JP2009222312A - Magnetic circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic circuit capable of stabilizing cooling performance of a refrigerator for a long time. <P>SOLUTION: The magnetic circuit 40 for the refrigerator 1 having a compressor 10 for compressing working fluid and a cold head 20 for expanding the working fluid to generate a refrigeration action is provided with: a cylindrical yoke part 41; a magnet part 42 arranged on the inner peripheral face of the yoke part 41 and extended to a central axis direction X1; a sleeve 43 for pinching the magnet part 42 with the yoke part 41; a coil 44 reciprocated in parallel with the central axis direction X1; and a nonslip member 45 for braking the operation of the magnet part 42 in the central axis direction X. In the magnetic circuit 40, one end of the magnet part 42 is made abut on a step part 41a and the other on the nonslip member 45. The nonslip member 45 is fixed to one end of the yoke 41 by screws 46. Thus, the magnet part 42 can be fixed to the yoke part 41 without using an adhesive. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnetic circuit in a refrigerator for generating a cryogenic temperature.

  There exists a Stirling refrigerator (for example, patent document 1) as a refrigerator for producing cryogenic temperature. The Stirling refrigerator includes a compressor that compresses the working fluid, a cold head that expands the working fluid after the compressed working fluid is flown therein to generate a refrigeration action, and a guide flow path that connects them. ing. The compressor includes a pair of pistons that can reciprocate along a central axis X, and a fixed cylinder that accommodates the pair of pistons.

In such a refrigerator, as shown in FIG. 6, a cylindrical yoke portion 61 disposed on the outer periphery of the fixed cylinder portion 60 and an inner peripheral surface S of the yoke portion 61 (in Patent Document 1, the outer periphery of the yoke portion). A magnetic circuit 64 including a ring-shaped magnet portion 62 bonded and fixed to the surface) by an adhesive G, and a coil 63 reciprocating in a direction parallel to the central axis X along the inner peripheral surface of the magnet portion 62. Is provided. When the magnetic circuit 64 is energized, the coil 63 is moved, and the piston 65 connected to the coil 63 is reciprocated along the central axis X to compress the working fluid. Such a magnetic circuit is arranged in a working fluid such as helium gas.
JP 09-089400 A

  However, in the above-described magnetic circuit in the conventional refrigerator, the magnet portion is bonded to the yoke portion with an adhesive. For this reason, the volatile components originally contained in the adhesive of the magnetic circuit and the mixed air at the time of bonding work are gradually ejected as outgas as time passes, and are adhered and solidified on the fluid flow path or the piston sliding surface. The operation of the refrigerator may be affected. As a result, the cooling performance may be reduced.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetic circuit capable of stabilizing the refrigeration performance of a refrigerator over a long period of time.

  A magnetic circuit according to the present invention includes a compression unit that operates a piston to compress a working fluid, and a refrigeration unit that receives a working fluid compressed by the compression unit and expands the working fluid to generate a refrigeration action. It is a magnetic circuit in the refrigerator provided. This magnetic circuit is disposed in close contact with a cylindrical yoke portion that is fixedly disposed inside at least one of the compression portion and the freezing portion, and any one of the inner peripheral surface and the outer peripheral surface of the yoke portion. And a cylindrical sleeve that extends in the axial direction of the yoke portion and has a ring-shaped cross section, and a cylindrical sleeve that is disposed in close contact with the circumferential surface that is the surface of the magnet portion and clamps the magnet portion together with the yoke And a coil that reciprocates in the axial direction along the circumferential surface that is the surface of the sleeve, and a retaining member that brakes the operation of the magnet portion in the axial direction.

  In this magnetic circuit, the magnet portion is not fixed to the yoke portion with an adhesive, but the operation of the magnet portion is braked by a retaining member. Thereby, the outgas caused by the adhesive is prevented. As a result, the cooling performance of the refrigerator can be stabilized over a long period of time. Here, the magnet portion having a “ring-shaped cross section” is not limited to a single magnet having a ring shape in cross section, but as a whole having a substantially ring shape by a plurality of magnets having a cross section formed in an arc shape. As long as it includes a magnet part capable of forming a cross section and the magnetic circuit satisfies a predetermined performance, a part of the arc-shaped magnet may be missing.

  In addition, one end of the magnet portion is in contact with a stepped portion provided on the circumferential surface of the yoke, and the other end of the magnet portion is in contact with a retaining member, and the retaining member is opposite to the stepped portion in the axial direction. It is preferable to be fixed to one end of the yoke portion located on the side by a fixing member. Thereby, the magnet part can be fixed to the yoke part by simple fixing means such as fixing the yoke part and the retaining member with the fixing member.

  Moreover, it is preferable that the sleeve and the retaining member are integrally formed. Thereby, a magnet part can be fixed to a yoke part, without increasing a number of parts so much.

  The retaining member has a ring shape, and it is preferable that the retaining member is formed with a gas vent hole at a contact portion with the magnet portion. As a result, the gas remaining between the magnet portion and the sleeve can be easily discharged at the time of manufacturing the magnetic circuit, and deterioration of the refrigerating capacity due to such residual gas can be prevented. As a result, the cooling performance of the refrigerator can be stabilized for a longer period.

  It is preferable that the fixing member is a screw, and the retaining member is screwed to one end of the yoke portion. In this case, the retaining portion can be fixed to the yoke portion and the magnet portion can be fixed to the yoke portion with a simple configuration.

  It is preferable that at least one of the retaining member and the yoke portion is formed with a gas vent hole for discharging residual gas in the screw hole for screwing. This makes it possible to easily discharge the residual gas in the screw hole, which is required when the retaining portion is fixed to the yoke portion with a screw, at the time of manufacturing the magnetic circuit, and to deteriorate the refrigeration capacity due to the residual gas in the screw hole. Can be prevented. As a result, the cooling performance of the refrigerator can be stabilized for a longer period.

  The magnetic circuit according to the present invention includes a cylindrical cylinder portion that is coaxially disposed inside the yoke portion and has a yoke portion and ends connected to each other by a connecting portion formed on the opposite side of the coil entrance. The magnet portion is disposed in close contact with the inner peripheral surface of the yoke portion, and a space in which the coil reciprocates is defined by the inner peripheral surface of the sleeve disposed on the surface of the magnet portion and the outer peripheral surface of the cylinder portion. It is preferable that a protrusion projecting to the outer peripheral surface of the cylinder is formed at one end of the sleeve on the connecting portion side. If it does in this way, the insertion space of a coil can be easily maintained above a predetermined value. As a result, the coil can be stably inserted and removed over a long period of time.

  It is more preferable that a through-hole penetrating to the back surface is formed in the connecting portion, and the protruding portion of the sleeve has a notch at a location corresponding to the through-hole. In this way, since the gas compressed by inserting the coil is easily discharged to the outside, the operation of the coil can be further stabilized.

  ADVANTAGE OF THE INVENTION According to this invention, the magnetic circuit which can stabilize the cooling performance of a refrigerator over a long period can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a cross-sectional view showing the overall configuration of the refrigerator according to the present embodiment. The refrigerator 1 is a Stirling refrigerator that uses a Stirling cycle, and includes a compressor (compression unit) 10, a cold head (freezing unit) 20, and a guide channel 30 that connects them.

  As shown in FIG. 1, the compressor 10 compresses a working fluid such as helium gas by the first and second pistons 11 and 12, and the working fluid compressed by the compressor 10 passes through the guide channel 30. And sent to the cold head 20. The compressor 10 includes a first piston 11 that extends along the reference central axis X1 direction, a second piston 12 that extends along the central axis X1 direction, and is provided to face the first piston 11. A first cylinder portion 13 that accommodates the first piston 11 and forms the first compression space S1, and a second cylinder portion 14 that accommodates the second piston 12 and forms the second compression space S2. And a magnetic circuit 40 for reciprocating the first piston 11 along the direction of the central axis X1, and a magnetic circuit 50 for reciprocating the second piston 12 along the direction of the central axis X1. Yes.

  The cold head 20 is refrigerated by expanding the compressed working fluid by reciprocating the first and second displacers 22 and 23 in the first and second cylinder portions 24 and 25 via the working rod 21. It is a multistage cold head that produces an action. The cold head 20 includes a working rod 21 that reciprocates the first displacer 22 and the second displacer 23 in the direction of the central axis X2, and a first rod that is connected to the working rod 21 and extends along the direction of the central axis X2. The first displacer 22, the second displacer 23 connected to the first displacer 22 and extending along the direction of the central axis X 2, and the first displacer 22 is accommodated to form a first expansion space S 3. Cylinder portion 24, a second cylinder portion 25 that accommodates the second displacer 23 to form the second expansion space S4, and a magnetic circuit 26 for driving the operating rod 21 in the direction of the central axis X2. A drive unit 27 and a vibration suppression unit 29 that forms a pair with the drive unit 27 and suppresses vibrations by the drive unit 27 by driving by the magnetic circuit 28 are provided. There.

  In the refrigerator 1 having such a configuration, by driving the magnetic circuit 40, the first piston 11 moves to the center side, which is the direction in which the working fluid is compressed, and the compressor 10 operates in the compression space S1. Compress the fluid. Similarly, by driving the magnetic circuit 50, the second piston 12 is moved to the center side, and the working fluid is compressed in the compression space S2 of the compressor 10. The working fluid compressed in the compression spaces S1 and S2 is sent to the expansion spaces S3 and S4 of the cold head 20 through the guide channel 30 at a predetermined timing. Then, the first and second displacers 22 and 23 are driven to the drive unit 27 side by the operating rod 21 so that the expansion spaces S3 and S4 expand. Due to the expansion of the working fluid in the expansion spaces S3 and S4, a refrigeration action occurs in the cold head 20. Thereafter, the expanded working fluid is returned to the compressor 10 through the guide channel 30.

  Here, the magnetic circuits 40 and 50 for moving the first and second pistons 11 and 12 by a predetermined amount will be described with reference to FIGS. 2 is a sectional view of the magnetic circuit according to the present embodiment, FIG. 3 is a sectional view taken along line III-III in FIG. 2, and FIG. 4 is a sectional view taken along line IV-IV in FIG. 5 is a schematic side view in FIG. The magnetic circuits 40 and 50 are arranged in a predetermined concentration of helium gas.

  As shown in FIGS. 2 to 5, the magnetic circuit 40 includes a yoke portion 41 having a cylindrical shape, and a plurality of magnets 42 a having a circular arc cross section disposed in close contact with the inner peripheral surface of the yoke portion 41. A ring-shaped magnet portion 42 having a cross-section, a cylindrical sleeve 43 for holding the magnet portion 42 in a radial direction with respect to the inner peripheral surface of the yoke portion 41, and an inner periphery of the sleeve 43 in a direction parallel to the central axis X1. A coil 44 that reciprocates along the surface, a ring-shaped retaining member 45 that brakes the movement of the magnet portion 42 in the direction of the central axis X1, and a screw (fixing portion) that fixes the retaining member 45 to one end of the yoke portion 41. ) 46, 46, 46. In the present embodiment, the sleeve 43 and the retaining member 45 are integrally formed to constitute a sleeve integrated retaining member 47. The yoke portion 41, the magnet portion 42, the sleeve-integrated retaining member 47, and the coil 44 are arranged so as to be coaxial with the central axis X1.

  The yoke portion 41 has a cylindrical shape, and a step portion 41a for locking a part of the end surface of the magnet portion 42 is formed on the inner peripheral surface thereof. Screw holes 41b, 41b, 41b for screwing screws 46 are spaced at 120 ° intervals at one end of the yoke portion 41 located on the opposite side of the step portion 41a and the central axis X1 direction. Three places are formed. Further, a gas vent hole 41c for extracting residual gas in the screw hole 41b is formed from the outer peripheral surface of the yoke portion 41 to the screw hole 41b. The yoke portion 41 having such a configuration is integrated with the other end of the yoke portion 41 being connected to the first cylinder portion 13 by the connecting portion 48 to form a main body portion 49. The integrated main body 49 is made of a rolled steel material (SS material), cementule, or the like.

  A space S <b> 5 is formed between the inner peripheral surface of the sleeve 43 that holds the magnet portion 42 between the yoke portion 41 that constitutes the main body portion 49 and the outer peripheral surface of the first cylinder portion 13 that constitutes the main body portion 49. Has been. As shown in FIG. 2, the coil 44 can enter the space S5 in a state in which the coil 44 can reciprocate in a direction parallel to the central axis X1. As shown in FIGS. 2 and 4, the connecting portion 48 is formed with through holes 48a,... Continuous from the space S5, and the direction of entry when the coil 44 enters the space S5. The gas compressed in the front is discharged to the outside.

  Each of the plurality of magnets 42a,... Constituting the magnet portion 42 has an arc shape in cross section and is constituted by an arc piece extending in the direction of the central axis X1 so as to form a ring shape as a whole. It has become. Each of the magnets 42a having such a shape is coated with titanium nitride on the entire surface, so that particles and gas contained in the magnet 42a are not easily released to the outside. Such magnets 42 a,... Are brought into contact with one end on the connecting portion 48 side so that a part of the end surface is caught on the stepped portion 41 a provided on the inner peripheral surface of the yoke portion 41. On the other hand, the other end of the magnets 42 a,... Is in contact with the entire back surface of the retaining member 45. As a result, the magnets 42a,... Constituting the magnet part 42 are sandwiched between the step part 41a and the retaining member 45, and the movement in the direction of the central axis X1 is braked. The magnets 42a,... Constituting the magnet part 42 are also sandwiched between the yoke part 41 and the sleeve 43, and the magnet part 42 is braked in the radial direction toward the center of the central axis X1. The By such braking in the two directions, the magnet portion 42 is fixed to the yoke portion 41 so as to be substantially integrated with the yoke portion 41.

  The entire sleeve-integrated retaining member 47 including the sleeve 43 and the retaining member 45 is made of stainless steel. As shown in FIG. 5, the retaining member 45 is formed with three through holes 45a, 45a, 45a for the screws 46 at 120 ° intervals so as to be evenly spaced in the circumferential direction. The screw 46 is screwed into a screw hole 41b formed on the end surface of the yoke portion 41 through the through hole 45a. Further, the retaining member 45 is formed with a plurality of gas vent holes 45b,... Penetrating to the location on the back surface where the magnet portion 42 abuts. Further, as shown in FIG. 2, the retaining member 45 is formed with gas vent holes 45c, 45c, 45c penetrating from the side with respect to the screw through hole 45a.

  At one end of the sleeve 43 on the side of the connecting portion 48, a protrusion 43 a that protrudes inward to the outer peripheral surface of the first cylinder portion 13 is formed. As shown in FIG. 3, the protrusion 43a is formed with a notch 43b at a location corresponding to the through hole 48a, and has a substantially ring-shaped cross section with a partially cutout inner peripheral side. ing. The coil 44 is formed by winding a conducting wire around a cylindrical main body, and is coaxially connected to the first piston 11 shown in FIG. When the coil 44 reciprocates in the space S5 along the inner peripheral surface of the sleeve 43 in a direction parallel to the central axis X1, the connected first piston 11 reciprocates in the first cylinder portion 13. The working fluid is compressed. In this way, the magnetic circuit 40 is configured. The magnetic circuit 50 has a configuration similar to that of the magnetic circuit 40.

  Next, a method for manufacturing the magnetic circuits 40 and 50 will be described.

  First, a main body portion 49 including a yoke portion 41, a first cylinder portion 13, and a connecting portion 48 is prepared. Subsequently, a plurality of magnets 42a,... Are inserted along the inner peripheral surface of the yoke portion 41 from the opening end of the main body 49 (advancing entrance of the coil 44), and one end of each magnet 42a,. Is brought into contact with the stepped portion 41a. Next, a sleeve-integrated retaining member 47 in which the sleeve 43 and the retaining member 45 are integrated is inserted from the opening end of the main body 49 to brake the radial operation of the magnet 42a and the central axis X1. Directional motion is also braked. After inserting the sleeve-integrated retaining member 47, the screw hole 41b of the yoke part 41 and the through hole 45a of the retaining member 45 are aligned, and both are fixed by the screw 46. By this fixing, the magnet part 42 composed of the magnets 42 a,... Is fixed to the yoke part 41. Then, the coil 44 is installed in a space S5 defined by the inner peripheral surface of the sleeve 43 and the outer peripheral surface of the first cylinder portion 13 so as to reciprocate in a direction parallel to the central axis X1. Thereby, the magnetic circuit 40 is manufactured. The manufacturing method of the magnetic circuit 50 is the same. Thereafter, the magnetic circuits 40 and 50 are arranged at predetermined positions of the compressor 10, the inside of the compressor 10 is evacuated to discharge residual gas, etc., and filled with helium gas of a predetermined concentration.

  As described in detail above, in the magnetic circuits 40 and 50 according to the present embodiment, the magnet portion 42 and the yoke portion 41 are not bonded and fixed by the adhesive, but the yoke portion 41 and the retaining member 45 are fixed by the screw 46. By doing so, the magnet part 42 is fixed to the yoke part 41. As a result, the generation of the outgas caused by the adhesive is prevented. As a result, the cooling performance of the refrigerator 1 can be stabilized over a long period of time.

  The yoke portion 41 and the retaining member 45 are formed with screw holes 41b for screwing and gas vent holes 41c and 45c for discharging residual gas in the through holes 45a. Further, the retaining member 45 is also formed with a gas vent hole 45b for discharging residual gas at a position where it comes into contact with the magnet portion. Thereby, the residual gas in the screw holes 41b and 45a, the residual gas between the magnet part 42 and the sleeve 43, etc. can be easily discharged at the time of manufacturing the magnetic circuits 40 and 50. As a result, generation of outgas due to these residual gases is further prevented.

  Each magnet 42a,... Is coated with titanium nitride. This makes it difficult for particles and gas present inside the magnet 42a to be released to the outside. As a result, generation of outgas is further prevented.

  The connecting portion 48 is formed with a through hole 48a that extends from the space S5. Thereby, since the gas compressed by inserting the coil 44 is easily discharged | emitted outside, the operation | movement of the coil 44 can be stabilized. A protrusion 43 a that protrudes inward to the outer peripheral surface of the first cylinder portion 13 is formed at one end of the sleeve 43 on the connection portion 48 side. Thereby, the insertion space of the coil 44 can always be kept above a predetermined value, and the operation of the coil can be further stabilized over a long period of time.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the above embodiment, the sleeve 43 and the retaining member 45 are integrated, but the sleeve and the retaining member may be configured as separate members. In this case, it is preferable that the retaining member is made of a nonmagnetic SUS material and the sleeve is made of a rolled steel material (SS material). In the above embodiment, the magnet portion 42 is provided on the inner peripheral surface of the yoke portion 41. However, the yoke portion is circumferentially contacted with the outer periphery of the first cylinder, and the coil is coaxially formed on the outer side of the yoke portion. In the type of magnetic circuit to be arranged, a magnet part may be provided on the outer peripheral surface of the yoke part.

  Moreover, in the said embodiment, although magnet 42a, ... was provided so that it might become a perfect ring shape, as long as it has predetermined performance, a part of magnet may be applied. In the above embodiment, the retaining member 45 is formed in a ring shape, but the shape is not particularly limited as long as the movement of the individual magnets 42a in the direction of the central axis X1 can be braked. Furthermore, the configuration of the magnetic circuits 40 and 50 described in the above embodiment may be applied to the magnetic circuit of the cold head 20, and is used for a refrigerator other than a Stirling refrigerator such as a GM refrigerator or a JT compressor. May be.

It is the schematic which shows typically the structure of the refrigerator which consists of a compressor and a cold head. It is sectional drawing of the magnetic circuit which concerns on embodiment. It is the III-III sectional view taken on the line in FIG. It is the IV-IV sectional view taken on the line in FIG. FIG. 3 is a schematic side view in FIG. 2. It is sectional drawing of the conventional magnetic circuit.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Refrigerator, 10 ... Compressor (compression part), 11 ... 1st piston, 12 ... 2nd piston, 13 ... 1st cylinder, 14 ... 2nd cylinder, 20 ... Cold head (refrigeration part) , 26, 28, 40, 50 ... magnetic circuit, 41 ... yoke part, 41a ... step part, 41c, 45b, 45c ... gas vent hole, 42 ... magnet part, 42a ... magnet, 43 ... sleeve, 43a ... projection, 43b ... Notch, 44 ... Coil, 45 ... Retaining member, 46 ... Screw (fixing member), 47 ... Sleeve-integrated retaining member, 48 ... Connecting portion, 48a ... Through hole, S1, S2 ... Compression space, S3 , S4 ... expansion space, S5 ... space, central axis ... X1, X2.

Claims (9)

A refrigerator comprising: a compression unit that operates a piston to compress a working fluid; and a refrigeration unit that receives the working fluid compressed by the compression unit and expands the working fluid to generate a refrigeration operation. A magnetic circuit,
A cylindrical yoke portion fixedly disposed inside at least one of the compression portion and the freezing portion; and
A magnet portion that is arranged in close contact with any one of the inner circumferential surface and the outer circumferential surface of the yoke portion, extends in the axial direction of the yoke portion, and has a ring shape in cross section;
A cylindrical sleeve that is disposed in close contact with the peripheral surface of the magnet portion and sandwiches the magnet portion together with the yoke;
A coil that reciprocates in the axial direction along a circumferential surface that is a surface of the sleeve;
A retaining member that brakes the movement of the magnet portion in the axial direction;
A magnetic circuit comprising:   One end of the magnet portion is in contact with a step portion provided on the peripheral surface of the yoke, and the other end of the magnet portion is in contact with the retaining member, and the retaining member is connected to the step portion. The magnetic circuit according to claim 1, wherein the magnetic circuit is fixed to one end of the yoke portion located on the opposite side in the axial direction by a fixing member.   The magnetic circuit according to claim 2, wherein the sleeve and the retaining member are integrally formed. The retaining member has a ring shape,
The magnetic circuit according to claim 2, wherein the retaining member is formed with a gas venting hole at a contact position with the magnet portion. The fixing member is a screw,
The magnetic circuit according to claim 2, wherein the retaining member is screwed to one end of the yoke portion.   6. A magnetic circuit according to claim 5, wherein at least one of the retaining member and the yoke part is formed with a gas venting hole for discharging residual gas in the screw hole for screwing. . A cylindrical cylinder portion that is coaxially disposed inside the yoke portion and that is connected to the yoke portion and ends by a connecting portion formed on the opposite side of the entrance of the coil;
The magnet portion is disposed in close contact with the inner peripheral surface of the yoke portion, and the coil reciprocates between an inner peripheral surface of the sleeve and an outer peripheral surface of the cylinder portion disposed on the surface of the magnet portion. Demarcating the moving space,
The magnetic circuit according to any one of claims 2 to 6, wherein a protrusion that protrudes to an outer peripheral surface of the cylinder is formed at one end of the sleeve on the side of the connecting portion. The connecting portion is formed with a through hole penetrating to the back surface,
The magnetic circuit according to claim 7, wherein the projecting portion of the sleeve has a notch at a location corresponding to the through hole. The said compression which has the magnetic circuit as described in any one of Claims 1-8, moves the said piston arrange | positioned coaxially with the said coil by the said magnetic circuit to the said axial direction, and compresses the said working fluid. And
A refrigerating machine comprising: the refrigeration unit that causes the working fluid compressed by the compression unit to flow from the compression unit and expands the working fluid to generate a refrigeration operation.

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