gas supplied to the first-stage expansion space 21 further includes an opening (refrigerant gas flow path) 24a, a hollow space (refrigerant gas flow path) 24 in which the regenerator 18 is accommodated, and an opening (refrigerant gas flow path). ) Is supplied to the second stage expansion space 22 through 24b.

  Note that the refrigerant gas flow paths 23a, 23b, 24a, and 24b are functionally described to explain the flow of the refrigerant gas, and are different from the actual structure described with reference to FIG.

  When the intake valve V1 is closed and the exhaust valve V2 is opened, the high-pressure helium gas in the second-stage cylinder 12 and the first-stage cylinder 11 follows the path opposite to that in the intake air, and the refrigerant gas flow path. 16. Recovered to the compressor 10 via the exhaust valve V2.

  During the operation of the GM refrigerator, the rotational driving force of the driving motor M is converted into the reciprocating driving force of the driving shaft Sh by the crank mechanism 15. The first stage displacer 13 and the second stage displacer 14 are moved up and down by the drive shaft Sh as shown by arrows in FIG. 1 (to the first stage cylinder 11 and the second stage cylinder 12 respectively). Along).

When the first stage displacer 13 and the second stage displacer 14 are driven to the drive shaft Sh side ( upward in FIG. 1) by the drive shaft Sh, the intake valve V1 is opened and the exhaust valve V2 is closed. Then, high-pressure helium gas is supplied to the expansion space 21 in the first stage cylinder 11 and the expansion space 22 in the second stage cylinder 12 (supply process).

Further, when the first stage displacer 13 and the second stage displacer 14 are driven by the drive shaft Sh to the side opposite to the drive shaft Sh ( downward in FIG. 1), the intake valve V1 is closed and the exhaust valve V2 is closed. open. Then, the expansion space 21 in the first stage cylinder 11 and the expansion space 22 in the second stage cylinder 12 become low pressure, and helium gas is discharged from the expansion space 21 and the expansion space 22 to the compressor 10. Collected (discharge process).

  At this time, cold energy is generated by the expansion of the helium gas in the expansion spaces 21 and 22. When the cooled helium gas that generates cold and is discharged from the expansion spaces 21 and 22 contacts the cold storage materials 17 and 18 to exchange heat, the cold storage materials 17 and 18 are cooled. That is, the generated cold energy is stored in the cold storage materials 17 and 18.

  The high-pressure helium gas supplied in the next supply process is cooled by being supplied through the cold storage materials 17 and 18. As the cooled helium gas expands in the expansion spaces 21 and 22, the cooling further proceeds.

  By repeating the supply process and the discharge process as described above, the expansion space 21 in the first stage cylinder 11 is cooled to a temperature of about 40K to 70K, for example, and the expansion in the second stage cylinder 12 is performed. The space 22 is cooled to a temperature of about several K to 20K, for example.

  Next, a detailed configuration of the first stage displacer 13 will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing the configuration of the first stage displacer 13 together with the first stage cylinder 11 in the GM refrigerator according to the present embodiment. In addition, illustration of the heat station 19 is abbreviate | omitted in FIG.

  The first stage displacer 13 has a cylindrical member 30.

  The cylindrical member 30 has a cylindrical shape with an upper lid, and its lower end is open. A flange 31 having a diameter slightly smaller than the outer diameter of the tubular member 30 is attached to the upper surface of the upper cover of the tubular member 30. An opening 32 (23a shown in FIG. 1) is provided in the upper cover of the flange 31 and the cylindrical member 30. A high temperature end of the hollow space (refrigerant gas flow path) 23 communicates with the opening 32. A drive shaft Sh for vertically driving the cylindrical member 30 is attached to the upper surface of the flange 31 as indicated by an arrow in FIG.

  A wire mesh (not shown) is disposed in the cylindrical member 30 so as to be in close contact with the upper surface. Under the wire mesh, a regenerator material 17 such as a copper wire mesh is filled. Another wire mesh (not shown) is disposed under the cold storage material 17.

  Further, a lid member 33 is inserted into the lower open end of the tubular member 30 and bonded to the tubular member 30. The lid member 33 is a blind lid and hermetically closes the opening at the lower end of the cylindrical member 30. Further, a connection mechanism 50 for connecting to the second stage displacer 14 is attached to the lower surface of the lid member 33.

  An opening 34 (23b shown in FIG. 1) is provided on the outer peripheral surface of the cylindrical member 30 at a height at which the lower wire mesh of the regenerator 17 is disposed. The opening 34 communicates with the low temperature end of the hollow space (refrigerant gas flow path) 23.

  It is preferable that the cylindrical member 30 and the lid member 33 are made of cloth-containing phenol, for example. Thereby, while reducing the weight about the cylindrical member 30 and the cover member 33, abrasion resistance and intensity | strength can be improved and the amount of invasion heat | fever from the high temperature side to the low temperature side can be reduced.

  When the inner diameter of the first stage cylinder 11 is 82 mm, for example, the outer diameter of the cylindrical member 30 can be 82 mm and the inner diameter can be 72 mm, for example. Moreover, the outer diameter of the lower part than the opening 34 of the cylindrical member 30 and the outer diameter of the flange 31 can be 81.5 mm, for example. Moreover, the axial length of the cylindrical member 30 can be set to 150 mm, for example, and the thickness of the flange 31 can be set to 10 mm, for example.

  A gap D <b> 11 is formed between the outer peripheral surface of the cylindrical member 30 and the inner peripheral surface of the first stage cylinder 11. In order to stably drive the first stage displacer 13 back and forth, the gap D11 is preferably 0.01 mm or more. In order to prevent the refrigerant gas from flowing through the gap D11, the gap D11 is preferably 0.03 mm or less.

  One spiral groove 35 may be formed on the outer peripheral surface of the cylindrical member 30 from the upper end (high temperature end) to the height at which the opening 34 is formed. As the shape of the spiral groove 35, for example, the width is about 2 mm, the depth is about 0.6 mm, and the pitch is about 4 mm. By forming the spiral groove 35 in this way, it is possible to prevent the refrigerant gas from leaking through the gap D11 between the first stage displacer 13 and the first stage cylinder 11.

  The outer diameter of the portion below the opening 34 of the cylindrical member 30 may be slightly smaller than the outer diameter of the portion above the opening 34. At this time, a gap D <b> 12 is formed between the inner peripheral surface of the first stage cylinder 11 and the outer peripheral surface of the cylindrical member 30 in a portion below the opening 34. The gap D12 forms a refrigerant gas flow path that connects the inside of the cylindrical member 30 and the expansion space 21.

  Next, a detailed configuration of the second stage displacer 14 will be described with reference to FIG.

  In the present embodiment, the second stage displacer 14 is coupled to the drive shaft Sh so as to be rotatable about the central axis of the second stage displacer 14.

  The second stage displacer 14 is connected to the drive shaft Sh via the first stage displacer 13. Therefore, the second stage displacer 14 may be connected to the first stage displacer 13 so as to be rotatable about the central axis of the second stage displacer 14. Also in this case, the second stage displacer 14 is connected to the drive shaft Sh so as to be rotatable about the central axis of the second stage displacer 14.

  FIG. 3 is a schematic cross-sectional view showing the configuration of the second stage displacer 14 together with the second stage cylinder 12 in the GM refrigerator according to the present embodiment. In addition, illustration of the heat station 20 is abbreviate | omitted in FIG.

  The second stage displacer 14 includes a tubular member 40. The second stage displacer 14 is connected to the first stage displacer 13 (that is, the drive shaft Sh) via the connection mechanism 50.

  The cylindrical member 40 has a cylindrical shape whose upper and lower ends are open. A lid member 41 is inserted and bonded to the lower end of the cylindrical member 40. A wire mesh 42 is disposed on the lid member 41, and a felt plug 43 is disposed thereon.

  The tubular member 40 and the lid member 41 are preferably formed of cloth-containing phenol, for example. Thereby, while reducing weight about the cylindrical member 40 and the cover member 41, abrasion resistance and intensity | strength can be improved and the amount of invasion heat | fever from the high temperature side to the low temperature side can be reduced.

  As described above, the felt plug 43 is filled with the regenerator material 18 formed of, for example, a lead ball. A felt plug 44 is disposed on the cold storage material 18, and a punching metal 45 is disposed on the felt plug 44.

  At the upper end (high temperature end) of the cylindrical member 40, a connection mechanism 50 described later for connecting to the first stage displacer 13 is attached. An opening 24 a is provided around the coupling mechanism 50 at the upper end (high temperature end) of the tubular member 40. The opening 24 a communicates with the high temperature end of the hollow space (refrigerant gas flow path) 24.

  On the outer peripheral surface of the cylindrical member 40, an opening 46 (24b shown in FIG. 1) is provided at the height of the wire mesh 42. The opening 46 communicates with the low temperature end of the hollow space (refrigerant gas flow path) 24.

  When the inner diameter of the second stage cylinder 12 is set to 35 mm, for example, the outer diameter of the cylindrical member 40 can be set to 35 mm and the inner diameter can be set to 30 mm, for example. Moreover, the axial length of the cylindrical member 40 can be set to 200 mm, for example.

  A gap D <b> 21 is formed between the outer peripheral surface of the cylindrical member 40 and the inner peripheral surface of the second stage cylinder 12. In order to stably drive the second stage displacer 14 back and forth, the gap D21 is preferably 0.01 mm or more. In order to prevent the refrigerant gas from flowing in the axial direction through the gap D21, the gap D21 is preferably 0.03 mm or less.

  It is preferable that one spiral groove 47 connecting the position of the opening 46 and the upper end is formed on the outer peripheral surface of the portion above the opening 46 of the cylindrical member 40. As the shape of the spiral groove 47, for example, the width is about 2 mm, the depth is about 0.6 mm, and the pitch is about 4 mm.

  By forming the spiral groove 47 in this way, it is possible to prevent the refrigerant gas from leaking through the gap D21 between the second stage displacer 14 and the second stage cylinder 12. As a result, since it is not necessary to accommodate the seal ring in the gap between the second stage displacer 14 and the second stage cylinder 12, the thickness of the side wall of the tubular member 40 can be reduced. By reducing the thickness of the side wall of the tubular member 40, the volume of the hollow space 24 in the second-stage displacer 14 can be increased, so that it is possible to increase the amount of cool storage material to be accommodated and to increase the refrigeration capacity of the GM refrigerator. Can be increased. Further, since the seal ring is not required, the number of parts is reduced, the assembly process is simplified, and the manufacturing cost can be reduced.

  The cylindrical member 40 may be formed by coating the surface of a cylindrical stainless steel tube with an abrasion-resistant resin made of, for example, cloth-containing phenol. As a result, as will be described later, the second stage cylinder 12 is disposed horizontally, and the outer surface of the second stage displacer 14 is brought to the inner surface of the second stage cylinder 12 by the weight of the second stage displacer 14. Even in the case of contact, wear of the second stage displacer 14 can be prevented.

  Further, instead of the outer peripheral surface of the second stage displacer 14, a spiral groove may be formed on the inner peripheral surface of the second stage cylinder 12. FIG. 4 is a schematic sectional view of another example of the configuration of the second stage displacer 14 together with the second stage cylinder 12 when the spiral groove 47a is formed on the inner peripheral surface of the second stage cylinder 12. Shown in

  The outer diameter of the portion below the opening 46 of the tubular member 40 may be slightly smaller than the outer diameter of the portion above the opening 46. At this time, a gap D <b> 22 is formed between the inner peripheral surface of the second stage cylinder 12 and the outer peripheral surface of the tubular member 40 in a portion below the opening 46. The gap D22 also forms a refrigerant gas flow path that connects the inside of the tubular member 40 and the expansion space 22.

  In the present embodiment, the second stage displacer 14 is coupled to the first stage displacer 13 via the coupling mechanism 50 so as to be rotatable about the central axis of the second stage displacer 14. That is, the second stage displacer 14 is coupled to the drive shaft Sh via the coupling mechanism 50 so as to be rotatable about the central axis of the second stage displacer 14.

  Further, in the present embodiment, the second stage displacer 14 is coupled to the first stage displacer 13 (that is, the drive shaft Sh) so as to be rotatable about the central axis of the second stage displacer 14, It is preferable that the second stage displacer 14 is connected so as to allow an inclination of the central axis of the second stage displacer 14 with respect to the first stage displacer 13 (that is, the drive shaft Sh).

  For example, a spherical bearing 50 having an inner ring 50a and an outer ring 50b that are spherically joined to each other is used as the coupling mechanism 50 that can be rotated around the central axis and that allows the inclination of the central axis to be allowed. be able to. By using the spherical bearing 50, rotation around the central axis and inclination of the central axis can be realized by one bearing mechanism. Therefore, the cylinder and the displacer of the GM refrigerator can be reduced in size and weight.

  As described in the first modification of the first embodiment, various bearings for connecting the second stage displacer 14 so as to be rotatable about the central axis of the second stage displacer 14, and the second stage displacer 14. Various bearings for coupling so as to allow the inclination of the central axis may be used in combination.

  Here, with reference to FIG.5 and FIG.6, the effect which the GM refrigerator which concerns on this Embodiment can prevent the partial wear of the outer peripheral surface of the 2nd stage displacer 14 is demonstrated, contrasting with a comparative example. .

  FIG. 5 is a diagram schematically showing an example in which the second stage cylinder 12 of the GM refrigerator according to the present embodiment is arranged horizontally. FIG. 5A is a front view, and FIG. 5B is a side view. FIG. 6 is a diagram schematically illustrating an example in which the second stage cylinder 12 of the GM refrigerator according to the comparative example is disposed horizontally. FIG. 6A is a front view, and FIG. 6B is a side view.

As shown in FIG. 6A, in the GM refrigerator according to the comparative example, the second stage displacer 14 and the first stage displacer 13 are coupled by a coupling mechanism 50A . The connecting mechanism 50A is configured by a general universal joint (universal joint). The universal joint is connected so as to allow an inclination of the center axis of the second stage displacer 14 with respect to the center axis of the first stage displacer 13 (that is, the drive shaft Sh).

  In the comparative example, when the second stage cylinder 12 is horizontally disposed, the outer peripheral surface of the second stage displacer 14 contacts the inner peripheral surface of the second stage cylinder 12 by the weight of the second stage displacer 14. To do. Further, since the second stage displacer 14 is not provided so as to be rotatable about the central axis of the second stage displacer 14, the same portion of the outer peripheral surface of the second stage displacer 14 is the second stage cylinder 12. Will come into contact with the inner peripheral surface. When the GM refrigerator is operated for a long time with the outer peripheral surface of the second stage displacer 14 being in contact with the inner peripheral surface of the second stage cylinder 12, as shown in FIG. Since only the (region I surrounded by the dotted line) wears, the outer peripheral surface of the second stage displacer 14 wears unevenly.

  On the other hand, in the present embodiment, as shown in FIG. 5A, for example, a spherical bearing is used as the coupling mechanism 50, so that the second stage displacer 14 is replaced with the first stage displacer 13 (that is, the drive shaft Sh). In addition, the second stage displacer 14 can be coupled to be rotatable about the central axis.

  When the second stage cylinder 12 is arranged horizontally, the outer peripheral surface of the second stage displacer 14 comes into contact with the inner peripheral surface of the second stage cylinder 12 by the weight of the second stage displacer 14. However, since the second stage displacer 14 rotates, the same portion of the outer peripheral surface of the second stage displacer 14 does not contact the inner peripheral surface of the second stage cylinder 12. That is, the portion of the outer peripheral surface of the second stage displacer 14 that contacts the inner peripheral surface of the second stage cylinder 12 is dispersed. Therefore, even if the GM refrigerator is operated for a long time with the outer peripheral surface of the second stage displacer 14 in contact with the inner peripheral surface of the second stage cylinder 12, as shown in FIG. Since the contact portions are dispersed, it is possible to prevent the outer peripheral surface of the second stage displacer 14 from being unevenly worn.

  In addition, when the second stage cylinder 12 is tilted with respect to the vertical direction and when the second stage cylinder 12 is disposed vertically, the same portion of the outer peripheral surface of the second stage displacer 14 is Contact with the inner peripheral surface of the second stage cylinder 12 can be prevented. And it can prevent that the outer peripheral surface of the 2nd step | level displacer 14 wears unevenly.

  Further, when the spherical bearing is used, the inclination of the central axis of the second stage displacer 14 with respect to the first stage displacer 13 (that is, the drive shaft Sh) can be allowed. Therefore, even if the central axis of the second stage cylinder 12 is slightly tilted with respect to the first stage cylinder 11 due to dimensional tolerance at the time of manufacture, the central axis of the second stage displacer 14 is set to the second stage. It can hold | maintain in parallel with the center axis | shaft of the eye cylinder 12, and it can prevent that the outer peripheral surface of the 2nd stage displacer 14 wears unevenly.

  However, when the inclination of the center axis of the second stage cylinder 12 with respect to the first stage cylinder 11 is extremely small, the second stage displacer 14 is connected to the first stage of the center axis of the second stage displacer 14. It does not need to be connected so as to allow inclination with respect to the displacer 13 (that is, the drive shaft Sh).

  Further, when the cylindrical member 40 is formed by coating the surface of a cylindrical stainless steel tube with a wear-resistant resin made of, for example, cloth-containing phenol, it further prevents uneven wear of the second stage displacer 14. can do.

In the present embodiment, the spiral groove 47 may be formed on the outer peripheral surface of the second stage displacer 14. When the second stage displacer 14 in which the spiral groove 47 is formed is reciprocated by the drive shaft Sh, a very small amount of refrigerant gas enters and exits the spiral groove 47 along with the reciprocation. Then, since the rotational driving force accompanying the flow of the refrigerant gas in the spiral groove 47 is applied to the second stage displacer 14, the second stage displacer 14 is automatically centered on the central axis of the second stage displacer 14. Is driven to rotate. Thereby, uneven wear of the second stage displacer 14 can be further prevented.
(First modification of the first embodiment)
Next, with reference to FIG. 7, the GM refrigerator which concerns on the 1st modification of 1st Embodiment is demonstrated. In the GM refrigerator according to the present modification, the connection mechanism that connects the second stage displacer 14 and the first stage displacer 13 (that is, the drive shaft Sh) is the first connection mechanism 51 and the second connection mechanism 52. It is comprised by.

  The GM refrigerator according to this modification is the same as the GM refrigerator according to the first embodiment except for the coupling mechanism. Therefore, in this modification, description about parts other than a connection mechanism is abbreviate | omitted.

  FIG. 7 is a schematic cross-sectional view showing the configuration of the second stage displacer 14 together with the second stage cylinder 12 in the GM refrigerator according to this modification.

  In this modification, the first connection mechanism 51 and the second connection mechanism 52 are connected in series in order from the first stage displacer 13 side to the second stage displacer 14 side.

  The first coupling mechanism 51 couples the second stage displacer 14 to the first stage displacer 13 (that is, the drive shaft Sh) so as to be rotatable about the central axis of the second stage displacer 14. .

As such a first connecting mechanism 51 for connecting rotatably about the central axis, for example, it has an inner ring 51a and an outer ring 51b, and the outer peripheral surface of the inner ring 51a and the inner peripheral surface of the outer ring 51b are joined. it can be used bearings being.

  The second coupling mechanism 52 is configured such that the second stage displacer 14 is connected to the first stage displacer 13 (that is, the driving shaft Sh), and the first stage displacer 13 (that is, the driving shaft) that is the central axis of the second stage displacer 14. It connects so that the inclination with respect to Sh) may be accept | permitted.

As such a second connecting mechanism 52 for connecting to permit the inclination of the central axis, it can be used, for example universal joints (universal joints).

  By using the first coupling mechanism 51 and the second coupling mechanism 52 in combination, rotation about the central axis and inclination of the central axis can be realized by simple coupling mechanisms, respectively. Therefore, the manufacturing cost of the GM refrigerator can be reduced.

  Also in this modified example, the second stage displacer 14 can freely rotate about the central axis of the second stage displacer 14, and therefore, uneven wear of the second stage displacer 14 can be prevented.

Further, since the inclination of the center axis of the second stage displacer 14 with respect to the first stage displacer 13 (that is, the drive shaft Sh) can be allowed, the center axis of the second stage displacer 14 is set to the center axis of the second stage cylinder 12. Can be held in parallel. Thereby, uneven wear of the second stage displacer 14 due to dimensional tolerances or the like can be prevented.
(Second modification of the first embodiment)
Next, with reference to FIG. 8, the GM refrigerator which concerns on the 2nd modification of 1st Embodiment is demonstrated. In the GM refrigerator according to this modification, no spiral groove is formed on either the outer peripheral surface of the second stage displacer 14 or the inner peripheral surface of the second stage cylinder 12.

  The GM refrigerator according to this modification is the same as the GM refrigerator according to the first embodiment except for the outer peripheral surface of the second stage displacer 14 and the inner peripheral surface of the second stage cylinder 12. . Therefore, in this modification, description about parts other than the outer peripheral surface of the second stage displacer 14 and the inner peripheral surface of the second stage cylinder 12 is omitted.

  FIG. 8 is a schematic cross-sectional view showing the configuration of the second stage displacer 14 together with the second stage cylinder 12 in the GM refrigerator according to this modification.

  In this modification, no spiral groove is formed on the outer peripheral surface of the tubular member 40. Further, no spiral groove is formed on the inner peripheral surface of the second stage cylinder 12. The gap D21 between the outer peripheral surface of the tubular member 40 and the inner peripheral surface of the second stage cylinder 12 is preferably 0.01 mm or more in order to stably drive the second stage displacer 14 back and forth. In order to prevent the refrigerant gas from flowing linearly in the axial direction through the gap D21, it is preferably 0.03 mm or less.

  In this modification, no spiral groove is formed on either the outer peripheral surface of the cylindrical member 40 or the inner peripheral surface of the second stage cylinder 12, but the second stage displacer 14 and the second stage displacer 14 are adjusted by adjusting the gap D21. It is possible to prevent the refrigerant gas from leaking through the gap D21 with the second stage cylinder 12. As a result, since it is not necessary to accommodate the seal ring in the gap D21 between the second stage displacer 14 and the second stage cylinder 12, the thickness of the side wall of the cylindrical member 40 can be reduced, and the hollow space 24 can be reduced. Since the volume of can be increased, the cold storage material to be accommodated can be increased, and the refrigerating capacity can be increased. Further, since the seal ring is not required, the number of parts is reduced, the assembly process is simplified, and the manufacturing cost can be reduced.

  Also in this modified example, the second stage displacer 14 can freely rotate about the central axis of the second stage displacer 14, and therefore, uneven wear of the second stage displacer 14 can be prevented.

Further, since the inclination of the center axis of the second stage displacer 14 with respect to the first stage displacer 13 (that is, the drive shaft Sh) can be allowed, the center axis of the second stage displacer 14 is set to the center axis of the second stage cylinder 12. Can be held in parallel. Thereby, uneven wear of the second stage displacer 14 due to dimensional tolerances or the like can be prevented.
(Second Embodiment)
Next, with reference to FIG. 9, the GM refrigerator which concerns on 2nd Embodiment is demonstrated. In the GM refrigerator according to the present embodiment, a third connection mechanism 53 that connects the first-stage displacer 13 and the drive shaft Sh is provided.

  The GM refrigerator according to the present embodiment can be configured in the same manner as the GM refrigerator according to the first embodiment, except for the third coupling mechanism 53. Therefore, in the present embodiment, description of parts other than the third coupling mechanism 53 is omitted.

  FIG. 9 is a schematic cross-sectional view showing the configuration of the first stage displacer 13 together with the first stage cylinder 11 in the GM refrigerator according to the present embodiment.

  The first stage displacer 13 is coupled to the drive shaft Sh via the third coupling mechanism 53 so as to be rotatable about the central axis of the first stage displacer 13.

  Further, in the present embodiment, the first stage displacer 13 is coupled to the drive shaft Sh so as to be rotatable about the central axis of the first stage displacer 13 and the central axis of the first stage displacer 13. It is preferable that they are connected so as to allow inclination with respect to the drive shaft Sh.

As such a third coupling mechanism 53 that can be rotated about the central axis and that allows the inclination of the central axis to be allowed, a spherical bearing having an inner ring 53a and an outer ring 53b that are spherically connected to each other, for example. it can be used immediately. By using the spherical bearing 53, rotation around the central axis and inclination of the central axis can be realized by one bearing mechanism. Therefore, the part reciprocally driven in the GM refrigerator can be reduced in size and weight.

  Also in the present embodiment, the first stage displacer 13 can freely rotate about the central axis of the first stage displacer 13, so that uneven wear of the first stage displacer 13 can be prevented.

  Further, since the inclination of the center axis of the first stage displacer 13 with respect to the drive shaft Sh can be allowed, the center axis of the first stage displacer 13 can be held in parallel with the center axis of the first stage cylinder 11. Thereby, uneven wear of the first stage displacer 13 due to dimensional tolerances or the like can be prevented.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be modified or changed.

DESCRIPTION OF SYMBOLS 10 Compressor 11 1st stage cylinder 12 2nd stage cylinder 13 1st stage displacer 14 2nd stage displacer 15 Crank mechanism 16 Refrigerant gas flow path 17, 18 Cool storage material 19, 20 Heat station 21, 22 Expansion space 23, 24 Hollow space (refrigerant gas flow path)
30, 40 Tubular member 31 Flange 32, 34, 46 Opening 33, 41 Lid member 35, 47, 47a Spiral groove 50-53 Connection mechanism

Claims (4)

A cylinder,
A refrigerant gas flow path provided in the cylinder so as to be capable of reciprocating along the cylinder, forming an expansion space at one end of the cylinder, and supplying and discharging a refrigerant gas into the expansion space inside. A cylindrical displacer formed with
A drive shaft for reciprocating the displacer;
Cold storage stored in the refrigerant gas flow path for storing cold heat generated by expanding the refrigerant gas supplied to the expansion space when the displacer is reciprocated along the cylinder by the drive shaft. With materials,
The displacer is a regenerator-type refrigerator that is connected to the drive shaft so as to be rotatable about a central axis of the displacer.   The displacer is coupled to the drive shaft so as to be rotatable about a central axis of the displacer, and is coupled to allow an inclination of the central axis of the displacer with respect to the drive shaft. The regenerator type refrigerator described.   The regenerator type refrigerator according to claim 2, wherein the displacer is connected to the drive shaft via a spherical bearing.   The regenerator type refrigerator according to any one of claims 1 to 3, wherein a helical groove is formed on an outer peripheral surface of the displacer or an inner peripheral surface of the cylinder.

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