JPS63253850A - Linear pulse motor - Google Patents

Abstract

PURPOSE:To obtain high positioning accuracy and stable positioning torque, by arranging two rows of upper yokes in the advancing direction of a moving element and arranging four rows of the same in an orthogonal direction to the advancing direction of the moving element. CONSTITUTION:A stator is provided with a first teeth 11 on the surface of a flat plate lower yoke 7, provided with permanent magnets 4, and 8 pieces of upper yokes 1, arranged in two rows in the advancing direction of a moving element 3 and in four rows orthogonal to the advancing direction of the moving element 3. The yokes C, D are deviated by 1/2 pitches. the yokes E, F are deviated by 1/4 pitches and the yokes G, H are deviated by 3/4 pitches with respect to the reference of the upper yokes A, B. The moving element 3 is provided with 2 rows of second teeth 31 opposing to the first teeth 11. The moving element 3 is driven by repeating 4 processes. At first, the upper yokes A, C and the upper yokes B, D are conducted so that the yokes A, B generate the same power with the magnetic field of the same direction as the magnetic field of the permanent magnet 4. The upper yokes C, D generate the magnetic field of the reverse direction to the magnet, however, they do not generate magnetic force. Next, the upper yokes E, F, C, D are conducted so as to generate the magnetic field whereby a constitution, same as the first arrangement, may be obtained and the stable driving of one pitch may be obtained by the rotation of 4 conversions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a linear pulse motor, and particularly to a small linear pulse motor suitable for linearly moving a head of a disk device or the like.

[Conventional technology]

In a conventional linear pulse motor, as shown in FIGS. 4 and 5, a mover 100 has a flat plate member 101 made of a magnetic material.
A permanent magnet 102 is provided in the center of the magnet, and four rectangular parallelepipeds 103 are integrally provided at the upper part thereof, and each rectangular parallelepiped has a first tooth 104 on its plane.

Rectangular parallelepiped 103 having two rows in a direction perpendicular to the moving direction of the mover
The teeth 104 on the side of the rectangular parallelepiped 103 in the rear row are shifted by 1/2 pitch in the advancing direction (FIG. 5).

The excitation coil 201 is inserted into the rectangular parallelepiped 103 of the mover 100 and wound.

The stator 301 is made of a magnetic material, and has the mover 1 on one side.
The second tooth 302 opposite to the first tooth 104 on the 00 side is
There are rows, and each row on the left and right in the direction of travel is shifted by 1/4 pitch (FIG. 5). Mover 10 for stator 301
A guide 401 that guides the movement of 0 is made of a non-magnetic material combined with a flat plate member 101, and has a first tooth 104 and a second tooth 3.
A bearing 402 is provided to provide a gap between the stator 301 and the stator 301, and is configured to sandwich the stator 301 from the bottom and side surfaces.

[Problem that the invention seeks to solve]

However, the above-mentioned linear pulse motor is
The mover is driven by a magnetic circuit consisting of four rectangular parallelepipeds 103, a permanent magnet 102, an excitation coil 201, and a mover 100 and a stator 301 that integrally couple them as shown in the figure, but in the case of two-phase excitation, a fixed The overlapping state of the tooth 302 of the child 301 and the tooth on the movable element 100 side is shown in Fig. 5(a), (
The states of b), (c), and (d) are reached, and the state shown in Fig. 5 (
In the case of a), the magnetic circuit is formed by the rectangular parallelepiped parts of FIG. 4A and B, and in the case of FIG. In the case of c), see Figure 4C,
The rectangular parallelepiped portion of D constitutes a magnetic circuit, and in the case of FIG. 5(d), the rectangular parallelepiped portion of FIG. 4 B and C constitute a magnetic circuit,
Drive one pitch in the rotation rotation of the conversion.

The magnetic circuit formation can be switched by controlling the excitation (H) coil 201. For example, in the case of FIG. 5(a), the permanent magnet 1 is
In order to generate a magnetic field in the same direction as 02, C and D
Each rectangular parallelepiped 103 side generates a magnetic field in the opposite direction to the permanent magnet 102 and cancels out the magnetic force of the permanent magnet to prevent the formation of a magnetic circuit. Through such control, as shown in FIG. ) to (d), the parts constituting the magnetic circuit are sequentially switched and driven.

In FIG. 5, the rectangular parallelepiped portions constituting the magnetic circuit in each step are circled with symbols A-D.

From these figures, Fig. 5(a) shows the magnetic circuit in a state perpendicular to the direction of movement, Fig. 5(b) shows the magnetic circuit in a state inclined to the direction of movement, and Fig. 5(c) shows the magnetic circuit in the direction of movement. FIG. 5(d) shows a magnetic circuit in a state where the direction is perpendicular to the direction of travel; FIG. Therefore, in each case, forces act on each other in the direction in which the teeth 302 of the stator 301 and the teeth 104 on the movable element 100 side overlap each other due to the suction force, so rotational forces in opposite directions are sequentially exerted, and the movable element 100 performs a meandering motion. When the magnetic circuit is perpendicular to the direction of travel, the direction is perpendicular to the guide, so there is not much rotational force, but when the magnetic circuit is at an angle to the direction of travel, a force is applied between two points. Since the distance is long, the rotational force is magnified compared to the force applied in the perpendicular direction, resulting in a meandering motion. Furthermore, the magnetic circuit length is 1.4 in the magnetic circuit in the state perpendicular to the direction of travel and the magnetic circuit in the state at an inclined angle.
Since there is a difference of about twice as much, the magnetic force of the longer magnetic circuit becomes weaker. Therefore, torque fluctuation occurs, which affects positioning accuracy and the like.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and provide a compact linear pulse motor with a relatively simple mechanism, good positioning accuracy, and high torque.

[Means for solving problems]

The linear pulse motor of the present invention includes a moving element made of a magnetic material having teeth, and a magnetic material having teeth facing the teeth of the moving element and provided with a coil mounting part, and comprising two parts in the moving direction of the moving element. Eight upper yokes are arranged in four rows in a direction perpendicular to the direction of travel of the mover, and magnets are provided between the two rows of the upper yokes in the direction of travel of the mover. The present invention is characterized in that it includes a lower yoke made of a magnetic material that is integrally coupled with an upper yoke, an excitation coil wound around the coil mounting portion, and a guide mechanism that linearly guides the moving element.

[Effect]

In the linear pulse motor of the present invention, an upper yoke for forming a magnetic circuit, a magnet, a lower yoke, an excitation Eik coil, and a guide mechanism are provided on the stator side. They are arranged in two rows and four rows in a direction perpendicular to the moving direction of the slider.

The eight upper yokes in this arrangement utilize each of the four rows in the direction perpendicular to the moving direction of the mover, and sequentially form a magnetic circuit in the driving process, making it possible to create a four-conversion rotation. This allows for more stable driving than before.

〔Example〕

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

FIG. 1 is a partial cross-sectional overall configuration front view showing a small linear pulse motor according to an embodiment of the present invention, and FIG.
It is an exploded perspective view in a figure. Moreover, FIG. 3 shows the driving process.

In FIGS. 1 and 2, an upper yoke 1 made of a magnetic material made of a flat plate member has teeth 11 formed at the tip by metal injection molding, and a coil insertion shaft 12 as a coil mounting portion is formed on the lower surface. There is.

A total of eight upper yokes I are arranged in two rows in the moving direction of the mover and in four rows in a direction perpendicular to the moving direction of the mover. In addition, as will be described later, the upper yoke 1 with the symbols A to 1 (with reference to the teeth 11) has A and B as the base, C and D are 1/2 pinch, and E and F are 1/2 pinch. 4 Pitch, G, and H are configured with a 3/4 pitch shift (3rd
figure).

The excitation coil 2 is made of conductive wire formed into a spiral shape and made of twisted cotton 21.
is inserted into the coil insertion shaft 12 of each upper yoke 1. The mover 3 is made of a magnetic material, and has comb-shaped teeth 31, which are slightly wider than the upper yoke 1, formed by metal injection molding at a portion opposite to the teeth 11 at the tip of the upper yoke l.

The teeth 31 of the mover 3 are formed in two rows corresponding to the number of rows of the upper yoke 1, which is two along the moving direction of the mover.

That is, the mover 3 has two rows of teeth 31 on the left and right sides in the direction of movement, and as will be described later, the teeth 31 are shifted by a pitch of 1/4 (FIG. 3).

Each upper yoke l is integrally connected to a lower yaw 7 provided with a permanent stone 4 via a coil insertion shaft 12.

By placing the permanent magnet 4 at the vertical center of the lower yoke 7 in the moving direction of the moving element, a magnetic circuit is formed with the moving element 3 via the upper yoke 1.

On the stator side, eight upper yokes l having teeth 11 are provided on the upper surface of a flat lower yoke 7 made of a magnetic material on which permanent magnets 4 are provided.

A mechanism for guiding the mover 3 is provided on the stator side, and this mechanism has the following configuration.

A plurality of hard balls 5L 52 are provided on the thin plate retainer 5 so as to be located on the outer periphery of the excitation coil 2 and on both sides of the mover 3. Further, the hard ball 51 is located between the guide 61 embedded in the yoke base 6 and the slider 3 to maintain a minute space between the teeth 11 of the upper yoke l and the teeth 31 of the slider 3. . Further, the hard balls 52 sandwich the movable element 3 with optimum pressure by guides 62 located on both sides of the movable element 3 and embedded in the yoke base 6. Yoke input case 6
The guides 61 and 62 are integrally fixed, and the lower yoke 7 is also integrally fixed.

In this way, the small linear pulse motor of this embodiment has the coil insertion shaft 12 in the flat plate member having the first teeth 11 on the plane.
The upper yokes L are arranged in two rows in the moving direction of the mover and in four rows in the direction perpendicular to the mover moving direction. A lower yoke 7 made of a magnetic material is provided with permanent magnets 4 between the two rows to support the individual coil insertion shafts 12 and is integrally connected to the upper yoke 1, and a second yoke 7 facing the first teeth 11 on one surface. teeth 3
1 and a coil insertion shaft 1.
2, a thin plate retainer 5 comprising a plurality of rotatable hard balls 51 and 52 that support the guide mechanism of the slider 3, the bottom and side surfaces of the slider, and the lower yoke 7. the hard ball 51 from the bottom and side of the slider 3.
．． The yoke base 6 is made of a non-magnetic material and supports the lower yoke 7 and the guide 6L 62.

The moving element 3 is driven as shown in the driving process in FIG.
However, unlike the conventional case, the upper yoke 1 is provided in two rows in the moving direction of the mover and four rows in the direction perpendicular to the moving direction. Using this method, a magnetic circuit in a state perpendicular to the moving direction of the mover 3 can be configured in each process sequentially to create a rotation of four conversions.

More specifically, as described above, on the stator side, on the upper surface of the flat plate lower yoke 7 made of a magnetic material and provided with the permanent magnets 4, there are eight upper portions having the first teeth 11 on the plane. A yoke 1 is provided, and the upper yoke 1 extends 2 in the moving direction of the mover.
The upper yokes A, B, and C are arranged in four rows in the direction perpendicular to the movement of the slider.

D, E, F, G, H are C, D based on A and B.
is 1/2 pitch deviation, E and F are 1/4 pitch deviation, G
, H are configured to be shifted by 3/4 pitch, and the mover 3 made of magnetic material
has two rows of second teeth 31 facing the first teeth 11 on one side in the left and right directions in the direction of travel, and is shifted by 1/4 pitch. First, in the case of FIG. 3(a), current is passed through the upper yokes A, C and B, D so that the same force is generated by the magnetic field of A and B in the same direction as the permanent magnet 4. Also at this time,
Since C and D generate a magnetic field in the opposite direction to the magnet, they cancel out the magnetic force of the magnet and no magnetic force is generated. Furthermore, E and F.

G and H form a magnetic circuit using the magnetic force of the permanent magnet 4, but it is stable because the areas of overlapping teeth are the same. Next, in the case of Fig. 3(b), there is E on the E, G side and on the F, H side.
A current is passed so that the same force is generated in the aI field and F in the same direction as the permanent magnet 4.

Further, at this time, since G and H generate an &i field in the opposite direction to the magnet, they cancel out the magnetic force of the permanent magnet 4, and no magnetic force is generated. Furthermore, although A, B, C, and D constitute a magnetic circuit by the magnetic force of the permanent magnet 4, the area of the overlapping teeth is the same, so the circuit is stable. Next, in the case of Figure 3(c), C and D
, Next, in the case of Fig. 3(d), the configuration is changed to the same as Fig. 3(a) and (b) by passing a current through G and H so that a magnetic field is generated. One pinch stable drive can be obtained.

In the conventional one, there are only four rectangular parallelepipeds 103, so 4
Figure 5 (b) when assembling the rotation rotation of conversion
, As shown in (d), two of the four components have no choice but to form a magnetic circuit with an angle inclined to the direction of travel. Fluctuation,
However, the linear pulse motors shown in Figs. 1 and 2 do not have such an effect, and the linear pulse motors shown in Figs.
With the E section yokes 1, four rotations can be realized as shown in FIGS. 3(a) to 3(d).

The small linear pulse motor manufactured by the above method has a step pinch of about 64 μm, a positioning accuracy of ±2 μm, and an output torque of 200 μm.
It is approximately gram-senna meter, which is sufficient for driving recording/reproducing heads, etc., and it has been possible to obtain higher positioning accuracy and stable positioning torque than conventional ones.

In addition, the metal injection molding method has the advantage of making the stencil pins smaller and making simultaneous mass production easier and cheaper.

〔Effect of the invention〕

As explained above, according to the present invention, high positioning accuracy and stable positioning torque can be obtained.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram with a part cut away showing a small linear pulse motor according to an embodiment of the present invention, Fig. 2 is an exploded perspective view thereof, Fig. 3 is a diagram showing the driving process, Fig. 4 5 is an exploded perspective view of a conventional linear pulse motor, and FIG. 5 is a diagram for explaining the driving process thereof. 1... Upper yoke 2... Exciting coil 3... Mover 4... Permanent magnet 5... Retainer 6... Yoke base 7... ... Lower yoke IL 31 ... Teeth 12 ... Coil insertion shaft 51, 52 ... Hard balls 61, 62 ... Guide agent Patent attorney Yoshiyuki Iwasa Figure 1 Figure 2 Figure 4 Figure 3 Figure 5

Claims (2)

[Claims] (1) A slider made of a magnetic material having teeth, each of which has teeth facing the teeth of the slider and a coil mounting portion, each of which has two rows in the moving direction of the slider;
Eight upper yokes are arranged in four rows in a direction perpendicular to the direction of movement of the mover, and magnets are provided between the two rows of the upper yokes in the direction of movement of the mover. A linear pulse motor comprising: a lower yoke made of a magnetic material that is integrally coupled; an excitation coil wound around the coil mounting portion; and a guide mechanism that linearly guides the mover. (2) In the linear pulse motor according to claim 1, the magnet is a permanent magnet, and the guide mechanism is made of a thin plate including a plurality of rotatable hard balls that support the bottom and side surfaces of the slider. A linear pulse motor comprising: a retainer; a guide that supports the movable element from the bottom and side surfaces via the hard balls; and a yoke base made of a non-magnetic material that supports the lower yoke and the guide.