JPH03293960A - Secondary iron core of linear pulse motor - Google Patents

Abstract

PURPOSE:To prevent the crumbling of the balance of the internal stress of a member thereby improving the operation accuracy of a linear pulse motor by performing both-side etching for a secondary iron core, and forming irregularity equivalent to a magnetic tooth at the rear of a magnetic pole tooth face. CONSTITUTION:In the figure, LAMBDAa is a magnetic pole tooth formed by etching, and LAMBDAb is a groove removed by etching. And a stator not shown in the figure is provided opposite to the magnetic tooth 1a and the groove 1b. In this example, also at the rear of this magnetic pole tooth, a projection 1c and a recess 1d, which are formed in the patterns equivalent to the magnetic pole tooth LAMBDAa and the groove 1b, are provided by etching. Performing the processing equivalent to the magnetic pole tooth also to the rear of the magnetic pole tooth face, the balance of the internal stress inside the secondary iron core shown by an arrow in the figure does not crumble, and as a result, the plane accuracy before the etching can be maintained. Therefore, the magnetic pole teeth are formed at correct pitches, and the operation accuracy of a linear pulse motor can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a secondary core for a linear pulse motor, and more particularly to a method for manufacturing the same.

BACKGROUND OF THE INVENTION In general, linear pulse motors are used to drive a disk carriage in a floppy disk drive. Furthermore, a linear pulse motor is configured to include a primary core having magnetic pole teeth and a winding thereon, and a secondary core having magnetic pole teeth disposed with a certain gap in opposition to the magnetic pole teeth. ing.

Traditionally, the secondary iron core used in linear pulse motors is made by half-etching a predetermined pattern on one side of a ferromagnetic plate material (hereinafter referred to as a plate material) that has been flattened by double-sided lapping, etc. to form magnetic pole teeth at regular intervals. was forming. Since the spacing (pitch) between the magnetic pole teeth is reflected in the movement step of the motor, high accuracy is required.

However, in the conventional secondary core described above, half-etching is performed on only one side of the plate material to form the magnetic pole teeth, so the balance of internal stress caused by the processing in the previous process that the plate material had before etching is There is a drawback that the plate material warps because it collapses between the surfaces where it is applied and the surfaces where it is not.

This will be explained using FIGS. 2 and 3.

FIG. 2 is a sectional view of the plate material before etching. In the figure, the internal stress that the plate material 2 has in the previous process before etching is indicated by the arrow in the figure. When etching was performed on one side to form magnetic pole teeth, the balance of internal stress was lost and the core was warped like the conventional secondary core 3 shown in FIG. 3.

This has the drawback that the magnetic pole teeth are not formed at the correct pitch, which adversely affects the operational accuracy of the linear pulse motor.

OBJECTS OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks, and its purpose is to provide a secondary iron core that can improve the operating accuracy of a linear pulse motor.

Structure of the Invention The secondary core of the linear pulse motor according to the present invention is a secondary core disposed opposite to the primary core of the linear pulse motor, and has a predetermined pattern of grooves on the back surface of the surface facing the primary core. It is characterized by having.

Example Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of a secondary core according to the present invention. In the figure, 1a is a magnetic pole tooth formed by etching, and 1b is a groove portion removed by etching. A stator (not shown) is provided opposite these magnetic pole teeth 1a and grooves 1b.

In this embodiment, convex portions 1c and four portions 1d formed in the same pattern as the magnetic pole teeth 1a and groove portions 1b are also provided on the back surfaces of these magnetic pole tooth surfaces by etching.

In this way, if the back surface of the magnetic pole tooth surface is processed in the same manner as the magnetic pole tooth, the balance of internal stress within the secondary core 1, which is indicated by the arrow in FIG. Accuracy can be maintained. Therefore, the magnetic pole teeth are formed at a correct pitch, and the operational accuracy of the linear pulse motor is improved.

In addition, warpage of the secondary core can be controlled by intentionally changing the etching pattern on the back surface of the magnetic pole teeth to that of the magnetic pole teeth.

For example, depending on the material of the plate material and the state of the previous process, the interval between the recesses may be made different from the magnetic pole tooth surface, or the depth and length may be changed. In this case, if the etching process is performed in several steps and the effect is checked after each etching process, the original planar accuracy can be easily maintained.

Furthermore, by reducing the etching pattern on the back surface of the magnetic pole teeth, the weight of the secondary core can be reduced while maintaining the same strength as when the back surface of the magnetic pole teeth is not etched. for example,
As shown in FIG. 5, convex portions 1 are arranged alternately with magnetic pole teeth 1a.
It is sufficient to provide c.

It should be noted that instead of etching, it is possible to form the magnetic pole teeth etc. by scraping with a cutter, but this is not a good idea as it has some drawbacks in terms of accuracy.

Detailed Description of the Invention As described above, the present invention prevents the internal stress of the plate from becoming unbalanced by performing secondary double-sided etching to form convex portions on the back surface of the magnetic pole teeth, which are equivalent to the magnetic pole teeth.
As a result, the planar accuracy before etching can be maintained.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the secondary core of a linear pulse motor according to an embodiment of the present invention, Fig. 2 is a cross-sectional view showing the state of internal stress in the plate material before etching, and Fig. 3 is a cross-sectional view of the secondary core of the linear pulse motor according to the embodiment of the present invention. 4 is a cross-sectional view showing the internal stress of the secondary core in FIG. 1; FIG. 5 is a cross-sectional view of the secondary core according to another embodiment of the present invention. It is. Explanation of symbols of main parts 1a...Magnetic pole teeth 1b...2111 Part 1C...
・Convex portion 1d...Four parts

Claims (1)

[Claims] (1) A secondary core of a linear pulse motor, which is disposed opposite to a primary core of a linear pulse motor, and has a predetermined pattern of grooves on the back surface of the surface facing the primary core. Iron core.