JPH07288969A - Linear pulse motor - Google Patents

Abstract

PURPOSE:To prevent a mover shaft from being axially magnetized by a permanent magnet by magnetizing a magnetization a permanent magnet, fitted to the inner peripheral surface of a mover core, such that an N pole appears on the outer peripheral surface at one part thereof and an S pole appears on the outer peripheral surface at the other part. CONSTITUTION:When the tip part 30a of a small tooth 30 in a mover core 28b faces the tip part 21a of small tooth 21 in a stator, the tip part 30a of small tooth 30 in a mover core 28a faces the bottom part 21b of the small tooth 21 in stator. Since main flux is generated in the direction perpendicular to the mover shaft 27 from permanent magnets 31a, 31b in the mover 2, the magnetic circuit thereof is formed to pass through the permanent magnet 31a, the mover core 28a, the stator core 10, the mover core 28b, the permanent magnet 31b, the central part of the mover shaft 27, and the permanent magnet 31a sequentially. Since the magnetic circuit does not pass through the entirety of the mover shaft 27, the mover shaft 27 is not magnetized axially. Consequently, leakage flux is suppressed at the end of the shaft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical linear pulse motor.

[0002]

2. Description of the Related Art Conventionally, as a cylindrical linear pulse motor of this type, there is one shown in a vertical sectional view of FIG. In FIG. 6, for example, ten salient poles 11, 12, 13, ..., 20 (only 11 is shown) are radially arranged inwardly on the stator core 10 of the stator 1 at equal pitch angles. Has
A plurality of stator small teeth 2 are arranged on the inner peripheral surface at equal pitches in the axial direction.
1 (tooth tip portion 21a and tooth bottom portion 21b) are provided.
In addition, the stator windings W1, W2, W3, ... W10 are provided to the ten salient poles 11, 12 ,.
(Only W1 is shown) is wound separately.

The stator core 10 has inner diameter portions 10a at both axial ends thereof as fitting holes, and fitting portions 22a and 23b formed on the end brackets 22 and 23 are
While being fitted into the inner diameter portion 10a, it is accommodated in the case 24 by screws (not shown) or the like.

On the other hand, the mover 2 in the stator 1 is supported by the brackets 22 and 23 through the bearings 25 and 26 so that the axis is the same as that of the stator core 10 and is movable in the axial direction. . The mover 2 includes mover cores 28a and 28b on the shaft 27, and mover cores 28a, 28b.
A ring-shaped permanent magnet 29 is sandwiched between b and magnetized in the axial direction. Further, on the outer peripheral surfaces of the mover iron cores 28a and 28b, a plurality of mover small teeth 30 (tooth tip portion 30a and tooth bottom portion facing the stator small teeth 21 and having the same axial pitch are provided. 30b) are arranged, and the arrangement thereof has a relationship as shown in FIG.

That is, the axial length of the permanent magnet 29 arranged on the moving element 2 is determined by the moving element core 28a.
And the movable element small tooth 30 disposed on the movable element iron core 28b has a tooth pitch of 1 in the axial direction.
It is set to deviate by 1/2.

[0006]

However, in such a conventional cylindrical linear pulse motor, the mover iron cores 28a, 28b, the permanent magnet 29 and the shaft 27 in the mover 2 are directly connected to each other. Since it is joined, the shaft 27
When a steel material having magnetism is used as shown in FIG. 7, a magnetic path is formed in the shaft 27, and a part of the main magnetic flux from the permanent magnet 29 leaks into the shaft 27 to be effective. The magnetic flux decreases, the output of the pulse motor decreases, and the shaft 2
There is a problem that magnetic foreign matter adheres to No. 7.

On the other hand, if a non-magnetic material is used for the shaft 27, the shaft 27 cannot be heat treated like a steel material to increase its mechanical strength, and wear occurs due to friction with the bearing portion. There is a problem that the gap between the stator 1 and the mover 2 cannot be kept constant.

The present invention has been made in view of the above points,
It is an object of the present invention to solve the above problems, and to provide a linear pulse motor which can use a magnetic steel-based material or a non-magnetic material for the mover shaft and has little leakage flux to the shaft end.

[0009]

The structure of the present invention for achieving the above-mentioned object has a plurality of salient poles radially arranged toward the inside and has an axis on the inner peripheral surface of the salient pole. A stator having a stator iron core formed with a plurality of stator teeth in a direction, movably supported in the stator in the axial direction, and facing the stator teeth on the outer peripheral surface. , At least a pair of mover iron cores having a plurality of mover small teeth formed at equal pitches in the axial direction and arranged at a predetermined interval in the axial direction, and the pair of mover iron cores having N poles and S poles, respectively. A linear pulse motor including a mover having a permanent magnet for magnetizing the poles is as follows.

(1) The pair of moving element cores are formed in a ring shape, the axis of the moving element is made of a magnetic material or a non-magnetic material, and the permanent magnet is formed in a cylindrical shape, so that the pair of moving elements can move. The outer peripheral surface of one part of the permanent magnet, which is arranged between the child core and the mover shaft and is fitted to the inner peripheral surface of the mover core, is the N pole, and the outer circumference of the other part. It is characterized in that it is magnetized so that the surface becomes an S pole.

(2) In (1), the mover shaft is made of a magnetic material, and the cylindrical permanent magnets form a pair, and are provided between each of the pair of mover iron cores and the mover shaft. Are arranged separately, and one of them is magnetized so that the outer peripheral surface is the N pole, the inner peripheral surface is the S pole, the other outer peripheral surface is the S pole, and the inner peripheral surface is the N pole. Characterize.

[0012]

Since the present invention is constructed as described above, the magnetizing direction of the permanent magnet is perpendicular to the same direction as the conventional moving shaft. Therefore, the mover shaft is not magnetized in the axial direction by the permanent magnet. As a result, the leakage magnetic flux to the shaft end can be suppressed to be small. Further, since a ferrous material having magnetism can be used as the mover shaft, it is possible to configure a linear pulse motor in which the mechanical strength of the mover shaft is increased and the wear resistance of the bearing portion is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be exemplarily described in detail below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of a linear pulse motor of the present invention, and FIG. 2 is a view showing its magnetic flux distribution. In FIG. 1, the same members as those in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 1, the shaft 27 of the moving element 2 is made of a steel material, and a cylindrical permanent member is provided between the outer peripheral surface of the moving element 2 and the inner peripheral surfaces of the pair of ring-shaped moving element iron cores 28a and 28b. The magnets 31a and 31b are arranged so as to be fitted in the magnets 31a and 31b, respectively.
7 and each of the mover iron cores 28a and 28b are integrally fixed. The permanent magnets 31a and 31b are magnetized in the direction perpendicular to the mover shaft 27, and one of the permanent magnets 31a
When the outer peripheral surface is magnetized to the N pole and the inner peripheral surface is magnetized to the S pole, the other permanent magnet 31b, on the contrary, is magnetized to the S pole on the outer peripheral surface and the N pole on the inner peripheral surface. When magnetized, the mover iron core 2
The mover small tooth 30 of 8a is magnetized to the N pole, and the mover small tooth 30 of the mover iron core 28b is magnetized to the S pole.

Ring-shaped members 32 and 33 made of a non-magnetic material are arranged between the pair of mover iron cores 28a and 28b and between the permanent magnets 31a and 31b. The axial length of the ring-shaped member 32 is the same as that of the movable element small tooth 30 disposed on the movable element core 28a.
And the movable element small teeth 30 disposed on the movable element iron core 28b are set to be axially displaced from each other by ½ of the tooth pitch. That is, as shown in FIG.
When the tooth tip portion 30a of the small tooth 8b of 8b faces the tooth tip portion 21a of the stator small tooth 21, the tooth tip portion 30a of the small tooth 30 of the mover iron core 28a is the tooth bottom portion of the stator small tooth 21. 21b is set to face.

On the other hand, FIG. 3 shows an example of the stator iron plate 40 forming the stator core 10 in the case where the number of phases is 5 and the number of stator salient poles is 10. In FIG. 3, salient poles P41, P42, P43, ...
... P50 among salient poles P41, P43, P46, P48
Is a salient pole having a small radius, and salient poles P42, P44,
P45, P47, P49 and P50 are salient poles having a large radius dimension. Further, the salient poles P41, P42, ... P45
And the salient poles P46, P47, ... P50 respectively constitute one salient pole group, and the salient pole 2 having a small radius dimension is used.
And three salient poles with a large radius. Then, the salient poles P41 and P having a small radius dimension in each salient pole group
43 and P46 and P48 form an angle of 72 degrees with each other.

FIG. 4 is a view of the stator small teeth 21 formed when the stator iron plates 40 are stacked while rotating at an angle of 72 degrees from the side of the moving element 2. The black portion (hatched portion) indicates the tooth tip portion 21a, and the white portion (non-hatched portion) indicates the tooth bottom portion 21b. By laminating in this manner, each salient pole 41,
42, ..., 50 has a tooth pitch of 5t ₀ and a tooth width of 2t _0.
Small teeth 21 are formed. Here, t ₀ is the thickness of the iron plate. Moreover, the small teeth 21 formed on the adjacent salient poles are displaced from each other by 2/5 or 3/5 of the tooth pitch, and the stator 1 is wound around the salient poles 11, 12, 13 ,. The wound windings W1, W2, W3, ... W10 form a 5-phase stator. Therefore, the stator 1
Together with the mover 2 constitute a 5-phase hybrid linear pulse motor. In this case, the basic amount of movement for each step is 1/10 of the tooth pitch, that is, t _0/2.

In the moving element 2 as described above, the main magnetic fluxes from the permanent magnets 31a and 31b are generated in the direction perpendicular to the moving element axis 27, so that the magnetic path thereof is the permanent magnet 3 '.
1a, the mover iron core 28a, the stator iron core 10, the mover iron core 28b, the permanent magnet 31b, the central portion of the mover shaft 27, and the path formed through the permanent magnet 31a. The mover shaft 27 is not magnetized in the axial direction. As a result, the leakage magnetic flux to the shaft end can be suppressed to be small.

Further, since a ferrous steel material having magnetism can be used as the mover shaft 27, the mover shaft 27 is heat-treated or surface-treated to increase its mechanical strength and move to the bearings 25 and 26. It is possible to improve the wear resistance of the bearing portion that is supported freely.

Next, FIG. 5 is a vertical cross-sectional view of the moving element of the essential part showing another embodiment of the present invention. In FIG. 5, the shaft 37 of the moving element 2 is made of a magnetic material or a non-magnetic material, and has a cylindrical shape between the outer peripheral surface and the inner peripheral surfaces of the pair of ring-shaped moving element cores 28a and 28b. The permanent magnets 38 are arranged so as to fit together, and the permanent magnets 38 are integrally fixed to the mover shaft 37 and the mover iron cores 28a and 28b arranged at a predetermined interval in the axial direction. Has been done.

The predetermined distance between the mover iron cores 28a and 28b means the mover iron core 28a as shown in FIG.
And the movable element small tooth 30 disposed on the movable element iron core 28b has a tooth pitch of 1 in the axial direction.
It is set to deviate by 1/2.

The permanent magnet 38 is composed of the moving element core 28.
The outer peripheral surface of one part of the permanent magnet 38 fitted to the inner peripheral surface of a is the N pole, and the outer peripheral surface of the other part of the permanent magnet 38 fitted to the inner peripheral surface of the mover iron core 28b. The outer peripheral surface is magnetized in a direction perpendicular to the mover shaft 37 so as to have an S pole. Therefore, the moving element small tooth 30 of the moving element core 28a is an N pole, and the moving element tooth 30 of the moving element core 28b is S.
It is magnetized to the pole.

In the mover 2 as described above, since the main magnetic flux from the permanent magnet 38 is generated in the direction perpendicular to the mover shaft 37, its magnetic path is the N pole of the permanent magnet 38.
Moving iron core 28a, stator iron core 10, moving iron core 28
b, since it is formed according to the normal path that passes through the S pole of the permanent magnet 38 and does not pass through the mover shaft 37, the mover shaft 37
Is not axially magnetized. As a result, the leakage magnetic flux to the shaft end can be suppressed to be small.

As for the permanent magnet 38, when a radial anisotropic permanent magnet 38 is used, the mover shaft 3
7 is made of a magnetic material, and when the isotropic permanent magnet 38 is used, the mover shaft 37 can be made of a non-magnetic material.

Note that the technique of the present invention is not limited to the technique in the above-described embodiment, and may be implemented by means of another mode that achieves the same function. Can be changed or added.

[0026]

As is apparent from the above description, according to the present invention, a stator having a plurality of salient poles radially arranged toward the inside, and axially movable in the stator. And a permanent magnet for magnetizing the pair of moving element cores into N and S poles, respectively. In the linear pulse motor comprising, the pair of mover iron cores are formed in a ring shape, the axis of the mover is made of a magnetic material or a non-magnetic material,
The permanent magnet is formed in a cylindrical shape, is disposed between the pair of moving element cores and the moving element shaft, and is fitted to the inner peripheral surfaces of the moving element cores. Since the outer peripheral surface of one part is the N pole and the outer peripheral surface of the other part is the S pole, the direction of the magnetic flux from the permanent magnet is not the same as the axial direction of the mover. , Is perpendicular to the axis of the mover. Therefore, a magnetic steel-based material or a non-magnetic material can be used for the mover shaft, and the magnetic flux leaking to the shaft end can be suppressed.

Therefore, when the mover shaft is made of a steel material, it can be heat-treated to enhance its mechanical strength and improve the wear resistance of the bearing portion.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a linear pulse motor of the present invention.

FIG. 2 is a diagram showing a magnetic flux distribution of FIG.

FIG. 3 is a plan view of a stator iron plate forming a stator core.

FIG. 4 is a development view of a stator small tooth portion formed when the stator iron plates of FIG. 3 are rotationally laminated at a predetermined angle, as viewed from the side of a mover.

FIG. 5 is a vertical cross-sectional view of a moving element of the essential part showing another embodiment of the present invention.

FIG. 6 is a vertical sectional view of a conventional linear pulse motor.

7 is a diagram showing the magnetic flux distribution of FIG.

[Explanation of symbols]

 1 stator 2 mover 10 stator iron core 11, 12, ... 20 salient pole 21 stator small teeth 27, 37 shafts 28a, 28b mover iron core 30 mover small teeth 31a, 31b, 38 permanent magnet 32,33 ring-shaped member

Claims (2)

[Claims] 1. A stator core having a plurality of salient poles radially arranged inward and axially formed with a plurality of stator small teeth on an inner peripheral surface of the salient pole. And a stator having the stator, which is movably supported in the axial direction in the stator, and a plurality of stator small teeth are formed on the outer peripheral surface facing the stator small teeth at an equal pitch in the axial direction. And a mover having at least a pair of mover iron cores arranged at a predetermined interval in the axial direction and a permanent magnet for magnetizing the pair of mover iron cores to an N pole and an S pole, respectively. In the linear pulse motor, the pair of mover iron cores are formed in a ring shape, the axis of the mover is made of a magnetic material or a non-magnetic material, and the permanent magnet is formed in a cylindrical shape. When it is arranged between the child iron core and the mover shaft, In addition, it is magnetized so that the outer peripheral surface of one part of the permanent magnet fitted to the inner peripheral surface of the mover core becomes the N pole and the outer peripheral surface of the other part becomes the S pole. Characteristic linear pulse motor. 2. The mover shaft is made of a magnetic material, and the cylindrical permanent magnets form a pair, and are separately arranged between each of the pair of mover iron cores and the mover shaft. In addition, one of the outer peripheral surfaces is magnetized so as to have an N pole, the inner peripheral surface has an S pole, and the other outer peripheral surface has an S pole and an inner peripheral surface has an N pole. Linear pulse motor described in.