JPS62185551A - Composite stepper motor - Google Patents

Abstract

PURPOSE:To increase the efficiency and the torque of a motor by forming a cutout on a pole to reduce a sectional area. CONSTITUTION:A composite stepper motor 20 has a rotor having a magnet 24 secured to a rotational shaft 21 and rotor cores 25, 26. Suitable number of teeth 27, 28 are formed on the outer peripheral surfaces of the cores 25, 26, while the teeth 27, 28 are displaced by 1/2 pitch in different polarities. A stator core 30 is so arranged as to surround the rotor, and stator coils 39 are wound on the poles 31-38. Suitable number of teeth 40 are formed on the inner peripheral surface of the core 30. In this case, cutouts 41 formed along the circumference with the shaft 21 as a center are formed on the position opposed to the magnet 24 of the rotor on the poles 31-38. Thus, the formation of a magnetic path passing the sole poles 31-38 is limited to reduce the magnetic path which does not contribute to the torque of the motor.

Description

Detailed Description of the Invention Industrial Application This invention has a large number of teeth cut on the outer periphery of the rotor and the inner periphery of the stator, and the rotor has magnets magnetized in the axial direction. This relates to a built-in compound stepping motor.

A conventional compound stepping motor 1 is shown in Figs. 4 and 5.
It is shown in the figure. In the figure, reference numeral 2 denotes a rotating shaft, which is rotatably supported by frames 4, 4 via bearings 3, 3, and a magnet 5 is fitted approximately at the center of this rotating shaft 2. Further, rotor cores 6a and 6b are fitted onto the rotating shaft 2 with the magnet 5 sandwiched therebetween.

An appropriate number of teeth 7a are provided on the outer peripheral surfaces of the rotor cores 6a, 6b.

7a... and teeth 7b, 7b... are formed, and the teeth 7a, 7a... formed on the rotor core 6a and the teeth 7b, 7b... formed on the rotor core 6b are approximately 1/ In addition to being shifted by 2 pitches, the rotor core 6a and the rotor core 6b have different polarities due to the magnet 5.

On the other hand, the magnet 5 and the rotor core 6a.

A stator core 8 is disposed to surround the rotor 6b, and stator coils 9, 9, . . . are wound around poles 81 to 88 of the stator core 8 in the axial direction of the rotating shaft 2. The number of poles is 8, and each pole is shown as 81 to 88 as shown in FIG. In addition, stator core 8
The rotor core 6a is disposed on the inner peripheral surface of the rotor core 6a.

Teeth 7a, 7a... or teeth 7 formed on the outer peripheral surface of 6b
b.

An appropriate number of teeth 1.0.10 that can appropriately face 7b...
... is formed. This stator core 8 is manufactured by laminating pressed iron plates to a predetermined thickness or by processing sintered metal. Note that the stator core 8 and stator coil 9 constitute a stator.

Then, when the excitation position of the stator is sequentially rotated, the effects of the magnetic field from the stator coil 9 and the magnetic field from the magnet 5 cause the teeth 10° 10... of the stator core 8 and the teeth 7a, 7a... or the rotor core 6a to rotor core 6b
The teeth 7b, 7b, . . . attract each other, causing the rotor to rotate by a predetermined angle.

For optical use J~Let's solve Since they have the same shape, the following problems arose.

Now, the rotor core 6a is set to the north pole by the magnet 5.
It is assumed that the rotor core 6b has S-pole magnetism, and in the case of -phase excitation, the poles 81 and 85 have S-pole magnetism and the poles 83 and 87 have N-pole magnetism depending on the excitation state. In this state, the magnetic path for contributing to the torque of the motor must extend from the rotor core 6a through the pole 81, the stator core 8, and the pole 85 to the rotor core 6b. However, as described above, since the cross-sectional shape of the stator is the same at any position, a magnetic path from the rotor core 6a through the pole 81 and directly to the rotor core 6b is easily constructed. In this way, the magnetic path from a single pole to the rotor is a magnetic path with magnetic leakage and does not contribute to torque. The existence of a magnetic path that does not contribute to torque causes a decrease in motor efficiency and causes a decrease in torque.

Purpose In view of the above-mentioned problems, it is an object of the present invention to provide a composite stepping motor with improved efficiency by preventing as much as possible the occurrence of magnetic paths that would cause magnetic leakage.

In order to achieve the above-mentioned object, a compound stepping motor according to the present invention has a magnet fitted to the rotating shaft, and a rotor core that is sandwiched between the magnets. is fitted onto a rotating shaft to form a rotor, and a stator having an appropriate number of poles and a stator coil wound around the poles is arranged so as to surround the rotor. A cutout portion is formed by cutting out a portion of the pole facing the magnet along a circumference centered on the rotation axis.

Effect: Due to the presence of the cutout, the cross-sectional area of the pole is reduced, and the configuration of the magnetic path from the rotor core directly to the rotor core via a single pole is restricted.

EXAMPLE Hereinafter, a composite type steering motor 20 according to the present invention will be specifically explained based on the preferred embodiment shown in FIGS. 1 to 3.

In the figure, reference numeral 21 denotes a rotating shaft, which is supported by a frame 23.23 via a bearing 22.22, and a magnet 24 is fitted approximately in the center of this rotating shaft 21. Moreover, the rotor cores 25 and 26 are connected to the rotating shaft 21 with this magnet 24 in between.
is attached to. The outer peripheral surface of the rotor core 25, 26 has an appropriate number of teeth 27, 27... and teeth 28, 28...
・ is formed, and teeth 2 formed on the rotor core 25
7°27... and teeth 28 formed on the rotor core 26.
The rotor core 25 and the rotor core 26 have different polarities due to the magnet 24.

On the other hand, the magnet 24 and the rotor core 25°26
A stator core 30 is disposed so as to surround a rotor consisting of a rotor, and stator coils 39, 39, . In this embodiment, the number of poles is eight, and each pole is shown as 31 to 38 as shown in FIG.

Further, on the inner circumferential surface of the stator core 30, an appropriate number of teeth 40. which can appropriately oppose the teeth 27, 27, . . . or teeth 28, 28, . 40... are formed. This stator core 30 is manufactured by laminating pressed iron plates to a predetermined thickness. In each of the poles 31 to 38 described in "2," cutout parts 4+, 41, etc. are formed by cutting out the parts facing the magnets 24 of the rotor along the circumference around the rotation axis 21. has been done. That is, as shown in FIGS. 2 and 3, the stator core 30 includes stator yokes 43, 43, . This stator yoke 43.4 is formed to protrude.
The tips of 3... are widened along the circumference around the rotating shaft 21 to form each pole 31-38, and each pole 31-38 is further cut out approximately in the center to form a notch. 41.41... are formed. Sandwiching these notches 41, 41..., each pole 31-38 is
Pole upper parts 31a to 38a and pole lower parts 31b to 38b
It is divided into.

The operation of the embodiment of the composite stepping motor 20 according to the present invention constructed as described above will be described below.

Now, the magnet 24 makes the rotor core 25 magnetically N-pole and the rotor core 26 magnetically S-pole, and in the case of -phase excitation, depending on the state of excitation, the poles 31 and 35 become S-pole.
Assume that poles 33 and 37 are N poles. In this state, when looking at the rotor core 25, the tip surfaces of the teeth 27, 27... of the rotor core 25 are aligned with the poles 31.
．． The teeth 40°4 of the poles 32, 34, 36, 38 are opposed to the tip surfaces of the teeth 40.
They face the tip surfaces of the poles 33, 37 with a shift of approximately 1/2 pitch, and do not face the teeth 40, 40, etc. of the poles 33, 37 at all. In this state, the magnetic path that contributes to the torque of the motor consists of a path from the rotor core 25 to the rotor core 26 through the upper pole 31a of the stator core 30, the stator yoke 43, the peripheral wall 42, and the lower pole 35b. Ru. Also, from the rotor core 25, the pole upper part 31
a, magnetic path leading to rotor core 26 via stator yoke 43 and lower pole 31b (magnetic path that does not contribute to torque)
However, the pole 31 has a notch 41 approximately at its center.
is formed and the cross-sectional area of the pole 31 is reduced, so the magnetic resistance between the upper pole 31a and the lower pole 31b increases, and the magnetic flux in the magnetic path passing through the upper pole 31a and the lower pole 31b decreases. . Therefore, a magnetic path with magnetic leakage that does not contribute to torque is unlikely to be formed.

Then, when the next excitation state is such that the pole 32.36 becomes the S pole and the pole 34.38 becomes the N pole, the rotor core 25 is attracted to the pole 32.36 because it is the N pole, and the teeth 27.27 of the rotor core 25 are attracted to the pole 32.36. The tip surfaces of the poles 32, 36, 40, 40, .
Opposed to the tip surface of 40... with a shift of approximately 1/2 pitch,
The teeth 40, 40, etc. of the poles 34, 38 no longer face each other at all. By sequentially changing the excitation state in this way, the rotor rotates.

In addition, in this embodiment, the poles 31 to 38 have notches 41.
, 41 . . . are shown as they are formed, but a filling member made of a non-magnetic material such as synthetic resin may be embedded in the notches 41 , 41 . When the filling member is embedded -8=, the poles 31 to 38 are reinforced and the strength is improved.

Effects As explained above, in the compound stepping motor according to the present invention, a magnet is fitted to the rotating shaft, and a rotor core is also fitted to the rotating shaft with the magnet sandwiched between them to form a rotor, and an appropriate number of poles are fitted. In a compound stepping motor having a stator coil wound around the pole and a stator arranged so as to surround the rotor, the part of the pole facing the magnet is centered around the rotation axis. Since the structure is such that the notch is formed by cutting out along the circumference, the following effects can be obtained.

Since the above-mentioned notch is formed in the pole and the cross-sectional area is reduced, the configuration of the magnetic path passing through a single pole is restricted, and therefore the configuration of the magnetic path that does not contribute to the motor torque is minimized. Therefore, it is possible to increase motor efficiency and torque.Moreover, since it has a simple structure of forming a notch, it can be provided at low cost and has high practicality. have an effect.

[Brief explanation of drawings]

1 to 3 show preferred embodiments of the compound stepping motor according to the present invention, in which FIG. 1 is taken in the axial direction of the rotating shaft and cut along line I-1 in FIG. 2. Figure 2 is a cross-sectional view of the stator taken along the line ■-■ in Figure 1, and Figure 3 is a cross-sectional view of the stator taken along the same <m-m line. . Figures 4 and 5 show conventional compound stepping motors, with Figure 4 being a sectional view corresponding to Figure 1, and Figure 5
The figure is a cross-sectional view corresponding to FIG. 3 taken along the line -V in the upper part of FIG. 4. 21... Rotating shaft 24... Magnet 25
．． 26... Rotor core 30... Stator core 3
1 to 38...Pole 39...Stator coil 41...Notch part 1st figure side 21--One time base 1m 24--
--Nuinenet 25.26--Rotor core
3O---VXX cheek core 3---Stay F3
1 Ij 41 ---- t71 Bunshiro p Figure 2 Figure 3 Figure 4 Figure 5! 0

Claims (1)

[Claims] A magnet is fitted to the rotating shaft, and a rotor core is also fitted to the rotating shaft with the magnet sandwiched between them to form a rotor, which has an appropriate number of poles, and a stator coil is wound around the poles. In a compound stepping motor in which a rotated stator is arranged so as to surround the rotor, the part of the pole facing the magnet is cut out along the circumference around the rotation axis to form a notch. A compound stepping motor characterized by forming: