JP2009027921A - Linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear actuator which can enhance the reliability and can enhance the performance easily. <P>SOLUTION: The linear actuator comprises a stator 12, a mover 13 provided reciprocally for the stator, first pair of permanent magnets 14 and 15 facing the mover while adjoining mutually in the reciprocating direction and being provided on the stator under such a state as the magnetic poles are arranged perpendicularly to the reciprocating direction while reversing the mutual arrangement of the magnetic poles, second pair of permanent magnets 16 and 17 facing the mover while adjoining mutually in the reciprocating direction with the position being matched to that of the first pair of permanent magnets in the reciprocating direction and provided on the stator under such a state as the magnetic poles are arranged perpendicularly to the reciprocating direction while reversing the mutual arrangement of the magnetic poles, and a coil provided in the stator 12 wherein the first pair of permanent magnets and the second pair of permanent magnets reverse the magnetic poles facing the mover between the permanent magnets having positions matching in the reciprocating direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a linear actuator, and more particularly to improvement in reliability and performance.

  Linear actuators are used as compressor motors and the like because they can be driven with little loss by resonating together with a spring. And since the compressor using this linear actuator can exhibit excellent performance such as high efficiency, it is expected to be used for a refrigerator, a freezer, or an air conditioner.

  As the linear actuator, there is a voice coil motor. This voice coil motor is driven by a force generated in a coil by passing a current through the coil in a magnetic field generated by a permanent magnet, and is also called a movable coil type in which a mover including the coil moves.

  Further, as another linear actuator, there is a structure called a movable magnet type in which a permanent magnet and a coil are exchanged with respect to the movable coil type, and a mover including the permanent magnet moves.

  By the way, in the above-described movable coil type, since the mover includes a coil, it is necessary to pass an electric current through the mover, and the movement of the mover may cause disconnection in the power supply line. There was a problem that it was inferior in reliability.

  Further, the above-mentioned movable magnet type increases the weight of the permanent magnet when trying to obtain a high magnetic flux density in order to improve the performance. As a result, the weight of the mover increases. Therefore, there is a problem that the performance cannot be improved as desired.

  Accordingly, an object of the present invention is to provide a linear actuator that can improve reliability and can easily improve performance.

  In order to achieve the above object, a linear actuator according to claim 1 of the present invention is arranged in the same axial direction as the axial direction of the stator and the stator, and is supported so as to be capable of reciprocating in the axial direction. A linear actuator comprising a mover having at least a part of an iron member, the stator having a pair of protrusions extending relative to the mover from an inner wall surface in a cross section perpendicular to the axial direction thereof. A concave first cylindrical surface portion and a second cylindrical surface portion are formed at the tips of the convex portions, and the first cylindrical surface portions are adjacent to each other in the reciprocating direction. A first pair of permanent magnets provided on the stator is provided in a state where the magnetic poles are arranged perpendicularly to the reciprocating direction and opposed to the iron member in a state, and the arrangement of the magnetic poles is reversed. The second cylindrical surface The first pair of permanent magnets are aligned with each other in the reciprocating direction and are opposed to the iron member and adjacent to each other in the reciprocating direction. A second pair of permanent magnets provided on the stator is provided in a state where the magnetic poles are arranged orthogonal to each other and the arrangement of the magnetic poles is reversed, and the fixed pair is provided with the mover interposed therebetween. The first pair of permanent magnets and the second pair of permanent magnets are provided with a pair of coils provided on the child, and the magnetic poles are opposed to the iron member by permanent magnets that are positioned in the reciprocating direction. The stator has a cylindrical shape with a through hole extending in the reciprocating direction of the mover, and the mover is between the first and second pair of permanent magnets. And the reciprocating motion of the mover It has a cylindrical shape with a through hole extending in the direction, and the thickness of the movable element in a plane perpendicular to the reciprocating direction is formed by the convex portion of the stator in the same vertical plane as described above. It is characterized in that it is set thin so as to be denser than the magnetic flux density passing through the part that is not.

  Thus, in a state where the current of the coil on the stator side flows in one direction, for example, the stator, one permanent magnet of the first pair of permanent magnets, the iron member, and the second pair of permanent magnets reciprocate. A state in which a magnetic flux is formed in one permanent magnet and the stator loop that are aligned with one of the first pair of permanent magnets in the moving direction, and the current of the coil on the stator side is switched and flows in the opposite direction Then, a magnetic flux is formed by the stator, the other permanent magnet of the second pair of permanent magnets, the iron member, the other permanent magnet of the first pair of permanent magnets, and the loop of the stator. As a result, when the direction of the current of the coil on the stator side is switched alternately, the side of the first pair of permanent magnets and the second pair of permanent magnets on the stator side that guides the magnetic flux to the iron member is The direction of reciprocation is switched alternately, and the iron member, that is, the mover is reciprocated. Thus, since both the coil and the permanent magnet are provided on the stator side, there is no need to supply power to the mover side, and the moving mover does not cause a break in the power supply line to the coil. . Moreover, even if the weight of the permanent magnet increases when trying to obtain a high magnetic flux density for improving the performance, the weight of the mover does not increase. Furthermore, since there is no magnet in the mover, the operation of magnetizing the mover becomes unnecessary. In addition, since the mover is moved by the above-described magnetic flux loop, a part of the stator is not disposed as a back yoke on the opposite side to the permanent magnet of the mover.

  A linear actuator according to a second aspect of the present invention relates to the linear actuator according to the first aspect, wherein a set of the first pair of permanent magnets and the second pair of permanent magnets and the convex portion of the iron member is provided. A plurality of the sensors are provided adjacent to each other in the reciprocating direction.

As described above, a plurality of sets of the first pair of permanent magnets and the second pair of permanent magnets are provided in the same direction in the reciprocating direction of the mover. Magnetomotive force due to current can be obtained.
In addition, a plurality of sets of the first pair of permanent magnets and the second pair of permanent magnets are provided adjacent to each other in the reciprocating direction of the mover. Since a plurality of projections are provided adjacent to the reciprocating direction and projecting in the direction of the permanent magnet, the stroke is reduced, but the thrust can be increased in proportion to the number of teeth.

  The linear actuator according to a third aspect of the present invention is characterized in that, with respect to the linear actuator according to any one of the first to third aspects, the stator is composed of laminated steel plates laminated in the reciprocating direction.

  Thus, since the stator is composed of laminated steel plates laminated in the direction of the reciprocating movement of the mover, eddy current loss can be reduced compared to the case where the stator is cut and formed from the waste material, and the firing is reduced. Hysteresis loss can be reduced as compared with the case where the core is formed with a sintered iron core. In particular, when the stator is increased in size, the manufacture becomes easier as compared with the cutting and sintering from the waste material.

  As described in detail above, according to the linear actuator of the first aspect of the present invention, in the state where the current of the stator side coil flows in one direction, for example, the stator and the first pair of permanent magnets Magnetic flux is formed by one permanent magnet, iron member, and one of the second pair of permanent magnets, one permanent magnet aligned with one of the first pair of permanent magnets in the reciprocating direction, and the stator loop. In the state where the current of the coil on the stator side is switched and flows in the opposite direction, the stator, the other permanent magnet of the second pair of permanent magnets, the iron member, the other permanent of the first pair of permanent magnets Magnetic flux is formed by the loops of the magnet and the stator. As a result, when the direction of the current of the coil on the stator side is switched alternately, the side of the first pair of permanent magnets and the second pair of permanent magnets on the stator side that guides the magnetic flux to the iron member is The direction of reciprocation is switched alternately, and the iron member, that is, the mover is reciprocated.

  Thus, since both the coil and the permanent magnet are provided on the stator side, there is no need to supply power to the mover side, and the moving mover does not cause a break in the power supply line to the coil. . Therefore, reliability can be improved.

  Moreover, even if the weight of the permanent magnet or coil increases when trying to obtain a high magnetic flux density in order to improve the performance, the weight of the mover does not increase. Therefore, the performance can be easily improved.

Further, since the mover has no magnet, the work of magnetizing the mover becomes unnecessary.
Therefore, manufacture becomes easy and cost reduction can be achieved.

  In addition, since the mover is moved by the above-described magnetic flux loop, a part of the stator is not disposed as a back yoke on the opposite side to the permanent magnet of the mover. Therefore, the space on the opposite side to the permanent magnet of the mover can be used effectively.

  According to the linear actuator of the second aspect of the present invention, a plurality of sets of the first pair of permanent magnets and the second pair of permanent magnets are provided with their positions in the reciprocating direction of the mover being aligned. Therefore, it is possible to obtain a magnetomotive force due to the magnetic field and current of a stronger permanent magnet.

  In addition, a plurality of sets of the first pair of permanent magnets and the second pair of permanent magnets are provided adjacent to each other in the reciprocating direction of the mover. Since there are a plurality of protrusions that are adjacent to the direction of reciprocating movement and protrude in the direction of the permanent magnet, it is possible to obtain a stronger magnetomotive force due to the magnetic field and current of the permanent magnet and to the end face of the protrusion. A suction force can be applied efficiently.

  According to the linear actuator according to claim 3 of the present invention, the stator is composed of laminated steel plates laminated in the direction of reciprocation of the mover. Current loss can be reduced, and hysteresis loss can be reduced as compared with the case of being formed by sintering. In particular, when the stator is increased in size, the manufacture becomes easier as compared with the cutting and sintering from the waste material. Therefore, the performance can be improved, and the increase in the size of the stator accompanying the increase in the overall size can be easily accommodated.

  The linear actuator of 1st Embodiment of this invention is demonstrated below with reference to FIGS.

  The linear actuator 11 according to the first embodiment includes a yoke (stator) 12, a mover 13 provided inside the yoke 12 so as to be able to reciprocate, and a pair of permanent magnets (first magnet) fixed to the yoke 12. A pair of permanent magnets 14 and 15, a pair of permanent magnets (second pair of permanent magnets) 16 and 17 fixed to the yoke 12, and two coils 18 fixed to the yoke 12 are provided.

  The yoke 12 has a rectangular tube shape as a whole by forming a through hole 21 at its center position. The through-hole 21 has two cylindrical surface portions 22 which are formed in a shape in which the inner peripheral surface of the cylinder is cut in two places parallel to the axis thereof at a predetermined interval and which are opposed to each other in a separated state. A flat surface portion 23 extending outward from the edge portions of both ends along the direction connecting the cylindrical surface portions 22, and an orthogonal edge to the flat surface portion 23 from the opposite edge portion with respect to each cylindrical surface portion 22 of each flat surface portion 23. A flat surface portion 24 extending outward and a planar inner surface portion 25 extending in a direction connecting the cylindrical surface portions 22 and connecting corresponding ones of the flat surface portions 24 are provided. Here, the two cylindrical surface portions 22 have the same diameter, the same length, and the same width, and are arranged coaxially. Further, in the flat surface portion 23, the flat surface portion 24, and the inner surface portion 25, concave portions 30 that are recessed in the radial direction are formed on both sides of each cylindrical surface portion 22 in the circumferential direction.

The yoke 12 is formed by punching a thin steel plate into a shape having the two cylindrical surface portions 22, the four flat surface portions 23, the four flat surface portions 24, and the two inner surface portions 25 with a press. A member 27 is formed, and the base member 27 is made of a laminated steel plate that is joined while being laminated while aligning a plurality of base members 27 in the penetrating direction of the through hole 21.
Further, the yoke 12 is not provided with a back yoke having a shape extending inside the movable element 13.

  In the yoke 12, a portion between each inner surface portion 25 and the outer surface portion 26 that is adjacent to and parallel to each inner surface portion 25 is a coil winding portion 28, and as a result, such coil winding is performed. Two portions 28 are provided in parallel to each other. A coil 18 is wound around the coil winding portion 28 over the entire width of the inner surface portion 25. As a result, each coil 18 is fixed to the yoke 12 in a ring shape.

  The permanent magnets 14 and 15 are made of ferrite magnets having the same diameter, the same length and the same width, which are formed by cutting a cylinder in parallel at two places at predetermined intervals, and are coaxial with each other in the circumferential direction. The cylinders are aligned and positioned adjacent to each other in the axial direction, and are bonded and fixed to one cylindrical surface portion 22. Here, these permanent magnets 14 and 15 have radial anisotropy in which magnetic poles are arranged in a direction orthogonal to the axial direction, and the arrangement of the magnetic poles is reversed. Specifically, the permanent magnet 14 on one side in the penetration direction of the through hole 21 has an N pole 14a arranged on the outer diameter side and an S pole 14b arranged on the inner diameter side, and the other permanent magnet 15 has an N pole. 15a is disposed on the inner diameter side and the S pole 15b is disposed on the outer diameter side. The concave portions 30 of the yoke 12 are arranged on both sides in the direction orthogonal to the arrangement direction of the permanent magnets 14 and 15.

  The permanent magnets 16 and 17 are made of ferrite magnets having the same diameter, the same length, and the same width, which are formed by cutting the inner peripheral surface of the cylinder at a predetermined interval and parallel to the axis thereof. None Positioned in the circumferential direction so that the positions in the circumferential direction are aligned and separated from the permanent magnets 14 and 15 on the other cylindrical surface portion 22 on the opposite side in the circumferential direction. They are joined and fixed together. Here, these permanent magnets 16 and 17 have radial anisotropy in which magnetic poles are arranged in a direction orthogonal to the axial direction, and the arrangement of the magnetic poles is reversed. Specifically, the permanent magnet 16 on one side in the penetration direction of the through hole 21 has an N pole 16a disposed on the inner diameter side and an S pole 16b disposed on the outer diameter side, and the other permanent magnet 17 has an N pole. 17a is arranged on the outer diameter side and S pole 17b is arranged on the inner diameter side. The concave portions 30 of the yoke 12 are arranged on both sides in the direction orthogonal to the arrangement direction of the permanent magnets 16 and 17.

  As described above, the pair of permanent magnets 14 and 15 and the pair of permanent magnets 16 and 17 are permanent magnets whose positions are aligned in the penetrating direction of the through hole 21, and the magnetic poles on the inner diameter side, that is, the mover 13 side are reversed. That is, the permanent magnet 14 and the permanent magnet 16 that are aligned in the penetration direction of the through hole 21 have the inner poles opposite to each other, and the permanent magnet 15 and the permanent magnet 17 that are aligned in the penetration direction of the through hole 21 are also mutually. The magnetic pole on the inner diameter side is reversed.

  The mover 13 has a cylindrical shape with a through hole 31 formed in the center, and has an outer diameter slightly smaller than the inner diameter of the permanent magnets 14 to 17. The movable element 13 is inserted inside the cylindrical surface portion 22 of the yoke 12, that is, on the inner diameter side of the permanent magnets 14 to 17 so as to be coaxial with the movable element 13 so as to pass through the through hole 21 with respect to the yoke 12. It can be reciprocated in the direction. Here, the length of the mover 13 in the axial direction is shorter than the length of the through hole 21 of the yoke 12 in the through direction.

The movable element 13 is formed by punching a thin steel plate with a press to form an annular base member 32 having a through hole 31 on the inside, and a plurality of the base members 32 are arranged in the through direction of the through hole 31. It consists of laminated steel plates that are laminated and bonded together.
Thereby, the whole needle | mover 13 consists of an iron member.

  In the linear actuator 11 having the above structure, an alternating current (sine wave current, rectangular wave current) is passed through the coils 18 on both sides in synchronization. Here, in the coils 18 on both sides, currents in opposite directions are caused to flow along the penetrating direction of the through hole 21 in the portions closer to the mover 13 than the respective coil winding portions 28.

  In a state in which no current flows through the coils 18 on both sides, the yoke 12, the permanent magnet 15, the mover 13, the permanent magnet 14 and the pair of permanent magnets 14 and 15 as shown by a two-dot chain line in FIG. A magnetic flux is formed in a loop connecting the yoke 12 in this order, and a pair of permanent magnets 16 and 17 forms a magnetic flux in a loop connecting the yoke 12, the permanent magnet 16, the mover 13, the permanent magnet 17 and the yoke 12 in this order. Is done. At this time, the movable element 13 is stopped.

  And, for example, as shown in FIG. 3, one coil 18 (on the left side in FIG. 3) has one direction in the penetration direction of the through hole 21 on the movable element 13 side (the direction through the paper surface in FIG. 3 from the back to the front). When a current is passed so as to flow in a direction, a magnetomotive force is generated in one direction (downward direction in FIG. 3) in the coil winding portion 28 inside. Then, by the pair of permanent magnets 14 and 15 and the pair of permanent magnets 16 and 17, the yoke 12 and the pair of permanent magnets 14 are disposed on the one coil 18 side as shown by a two-dot chain line in FIGS. 3 and 4. , 15 (the back side in FIG. 3), the position of the permanent magnet 15 and the position of the one permanent magnet 15 in the penetrating direction of the through hole 21 of the pair of permanent magnets 16 and 17 is the same. A magnetic flux is formed by a loop connecting the matching permanent magnet 17 and yoke 12 in this order. At the same time, a current is applied to the coil 18 on the other side (right side in FIG. 3) so as to flow in the reverse direction in the direction of penetration of the through hole 21 (direction in which the paper surface in FIG. When flowing, a magnetomotive force is generated in the coil winding portion 28 in one direction (downward direction in FIG. 3). Then, as shown by a two-dot chain line in FIG. 3, the yoke 12 and the pair of permanent magnets 14, 15 are also provided on the other coil 18 side by the pair of permanent magnets 14, 15 and the pair of permanent magnets 16, 17. One permanent magnet 17 and the yoke 12 that are aligned with the one permanent magnet 15 in the penetrating direction among the permanent magnet 15 on one side (the back side in FIG. 3), the mover 13, and the pair of permanent magnets 16 and 17 are arranged. A magnetic flux is formed by a loop connecting in this order.

  As described above, the mover 13 moves in one direction in the penetration direction of the through hole 21 (the direction passing through the paper surface in FIG. 3 from the front to the back, the right direction in FIG. 4).

  Next, as shown in FIGS. 5 and 6, one coil 18 (left side in FIG. 5) has a reverse direction in the direction of penetration of the through hole 21 on the movable element 13 side (the paper surface in FIG. When an electric current is passed so as to flow in the direction of penetration, a magnetomotive force is generated in one direction (upward direction in FIG. 5) in the coil winding portion 28 inside thereof. Then, as shown by a two-dot chain line in FIG. 5 and FIG. 6, the yoke 12, the pair of permanent magnets 14, The permanent magnet 14 on the other side of FIG. 15 (the front side in FIG. 5), the mover 13, and the other permanent magnet 14 are aligned in the penetrating direction of the through hole 21 of the pair of permanent magnets 16, 17. A magnetic flux is formed by a loop connecting the other permanent magnet 16 and the yoke 12 in this order. At the same time, a current is applied to the coil 18 on the other side (right side in FIG. 5) so as to flow in one direction in the direction of penetration of the through hole 21 (direction in which the paper surface in FIG. When flowing, a magnetomotive force is generated in one direction (upward direction in FIG. 5) in the coil winding portion 28 inside thereof. Then, as shown by a two-dot chain line in FIG. 5, the pair of permanent magnets 14 and 15 and the pair of permanent magnets 16 and 17 cause the yoke 12 and the pair of permanent magnets 14 and 15 to be placed on the other coil 18 side. The other permanent magnet 14 on the other side (the front side in FIG. 5), the mover 13, and the other permanent magnet 14, 17 is aligned with the other permanent magnet 14 in the penetration direction of the through hole 21. A magnetic flux is formed by a loop connecting the permanent magnet 16 and the yoke 12 in this order.

  As described above, the movable element 13 moves in the reverse direction in the penetration direction of the through hole 21 (the direction penetrating the paper surface in FIG. 5 from the back to the front, the left direction in FIG. 6).

  The direction of current flow to both coils 18 is alternately changed by the alternating current, so that the above operation is repeated, so that the movable element 13 moves with a predetermined stroke in the through direction of the through hole 21 with respect to the yoke 12. It will reciprocate.

  According to the linear actuator 11 of the first embodiment described above, since the coil 18 is provided not on the mover 13 but on the yoke 12, there is no need to supply power to the mover 13 side, and the moving mover 13 is a coil. No disconnection is caused in the power supply line to 18. Therefore, the reliability with respect to continuous operation etc. can be improved.

  Further, since the permanent magnets 14 to 17 are provided not on the mover 13 but on the yoke 12, the weights of the permanent magnets 14 to 17 and the coil 18 increase when a high magnetic flux density is to be obtained in order to improve the performance. However, the weight of the mover 13 does not increase. Therefore, performance improvement (thrust increase) can be easily achieved.

  In addition, since there is no permanent magnet in the mover 13, it is not necessary to magnetize the mover 13, and no attracting force acts on the mover 13 when the mover 13 is manufactured. Is easy to manufacture. Therefore, manufacture becomes easy and cost reduction can be achieved.

  In addition, since the movable element 13 is moved by the magnetic flux of the loop as described above, a part of the yoke 12 is not arranged as a back yoke on the opposite side, that is, on the inner diameter side with respect to the permanent magnets 14 to 17 of the movable element 13. it can. Therefore, the space opposite to the permanent magnets 14 to 17 of the mover 13, that is, the space on the through hole 31 side can be effectively used. Specifically, the degree of freedom in design when a separate cylinder, its piston, or the like is arranged in the through hole 31 is greatly increased.

  In addition, since the yoke 12 is made of laminated steel plates laminated in the direction of reciprocating movement of the mover 13, eddy current loss can be reduced as compared with the case where the yoke 12 is formed by cutting out from the bulk material, Hysteresis loss can be reduced as compared with the case of forming by sintering. Therefore, performance can be improved. In particular, when the yoke 12 is increased in size, the manufacture becomes easier as compared with the cutting and sintering from the waste material. Therefore, it is possible to easily cope with an increase in the size of the yoke 12 accompanying an increase in the size of the whole.

  As the permanent magnets 14 to 17, it is possible to use rare earths such as neodymium and samarium cobalt, or plastic magnets in addition to the above-mentioned ferrite magnets, but it is costly to use ferrite magnets. More preferable from the viewpoint of reduction.

  The linear actuator 11 is generally used by incorporating a spring in the movable element 13 or by resonating with a spring placed outside, but of course, it can be used as it is. is there.

  Further, the linear actuator 11 can be used as a linear servo actuator capable of controlling speed and position by providing a sensor for detecting position, speed, etc. and performing closed loop control.

  Next, the linear actuator of 2nd Embodiment of this invention is demonstrated below with reference to FIG. 7 and FIG.

  The linear actuator 51 of the second embodiment includes a yoke (stator) 52, a mover 53 that can be reciprocated inside the yoke 52, and four sets of permanent magnets (first) fixed to the yoke 52. A pair of permanent magnets) 54, 55, four sets of permanent magnets (second pair of permanent magnets) 56, 57 fixed to the yoke 52, and eight coils 58 fixed to the yoke 52. Yes.

The yoke 52 has a cylindrical shape as a whole by forming a through hole 61 at its center position. The through hole 61 has a shape obtained by cutting the inner peripheral surface of the cylinder at a predetermined interval at two locations parallel to the axis thereof, and has eight cylindrical surface portions 62 arranged at equal intervals in the circumferential direction. . Here, between the cylindrical surface parts 62 adjacent to each other in the circumferential direction is a concave part 63 that is recessed outward in the radial direction. As a result, between the concave parts 63 adjacent to each other in the circumferential direction, the cylindrical surface part 62 is provided. The convex part 64 which has is formed.
Here, the eight cylindrical surface portions 62 have the same diameter, the same length, and the same width, and are arranged coaxially. Although not shown in the drawings, this yoke 52 is formed by punching a thin steel plate into a shape having the eight concave portions 63 and the convex portions 64, and forming a base member, as in the first embodiment. The base member is made of a laminated steel plate in which a plurality of base members are laminated in the penetrating direction of the through-hole 61 while being laminated.
Further, the yoke 52 is not provided with a back yoke having a shape extending inside the movable element 53.

  In the second embodiment, a coil 58 is wound around each convex portion 64 of the yoke 52 so as to alternately extend in the axial direction and the circumferential direction. As a result, each coil 58 has a ring shape to form a yoke. 52 is fixed.

  The permanent magnets 54 and 55 are made of ferrite magnets having the same diameter, the same length and the same width, which are formed by cutting a cylinder in parallel at two places at predetermined intervals, and are coaxial with each other in the circumferential direction. They are aligned and positioned adjacent to each other in the axial direction, and are fixedly joined to a common cylindrical surface portion 62. Here, these permanent magnets 54 and 55 are of radial anisotropy in which magnetic poles are arranged in a direction orthogonal to the axial direction, and the arrangement of the magnetic poles is reversed. Specifically, the permanent magnet 54 on one side in the penetration direction of the through hole 61 has an N pole 54a arranged on the outer diameter side and an S pole 54b arranged on the inner diameter side, and the other permanent magnet 55 has an N pole. 55a is arranged on the inner diameter side and the S pole 55b is arranged on the outer diameter side. And four sets of such a pair of permanent magnets 54 and 55 are arrange | positioned so that each cylindrical surface part 32 arrange | positioned every other in the circumferential direction may make radial shape.

  The permanent magnets 56 and 57 are made of ferrite magnets having the same diameter, the same length, and the same width, which are formed by cutting the inner peripheral surface of the cylinder at a predetermined interval and parallel to the axis thereof. None Positioned in the circumferential direction so as to be adjacent to each other in the axial direction and joined and fixed to a common cylindrical surface portion 62. Here, these permanent magnets 56 and 57 are of radial anisotropy in which magnetic poles are arranged in a direction orthogonal to the axial direction, and the arrangement of the magnetic poles is reversed. Specifically, the permanent magnet 56 on one side in the penetration direction of the through hole 61 has an N pole 56a disposed on the inner diameter side and an S pole 56b disposed on the outer diameter side, and the other permanent magnet 57 is disposed on the N pole. 57a is arranged on the outer diameter side, and S pole 57b is arranged on the inner diameter side. And four sets of such a pair of permanent magnets 56 and 67 are arranged so as to radiate to the remaining cylindrical surface portions 32 arranged alternately in the circumferential direction.

  As described above, the pair of permanent magnets 54, 55 and the pair of permanent magnets 56, 57 are the permanent magnets whose positions are aligned in the penetrating direction of the through hole 61, and the magnetic poles of the mover 53 are reversed. That is, the permanent magnet 54 and the permanent magnet 56 that are aligned in the through direction of the through hole 61 have the magnetic poles on the inner diameter side opposite to each other, and the permanent magnet 55 and the permanent magnet 57 that are aligned in the through direction of the through hole 61 are also mutually connected. The magnetic pole on the inner diameter side is reversed.

  Here, a pair of permanent magnets 54 and 55 and a pair of permanent magnets 56 and 57 which are adjacent to each other in the circumferential direction form a pair, and such a pair is a position in the through direction of the through hole 21. A plurality of sets, specifically four sets are provided.

  The mover 53 includes an iron member 72 having a cylindrical shape with a through hole 71 formed in the center, and a main portion 73 provided on one side in the axial direction of the iron member 72. Reference numeral 73 denotes a large-diameter cylindrical portion 75 that is coaxially adjacent to the iron member 72 and adjacent to the iron member 72, and a small-diameter cylinder that is coaxially provided on the opposite side of the large-diameter cylindrical portion 75 with a smaller diameter. Part 76. Note that the outer diameters of the iron member 72 and the large-diameter cylindrical portion 75 are slightly smaller than the inner diameters of the permanent magnets 54 to 57. The mover 53 is reciprocated in the through direction of the through hole 61 with respect to the yoke 52 by being inserted inside the cylindrical surface portion 62 of the yoke 52, that is, on the inner diameter side of the permanent magnets 54 to 57 so as to be coaxial with them. It is provided to be movable. Here, the length in the axial direction of the iron member 72 is shorter than the length in the through direction of the through hole 61 of the yoke 52. Further, a bolt 78 for fixing a shaft or the like passing through the inner diameter side is screwed into the small diameter cylindrical portion 76 in the radial direction.

  The mover 53 is made of a synthetic resin such as engineering plastic whose main portion 73 is a nonmagnetic material, and the iron member 72 is made of a sintered material. The mover 53 is formed by insert molding of synthetic resin with the iron member 72 as a nest.

  According to the linear actuator 51 of the second embodiment described above, the same effect as that of the linear actuator 11 of the first embodiment can be exhibited. In addition, the pair of permanent magnets 54 and 55 and the pair of permanent actuators can be obtained. Since a plurality of sets of magnets 56 and 57, specifically four sets, are distributed, the yoke thickness can be reduced and the weight can be reduced.

  Since the thickness of the mover can be reduced and the weight of the movable part can be reduced, the responsiveness is improved.

  In the second embodiment, the same changes as in the first embodiment can be made.

  Next, a linear actuator according to a third embodiment of the present invention will be described below with reference to FIG. 9, focusing on the differences from the second embodiment. In addition, the same code | symbol is attached | subjected to the part similar to 2nd Embodiment, and the description is abbreviate | omitted.

  In the third embodiment, the pair of permanent magnets 54 and 55 and the pair of permanent magnets 56 and 57 are aligned with each other in the circumferential direction so as to be adjacent to each other in the penetrating direction of the through hole 61. The permanent magnets 54 and 55 and a pair of permanent magnets 56 and 57 are provided. That is, each pair of permanent magnets 54 and 55 is provided with a pair of permanent magnets 54 and 55 in a state where the positions in the circumferential direction are aligned and adjacent to each other in the through direction of the through hole 61. The magnets 56 and 57 are provided with a pair of permanent magnets 56 and 57 in a state where the positions in the circumferential direction are aligned and adjacent to each other in the through direction of the through hole 61.

  In addition, the iron member has a plurality of, specifically, two locations, adjacent to the direction of the permanent magnet, that is, the annular protrusion 80 projecting toward the outer diameter side in the direction of penetration of the through hole 61, that is, the direction of reciprocation of the mover 53. Is provided. Here, the convex portion 80 on one side in the penetration direction of the through hole 61 causes magnetic flux to be generated between the permanent magnets 54 and 55 and the permanent magnets 56 and 57 provided on the same side in the penetration direction of the through hole 61. On the other hand, the convex portion 80 on the opposite side in the penetrating direction of the through hole 61 causes magnetic flux to pass between the permanent magnets 54 and 55 and the permanent magnets 56 and 57 provided on the same side in the penetrating direction of the through hole 61. Lead.

  According to the linear actuator 51 of the third embodiment described above, the same effect as that of the second embodiment can be exhibited. In addition, the pair of permanent magnets 54 and 55 and the pair of permanent magnets 56 and 57 can be obtained. Are provided in the direction of the reciprocating motion of the mover 53, the magnetic field of the stronger permanent magnet and the magnetomotive force due to the current can be obtained. In addition, since the iron member 72 is provided with a plurality of convex portions 80 that are adjacent to the reciprocating direction of the mover 53 and project in the direction of the permanent magnets 54 to 57, the convex portion 80 is provided in any of the reciprocating motions. Thus, it is possible to efficiently apply a suction force to the end face, and as a result, it is possible to drive the mover with a larger force.

  In addition, about all the linear actuators 11 mentioned above, you may make it reverse a structure by the center axis line side and an outer diameter side. For example, as shown in FIGS. 10 and 11, permanent magnets 14 and 15 and permanent magnets 16 and 17 are arranged on the outer diameter side of the yoke 12 including the coil 18, and the permanent magnets 14 and 15 and the permanent magnets 16 and 17 are arranged. A cylindrical mover 13 is provided on the outer diameter side so as to be able to reciprocate. If configured in this manner, the coil 18 becomes smaller when the same size is adopted as a whole, so that the copper loss is reduced, the area for generating force can be increased, and the efficiency can be improved.

It is a front sectional view showing the linear actuator of the first embodiment of the present invention. It is a sectional side view which shows the linear actuator of 1st Embodiment of this invention, Comprising: The state of the magnetic flux when the electric current is not flowing into the coil is shown with a dashed-two dotted line. It is a front sectional view showing a linear actuator of a 1st embodiment of the present invention, and shows a state of magnetic flux when a current is flowing through a coil in one direction by a two-dot chain line. It is a sectional side view which shows the linear actuator of 1st Embodiment of this invention, Comprising: The state of the magnetic flux when the electric current is flowing through the coil to one direction is shown with a dashed-two dotted line. It is a front sectional view showing a linear actuator of a 1st embodiment of the present invention, and shows a state of magnetic flux when a current is flowing through a coil in the reverse direction by a two-dot chain line. It is a sectional side view which shows the linear actuator of 1st Embodiment of this invention, Comprising: The state of the magnetic flux when the electric current is flowing through the coil in the reverse direction is shown with a dashed-two dotted line. It is a front sectional view showing a linear actuator of a second embodiment of the present invention. It is sectional drawing which follows the XX line shown in FIG. 7 which shows the linear actuator of 2nd Embodiment of this invention. It is sectional drawing which follows the XX line shown in FIG. 7 which shows the linear actuator of 3rd Embodiment of this invention. It is a front sectional view showing a modification of the linear actuator of the first embodiment of the present invention. It is a sectional side view which shows the modification of the linear actuator of 1st Embodiment of this invention.

Explanation of symbols

11 Linear actuator 12 Yoke (stator)
13 Movers 14, 15 Permanent magnets (first pair of permanent magnets)
14a, 15a, 16a, 17a N pole (magnetic pole)
14b, 15b, 16b, 17b S pole (magnetic pole)
16, 17 Permanent magnets (second pair of permanent magnets)
18 Coil 51 Linear actuator 52 Yoke (stator)
53 Movers 54, 55 Permanent magnets (first pair of permanent magnets)
54a, 55a, 56a, 57a N pole (magnetic pole)
54b, 55b, 56b, 57b S pole (magnetic pole)
56, 57 Permanent magnets (second pair of permanent magnets)
58 Coil 72 Iron member 80 Convex

Claims (3)

A stator,
A linear actuator which is arranged in the same axial direction as the axial direction inside the stator and is supported so as to be able to reciprocate in the axial direction.
The stator has a pair of convex portions extending from an inner wall surface in a cross section perpendicular to the axial direction thereof toward the mover, and a concave first cylindrical surface portion and a second cylindrical portion are formed at the tips of the convex portions. The cylindrical surface part is formed,
The first cylindrical surface portion is arranged adjacent to each other in the reciprocating direction, facing the iron member and arranged perpendicular to the reciprocating direction, and the arrangement of the magnetic poles is reversed. A first pair of permanent magnets provided on the stator in a state are provided;
The second cylindrical surface portion is aligned with the position of the first pair of permanent magnets in the reciprocating direction and is opposed to the iron member in a state adjacent to each other in the reciprocating direction. And a second pair of permanent magnets provided on the stator in a state where the magnetic poles are arranged perpendicular to the reciprocating direction and the arrangement of the magnetic poles is reversed,
A pair of coils arranged on the stator and sandwiched between the movers,
The first pair of permanent magnets and the second pair of permanent magnets have opposite magnetic poles facing the iron member between permanent magnets that are aligned in the reciprocating direction,
The stator has a cylindrical shape having a through hole extending in a reciprocating direction of the mover, and the mover is disposed between the first and second pair of permanent magnets. , A cylindrical shape having a through hole extending in the reciprocating direction of the mover,
The thickness of the mover in the plane perpendicular to the reciprocating direction is thin so as to be denser than the magnetic flux density passing through the portion of the stator in which the convex portion is not formed in the same vertical plane. A linear actuator characterized by being set.   2. The set of the first pair of permanent magnets and the pair of second pair of permanent magnets and a set of convex portions of the iron member are provided adjacent to each other in the reciprocating direction. Linear actuator.   The linear actuator according to claim 1, wherein the stator is made of laminated steel plates laminated in the reciprocating direction.

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