JP2006296161A - Linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear actuator which can constitute a length in the axial direction short without using a fastening component of a spring inclusion type such as a screw. <P>SOLUTION: The actuator is provided with a stator 15 provided with a core unit 12 having an electromagnetic coil 11, and flanges 14 which are arranged on both ends of the core unit and have bearings and with iron core members 16 in at least a part. The actuator is also provided with a moving member 17 arranged by penetrating the stator and supported by the bearing along the axial direction of the stator so that it can reciprocate, an arcuate permanent magnet 16 arranged in a face confronted with the moving member of the stator in a state where a magnetic pole is made to intersect with the axial direction, elastic members 19 arranged on both ends of a flange, and a pair of stoppers 20 fixed on both ends of the moving member. Since outer ends of the elastic member are sandwiched with the stopper members, the length in the axial direction can be made short without using the fastening component such as the screw. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a linear actuator, and more particularly to improvement in performance and simplification of a structure of a vibration type linear actuator.

  Generally, as a small-stroke linear motor, a permanent magnet is attracted by a voice coil motor that generates thrust by passing current through an electromagnetic coil placed in a permanent magnet field, an electromagnetic solenoid that attracts iron pieces with an electromagnet, or an electromagnet. A repulsive moving magnet type is known. Further, as shown in the following document, a linear motor having a new operating principle that moves only an iron core while being a permanent magnet type has recently been proposed. These linear motors are used by resonating with a combination of springs (mechanical springs, magnetic springs, gas springs, etc.), but because they are direct drives, they serve as highly efficient small-stroke actuators such as compressor piston drives and electric razors. The application example is increasing mainly on high efficiency, high speed, high frequency operation use.

For example, in the linear actuator shown in FIG. 11, the inner core 1 is fixed to the shaft 3 with a screw 2 or the like to form a mover, and the outer core 5, the lid flange 6, or the like is fastened to the flange 4 with a bolt 7. Is configured. Further, the resonance unit 8 including the resonance coil 8 a is fastened with the bolt 9 in series with the shaft 3.
Japanese Patent Application No. 2004-143819 Japanese Patent Application No. 2004-145243

However, since the linear actuator configured in this way is assembled by fastening the mover or stator with screws or bolts, the number of parts increases, the number of assembly steps increases, and the manufacturing cost increases. It was. The resonance unit 8 is also configured separately from the actuator and is fastened with bolts.
For this reason, the number of parts and assembly man-hours have been increased. In addition, since each component is fastened with bolts, screws, etc., there is a risk that the component will loosen during operation.
Also, since the mass of the mover is large, in order to increase the resonance frequency, it is necessary to increase the spring constant of the resonance coil, and the assembling work is also difficult. Furthermore, since the mass of the mover is large, the vibration accompanying the operation of the actuator is also large.

  In order to achieve the above object, a linear actuator of the present invention includes a stator having a core unit provided with electromagnetic coils, flanges provided at both ends of the core unit and provided with bearings, and an iron member in part. A mover that is disposed through the stator and supported by the bearing so as to be reciprocable along the axial direction of the stator, and a surface that faces the stator and the mover. Further, an arc-shaped permanent magnet disposed with the magnetic poles orthogonal to the axial direction, elastic members disposed at both ends of the flange, and a pair of stoppers fixed at substantially both ends of the mover The outer end of each elastic member is clamped by the stopper member.

  In the present invention, the core unit includes a leaf spring-like bearing disposed at both ends and penetrating the mover.

  In the present invention, the core unit is characterized in that an electromagnetic coil is disposed on the outer peripheral side at the center in the axial direction, and the permanent magnet is divided into two in the axial direction.

  In the present invention, the elastic member is a coil spring.

  In the present invention, the elastic member is a rubber spring.

  In the present invention, the elastic member is a gas pressure spring.

  Since this invention consists of an above-described structure, there can exist an effect which is demonstrated below.

  According to the present invention, a stator having a core unit having an electromagnetic coil, flanges provided at both ends of the core unit and having a bearing, and an iron member at least partially, and penetrating the stator The magnetic poles are arranged in the axial direction on the movable element supported by the bearing so as to be reciprocable along the axial direction of the stator, and on the opposing surfaces of the stator and the movable element. The stopper member is composed of an arc-shaped permanent magnet disposed in an orthogonal state, an elastic member disposed at both ends of the flange, and a pair of stopper members fixed at substantially both ends of the mover. Since the outer ends of each of the elastic members are clamped, a fastening part such as a screw is not required for assembly, and the number of man-hours can be greatly reduced. Moreover, there is no worry that the parts will loosen during operation. In addition, the axial dimension of the linear actuator can be shortened by reducing the number of parts. Further, the reliability of the actuator can be improved by reducing the number of assembly steps and the number of parts, and the manufacturing cost can be reduced.

  In the linear actuator of the present invention, the length of the mover (shaft) can be greatly shortened, so that the mass of the movable part can be reduced, and the spring constant of the elastic member for increasing the resonance frequency can be set low. Furthermore, since the spring constant can be reduced, the assembly work of the actuator becomes easy. Further, since the mass of the movable part can be reduced, the reaction force received by the core unit during operation is reduced, and an actuator with less vibration can be realized.

  Since the elastic members are disposed at both ends of the stator and the outer ends of the elastic members are sandwiched by the stopper members provided at both ends of the mover (shaft), it is possible to connect parts without requiring fastening parts such as screws. The purpose of reducing the number of points and the length of the mover is achieved.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating an embodiment. FIG. 1 is a perspective view showing an embodiment of a linear actuator according to the present invention, and FIG. 2 is a sectional view thereof. Here, the linear actuator 10 includes a stator 15 having a core unit 12 having an electromagnetic coil 11, flanges 14 provided at both ends of the core unit 12 and having a bearing 13, and an iron member 16 in part. A mover 17 that is disposed through the stator 15 and supported by the bearing 13 so as to be reciprocally movable along the axial direction of the stator 15, and the mover of the stator 15. 17, arc-shaped permanent magnets 18 arranged with magnetic poles orthogonal to the axial direction, elastic members 19 arranged at both ends of the flange 14, and the movable element 17. It consists of a pair of stopper members 20 fixed at substantially both ends, and the stopper members 20 sandwich the outer ends of the elastic members 19 respectively.

  The core unit 12 includes the electromagnetic coils 11 at both ends and a plurality of ring-shaped permanent magnets 18 on the inner peripheral surface of the through hole. The stator 15 includes an electromagnetic coil 11, a core unit 12, a bearing 13, a flange 14, and the like. The flange 14 has a prismatic shape and is disposed on both sides of the core unit 12. A bearing 13 that slidably supports a mover (shaft) 17 is provided on the inner periphery of the through hole of the flange 14. As the bearing 13, a ball bushing bearing or the like can be used. A concave portion 14 a is formed at the outer end of the flange 14, and an end portion of a coil spring which is an elastic member 19 is attached. Further, the outer end of the elastic member 19 is held by a stopper member 20 fixed to the shaft 17 via a spring retainer 21. In this embodiment, the stopper member 20 uses an E-ring and is engaged with a locking groove 17 a formed in the movable element 17.

  The mover 17 is a rod-shaped shaft in the present embodiment, and is disposed through the core unit 12, the flange 14, the elastic member 19, and the spring retainer 21. Further, an inner core, which is an iron member 16, is fixed to a portion facing the permanent magnet 18 in the approximate center of the mover 17. As described above, the movable element 17 is elastically supported by the elastic member 19 in the reciprocating direction, and the movable element 17 and the elastic member 19 constitute a vibration system in the reciprocating direction.

In the linear actuator configured as described above, the mover 17 is stopped when no current is passed through the electromagnetic coil 11. Moreover, the movable element 17 can be reciprocated in the axial direction by passing an alternating current through the electromagnetic coil 11. At this time, by passing an alternating current substantially equal to the frequency determined from the spring constant of the elastic member 19 and the mass of the mover 17, the resonance state is obtained and the amplitude of the mover 17 can be increased. Furthermore, since the linear actuator 10 inserts the mover 17 into the stator 15, attaches the elastic member 19 from both ends, attaches the spring retainer 21 from the outside, and fits the stopper member 20, the one-touch operation. Can be assembled with. Also, since no screws are used, there is no risk of loosening of parts.
In the first embodiment described above, the permanent magnet 18 is attached to the stator 15 side, but the present invention is not limited to this and may be attached to the mover 17 side.

  FIG. 3 is a perspective view showing a second embodiment of the linear actuator 30 according to the present invention, and FIG. 4 is a sectional view thereof. Here, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the present embodiment, the stator 31 includes a cylindrical core unit 32 and a cylindrical flange 33, and a mover (shaft) 17 is inserted through the center thereof. In addition, a coil spring 19 that is an elastic member is disposed at both ends of the core unit 32, and is sandwiched between E-rings 20 that are stopper members fitted to the shaft via spring retainers 21.

In the core unit 32, an electromagnetic coil 35 is disposed at the center in the axial direction and on the outer peripheral side, and a permanent magnet 36 is disposed on the inner peripheral surface facing the shaft and is divided into two in the axial direction. Further, the leaf springs 37 through which the shaft passes are arranged as bearings at both ends of the core unit 32. Further, a cylindrical case 38 is attached to the outer periphery of the core unit 32 so that the outer peripheral surface of the flange 33 is the same.
As the leaf spring 37 used as the bearing, for example, as shown in FIG. 5, a plurality of ring-shaped portions 37a having different diameters are arranged concentrically and adjacent to each other among the plurality of ring-shaped portions 37a. The ring-shaped portions are connected to each other by a bridge portion 37b provided extending in the radial direction every 180 degrees. Of course, the leaf spring 37 shown here is an example, and can be variously modified as required.

  An inner core 39 that is an iron member is fixed to a portion of the mover 17 that faces the core unit 32 via a spacer 40. The linear actuator 30 of this embodiment configured as described above can be assembled with one touch without using bolts or screws, and the number of work steps can be reduced. In addition, since the leaf spring 37 is used as a bearing, the friction and wear are extremely small as compared to the case where a bearing using sliding or rolling is used, and a (semi-permanent) bearing with no life is obtained. As a result, a highly reliable linear actuator can be obtained.

  FIG. 6 is a perspective view showing a third embodiment of the linear actuator 30 according to the present invention. Here, the same parts as those of the second embodiment are designated by the same reference numerals and the description thereof is omitted. In the present embodiment, the stator 31 includes a cylindrical core unit 32 and a cylindrical flange 33, and a mover (shaft) 17 is inserted through the center thereof. In addition, a coil spring 19 that is an elastic member is disposed at both ends of the core unit 32, and is sandwiched between E-rings 20 that are stopper members fitted to the shaft via spring retainers 21. These points are the same as in the second embodiment.

  The feature of this embodiment is that the permanent magnet 41 is attached to the shaft movable element (shaft) 17 side. Incidentally, in the second embodiment described above, the permanent magnet 36 is attached to the stator 31 side. Also in this embodiment, as in the second embodiment described above, it can be assembled with one touch, and since the leaf spring 37 is used as a bearing, it is compared with the case where a bearing or the like utilizing sliding or rolling is used. As a result, a (semi-permanent) bearing with very little friction and wear can be obtained. As a result, an effect such as a highly reliable linear actuator can be obtained.

  FIG. 7 is a perspective view showing a fourth embodiment of the linear actuator according to the present invention, and FIG. 8 is a sectional view thereof. In this embodiment, the elastic member 19 is a rubber spring 52 having a bellows shape. As the rubber, natural rubber, artificial rubber, synthetic resin having elasticity, and the like can be optimally used.

  When configured as described above, the resonance characteristics different from those of the metal spring can be obtained by the elastic characteristics of the rubber, and in some cases, the stability during the resonance operation can be enhanced.

  FIG. 9 is a perspective view showing a fifth embodiment of the linear actuator according to the present invention, and FIG. 10 is a sectional view thereof. In this embodiment, the elastic member 19 is composed of a gas pressure spring (air spring) 72. The gas pressure spring 72 is a gas-filled bag 73 filled with gas, and has an elastic characteristic different from that of a metal spring or a rubber spring.

FIG. 1 is a perspective view showing an embodiment of a linear actuator according to the present invention. FIG. 2 is a sectional view of the linear actuator. FIG. 3 is a perspective view showing a second embodiment of the linear actuator according to the present invention. FIG. 4 is a sectional view of the linear actuator. FIG. 5 is a perspective view showing a leaf spring used in the linear actuator. FIG. 6 is a perspective view showing a third embodiment of the linear actuator according to the present invention. FIG. 7 is a perspective view showing a fourth embodiment of the linear actuator according to the present invention. FIG. 8 is a sectional view of the linear actuator. FIG. 9 is a perspective view showing a fifth embodiment of the linear actuator according to the present invention. FIG. 10 is a sectional view of the linear actuator. FIG. 11 is an explanatory view showing an example of a conventional linear actuator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Linear actuator 11 Electromagnetic coil 12 Core unit 13 Bearing 14 Flange 15 Stator 16 Iron member (inner core)
17 Mover (shaft)
18 Permanent magnets 19, 52, 72 Elastic member 20 Stopper member (E-ring)
21 Spring retainer
37 Leaf spring (leaf spring bearing)

Claims (6)

A stator having a core unit including an electromagnetic coil and flanges provided at both ends of the core unit and including a bearing;
A mover that has an iron member at least in part, is disposed through the stator, and is supported by the bearing so as to be capable of reciprocating along the axial direction of the stator;
An arc-shaped permanent magnet disposed on the opposing surfaces of the stator and the mover in a state where the magnetic poles are orthogonal to the axial direction;
Elastic members disposed at both ends of the flange;
It consists of a pair of stopper members fixed to substantially both ends of the mover,
A linear actuator characterized in that the outer end of each elastic member is clamped by the stopper member.   2. The linear actuator according to claim 1, wherein the core unit includes a leaf spring-shaped bearing disposed at both ends and penetrating a mover.   3. The core unit according to claim 1, wherein an electromagnetic coil is disposed on the outer peripheral side at the center in the axial direction, and the permanent magnet is disposed by being divided into two in the axial direction. Linear actuator.   The linear actuator according to claim 1, wherein the elastic member is a coil spring.   The linear actuator according to claim 1, wherein the elastic member is a rubber spring. The linear actuator according to claim 1, wherein the elastic member is a gas pressure spring.

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