JP2010178484A - Linear electromagnetic driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear electromagnetic drive device that is easy to assemble, has high reliability and durability, is low in cost, and has high efficiency by freely reciprocating a mover.
A mover 10 is composed of a conductor 14 made of a non-magnetic material and having an inner peripheral surface and an outer peripheral surface and an electrically conductive material, and iron core pieces 12 and 13 provided on both end surfaces of the conductor 14. Further, a mover side yoke 2 made of a magnetic material is provided on the inner peripheral surface side of the iron core pieces 12 and 13, and a coil 24 in which a conducting wire is wound around the axis X of the mover 10, The stator 20 is composed of magnetic pole pieces 22 and 23 made of magnetic material and the stator side yoke 25 made of a magnetic material that connects the magnetic pole pieces 22 and 23, and the inner peripheral surface of the mover 10 and the stator 20. Are opposed to each other with predetermined gaps 51 and 52.
[Selection] Figure 1

Description

  The present invention relates to a linear electromagnetic drive device that reciprocates pistons of a regenerative refrigerator (for example, a Stirling refrigerator, a pulse tube refrigerator), a compressor, and the like by using electromagnetic force.

  As a conventional linear electromagnetic drive device, for example, a linear motor unit (linear electromagnetic drive device) of a linear compressor disclosed in Patent Document 1 is disclosed. This linear compressor has a magnetic path composed of a cylinder, a piston that is slidably supported along the axial direction at the same axis as the cylinder, a permanent magnet fixed to the piston, and a coil fixed to the cylinder. A linear motor unit that generates thrust, and the linear motor unit is disposed on the outer periphery of the piston, and a permanent magnet is sandwiched and fixed by a cylindrical holding member fixed to the piston and a cylindrical body concentric with the cylindrical holding member. The cylindrical holding member and the rod provided on the piston are coupled via a flange portion, and the flange portion is connected to the spring plate of the spring mechanism portion.

Japanese Patent No. 3499447

  However, according to Patent Document 1, since the linear motor unit uses a permanent magnet, a radial attractive force acts on the mover even when no current is passed through the coil. For this reason, a large radial load is always applied to the spring plate and liner (sliding bearing) provided to ensure the clearance between the mover and the stationary by the permanent magnet, and the durability of the spring plate and liner is reduced. As a result, the durability of the linear motor section is reduced.

  In addition, even when there is no electromagnetic current, the moving part has a permanent magnet attracting force, making it difficult to assemble, and initial failure related to securing clearance during assembly of the linear motor part is likely to occur, reducing reliability. There's a problem.

  Further, the linear motor unit requires a permanent magnet having a large holding force (for example, a neodymium-iron-boron permanent magnet), and the permanent magnet having a large holding force is expensive, so the cost of the linear motor unit increases. There's a problem.

  The present invention has been made in view of the above problems, and a linear electromagnetic drive device that is easy to assemble, has high reliability and durability, is inexpensive, and has high efficiency without using a permanent magnet. The purpose is to provide.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a non-magnetic material which is formed of an inner peripheral surface and an outer peripheral surface and a conductor of an electrically conductive material, and a magnetic material provided on both sides in the axial direction of the conductor. A mover having an iron core piece, a coil in which a conductive wire is wound around the axis of the mover, a pole piece made of a magnetic material provided on both sides of the coil in the axial direction, and the pole piece A stator having a stator-side yoke that is a magnetic material connected to each other, and a mover-side yoke that is a magnetic material provided on the inner peripheral surface side of the core piece, and an outer peripheral surface of the mover. A predetermined distance is provided between the stator and the inner surface of the stator facing the outer peripheral surface.

  The mover includes a piston inserted into the cylinder so as to be reciprocally movable.

  The pair of stators and movers are provided in a plurality of sets coaxially.

  In the first aspect of the invention, since the linear electromagnetic drive device does not have a permanent magnet, no magnetic force is generated between the stator and the mover when the coil is not energized. Therefore, the mover can be easily assembled to the stator with a predetermined gap without the outer peripheral surface of the mover coming into contact with the inner peripheral surface of the stator, and an initial failure related to the gap between the fixed member and the movable member is generated. This prevents the reliability of the linear electromagnetic drive device.

  In addition, since the linear electromagnetic drive device does not have a permanent magnet, the support member of the mover (for example, the flexure bearing) is not supported by a radial load that always acts, and the load is reduced by this radial load. The durability of the member is improved. As a result, the durability of the linear electromagnetic drive device is improved.

  Further, since the linear electromagnetic drive device does not use a permanent magnet and uses a non-magnetic material and a conductor of electrically conductive material instead of the permanent magnet, a low cost linear electromagnetic drive device can be provided.

  Further, in the invention described in claim 2, by using the linear electromagnetic drive device of the present invention to reciprocate the piston, for example, the linear electromagnetic drive device used for a regenerative refrigerator or a compressor is Assembling is easy, reliability and durability are improved, and cost is reduced.

  In the invention according to claim 3, a plurality of pairs of stators and movers are arranged in the reciprocating direction of the mover. As a result, compared to a linear electromagnetic drive device in which a set of a pair of stators and movers is provided, the linear electromagnetic drive device provided in a plurality of sets has an increased thrust, under the same stroke and the same supply current value. Since the copper loss of the coil is reduced, the efficiency is improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view of a linear electromagnetic device according to a first embodiment of the present invention, in which a linear electromagnetic driving device is applied to a compressor of a regenerative refrigerator such as a pulse tube refrigerator. FIG. 2 shows an AA cross section of FIG.

  As shown in FIG. 1, the compressor 100 includes a linear electromagnetic drive device 1, a motor case 3, and a compression unit 40. The linear electromagnetic drive device 1 includes a mover 10, a stator 20, and a mover side yoke 2.

  The mover 10 includes core pieces 12 and 13 formed by laminating a large number of laminated plates 11 made of a ring-shaped ferromagnetic material in the axis X direction of the mover 10, and a cylindrical nonmagnetic material (for example, aluminum, And a conductor 14 made of electrically conductive material. Iron core pieces 12 and 13 are fixed to both end faces of the conductor 14. Both surfaces of the laminated plate 11 and the inner peripheral surface of the conductor 14 are coated with an insulating film, whereby the laminated plate 11 laminated is electrically insulated from each other, and both end surfaces of the conductor 14 and the iron core pieces 12 and 13 are coated. Between the contact surface, the inner peripheral surface of the conductor 14, and the outer peripheral surface of the rod 32 are electrically insulated, and iron loss is reduced. The axis X is also the axis of the stator 20, the cylinder 41, and the motor case 3.

  The inner peripheral surface of the mover 10 is fixed to the outer peripheral surface of the rod 32. The rod 32 is provided with a hole 32a, and the cylindrical mover side yoke 2 made of a ferromagnetic material is inserted with a predetermined gap from the inner peripheral surface of the hole 32a.

  As shown in FIG. 2, the mover side yoke 2 is divided into mover side yoke pieces 2a and 2b in the direction of the axis X in order to suppress iron loss, and the divided surfaces of the mover side yoke pieces 2a and 2b are insulated. A film is applied and electrically insulated. The end portions of the mover side yoke element pieces 2 a and 2 b are fixed to the end plate portion 3 b of the motor case 3.

  The stator 20 includes a coil 24 in which a coated copper wire (conductive wire) is wound around an axis X with a predetermined distance from the outer peripheral surface of the mover 10, and cylindrical magnetic poles provided on both end surfaces of the coil 24. It is composed of pieces 22 and 23 and a stator side yoke 25 made of a ferromagnetic material fixed to the outer peripheral surfaces of the magnetic pole pieces 22 and 23, and the outer peripheral surface of the stator 20 is fixed to the inner peripheral surface of the motor case 3. . The magnetic pole pieces 22 and 23 are formed by laminating a large number of laminated plates 21 made of a ring-shaped ferromagnetic material in the direction of the axis X, and coat both surfaces of the magnetic pole pieces 22 and 23 with an insulating film. Thereby, the laminated plates 21 laminated are electrically insulated from each other, and iron loss is reduced. Further, both ends of a lead wire (not shown) of the coil 24 are connected to a hermetic seal provided in the motor case 3 and are connected to a power supply device (not shown) provided outside.

  The outer peripheral surface 10 a of the mover 10 is formed from the outer peripheral surfaces of the iron core pieces 12 and 13, and the inner peripheral surface 20 a (inner surface) of the stator 20 is formed from the inner peripheral surfaces of the magnetic pole pieces 22 and 23. When the coil 24 is not energized, the mover 10 is in a neutral position, and at this neutral position, the outer peripheral surface 10a of the mover 10 has a predetermined gap 51, 52 (distance) with respect to the inner peripheral surface 20a of the stator 20. Hold and meet. The outer diameter of the conductor 14 is smaller than the inner diameter of the stator 20 and does not hit the stator 20, and the inner diameter of the coil 24 is larger than the outer diameter of the mover 10 and does not have to hit the mover 10. In this embodiment, the outer diameter of the conductor 14 is the same as the outer diameter of the iron core pieces 12 and 13, and the inner diameter of the coil 24 is the same as the inner diameter of the magnetic pole pieces 22 and 23.

  The compression unit 40 includes a piston 31 and a rod-equipped piston 30 that is coaxially connected to the back surface 31b of the piston 31, a cylinder 41 having a flange 41a at one end and a cylinder head 41b at the other end. It consists of. The flange 41a is airtightly fixed to the end of the cylindrical portion 3a so that the inner peripheral surface of the cylinder 41 and the inner peripheral surface of the cylindrical portion 3a of the motor 3 are coaxial. The both ends of the rod 32 are fixed to the inner diameter side of a set of two flexure bearings 33, and the outer diameter side of the flexure bearing 33 is fixed to the inner peripheral surface of the motor case 3. The flexure bearing 33 is made of thin spring steel, has a disk shape, has a hole in the center, and is provided with a plurality of slits (not shown) on the disk surface so that the function of the spring and the rod 32 can be attached to the axis X. It has the function of a bearing that supports reciprocation in the direction. The flexure bearing 33 secures a predetermined gap between the inner peripheral surface of the stator 20 and the outer peripheral surface of the mover 10 and a predetermined minute gap between the inner peripheral surface of the piston 31. The gap between the stator 20 and the mover 10 forms a magnetic gap, and the minute gap between the piston 31 and the cylinder 41 forms a clearance seal. Further, the springs of the four flexure bearings 33, the magnetic spring generated when the movable element 10 and the stator 20 are energized, and the gas spring by the working gas (for example, helium) acting on the front surface 31a and the back surface 31b of the piston. And a total mass of the mover 10 and the piston 30 with the rod form a vibration system having a resonance frequency.

  A compression chamber 42 is formed by being surrounded by the cylinder 41 and the piston 31. The compression chamber 42 is communicated with a flow path 41c provided in the cylinder head 41b and a refrigeration generator (not shown) via a pipe 43. Further, on the back surface 31 b side of the piston 31, the buffer chamber 4 is formed by the piston 31, the motor case 3, and the cylinder 41, and the volume of the buffer chamber 4 is sufficiently larger than the scavenging volume of the compression chamber 42 (for example, the scavenging volume of the scavenging volume). About 15 times).

  The motor case 3 may be made of a ferromagnetic material so that the cylindrical portion 3a of the motor case 3 may be a stator side yoke without providing the stator side yoke 25. Alternatively, the outer diameters of the magnetic pole pieces 22 and 23 may be increased to be equal to the inner diameter of the motor case 3, and a stator yoke may be provided between the opposing faces of the magnetic pole pieces 22 and 23.

  The pole pieces 22 and 23 are one cylindrical body formed by laminating the laminated plates 21. The magnetic pole pieces 22 and 23 are configured by combining column bodies obtained by dividing the cylindrical body in the radial direction (for example, divided into four parts). Also good. By dividing, the assembly of the coil 24 to the stator 20 is facilitated.

  1 is fixed to the inner peripheral surface of the motor case 3, the stator 20 may be fixed to the outer peripheral surface of the motor case 3.

  Further, in the stator 20 of the linear electromagnetic drive device 1, one coil 24 is provided between the pole pieces 22 and 23, but a plurality of coils 24 may be provided in the axis X direction. Similarly, one conductor 14 is disposed between the core pieces 12 and 13, but a plurality of conductors 14 may be disposed in the direction of the axis X.

  Next, the operation and effect of the linear electromagnetic drive device 1 will be described. When the supply current of the coil 24 is in the vicinity of the above-described resonance frequency, the amplitude of the reciprocating motion of the movable body 10 increases, and the linear electromagnetic driving device 1 operates efficiently. In this case, the phase of the reciprocating displacement of the mover 10 is delayed by approximately 90 degrees from the phase of the supply current. Then, a sinusoidal alternating current near the resonance frequency is supplied to the coil 24. Immediately after the supply, when the motor case 3 is tapped, the mover 10 moves slightly from the neutral position, vibrates and immediately reciprocates with a predetermined amplitude. It operates as follows.

  FIG. 3 shows a waveform of a sinusoidal alternating current I supplied to the coil 24, a waveform of the differential dI / dt of the coil current I at time t, and a displacement waveform of the mover 10. FIG. FIG. 4 is a partial cross-sectional explanatory view of the operation of the linear electromagnetic device 1. FIG. 5 is a diagram showing lines of magnetic force generated by the current of the coil 24 generated in the gaps 51 and 52 and the induced current of the conductor 14. FIG. 6 is a diagram showing magnetic field lines obtained by combining the magnetic field lines in FIG. 4 to 6, the symbol of the dot in the circle and the symbol of the cross in the circle indicate the direction, the symbol of the dot in the circle indicates the direction of the front from the back of the page, and the symbol of the cross in the circle indicates the direction of the page. The direction from the front to the back is shown. A two-dot chain line indicates a neutral position of the front surface 31 a of the piston 31. 5 and 6, the solid and thin arrow lines of the gaps 51 and 52 indicate magnetic lines of force, and the arrows indicate the flow direction of the magnetic lines of force. The gap 51 is a gap formed between the magnetic pole piece 22 and the iron core piece 12, the gap 52 is a gap formed in the gap between the magnetic pole piece 23 and the iron core piece 13, and the magnetic flux passes through the gaps 51 and 52. A magnetic gap is formed.

  As shown in FIG. 3, when the mover 10 is located at the neutral position a and moves toward the top dead center c, the coil current is a positive maximum current Ia and the current time derivative (hereinafter, current derivative) dIa / dt is 0 (current). In this state, there is no change in the magnetic flux Φb. The maximum current Ia generates a closed loop maximum magnetic flux Φa (FIG. 4A), and the maximum magnetic flux Φa causes the maximum density magnetic field lines Ma1 indicated by the solid lines of the arrows to be substantially uniform over substantially the entire axis X direction of the gaps 51 and 52, respectively. Ma2 (FIG. 5A) is generated. Since the current differential dIa / dt is 0, no current is induced in the conductor 14, and therefore no magnetic field lines due to the magnetic flux generated by the induced current are generated in the gaps 51 and 52 (FIG. 5A). Therefore, the magnetic lines of force Ma1 and Ma2 and the magnetic lines of force Pa1 and Pa2 obtained by synthesizing the magnetic lines of force based on the induced current become the magnetic lines of force Ma1 and Ma2 (FIG. 6A). Since the combined magnetic lines of force Pa1 and Pa2 are substantially uniform over substantially the entire axis X direction, no magnetic force Fm acting on the movable body 10 is generated, and the above-described combined spring force Ks is also generated by the mover 10. Since it is located in the neutral position, it is substantially zero. Therefore, the movement state of the mover 10 is continued, and the mover 10 moves in the B direction, that is, the top dead center c direction (FIGS. 4A and 6A). As shown in FIG. 4, the magnetic flux Φa and the magnetic fluxes Φb, Φe, Ψb, Ψc, and Ψd described below are sequentially provided with the magnetic pole piece 22, the gap 51, the iron core piece 12, the mover side yoke 2, and the iron core piece 13. , Passing through the gap 52, the magnetic pole piece 23, and the stator side yoke 25, returning to the magnetic pole piece 22 and forming a closed loop.

  As shown in FIG. 3, when the mover 10 is located at a point b between the neutral position a and the top dead center c and moves toward the top dead center c, the coil current is positive at Ib, the current differential dIb / dt is negative, and the magnetic flux Φb is in a decreasing state, and a closed-loop magnetic flux Φb (FIG. 4B) is generated by the coil current Ib. Magnetic flux lines Φb generate magnetic field lines Mb1 and Mb2 (FIG. 5B) indicated by solid lines of arrows substantially uniformly over substantially the entire axis X direction of the gaps 51 and 52, respectively, and the current Ib flows in the conductor 14 by the reduced magnetic flux Φb. A current in the same direction is induced. This induced current generates a closed-loop magnetic flux Ψb in the same direction as the magnetic flux Φb. The magnetic flux Ψb causes a magnetic field line Nb1 indicated by a thin arrow line around the end face of the conductor 14 in the gap 51 and around the end face of the coil 24 in the gap 52. , Nb2 (FIG. 5B) is generated. Then, magnetic fluxes Pb1 and Pb2 (FIG. 6B) obtained by synthesizing the magnetic lines of force Nb1 and Nb2 are generated in the gaps 51 and 52. Since the direction of the magnetic force lines Mb1 and Mb2 and the magnetic force lines Nb1 and Nb2 are the same, the combined magnetic fluxes Pb1 and Pb2 are dense on the end face side of the conductor 14 and the end face side of the coil 24 and sparse on the far side in the axis X direction from both end faces. The magnetic force Fm in the direction toward the neutral position acts on the mover 10 so that the density is equalized. The movable body 10 moving toward the top dead center c is decelerated by the magnetic force Fm and the combined spring force Fs in the direction toward the neutral position (FIGS. 4B and 6B).

  When the mover 10 reaches the top dead center c while being decelerated, the speed and current Ic of the movable body 10 are 0, the current differential dIc / dt is negative, and the absolute value is maximum (FIG. 3). Since the current Ic is 0, no magnetic flux is generated by the current Ic (FIG. 4C), and no magnetic field lines based on the current Ic are generated in the gaps 51 and 52 (FIG. 5C). Further, since the current differential dIc / dt is negative and the absolute value is maximum, a maximum induced current in the same direction as the coil current Ib is generated in the conductor 14. This induced current generates a closed loop maximum magnetic flux Ψc, and magnetic field lines Nc1 and Nc2 with the maximum density due to the maximum magnetic flux Ψc are generated near the end face of the conductor 14 in the gap 51 and in the vicinity of the end face of the coil 24 in the gap 52 (FIG. 5). (C)). The combined magnetic lines of force Pc1 and Pc2 generated in the gap 51 and the gap 52 become the magnetic lines of force Nc1 and Nc2 (FIG. 6C), but the magnetic force Fm due to the magnetic lines of force Nc1 and Nc2 is not generated, and the movable body 10 is neutral. The combined spring force Fs in the direction toward the position acts, and the movable element 10 starts to move toward the neutral position e (FIGS. 4C and 6C).

  As shown in FIG. 3, when the mover 10 is located at a point d between the top dead center c and the neutral position e and moves toward the neutral position e, the coil current Id and the current differential dId / dt are negative, and the magnetic flux Φd is In the increased state, the coil current Id generates a magnetic flux Φd (FIG. 4D) in the opposite direction to the magnetic fluxes Φa and Φb. Magnetic flux Φd generates magnetic lines of force Md1 and Md2 (FIG. 5D) indicated by solid lines of arrows approximately uniformly over substantially the whole of the gaps 51 and 52 in the direction of the axis X, and the current Id is generated in the conductor 14 by the increased magnetic flux Φd. In contrast, a current in the opposite direction is induced. This induced current generates a magnetic flux ψd (FIG. 4 (d)) in the opposite direction to the magnetic flux Φd. The magnetic flux ψd causes the arrows 51 around the end face of the conductor 14 in the gap 51 and around the end face of the coil 24 in the gap 52. Magnetic field lines Nd1 and Nd2 (FIG. 5B) indicated by thin lines are generated. Magnetic field lines Pd1 and Pd2 (FIG. 6 (d)) obtained by combining the magnetic field lines Md1 and Md2 and the magnetic field lines Nd1 and Nd2 are generated in the gaps 51 and 52. Since the magnetic lines Nb1 and Nb2 are in opposite directions to the magnetic lines Mb1 and Mb2, the end face side of the conductor 14 and the end face side of the coil 24 are sparse, and the distant side in the axis X direction is dense from both end faces. Magnetic force Fm in the direction toward the neutral position acts on the mover 10 so as to be uniform. Then, the movable body 10 is moved toward the C direction, that is, toward the neutral position e by the magnetic force Fm and the combined spring force Fs in the direction toward the neutral position, and the movable body 10 is accelerated (FIG. 4D). 6 (d)).

  As shown in FIG. 3, when the mover 10 reaches the neutral position e, the coil current is negative and the absolute value is the maximum current Ie, the current differential dIe / dt is 0 (the current change is 0), and the magnetic flux Φe. No increase or decrease. The coil current Ie generates a maximum magnetic flux Φe (FIG. 4 (e)), and the maximum magnetic flux Φe causes the maximum density magnetic field lines Me1 and Me2 (shown by solid lines of arrows) to be substantially uniform over substantially the entire axis X direction of the gaps 51 and 52, respectively. FIG. 5 (e)) results. Since the current differential dIe / dt is 0, no current is induced in the conductor 14, and no magnetic force lines are generated in the gaps 51 and 52 due to the magnetic flux generated by the induced current. Therefore, the combined magnetic lines of force Pe1 and Pe2 become magnetic lines of force Me1 and Me2 (FIG. 6E). Since the combined magnetic lines Pe1 and Pe2 are substantially uniform over substantially the entire direction of the axis X, the magnetic force Fm acting on the movable body 10 is not generated, and the combined spring force Fs is also substantially zero. Therefore, the mover 10 moves in the direction of the bottom dead center g while the mover 10 continues to move (FIGS. 4E and 6E).

  The series of operations described above is a half cycle in which the movable body 10 reaches the top dead center c from the neutral position a and then returns to the neutral position e again. The half cycle in which the movable body 10 reaches the bottom dead center g from the neutral position e via the point f and then returns to the neutral position i again through the point h is performed in the same manner as the above-described series of half cycle operations. The operation of one cycle of the mover 10 is completed.

  As described above, when a sinusoidal alternating current is applied to the coil 24, the magnetic lines of force in the gaps 51 and 52 are sparse, and a magnetic force is generated to move the mover 10 so as to equalize the sparse / dense. The combined spring force and the force of the mover 10 act on each other, and the piston 31 integrated with the mover 10 reciprocates via the rod 32. As the piston 31 reciprocates, the compression chamber 42 compresses and expands helium. The compressed helium flows into the refrigeration generator (not shown) through the flow path 41c and the pipe 43, and expands there to generate refrigeration. The expanded helium flows again into the compression chamber 42 by the expansion of the compression chamber 42 through the pipe 43 and the flow path 41c, and one cycle of the compressor 100 is completed.

  With the above operation, the following effects are produced. That is, since the linear electromagnetic drive device 1 does not have a permanent magnet, no magnetic attractive force is generated between the stator 10 and the mover 20 when the coil is not energized. Accordingly, the outer peripheral surface of the mover 10 can be easily assembled with a predetermined gap without coming into contact with the inner peripheral surface of the stator 20, and the contact between the outer peripheral surface 10 a of the mover 10 and the inner peripheral surface 20 a of the stator 20. In addition, the initial failure due to the turning of the piston 31 and the cylinder 41 and the turning of the mover side yoke 2 and the hole 32a of the rod 32 can be prevented, and the reliability of the linear electromagnetic drive device 1 is improved.

  Further, since the linear electromagnetic drive device 1 does not have a permanent magnet, the radial load of the permanent magnet does not always act on the flexure bearing 33, and the load acting on the flexure bearing 33 is reduced by this radial load. Is done. As a result, the durability of the flexure bearing 33 is improved, and accordingly, the durability of the linear electromagnetic drive device 1 is improved.

  Further, the linear electromagnetic drive device 1 does not use a permanent magnet (for example, a neodymium-iron-boron permanent magnet), and is a non-magnetic material instead of a permanent magnet and an electrically conductive material (for example, copper, aluminum, etc.). Therefore, the linear electromagnetic drive device 1 can be provided at a low cost.

  Moreover, the linear electromagnetic drive device 1 forms the compression chamber 42 with the cylinder 41 and the piston 31, and reciprocates the piston 31, compresses helium, and supplies it to the refrigeration generating part of the regenerator type refrigerator. Thereby, the linear electromagnetic drive device 1 of the compressor 100 for the regenerator type refrigerator is easy to assemble, and the reliability and durability are improved and the cost is reduced.

  Furthermore, since the movable element 10 integrated with the piston 30 with the rod forms a vibration system having a resonance frequency of spring and mass, by operating the coil 24 with a current near the resonance frequency, The efficiency of the linear electromagnetic drive device 1 is improved and the efficiency of the compressor 100 is also improved.

(Second Embodiment)
FIG. 7 is a sectional view of a linear electromagnetic device according to the second embodiment of the present invention, in which the linear electromagnetic driving device is applied to a compressor of a regenerative refrigerator such as a pulse tube refrigerator. The same reference numerals as those in FIG. 1 denote the same parts and the same parts as those in FIG. As shown in FIG. 7, the compressor 200 includes a linear electromagnetic drive device 5, a motor case 3, and a compression unit 40. The linear electromagnetic drive device 5 includes a pair of movers and stators, that is, a mover 110 and a stator 120, a mover 210 and a stator 220, a mover 310 and a stator 320, and a mover side. The yoke 2 is configured.

  The mover 110 is formed by laminating a plurality of laminated plates 11 made of a ring-shaped ferromagnetic material fixed to both ends of the conductor 114 and a conductor 114 made of a cylindrical non-magnetic material and electrically conductive material. It is comprised from the comprised iron core piece 112,113. Both surfaces of the laminate 11 are coated with an insulating film. Similar to the mover 110, the mover 210 includes a conductor 214 and iron core pieces 212 and 213, and the mover 310 includes a conductor 314 and iron core pieces 312 and 313. The movers 110, 210, and 310 are sequentially stacked in the direction of the axis X (the axes of the movers 110, 210, and 310) and fixed to the rod 32. Both end surfaces and inner peripheral surfaces of the conductors 114, 214, and 314 are electrically insulated. A cylindrical mover-side yoke 2 made of a ferromagnetic material is inserted into the hole 32a of the rod 32 with a predetermined gap with respect to the inner peripheral surface of the hole 32a, and the inside of the movers 110, 210, 310 is inserted. The peripheral surface surrounds the outer peripheral surface of the mover side yoke 2 with the rod 32 interposed.

  The stator 120 includes a coil 124 in which a coated copper wire (conductive wire) is wound around the axis X at a predetermined distance from the outer peripheral surface of the mover 110, and magnetic pole pieces 122 provided on both end surfaces of the coil 124. 123, a magnetic pole piece 122, and a stator side yoke 125 made of a ferromagnetic material fixed to the outer peripheral end face of 123. The pole pieces 122 and 123 are configured by laminating a large number of laminated plates 21 made of a ring-shaped ferromagnetic material in the axis X direction, and both sides of the pole pieces 122 and 123 are coated with an insulating film. Similar to the stator 120, the stator 220 includes a coil 224, magnetic pole pieces 222 and 223, and a stator side yoke 225, and the stator 320 includes a coil 324, magnetic pole pieces 322 and 323, and a stator And a side yoke 325. The stators 120, 220, and 320 are stacked in the direction of the axis X and fixed to the inner peripheral surface of the motor case 3. In the neutral position, the outer peripheral surfaces 110a, 210a, 310a of the movers 110, 210, 310 have predetermined gaps with the inner peripheral surfaces 120a, 220a, 320a of the stators 120, 220, 320, respectively. Face to face. This gap forms a magnetic gap.

  Each outer peripheral surface 110a, 210a, 310a of the mover 110, 210, 310 is formed in the same manner as the outer peripheral surface 10a of the mover 1 in FIG. The inner peripheral surfaces 120a, 220a, and 320a of the stators 120, 220, and 320 are formed in the same manner as the inner peripheral surface 20a of the stator 20 in FIG. Other configurations are the same as those of the compressor 100 of FIG.

  Next, the operation and effect of the linear electromagnetic drive device 5 will be described. The operation of each pair of mover 110 and stator 120, mover 210 and stator 220, mover 310 and stator 320 is the same as the operation of the pair of mover 10 and stator 20 in FIG. . The coils 124 and 324 supply an alternating current having the same phase and the same amplitude from a power supply device (not shown), and the coil 224 has the same amplitude as the current of the coil 124 and a phase of 180 with respect to the current of the coil 124. Supply a current that is off. Thus, the magnetic flux generated by the coil 124 and the conductor 114 and the magnetic flux generated by the coil 224 and the conductor 214 respectively flow in the same direction without canceling each other in the iron core pieces 113 and 212 and the magnetic pole pieces 123 and 222. Similarly, the magnetic flux generated by the coil 224 and the conductor 214 and the magnetic flux generated by the coil 324 and the conductor 314, respectively, flow in the same direction without canceling out in the iron core pieces 213 and 312 and the magnetic pole pieces 223 and 322. Therefore, the linear electromagnetic drive device 5 is equivalent to the case where three sets of the linear electromagnetic drive devices 1 of FIG. 1 are provided, and therefore, a thrust three times that of the linear electromagnetic drive device 1 can be obtained.

  In addition, a linear electromagnetic driving device is used under the condition that the supply current value from the power supply device (not shown) is the same and the coil 24 (FIG. 1) and the coils 124, 224, and 324 have the same wire diameter, number of turns, and total length. Since the copper loss of 5 is one third of that of the linear electromagnetic drive device 1, the efficiency of the linear electromagnetic drive device 5 is improved. Other effects are the same as those of the linear electromagnetic drive device 1 of FIG.

1 is a cross-sectional view of a linear electromagnetic device according to a first embodiment of the present invention. It is AA sectional drawing of FIG. It is a figure which shows the electric current waveform which supplies with electricity to the coil of a linear electromagnetic drive device. FIG. 2 is a partial cross-sectional explanatory view of the operation of the linear electromagnetic device in FIG. 1. It is a figure which shows each magnetic force line of the gap | interval produced by the electric current of the coil of FIG. 1, and the induced current of a conductor. It is a figure which shows the magnetic force line which synthesize | combined each magnetic force line which arises in the gap | interval of FIG. It is sectional drawing of the linear electromagnetic device which concerns on 2nd Embodiment of this invention.

1, 5 Linear type electromagnetic drive device 2 Movable element side yoke 10, 110, 210, 310 Movable element 10a, 110a, 210a, 310a Outer peripheral surface 12, 13, 112, 113, 212, 213, 312, 313 Iron core piece 14, 114, 214, 314 Conductor 20, 120, 220, 310 Stator 20a, 120a, 220a, 320a Inner peripheral surface (inner surface)
22, 23, 122, 123, 222, 223, 322, 323 Magnetic pole piece 24, 124, 224, 324 Coil 25, 125, 225, 325 Stator side yoke 31 Piston 41 Cylinder 51, 52 Gap (distance)
X axis

Claims (3)

A mover having an inner peripheral surface and an outer peripheral surface, a nonmagnetic material and a conductor of electrically conductive material, and iron core pieces that are magnetic materials provided on both sides in the axial direction of the conductor;
A coil in which a conducting wire is wound around the axis of the mover; a magnetic pole piece that is a magnetic material provided on both sides of the coil in the axial direction; and a stator side yoke that is a magnetic material that connects the magnetic pole pieces to each other; A stator having
A mover side yoke that is a magnetic material provided on the inner peripheral surface side of the iron core piece, and
A linear electromagnetic driving device having a predetermined distance between an outer peripheral surface of the mover and an inner surface of the stator facing the outer peripheral surface. 2. The linear electromagnetic drive device according to claim 1, wherein the mover includes a piston inserted into a cylinder so as to be reciprocally movable. The linear electromagnetic drive device according to claim 1, wherein a plurality of pairs of the stator and the movable element are provided coaxially.

Images