JP2007089344A - Linear electromagnetic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an easily assemblable yet high-reliability piston, while reducing the sections that require high machining accuracy. <P>SOLUTION: The linear electromagnetic device has a cylinder 7, a piston 15 inserted slidably into the cylinder 7, a driving permanent magnet 17 and a magnetically conductive body 18, respectively fixed to the piston 15 itself, and a stator 21 having an electromagnetic coil 19 and an electromagnetic core 20, respectively arranged facing the outer peripheral side of the permanent magnet 17. The drive force for reciprocating the piston 15 is generated, by generating an alternating magnetic field, by allowing an AC current to flow into the electromagnetic coil 19. In this way, the piston 15 itself becomes a movable member of a linear motor, by incorporating driving components into the inside of the piston 15 itself. Consequently, it is possible to miniaturize the shape of the linear electromagnetic device, while simplifying the structure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is composed of a combination of a piston and a cylinder, such as a compressor or a Stirling refrigerator, and has a primary side that generates a magnetic field and a secondary side that moves linearly thereby, or linearly moves The present invention relates to an electromagnetic device such as a linear generator having a primary side that performs power generation and a secondary side that generates power.

  Conventionally, a casing having a cylindrical portion formed in a substantially cylindrical shape, a cylinder that is coaxially inserted into the cylindrical portion of the casing, a displacer that is slidably inserted into the front end side of the cylinder, A mover having a piston slidably inserted inside the base end side of the cylinder, a permanent magnet disposed outside the base end side of the cylinder and fixed to the base end of the piston via a frame, and the permanent A device including a driving device having an electromagnetic coil and a stator having an electromagnetic core disposed opposite to each other on the outer peripheral side of a magnet is known (for example, Patent Document 1).

  As shown in the cross-sectional view of the example of the free piston type Stirling refrigerator shown in FIG. 4, such a conventional technique has a piston 102 on the inside of a fixed body such as the cylinder 101 with a slight gap therebetween or in contact therewith. A movable body such as a linear motor is disposed and driven by a driving power source such as a linear motor. In other words, the piston 102 and a power source such as a linear motor for driving the piston 102 have different structures. This linear motor includes an outer stator 104 having a winding (electromagnetic coil) 103, an inner stator 105, and a mover 107 having a magnet (permanent magnet) 106. In addition, it can also be set as a generator by switching input and output with the same structure.

In such a case, when an alternating current is passed through the winding (electromagnetic coil) 103, an alternating magnetic field is generated from the winding (electromagnetic coil) 103 and concentrated at the electromagnetic core 108 of the outer stator 104, The alternating magnetic field generates a force that reciprocates the permanent magnet 106 in the axial direction. By this force, the piston 102 to which the permanent magnet 106 is fixed reciprocates in the cylinder 101 in the axial direction. When the piston 102 moves in a direction approaching the displacer 109, the gas in the compression chamber C formed between the piston 102 and the displacer 109 is compressed, and the communication hole 110, the exhaust heat fin 111, The displacer 109 reaches the piston 102 by passing through the regenerator 112, the heat-absorbing fin 113, and the gap 114 to reach the expansion chamber E formed between the tip of the displacer 109 and the tip portion 1 16 of the cylindrical portion 115. On the other hand, it is pushed down with a predetermined phase difference. On the other hand, when the piston 102 moves away from the displacer 109, the inside of the compression chamber C becomes negative pressure, and the gas in the expansion chamber E passes from the expansion chamber E to the gap 114, the heat absorption fin 113, and the regeneration. The displacer 109 is pulled up with a predetermined phase difference with respect to the piston 102 by returning to the compression chamber C through the vessel 112, the exhaust heat fin 111, and the communication hole 110. In such a process, a reversible cycle consisting of two isothermal changes and an equal volume change is performed, so that the vicinity of the expansion chamber E becomes low temperature, while the vicinity of the compression chamber C becomes high temperature.
JP 2005-42594 A

  The prior art has the following problems. First, since the piston 102 and the movable element 107 for driving the piston 102 are different structures, the shape is large. That is, there is an inner stator 105 (inner core) of a linear motor that reciprocates outside the piston 102 and the cylinder 101, and the movable element 107 including the magnet (permanent magnet) 106 is arranged on the outer side. As a result, the entire Stirling refrigerator has become large, which has been an obstacle to downsizing. Further, since the piston 102 disposed inside the cylinder 101 is driven by a linear motor disposed outside the cylinder 101, the driving mechanism is complicated. Furthermore, the narrow gap of the linear motor, that is, the gap between the magnet (permanent magnet) 106 and the outer stator 104 and the gap between the magnet (permanent magnet) 106 and the inner stator 105 are expensive. Precise machining was necessary.

  Therefore, the present invention provides a linear electromagnetic device having a piston that has a simple structure, reduces the number of parts that require high machining accuracy, is easy to assemble, and is highly reliable. Objective.

  The invention of claim 1 includes a cylinder, a piston slidably inserted into the cylinder, a permanent magnet fixed to the piston, an electromagnetic coil and an electromagnetic core disposed opposite to the outer peripheral side of the permanent magnet. A linear electromagnetic device having a stator, wherein the piston itself includes at least one permanent magnet or a magnetic conductor.

  The invention according to claim 2 is the linear electromagnetic device according to claim 1, wherein the cylinder is made of synthetic resin.

  According to a third aspect of the present invention, the stator is disposed so as to cover the outer side of the piston, and the whole or inner surface of the stator is integrally molded with the cylinder by a synthetic resin. It is a linear electromagnetic device of description.

  According to the first aspect of the present invention, the structure can be simplified and the size can be reduced by incorporating the permanent magnets, the magnetic conductors and the like constituting the linear electromagnetic device into the piston itself.

  According to the invention of claim 2, since the cylinder between the stator and the permanent magnet or the magnetic conducting body is a synthetic resin that transmits the lines of magnetic force, the lines of magnetic force are not blocked by the cylinder. The electromagnetic device can be operated efficiently.

  According to the invention of claim 3, not only can the number of parts and the number of assembling steps around the cylinder and the stator be reduced, but also the inner surface of the electromagnetic core of the stator and the permanent magnet or magnetic conductor of the piston Thus, the linear electromagnetic device can be operated efficiently.

  Preferred embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below do not limit the contents of the present invention described in the claims. In addition, all the configurations described below are not necessarily essential requirements of the present invention.

  FIG. 1 shows a first embodiment. In the following embodiments, a linear motor will be described as an example of a linear electromagnetic device. Reference numeral 1 denotes a casing composed of a cylindrical portion 2 and a body portion 3 formed in a substantially cylindrical shape. The cylindrical portion 2 is made of stainless steel or the like, and a base portion 4, an intermediate portion 5 and a tip portion 6 are integrally formed.

  Inside the cylindrical part 2, a cylinder 7 extending to the inside of the body part 3 is provided so as to be coaxially inserted with respect to the cylindrical part 2. The cylinder 7 is made of, for example, a synthetic resin such as PPS (Polyphenylene Sulfide) containing carbon short fibers as a reinforcing material, and has a sliding surface on the inner surface and is made of a nonmagnetic metal. A thin sliding cylinder 7A is inserted. A displacer 8 is accommodated inside the cylinder 7 so as to be slidable in the axial direction. An expansion chamber E is formed between the tip of the displacer 8 and the tip 6 of the cylindrical portion 2, and the inside and outside of the tip of the cylinder 7 communicate with each other through a gap 9. In the intermediate portion 5, a regenerator 10 is provided between the inner periphery of the cylindrical portion 2 and the outer periphery of the cylinder 7, and a communication hole that communicates the inside and outside of the cylinder 7 in the base portion 4. 11 is formed in the cylinder 7 itself. Further, a heat-absorbing fin 12 is provided between the inner periphery of the distal end portion 6 of the cylindrical portion 2 and the outer periphery of the distal end of the cylinder 7, and the cylindrical portion 2 is interposed between the regenerator 10 and the communication hole 11. An exhaust heat fin 13 is provided between the inner periphery of the cylinder 7 and the outer periphery of the cylinder 7. A path 14 is formed from the inner tip of the cylinder 7 to the compression chamber C in the cylinder 7 through the gap 9, the heat absorbing fin 12, the regenerator 10, the exhaust heat fin 13, and the communication hole 11.

  Further, a piston 15 is accommodated in the body portion 3 on the inner side of the base portion side of the cylinder 7 so as to be slidable in the axial direction. The piston 15 has a piston main body 15 </ b> A that slides in the cylinder 7, and a base end portion of the piston 15 is coaxially connected to the drive device 16. The piston body 15A is made of, for example, a synthetic resin such as PPS containing molybdenum disulfide as a lubricant and carbon short fibers as a reinforcing material. The driving device 16 is fixed to the inner peripheral surface of the piston main body 15A, and is fixed to the inner peripheral surface of the piston main body 15A, and on both axial sides and the inner peripheral side of the permanent magnet 17. The magnetic conductor 18 is arranged, and a stator 21 having an annular electromagnetic coil 19 and an electromagnetic core 20 provided in the vicinity of the outer peripheral side of the permanent magnet 17. In addition, the base end side of the cylinder 7 facing the inner surface of the stator 21 is formed to be thinner than the other portions, whereby the inner surface of the electromagnetic core 20 and the permanent magnet 17 are The distance from the outer periphery is shortened.

  The piston 15 is connected to a first leaf spring 23 for controlling the operation of the piston 15. Further, one end of a rod 24 for controlling the operation of the display sensor 8 is connected to the base end side of the display sensor 8, and a second leaf spring 25 is connected to the other end of the rod 24. It is connected. The rod 24 extends through the piston 15. The pair of leaf springs 23 and 25 are disposed outside the base end side of the cylinder 7 in the body portion 3 and are second leaf springs 25 than the first leaf springs 23. Is disposed at a position away from the base end side of the cylinder 7.

  A flange-like mount 27 that projects coaxially with the cylinder 7 is formed integrally with the cylinder 7 on the outer peripheral surface of the intermediate portion of the cylinder 7, and the drive device 16 is attached to the mount 27. It is formed so that one end of the constituting electromagnetic core 20 abuts. Further, for example, a ring-shaped fixing member 28 is in contact with the other end of the electromagnetic core 20. The fixing member 28 is formed by casting such as die casting using a metal such as aluminum having better thermal conductivity than the electromagnetic core 20. Then, the electromagnetic core 20 is sandwiched between the mount 27 and the fixing member 28 and tightened with, for example, a screw (not shown), so that the electromagnetic coil integrated with the electromagnetic core 20 is eventually formed. 19 is fixed to the mount 27. Further, a plurality of connecting arm portions 30 project from the mount 27 substantially parallel to the axial direction of the cylinder 7. The connecting arm 30 is formed integrally with the mount 27 at the base end. The first plate spring 23 is screwed to the tip of the connecting arm 30 by a spacer 31, and the second plate spring 25 is screwed to the spacer 31 by a screw 32. Screwed.

  With this configuration, when an alternating current is passed through the electromagnetic coil 19, an alternating magnetic field is generated from the electromagnetic coil 19 and concentrated by the electromagnetic core 20, and the alternating magnet reciprocates the permanent magnet 22 in the axial direction. The force to make arises. A non-magnetic metal sliding cylinder 7A is provided between the electromagnetic core 20 and the permanent magnet 17 provided on the piston 15. The sliding cylinder 7A is thick as described above. Is made thin, the interruption of the lines of magnetic force from the stator 21 is minimized. By this force, the piston 15 to which the permanent magnet 17 and the magnetic conductor 18 are fixed reciprocates in the cylinder 7 in the axial direction. When the piston 15 moves in a direction approaching the displacer 8, the gas in the compression chamber C formed between the piston 15 and the displacer 8 is compressed, and the communication hole 11, exhaust heat fins are compressed. 13, the regenerator 10, the endothermic fin 12, and the gap 9, and reaches the expansion chamber E formed between the distal end of the displacer 8 and the distal end portion 6 of the cylindrical portion 2. 15 with a predetermined phase difference. On the other hand, when the piston 15 moves away from the displacer 8, the inside of the compression chamber C becomes negative pressure, and the gas in the expansion chamber E passes from the expansion chamber E to the gap 9, the heat absorption fin 12, and the regeneration. The displacer 8 is pulled up with a predetermined phase difference with respect to the piston 15 by returning to the compression chamber C through the vessel 10, the exhaust heat fin 13, and the communication hole 11. By performing a reversible cycle consisting of two isothermal changes and an isovolume change in such a process, the vicinity of the expansion chamber E becomes a low temperature, while the vicinity of the compression chamber C becomes a high temperature.

  In this way, the piston 15 itself is a mover of a linear motor, the cylinder 7 is arranged through or in contact with a slight gap, and the stator 21 having the electromagnetic coil 19 on the outside thereof. The piston 15 that is a mover is driven by energizing the electromagnetic coil 19.

  As described above, in the embodiment, the cylinder 7, the piston 15 slidably inserted into the cylinder 7, the driving permanent magnet 17 fixed to the piston 15, and the outer peripheral side of the permanent magnet 17 In a linear motor having an electromagnetic coil 19 and a stator 21 having an electromagnetic core 20 disposed opposite to each other, the piston 17 includes at least one permanent magnet 17 for driving and a magnetic conductor 18, and these fixed By generating a driving force for reciprocating the piston 15 between the child 21 and the piston 15, a frame for fixing a permanent magnet is not required unlike the mover in the prior art, and the piston 15 By incorporating a driving component in itself, the structure can be simplified and the shape can be reduced.

  Further, since the cylinder 7 is made of PPS which is a synthetic resin, the magnetic lines of force generated from the stator 21 reach the permanent magnet 17 and the magnetic conductor 18 in the piston 15 without being blocked by the cylinder 7. The piston 15 can be efficiently reciprocated.

  FIG. 2 shows a second embodiment, and the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  A cylinder 40 is coaxially inserted in the casing 1. The cylinder 40 is made of, for example, a synthetic resin such as PPS including carbon short fibers as a reinforcing material, and has a sliding surface on its inner surface and is made of a nonmagnetic metal and has a thick wall. A thin sliding cylinder 40A is inserted. A piston 41 is housed inside the cylinder 40 so as to be slidable in the axial direction. The piston 41 has a piston body 41 </ b> A that slides in the cylinder 40. The piston body 41A is made of, for example, a synthetic resin such as PPS including molybdenum disulfide as a lubricant and carbon short fibers as a reinforcing material. A driving device 42 for reciprocating the piston 41 includes a permanent magnet 17 fixed to the inner peripheral surface of the piston main body 41 </ b> A, and a magnetic guiding body 44 provided inside the piston and fixed to a fixture 43. And a stator 21 having an annular electromagnetic coil 19 and an electromagnetic core 20 provided close to the outer peripheral side of the permanent magnet 17. In this embodiment, the stator 21 is integrally formed with the cylinder 40 formed of PPS or the like which is a synthetic resin by insert molding or the like. Further, the cylinder 40 covering the inner surface of the stator 21 is formed with a sufficiently small thickness, whereby the distance between the inner surface of the electromagnetic core 20 and the outer periphery of the permanent magnet 17 is shortened. The fixture 43 is fixed to the cylinder 40 by a mounting portion 45 provided on the cylinder 40.

  As described above, the stator 21 is arranged so as to cover the outer side of the piston 41, and the whole or inner surface of the stator 21 is molded integrally with the cylinder 40 by PPS or the like which is a synthetic resin. The number of parts around the cylinder 40 and the stator 21 can be reduced, and the number of assembly steps can be reduced.

  FIG. 3 shows a third embodiment, and the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  A cylinder 50 is coaxially inserted in the casing 1. The cylinder 50 is made of, for example, a synthetic resin such as PPS including carbon short fibers as a reinforcing material, and has a sliding surface on its inner surface and is made of a nonmagnetic metal and has a thick wall. A thin sliding cylinder 50A is inserted. A piston 15 is housed inside the cylinder 50 so as to be slidable in the axial direction. The piston 15 has a piston main body 15 </ b> A that slides in the cylinder 50, and a base end portion of the piston 15 is coaxially connected to the driving device 16. The driving device 16 is fixed to the inner peripheral surface of the piston main body 15A, and is fixed to the inner peripheral surface of the piston main body 15A, and on both axial sides and the inner peripheral side of the permanent magnet 17. The magnetic conductor 18 is arranged, and a stator 21 having an annular electromagnetic coil 19 and an electromagnetic core 20 provided in the vicinity of the outer peripheral side of the permanent magnet 17. In the present embodiment, the stator 21 is integrally formed with the cylinder 50 formed of PPS or the like which is a synthetic resin by insert molding or the like. Further, the cylinder 50 covering the inner surface of the stator 21 is formed with a sufficiently small thickness, whereby the distance between the inner surface of the electromagnetic core 20 and the outer periphery of the permanent magnet 17 is shortened. Further, a mount 51 that projects coaxially with the cylinder 7 is formed integrally with the cylinder 50 on the outer peripheral surface of the intermediate portion of the cylinder 50, and the cylinder 50 is inserted into the casing 1 by the mount 51. It is fixed to.

  As described above, the stator 21 is disposed so as to cover the outside of the piston 15, and the whole or inner surface of the stator 21 is molded integrally with the cylinder 50 by PPS or the like which is a synthetic resin. The number of parts around the cylinder 50 and the stator 21 can be reduced, and the number of assembling steps can be reduced.

  In addition, this invention is not limited to the above Example, A various deformation | transformation implementation is possible within the range of the summary of invention. For example, in each of the above embodiments, the cylinder is provided between the piston and the stator. However, the inner surface of the electromagnetic core of the stator may be the inner surface of the cylinder.

  In contrast to a linear motor having a primary side that generates a magnetic field and a secondary side that moves linearly, the magnetic field is applied to the secondary side by a primary side that moves linearly. It can also be used for generating linear generators. This is because a piston is used as a mover of a generator, a cylinder is arranged through or in contact with a slight gap, and a stator consisting of an electromagnetic coil and an electromagnetic core is arranged outside thereof, and the piston reciprocates. Thus, an induced current is generated in the electromagnetic coil. Even in this case, the same effect as the linear motor can be obtained.

It is sectional drawing which shows Example 1 of this invention. It is sectional drawing which shows Example 2 of this invention. It is sectional drawing which shows Example 3 of this invention. It is sectional drawing which shows a prior art example.

Explanation of symbols

7, 40, 50 Cylinders 15, 41 Pistons 15A, 41A Piston body 17 Permanent magnets for driving 18, 44 Magnetic conductor 19 Electromagnetic coil 20 Electromagnetic core 21 Stator

Claims (3)

  Linear having a cylinder, a piston slidably inserted into the cylinder, a permanent magnet fixed to the piston, and an electromagnetic coil and a stator having an electromagnetic core disposed opposite to the outer peripheral side of the permanent magnet The linear electromagnetic device according to claim 1, wherein the piston itself includes at least one permanent magnet or a magnetic conductor.   2. The linear electromagnetic device according to claim 1, wherein the cylinder is made of a synthetic resin.   2. The linear electromagnetic device according to claim 1, wherein the stator is disposed so as to cover the outside of the piston, and the whole or inner surface of the stator is integrally formed with the cylinder by a synthetic resin.

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