JPH0223056A - actuator device - Google Patents

Abstract

PURPOSE:To increase driving torque by forming a magnetic field generating means in such a manner that magnetic flux is cut in a part except in the vicinity of a holding part of a voice coil to a carriage. CONSTITUTION:An actuator device fixes a head assembly to a carriage 11, fixing it onto a moving table 12, and rolls 16, interposing two both side rails 17, are movably provided along the rail in the moving table 12. While a voice coil 13 forms a shape of isosceles triangle with the mounting part serving as the base, providing magnetic coils 14 in a manner wherein they surround inner and outer sides of this voice coil, and it is constituted, generating magnetic flux by a magnet 15 to respectively vertically traverse the other two equal sides of the coil 13 excepting the vicinity of a part fixing the coil 13 to the carriage 11. Then the carriage 11 is moved in a direction of receiving force when an electric current is allowed to flow in the voice coil 13. Because this force is in proportion to a quantity of the coil current, a moving speed of the carriage 11 can be controlled by controlling this quantity of the coil current.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an actuator device for moving a magnetic head in the track direction of a disk memory.

BACKGROUND OF THE INVENTION Some hard disk drive devices are provided with a head feeding mechanism for positioning a magnetic head on a desired track on a disk, and a voice coil motor is used as an actuator for the head feeding mechanism. Generally, a voice coil motor consists of a voice coil and a magnetic field generating section for forming a magnetic field in the voice coil, and the voice coil is usually fixed to a movable carriage that supports a magnetic head assembly. The conventional hard disk head actuator device as described above will be explained with reference to FIG.

FIG. 4 is a sectional view of a part of the head carriage and voice coil motor that constitute the actuator device. The head carriage 31 is movable by rollers 36 along a round bar-shaped rail 35 fixed to the outside. 3
2 is a voice coil wound in a rectangular shape, and the two voice coils are fixed to the - side or helad carriage 31, respectively, and the upper and lower sides pass between the gap parts, and the rectangle surrounded by the voice coil 32. The surface faces the moving direction of the head carriage 31. Further, 34 is a plate-shaped magnet attached to the magnetic core 33, and the magnetic flux generated by the magnet 34 passes through this magnetic core 33 to form a magnetic circuit, and generates a magnetic field in the gap sandwiched by the magnetic core 33. . A conventional actuator device has the above-described structure, and by passing a current through the coil, the coil receives a force from a magnetic field in a direction perpendicular to the surface surrounding the coil, thereby making it possible to move the carriage.

The problem to be solved by the invention is solved by an actuator device having a voice coil 32.
However, since force can only be generated at the gap in the magnetic core,
The remaining two opposing sides of the voice coil were wasted coil windings, which increased the electrical resistance of the voice coil, making it impossible to pass a large amount of current, and the power that could be extracted was weak.

Means for Solving the Problem In order to solve this problem, the present invention provides a magnetic field forming means so that the magnetic flux produced by the magnetic field forming means is cut off by all parts other than the vicinity of the part where the voice coil is held on the carriage.

Effects By configuring as described above, the portion of the coil winding portion other than the attachment portion to the carriage can be efficiently contained in the magnetic field.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. In FIG. 1, reference numeral 11 denotes a carriage on which the head assembly is fixed, and is fixed on a movable table 12. On the movable table 12, rollers 16 are mounted on two rails 1 on both sides.
7 and is movable along the rails. Voice coils 13 are fixed to both sides of the carriage 11, and are shaped like an isosceles triangle with the mounting portion as the base.

Moreover, a magnetic core 14 is formed to surround this shape from the inside and outside.
is provided, and the magnetic flux generated by the magnet 15 attached to the magnetic core 14 is transmitted to the carriage 1 of the voice coil 13.
The structure is such that the other isosceles are perpendicularly crossed except for the vicinity of the holding part to 1.

The operation will be explained below. In FIG. 1, when a current is passed through the voice coil 13, a magnetic field perpendicular to the direction of current flow is generated in the winding portion of the voice coil 13 surrounded by the magnet 15 and the magnetic core 14. A force parallel to the direction acts, and the carriage 11 moves in the direction in which the force is applied.

The force generated by this coil current and magnetic field is proportional to the amount of coil current, so by controlling the amount of current, the moving speed of the carriage 11 can be controlled, and the magnetic head can be moved to a desired position. is possible.

Furthermore, when comparing the cross-sectional view of the actuator device shown in FIG. 2 with the cross-sectional view of the conventional actuator device shown in FIG. Regarding the length and that of the voice coil of the conventional actuator device shown in FIG. 4, it is clear that the coil of this embodiment crosses the magnetic field longer, and the length of the coil winding-circumference is longer than that of the voice coil of the conventional actuator device shown in FIG. The actuator device is shorter. That is, more force can be extracted with the same current, and since the coil length is short (electrical resistance is small), it is possible to flow more current, and even stronger force can be generated.

Note that in the present invention, the shape of the voice coil is not limited to an isosceles triangle (it may also be a trapezoid or a circle as shown in FIG. 3. Here, 43 is a voice coil, 45 is a magnet, 44 is the core.

Effects of the Invention As explained above, the present invention generates magnetic flux by a magnetic field generating means so that when the voice coil attached to the carriage moves, the magnetic flux is cut by a portion other than the vicinity of the portion of the voice coil held by the carriage. As a result, there is less waste in the current flowing through the voice coil.

In other words, it is possible to reduce the coil resistance by shortening the length of the voice coil winding, and to provide an actuator device that has a larger drive torque than conventional actuator devices that have the same length of conductor wound. .

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an actuator device that is an embodiment of the present invention, FIG. 2 is a sectional view of the actuator shown in FIG. 1, and FIG. 3 is a sectional view of an actuator device that is another embodiment of the invention. , FIG. 4 is a sectional view of a conventional actuator device. 13.43...Voice coil 15.45...Magnet 14. 44...core

Claims (1)

[Scope of Claims] A voice coil wound with a conducting wire, a movable carriage that holds the voice coil, and a magnetic field forming means that forms a magnetic flux cut by the voice coil as the carriage moves. An actuator device characterized in that the magnetic field forming means forms a magnetic flux that is cut by all parts of the voice coil other than the vicinity of the part where the voice coil is held by the carriage.