JPS648537B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small and simple parallel linear actuator.

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 moved by a carriage 4 via a head arm 3.
Fixed. The actuator for driving the carriage 4 is composed of a cylindrical coil 6 whose one end is fixed to the carriage, and a magnetic circuit 7 having an annular gap 5 that engages the coil. 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. Ru.
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 Application Laid-Open No. 54-66413.

This is an actuator made up of a cylindrical coil and a magnetic circuit 7 having a cylindrical gap, as shown in FIG. 1, which are stacked and arranged in parallel. However, since the magnetic circuit 7 is cylindrical, it is difficult to make it thinner and there is a limit to its miniaturization, and because the guide mechanism is arranged below the carriage 4, it is difficult to stack three or more sets. The drawbacks were that it was difficult to use, and that the carriage and guide mechanism were complicated, making it difficult to create a simple configuration.

In order to solve these drawbacks, the present invention includes a first magnet assembly in which a pair of flat permanent magnets are connected via a non-magnetic material so that the magnetization directions are opposite to each other; A second magnet assembly in which a magnet is placed on a yoke is used to construct a magnetic circuit in which a plurality of pairs of air gaps with different magnetic field directions are laminated, and a roughly quadrilateral ring coil is inserted into this air gap. A set of linear actuator assemblies constructed by the above method is stacked in multiple stages to form parallel linear actuators that can each be driven independently. The object of the present invention is to provide a small parallel linear actuator that can be easily stacked. 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, in which 8 is a movable carriage, 9 is a head arm attached to the tip of the carriage, and 10 is a bobbin that holds a coil 11 and is fixed to the carriage 8. ing. A pair of permanent magnets 13 and 14 at the lowest stage are attached to a flat plate-shaped yoke 12 to constitute a second magnet assembly, and are fixed to a back plate 15. Although not shown in the figure, the uppermost stage also has a similar structure.

On the other hand, a pair of permanent magnets 13 and 14 facing each other are connected via a non-magnetic material 18 so that their magnetization directions are opposite as shown in the figure, thereby forming a first magnet assembly. , are fixed to the back plate 15 via a non-magnetic material 19. Here, the magnetization directions of magnets 13 and 13' are the same, and magnet 14
The magnetization directions of and 14' are opposite to those of 13 and 13', and the magnetic fields generated in the gaps 16 and 17 are in opposite directions. A generally quadrilateral annular coil 11 is inserted into the pair of gaps 16 and 17, and generates a driving force when energized.

Although FIG. 2 shows a magnetic circuit in the case of a carriage equipped with two arms and three pairs of air gaps, the number of arms mounted and the number of air gaps do not limit the scope of the present invention. is clear. Furthermore, even if the polarity of the magnet in the figure is reversed, the effect remains the same.

FIG. 3 is a detailed diagram of a magnetic circuit configuration according to an embodiment of the present invention. A pair of permanent magnets are held on each of the upper and lower surfaces of the lowermost yoke 12 and the uppermost yoke (not shown), and the back plate 1
It is fixed at 5. A pair of rails 2 are provided on the side plates 20 and 21 to guide the movement of the carriage 8.
2 and 23 are arranged in parallel with the magnet assembly and 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 8 has a long arm 24
and short arm 25, and a connecting member 26 that connects them.
The head arm 9 is connected to the front side of the connecting member, and the bobbin 10 is connected to the rear side of the connecting member. A pair of bearings 27 and 28 are provided at the base and a tip of the long arm 24 to engage with the rail 22, and a pair of bearings 29 provided at the tip of the short arm 25 engage with the rail 23. By pressing the carriage against the rail 22 when engaged, the carriage can be guided with high precision.

The bobbin 10 has a long arm 24 and a short arm 25.
placed between. A generally quadrilateral annular coil 11 fixed to the tip of the bobbin 10 has a pair of sides 3
0 and 31 engage with a pair of gaps in the magnetic circuit to generate a driving force.

As mentioned above, in the top and bottom stages, a second magnet assembly is used in which a pair of permanent magnets are fixed to a yoke, and a first magnet assembly in which a pair of permanent magnets are connected through a non-magnetic material is used. One or more assemblies are arranged to configure a magnetic circuit having a plurality of pairs of air gaps for driving one coil. A generally quadrilateral annular coil that engages with a pair of air gaps in this magnetic circuit, a generally U-shaped carriage that holds this coil in a pair of arms, and a carriage that is arranged parallel to the magnet assembly and on both sides of the air gap. A set of actuator assemblies including a pair of guiding rails can be made significantly thinner.

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. As a result, it is possible to easily configure multi-stage actuators with three or more sets, which was previously difficult, and to reduce the distance between the coils (gap distance),
It is sufficient to reduce the thickness of the magnet in the first magnet assembly located in the middle, and increase the thickness of the magnet in the second magnet assembly located at the top and bottom stages, making it suitable as a magnetic circuit for a multi-positioner.

Furthermore, since the coil, bobbin, and carriage are arranged substantially in line with the plane containing the line of action of the driving force, vibrations excited by the access operation are small and rigidity in the moving direction 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.

As described above, by using the parallel linear actuator of the present invention, which is small and has a 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, it is possible to increase the number of stages in response to an increase in the capacity of a magnetic disk device, 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, 6...coil, 5...gap, 7...magnetic circuit, 8...carriage, 9...head arm, 10...bobbin, 1
1... Coil, 12... Yoke, 13, 13',
14, 14'... Permanent magnet, 15... Back plate, 16, 17... Air gap, 18, 19... Non-magnetic material, 20, 21... Side plate, 22, 2
3...Rail, 24...Long arm, 25...Short arm, 26...Connection material, 27, 28, 29...
... Bearing, 30, 31 ... Coil side (driving force generation side).

Claims (1)

[Claims] 1 A back plate and a side plate constitute a magnetic circuit housing, one end of a flat yoke is fixed in parallel to the top and bottom of the back plate, and two yokes are fixed on each opposing surface of the yoke. One end of a flat magnet assembly, in which the two permanent magnets are connected to the same plane through a non-magnetic material, is placed on the back plate between the permanent magnets held by the yoke. Fixed in parallel in multiple stages with 〓
The permanent magnets are arranged so that the direction of the magnetic poles of the permanent magnets is in the thickness direction of the yoke or the magnet assembly, and the magnetic fluxes passing through the holes of the permanent magnets adjacent to each other on the surface of the yoke or on the same surface are in opposite directions. It is formed into a U-shape by a long arm, a short arm, and a connecting member connecting these so as to surround the magnetic circuit mechanism part on the fixed side and a quadrilateral annular coil, and a head arm is attached to the front of the connecting member. The annular coil is inserted between the movable carriage mechanism section, which is coupled with a bobbin for fixing the coil to the rear surface of the connecting member, and the permanent magnet of the magnetic circuit mechanism section, and the annular coil is inserted between the permanent magnet of the magnetic circuit mechanism section. A parallel linear actuator characterized in that a long arm and a short arm are movably engaged with the magnetic circuit mechanism section.