JP2010200522A - Reciprocation driving mechanism, and cold storage type refrigerator using the reciprocation driving mechanism and compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and light-weighted reciprocation driving mechanism which obtains high efficiency by reducing an iron loss of a linear motor to freely reciprocate a piston inserted into a cylinder, to provide a compact and light-weighted cold storage type refrigerator using the reciprocation driving mechanism, which obtains high efficiency, and to provide a compressor. <P>SOLUTION: The reciprocation driving mechanism is constituted of a moving member 30 and a stator 21, and the moving member 30 includes: permanent magnets 32, 34 formed by magnetizing an outer peripheral surface to an N-pole and an S-pole in the radial direction, respectively; the permanent magnet 33 arranged in an axial gap between the permanent magnets 32 and 34, and magnetized in the direction of the permanent magnet 32 from the permanent magnet 34; and a piston 36 inserted into the cylinder 40 and coupled with the moving member 30. A stator 21 is arranged on the outer peripheral side of the permanent magnets 32, 34 with a predetermined distance, and includes an outer yoke 25 having a pair of magnetic pole pieces 22a, 23a and a pair of magnetic pole pieces 23b, 24a which face each other, respectively, with a predetermined distance in the axial direction, and arranged with coils 26, 27. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a reciprocating drive mechanism for freely reciprocating a piston inserted in a cylinder, a regenerative refrigerator and a compressor such as a Stirling refrigerator or a Stirling pulse tube refrigerator using the reciprocating drive mechanism. .

  As a regenerative refrigerator using a conventional reciprocating drive mechanism and a reciprocating drive mechanism, an outer yoke, and an inner yoke formed by molding soft magnetic iron powder disposed facing the inner side of the outer yoke, An electromagnetic actuator having a permanent magnet that is disposed between a coil portion provided on the outer yoke and the outer yoke and reciprocates in accordance with a change in magnetic flux generated by the coil portion, and a mover that supports the permanent magnet ( In some reciprocating drive mechanisms, an inner yoke and an outer yoke are provided with notched portions for preventing the generation of eddy currents. A Stirling engine is disclosed that includes the electromagnetic actuator, a piston connected to the mover, a cylinder that houses the piston, and a displacer that reciprocates with a phase difference from the piston (for example, a patent). Reference 1).

  Further, a reciprocating member provided with a movable yoke formed of a material having magnetic conductivity on the outer peripheral surface of a cylindrical holder and a permanent magnet magnetized in the radial direction on the outer peripheral surface of the movable yoke, and a permanent magnet An electromagnetic reciprocating mechanism (reciprocating drive mechanism) is constituted by a stator core provided close to the outer peripheral surface side and an electromagnetic coil that excites the stator core. Discloses a Stirling refrigerator that reciprocates a piston (see, for example, Patent Document 2).

JP 2005-20983 A JP 2004-180377 A

  However, according to Patent Document 1, generation of eddy current can be suppressed by providing a notch in the inner yoke, but the outer diameter of the inner yoke is increased in order to compensate for the decrease in the cross-sectional area of magnetic flux passing due to the notch. ing. For this reason, there is a problem that the electromagnetic actuator becomes larger and the Stirling engine (Stirling refrigerator) becomes larger. Further, there are gaps of two diameters, a gap on the outer diameter side of the permanent magnet (a gap between the outer yoke and the permanent magnet) and a gap on the inner diameter side of the permanent magnet (a gap with the inner yoke permanent magnet). Since these gaps (magnetic gaps) become magnetic resistances, there is a problem that the efficiency of the electromagnetic actuator is lowered, and accordingly, the efficiency of the Stirling engine is also lowered.

  According to Patent Document 2, the alternating magnetic flux generated by the electromagnetic coil passes through the magnet and flows to the movable yoke. Due to this alternating magnetic flux, eddy currents are generated in the movable yoke, the iron loss increases, and the efficiency of the electromagnetic reciprocation mechanism decreases, and the efficiency of the Stirling engine also decreases accordingly.

  The present invention has been made in view of the above problems, and by reducing the iron loss of a linear motor that freely reciprocates a piston inserted in a cylinder, a highly efficient, small and light reciprocating drive mechanism, and An object of the present invention is to provide a high-efficiency, small and light-weight regenerative refrigerator and compressor using the reciprocating drive mechanism.

  In order to solve the above problem, the invention described in claim 1 is arranged such that the first permanent magnet magnetized in the radial direction on the outer peripheral surface N and the first permanent magnet are arranged coaxially with a predetermined interval in the axial direction. The second permanent magnet magnetized in the opposite direction to the magnetization direction of the first permanent magnet, and the magnetization direction of the first permanent magnet and the magnetization direction of the second permanent magnet disposed in the gap between the first permanent magnet and the second permanent magnet A pair of movers provided with a third permanent magnet magnetized in a direction perpendicular to the first permanent magnet, and a pair of surfaces arranged at a predetermined distance on the outer peripheral side of the first permanent magnet and facing each other with a predetermined distance in the axial direction An outer yoke having a first magnetic pole piece and a pair of second magnetic pole pieces arranged at a predetermined distance on the outer peripheral side of the second permanent magnet and facing each other with a predetermined distance in the axial direction; The coil is arranged in the slot formed in Comprising a stator, a piston coupled to the armature, and a movable reciprocally inserted the cylinder in the axial direction of the piston.

  In the invention according to claim 2, a plurality of third permanent magnets adjacent to the first permanent magnet and the second permanent magnet are provided.

  According to a third aspect of the present invention, the first permanent magnet, the second permanent magnet, and the third permanent magnet are provided with a holding member made of a magnetic material on the inner peripheral surface.

  According to a fourth aspect of the present invention, there is provided a compression chamber formed of a piston and a cylinder for compressing the working gas, a radiator for radiating the compression heat of the working gas, a regenerator for exchanging heat with the working gas, and an operation A heat absorber that absorbs gas and an expansion chamber in which the working gas expands are provided.

  In the invention according to claim 5, the regenerative refrigerator is a Stirling refrigerator in which an expansion chamber is formed by an expansion side cylinder and an expansion side piston inserted into the expansion side cylinder so as to be able to reciprocate, or a pulse One of the Stirling type pulse tube refrigerators having a tube and phase adjusting means communicating with the high temperature side of the pulse tube and having an expansion chamber formed on the low temperature side of the pulse tube.

  According to a sixth aspect of the present invention, there is provided a compression chamber formed of a piston and a cylinder for compressing the working gas, a suction valve connected to the compression chamber and sucking the working fluid into the compression chamber, and a suction chamber connected to the compression chamber. A discharge valve that compresses the discharged working gas and discharges it from the compression chamber.

  According to the first aspect of the present invention, the mover is magnetized in a direction opposite to the magnetization direction of the first permanent magnet, the first permanent magnet having the radial direction and the outer peripheral surface magnetized to the N pole, and the first permanent magnet and the predetermined direction. The second permanent magnets are arranged coaxially with an interval of, and are magnetized in a direction perpendicular to the magnetization direction of the first permanent magnet and the magnetization direction of the second permanent magnet, and the gap between the first permanent magnet and the second permanent magnet A third permanent magnet is provided. As a result, when alternating current (current changing direction) is applied to the coils arranged in the slots of the stator, the magnetic flux fluctuates in a certain direction flowing from the second permanent magnet to the first permanent magnet through the third permanent magnet. (Magnetic flux with alternating component added to DC component) always exists. The amplitude and the maximum magnetic flux amount of the fluctuation magnetic flux in a certain direction are the same as the amplitude of the alternating magnetic flux (the magnetic flux in which the direction of the magnetic flux changes) of the electromagnetic actuator (reciprocating drive mechanism) according to the conventional technology under the same magnetic thrust. Compared to The iron loss of the first, second and third permanent magnets is reduced by reducing the amplitude of the variable magnetic flux. Moreover, since the amplitude of the variable magnetic flux flowing from the second permanent magnet through the third permanent magnet and flowing through the first permanent magnet is reduced, the amplitude of the alternating magnetic flux flowing through the outer yoke is also reduced, and the iron loss of the outer yoke is also reduced. As a result, a highly efficient reciprocating drive mechanism can be provided.

  In addition, the maximum magnetic flux amount of the alternating magnetic flux flowing through the outer yoke can be reduced to reduce the magnetic flux passage cross-sectional area of the outer yoke. The outer yoke becomes smaller and lighter and the efficiency of the reciprocating drive mechanism is high. A dynamic drive mechanism can be provided.

  Further, in the invention according to claim 2, the reciprocating drive mechanism is, for example, next to the second permanent magnet in which the first permanent magnet, the third permanent magnet, and the second permanent magnet are sequentially arranged. A plurality of third permanent magnets adjacent to the first permanent magnet and the second permanent magnet are arranged so as to sequentially arrange the third permanent magnet and the first permanent magnet. Thereby, a large magnetic thrust obtained by multiplying the magnetic thrust obtained when there is one third permanent magnet by the number of the third permanent magnets can be obtained.

  In the invention according to claim 3, since the holding member is a magnetic material, the holding member acts as an inner yoke, and the holding member includes a coil arranged in each slot, although an alternating current is applied. Fluctuating magnetic flux in a constant direction (the magnetization direction of the third permanent magnet) always flows. Thereby, the amplitude and the maximum magnetic flux amount of the fluctuation magnetic flux flowing through the holding member are reduced compared to the amplitude and the maximum magnetic flux amount of the alternating magnetic flux of the electromagnetic actuator (reciprocating drive mechanism) according to the prior art. The iron loss of the holding member decreases due to the decrease in the amplitude of the fluctuation magnetic flux. Further, since the amplitude of the changing magnetic flux flowing through the holding member is reduced, the amplitude of the alternating magnetic flux flowing through the outer yoke is also reduced, and the iron loss of the outer yoke is also reduced. As a result, a highly efficient reciprocating drive mechanism can be provided.

  Further, since the maximum magnetic flux amount of the holding member is smaller than the maximum magnetic flux amount of the prior art, the holding member can avoid magnetic saturation with a smaller magnetic flux passage cross-sectional area than the prior art. Thereby, the outer diameter of a needle | mover can be reduced and a needle | mover becomes small and lightweight. Similarly, since the maximum amount of magnetic flux of the outer yoke is also reduced, the outer yoke can avoid magnetic saturation with a smaller magnetic flux passage cross-sectional area than the prior art. The stator becomes smaller and lighter by reducing the magnetic flux passage cross-sectional area of the stator and reducing the outer diameter of the mover. As described above, a small and light linear motor can be provided.

  In the invention according to claim 4, since the regenerative refrigerator is compressed with a piston that is reciprocally driven by a reciprocating drive mechanism that is highly efficient and small and light, and obtains refrigeration, it is highly efficient and small and light. A regenerative refrigerator can be provided.

  In the invention according to claim 5, the Stirling refrigerator or the Stirling type pulse tube refrigerator is highly efficient, refrigerated by compressing the working gas with a piston that is reciprocated by a reciprocating drive mechanism that is highly efficient and small and light. Therefore, a highly efficient, small and light cold storage type refrigerator can be provided.

  In the invention according to claim 6, since the compressor compresses the working gas with a piston that is reciprocally driven by a reciprocating drive mechanism that is highly efficient and small and lightweight, a highly efficient small and light compressor can be provided. .

It is explanatory drawing of the Stirling refrigerator using the reciprocating drive mechanism which concerns on Example 1 of this invention, and its reciprocating drive mechanism. It is explanatory drawing of the magnetic flux produced by the permanent magnet of the linear motor of FIG. It is magnetic flux explanatory drawing of the linear motor of FIG. 1 at the time of coil energization. It is magnetic flux explanatory drawing of the linear motor of FIG. 1 at the time of coil energization. It is a fragmentary sectional view which shows the main dimensions of the linear motor of FIG. FIG. 2 is a diagram showing the relationship between (inner yoke thickness / permanent magnet outer diameter), thrust coefficient, and (thrust coefficient / inner yoke mass) of the linear motor of FIG. 1. FIG. 2 is a diagram showing a relationship between (permanent magnet thickness / permanent magnet outer diameter), thrust coefficient, and (thrust coefficient / inner yoke mass) of the linear motor of FIG. 1. It is a fragmentary sectional view of the modification of the needle | mover of the linear motor of FIG. It is explanatory drawing of the Stirling type pulse tube refrigerator using the reciprocating drive mechanism of FIG. It is explanatory drawing of the Stirling refrigerator based on Example 2 using the reciprocating drive mechanism of FIG. It is explanatory drawing of the Stirling refrigerator using the reciprocating drive mechanism which concerns on Example 3 of this invention. It is explanatory drawing of the compressor which concerns on Example 4 using the reciprocating drive mechanism of FIG.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram of a reciprocating drive mechanism and a Stirling refrigerator using the reciprocating drive mechanism according to Embodiment 1 of the present invention. In the figure, the black arrow indicates the magnetization direction of the permanent magnet, and the tip of the arrow is the N pole. As shown in FIG. 1, the Stirling refrigerator 1 (cold storage type refrigerator) connects a compression unit 10 and a refrigeration generation unit 50 with a pipe 11 and is filled with, for example, helium as a working gas. The compression unit 10 includes a linear motor 20 (reciprocating drive mechanism), a movable body 35 including a mover 30 of the linear motor 20, and a cylinder 40.

  The linear motor 20 includes a stator 21 and a mover 30. The stator 21 has a cylindrical shape, an outer yoke piece 23 made of a magnetic material having an H-shaped cross section in the axial direction, and a concave section in the axial direction fixed to both ends of the outer yoke piece 23 in the axial direction. An outer yoke 25 composed of magnetic material outer yoke pieces 22 and 24 and coils 26 and 27 are provided. The inner peripheral sides of the outer yoke element pieces 22, 23, 24 are respectively a pair of magnetic pole pieces 22a (first magnetic pole piece), 23a (first magnetic pole piece) and a pair of magnetic pole pieces 23b (second magnetic pole piece), 24a ( The magnetic pole pieces 22a and 23a make a pair and face each other through a gap 21a (distance), and the pole pieces 23b and 24a also make a pair and face each other through a gap 21b (distance). . In the coil 26, the coated conductor is wound around the magnetic pole pieces 22 a and 23 a around the axis of the stator 21, and is sandwiched between slots 28 formed by the outer yoke pieces 22 and 23. Similarly, the coil 27 is wound around a slot 29 formed by the outer yoke element pieces 23 and 24, with the coated conductors wound around the pole pieces 23b and 24a around the axis of the stator 21. The coils 26 and 27 have the same wire diameter, overall length, and number of turns.

  The mover 30 includes a cylindrical holding member 31, a cylindrical permanent magnet 32 (first permanent magnet), a permanent magnet 33 (third permanent magnet), and a permanent magnet 34 (second permanent magnet). Inserted. And the adhesive material is apply | coated to the internal peripheral surface of each permanent magnet 33-34, and it mutually fixes. Thereby, the permanent magnets 32 to 34 are arranged coaxially with the axis X. The permanent magnets 32 and 34 are magnetized in the radial direction with opposite magnetization directions. In FIG. 1, the permanent magnet 32 is magnetized to the N pole on the outer peripheral surface and the S pole on the inner peripheral surface, and the permanent magnet 34 is magnetized to the S pole on the outer peripheral surface and the N pole on the inner peripheral surface. . The permanent magnet 33 is magnetized in the direction of the axis X when the inner peripheral surface of the permanent magnet 32 is the S pole and the inner peripheral surface of the permanent magnet 34 is the N pole, and the end surface of the permanent magnet 33 on the permanent magnet 34 side is the S pole. The end surface of the permanent magnet 33 on the permanent magnet 32 side is magnetized to the N pole. That is, it is magnetized in the direction from the permanent magnet 34 to the permanent magnet 32 (FIG. 1). When the inner peripheral surface of the permanent magnet 32 is N-pole and the inner peripheral surface of the permanent magnet 34 is S-pole, the permanent magnet 33 is magnetized in the direction of the axis X from the permanent magnet 32 to the permanent magnet 34 (not shown). ). The axis X is a common axis for the holding member 31, the permanent magnets 32 to 34, the piston 36, the piston guide 37, the cylinder 40, and the outer yoke 25.

  The holding member 31 may be either a magnetic material or a nonmagnetic material. As will be described later, when the amount of magnetic flux of the linear motor 20 is large, the holding member 31 is preferably a magnetic material, and when the movable body 35 reciprocates at a high frequency, the holding member 31 is preferably a non-magnetic material.

  In FIG. 1, the permanent magnets 32, 33, and 34 are separate members, and the movable magnet 30 is configured by fixing the permanent magnet 32 and the permanent magnet 34 to both ends of the permanent magnet 33. However, it may be formed by partially changing the magnetization direction with one permanent magnet. That is, both sides of the cylindrical permanent magnet may be magnetized in opposite directions in the radial direction, and the portion magnetized in the opposite direction in the radial direction may be magnetized in the above-described direction in the axial direction. In this case, the holding member 31 may or may not be provided.

  The permanent magnets 32, 33, and 34 are not divided in a cylindrical shape, but may be divided in the radial direction or in the axial direction.

  Moreover, although the permanent magnets 32, 33, and 34 are cylindrical, plate-shaped permanent magnets may be equally arranged on the same circumference.

  The movable body 35 includes a cup-shaped piston 36 made of a non-magnetic material and a non-lubricated sliding material by applying an adhesive to the outer peripheral surfaces of both ends of the holding member 31 of the movable element 30, and a cylindrical piston guide 37. And inserted and fixed. The outer diameters of the permanent magnets 32, 33, and 34 are equal, and the outer diameters of the piston 36 and the piston guide 37 are slightly larger than the outer diameters of the permanent magnets 32, 33, and 34. The cylinder 40 is configured by hermetically fixing the end plate 42 to the opening end of the cylinder body 41 having a head 41 a at one end, and the stator 21 is mounted on the outer peripheral surface of the cylinder 40. On the inner peripheral surface of the cylinder 40, the movable body 35 is inserted so as to be able to reciprocate in the axis X direction so that the piston 36 faces the head 41a. The minute gap between the inner peripheral surface of the cylinder 40 and the outer peripheral surfaces of the piston 36 and the piston guide 37 has a clearance seal function for sealing helium.

  The coils 26 and 27 are connected to an alternating current source (not shown). The coils 26 and 27 are energized with a current having the same amplitude and a phase shifted by 180 degrees. When the coils 26 and 27 are not energized, the movable body 35 is in the neutral position. That is, the permanent magnets 32 and 34 pass through the tube wall of the cylinder 40 in the axial direction, and the permanent magnet 32 and the magnetic pole pieces 22a and 23a, and the permanent magnet 34 and the magnetic pole pieces 24a and 23b intervene the tube wall of the cylinder 40. Each is located with an overlap. In this state, the neutral position in the axial direction of the mover 30 and the neutral position in the axial direction of the outer yoke 25 coincide with each other through the tube wall of the cylinder 40. The cylinder 40 and the movable body 35 form a compression chamber 43 on the left side of the drawing with the head portion of the piston 36 as a boundary, and a buffer chamber 44 on the right side of the drawing. The compression chamber 43 is connected to the refrigeration generating unit 50 via a flow path hole 41 b provided in the head 41 a of the cylinder body 41 and the pipe 11.

  The refrigeration generator 50 is configured to communicate with the compression chamber 51 in sequence with a radiator 52, a regenerator 53, a heat absorber 54, and an expansion chamber 55. The expansion chamber 55 is surrounded by the upper surface side of the displacer 56 (expansion side piston) made of a non-lubricated sliding material, the displacer cylinder 57 (expansion side cylinder), and the head 58 c of the case 58. The compression chamber 51 and the radiator 52 are communicated with the compression chamber 43 of the compression unit 10 via the pipe 11. The compression chamber 51 is surrounded by a lower surface side of the displacer 56, a displacer cylinder 57, a partition wall 59, and a rod 63 connected to the lower surface of the displacer 56. The radiator 52 is configured by fixing a fin member 52 a to an inner peripheral surface 58 a of a case 58 between the lower end of the regenerator 53 and the lower end of the displacer cylinder 57. The regenerator 53 is configured by filling the cylindrical space formed by the case 58 and the displacer cylinder 57 between the radiator 52 and the heat absorber 54 with a regenerator element 53a. The radiator 54 is configured by fixing a fin member 54 a to an inner peripheral surface 58 b of the case 58 between the upper end of the regenerator 53 in the drawing and the upper end of the displacer cylinder 57 in the drawing.

  The displacer 56 is connected to driving means 60 provided in the buffer chamber 64 via a rod 63. The driving means 60 includes a spring holding member 61 fixed to an end portion of a rod 63 that passes through a hole of the partition wall 59 and protrudes into the buffer chamber 64, and a compression coil spring 62 in which one end abuts on both end faces of the spring holding member 61. 62, the other ends of the compression coil springs 62, 62 abut against the end surfaces of the partition wall 59 and the case 58, respectively.

  The buffer chamber 64 is formed so as to be surrounded by a case 58, a partition wall 59, a rod 63, and a rod seal 65 provided on the partition wall 59. The helium in the buffer chamber 64 and the compression chamber 51 is sealed by the rod seal 65. The compression chamber 51 and the expansion chamber 55 are sealed with helium by a clearance seal formed by a minute gap between the inner peripheral surface of the displacer cylinder 57 and the outer peripheral surface of the displacer 56.

  Next, the operation and effect of the linear motor 20 according to the first embodiment of the present invention will be described. 2 to 4 are partial cross-sectional explanatory views of the operation of the linear motor 20, in which the cylinder 40, the piston 36, the piston guide 37, and the cross-sectional hatching are omitted for easy understanding. 2 to 4, black arrows in the permanent magnets 32, 33, and 34 indicate the magnetization direction, and the tip side of the arrow is an N pole. 3 and 4, the black symbols on the circles and the cross symbol on the circles indicate the direction of current flow, and the black symbols on the circles indicate the current flow from the back of the paper to the front. The symbol X in the circle indicates the current flow flowing from the front to the back of the page. As described above, the holding member 31 may be either a magnetic material or a non-magnetic material, but here the material of the holding member 31 is a magnetic material. Therefore, the holding member 31 functions as an inner yoke of the mover 30. 2 to 4, the gap G1 (distance) between the left side of the permanent magnet 32 and the outer yoke piece 22a, the right side from the center side of the permanent magnet 32, the left side of the permanent magnet 33, and the outer yoke piece 23a. G2a (distance) of the permanent magnet 34, the gap G2b (distance) between the right side of the permanent magnet 33 and the right side of the permanent magnet 33 and the outer yoke piece 23b, and the gap G3 between the right side of the permanent magnet 34 and the outer yoke piece 24a. (Distance) forms a magnetic gap through which the magnetic flux passes. The gaps G1, G2a, G2b, and G3 are gaps through the tube wall of the cylinder 40.

  FIG. 2 is an explanatory diagram of magnetic flux generated by the permanent magnets 32 to 34 of the linear motor 20 at the neutral position of the mover 30. FIG. 2A shows the magnetization directions of the permanent magnets 32 to 34. 3 and 4 are the same as those in FIG. 2A. FIG. 2B shows the magnetic flux (bold solid line and bold broken line) generated by the permanent magnets 32 to 34, and the arrows show the flow of the magnetic flux.

  As shown in FIG. 2 (a), the permanent magnet 32 is magnetized to the south pole on the inner peripheral surface and the north pole on the outer peripheral surface, and the permanent magnet 34 is magnetized to the north pole on the inner peripheral surface and the outer peripheral surface to the south pole. . The permanent magnet 33 is magnetized so that the end surface on the permanent magnet 34 side is an S pole and the end surface on the permanent magnet 32 side is an N pole.

  Since the permanent magnets 32 and 34 have the same holding force and dimensions, the magnetic flux generated by the permanent magnet 32 and the magnetic flux generated by the permanent magnet 34 are the same in the opposite directions in the disk portion 23c of the outer yoke piece 23. The magnetic fluxes cancel each other and almost no magnetic flux is generated. Therefore, as shown in FIG. 2B, the permanent magnets 32 and 34 generate a clockwise closed-loop magnetic flux Φ indicated by a thick solid line in the outer yoke pieces 22, 23 and 24 and the mover 30. The magnetic flux Φ crosses the gap G3 and the permanent magnet 34 from the magnetic pole piece 24a and flows into the holding member 31 (hereinafter referred to as the inner yoke 31) which is an inner yoke. The magnetic flux Φ flowing into the inner yoke 31 passes through the inner yoke 31 to the left side of the inner yoke 31, and flows from there to the magnetic pole piece 22a across the permanent magnet 32 and the gap G1. After passing through the yoke piece 23 and the outer yoke piece 24, it returns to the magnetic pole piece 24a and makes a round. Further, the permanent magnets 32, 33, 34 generate the clockwise magnetic fluxes Ω, Γ indicated by thick broken lines in the outer yoke piece 23 and the mover 30. The magnetic flux Ω forms a closed loop that sequentially passes from the right side of the permanent magnet 32 to the right side of the permanent magnet 32 through the gap G2a, the magnetic pole pieces 23a and 23b, the gap G2b, the left side of the permanent magnet 34, and the inner yoke 31. The magnetic flux Γ sequentially forms a closed loop from the permanent magnet 33 that passes through the right end side of the permanent magnet 32, the gap G2a, the magnetic pole pieces 23a and 23b, the gap G2b, and the left end side of the permanent magnet 34 and returns to the permanent magnet 33 again. And the density of the magnetic force lines of the gaps G1 and G3 by the permanent magnets 32 and 34 is the same, but the directions are opposite. Moreover, the density of the magnetic lines of the gap G2a and the gap G2b by the permanent magnets 32, 33, and 34 is the same and the directions are opposite. Therefore, when the coils 26 and 27 are not energized, no magnetic force in the reciprocating direction is generated in the mover 30 and the mover 30 remains in the neutral position.

  FIG. 3 is a partial cross-sectional explanatory diagram of the magnetic flux of the linear motor 20 when the coil is energized, and the magnetization directions of the permanent magnets 32 to 34 are the same as those in FIG. FIG. 3A shows a magnetic flux diagram generated by the currents of the coils 26 and 27. As shown in FIG. 3A, when the mover 30 is in the neutral position, the coils 26 and 27 are supplied with direct currents having the same current value in opposite directions. Then, a clockwise closed-loop magnetic flux Ψ1 indicated by a thick solid line by the coil 26 and a counterclockwise closed-loop magnetic flux Ψ2 indicated by a thick broken line by the coil 27 are generated. The magnetic flux Ψ1 is sequentially applied from the left side of the permanent magnet 32 to the gap G1, the magnetic pole piece 22a, the outer yoke piece 22, the disk portion 23c of the outer yoke piece 23, the magnetic pole piece 23b, the gap G2b, the left side of the permanent magnet 34, the inner yoke. After passing through 31, it returns to the left side of the permanent magnet 32 and makes a round. The magnetic flux Ψ2 is sequentially applied from the center side of the permanent magnet 34 to the right side of the inner yoke 31, the right end side of the inner yoke 31 and the right end side of the magnetic pole piece 24a, the right end side of the magnetic pole piece 24a, the outer yoke piece 24, the outer yoke. After passing through the disc portion 23c, the magnetic pole piece 23b, and the gap G2b of the element piece 23, it returns to the center side of the permanent magnet 34 and makes a round. The magnetic flux Ψ1 passes through the gap G1 and the gap G2b, and the magnetic flux Ψ2 passes through the gap G2b and the gap G3b. The coils 26 and 27 have the same wire diameter, overall length, and number of turns, and the magnetic resistance of the gap G3b is larger than the magnetic resistance of the gap G1, so that the magnetic flux amount of the magnetic flux ψ1 is larger than the magnetic flux amount of the magnetic flux ψ2.

  FIG. 3B is an explanatory diagram of the moving direction of the mover 30 when the coil is energized, and shows magnetic fluxes Φ, Ω, and Γ by the permanent magnets 32 to 34 at the neutral position of the mover 30. As shown in FIG. 3B, when a current flows through the coils 26 and 27, the coil 26 receives magnetic force from the magnetic fluxes Φ, Ω, and Γ of the permanent magnets 32 to 34 and the magnetic flux Ψ 2 of the coil 27. Is subjected to magnetic force by the magnetic fluxes Φ, Ω, Γ of the permanent magnets 32 to 34 and the magnetic flux Ψ 1 of the coil 26. That is, when a direct current of the same current value (the same current as that in FIG. 3A) is applied to the coils 26 and 27 in opposite directions, the coil 26 is driven by the magnetic flux Φ of the gap G1 based on Fleming's left-hand rule. While receiving the magnetic force in the J direction, the magnetic forces due to the magnetic fluxes Ω and Γ in the gap G2a and G2b cancel each other and hardly act on the coil 26, and the magnetic flux Ψ2 in the gap G2b and the gap G3b (FIG. 3A). The magnetic forces generated by the two cancel each other and hardly act on the coil 26. As a result, the coil 26 receives the magnetic force in the direction of arrow J.

  Similarly, based on Fleming's left-hand rule, the coil 27 receives a magnetic force in the J direction due to the magnetic flux Φ of the gap G3, but the magnetic forces due to the magnetic fluxes Ω and Γ of the gap G2a and the gap G2b cancel each other out. Hardly acts, and the magnetic force due to the magnetic flux Ψ1 (FIG. 3A) in the gap G2b and the gap G1 cancels each other and hardly acts on the coil 27. As a result, the coil 27 receives the magnetic force in the direction of arrow J. Thus, the coils 26 and 27 receive the magnetic force in the arrow J direction by the magnetic flux Φ, but the coils 26 and 27 are sandwiched by the stator 21 and cannot move, so the mover 30 receives the magnetic force in the arrow M direction and moves to the arrow. Move in the M direction.

  FIG. 3 (c) shows a magnetic flux diagram in which the magnetic fluxes Ψ1, Ψ2 by the coils 26, 27 in FIG. 3 (a) and the magnetic fluxes Φ, Ω, Γ by the permanent magnets 32-34 in FIG. 3 (b) are combined. As shown in FIG. 3 (c), in the magnetic circuit of the stator 21 and the mover 30, a clockwise closed loop combined magnetic flux (Ψ1 + Φ) indicated by a thick solid line and a counterclockwise closed loop combined magnetic flux Λ2 are generated. At the same time, a closed loop magnetic flux Ω, Γ in the clockwise direction in the figure remains. Since the flow directions of the magnetic flux Φ and the magnetic flux Ψ2 are opposite, the magnetic flux amount of the magnetic flux (ψ2-Φ) becomes substantially zero, and the magnetic flux Λ2 is synthesized, but the magnetic flux amount of the synthetic magnetic flux Λ2 is the combined magnetic flux (Ψ1 + Φ). Small compared. The direction of the combined magnetic flux (Ψ1 + Φ) having a large amount of magnetic flux flowing through the inner yoke 31 is the same as the magnetization direction of the permanent magnet 33.

  FIG. 3D shows a state in which the mover 30 in FIG. 3C moves in the direction of arrow M and the external force F in the N direction acting on the mover 30 and the magnetic force Fa in the M direction are balanced and stopped. Similarly to FIG. 3C, the magnetic flux Φa (not shown) by the permanent magnets 32 to 34 at the balance stop position and the magnetic fluxes ψa1 and ψa2 (not shown) by the coils 26 and 27 are synthesized. As a result of this synthesis, as shown in FIG. 3D, a clockwise closed loop combined magnetic flux (Ψa1 + Φa) indicated by a thick solid line and a counterclockwise closed loop combined magnetic flux Λ2a are generated and a clockwise closed loop magnetic flux Ωa shown in FIG. Γa remains. The direction of the combined magnetic flux (Ψa1 + Φa) flowing through the inner yoke 31 is the same as the magnetization direction of the permanent magnet 33, and the amount of magnetic flux is larger than the combined magnetic flux Λ2a.

  FIG. 4 is a partial cross-sectional explanatory view of magnetic flux when a direct current having the same current value as that of FIG. FIG. 4A shows a magnetic flux diagram generated by the currents of the coils 26 and 27. As shown in FIG. 4A, in the state where the mover 30 is located at the neutral position, the coils 26 and 27 are supplied with direct currents having the same current value in opposite directions. As a result, a counterclockwise closed loop magnetic flux Ψ1 due to the coil 26 and a clockwise closed loop magnetic flux Ψ2 due to the coil 27 are generated. The magnetic flux Ψ1 is sequentially applied from the center side of the permanent magnet 32 to the gap G2a, the magnetic pole piece 23a, the disc portion 23c of the outer yoke piece 23, the outer yoke piece 22, the magnetic pole piece 22a, the left end side of the magnetic pole piece 22a and the inner yoke 31. After passing through the gap G1b between the left end side and the inner yoke 31, it returns to the center side of the permanent magnet 32 and makes a round. The magnetic flux Ψ2 is sequentially applied from the right side of the permanent magnet 34 to the inner yoke 31, the right side of the permanent magnet 32, the gap G2a, the magnetic pole piece 23a, the disk portion 23c of the outer yoke piece 23, the outer yoke piece 24, and the outer yoke piece 24. The magnetic pole piece 24a passes through the gap G3 and returns to the right side of the permanent magnet 34 to make a round. The magnetic flux Ψ1 passes through the gap G1b and the gap G2a, and the magnetic flux Ψ2 passes through the gap G2a and the gap G3. The coils 26 and 27 have the same wire diameter, total length, and number of turns, and the magnetic resistance of the gap G1b is larger than the magnetic resistance of the gap G3. Therefore, the magnetic flux amount of the magnetic flux ψ2 is larger than the magnetic flux amount of the magnetic flux ψ1.

  FIG. 4B is an explanatory diagram of the moving direction of the mover 30 when the coil is energized, and shows magnetic fluxes Φ, Ω, and Γ by the permanent magnets 32 to 34 at the neutral position of the mover 30. As shown in FIG. 4B, when current flows through the coils 26 and 27, the coil 26 is caused by the magnetic fluxes Φ, Ω, and Γ of the permanent magnets 32 to 34 and the magnetic flux Ψ2 of the coil 27 (FIG. 4A). Under the magnetic force, the coil 27 receives the magnetic force due to the magnetic fluxes Φ, Ω, Γ of the permanent magnets 32 to 34 and the magnetic flux ψ1 (FIG. 4A) of the coil 26. That is, when a direct current of the same current value (the same current as in FIG. 4A) is applied to the coils 26 and 27 in opposite directions, the coil 27 is subjected to K by the magnetic flux Φ of the gap G3 based on Fleming's left-hand rule. However, the magnetic forces due to the magnetic fluxes Ω and Γ in the gap G2a and the gap G2b cancel each other and hardly act on the coil 27, and the magnetic flux Ψ1 in the gap G2a and the gap G1b (FIG. 4A). The magnetic force due to the above cancels out and hardly acts on the coil 27. As a result, the coil 27 receives a magnetic force in the arrow K direction.

  Similarly, based on Fleming's left-hand rule, the coil 26 receives a magnetic force in the K direction due to the magnetic flux Φ in the gap G1, but the magnetic forces due to the magnetic fluxes Ω and Γ in the gap G2a and the gap G2b cancel each other. Almost does not act, the magnetic force due to the magnetic flux Ψ2 (FIG. 4A) in the gap G2a and the gap G3 cancels each other, and hardly acts on the coil 26. As a result, the coil 26 receives a magnetic force in the arrow K direction. As described above, the coils 26 and 27 receive the magnetic force in the arrow K direction due to the magnetic flux Φ, but the coils 26 and 27 are sandwiched by the stator 21 and cannot move, so that the mover 30 receives the magnetic force in the arrow N direction. Move in the direction of arrow N.

  FIG. 4C shows a magnetic flux diagram in which the magnetic fluxes Ψ1, Ψ2 by the coils 26, 27 in FIG. 4A and the magnetic fluxes Φ, Ω, Γ by the permanent magnets 32-34 in FIG. 4B are combined. As shown in FIG. 4C, in the magnetic circuit of the stator 21 and the mover 30, a clockwise closed loop combined magnetic flux (Ψ2 + Φ) and a counterclockwise closed loop combined magnetic flux Λ1 are generated. The surrounding closed-loop magnetic flux Ω and Γ remain. Since the flow directions of the magnetic flux Φ and the magnetic flux Ψ1 are opposite, the magnetic flux amount of the magnetic flux (Ψ1-Φ) is substantially 0, and the magnetic flux Λ1 is synthesized, but the magnetic flux amount of the synthesized magnetic flux Λ1 is the combined magnetic flux (Ψ2 + Φ). Small compared. The direction of the combined magnetic flux (Ψ2 + Φ) having a large amount of magnetic flux flowing through the inner yoke 31 is the same as the magnetization direction of the permanent magnet 33, and the combined magnetic flux (Ψ1 + Φ) of FIG. Same as direction.

  FIG. 4D shows a state in which the mover 30 in FIG. 4C moves in the direction of arrow N, and the external force F in the M direction acting on the mover 30 and the magnetic force Fb in the N direction stop in balance. Similar to FIG. 4C, the magnetic flux Φb (not shown) by the permanent magnets 32 to 34 at the balance stop position and the magnetic fluxes ψb1 and ψb2 (not shown) by the coils 26 and 27 are synthesized. As a result of this synthesis, as shown in FIG. 4 (d), a combined magnetic flux (Ψb2 + Φb) in the clockwise direction shown in the drawing and a combined magnetic flux Λ1b in the counterclockwise direction in the drawing are generated, and magnetic fluxes Ωb and Γb in the clockwise clockwise loop remain. To do. The direction of the combined magnetic flux (Ψb2 + Φb) flowing through the inner yoke 31 is the same as the magnetization direction of the permanent magnet 33, and is the same as the direction of the combined magnetic flux (Ψa1 + Φa) flowing through the inner yoke 31 in FIG. Further, the composite magnetic flux (Ψb2 + Φb) is larger than the magnetic flux amount of the composite magnetic flux Λ1b. The magnetic force Fa (FIG. 3D) and the magnetic force Fb (FIG. 4D) are magnetic thrusts generated by the linear motor 20 when energized, having the same magnitude and opposite directions.

  3 and 4, when an alternating current whose phase is shifted by 180 degrees is applied to the coils 26 and 27, the mover 30 reciprocates.

  As described above, the following effects are produced. That is, when the holding member 31 is a magnetic material, magnetic fluxes in opposite directions are generated in the outer yoke 25 by applying alternating currents that are 180 degrees out of phase to the coils 26 and 27. Although the current is alternating (the current is ± changed), this magnetic flux has a fluctuating magnetic flux with a large magnetic flux amount in the same direction as the magnetization direction of the permanent magnet 33 (the direct current component has an alternating current component). Applied magnetic flux) is always generated. On the other hand, in the conventional linear motor (electromagnetic actuator), an alternating magnetic flux (magnetic flux whose direction is changed) is generated in the inner yoke. Therefore, under the same magnetic thrust, the amplitude and the maximum amount of magnetic flux in a certain direction flowing through the inner yoke 31 of the linear motor 20 of the present invention are smaller than the amplitude and the maximum amount of magnetic flux in the prior art. Due to the decrease in the amplitude and the maximum magnetic flux amount of the fluctuation magnetic flux, the amplitude and the maximum magnetic flux amount of the fluctuation magnetic flux in the outer yoke 25 are also reduced. As a result, the iron loss of each of the inner yoke 31 and the outer yoke 25 generated by the fluctuating magnetic flux is reduced, so that a highly efficient linear motor 20 can be provided.

  In addition, since the maximum magnetic flux amount of the inner yoke 31 is smaller than the maximum magnetic flux amount of the prior art, the inner yoke 31 can have a smaller magnetic flux passage cross-sectional area than the prior art, and magnetic saturation can be avoided. As a result, the outer diameter of the mover 30 is reduced. Similarly, since the maximum magnetic flux amount of the outer yoke 25 is also reduced, the outer yoke 25 can avoid magnetic saturation with a smaller magnetic flux passage cross-sectional area than the prior art, and the outer diameter of the mover 30 can be reduced. Smaller and lighter. Since the linear motor 20 is highly efficient as described above, a small and lightweight linear motor 20 can be provided.

  In the linear motor of the prior art, the magnetic gap on the inner peripheral surface side of the mover (magnetic gap between the inner peripheral surface of the mover and the inner yoke) and the magnetic gap on the outer peripheral surface side of the mover (mover) Therefore, the linear motor becomes large in order to increase the magnetic resistance of the magnetic circuit and obtain a predetermined magnetic thrust. However, the linear motor 20 of the present embodiment has a magnetic gap on the outer peripheral surface side of the mover 30 (a magnetic gap having one diameter between the outer peripheral surface of the permanent magnets 32 to 34 of the mover 30 and the inner peripheral surface of the stator 21). Therefore, the magnetic resistance is reduced, and the linear motor 20 becomes smaller and lighter.

  The operations and effects described above are for the case where the holding member 31 is a magnetic material. However, even when the holding member 31 is a non-magnetic material, it flows through the inner yoke 31 (the magnetic material holding member 31) described above. Since the magnetic flux generated by the alternating current of the coils 26 and 27 and the magnetic flux generated by the permanent magnets 32 to 34 sequentially flow to the permanent magnets 34, 33, and 32, the linear motor 20 is the same as when the holding member 31 is a magnetic material. Effects and effects. That is, by applying an alternating current whose phase is shifted by 180 degrees to the coils 26 and 27, magnetic fluxes in opposite directions are generated in the coils 26 and 27. In spite of the alternating current of the magnetic flux, the permanent magnets 34, 33, 34 always generate a variable magnetic flux in the same direction as the magnetization direction of the permanent magnet 33. Since the amplitude and the maximum magnetic flux amount of the fluctuation magnetic flux are smaller than the amplitude and the maximum magnetic flux amount of the alternating magnetic flux of the prior art, the same effect as the case where the holding member 31 is a magnetic material is produced.

  The movable body 35 including the movable element 30 is a total of a magnetic spring of the linear motor 20, a spring obtained by synthesizing a helium gas spring acting on the front surface and the rear surface of the movable body 35, and the movable body 35 including the movable element 30. A vibration system having a natural frequency with the mass is formed. By operating near this natural frequency, the amplitude of the reciprocating motion of the movable body 35 increases and the efficiency of the linear motor 20 is improved. Furthermore, by using a lightweight material such as resin for the holding member 31, the mover 30 becomes lighter and the natural frequency of the movable body 35 increases, and the movable body 35 is driven to reciprocate in the vicinity of the increased natural frequency. As a result, the amount of refrigeration generated in the expansion chamber 55 increases.

  Further, when the holding member 31 is a magnetic material and the amount of magnetic flux Ψ1, Ψ2 by the coils 26, 27 is large, the magnetic fluxes Ψ1, Ψ2 flow to the holding member 31, so that the magnetic flux passage cross-sectional area of the holding member 31 is appropriately secured. Thus, magnetic saturation can be avoided without increasing the cost. Therefore, it is suitable when the magnetic flux amount of the magnetic fluxes Ψ1, Ψ2 by the coils 26, 27 is large.

  Further, in FIG. 1, a permanent magnet 32 and a permanent magnet 34 are fixed to both ends of a permanent magnet 33, and a mover 30 provided with three permanent magnets is magnetized in one permanent magnet in the three directions described above to move. You may comprise a child. When the holding member 31 is provided on the inner diameter surface of the permanent magnet and the holding member 31 is a magnetic material, the operation and effect are the same as in the case where the holding member 31 is a magnetic material. Further, when the holding member 31 is a nonmagnetic material, the operation and effect are the same as in the case where the holding member 31 is a nonmagnetic material. The operation when the holding member 31 is not provided is the same as the case where the above-described holding member 31 is a nonmagnetic material, and in addition to the same effect as the nonmagnetic material, the structure of the mover is simplified.

  FIG. 5 is a partial cross-sectional view showing the main dimensions of the linear motor 20 of FIG. 1, and the holding member 31 is an inner yoke made of a magnetic material. In FIG. 5, D is the diameter of the permanent magnets 32 to 34, t1 is the thickness of the inner yoke (when the holding member 31 is a magnetic material), t2 is the thickness of the permanent magnets 32 to 34, and C is the permanent magnet 33. Is the length of In the neutral position of the mover 30, A is the allowance for the permanent magnet 32 and the pole piece 22a and the allowance for the permanent magnet 34 and the pole piece 24a, and B is the allowance for the permanent magnet 32 and the pole piece 23a. This is the overlap margin between the magnet 34 and the magnetic pole piece 23b.

  FIG. 6 is a diagram showing the relationship between (inner yoke thickness / permanent magnet outer diameter), thrust coefficient, and (thrust coefficient / inner yoke mass) of the linear motor 20. FIG. 7 is a diagram showing the relationship between (permanent magnet thickness / permanent magnet outer diameter), thrust coefficient, and (thrust coefficient / inner yoke mass) of the linear motor 20. 6 and 7, the thick solid line indicates (thrust coefficient / inner yoke mass), and the solid line indicates the thrust coefficient. The thrust coefficient is 1 AT (AT is an ampere turn, current is a unit of A, T is the number of turns of the coil in the turn), that is, current 1 A (1 A of the absolute value of the current of the coils 26 and 27), coil 1 Magnetic thrust per winding.

  As shown in FIG. 6, when (inner yoke thickness t1 / permanent magnet outer diameter D) is 20% or less, the thrust coefficient increases rapidly, and (thrust coefficient / inner yoke mass) maintains a high value. When (inner yoke thickness t1 / permanent magnet outer diameter D) exceeds 20%, the thrust coefficient reaches a peak and (thrust coefficient / inner yoke mass) decreases. Therefore, in order to make the inner yoke 31 small and light, the inner yoke thickness t1 is preferably 20% or less of the outer diameter D of the permanent magnets 32-34.

  As shown in FIG. 7, when (permanent magnet thickness t2 / permanent magnet outer diameter D) is in the range of 3% to 20%, the thrust coefficient increases and (thrust coefficient / inner yoke mass) is also high. When (permanent magnet thickness t2 / permanent magnet outer diameter D) exceeds 20%, the thrust coefficient reaches a peak and (thrust coefficient / inner yoke mass) decreases. Therefore, in order to make the inner yoke small and light while securing the magnetic thrust, the thickness t2 of the permanent magnets 32 to 34 is preferably in the range of 3% to 20% of the outer diameter D of the permanent magnets 32 to 34.

  Further, when the length C of the permanent magnet 33 is 3% to 130% of the length of the permanent magnets 32 and 34, the highly efficient linear motor 20 is obtained.

  The overlap margins A and B between the pole pieces 22a and 23a and the permanent magnet 32 and the overlap margins A and B between the pole pieces 24a and 23b and the permanent magnet 34 are 60% to 180% of the maximum stroke of the mover 30. An efficient linear motor 20 with a high range is obtained. Further, the overlap margin A and the overlap margin B are such that B ≧ A increases the efficiency of the linear motor 20.

  Next, the operation and effect of the Stirling refrigerator 1 according to the first embodiment of the present invention will be described. The Stirling refrigerator 1 is operated in the vicinity of the natural frequency of the movable body 35 by substantially matching the natural frequency of the displacer 56 with the natural frequency of the movable body 35. An alternating current having the same amplitude and phase shifted by 180 degrees is applied to the coils 26 and 27 at a frequency near this natural frequency. Then, the movable body 35 reciprocates and the displacer 56 also reciprocates. The movable body 35 and the displacer 56 have a phase relationship in which the scavenging volume of the expansion chamber 55 advances in phase by approximately 90 degrees with respect to the scavenging volume obtained by adding the compression chamber 43 and the compression chamber 51 together. The helium compressed in the compression chamber 43 and the compression chamber 51 is cooled by the radiator 52 and is cooled to a temperature substantially equal to the temperature of the expansion chamber 55 by exchanging heat with the regenerator element 53a by the regenerator 53. The helium cooled by the regenerator 53 passes through the heat absorber 54 and flows into the expansion chamber 55, where it expands by the downward movement of the displacer 56 in FIG. 1 to generate a predetermined low temperature refrigeration. . The heat absorber 54 cools an object to be cooled (not shown) by refrigeration generated in the expansion chamber 55. Then, due to the upward movement of the displacer 56 in FIG. 1, the helium in the expansion chamber 55 passes through the heat absorber 54 and is heated by the regenerator element 53 a of the regenerator 53 and is compressed from the radiator 52 to the compression chamber 43. It flows into the chamber 51 and ends one cycle.

  As described above, the Stirling refrigerator 1 compresses helium by the reciprocating motion of the movable body 35 including the linear motor 20 to generate refrigeration at a predetermined low temperature. Since the linear motor 20 of this embodiment has high efficiency, the highly efficient Stirling refrigerator 1 can be provided.

  Further, since the linear motor 20 is small and light, and the Stirling refrigerator 1 is highly efficient, the Stirling refrigerator 1 is small and light.

  In addition, a magnetic flux in a certain direction (magnetization direction of the permanent magnet 33) flows through the inner yoke 31 or the permanent magnets 32 to 34 even though an alternating current is applied to the coils 26 and 27. The iron loss generated in 32 to 34 is reduced, and the temperature rise of the piston 36 and the piston guide 37 of the mover 30 is reduced. As a result, the wear amount of the non-lubricated sliding material piston 36 and piston guide 37 is reduced, and the durability of the Stirling refrigerator 1 is improved.

  FIG. 8 is a partial cross-sectional view of a modification of the mover 30 of the linear motor 20 of FIG. As shown in FIG. 8, the mover 121 of the linear motor 120 is different from the magnetic material holding member 31 in FIG. 1 in the shape of a holding member 122 made of a magnetic material. That is, the outer diameter of the holding member 122 is the same as the outer diameter of the holding member 31, and the inner diameter of the central portion 122b of the holding member 122 is the same as the inner diameter of the holding member 31. The inner diameter of 122 c is larger than the inner diameter of the holding member 31. In other words, the holding member 31 has a range approximately equal to the axial length of the magnetic pole piece 23a from the axial center of the permanent magnet 33 to the left side of the figure, and an approximate axis of the magnetic pole piece 23b from the axial center of the permanent magnet 33 to the right side of the figure. The thickness of the cylindrical portion with a range substantially equal to the length in the direction is thicker than the thickness of the cylindrical portions on both ends. This is the same as the cross-sectional area of the holding member 31 so as to avoid the magnetic saturation of the central portion 122b with a large amount of magnetic flux, and both the side portions 122a and 122c having a smaller magnetic flux amount than the central portion 122b have a larger inner diameter than the holding member 31. Thus, the minimum cross-sectional area that can avoid magnetic saturation is obtained. Accordingly, the mass of the mover 121 can be reduced, and the mover 121 can reciprocate at a high frequency.

  The Stirling refrigerator 1 is a displacer type Stirling refrigerator in which the working gas pressure acts on the front surface (upper surface in the drawing) and the rear surface (lower surface in the drawing) of the displacer 56, but the working gas pressure acts on the front surface instead of the displacer 56. Further, an expansion piston type Stirling refrigerator having an expansion piston (expansion side piston) on which a substantially constant working gas pressure acts may be provided on the back surface. In this case, the compression chamber 51 can be omitted, and the compression chamber is only the compression chamber 43. The expansion piston is connected to driving means such as a linear motor.

  Further, one permanent magnet 33 is provided as the mover 30 of the linear motor 20. However, next to the second permanent magnet in which the first permanent magnet, the third permanent magnet, and the second permanent magnet are sequentially disposed, for example, the third permanent magnet and the first permanent magnet are sequentially disposed. A plurality of third permanent magnets are provided. Accordingly, a plurality of permanent magnets 33 adjacent to the permanent magnet 32 and the permanent magnet 34 may be provided. In this case, if the number of permanent magnets 33 is an odd number, the number of permanent magnets 32 and the number of permanent magnets 34 is the same, one less than the number of permanent magnets 33. If the number of the permanent magnets 33 is an even number, the number of one of the permanent magnets 33 and 34 is equal to the number of the permanent magnets 33, and the number of the other permanent magnets is 1 than the number of the permanent magnets 33. There are many. A linear motor having a plurality of permanent magnets 33 can obtain a magnetic thrust substantially equal to a value obtained by multiplying the magnetic thrust of the linear motor 20 having one permanent magnet 33 by the number of permanent magnets 33. Therefore, in order to obtain a large magnetic thrust, a linear motor provided with a plurality of permanent magnets 33 is suitable.

  FIG. 9 is an explanatory diagram of a refrigeration generator of a Stirling pulse tube refrigerator. The displacer cylinder 57, the displacer 56, and the driving means 60 of the refrigeration generating unit 50 of FIG. 1 are arranged at the pulse tube 156, the gas piston 157 formed in the pulse tube 156, and the high temperature end 156b of the pulse tube 156, respectively. Instead of the phase adjusting means 160, the refrigeration generator 150 of the Stirling type pulse tube refrigerator 5 may be used. In this case, the Stirling type pulse tube refrigerator 5 (cold storage type refrigerator) communicates the refrigeration generator 150 and the same compressor 10 as in FIG.

  The refrigeration generating unit 150 includes a heat radiator 152 that is sequentially connected to a regenerator 153, a heat absorber 154, and a low temperature end 156 a of the pulse tube 156, and a high temperature end 156 b of the pulse tube 156 is connected to the phase adjusting means 160. Is done. A gas piston 157 indicated by an alternate long and short dash line is formed in the pulse tube 156. The gas piston 157 is an elastic piston whose mass is constant and volume is changed by the pressure of helium. Reciprocates. An expansion chamber 155 is formed on the low temperature end 156a side surrounded by the pulse tube 156 and the gas piston 157, and the expansion chamber 155 communicates with the heat absorber 154 through a pipe 158. The phase adjusting means 160 is composed of a buffer tank 161 and an inert tube 162 which is a long and narrow tube, and the volume of the buffer tank 161 and the flow of the inertance tube 162 so that the gas piston 157 advances a phase of about 90 degrees with respect to the movable body 35. Road resistance is adjusted. Thereby, the expansion chamber 155 acts in the same manner as the expansion chamber 55 of FIG. 1 and generates refrigeration at a predetermined temperature. Therefore, the Stirling pulse tube refrigerator 5 is highly efficient, small and light for the same reason as the Stirling refrigerator 1.

  FIG. 10 is an explanatory diagram of a Stirling refrigerator according to a second embodiment using the reciprocating drive mechanism of FIG. The same parts and the same parts as those of the Stirling refrigerator 1 in FIG. As shown in FIG. 10, the Stirling refrigerator 2 (cold storage type refrigerator) is configured by connecting a compression unit 80 and a refrigeration generating unit 50 shown in FIG. The compression unit 80 includes a pair of linear motors 20 and 20 (reciprocating drive mechanism) stator 21, a pair of movable bodies 35 and 35, and a cylinder 70. The movable body 35 includes a piston 36 and a piston guide 37 at both ends of the holding member 31 of the movable element 30. A pair of movable bodies 35 and 35 are inserted in the cylinder 70 so that reciprocation is possible so that each piston 36 and 36 may face. End plates 72 are hermetically fixed to the cylinder 70 at both ends of the cylinder body 71. A compression chamber 81 is formed by being surrounded by the cylinder 70 and the pair of movable bodies 35, 35, and the compression chamber 81 is connected to the compression chamber 51 of the refrigeration generating unit 50 via the pipe 11 communicating with the cylinder body 71. It communicates with the radiator 52. Other configurations are the same as the Stirling refrigerator 1 of FIG. The operation of the Stirling refrigerator 2 is the same as that of the Stirling refrigerator 1.

  In the Stirling refrigerator 2 of the second embodiment, the vibrations caused by the reciprocating motion of the movable body 35 are canceled out by arranging the pair of movable bodies 35 and 35 to face each other. In addition, the scavenging volume of the compression chamber 81 is larger than that of the compression chamber 43 (FIG. 1) of the Stirling refrigerator 1 of the first embodiment, so that the amount of refrigeration generated in the expansion chamber 55 is increased. Other effects are the same as the Stirling refrigerator 1.

  FIG. 11 is an explanatory diagram of a Stirling refrigerator using a reciprocating drive mechanism according to Embodiment 3 of the present invention. The same parts and the same parts as those of the Stirling refrigerator 1 in FIG. As shown in FIG. 11, the Stirling refrigerator 3 (cold storage type refrigerator) is configured by connecting a compression unit 110 and a refrigeration generating unit 50 shown in FIG. The compression unit 110 includes a pair of cases 101, 101, a pair of stators 21, 21 of a pair of linear motors 20, 20 (reciprocating drive mechanism) fixed to the inner peripheral surface of each case 101, 101, and a pair Movable bodies 135 and 135 and a pair of cylinders 140 and 140.

  The movable body 135 has a piston 136 fixed to the inner peripheral surface of the holding member 31 of the movable element 30. And a pair of movable bodies 135 and 135 oppose and are inserted in a pair of cylinders 140 and 140 so that a reciprocation is possible. Supporting tools 131 and 132 are fixed to both ends of the holding member 31, and the supporting tools 131 and 132 are inner circumferences of disk-shaped leaf springs 133 and 134 having elastic support means having a support function and an elastic function, for example, a slide. The outer sides of the leaf springs 133 and 134 are fixed to the inner periphery of the case 101. Accordingly, the pair of movable bodies 135 and 135 are supported so as to be able to reciprocate with a small gap with respect to the inner peripheral surfaces of the pair of cylinders 140 and 140.

  The cylinder 140 is open at both ends and includes a flange 140a at the center in the axial direction, and a pair of cases 101 and 101 are hermetically fixed to the outer peripheral side of the flange 140a. The compression chamber 143 is formed by being surrounded by the pair of movable bodies 135 and 135 and the cylinder 140, and the compression chamber 143 has a hole 140 b provided in the flange 140 a, the compression chamber 51 of the refrigeration generator 50 via the pipe 11, and heat dissipation. Communicating with the vessel 52. The conducting wires of the coils 26 and 27 of the stator 21 are connected to an airtight terminal (not shown). Other configurations are the same as the Stirling refrigerator 1 of FIG.

  The minute gap between the outer peripheral surface of the piston 136 and the inner peripheral surface of the cylinder 140 has a clearance sealing function for sealing helium in the compression chamber 143. The movable body 135 including the movable element 30 is composed of a spring composed of leaf springs 133 and 134, a magnetic spring of the linear motor 20, a spring composed of a helium gas spring acting on the front surface and the back surface of the movable body 135, and a movable body 135. A vibration system having a natural frequency is formed by the mass of the movable body 135 including the child 30, and the Stirling refrigerator 3 is operated in the vicinity of the natural frequency.

  The movable body 135 is supported by the leaf springs 133 and 134 so that the movable body 135 can reciprocate with a small gap with respect to the inner peripheral surface of the cylinder 140, so that the wear of the piston 136 is prevented and the durability of the Stirling refrigerator 3 is improved. To do. Moreover, the vibration which generate | occur | produces at the time of a driving | operation is reduced by arrange | positioning a pair of movable body 135,135 facing each other. Furthermore, since the spring constant of the synthetic spring is increased by the leaf springs 133 and 134, the Stirling refrigerator 3 can be operated at a high frequency, and the refrigerating capacity is increased. Other effects are the same as the Stirling refrigerator 3 of FIG.

  FIG. 12 is an explanatory diagram of a compressor according to Example 4 using the reciprocating drive mechanism of FIG. The same parts and the same parts as those of the Stirling refrigerator 1 in FIG. As shown in FIG. 12, the compressor 4 includes a stator 21 of the linear motor 20 (reciprocating drive mechanism) shown in FIG. 1, a movable body 35 having a movable element 30, and a movable body 35 inserted in a reciprocating manner. And a cylinder 90 including a suction valve 94 and a discharge valve 95, and a cylinder head 96. Then, for example, helium is filled as the working gas.

  The cylinder 90 includes a partition wall 92 and end plates 93 that are airtightly fixed to both ends of the cylinder body 91, and a suction valve 94 and a discharge valve 95 provided in holes 92 a and 92 b of the partition wall 92. A cylinder head 96 is airtightly attached to the partition wall 92, and a suction chamber 96 b and a discharge chamber 96 c are formed by the partition wall 96 a of the cylinder head 96. A compression chamber 97 is formed by being surrounded by the cylinder 90 and the front surface (the left end surface in the drawing) of the movable body 35. The compression chamber 97 is communicated with the suction chamber 96b and the discharge chamber 96c via the suction valve 94 and the discharge valve 95, respectively. .

  When an alternating current having the same amplitude and a phase of 180 degrees is applied to the coils 26 and 27 of the linear motor 20, the movable body 35 reciprocates. When the movable body 35 moves in the direction of the bottom dead center, the suction valve 94 is automatically opened by the differential pressure between the suction chamber 96b and the compression chamber 97, and helium is sucked into the compression chamber 97 from the suction chamber 96b. The sucked helium is compressed by the movement of the movable body 35 toward the top dead center, passes through the discharge valve 95 that is automatically opened by the pressure difference between the compression chamber 97 and the discharge chamber 96c, and enters the discharge chamber 96c. It flows in and is supplied from there.

  Since the compressor 4 compresses helium by reciprocating the movable body 35 with the linear motor 20 that is highly efficient and small and light, the highly efficient and small and lightweight compressor 4 can be obtained.

1, 2, 3 Stirling refrigerator (regenerator type refrigerator)
4 Compressor 5 Stirling type pulse tube refrigerator (regenerator type refrigerator)
20, 120 Reciprocating drive mechanism 21 Stator 21a, 21b Air gap (distance)
22a, 23a Pole piece (first pole piece)
23b, 24a Pole piece (second pole piece)
25 Outer yoke 26, 27 Coil 28, 29 Slot 30, 120 Movable member 31, 122 Holding member (inner yoke)
32 Permanent magnet (first permanent magnet)
33 Permanent magnet (third permanent magnet)
33a interval 34 permanent magnet (second permanent magnet)
36, 136 Piston 40, 70, 90, 140 Cylinder 43, 51, 81, 97, 143 Compression chamber 52, 152 Radiator 53, 153 Regenerator 54, 154 Heat absorber 55, 155 Expansion chamber 56 Displacer (expansion side piston)
57 Displacer cylinder (expansion side cylinder)
94 Suction valve 95 Discharge valve 156 Pulse tube 160 Phase adjusting means G1, G2a, G2b, G3 Gap (distance)
X axis

Claims (6)

The first permanent magnet magnetized in the radial direction on the outer peripheral surface N and the first permanent magnet are arranged coaxially with a predetermined interval in the axial direction of the first permanent magnet and magnetized in the opposite direction to the magnetization direction of the first permanent magnet. A mover comprising a second permanent magnet, and a third permanent magnet arranged in the interval from the second permanent magnet in the axial direction and magnetized in the direction of the first permanent magnet;
A pair of first magnetic pole pieces disposed at a predetermined distance on the outer peripheral side of the first permanent magnet and facing each other with a predetermined distance in the axial direction, and a predetermined distance on the outer peripheral side of the second permanent magnet A fixed structure composed of an outer yoke having a pair of second magnetic pole pieces arranged with a distance and facing each other with a predetermined distance in the axial direction, and a coil arranged in a slot formed in the outer yoke. With the child,
A piston coupled to the mover;
A reciprocating drive mechanism comprising: a cylinder in which the piston is inserted so as to be capable of reciprocating in the axial direction. The reciprocating drive mechanism according to claim 1, wherein a plurality of the third permanent magnets adjacent to the first permanent magnet and the second permanent magnet are provided. The reciprocating motion according to claim 1, wherein the first permanent magnet, the second permanent magnet, and the third permanent magnet are provided with a holding member made of a magnetic material on an inner peripheral surface. Drive mechanism. A compression chamber formed by the piston and the cylinder for compressing the working gas; a radiator for dissipating the compression heat of the working gas; a regenerator for exchanging heat with the working gas; a heat absorber for absorbing the working gas; The regenerative refrigerator according to at least one of claims 1 to 3, further comprising an expansion chamber in which gas expands. The regenerative refrigerator is a Stirling refrigerator in which the expansion chamber is formed by an expansion side cylinder and an expansion side piston inserted into the expansion side cylinder so as to be reciprocally movable, or a pulse tube and a high temperature side of the pulse tube 5. The regenerator according to claim 4, wherein the regenerator is a Stirling type pulse tube refrigerator having a phase adjusting means communicating with the Stirling type pulse tube refrigerator having the expansion chamber formed on a low temperature side of the pulse tube. Type refrigerator. A compression chamber formed by the piston and the cylinder and compressing the working gas;
A suction valve connected to the compression chamber and sucking a working fluid into the compression chamber;
4. The compressor according to claim 1, further comprising a discharge valve connected to the compression chamber and configured to compress the suctioned working gas and discharge the compressed working gas from the compression chamber. 5.

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