JPH02193560A - actuator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an actuator for obtaining reciprocating motion by energization, and more particularly to a device suitable for a head drive used in a magnetic recording device or the like.

[Conventional technology]

In magnetic recording devices, a device called a voice coil actuator is generally used as a means for moving the magnetic head. As shown in FIG. 3, this consists of a cylindrical permanent magnet 1 whose outer and inner surfaces are magnetized with different polarities,
A yoke 2 that accommodates this permanent magnet 1 and has a cylindrical part 2A at the center, and an air-core coil 4 that moves along the length of the cylindrical part 2 in a gap 3 between the cylindrical part 2A and the permanent magnet 1. It is configured. That is, since the air-core coil 4 is located in the gap 3, that is, in the magnetic field created by the permanent magnet 1 and the cylindrical portion 2A, by energizing the air-core coil 4, it can be moved according to the amount of current.

[Problems to be Solved by the Invention] As described above, conventional voice coil actuators have characteristics such as being able to obtain flat torque characteristics and having good responsiveness, but they do not generate a uniform magnetic field over the entire coil movement section. Therefore, there was a problem in that a large permanent magnet 1 and yoke 2 were required.

In a voice coil actuator, a rare earth magnet is generally used as the permanent magnet 1, but since the unit price per duram is high, there is a problem that an increase in the weight of the permanent magnet 1 directly leads to an increase in cost. In addition, the voice coil actuator is heavy and the air-core coil 4 moves, which requires special consideration for the power supply line.

The present invention was made to solve the above problems, and an object of the present invention is to provide an actuator that is lightweight and provides flat torque characteristics.

(Means for Solving the Problems) An actuator according to the present invention includes two coils that are wound around a plate-shaped core and have different energizing directions, and two different coils that correspond to each other through a side surface of each coil and an air gap. It consists of a polarized permanent magnet.

[Effect]

In this invention, when power is supplied to the two coils in different directions, the permanent magnet side works during the daytime due to the interaction between the current in each coil and the magnetic field created by the corresponding permanent magnet, and the daytime shift corresponds to the amount of current applied. I do.

[Embodiment] An embodiment of the present invention is shown in FIG. In this diagram,
11 is a rotating arm that can rotate in the direction of the arrow, and the head 12
A soft magnetic body 13 made of a high magnetic permeability material such as an iron plate is fixed to the opposite side of the head 12 with screws 14 or the like. Furthermore, permanent magnets 15A and 15B made of rare earth magnets are fixed to the soft magnetic body 13 at intervals. 16
is a core made of laminated electrical steel plates, and coils 17A and 17B are wound around this core 6. Both ends of the core 16 are supported by a support stand 18 and screwed to a base plate (not shown).

FIG. 2 is a diagram for explaining the invention in detail,
Permanent magnets 15A and 15B provided on the day shift side and a soft magnetic body 13 connecting the back surfaces of these permanent magnets 15A and 15B,
The core 16 provided on the stationary side and the two coils 15A and 15B wound around the core 16 are each shown developed in a straight line in a cross section along the moving axis.

Now, when a current flows in the direction shown in the coils 15A and 15B (O indicates a current directed perpendicularly to the page, and ■ indicates a current directed perpendicularly to the page), the coils 15A and 15B flow according to Fleming's law. A downward force is generated on the permanent magnets 15A and 15B, and an opposite reaction occurs on the permanent magnets 15A and 15B. Also, since the force generated is proportional to the size of the current,
It is possible to arbitrarily adjust the force by controlling the amount of current applied.

As is clear from the figure, if the coils 17A and 17B are evenly wound, the permanent magnet 15A is formed.

Uniform thrust characteristics can be obtained regardless of the position of 15B. Further, since the surface of the core 16 facing the permanent magnets 15A and 15B is flat, reluctance torque (generally called cogging) does not occur.

(Effects of the Invention) As explained in detail above, the actuator according to the present invention has two actuators wound around a plate-shaped core, and having two different energizing directions.
The yoke consists of two coils and two permanent magnets of different polarities that correspond to each other through the side of each coil and an air gap, so it can be manufactured at low cost because less expensive permanent magnets are used. Since only a small amount of material is required, the weight of the device can be reduced. Furthermore, since the coil is on the fixed side, no special consideration is required for wiring, and device assembly is easy.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is a diagram for explaining the invention in detail, and FIG. 3 is a sectional view of essential parts of an example of a conventional actuator. In the figure, 11 is a rotating arm, 12 is a head, 13 is a soft magnetic material, 14 is a screw, 15A, 15B are permanent magnets, 16 is a core, 17A, 17B are coils, and 18 is a support base. Figure] 8: Mark stand Figure Figure 8

Claims (1)

[Claims] It consists of two coils that are wound around a plate-shaped core and have different energizing directions, and two permanent magnets with different polarities that correspond to each other through the sides of each coil and an air gap.
An actuator characterized in that the permanent magnet side is movably supported.