JPS62118752A - Stepping motor - Google Patents

Abstract

PURPOSE:To decrease the diameter of a motor sharply by forming a magnetic closed loop where a yoke is provided surrounding a pair of stator coils arranged along the rotating shaft on the both axial ends of a rotor magnet fixed to a rotating shaft. CONSTITUTION:A rotor magnet 24 is fixed to a rotating shaft 26 through a rotor yoke 25. ON the axial extension of a magnet 24 stator coils 20 and 23 are provided, which are surrounded by the first stator yoke 18 & the second stator yoke 19 and by the first stator yoke 21 & the second stator yoke 22 respectively. A closed magnetic circuit is formed at the stator yokes 18 & 19 and 21 & 22 respectively depending on whether the coils 20 and 23 are electrically conducted and depending on the direction of electric charge so that the magnetic efficiency is developed. Thus, the diameter of the motor can be sharply decreased, which is suitable for slimming the equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a stepping motor using a magnet as a rotor.

2. Description of the Related Art In recent years, stepping motors have been widely used in information-related equipment and office automation equipment as actuators suitable for digital microcomputer control.

An example of the conventional stepping motor mentioned above will be described below with reference to the drawings.

Fig. 2 shows a cross-sectional view of a conventional stepping motor.◎In Fig. 2, 1 and 6 are stator yokes A that have claw-pole teeth in the portions facing the rotor magnets. 2 and 7 are stator yokes B similar to stator yokes 1 and 6. ◇Here, the stator yokes 1 and 2 and 6 and 7 have teeth phases of 18 in electrical angle.
In addition, stator yokes 1 and 6 and stator yokes 2 and 7 each differ by 900 degrees in electrical angle. Reference numeral 5 denotes a partition plate for interrupting magnetic connection between the stator yokes 2 and 6, and stator yokes 2 and 7 of the stator yokes B are integrally fixed to the partition plate 6. 3 and 8 are coil bobbins, 4 and 9 are stator coils, and these two coils constitute a two-way stepping motor.

10 is a rotor magnet, 11 is a spacer, 12 is a shaft, 13 and 14 are stator side plates, and 16 and 16 are metal bearings. Further, 17 is a lead wire for feeding power to the stator coils 4 and 9.

To explain the operation of the stepping motor configured as above, by energizing the stator coils 4 and 9 while changing the energization polarity sequentially, the rotor magnet 10 is -ri 2 and 7
Since the phases differ by 90' electrical angle, each step rotates by 900 electrical angle.

Problems to be Solved by the Invention However, the above configuration has the disadvantage that the motor diameter inevitably increases because the stator coil is disposed on the outer periphery of the magnet.

In view of the above problems, the present invention aims to provide a step motor with a small motor diameter.

Means to Solve the Problems In order to solve the above problems, the stator coils are placed on the side of the rotor magnet along the thrust axis, and a similar configuration was used to create a magnetic closed loop of the stator coils using a stator coater. It is prepared.

Function: With the above configuration, there is no need to arrange the stator coil on the outer periphery of the magnet, and a step motor with a small diameter becomes possible.

EXAMPLE Hereinafter, a stepping motor according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a sketch of the stepping motor of the present invention. In FIG. 1, 18 is a first stator yoke having claw-pole type teeth at the center of the motor, and 19 is a second stator yoke.The phases of the teeth 18 and 19 are electrical angle There is a difference of 1800. Reference numeral 20 denotes a first stator coil in which a first stator yoke 18 and a second stator yoke 19 form a magnetic path. Also, 21 is a first stator yoke, 22 is a second stator yoke, and 23 is a second stator coil.

First stator yoke 21 and second stator yoke 22
As in the case of the stator yokes 18 and 19, the tooth portions of each of the stator yokes have a phase difference of 1800 electrical degrees from each other, and at the same time, the sets of both stator yokes each have a phase difference of 900 electrical degrees.

FIG. 2 shows a cross section of the motor along plane 0PQR in FIG. 1. In the figure, 24 is a rotor magnet, and FIG. 1 shows a case where the rotor magnet 24 has eight poles. Further, 25 is a rotor yoke 26, a shaft, 27 and 28 are coil bobbins, 29 and 30 are bearings 31, and 32 is a thrust spacer.

To explain the operation of this embodiment with reference to FIG. 2, first, when the stator coil 20 is excited, the magnetic flux changes from the first stator yoke 18 to the teeth of the first stator yoke 18 to the rotor magnet to the second magnet. A closed path is formed from the teeth of the stator yoke 19 to the second stator yoke 18 and back to the first stator yoke 18.

Moreover, when the coil 23 is similarly excited, the first stator yoke 21 → the teeth of the first stator yoke 21 → the rotor magnet 24 → the teeth of the second stator yoke 22 → the second stator yoke 22 → A magnetic path for the first stator yoke 21 is formed.

Now, the coil 20 is excited so that the first stator yoke 18 is the north pole and the second stator yoke is the south pole, and the first stator yoke 21 is the north pole and the second stator yoke 22 is the south pole. If we excite it so that it becomes a pole, the result is N
The pole will be centered between the teeth of the first stator yoke 18 and 21, and the south pole will be centered between the teeth 19 and 22 of the second stator yoke.

Next, when the conduction polarity of only the coil 20 is reversed, the polarity of the first stator yoke IEl, 19 is reversed, so that the resulting N pole comes to the center of the teeth of the second stator yokes 19 and 21. , and the south pole is the first stator yoke 18 and 22
It will come to the center of the teeth. Therefore, the composite magnetic pole created by the stator yokes 18 and 19.20°21 is 9 in electrical angle.
This means that it has rotated 0°. Similarly, if the polarity of the coils 23 and 21 is sequentially switched, each time the composite magnetic pole formed by the teeth of the stator yokes 18 to 21 rotates by 90 degrees in electrical angle, and therefore the rotor magnet will rotate accordingly.

Incidentally, in the above explanation, eight poles are used, but it is obvious that the number of poles is not limited to eight poles.

Effects of the Invention As described above, the present invention improves the motor performance by arranging the stator coil laterally along the thrust axis of the rotor magnet and configuring a magnetically closed loop of the stator coil with two types of stator yokes. The diameter can be reduced to a large extent, making it an extremely effective means for making equipment thinner, and its industrial merits are enormous.

[Brief explanation of drawings]

Fig. 1 is a sketch of a stepping motor according to an embodiment of the present invention, Fig. 2 is a sectional view of a conventional stepping motor, and Fig. 3 is a cross-sectional view of a conventional stepping motor.
The figure is a sectional view of a stepping motor according to an embodiment of the present invention. 18...first stator yoke, 19...-
IX 2 stator yoke, 21...first stator yoke, 22...second stator yoke.

Claims (1)

[Claims] A bobbin-wound stator coil, a rotor magnet,
A first stator yoke made by sheet metal processing has claw pole-shaped teeth on the outer periphery of the rotor magnet, and teeth having a phase difference of 180° in electrical angle with the teeth of the first stator yoke. In a stepping motor having a second stator yoke made by sheet metal processing, the stator coil is disposed on the side of the rotor magnet along the thrust axis, and a magnetic closed loop is arranged to surround the stator coil. is composed of the first stator yoke and the second stator yoke to form a yoke pair, and the two yoke pairs are arranged so as to sandwich the magnet from both sides of the magnet in the axial direction, and A stepping motor with a phase difference of 90 degrees in electrical angle between the yoke pair.