JP2009177973A - Linear motor, and stirling engine and stirling engine mounted apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear motor whose manufacturing cost is reduced and to provide a stirling engine and a stirling engine mounted apparatus with the linear motor. <P>SOLUTION: The linear motor includes an outer yoke 181, an inner yoke 182 provided at the inside circumference side of the outer yoke 181, and a movable magnet part 183, which reciprocates in the axial direction between the outer yoke 181 and the inner yoke 182. The movable magnet part 183 includes first and second magnets 183A, 183B arranged side by side in the axial direction. The first and second magnets 183A, 183B are provided such that each pair of magnetic poles (N pole/S pole) is arranged side by side in the reverse order to each other in the radial direction. The axial length L1 of the first magnet 183A, the axial length L2 of the second magnet 183B, the axial length L of the outer yoke 181 and the inner yoke 182, and the magnitude S of the movable magnet part 183 satisfy the relation of L1≥S+L/2 and L2≥S+L/2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a linear motor, a Stirling engine, and a Stirling engine-equipped device, and more particularly to a linear motor that moves a movable magnet portion in an axial direction, and a Stirling engine and a Stirling engine-equipped device including the linear motor.

Conventionally, a linear motor for driving a piston is known.
For example, Japanese Patent Laid-Open No. 8-200212 (Patent Document 1) discloses that an electric element in a linear compressor includes a stator and a vibrator that is reciprocated by the action of a magnetic field generated by the stator and a permanent magnet. The composition is described. Here, in the vibrator, permanent magnets having different polarities are arranged in parallel in the moving direction of the piston.
JP-A-8-200212

  In order to constantly reciprocate the vibrator as described above, it is necessary to apply a restoring force corresponding to the displacement amount to the vibrator.

  In the electric element described in Patent Document 1, a restoring force is applied to the vibrator by spring members provided on both sides of the permanent magnet. By providing such a spring member, the number of parts increases, and as a result, the manufacturing cost of the electric element increases.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a linear motor with reduced manufacturing costs, a Stirling engine equipped with the linear motor, and a Stirling engine-equipped device. It is in.

  A linear motor according to the present invention is provided on a ring-shaped outer yoke, a coil wound around the outer yoke, and an inner peripheral side of the outer yoke, and has the same axial length as the outer yoke and the axial direction of the outer yoke. And an inner yoke provided with the same position, and a movable magnet portion that reciprocates in the axial direction between the outer yoke and the inner yoke. The movable magnet unit includes first and second magnets arranged in the axial direction. The first and second magnets are provided such that a pair of magnetic poles are arranged in the radial direction in the opposite order, and the movable magnet unit has an amplitude. When located at the center, the boundary between the first and second magnets coincides with the axial center of the outer yoke and the inner yoke, the axial length L1 of the first magnet, the axial length L2 of the second magnet, and the outer The axial length L of the yoke and inner yoke and the amplitude S of the movable magnet portion satisfy the relationship of L1 ≧ S + L / 2 and L2 ≧ S + L / 2.

  According to the above configuration, since the restoring force by the magnetic force having the magnitude corresponding to the displacement amount of the movable magnet portion can be applied to the movable magnet portion over the entire movable range of the movable magnet portion, the restoring force is generated. The spring member can be omitted. As a result, the manufacturing cost of the linear motor is reduced.

  In one embodiment, in the linear motor, the outer yoke and the inner yoke are formed by laminating a plurality of electromagnetic steel plates in the axial direction.

  In one embodiment, in the linear motor, the axial length L1 of the first magnet and the axial length L2 of the second magnet satisfy the relationship L1 = L2.

  In one embodiment, in the linear motor, the axial length L1 of the first magnet, the axial length L2 of the second magnet, the axial length L of the outer yoke and the inner yoke, and the amplitude S of the movable magnet portion are L1. = L2 = 2S = L is satisfied.

  In one embodiment, in the linear motor, the outer yoke has a tooth portion formed so as to protrude toward the inner yoke on the inner peripheral surface of the outer yoke, and the coil is wound around the tooth portion. Is done.

  A Stirling engine according to the present invention has a back pressure space, a working space including a compression space and an expansion space, a casing in which a working medium is enclosed, a cylinder assembled in the casing, a back pressure space, and an operation. Is provided between the piston, which reciprocates in the cylinder and applies pressure fluctuations to the working medium in the working space, and between the compression space and the expansion space. A displacer that reciprocates and the linear motor described above are provided, and the piston is driven by the linear motor. A Stirling engine-equipped device according to the present invention includes the Stirling engine described above.

  As a result, a Stirling engine and a Stirling engine-equipped device with reduced manufacturing costs can be obtained.

  According to the present invention, since the spring member that applies a restoring force to the piston of the linear motor can be omitted, the manufacturing cost of the linear motor can be reduced.

  Embodiments of the present invention will be described below. Note that the same or corresponding parts are denoted by the same reference numerals, and the description thereof may 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.

(Description of Stirling refrigerator)
FIG. 1 is a piping system diagram of a Stirling refrigerator as a “Stirling engine-equipped device” according to one embodiment of the present invention.

  Referring to FIG. 1, a Stirling refrigerator 1000 includes a Stirling refrigerator 100 (Stirling engine) having a low temperature part and a high temperature part, and a low temperature side circulation circuit 200 that is a refrigerant circuit for transmitting the cold heat of the low temperature part. The first high temperature side circulation circuit 300 and the second high temperature side circulation circuit 400, which are refrigerant circuits for transmitting the heat of the high temperature part, are configured.

  The low temperature side circulation circuit 200 includes a low temperature side evaporator 210, refrigerant pipes 220 and 230, a low temperature side condenser 240 attached to a low temperature part of the Stirling refrigerator 100, and a fan 250. The low temperature side circulation circuit 200 performs heat exchange between the air in the refrigerator and the low temperature part of the Stirling refrigerator 100.

  In the low temperature side circulation circuit 200, carbon dioxide, hydrocarbons and the like are sealed as a refrigerant. The refrigerant condensed in the low temperature side condenser 240 flows through the refrigerant pipe 230 (low temperature side conduit) and reaches the low temperature side evaporator 210. Heat exchange is performed by evaporating the refrigerant in the low temperature side evaporator 210. In order to promote this heat exchange, a fan 250 is provided in the vicinity of the low temperature side evaporator 210 to generate an air flow. After the heat exchange, the gasified refrigerant returns to the low temperature side condenser 240 via the refrigerant pipe 220 (low temperature side return pipe). The refrigerant that has flowed into the low-temperature side condenser 240 and condensed flows into the refrigerant pipe 230.

  In the low-temperature side circulation circuit 200, the low-temperature side evaporator 200 can transmit cold heat generated in the low-temperature part of the Stirling refrigerator 100 using the natural circulation caused by the evaporation and condensation of the refrigerant. 210 is disposed below the low-temperature side condenser 240. Further, the pressure in the circulation circuit system is adjusted in order to adjust the boiling point of the refrigerant.

  The first high temperature side circulation circuit 300 includes a high temperature side condenser 310, refrigerant pipes 320 and 330, and a high temperature side evaporator 340. The first high temperature side circulation circuit 300 cools the high temperature part of the Stirling refrigerator 100.

Water (H ₂ O) or the like is sealed in the first high temperature side circulation circuit 300 as a refrigerant. The refrigerant evaporated in the high temperature side evaporator 340 flows through the refrigerant pipe 330 (high temperature side conduit) and reaches the high temperature side condenser 310. The refrigerant is condensed by heat exchange with the outside air in the high temperature side condenser 310. In order to promote this heat exchange, a fan 350 that generates an air flow in the vicinity of the high-temperature side condenser 310 is provided. The condensed refrigerant flows through the refrigerant pipe 320 (high temperature side return pipe) and returns to the high temperature side evaporator 340. In the first high temperature side circulation circuit 300, the high temperature side is used so that the heat generated in the high temperature portion of the Stirling refrigerator 100 can be transmitted using the natural circulation caused by the evaporation and condensation of the refrigerant. A condenser 310 is disposed above the high temperature side evaporator 340. Further, the pressure in the circulation circuit system is adjusted in order to adjust the boiling point of the refrigerant.

  The second high temperature side circulation circuit 400 includes refrigerant pipes 410, 430, 450, a circulation pump 420, and a dew prevention pipe 440. The second high temperature side circulation circuit 400 transmits the heat of the high temperature part of the Stirling refrigerator 100 to the dew condensation prevention pipe 440.

  The refrigerant pipe 410 is connected to the lower part of the high temperature side evaporator 340. Liquid phase refrigerant flows into the refrigerant pipe 410 from the high temperature side evaporator 340. The refrigerant that has flowed into the refrigerant pipe 410 reaches a circulation pump 420 provided below the Stirling refrigerator 100. The refrigerant discharged from the circulation pump 420 is sent to the dew prevention pipe 440 via the refrigerant pipe 430. The refrigerant flowing in the dew prevention pipe 440 is kept at a relatively high temperature by the heat given from the high temperature part of the Stirling refrigerator 100. Therefore, by providing the dew prevention pipe 440 on the front surface of the refrigerator, it is possible to suppress dew generation at the door portion and the like. The refrigerant that has flowed through the dew condensation prevention pipe 440 returns to the high temperature side evaporator 340 through the refrigerant pipe 450. Thus, in the 2nd high temperature side circulation circuit 400, the forced circulation by the circulation pump 420 is performed.

  When the Stirling refrigerator 100 is operated, the heat generated in the high temperature part of the refrigerator 100 is heat-exchanged with air via the high temperature side condenser 310. On the other hand, the cold generated in the low temperature part of the Stirling refrigerator 100 is heat exchanged with the air in the refrigerator through the low temperature side evaporator 210. The warmed airflow from the inside of the refrigerator is sent again to the vicinity of the low temperature side evaporator 210 and repeatedly cooled.

  In the example of FIG. 1, the Stirling refrigerator 100 is installed so that the high temperature portion and the low temperature portion in the Stirling refrigerator 100 are aligned in the horizontal direction (that is, horizontally). More specifically, the Stirling refrigeration is performed so that the high temperature part of the Stirling refrigerator 100 is positioned above the low temperature part of the Stirling refrigerator 100 so that the low temperature part is aligned in the vertical direction (that is, vertically). Machine 100 may be installed.

(Description of Stirling refrigerator)
FIG. 2 is a side sectional view showing a Stirling refrigerator as a “Stirling engine” according to one embodiment of the present invention. Referring to FIG. 2, Stirling refrigerator 100 according to the present embodiment is a free piston type Stirling engine, and includes casing 110 including high temperature portion 111 and low temperature portion 112, and assembled to casing 110. Cylinder 120 (121, 122), piston 130 and displacer 140 reciprocating in cylinder 121, 122, working space 150 including compression space 151 and expansion space 152, regenerator 160, heat exchanger 161, 162, a back pressure space 170, a linear motor 180 as piston driving means, and a displacer spring 190.

  The casing 110 defines a back pressure space 170. Various parts including the cylinder 120 and the linear motor 180 are assembled to the casing 110. The casing 110 is filled with a working medium such as helium gas, hydrogen gas, or nitrogen gas.

  The cylinders 121 and 122 have a substantially cylindrical shape, and receive therein a piston 130 and a displacer 140 as a free piston so as to be able to reciprocate. In the cylinder 120, the piston 130 and the displacer 140 are arranged coaxially with a space therebetween, and the piston 130 and the displacer 140 divide the working space 150 into a compression space 151 and an expansion space 152. More specifically, the working space 150 is a space located closer to the displacer 140 than the end face of the piston 130 on the displacer 140 side. A compression space 151 is formed between the piston 130 and the displacer 140, and the displacer 140 and the low temperature portion An expansion space 152 is formed between the two and 112. The compression space 151 is mainly surrounded by the high temperature part 111, and the expansion space 152 is mainly surrounded by the low temperature part 112.

  A rod member 122A is attached to the cylinder 122, and the rod member 122A is inserted into the displacer 140 so as to reach the inner space of the displacer 140. A displacer spring 190 including a coil spring is provided between the rod member 122 </ b> A reaching the inner space of the displacer 140 and the inner surface of the displacer 140. The displacer spring 190 imparts an elastic force to the displacer 140. By applying an elastic force by the displacer spring 190, the displacer 140 can be reciprocated in the cylinder 122 more stably and periodically.

  Between the compression space 151 and the expansion space 152, a regenerator 160 in which a film is wound with a predetermined gap is disposed, and the compression space 151 and the expansion space are interposed via the regenerator 160. 152 communicates. Thereby, a closed circuit is configured in the Stirling refrigerator 100. The working medium sealed in the closed circuit flows in accordance with the operations of the piston 130 and the displacer 140, whereby a reverse Stirling cycle is realized.

  On the inner peripheral surfaces of the high temperature part 111 and the low temperature part 112, a heat exchanger 161 and a heat exchanger 162 are provided, respectively. The heat exchangers 161 and 162 perform heat exchange between the compression space 151 and the expansion space 152 and the high temperature portion 111 and the low temperature portion 112, respectively.

A back pressure space 170 surrounded by the casing 110 is disposed on the opposite side of the piston 130 from the displacer 140. There is also a working medium in the back pressure space 170.

  A linear motor 180 is disposed in a portion of the back pressure space 170 located outside the cylinder 120. The linear motor 180 includes an outer yoke 181 around which a coil is wound, an inner yoke 182, and a movable magnet unit 183. The linear motor 180 drives the piston 130 in the axial direction of the cylinder 121.

Next, the operation of the Stirling refrigerator 100 will be described.
This refrigerator obtains a refrigeration effect using a so-called reverse Stirling cycle. The piston 130 is driven by a linear motor 180 to move sinusoidally. Due to the movement of the piston 130, the working medium in the compression space 151 exhibits a sinusoidal pressure change. The compressed working medium releases compression heat at the high temperature portion 111, is precooled when passing through the regenerator 160 provided outside the cylinder 120, and flows into the expansion space 152.

  The displacer 140 performs a sinusoidal motion with a constant phase difference in the same cycle as the piston 130 during steady operation, and the phase difference and amplitude change between the spring constant of the displacer spring 190 and the compression space 151 and the expansion space 152 that change from moment to moment. It is determined by the pressure difference, the mass of the displacer 140, the operating frequency, and the like. About this phase difference, it is generally said that the optimum condition is about 90 degrees.

  The working medium that has flowed into the expansion space 152 expands due to the sinusoidal movement of the displacer 140, whereby the temperature in the expansion space 152 is significantly reduced. By transmitting the extremely low temperature (for example, about −50 ° C.) generated at this time into the refrigerator through the low temperature portion 112, a desired cooling effect can be obtained.

  FIG. 3 is a side sectional view showing a modified example of the Stirling refrigerator 100. Referring to FIG. 3, in the Stirling refrigerator 100 according to this modification, a displacer rod 140 </ b> A protruding from the axial end surface of the displacer 140 on the compression space 151 side is provided, and the displacer rod 140 </ b> A is formed in the center hole of the piston 130. It extends through the back pressure space 170 and is connected to a displacer spring 190 provided in the back pressure space 170. The Stirling refrigerator 100 having such a structure can also be operated in the same manner as the Stirling refrigerator 100 shown in FIG.

  The Stirling refrigerator 100 shown in FIGS. 2 and 3 is characterized in that a displacer spring 190 for applying an elastic force to the displacer 140 is provided, while a piston spring for applying an elastic force to the piston 130 is not provided. As described above, the characteristic feature of the linear motor 180 is that the piston 130 can be stably reciprocated in the cylinder 121 in spite of the absence of the piston spring. Because. Below, the structure of the linear motor 180 which can stabilize the reciprocation of the piston 130 is demonstrated.

(Description of linear motor structure)
Here, the structure of the linear motor according to the present embodiment will be described with reference to FIGS. 4 is a top view showing an outer yoke and an inner yoke in the linear motor according to the present embodiment, and FIG. 5 is a cross-sectional view taken along line VV in FIG. 6 and 7 are a top view and a longitudinal sectional view showing the linear motor according to the present embodiment, respectively.

  4 to 7, the linear motor according to the present embodiment includes a ring-shaped outer yoke 181, an inner yoke 182 provided on the inner peripheral side of outer yoke 181, outer yoke 181 and inner yoke. And a movable magnet portion 183 that reciprocates in the axial direction between the movable portion 182 and the portion 182.

  As shown in FIGS. 4 and 6, the outer yoke 181 has a tooth portion 181T, and a coil 181A is wound around the tooth portion 181T. As shown in FIGS. 5 and 7, the inner yoke 182 has the same axial length (L) as the outer yoke 181, and is provided in alignment with the outer yoke 181 in the axial direction.

  Referring to FIG. 4, teeth portion 181 </ b> T is provided so as to protrude radially inward from the inner peripheral surface of outer yoke 181. A plurality of teeth 181T are provided so as to be arranged at equal intervals in the circumferential direction of the outer yoke 181.

  Referring to FIG. 5, outer yoke 181 and inner yoke 182 are formed by laminating a plurality of electromagnetic steel plates in the axial direction. The thickness of the electrical steel sheet that constitutes the outer yoke 181 is the same as the thickness of the electrical steel sheet that constitutes the inner yoke 182. By doing in this way, since the electromagnetic steel plate which comprises the outer yoke 181 and the electromagnetic steel plate which comprises the inner yoke 182 can be produced from one electromagnetic steel plate by one press process, manufacture of a linear motor Cost can be reduced.

  Referring to FIG. 7, movable magnet unit 183 includes a first magnet 183A, a second magnet 183B, and a holder 183C that holds first and second magnets 183A and 183B. The first and second magnets 183A and 183B arranged in the axial direction are provided such that a pair of magnetic poles (N pole / S pole) are arranged in the radial direction in the opposite order. More specifically, the first magnet 183A is provided so that the N pole is located radially inward and the S pole is located radially outside, whereas the second magnet 183B has the S pole radially inward. , N poles are provided so as to be located radially outside. FIG. 7 shows a state where the movable magnet unit 183 is located at the amplitude center. The boundary between the first and second magnets 183A and 183B coincides with the axial center of the outer yoke 181 and the inner yoke 182 in the state of FIG. The holder 183C is connected to the piston 130. The piston 130 reciprocates in the vertical direction in FIG. 7 together with the movable magnet portion 183.

  In a state where the movable magnet portion 183 is slightly shifted upward from the state of FIG. 7, a current in a predetermined direction is supplied to the coil 181A so that a magnetic flux flows from the outer yoke 181 to the inner yoke 182 (that is, the outer yoke 181). N pole is formed on the inner yoke 182 and S pole is formed on the inner yoke 182), the center of the first magnet 183A is brought closer to the axial center of the outer yoke 181 and the inner yoke 182 while the center of the second magnet 183B is A magnetic force acting on the movable magnet portion 183 so as to keep the outer yoke 181 and the inner yoke 182 away from the axial center. That is, when the movable magnet unit 183 moves from the amplitude center to the upper side in FIG. 7, a downward restoring force that attempts to return the movable magnet unit 183 to the amplitude center acts on the movable magnet unit 183. The magnetic force increases in proportion to the amount of movement of the movable magnet unit 183 upward in FIG. That is, when the movable magnet unit 183 moves upward from the state of FIG. 7, a restoring force corresponding to the displacement amount of the movable magnet unit 183 acts on the movable magnet unit 183. In addition, even when the movable magnet portion 183 moves downward from the state shown in FIG. 7, a current that forms an S pole on the outer yoke 181 and an N pole on the inner yoke 182 is caused to flow through the coil 181A. Similarly to the above, a restoring force corresponding to the amount of displacement of the movable magnet portion 183 can be applied to the movable magnet portion 183.

  In the present embodiment, the axial length L1 of the first magnet 183A, the axial length L2 of the second magnet 183B, the axial length L of the outer yoke 181 and the inner yoke 182 and the amplitude S of the movable magnet portion 183 are L1. = L2 = 2S = L is set to satisfy the relationship. By doing in this way, the restoring force according to the displacement amount of the movable magnet part 183 can be made to act on this movable magnet part 183 in the whole movable range of the movable magnet part 183. As a result, in the linear motor according to the present embodiment, the displacement amount of the movable magnet portion 183 (= displacement amount of the piston 130) and the restoring force acting on the movable magnet portion 183 (= restoring force acting on the piston 130). The relationship is as shown in FIG.

FIG. 10 is a longitudinal sectional view showing a linear motor according to a comparative example. In the comparative example shown in FIG. 10, the second magnet portion 183B is not provided as in the present embodiment, and the N pole (radially inner side) and the S pole (radially outer side) are opposed to each other in the radial direction. The movable magnet portion 183 is configured by the provided first magnet 183A and the holder 183C that holds the first magnet 183A. The ring-shaped outer yoke 181 has a C-shaped cross section. The coil 181A is wound around the outer yoke 181 so that N poles / S poles can be formed at salient pole portions located at both ends of the C-shape of the outer yoke 181. In the linear motor shown in FIG. By switching the direction of the current flowing through 181A, the N pole / S pole are switched, and a magnetic force in the vertical direction is applied to the movable magnet portion 183 to reciprocate the piston 130 together with the movable magnet portion 183. More specifically, when an N pole is formed on the upper salient pole portion in FIG. 10 and an S pole is formed on the lower salient pole portion, an upward magnetic force acts on the first magnet 183A to move the first magnet 183A. The magnet part 183 and the piston 130 move upward. Conversely, when an N pole is formed in the lower salient pole portion in FIG. 10 and an S pole is formed in the upper salient pole portion, a downward magnetic force acts on the first magnet 183A, and the movable magnet portion 183 is formed. And the piston 130 moves downward.

  In the comparative example of FIG. 10, although the movable magnet unit 183 and the piston 130 are reciprocated using magnetic force, the amplitude increases in proportion to the displacement amount of the movable magnet unit 183 and the amplitude of the movable magnet unit 183 is increased. A magnetic force that returns to the center cannot be generated. Therefore, in the comparative example of FIG. 10, the piston spring 130 </ b> A is attached to the movable magnet unit 183 and the piston 130 in order to make the movable magnet unit 183 and the piston 130 reciprocate constantly. The piston spring 130A is configured by, for example, a leaf spring. By providing such a piston spring 130A, the number of parts of the linear motor 180 increases, and as a result, the manufacturing cost of the linear motor 180 increases.

  On the other hand, in the linear motor according to the present embodiment, as described above, the restoring force by the magnetic force according to the displacement amount of the movable magnet unit 183 is applied to the movable magnet unit 183 over the entire movable range of the movable magnet unit 183. Since it can be made to act, the piston spring 130A shown in FIG. 10 can be omitted. As a result, the manufacturing cost of the linear motor 180 is reduced.

  Further, as in this embodiment, omitting the piston spring may cause a problem that the piston 130 can be held so as not to move unexpectedly when electricity is not conducted to the coil 181A. When no current flows through the coil 181A, the first and second magnets 183A and 183B are attracted to and attached to the outer yoke 181 or the inner yoke 182 by the magnetic force, so that the piston 130 moves unexpectedly. Is prevented.

  Further, the direction of the magnetic flux during operation differs between the linear motor according to the present embodiment and the linear motor according to the comparative example shown in FIG. In the linear motor according to the present embodiment, as described above, eddy current loss can be reduced by stacking a plurality of electromagnetic steel plates in the axial direction. As a result, the eddy current loss during operation of the linear motor according to the present embodiment is approximately the same as that of the linear motor according to the comparative example shown in FIG.

  In the present embodiment, the axial length L1 of the first magnet, the axial length L2 of the second magnet, the axial length L of the outer yoke and the inner yoke, and the amplitude S of the movable magnet portion are L1 = L2 = Although the example satisfying the relationship of 2S = L has been described, the relationship of L1, L2, L, S is not limited to this, and the relationship of L1 ≧ S + L / 2 and even L2 ≧ S + L / 2 can be satisfied. In the same manner as described above, a restoring force corresponding to the amount of displacement of the movable magnet unit 183 can be applied to the movable magnet unit 183 over the entire movable range of the movable magnet unit 183.

  In the present embodiment, the example in which the tooth portion 181T is provided on the inner peripheral surface of the outer yoke 181 has been described, but the form of the outer yoke 181 is not limited to this. For example, as the outer yoke 181, as shown in FIG. 9, a hole portion 181 </ b> B extending in the axial direction and a bridge portion 181 </ b> C that partitions the hole portion 181 </ b> B are formed, and a coil is wound around the bridge portion 181 </ b> C. Is also possible.

  Although the embodiments of the present invention have been described above, the embodiments disclosed this time should be considered as illustrative in all points and not restrictive. The 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 piping system diagram of a Stirling cooler as a Stirling engine mounted device according to one embodiment of the present invention. 1 is a side sectional view showing a Stirling refrigerator as a Stirling engine according to one embodiment of the present invention. It is a sectional side view which shows the modification of the Stirling refrigerator as a Stirling engine which concerns on one embodiment of this invention. It is a top view which shows the outer yoke and inner yoke in the linear motor which concerns on one embodiment of this invention. It is VV sectional drawing in FIG. It is a top view which shows the linear motor which concerns on one embodiment of this invention. It is a longitudinal section showing a linear motor concerning one embodiment of the present invention. It is a figure which shows the relationship between the displacement amount of the piston in the linear motor which concerns on one embodiment of this invention, and the restoring force which acts on this piston. It is a top view which shows the modification of the outer yoke in the linear motor which concerns on one embodiment of this invention. It is a longitudinal cross-sectional view which shows the linear motor which concerns on a comparative example.

Explanation of symbols

  100 Stirling refrigerator, 110 casing, 111 high temperature part, 112 low temperature part, 120, 121, 122 cylinder, 122A rod member, 130 piston, 130A piston spring, 140 displacer, 140A displacer rod, 150 working space, 151 compression space, 152 Expansion space, 160 regenerator, 161, 162 heat exchanger, 170 back pressure space, 180 linear motor, 181 outer yoke, 181A coil, 181B hole, 181C bridge, 181T teeth, 182 inner yoke, 183 movable magnet , 183A first magnet, 183B second magnet, 183C holder, 190 displacer spring, 200 low temperature side circulation circuit, 210 low temperature side evaporator, 220, 230 refrigerant piping, 40 Low temperature side condenser, 250 fan, 300 First high temperature side circulation circuit, 310 High temperature side condenser, 320, 330 Refrigerant piping, 340 High temperature side evaporator, 350 fan, 400 Second high temperature side circulation circuit, 410, 430, 450 refrigerant piping, 420 circulation pump, 440 anti-condensation pipe, 1000 Stirling cooler.

Claims (7)

A ring-shaped outer yoke;
A coil wound around the outer yoke;
An inner yoke that is provided on the inner peripheral side of the outer yoke, has the same axial length as the outer yoke, and is aligned with the axial position of the outer yoke;
A movable magnet portion reciprocating in the axial direction between the outer yoke and the inner yoke;
The movable magnet portion includes first and second magnets arranged in the axial direction,
The first and second magnets are provided such that a pair of magnetic poles are arranged in the radial direction in the opposite order,
When the movable magnet portion is located at the amplitude center, the boundary between the first and second magnets coincides with the axial center of the outer yoke and the inner yoke,
The axial length L1 of the first magnet, the axial length L2 of the second magnet, the axial length L of the outer yoke and the inner yoke, and the amplitude S of the movable magnet portion are:
A linear motor that satisfies the relationship of L1 ≧ S + L / 2 and L2 ≧ S + L / 2.   The linear motor according to claim 1, wherein the outer yoke and the inner yoke are formed by laminating a plurality of electromagnetic steel plates in the axial direction. The axial length L1 of the first magnet and the axial length L2 of the second magnet are:
The linear motor according to claim 1, wherein the linear motor satisfies a relationship of L1 = L2. The axial length L1 of the first magnet, the axial length L2 of the second magnet, the axial length L of the outer yoke and the inner yoke, and the amplitude S of the movable magnet portion are:
The linear motor according to claim 1, wherein the linear motor satisfies a relationship of L1 = L2 = 2S = L. The outer yoke has a teeth portion formed so as to protrude toward the inner yoke on the inner peripheral surface of the outer yoke,
The linear motor according to claim 1, wherein the coil is wound around the teeth portion. A casing having a back pressure space and a working space including a compression space and an expansion space, and enclosing the working medium;
A cylinder assembled in the casing;
A piston that is provided between the back pressure space and the working space, and reciprocates in the cylinder to give pressure fluctuation to the working medium in the working space;
A displacer that is provided between the compression space and the expansion space and reciprocates in the cylinder by pressure fluctuations by the piston;
A linear motor according to any one of claims 1 to 5,
A Stirling engine that drives the piston by the linear motor.   A Stirling engine-equipped device comprising the Stirling engine according to claim 6.

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