JP2598841Y2 - Magnetic head drive - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head driving device, for example, when used as various actuators such as a magnetic head positioning device for positioning a magnetic head with respect to a magnetic recording medium of a magnetic disk. And a magnetic head device capable of generating a substantially constant driving torque.

[0002]

2. Description of the Related Art Conventionally, a configuration as shown in FIG. 4 has been known as a configuration for positioning a magnetic head with respect to a magnetic recording medium of a magnetic disk. That is, FIG.
(A) is a plan view showing a main part of a conventional magnetic head device,
FIG. 4B is a cross-sectional view taken along the line XX of FIG.

In both figures, a pair of plate yokes 102, 1
While the spacer 11 is interposed so as to provide a space 104 between the opposing surfaces of the plate 03, the plate-shaped permanent magnet 100 having different magnetic poles (N and S poles) is fixed on the plate-shaped yoke 103 by bonding or the like. With this configuration, a magnetic field that passes through the gap 104 is formed. In the vicinity of this gap 104, FIG.
A head arm 9 is provided so as to be rotatable around a rotation center axis 8 so that the movable coil 50 rotates in the direction of arrow D in (a).

In the above configuration, the magnetic field B formed in the air gap 104 has a wavy magnetic flux distribution as shown in FIG. 5, and the movable range of the movable coil 50 is about 90 to 95% of the maximum magnetic flux density. And the range K in the figure cannot be used.

In order to prevent the rising of the movable coil from becoming gradual in the range K, various measures have conventionally been taken, such as the shape of a plate-like permanent magnet and the control of energizing conditions to the movable coil.

FIG. 6 is a plan view showing a main part of a conventional magnetic head device, and shows a conventional configuration example in which the above measures are not required. In this drawing, a head arm 9 is rotatably supported on a center shaft 8 and
At one end of the head arm 9, a magnetic head 10 for tracing on a magnetic disk 110 constantly rotating at a high speed is provided, and at the other end, a hollow movable coil 50 is provided. The movable coil 50 is an arc-shaped permanent magnet 11.
The head arm 9 is driven and stopped at a desired position by a predetermined energization of the movable coil 50 in such a manner that the head arm 9 is moved in an arc shape in a direction indicated by an arrow D in a gap sandwiched between the arc-shaped stators 112 and 114 to which the fixed members 3 and 115 are fixed. I am trying to do it.

[0007]

However, according to the former magnetic head driving device, since there is a range K that cannot be involved in moving coil driving as described above, the ineffective portion of the permanent magnet increases, In order to make the torque constant in the operating range, it is not possible to make the magnetic flux density uniform, and further, it is necessary to take various measures such as preventing the rising of the movable coil from becoming gentle.

In the latter magnetic head driving device, an arc-shaped permanent magnet and an arc-shaped stator are required, so that the manufacturing cost is increased, and the number of turns and the shape of a movable coil that rotates in the arc-shaped stator are increased. There are problems such as restrictions.

Therefore, the magnetic head driving device of the present invention has been made in view of the above-mentioned circumstances, and the purpose is to make the driving torque constant over the entire movable range of the magnetic head arm, and at the same time, inexpensive and inexpensive. An object of the present invention is to provide a magnetic head drive device that can be configured to be thin.

[0010]

In order to solve the above-mentioned problems and achieve the object, a magnetic head driving device according to the present invention has the following arrangement. That is, a magnetic head drive device comprising a magnetic head at one end, a movable coil at the other end, and a head arm rotatably supported on a base, and a magnetic flux generator for the movable coil. hand,
The magnetic flux generating portion is formed by a plate-shaped permanent magnet having a different magnetic pole on an opposing surface, and a pair of joints having a substantially arcuate shape that is located at a substantially central portion with respect to the opposing surface of the plate-shaped permanent magnet and rotates along with the rotation of the head arm. A pair of movable coils is provided on the head arm with a rotation range separated from the head arm, and is inserted into one of the yoke.

Preferably, a pair of magnetic flux generating portions are provided so as to overlap each other, and a pair of movable coils are provided on the head arm with a rotation range separated from the overlapping yoke.

[0012]

According to the above construction, a magnetic head is provided at one end, and a set of movable coils is separated at a rotation range at the other end and inserted into a yoke, and is rotatably supported on a base. When a predetermined current is supplied to the movable coil of the head arm, the magnetic flux acts on the movable coil without being affected by a change in the magnetic flux density from the magnetic flux generating section, and thus the drive torque of the head arm acts to be constant.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the magnetic head driving device according to the present invention will be described below with reference to the accompanying drawings. First,
FIG. 1 is a diagram schematically showing the configuration of the magnetic head driving device according to the first embodiment, and similarly showing the magnetic flux distribution of the magnetic field B from the magnetic flux generating unit at corresponding positions.

In the figure, as a magnetic flux generating portion having a magnetic flux distribution as shown in the figure, a central portion thereof is located on the opposing surface of the plate-like permanent magnet 1 having different magnetic poles (N, S) on the opposing surface and will be described later. A pair of yoke 2 and 3 having an arc shape along the turning operation of the head arm is fixed.
With this configuration, the magnetic flux generated from the plate-shaped permanent magnet 1 passes through the yoke 2 and 3 as shown in the drawing, and the magnetic field B represented by the curves H1 and H2 is generated in the gap 4. . This magnetic field B is centered on the plate-like permanent magnet 1,
Since it becomes weaker as it gets farther, it becomes symmetrical curves H1, H2 with respect to the plate-shaped permanent magnet 1, and the yoke 2,
3 at each terminal site L. With respect to the yoke 3 of the magnetic flux generating unit configured as described above,
6 is fixed to the head arm so as to be movable in the direction of arrow D so as to form a clearance 7.

In the above configuration, when a predetermined current is supplied to the movable coils 5 and 6, the moving distance x is plotted on the horizontal axis, and the generated torque T is plotted on the vertical axis, as shown in the dynamic characteristic diagram of FIG. As described above, in the range in which the movable coil 5 is located in the range indicated by the above-described curve H1, the relationship of F = KIB (where K is a coefficient, I is a conduction current, and B is a magnetic flux density) From the curve F1 to the curve F1.

On the other hand, in the range where the movable coil 6 is located within the range indicated by the above-mentioned curve H2, the change is made as shown by the curve F2. However, the movable coils 5 and 6 are integrally fixed. The resultant force F in the head arm is substantially linear when F2 is added to F1.

From the above, the entire range of movement of the head arm L
Can be driven such that the driving torque is constant.

FIG. 3A is a plan view showing a main part of the magnetic head driving device having the structure described above. In the figure, a magnetic head 10 is fixed at one end and a head arm 9 to which the above-mentioned movable coils 5 and 6 are fixed at the other end is provided around a rotation center axis 8 suspended from a base (not shown). ing.

On the other hand, the plate-shaped permanent magnet 1 having different magnetic poles (N, S) on the opposing surface to form a magnetic flux generating portion has a fan shape as shown in FIG. A shock absorbing member such as a rubber plate 12 is provided so as to absorb shock when the movable coils 5 and 6 are moved and come into contact with the permanent magnet 1.

The yoke 2, 3 has a fan-shaped arc shape as shown in the figure, and each movable coil 5, 6 has an arrow D1,
The configuration is such that the above-described clearance 7 can be always maintained when rotating in the direction D2. Further, spacers 11 are fixed to both end portions of the yoke 2 and 3, so that the spacers can be fixed to the base using bolts or the like penetrating the spacers 11.

Next, FIG. 3B is a schematic view according to a second embodiment of the present invention. In this drawing, the same components as those in the first embodiment described above are denoted by the same reference numerals as those in the first embodiment, and description thereof will be omitted, and different portions will be described. In this figure, the fundamental difference from the first embodiment is that two sets of magnetic flux generating sections (indicated by reference numerals A and B in the figure) are provided so as to overlap each other.

The yoke 3A, 2
The head arms are driven by allowing the movable coils 5 and 6 to rotate as described above with respect to the portion where B overlaps.

Therefore, according to the configuration of the second embodiment, the driving force can be doubled because two magnetic flux generating units can be used. In addition, a simple configuration in which one set of movable coils is provided separated by a rotation distance and inserted into the yoke is sufficient, so that it is possible to reduce the cost and thickness.

[0024]

As described above, according to the magnetic head drive device of the present invention, the drive torque is constant over the entire range of movement of the arm on which the magnetic head is provided, and the magnetic head drive can be configured inexpensively and thinly. An apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a configuration of a magnetic head driving device according to a first embodiment, in which a magnetic flux distribution of a magnetic field B from a magnetic flux generating unit is shown at a corresponding position.

FIG. 2 is a dynamic characteristic diagram.

FIG. 3 (a) is a plan view of a main part of FIG. 1; FIG. 4B is a diagram schematically illustrating a configuration of a magnetic head driving device according to a second embodiment.

FIG. 4A is a plan view showing a main part of a conventional magnetic head driving device. It is sectional drawing in the XX arrow of (b), (a).

FIG. 5 is a magnetic flux distribution of a conventional magnetic head driving device.

FIG. 6 is a plan view of a main part of a conventional magnetic head driving device.

[Description of sign]

1 ... plate-shaped permanent magnet, 2 ... yoke, 3 ... yoke, 4 ... gap, 5
.. Movable coil, 6 movable coil, 8 central axis, 9 head arm.

Claims (2)

(57) [Scope of request for utility model registration] A magnetic head at one end; a movable coil at the other end; a head arm rotatably supported on a base; and a magnetic flux generator acting on the movable coil. A magnetic head driving device, comprising: a plate-shaped permanent magnet having a different magnetic pole on an opposing surface; and a substantially central portion positioned with respect to the opposing surface of the plate-shaped permanent magnet. A pair of yoke having a circular arc shape along the turning operation, and a set of the movable coil is provided on the head arm with a rotation range separated and inserted into one of the yoke. A magnetic head driving device, wherein the magnetic head driving device is in a state. 2. The head arm, wherein two sets of the magnetic flux generating portions are provided so as to overlap each other, and one set of the movable coil is provided on the head arm with a rotation range separated from the overlapping yoke. The magnetic head drive device according to claim 1, wherein: