JPS6260909B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voice coil motor type parallel linear actuator that is compact and easy to assemble.

Voice coil motors, in which a coil is inserted into a gap formed in a magnetic circuit and movement and positioning are performed by controlling the coil current, are widely used in various technical fields. In particular, in the field of magnetic disk drives, high-speed, high-precision voice coil motor type actuators are used to position magnetic heads on concentric recording tracks on rotating magnetic disks. FIG. 1 shows the concept of a magnetic disk device and the configuration of a conventional voice coil motor type linear actuator for positioning a magnetic head.

A magnetic head 2 placed on a magnetic disk 1 is fixed to a movable carriage 4 via a head arm 3. The actuator for driving the carriage 4 is composed of a cylindrical coil 5 whose one end is fixed to the carriage 4, and a magnetic circuit 7 having an annular gap 6 that engages the coil 5. A magnetic disk actuator is required to move the magnetic head from one track to another within a short period of several milliseconds, and to have the magnetic head follow the center position of a predetermined track with an accuracy of several micrometers. be done. For this purpose, it is necessary to make the movable body as light as possible and to raise the mechanical resonance point of the movable body.

By the way, with improvements in magnetic recording technology and positioning technology, the storage capacity per spindle has increased dramatically, and magnetic disk devices with a capacity of 1 gigabyte per spindle have even appeared. In such a large-capacity device, if one actuator is used to input and output information, the throughput decreases, which hinders the efficient operation of the computer system. Therefore, multiple actuators are arranged and each actuator stores data. A method of sharing the capacity began to be used. Such a parallel type actuator is shown in Japanese Patent Laid-Open No. 54-66413. This is an actuator made up of a cylindrical coil 5 and a magnetic circuit 7 having an annular gap 6 as shown in FIG. 1, which are stacked and arranged in parallel. Since the magnetic circuit 7 is cylindrical, it is difficult to make it thinner and there is a limit to its miniaturization; and since the guide mechanism is arranged below the carriage 4, it is difficult to stack three or more sets; Since the carriage 4 and the guide mechanism are complicated, it is difficult to create a simple structure.

In order to solve these drawbacks, the present invention arranges a pair of flat yokes facing each other, arranges a pair of permanent magnets on the facing surfaces of each yoke, and makes the pair of air gaps by facing each other. A set of linear actuator assemblies constructed by inserting a rectangular ring coil into the gap is stacked in multiple stages to construct parallel linear actuators that can each be driven independently. The purpose is to provide a small parallel linear actuator that can be easily made thin and stacked in multiple stages.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a side view of one embodiment of the present invention,
Reference numeral 11 denotes a movable carriage, 12 a head arm attached to the distal end of the carriage, and 13 a bobbin which holds a coil 14 and is fixed to the carriage 11. Reference numeral 15 denotes a flat yoke, with a pair of yokes 15 and 15' facing each other, and a pair of permanent magnets 16 and 17 and 16' and 1 on each opposing surface.
7' and are arranged to face each other to form a pair of gaps 18 and 19. Permanent magnet 16,1
The direction of the magnetic poles of permanent magnets 16, 16' and 17, 17' is perpendicular to the opposing surface, and the direction of the magnetic poles of permanent magnets 16, 16' and 17, 17' are reversed, for example, in the direction of the arrow shown. One approximately quadrilateral circular coil 14
It engages with the pair of gaps 18 and 19 to generate a driving force.
FIG. 2 shows a case in which a carriage 11 equipped with three arms 12 and a set of magnetic circuits having a pair of air gaps 18 and 19 are stacked in three stages. It is clear that the number of stages used does not limit the scope of the present invention.

FIG. 3 is a detailed diagram of a magnetic circuit configuration according to an embodiment of the present invention. Yokes 15', 1 other than the bottom yoke 15 and the top yoke (not shown)
5'', ...... hold a pair of permanent magnets 16, 17, 16', 17' on the upper and lower surfaces respectively, and are fixed only to the magnetic circuit housing 20, and both sides thereof are opened to form an open window. 101. On the side plates 21, 22, a pair of rails 23, 24 for guiding the movement of the carriage 11 are arranged in parallel with the yokes 15, 15', 15'', etc., and open windows 101 of the magnetic circuit. and are arranged in multiple stages corresponding to the stacked carriages.

FIG. 4 is a detailed view showing the structure of the carriage and bobbin. The carriage 11 has a long arm 25
and short arm 26, and a connecting member 27 that connects them.
It is composed of a U-shaped body 102 formed in a roughly U-shape with
A bobbin 13 is coupled to the rear surface. Long arm 25
has a pair of bearings 28 and 2 at the base and tip, respectively.
9 engages with the rail 23 through open windows 101 formed on both sides of the magnetic circuit;
4 and is arranged to engage through the open window.
The short arm 26 has elasticity and presses the carriage 11 against the rail 23 when the bearing 30 engages with the rail 24, thereby enabling highly accurate guidance of the carriage. The bobbin 13 is arranged between the long arm 25 and the short arm 26. A pair of sides 31 and 32 of a quadrilateral annular coil 14 fixed to the tip of the bobbin 13 engage with a pair of gaps in the magnetic circuit to generate a driving force.

As described above, there is a magnetic circuit consisting of two pairs of flat permanent magnets, a pair of flat yokes, and a pair of air gaps formed by these, and a quadrilateral ring coil that engages with the air gaps. , a roughly U-shaped carriage (U
A pair of actuator assemblies, consisting of a pair of rails parallel to the yoke and placed on either side of the air gap, guide the movement of the carriage, in an open window formed on each side of the magnetic circuit. Two U-shaped arms can be mounted compactly, and the U-shaped
Since the spring force of the font itself is used, a precision guide mechanism can be easily constructed. Therefore, compared to conventional equipment,
It is possible to significantly reduce the thickness. Therefore, by stacking these actuator assemblies in multiple stages, parallel linear actuators that can each be driven independently can be constructed in a compact and simple manner. Furthermore, it is possible to easily configure three or more sets of multi-stage actuators, which has been difficult in the past. Furthermore, the coil, bobbin,
Because the carriage is arranged, vibrations excited by access operations are small and rigidity in the direction of movement is high. Therefore, high-speed and highly accurate positioning is possible, and even when a plurality of actuators are driven simultaneously, there is almost no influence of mutual interference.

By using the parallel linear actuator of the present invention, which has a small and simple configuration, it is possible to significantly downsize a multi-positioner magnetic disk device equipped with a plurality of positioners. Furthermore, since it is possible to stack a large number of actuator assemblies, which has been difficult in the past, by using such multi-stage parallel actuators, it is possible to improve the throughput of the magnetic disk device. Furthermore, in response to the increase in the capacity of magnetic disk devices, it is possible to increase the number of stages, and it is possible to realize a large-capacity magnetic disk device without reducing throughput.

It goes without saying that the present invention is applicable not only to the technical field of disk devices but also to a wide range of technical fields requiring parallel actuators.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional magnetic disk, FIG. 2 is a side view of an embodiment of the present invention, FIG. 3 is a perspective view of the magnetic circuit portion of FIG. FIG. 1...Magnetic disk, 2...Magnetic head, 3...
...head arm, 4...carriage, 5...coil, 6...gap, 7...magnetic circuit, 11...carriage, 12...head arm, 13...bobbin, 14...coil, 15, 15'... yoke,
16, 16', 17, 17'...Permanent magnet, 18,
19...Gap, 23,24...Rail, 25...
Long arm, 26...Short arm, 28, 29,
30...Bearing.

Claims (1)

[Scope of Claims] 1. A magnetic circuit housing is constituted by a back plate and a side plate, one end of a flat yoke is fixed to the back plate in parallel in multiple stages with an air gap between them, and two Permanent magnets are held one by one, and the permanent magnets are arranged so that the direction of the magnetic pole of the permanent magnet is in the thickness direction of the yoke, and the magnetic flux passing through each hole of adjacent permanent magnets on the surface of the yoke is in the opposite direction. and a fixed side magnetic circuit mechanism section consisting of rails arranged in multiple stages in parallel with the yoke, and a long arm and a long arm arranged on the side plate of the magnetic circuit housing so as to surround the quadrilateral annular coil. It is formed into a U-shape by a short elastic arm and a connecting member that connects them, and a head arm is connected to the front side of the connecting member, and a bobbin for fixing the coil is connected to the rear side of the connecting member. a carriage mechanism section on the movable side in which a pair of bearings are arranged at the base and a tip end of the short arm, and a pair of bearings also arranged at the tip end of the short arm; and a permanent carriage mechanism section of the magnetic circuit mechanism section. A parallel linear actuator, wherein the annular coil is inserted between magnets, and the long arm and the short arm are movably engaged with the rail.