JPH05103456A - Pulse motor - Google Patents

Abstract

PURPOSE:To get a small-sized and high-output pulse motor. CONSTITUTION:Salient poles 20a are made at specified intervals in circumferential direction at a stator part 20, and an exciting coil 20b is wound on each salient pole 20a. And, a first permanent magnet 24 is incorporated into each salient pole 20a. Second permanent magnets 27 are incorporated at specified intervals (the intervals of formed salient poles) into a rotor part 21, and the first and second permanent magnets 24 and 27 are magnetized axially, respectively, and besides, the directions of magnetization are reverse to each other. By constituting it this way, it becomes the same as that where, substantially two pieces of permanent magnets are arranged in series inside the iron core, and it becomes small, and produces high output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse motor incorporating a permanent magnet.

[0002]

2. Description of the Related Art Generally, this type of pulse motor is a hybrid type pulse motor (hereinafter simply referred to as HB type motor).
This HB type motor has a rotor portion and a stator portion. The HB type motor includes a motor having a permanent magnet on the rotor side (hereinafter referred to as a first HB motor) and a motor having a permanent magnet on the stator side (hereinafter referred to as a second HB motor).
Motor), and generally, the first and second HB motors have the structures shown in FIGS. 2 and 3, respectively. First, the structure of the first HB type motor will be outlined with reference to FIG. The shaft 12 has a rotor 12
Is attached, and a stator 13 is arranged outside the rotor 12 with the shaft 11 as a central axis. The stator 13 is supported by the motor frame 14, and the shaft 11 is rotatably supported by the motor frame 14.

A plurality of salient poles 13a protruding inward in the radial direction are formed on the stator 13 at predetermined intervals in the circumferential direction. The salient poles 13a each have an exciting coil 13a.
b is wound. Further, stator small pole teeth are formed at the tips of the salient poles 13a. On the other hand, the permanent magnet 15 is magnetized inside the rotor 12 and is magnetized in the direction of the shaft 11, and rotor small pole teeth are formed on the outer peripheral surface of the rotor 12.

Next, referring to FIG. 3, in the second HB type motor, the rotor 12 is arranged outside the stator 13 around a predetermined axis, and the stator 13 projects radially outward. Salient poles 13a are formed, and exciting coils 13b are wound around these salient poles, respectively. Permanent magnets 15 are sandwiched between the stator 13 and salient poles 13a, and these permanent magnets 15 are magnetized in a predetermined axial direction. A stator small pole tooth and a rotor small pole tooth are formed on the tip portion of the salient pole 13a and the inner peripheral surface of the rotor 12, respectively.

In both the first and second HB type motors described above, a rotational torque is applied to the rotor by the interaction between the magnetic flux of the permanent magnet and the magnetic flux of the exciting coil. The density is set near the saturation magnetic flux density of the iron core to increase the motor output density (output per unit volume).

[0006]

By the way, the above-mentioned HB
In order to increase the output density of the H-shaped motor, it is necessary to set the magnetic flux density of the permanent magnet as high as possible. However, in order to set the magnetic flux density of the permanent magnet high, both the first and second HB motors are permanently set. It is necessary to increase the size of the magnet itself (that is, increase the volume of the permanent magnet and the cross-sectional area of the magnetic flux generation surface). However, when the permanent magnet is made large, especially when the magnet thickness is increased to obtain a magnetomotive force,
There is a problem that the motor itself becomes longer in the axial direction and the motor becomes larger.

Further, in the first HB type motor, if the rotor shape is the shape shown in the figure, the laminated iron core cannot be used for the rotor, and as a result, iron loss increases, and a permanent magnet is incorporated in such a rotor. In that case, there is a further problem that the iron loss increases.

Further, in the second HB type motor, if an attempt is made to increase the thickness of the permanent magnet while keeping the axial length of the rotor constant, the effective iron core length (the length where the rotor and the stator face each other) is increased. When the effective iron core length is shortened, there is a problem that the output is reduced even if the thickness of the permanent magnet is increased. It is an object of the present invention to provide a pulse motor which is small in size and capable of obtaining a high output.

[0009]

According to the present invention, there is provided an annular rotor portion and an annular stator portion which are arranged around a predetermined axis, and the stator portion has salient poles at predetermined intervals in the circumferential direction. And an exciting coil is wound around each salient pole, and a first permanent magnet is incorporated in each salient pole,
Second permanent magnets are incorporated at the predetermined intervals in the rotor portion, and the first and second permanent magnets are magnetized in the axial direction and the magnetization directions are opposite to each other. A pulse motor is obtained.

[0010]

In the present invention, the first permanent magnet is incorporated in the stator portion at the salient pole position, and the second permanent magnet is incorporated in the rotor portion at the same spacing as the salient pole spacing. Since the permanent magnets are magnetized in the axial direction and the magnetization directions are opposite to each other, it is as if the first and second permanent magnets, that is, the two permanent magnets are arranged in series. As a result,
The magnetomotive force generated by the magnet can be increased without increasing the axial length. Therefore, the magnet operating point can be set high, and the amount of magnetic flux in the motor can be increased.

[0011]

EXAMPLES The present invention will be described below with reference to examples. Referring to FIG. 1, the illustrated pulse motor includes an annular stator 20 and an annular rotor 21.
1 is arranged outside the stator 20 around a predetermined axis. A plurality of salient poles 20a (a total of twelve salient poles in FIG. 1) protruding outward in the radial direction are formed on the stator 20 at predetermined intervals in the circumferential direction.
An exciting coil 20b is wound around. Every other exciting coil 20b is connected in series and every salient pole 20
Small teeth with a pitch P are formed at the tip of a. Similarly, small teeth having a pitch P are formed on the inner peripheral surface of the rotor 21.

As shown in FIG. 1B, the stator 20 is divided into two in the radial direction, and the divided stators 22 and 23.
A plurality of permanent magnets (first permanent magnets) 24 are arranged between them at predetermined intervals along the circumferential direction (only one permanent magnet 24 is shown in FIG. 1). Specifically, the permanent magnet 24 is arranged at the position of each salient pole 20a. Similarly, the rotor 21 is also divided into two in the radial direction, and the permanent magnets 27 are arranged between the divided rotors 25 and 26 at intervals such that the salient poles 20a are formed along the circumferential direction ( Only one permanent magnet 27 is shown in FIG. 1). These permanent magnets 24 and 27 have the same axial length, and
As shown in (b), each is magnetized in the axial direction. Furthermore, the magnetizing directions of the permanent magnets 24 and 27 are opposite to each other. That is, the permanent magnet 24 has the N pole-S.
If the pole is magnetized, the permanent magnet 27 will be magnetized to the S pole-N pole.

In the pulse motor constructed as described above, when a current is passed through the exciting coil 20b, magnetic flux is generated between the stator 20 and the rotor 21 as shown by the broken line in FIG. 1 (b). On the other hand, a magnetic flux from the N pole to the S pole is generated between the permanent magnets 24 and 25 in the direction indicated by the solid arrow. That is, the magnetic flux generated inside the iron core increases. As described above, the stator 20 and the rotor 2
By arranging the permanent magnets 24 and 27 in 1 respectively, substantially the same effect as arranging two permanent magnets in series in the iron core can be obtained, and without increasing the size of the motor itself, The magnetic flux can be increased.

[0014]

As described above, in the present invention, the first permanent magnet is incorporated in the stator portion at the salient pole position, and the rotor portion is provided with the second permanent magnet at the same spacing as the salient pole spacing. As a result, the first and second permanent magnets are magnetized in the axial direction and the magnetization directions are opposite to each other. This is the same as arranging two permanent magnets in series in the iron core, and as a result, the amount of magnetic flux can be increased without increasing the axial length. That is, there is an effect that a small size and high output can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a pulse motor according to the present invention.

FIG. 2 is a diagram showing an example of a conventional pulse motor.

FIG. 3 is a diagram showing another example of a conventional pulse motor.

[Explanation of symbols]

 11 shaft 12 rotor 13 stator 14 motor frame 20 stator 21 rotor 20a salient pole 20b exciting coil 22,23 split stator 24 permanent magnet 25,26 split rotor 27 permanent magnet

Claims (1)

[Claims] 1. An annular rotor portion and an annular stator portion arranged centering on a predetermined axis are provided, and salient poles are formed at predetermined intervals in the circumferential direction on the stator portion, and the salient poles are respectively excited. A coil is wound, a first permanent magnet is incorporated in the salient pole, and a second permanent magnet is incorporated in the rotor portion at the predetermined interval. The permanent magnets are magnetized in the axial direction, and the magnetizing directions are opposite to each other.