JPS5825025B2 - linear motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positioning device, and more particularly to a linear motor used in a mechanism for positioning a head to a desired track in a disk file storage device.

In a disk file storage device, in order to obtain the necessary storage capacity, as shown in Fig. 1, a disk 1 is stacked at regular intervals as an assembly 2 (hereinafter referred to as a disk puncture), which is rotated by the same rotation axis, and each side of this disk is Generally, a method is adopted in which the head arm 25 is attached to the carriage 4 in a comb shape so that the head 3 is positioned at the position of the head 3, and the linear motor 5 drives the head arm 25 in a straight line backwards.

An example of the magnetic circuit of a linear motor is shown in Fig. 1, where the magnetic flux generated by the permanent magnet 5 takes a path as shown by the arrow and interacts with the current flowing through the coil 7 inserted into the gap 6. generate force.

In disk files, it is necessary to shorten the access time (the time it takes for the head to move and position itself between tracks) in order to improve the data throughput.

The most direct method is to use the head arm 8 as shown in Figure 1.
This is to shorten the stroke by attaching two or more heads 9, 10 to the head (hereinafter referred to as multi-head).

However, when retracting is performed using this multi-head, the retracting stroke generally becomes longer.

An example is shown in FIG. Here, the head 9 was in the retracted position (position C) for disc pack replacement.
Then, the head 10 is moved to the outermost circumference (position B) of the portion of the disk 11 where recorded information is written, and is positioned at any position between this and the innermost circumference (position A) to record data. Perform playback.

In the case of the dimensions shown in this figure, the access stroke is 257N.
The stroke of the tract is 41 m compared to Il, which means that the stroke of the linear motor is long and large because the retraction is much less frequent than the access.

This tendency becomes more pronounced as the number of heads per head arm increases.

Particularly in the case of large-capacity disk files, the large size of the linear motor is one of the obstacles to speeding up access, so it is disadvantageous to shorten the stroke of the linear motor in this way.

In order to eliminate this drawback, the linear motor of the present invention supports its magnetic circuit on a base via a direct-acting type bearing, and manually or automatically moves the magnetic circuit rearward during tracting.

A detailed explanation will be given below according to examples.

In FIG. 2, the magnetic circuit 26 is slidably supported on the shaft 13 by a direct-acting bearing 12. As shown in FIG.

The shaft 13 is fixed to the base 18 by a support 23.

During retraction, rotation from the disk rotation motor is transmitted to the feed screw 15 via the electromagnetic clutch 14 to move the female screw 24 connected to the magnetic circuit 11.

The feed screw 15 is supported by a rotary bearing on the column 21.

Also, the limit switch (
(not shown) and fixed to the base 18
1. Fix with electromagnetic clutch 16.

At this time, the rail 20 on which the carriage 19 moves is the base 1.
Since it is fixed at 8, it does not affect the positioning accuracy.

Is the weight of the linear motor in this example 25? However, if the present invention is not applied to this and the magnetic circuit of the near motor is lengthened by the retract stroke, the weight will be approximately 40 mm.

As described above, by applying the present invention, it is possible to reduce the weight of a linear motor, which is extremely effective in terms of implementation and maintenance.

In this embodiment, we will discuss a method for automatic retraction, but if the frequency of traction is extremely low, the structure of the shaft 13 and direct acting bearing 12 can be moved manually and clamped in the same manner as in this embodiment. If a separate device is provided, the structure will be simpler than that of this embodiment.

Although the present invention has been described above in the case of magnetic drive, it is generally effective for near motors that perform positioning along a certain axis.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the dimensional relationship in the case of a multi-head, and FIG. 2 is a diagram showing an embodiment according to the present invention. 26 is a magnetic circuit, 12 is a bearing, 13 is a shaft, 1B is a base, 14 is a female screw, and 16 is an electromagnetic clutch.

Claims (1)

[Claims] 1 A moving part with a fixed load, a magnetic circuit that drives the load and the moving part along a predetermined axis, and positions the load at an arbitrary position in a determined moving section, and a magnetic circuit that moves the magnetic circuit. 1. A linear motor comprising: a linear guide means for moving in a direction perpendicular to the direction; and a fixing means for fixing the guide means at a predetermined position.