JPH11285225A - Linear actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain high reliability against noises and moreover low in cost, in conducting control based on the operation detection results of a mover by a detection means. SOLUTION: This linear actuator is provided with a stator 1 formed out of an electromagnet or a permanent magnet, a moving element 2 reciprocatively- supported, involving the permanent magnet or electromagnet, and a detector 39 detecting the operation of the moving element 2, and a controller for controlling power supply to the coil of the electromagnet based on the output of the detector 39. The stator 1 is disposed under the moving element 2, and the controller is disposed under the stator 1. A part to be detected 29 extends downwards from the moving element 2 toward the detector 39 disposed near the controller. The operation of the moving element 2 can be detected without the detector 39 which is disposed at the position of the moving element 2, thus it is possible to reduce a distance between the controller and detector 39.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration type linear actuator capable of obtaining reciprocating vibration.

[0002]

2. Description of the Related Art A vibration type linear actuator is disclosed in Japanese Patent Application Laid-Open No. 2-52692. This is a full-wave rectifier circuit using a linear actuator formed as a single-phase synchronous motor consisting of a mover consisting of a bar-shaped permanent magnet and a stator in which a coil is wound around each piece of a U-shaped iron core. Thus, a DC voltage having a frequency twice as high as the AC frequency is supplied to the coil to cause the mover to reciprocate. In this case, a strong electromagnetic force is required to reciprocate the movable element to generate vibration. However, the movable element is configured as a spring vibration system by supporting the spring, and synchronized with the natural frequency of the spring vibration system. And drive it,
Energy required for driving can be reduced.

[0003] For this purpose, a stator comprising an electromagnet or a permanent magnet, a movable element provided with a permanent magnet or an electromagnet and supported by a spring, and a detecting means for detecting the operation (displacement, speed, acceleration, etc.) of the movable element. And control means for controlling the power supplied to the coil of the electromagnet in accordance with the output of the detection means. In this case, even if the amplitude of the mover changes for some reason, the amplitude change can be detected by the detecting means, and the amplitude can be stabilized by supplying power in accordance with the amplitude change. FIG. 6 shows an example of a linear actuator having such detection means and control means capable of reliably obtaining reciprocating vibration having a stable amplitude. This linear actuator is formed as a drive source for a reciprocating electric shaver, and includes a stator 1, a mover 2, and a frame 3, and is fixed to a chassis 7 together with a battery 8 as a power supply.

The stator 1 includes an E-shaped yoke 10 in which a sintered body of a magnetic material or an iron plate of a magnetic material is laminated,
And a coil 11 wound around a center piece of the chassis body 7 and fixed to the upper end of the chassis body 7. The frame 3 is formed in a U-shaped cross section to which the stator 1 is fixed, and the mover 2 is disposed between both side pieces.

The mover 2 has leaf springs 4 and 4
Are connected to each other so as to be able to reciprocate in the left-right direction in the figure, and a permanent magnet 20 is fixed to the lower surface. Since the permanent magnet 20 is vertically opposed to the stator 1 via a predetermined gap and is magnetized in the reciprocating direction of the mover 2, the permanent magnet 20 varies depending on the direction of the current flowing through the coil 11 of the stator 1. Thus, the leaf spring 4 moves left and right while being bent. By switching the direction of the current flowing through the coil 11 at an appropriate timing, the movable element 2 can perform reciprocating vibration.

A sensor 39 for detecting the operation of the mover 2 is mounted on the frame 3 via a holder 38. The mover 2 detected by the sensor 39 formed of a magnetic sensor or an optical sensor
Of the operation (position, speed, acceleration, etc.) is sent to a control circuit provided with a control circuit mounted on a control circuit board 70 attached to the chassis body 7, and the control circuit outputs By controlling the current flowing through the coil 11 accordingly, the mover 2 is caused to perform an appropriate reciprocating motion.

[0007]

In the above, the sensor 39 is located above the stator 1, and the control circuit board 70 on which the control circuit is mounted is located below the stator 1. Although the sensor 39 and the control circuit board 70 are connected by leading the lead wire 79, when the long lead wire 79 is routed in this way, there is a high possibility that a malfunction will occur due to noise. Also, for the sake of assembly, the connection must be made via a connector 78, and the lead wire 79 must be connected.
And the cost of the connector 78 is high.

The present invention has been made in view of the above points, and an object of the present invention is to perform control based on a detection result of the operation of a mover by a detecting means.
It is an object of the present invention to provide a linear actuator which has high reliability against noise, is low in cost, and can be assembled with high accuracy.

[0009]

According to the present invention, there is provided a stator comprising an electromagnet or a permanent magnet, and a movable member having a permanent magnet or an electromagnet and supported reciprocally. A detection means for detecting an operation; and a control means for controlling power supplied to a coil of the electromagnet in accordance with an output of the detection means, wherein a stator is disposed below the mover, and The linear actuator having the control means disposed on the side thereof is characterized in that the detected part extends downward from the mover toward the detection means disposed near the control means.

[0010] By extending the portion to be detected downward from the mover, the operation of the mover can be detected without disposing the detecting means at the position of the mover. The distance to the detection means can be shortened, and a long lead wire on which noise is liable to be attached is not required. It is preferable that the detecting means and the control means are respectively attached to a chassis body to which the stator is fixed.

The detection means is arranged on the side of the stator, so that the dead space can be effectively used. It is preferable that the chassis is provided with a positioning portion of the detecting means near the stator fixing portion. The detecting means is preferably directly connected to the circuit board in the control means, and in this case, the circuit board in the control means is preferably such that the connecting portion of the detecting means extends upward. It is also preferable to connect the tip of the lead terminal derived from the detecting means to the detecting means connecting portion of the circuit board.

In the case where the stator is provided with an electromagnet, the terminal of the coil of the electromagnet may be connected to the circuit board of the control means via a positioning portion provided on the chassis. A tapered hole through which the coil terminal is inserted can be suitably used for the positioning portion.

[0013]

FIG. 1 shows an example of an embodiment of the present invention.
3 to FIG. The illustrated linear actuator formed as a reciprocating vibration source for a reciprocating electric shaver includes a stator 1
And a movable element 2 (two movable elements 21 and 22 in the figure) and a frame 3, and are disposed on an upper end portion of a chassis body 7 to which batteries 8 and 8 as power sources are fixed on one surface. Has been established.

The stator 1 includes an E-shaped yoke 10 in which a sintered body of a magnetic material or an iron plate of a magnetic material is laminated,
And a coil 11 wound on a central piece of the yoke 10. The engagement walls 71, 71 projecting upward from the widthwise center of the upper end of the chassis body 7 and the outer surface of the yoke 10 engage the chassis body 7. It is fixed to. And the stator 1 has a section U
A frame 3 formed in a character shape is fixed.

Each of the two types of movers 21 and 22 has a back yoke and a permanent magnet (not shown) fixed to the lower surface side. The permanent magnet and the permanent magnet are provided on each lower surface of both side pieces. In the figure, reference numeral 24 denotes a connecting portion provided integrally with the driven body 23 and connected to the inner blade of the reciprocating electric shaver. The mover 22 is disposed between both side pieces of the mover 21 and has a connecting portion 24 protruding upward from an upper surface opening of the mover 21.

Both ends of the movers 21 and 22 are connected to the frame 3 via leaf springs 4 and 4. The leaf spring 4 here has an upper end fixed to the frame 3 via the support plate 40 and a lower end attached to the movers 21 and 22.
2 and includes a central leaf spring 41 connected to the mover 22 and a pair of left and right leaf springs 42 connected to the mover 21. Both movers 2
Numerals 1 and 22 are supported by being suspended from the frame 3.

In the linear vibration motor configured as described above, the permanent magnet provided on the mover 2 is vertically opposed to the stator 1 via a predetermined gap.
Since the magnet is magnetized in the reciprocating direction of the mover 2, the leaf spring 4 is moved in accordance with the direction of the current flowing through the coil 11 of the stator 1.
Is moved right and left while bending, and the movable element 2 can be caused to reciprocate by switching the direction of the current flowing through the coil 11 at an appropriate timing.
Further, since the arrangement of the magnetic poles of the permanent magnets provided on the mover 21 and the arrangement of the magnetic poles of the permanent magnets provided on the mover 22 are reversed, the two movers 21 and 22 have a reciprocating vibration having a phase difference of 180 °. It is intended to do.

The switching of the current direction is effected in accordance with the output of a sensor 39 which is a means for detecting the operation of the mover 2. The sensor 39 is formed by an optical sensor and It is arranged in. That is, the mounting portion 72 is projected upward from the upper end of the chassis body 7 and the sensor 39 is fitted into a recess provided on one surface of the mounting portion 72 at a position adjacent to the engaging wall 71 as shown in FIG. By locking the hook 73 of the mounting portion 73 to the sensor 39, the sensor 39 is fixed, and at the same time, the positioning of the sensor 39 in the vertical and horizontal directions and the depth (the horizontal direction in FIG. 4) is performed.

The control circuit board 70 fixed to the rear surface of the chassis 7 has a connecting portion 75 extending upward along the rear surface of the mounting portion 73. The lead terminal 77 protruding from the back surface is directly connected to the connection part 75. At this time, the sensor 39 is not in contact with the surface of the connecting portion 75, and the hole through which the lead terminal 77 is inserted in the mounting portion 72 may have a sufficient inner diameter. The mechanical stress caused by the connection with the lead 75 is absorbed by the lead terminal 77.

By the way, the lateral position of the stator 1 on which the sensor 39 is arranged depends on the structure of the linear actuator.
Since the position is a dead space, it is not necessary to secure a new space for arranging the sensor 39 at this position. In addition, the engagement wall 71 for positioning and fixing the stator 1 and the sensor 39 Mounting part 72 for holding
Since both are provided on the chassis body 7 and both are located adjacent to each other, the relative positional accuracy is very good.

The terminal of the coil 11 in the stator 1 is also connected to a control circuit board 70 through a positioning hole 77 formed in the chassis 7 as shown in FIG. The connection to the control circuit board 70 can be made accurately and easily. In particular, if the hole 77 is formed in a tapered shape as shown in FIG. It will be easier.

[0022]

As described above, according to the present invention, a stator comprising an electromagnet or a permanent magnet, a movable member having a permanent magnet or an electromagnet and supported reciprocally are provided. Detecting means, and control means for controlling the power supplied to the coil of the electromagnet in accordance with the output of the detecting means, wherein the stator is disposed below the mover, and the lower side of the stator In the linear actuator in which the control means is disposed, the detected part extends downward from the mover toward the detection means disposed in the vicinity of the control means. It is possible to detect the operation of the mover without disposing the detecting means at the position, and it is possible to shorten the distance between the control means and the detecting means, and therefore, to provide a noise-resistant and highly reliable one. Obtainable. In addition, since long lead wires and connectors are not required, costs can be reduced.

It is preferable that the detecting means and the control means are respectively mounted on a chassis body to which the stator is fixed. It can be assembled with high accuracy based on the chassis body. In addition, the detection means is arranged on the side of the stator, so that the dead space can be effectively used, and the linear actuator can be reduced in size.

If the above-mentioned chassis is provided with a positioning portion of the detecting means near the stator fixing portion,
It is easy to increase the relative position accuracy between the detection means and the stator. It is preferable that the detecting means is directly connected to the circuit board in the control means, so that a preferable result can be obtained in terms of cost and reliability.

At this time, if the circuit board of the control means is such that the connection means of the detection means is extended upward, it is not necessary to provide a separate board for the sensor, and the cost can be reduced. The connection between the detection means and the connection portion is such that the stress applied to the sensor can be absorbed by the lead terminal by connecting the tip of the lead terminal derived from the detection portion to the connection portion.

When the stator is provided with an electromagnet, the terminal of the coil of the electromagnet is connected to the circuit board of the control means via a positioning portion provided on the chassis body, so that assembly is simplified. be able to. In particular, if a tapered hole through which the coil terminal is inserted is used as the positioning portion, the assembly becomes simpler and more reliable.

[Brief description of the drawings]

FIG. 1 is a perspective view of an example of an embodiment of the present invention.

FIG. 2 is a cutaway side view of the same.

FIG. 3 is a side view of the same.

FIG. 4 is a cross-sectional view of the sensor mounting portion according to the first embodiment.

FIG. 5 is a view showing a connection part of the coil terminal according to the first embodiment;
(b) is an exploded sectional view in different examples.

FIG. 6 is a rear view of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 2 Mover 3 Frame 29 Detected piece 39 Sensor 70 Control circuit board

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shoji Nakamura 1048 Kadoma Kadoma, Osaka Pref.Matsushita Electric Works, Ltd.

Claims (9)

[Claims] A stator comprising an electromagnet or a permanent magnet;
A movable element provided with a permanent magnet or an electromagnet and supported reciprocally; detecting means for detecting the operation of the movable element; and controlling power supplied to a coil of the electromagnet in accordance with an output of the detecting means. A linear actuator in which the stator is disposed below the mover and the control means is disposed below the stator. A linear actuator characterized in that a portion to be detected extends downward from a mover toward the movable actuator. 2. The linear actuator according to claim 1, wherein the detection means and the control means are respectively mounted on a chassis body to which the stator is fixed. 3. The linear actuator according to claim 1, wherein the detecting means is provided on a side of the stator. 4. The linear actuator according to claim 2, wherein the chassis body is provided with a positioning portion of the detecting means near the fixed portion of the stator. 5. The linear actuator according to claim 2, wherein the detection means is directly connected to a circuit board in the control means. 6. The linear actuator according to claim 5, wherein the circuit board in the control means has a detection means connection portion extending upward. 7. The linear actuator according to claim 5, wherein a tip end of the lead terminal derived from the detecting means is connected to a detecting means connecting portion of the circuit board. 8. An electromagnet is provided on the stator, and a terminal of a coil of the electromagnet is connected to a circuit board of the control means via a positioning portion provided on the chassis body. 8. The linear actuator according to any one of items 2 to 7. 9. The linear actuator according to claim 8, wherein the positioning portion is a tapered hole through which the coil end is inserted.