JP2009022087A - Linear motor, and stirling freezer equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear motor which is possible of downsizing and can be manufactured inexpensively. <P>SOLUTION: The linear motor 1A is equipped with a moving member 10, which includes an output shaft 12 and a permanent magnet 16, and a stator 20, which includes a coil 24 and a yoke 22. The stator 10 has a plurality of yokes 22 which are provided apart in the circumferential direction of the output shaft 12. Each of the plurality of yokes 22 has magnetic pole groups 23A and 23B including a pair of magnetic poles 23a and 23b being excited into reverse polarity in sections opposed to adjacent yokes, and a pair of magnetic poles 23a and 23b included in each of the magnetic pole groups 23A and 23B are counterposed to each other in the axial direction of the output shaft 12. The permanent magnet 16 is arranged between the magnetic pole groups 23A and 23B as well as between adjacent yokes 22. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a linear motor configured so that an output shaft can reciprocate in an axial direction, and a Stirling refrigerator including the linear motor as a driving means for a piston.

  Conventionally, in order to compress / expand a working medium sealed in a casing by using a piston, a Stirling refrigerator having a linear motor as a driving means for the piston is known. For example, Japanese Patent Application Laid-Open No. 2004-332675 (Patent Document 1) discloses a cylinder disposed in a pressure vessel as a casing, a piston and a displacer fitted into the cylinder, and driving the piston. A Stirling refrigerator including a linear motor is disclosed.

Various types of linear motors are known. To classify these motors, a permanent magnet is disposed on the mover provided with the output shaft, and the stator is provided with a yoke and a coil. A coil is disposed on a magnet type (see, for example, Patent Document 1 and Japanese Patent Application Laid-Open No. 2001-352736 (Patent Document 2), etc.) and a mover provided with an output shaft, and a permanent magnet and a yoke are provided on the stator. Of a so-called moving coil type (see, for example, JP-A-9-158827 (Patent Document 3)). In such a linear motor, generally, the yoke provided on the stator is constituted by an inner yoke and an outer yoke, and the inner yoke is provided on the inner peripheral side of the permanent magnet or coil provided on the mover, and the outer yoke is provided. Is arranged on the outer peripheral side of a permanent magnet or a coil provided on the mover.
JP 2004-332675 A JP 2001-352736 A Japanese Patent Laid-Open No. 9-158827

  However, in such a configuration, since the yoke is composed of an inner yoke and an outer yoke, the size of the linear motor increases in the radial direction, and the size of the device increases. Or since it had to be formed in an arc shape, there existed a problem that manufacturing cost increased. In particular, with respect to the former problem, it is necessary to form the inner yoke and the outer yoke to be considerably thicker in order to prevent magnetic saturation in the yoke, so that the linear motor is increased in size in the radial direction. The result was

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a linear motor that can be miniaturized and can be manufactured at low cost, and a Stirling refrigerator including the linear motor. And

  The linear motor based on this invention is provided with the needle | mover containing an output shaft and a permanent magnet, and the stator containing a coil and a yoke, and the said stator follows the circumferential direction of the said output shaft so that the said output shaft may be surrounded. It is provided. The stator has a first yoke portion and a second yoke portion that are spaced apart along the circumferential direction of the output shaft. The first yoke part includes a first magnetic pole group including a pair of magnetic poles excited in opposite polarities at a portion facing the second yoke part, and the pair of magnetic poles included in the first magnetic pole group includes Further, they are arranged to face each other along the axial direction of the output shaft. The second yoke portion includes a second magnetic pole group including a pair of magnetic poles excited in opposite polarities at a portion facing the first yoke portion, and the pair of magnetic poles included in the second magnetic pole group includes Further, they are arranged to face each other along the axial direction of the output shaft. The permanent magnet is disposed between the first yoke portion and the second yoke portion and between the first magnetic pole group and the second magnetic pole group.

  With this configuration, the two yokes, the inner yoke and the outer yoke arranged in the radial direction of the output shaft, which are necessary in the conventional linear motor, are formed by one yoke arranged in the radial direction of the output shaft. It will be over. Accordingly, the size of the apparatus in the radial direction can be greatly reduced, and the number of parts can be reduced as compared with the conventional case, and thus the manufacturing cost can be suppressed. Also, when it is necessary to increase the thickness of the yoke to prevent magnetic saturation, the direction in which the thickness should be increased coincides with the circumferential direction of the output shaft. It does not become.

  In the linear motor according to the present invention, the permanent magnet is preferably arranged so that the N pole and the S pole are aligned along the circumferential direction of the output shaft. One of the pair of magnetic poles included in one magnetic pole group and one of the pair of magnetic poles included in the second magnetic pole group disposed opposite to the one magnetic pole group are excited to have opposite polarities. It is desirable that

  In the linear motor according to the present invention, the stator is preferably composed of a plurality of divided stators including a coil and a yoke. In that case, the first yoke portion and the above It is desirable that the second yoke portion is constituted by a yoke included in each of a pair of adjacent divided stators.

  Moreover, in the linear motor based on the said invention, it is preferable that the said needle | mover has an attachment part for fixing the said permanent magnet to the said output shaft, In that case, the said attachment part is It is desirable that the surface of the permanent magnet in the circumferential direction of the output shaft is exposed by sandwiching the permanent magnet in the axial direction of the output shaft.

  Moreover, in the linear motor based on the said invention, it is preferable that the said permanent magnet is flat form.

  A Stirling refrigerator according to the present invention includes any one of the above-described linear motors as piston driving means.

  By comprising in this way, it can be set as the Stirling refrigerator which is small and can be manufactured cheaply.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the linear motor which can be reduced in size and can be manufactured cheaply, and a Stirling refrigerator provided with the same.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments described below, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated. Note that in the embodiments described below, when referring to the number, amount, and the like, the scope of the present invention is not necessarily limited to the number, amount, and the like unless otherwise specified. In the following embodiments, each component is not necessarily essential for the present invention unless otherwise specified. In addition, when there are a plurality of embodiments below, it is planned from the beginning to appropriately combine the configurations of the embodiments unless otherwise specified.

(Embodiment 1)
FIG. 1 is a perspective view showing an external structure of a linear motor according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the linear motor according to the present embodiment cut along a plane perpendicular to the axial direction at the axial center position. First, the structure of the linear motor 1A in the present embodiment will be described in detail with reference to these drawings.

  As shown in FIGS. 1 and 2, the linear motor 1 </ b> A in the present embodiment includes a mover 10 and a stator 20. The mover 10 mainly includes an output shaft 12 and a permanent magnet 16. The stator 20 is provided in a substantially cylindrical shape along the circumferential direction of the output shaft 12 so as to surround the output shaft 12, and is configured by a plurality of divided stators. In linear motor 1A in the present embodiment, stator 20 is configured by four divided stators, and each divided stator includes one yoke 22 and one coil 24, respectively.

  The output shaft 12 is disposed in the center of the mover 10 and extends in the directions of arrows A1 and A2 shown in FIG. The permanent magnets 16 are provided at four locations on the outer periphery of the output shaft 12, and output via a mounting portion 14 having a substantially cross shape in plan view formed so as to fill a space between the output shaft 12 and the permanent magnet 16. It is fixed to the shaft 12. The permanent magnet 16 is a so-called plate magnet having a flat plate shape, and is arranged such that its main surface faces the circumferential direction of the output shaft 12. The N pole 16 a and the S pole 16 b of the permanent magnet 16 are arranged so that these magnetic poles are arranged in the circumferential direction of the output shaft 12. The magnetic poles of the permanent magnets 16 that are adjacent to each other in the circumferential direction of the output shaft 12 are arranged so that the same magnetic poles face each other in the circumferential direction.

  Further, in the linear motor 1 </ b> A according to the present embodiment, these permanent magnets 16 are sandwiched by the attachment portion 14 in the axial direction of the output shaft 12. Accordingly, the pair of surfaces in the circumferential direction of the output shaft 12 of the permanent magnet 16 are both exposed. In manufacturing the movable element 10 having such a configuration, when the mounting portion 14 is injection-molded using a resin material, insert molding is performed so that the output shaft 12 and the permanent magnet 16 are integrated. Can be easily manufactured.

  Each of the four divided stators constituting the stator 20 includes a frame-like yoke 22 formed by curving in an arc shape so as to surround the output shaft 12, and a columnar portion 22 a provided at the central position of the yoke 22. The coil 24 is wound around (see FIG. 2). The columnar portion 22a extends along the axial direction of the output shaft 12, and a coil 24 is formed by winding a lead wire around the columnar portion 22a. As the yoke 22, a laminated electromagnetic steel sheet or the like is preferably used.

  Each of the yokes 22 included in each of the divided stators has magnetic pole groups 23A and 23B including a pair of magnetic poles 23a and 23b in portions facing the adjacent yokes. More specifically, it is formed by providing gap portions at predetermined positions on one end and the other end along the circumferential direction of the output shaft 12 of the yoke 22 formed in a frame shape, and providing this gap portion. A pair of edge portions along the axial direction of the output shaft 12 of the frame-shaped yoke 22 are used as magnetic poles 23 a and 23 b, so that each yoke 22 has a pair of magnetic pole groups 23 A and 23 A in the circumferential direction of the output shaft 12. 23B. With this configuration, the pair of magnetic poles 23 a and 23 b included in each of the magnetic pole groups 23 </ b> A and 23 </ b> B are disposed to face each other along the axial direction of the output shaft 12. Note that the edges of the yoke 22 constituting the pair of magnetic poles 23a and 23b are each configured to have a wedge-shaped longitudinal section, and the acute angle portion of the edges is the circumferential direction of the output shaft 12 of the yoke 22. It is comprised so that it may be located in the edge part side along.

  The permanent magnet 16 provided in the above-described movable element 10 is inserted and disposed between the split stators arranged so as to surround the output shaft 12 along the circumferential direction of the output shaft 12. More specifically, the permanent magnets 16 are disposed between the divided stators that are spaced apart along the circumferential direction of the output shaft 12, and the main surfaces of the permanent magnets 16 are adjacent to each other. Opposing to the magnetic pole groups 23A and 23B provided at the end of the split stator. The permanent magnet 16 and the magnetic pole groups 23A and 23B are configured to be non-contact by forming a predetermined clearance therebetween.

  3 and 4 are schematic diagrams for explaining the operation of the linear motor in the present embodiment. Next, with reference to these FIG. 3 and FIG. 4, it demonstrates in detail about operation | movement of 1 A of linear motors in this Embodiment. 3 and 4 show only two divided stators arranged along the circumferential direction of the output shaft 12 and three permanent magnets arranged so as to be adjacent to the two divided stators. FIG. In the following, the split stator located on the left side in the figure is referred to as “first split stator”, and the split stator located on the right side in the figure is referred to as “second split stator”.

  In order to operate the linear motor 1A in the present embodiment, an alternating current is applied to the coils 24 provided in each of the split stators using an alternating current applying means (not shown). Here, the alternating current supplied to the coil 24 included in the adjacent split stator is supplied so that magnetic flux is generated in different directions in the coil 24 included in the adjacent split stator. As a result, the magnetic circuits are formed in different directions on the yokes included in the adjacent split stators. More specifically, the states shown in FIGS. 3 and 4 are repeated during application of the alternating current.

  Specifically, in the state shown in FIG. 3, a current is applied in a predetermined direction to the coil 24 included in the first split stator so that the first yoke portion included in the first split stator serves as the first yoke portion. A magnetic flux is generated in the columnar portion 22a of the yoke 22 in the direction of the arrow B1 in the figure, and as a result, as shown in each of a pair of edges formed at both ends of the yoke 22 in the circumferential direction of the output shaft 12. The first magnetic pole group 23A and the second magnetic pole group 23B are generated. On the other hand, when a current in a predetermined direction is applied to the coil 24 included in the second split stator, the arrow C1 in the figure is applied to the columnar portion 22a of the yoke 22 as the second yoke portion included in the second split stator. A magnetic flux is generated in a direction (the C1 direction is opposite to the arrow B1 direction described above), and accordingly, a pair of edges formed at both ends of the yoke 22 in the circumferential direction of the output shaft 12 respectively. Thus, the first magnetic pole group 23A and the second magnetic pole group 23B are generated as shown in FIG.

  Here, when attention is paid to the first magnetic pole group 23A of the adjacent first divided stator, the second magnetic pole group 23B of the second divided stator, and the permanent magnet 16 positioned between them, the first magnetic pole group 23A includes them. One of the magnetic poles 23a and 23b and one of the magnetic poles 23a and 23b included in the second magnetic pole group 23B arranged to face the one magnetic pole are excited to have opposite polarities, and are arranged between them. In relation to the N pole 16a and the S pole 16b of the permanent magnet 16, thrust is generated in the permanent magnet 16 in the direction indicated by the arrow A1 direction in the figure. The direction of this thrust is the same in the adjacent permanent magnets 16 in the state shown in FIG. 3, and as a result, the mover 10 moves in the direction of the arrow A1 in the figure.

  On the other hand, in the state shown in FIG. 4 in which the direction of the current supplied to the coil 24 is reversed, the first divided stator is applied by applying a current in a predetermined direction to the coil 24 included in the first divided stator. A magnetic flux is generated in the direction of the arrow B2 in the figure in the columnar portion 22a of the yoke 22 as the first yoke portion included in the pair, and along with this, a pair formed at both ends in the circumferential direction of the output shaft 12 of the yoke 22 Polarity as shown in the figure is generated at each of the edges of the first and second magnetic pole groups 23A and 23B. On the other hand, when a current in a predetermined direction is applied to the coil 24 included in the second split stator, an arrow C2 in the figure is applied to the columnar portion 22a of the yoke 22 as the second yoke portion included in the second split stator. A magnetic flux is generated in a direction (the C2 direction is opposite to the arrow B2 direction described above), and accordingly, a pair of edges formed at both ends of the yoke 22 in the circumferential direction of the output shaft 12 respectively. Thus, the first magnetic pole group 23A and the second magnetic pole group 23B are generated as shown in FIG.

  Here, when attention is paid to the first magnetic pole group 23A of the adjacent first divided stator, the second magnetic pole group 23B of the second divided stator, and the permanent magnet 16 positioned between them, the first magnetic pole group 23A includes them. One of the magnetic poles 23a and 23b and one of the magnetic poles 23a and 23b included in the second magnetic pole group 23B arranged to face the one magnetic pole are excited to have opposite polarities, and are arranged between them. In relation to the N pole 16a and the S pole 16b of the permanent magnet 16, thrust is generated in the permanent magnet 16 in the direction indicated by the arrow A2 in the figure. The direction of this thrust is the same in the adjacent permanent magnet 16 in the state shown in FIG. 4, and as a result, the mover 10 moves in the direction of arrow A2 in the figure.

  The state shown in FIGS. 3 and 4 described above is repeatedly and alternately reproduced, so that the mover 10 reciprocates in the directions of arrows A1 and A2 shown in FIG.

  By using the linear motor 1A in the present embodiment described above, the two yokes of the inner yoke and the outer yoke arranged in the radial direction of the output shaft required in the conventional linear motor are Since only one yoke 22 disposed in the radial direction is required, the size of the apparatus in the radial direction can be greatly reduced. Further, with the linear motor 1A in the present embodiment, even when the thickness of the yoke 22 needs to be increased in order to prevent magnetic saturation, the direction in which the thickness should be increased matches the circumferential direction of the output shaft 12. Therefore, the size of the apparatus in the radial direction is not increased.

  In addition, by using the linear motor 1A in the present embodiment, each of the divided stators can be shared by parts having the same shape. Therefore, like the conventional linear motor, the inner yoke and the outer yoke 2 are used. Compared to a configuration that requires two yokes, the number of required parts is reduced, and the manufacturing cost can be kept low.

  In addition, since the linear motor 1A in the present embodiment makes it possible to use a so-called flat plate magnet as the permanent magnet 16, it is necessary to process the permanent magnet into an annular shape or an arc shape as in the past. In addition, the manufacturing cost can be suppressed.

  Furthermore, by using the linear motor 1A in the present embodiment, the main surface of the permanent magnet 16 that faces the magnetic pole groups 23A and 23B provided on the yoke 22 is supported in an exposed state. Therefore, the magnetic resistance can be kept low, and a high-performance linear motor can be obtained.

  FIG. 5 is a cross-sectional view showing a configuration of a linear motor according to a modification of the present embodiment. The cross section shown in FIG. 5 is a cross sectional view of the same portion as the cross section shown in FIG. Next, a configuration of a linear motor 1B according to a modification of the present embodiment will be described with reference to FIG.

  As shown in FIG. 5, a linear motor 1B according to a modification of the present embodiment includes a mover 10 and a stator 20, similar to the linear motor 1A in the present embodiment described above. In the linear motor 1B according to the present modification, the mover 10 mainly includes an output shaft 12 and eight permanent magnets 16 disposed on the outer periphery of the output shaft 12, and the stator 20 includes an output shaft. 12 is constituted by eight divided stators arranged along the circumferential direction of the output shaft 12 so as to surround the output shaft 12. Each of the eight split stators includes one yoke 22 and one coil 24. The configuration of each split stator is substantially the same as the configuration of the linear motor 1A in the above-described embodiment.

  Also in the linear motor 1B according to this modification, the permanent magnets 16 are arranged between the yokes 22 included in adjacent divided stators, and the arrangement direction thereof is the same as that of the linear motor 1A in the above-described embodiment. The N pole 16 a and the S pole 16 b are arranged in the circumferential direction of the output shaft 12.

  Even when the configuration as in the linear motor 1B according to the present modification as described above is adopted, the coils included in the adjacent split stators as in the case of the linear motor 1A in the present embodiment described above. The movable element 10 reciprocates in the axial direction of the output shaft 12 by energizing the coil 24 included in the adjacent split stator so that magnetic flux is generated in different directions. To move.

  Even in such a configuration, it is possible to obtain the same effect as that of the linear motor 1A in the present embodiment described above. Thus, the number of split stators and permanent magnets is not limited and can be changed as needed.

  Further, in the linear motor 1A in the above-described embodiment and the linear motor 1B according to the modification of the embodiment, the alternating current supplied to the coil 24 included in the adjacent divided stator is used as the adjacent divided stator. It is premised on that the coil 24 included is energized so that magnetic flux is generated in different directions. However, the linear current is configured so that an alternating current supplied to the coil 24 included in the adjacent split stator is supplied so that a magnetic flux is generated in the same direction in the coil 24 included in the adjacent split stator. The present invention can also be applied to a motor. In that case, the arrangement direction of the permanent magnets 16 is different from the linear motor 1A in the above-described embodiment and the linear motor 1B according to the modification of the embodiment, and the N pole 16a and the S pole 16b are output shafts. It is necessary to arrange them so that they are aligned in the 12 axial directions.

(Embodiment 2)
FIG. 6 is a schematic cross-sectional view showing the structure of the Stirling refrigerator in the second embodiment of the present invention. The Stirling refrigerator 100 according to the present embodiment includes the linear motor 1A according to the first embodiment as a piston driving unit. Therefore, in the following, description of the configuration of the linear motor 1A will not be repeated, and the structure of the Stirling refrigerator 100 will be mainly described.

  As shown in FIG. 6, the Stirling refrigerator 100 according to the present embodiment is a free piston type Stirling engine, and includes a casing 124 including a heat radiating unit 102 and a heat absorbing unit 103, and a cylinder 113 </ b> A assembled to the casing 124. 113B, piston 114 and displacer 115 reciprocating in cylinders 113A and 113B, displacer rod 115A, regenerator 116, working space 117 including compression space 117A and expansion space 117B, and piston drive means The linear motor 1 </ b> A, the piston spring 121, the displacer spring 122, and the back pressure space 123 are configured.

  The casing 124 defines the back pressure space 123. Various components including cylinders 113A and 113B, linear motor 1A, piston spring 121, and displacer spring 122 are assembled to casing 124. The casing 124 is filled with a working medium such as helium gas, hydrogen gas, or nitrogen gas.

  The cylinders 113A and 113B have a substantially cylindrical shape, and receive a piston 114 and a displacer 115 as a free piston in a reciprocating manner. In the cylinders 113A and 113B, the piston 114 and the displacer 115 are coaxially spaced apart, and the piston 114 and the displacer 115 partition the working space 117 into a compression space 117A and an expansion space 117B. More specifically, the working space 117 is a space located closer to the displacer 115 than the end surface of the piston 114 on the displacer 115 side. A compression space 117A is formed between the piston 114 and the displacer 115, and the displacer 115 and the heat absorbing portion are formed. An expansion space 117 </ b> B is formed between the first and second devices 103. The compression space 117 </ b> A is mainly surrounded by the heat dissipation unit 102, and the expansion space 117 </ b> B is mainly surrounded by the heat absorption unit 103.

  A regenerator 116 in which a film is wound with a predetermined gap is disposed between the compression space 117A and the expansion space 117B, and the compression space 117A and the expansion space are disposed via the regenerator 116. 117B communicates. Thereby, a closed circuit is configured in the Stirling refrigerator 100. The working medium enclosed in the closed circuit flows in accordance with the operation of the piston 114 and the displacer 115, whereby a reverse Stirling cycle is realized.

  A linear motor 1A is disposed in the back pressure space 123 located outside the cylinder 113A. The linear motor 1A includes the above-described mover 10 and stator 20. The output shaft 12 of the mover 10 is fixed to the piston 114 (or the piston 114 itself also serves as the output shaft). It is fixed to the casing 124 via the cylinder 113A. The linear motor 1A drives the piston 114 in the axial direction of the cylinder 113A (in the directions of arrows A1 and A2).

  One end of the piston 114 is connected to a piston spring 121 constituted by a plate spring or the like. The piston spring 121 functions as “elastic force applying means” for applying an elastic force to the piston 114. By applying an elastic force by the piston spring 121, the piston 114 can be reciprocated periodically and stably in the cylinder 113A. One end of the displacer 115 is connected to the displacer spring 122 via the displacer rod 115A. The displacer rod 115A is disposed through the piston 114, and the displacer spring 122 is configured by a leaf spring or the like.

  A back pressure space 123 surrounded by a casing 124 is disposed on the side opposite to the displacer 115 with respect to the piston 114. There is also a working medium in the back pressure space 123.

  A heat exchanger 118 and a heat exchanger 119 are provided on the inner peripheral surfaces of the heat dissipating unit 102 and the heat absorbing unit 103, respectively. The heat exchangers 118 and 119 perform heat exchange between the compression space 117 </ b> A and the expansion space 117 </ b> B and the heat dissipation unit 102 and the heat absorption unit 103, respectively.

  Next, the operation of the Stirling refrigerator 100 will be described in detail with reference to FIG.

  The Stirling refrigerator 100 uses a so-called reverse Stirling cycle to obtain a refrigeration effect. The piston 114 is driven by the linear motor 1A to make a sine motion. Due to the movement of the piston 114, the working medium in the compression space 117A exhibits a sinusoidal pressure change. The compressed working medium releases compression heat at the heat radiating portion 102, is pre-cooled when passing through the regenerator 116 provided outside the cylinder 113B, and flows into the expansion space 117B.

  The displacer 115 sine-moves with a constant phase difference in the same cycle as the piston 114 during steady operation, and the phase difference and amplitude are the spring constant of the displacer spring 122 and the compression space 117A and the expansion space 117B that change from moment to moment. This is determined by the pressure difference between the two, the mass of the displacer 115, the operating frequency, and the like. About this phase difference, it is generally said that about 90 degrees is the optimum condition.

  The working medium that has flowed into the expansion space 117B expands due to the sinusoidal movement of the displacer 115, whereby the temperature in the expansion space 117B decreases significantly. By transmitting the extremely low temperature (for example, about −50 ° C.) generated at this time to the inside of the refrigerator through the heat absorbing portion 103, a desired cooling effect can be obtained.

  Like the Stirling refrigerator 100 described above, the linear motor 1A having the configuration described in the above-described first embodiment is used as the driving means for the piston 114, so that the high-performance Stirling can be manufactured in a small size and at low cost. It can be a refrigerator.

  It should be noted that the above-described embodiments and modifications thereof disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a perspective view which shows the external appearance structure of the linear motor in Embodiment 1 of this invention. It is sectional drawing at the time of cut | disconnecting the linear motor in Embodiment 1 of this invention along the plane orthogonal to the said axial direction in the center position of an axial direction. It is a schematic diagram for demonstrating operation | movement of the linear motor in Embodiment 1 of this invention. It is a schematic diagram for demonstrating operation | movement of the linear motor in Embodiment 1 of this invention. It is sectional drawing which shows the structure of the linear motor which concerns on a modification. It is a schematic cross section which shows the structure of the Stirling refrigerator in Embodiment 2 of this invention.

Explanation of symbols

  1A, 1B linear motor, 10 mover, 12 output shaft, 14 mounting part, 16 permanent magnet, 16a N pole, 16b S pole, 20 stator, 22 yoke, 22a columnar part, 23A, 23B magnetic pole group, 23a, 23b Magnetic pole, 24 coils, 100 Stirling refrigerator, 102 heat radiating section, 103 heat absorbing section, 113A, 113B cylinder, 113A1 flange section, 114 piston, 115 displacer, 115A displacer rod, 116 regenerator, 117 working space, 117A compression space, 117B Expansion space, 118,119 heat exchanger, 121 piston spring, 122 displacer spring, 123 back pressure space, 124 casing.

Claims (6)

A mover including an output shaft and a permanent magnet;
A stator including a coil and a yoke,
A linear motor in which the stator is provided along the circumferential direction of the output shaft so as to surround the output shaft;
The stator has a first yoke part and a second yoke part that are spaced apart along the circumferential direction of the output shaft,
The first yoke portion includes a first magnetic pole group including a pair of magnetic poles excited in opposite polarities at a portion facing the second yoke portion,
The pair of magnetic poles included in the first magnetic pole group are arranged to face each other along the axial direction of the output shaft,
The second yoke part includes a second magnetic pole group including a pair of magnetic poles excited in the opposite polarity at a portion facing the first yoke part,
The pair of magnetic poles included in the second magnetic pole group are disposed to face each other along the axial direction of the output shaft,
The permanent magnet is a linear motor disposed between the first yoke portion and the second yoke portion and between the first magnetic pole group and the second magnetic pole group. The permanent magnet is arranged so that the N pole and the S pole are aligned along the circumferential direction of the output shaft,
One of the pair of magnetic poles included in the first magnetic pole group and one of the pair of magnetic poles included in the second magnetic pole group disposed opposite to the one magnetic pole group are excited to have opposite polarities. The linear motor according to claim 1, wherein the linear motor is configured. The stator is composed of a plurality of divided stators each including a coil and a yoke,
The linear motor according to claim 1, wherein the first yoke portion and the second yoke portion are configured by yokes included in each of a pair of adjacent divided stators. The mover has an attachment portion for fixing the permanent magnet to the output shaft,
The linear in any one of Claim 1 to 3 by which the surface in the circumferential direction of the said output shaft of the said permanent magnet is exposed because the said attaching part clamps the said permanent magnet in the axial direction of the said output shaft. motor.   The linear motor according to claim 1, wherein the permanent magnet has a flat plate shape.   A Stirling refrigerator comprising the linear motor according to claim 1 as a piston driving means.

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