JPS61273166A - Linear pulse motor - Google Patents

Abstract

PURPOSE:To reduce the size and the thickness of the entire linear pulse motor and to decrease the weight of a movable element by forming the element in a flat plate shape and using a simple ball single row bearing. CONSTITUTION:A movable element 1 made of a flat plate core has movable element teeth of irregular surface along the lateral direction of upper and lower surfaces. A stator 4 has pairs of upper and lower cores 5, two permanent magnets 6 disposed between the cores 5, coils 7A, 7B interposed between the upper and lower cores 5 for generating drive forces, a box-shaped case 8 for containing them and a case retainer 9. The element 1 is telescopically supported through a ball single row bearing 10 to the stator 4. The bearing 10 has a ball 11, a retainer 12, a slider and a retainer spring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a linear pulse motor used for driving a magnetic head, etc.

[Background technology]

Conventionally, magnetic heads used in floppy disk drives (FDD), etc. are driven either by driving the head linearly through a linear conversion mechanism using a rotary step motor, or directly driving the head by a linear pulse motor. Either method is used. However, since the rotary step motor requires a linear translation mechanism, it requires a large number of parts and a large space.

There are two types of linear pulse motors: a round type shown in FIGS. 10 and 11, and a groove type mover shown in FIGS. 12 and 13.

In the round type, a guide shaft 41 is provided at the center of a cylindrical stator 40, and a cylindrical movable element 42 is supported on the guide shaft via a slide bearing 43 so as to be movable forward and backward. The mover 42 includes a permanent magnet 44, a coil 45, and a mover core 4.
6 and 6 are for installation.

In the groove-shaped mover, a stator 50 is provided with a permanent magnet 51, a coil 52, and an iron core 53, and a groove-shaped mover 54 is placed over this. The movable element 54 is supported by the stator 50 by bearings 55 on the inner surfaces of both flanges.

However, these linear pulse motors have the following drawbacks.

The round type shown in FIGS. 10 and 11 is small and can occupy a small space, but requires an expensive slide bearing 43, resulting in high cost. Furthermore, since the movable element 42 includes a coil 45, a permanent magnet 44, and a movable element core 46, the weight of the movable element 42 becomes large, making it unsuitable for high-speed response.

The groove-shaped mover shown in FIGS. 12 and 13 has a coil 52.
Although the permanent magnet 51 and the iron core 53 are provided on the stator 50, since the movable element 54 is groove-shaped, the movable element 54 becomes large and heavy.

As a result, high speed performance cannot be obtained, and the inertia is large, resulting in poor damping characteristics, and the overall size is large, making it impossible to use for floppy disks.

[Purpose of the invention]

The object of the present invention is to provide a linear pulse motor that can be made smaller in size as a whole, has a lighter movable element, has improved high-speed response and damping characteristics, and can be manufactured using low-cost parts. .

[Disclosure of the Invention] The linear pulse smoke of the present invention includes a stator including a permanent magnet, an iron core, a coil, and a case housing these, and a stator that is supported by the stator through a single row ball bearing and is connected to the iron core. It is equipped with a flat plate-shaped movable element that moves forward and backward while maintaining a certain gap.

According to this configuration, the mover is flat and uses a simple single-row ball bearing, so the overall size is reduced.
And it can be made thinner. In addition, since the mover is flat,
The weight of the mover can be reduced.

This enables high-speed response and good damping characteristics.Furthermore, since the bearing is a single row ball bearing, the structure is simple and low cost.

Embodiment An embodiment of the present invention is shown in FIGS. 1 to 8.
In the figure, l is a mover made of a flat iron core,
It has movable child teeth 2 with irregularities along the width direction on the upper and lower surfaces, and grooves 3 are formed on both end surfaces along the longitudinal direction. The stator 4 is sandwiched between 4-fil iron cores 5 arranged in upper and lower pairs, two permanent magnets 6 placed between each pair of iron cores 5, and the upper and lower iron cores 5 to generate driving force. Coil 7A, 7
B, a box-shaped case 8 and a case holder 9 that house these. The mover l is a ball single row bearing 10
It is supported by the stator 4 so as to be freely movable forward and backward. The single-row ball bearing 10 includes balls 11, a retainer 12, a slider 13, and a pressing spring 14. The case 8 presses the upper and lower iron cores 5 with the slider 13 in between from above and below, and the earth wall part or the lower wall is pressed so that the gap g (the gap between the mover 1 and the iron core 5) shown in FIG. 4 is secured. This is because the parts have elasticity. Normally, the gap g is about 0.05 m. The case retainer 9 shown in FIG. 1 serves both of the functions of preventing gaps in the slider 13 and fixing the iron core 5 and the like to the case 8.

The slider 13 has a Vfi 13a on its inner surface, and the ball 11 rolls into contact with the inner surface of the V-groove 3 of the slider 13 and the mover l. Five to fifteen balls 11 are provided. The retainer 12 maintains the distance between the balls 11, and has a hole 15 with an inner diameter slightly larger than the outer diameter of the balls 11.
1, and the balls 11 are housed therein.

The pressing spring 14 presses the slider 13 inward.

Operation: In this linear pulse motor, the movable element 1 is moved in steps by various drive circuits such as 1-phase, 2-phase, and -2-phase, similar to the conventional linear pulse motor.

FIG. 8 shows the operating state of each step in the case of l-phase excitation.
The positional relationship in the tooth row direction between a to 5d and the movable child teeth 2 serving as the magnetic pole teeth of the movable child 1 is, for example, in one stable state of FIG. 5 (same state as FIG. 8(A)). Stator tooth 5
a faces the movable child tooth 2, and the stator tooth 5b faces the movable child tooth 2.
The stator teeth 5c are 174 pinches away from the movable tooth 2 on the opposite side in direction A (1 pitch is adjacent to the movable tooth 2). up to the movable tooth 2), the stator tooth 5d is directed toward the movable tooth 2 in the direction A.
There is a 1/4 pitch shift (1/2 pitch shift in relation to the stator tooth 5C).

Further, magnetic flux GI flows as shown by the dashed line in FIG. 8 due to the permanent magnet 6, and an attractive force acts between the stator teeth 5a to 5d and the movable child teeth 2, so that any of the stator teeth 5a to 5d It faces the movable tooth 2 and is in a stable state. Further, by alternately applying pulses to the coils 7A and 7B, the device operates as shown in FIGS. 8(A) to 8(H). (A) to (H) in the same figure are the operating states of each step in which the pulse period τ is divided into eight.
(G) becomes a stable state. Coil 7A, 7 by pulse
B magnetic flux G2. G3 is shown by a solid thin line, and each part B where the attractive force acts acts in the same direction as the magnetic flux Gl by the permanent magnet 6, so these mainly contribute to the propulsion of the mover 1, and per cycle of the pulse, It can be seen that it advances by one pitch.

That is, when the coil 7^ is set in the non-excited coil B to the energized state from the stable state shown in FIG. 4(A), the movable element advances to the state shown in FIG. 2(C) and becomes stable. Similarly, if coil 7B is de-energized and coil 7A is energized in figure (C), figure (D)
It progresses to state (E) and becomes stable. In the same figure (E), if coil 7A is not energized and coil 7B is energized, then the same figure (F
) to state (G) and becomes stable. If coil 7B is not energized and coil 7A is energized in the same figure (G), then the same figure (
It progresses from H) to (A) in the same figure and becomes stable.

FIG. 9 shows the case of two-phase excitation; in this case, the same figure (B
)(D)(F)(H) becomes a stable state.

When the coil 7A is reversely excited in the same figure (B), it progresses from the same figure (C) to the same figure (D) and becomes stable. Coil 7 in the same figure (D)
When B is reversely excited, it progresses from (E) to (F) in the same figure and becomes stable. When the coil 7A is reversely excited in the same figure (F), it progresses from the same figure CG') to the same figure (H) and becomes stable. Same figure (H
), when the coil 7B is reversely excited, the diagram changes from (A) to (
Proceed to step B) and stabilize.

Driven in this manner, this configuration provides the following advantages. That is, ■ the movable element 1 has a flat plate shape;
Furthermore, since a simple single-row ball bearing 10 is used, the overall size and thickness can be reduced. (2) Since the movable element 1 has a flat plate shape, the weight of the movable element 1 can be reduced, thereby enabling high-speed response. (2) Furthermore, since the movable element 1 is lightweight, damping against sudden stops is small, and seek time can be shortened. FIG. 7 shows the damping characteristics of a conventional movable element with a large mass and this embodiment. ■Since a single-row ball bearing IO is used for the bearing, the structure is simple and low cost, and the gap regulation and assembly method are simple, making it possible to reduce the overall cost compared to conventional bearings. . ■As follows, it becomes a highly efficient magnetic circuit and high output can be obtained. That is, as shown in FIG. 4, due to the difference between the thickness a of the slider 13 and the thickness b of the mover l, a gap g between the mover 1 and the iron core 5 is formed on both sides of the mover 1.
However, since both sides of the mover l are used in this way, it takes up approximately 172 spaces compared to the conventional model that generates driving force from only one side, as shown in the example in Figure 12. Approximately twice as much driving force can be generated. If the space is the same, you can get four times the driving force. ■Push it 1
4 presses the slider 13 to keep the slider 13, mover 1, and ball 11 in close contact with each other, so that a stable gap g is guaranteed and the mover 1 operates smoothly.

Note that the retainer 12 operates as follows. The retainer 12 keeps the distance between the balls 11 constant, but as the balls 11 move due to rotation, the retainer 12 keeps the distance between the balls 11 constant.
Move the same distance as 1.

The ratio of moving distances between the mover 1 and the retainer 12 is 2:1. As shown in FIG. 6A, when the ball 11 rotates about the spherical center 0, if the members 16 and 17 are free, the members 16 and 17 move in opposite directions by a distance l. Similarly, as shown in FIG. 6(B), when the stator 4 is fixed, the ball 11 rolls and moves by a distance Ml, so that the mover 1 moves by 2i.

〔Effect of the invention〕

In the linear pulse motor of the present invention, the mover has a flat plate shape and uses a simple single-row ball bearing, so the entire motor can be made smaller and thinner.

Furthermore, since the movable element has a flat plate shape, the weight of the movable element can be reduced. Therefore, high-speed response is possible, and damping characteristics are good.Furthermore, since the bearing is a single-row ball bearing, the structure is simple and the cost is low.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of one embodiment of the present invention, Fig. 2 is a vertical cross-sectional view thereof, Fig. N43 is a cross-sectional view taken along line mm in Fig. 2, and Fig. 4
The figure is a partial enlarged view of FIG. 3, FIG. 5 is a partial enlarged view of FIG. An explanatory diagram of the operation in the case of excitation, Fig. 9 is an explanatory diagram of the operation in the case of two-phase excitation, Fig. 10 is a sectional view of the conventional example, Fig. 11 is a front view thereof, and Fig. 12 is another conventional example. FIG. 13 is a longitudinal cross-sectional view thereof, and FIG. 13 is a cross-sectional view thereof. 1...Mover, 3...V conductor, 4...Stator, 5...
...Iron core, 6...Permanent magnet, 7A, 7B...Coil, 8...Case, 10...Single row ball bearing, 11.
...ball, 12...retainer, 13...slider,
14... Pressure m mountain Figure 2 Figure 3 Figure 4 Figure fx9 Procedure amendment (September 13, 1985)

Claims (1)

[Claims] A stator consisting of a permanent magnet, an iron core, a coil, and a case housing them, and a flat plate that is supported by the stator through a single row of balls and moves forward and backward while maintaining a certain gap with respect to the iron core. A linear pulse motor with a mover.