JPH0236742A - Step motor and manufacture thereof - Google Patents

Abstract

PURPOSE:To eliminate the coil frame by forming the section of a stator body for winding a coil through sintering of fine magnetic powder applied with insulation coating. CONSTITUTION:A pair of disc magnets 12 are held while being separated in the axial direction of a rotary shaft 11. A cylindrical yoke 22 made of magnetic material and a pair of yokes 24 are combined to form a stator 20. In the yoke 22, flanges 22b are formed at the opposite ends of a cylindrical main pole 22a and a flange 22c is provided in the center of the main pole 22. Many magnetic poles 23 are formed in the circumferential direction on the surface of the flange 22b. Coils are wound between the flanges 22b and the central flange 22c. The yoke 22 is formed by applying insulation coating on pure iron and producing needle type or spherical microcapsules of several to 100mu R then molding the microcapsules and sintering.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a step motor.

[Prior Art] This type of step motor includes a rotor equipped with a disc-shaped magnet in which a plurality of magnetic poles are arranged so as to have different polarities alternately in the circumferential direction, and a plurality of magnetic poles facing the disc-shaped magnet. Some are equipped with a stator that is excited by a coil.

The coil is wound around a stator body made of a magnetic material, and a coil frame made of an insulating material is generally provided for insulation between the stator body and the coil.

[Problems to be Solved by the Invention] In the above-mentioned conventional configuration, a coil frame is required to wind the coil around the stator body made of a magnetic material, which increases the number of parts and increases the size of the coil frame. The opening theme is that the number of turns in the coil decreases by the amount of wall thickness, and the torque decreases.

The present invention aims to solve the above-mentioned problem, and by selecting the material of the stator body, an insulating layer is formed in the part of the stator body where the coil is wound, thereby making it possible to form a coil. The object of the present invention is to provide a step motor that does not require a frame and a method for manufacturing an fJ step motor that is suitable for this configuration.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention includes a stator body in which at least a portion of the stator body around which the coils are wound is formed by sintering fine magnetic powder coated with an insulating coating. There is.

In addition, a first yoke having magnetic poles facing one side of the disc-shaped magnet is formed by molding and sintering fine magnetic powder coated with an insulating coating, and after winding a coil around the 17th yoke, It is desirable to manufacture the stator body by magnetically coupling the second yoke 1, 7 with the first yoke to form the stator body, the second yoke having a magnetic pole facing the other surface of the disc-shaped magnet.

[Function] According to the above configuration, for the part (a) 7 where the coil is wrapped around the stator body, the magnetic material (7) w with an insulating coating is sintered with powder (■2). Since the structure is 12, an insulating layer is formed on the surface of the stator body, and there is no need to install a coil frame, leading to a reduction in the number of parts and an increase in the number of turns of the coil.

Further, according to the above manufacturing method, the insulating layer can be formed only at important points, and the insulating layer can be formed thinly, so that the magnetic efficiency is hardly affected.

[Example] In this example, a step motor of a type equipped with a pair of disc-shaped magnets as shown in Fig. 1 is exemplified.
': The present invention is not limited to this, but the technical concept of the present invention can be applied as long as the coil is wound around a member made of a magnetic material.

As shown in FIG. 1, a pair of disc-shaped magnets 12 are held apart in the axial direction of the rotating shaft 11, so that the rotor 10
is formed. Each disc-shaped magnet 12 is formed so that a large number of magnetic poles 13 are alternately different in the circumferential direction, and each magnetic pole 13 is magnetized so that the front and back sides are different. Furthermore, the hundred disk-shaped magnets 12 are magnetized at the same pitch, but are arranged so as to be shifted from each other by π/2 in electrical angle. The hundred disk-shaped magnet 12 is fixed to the rotating shaft 11 by a bush 14 held by the rotating shaft 11.

The rotating shaft 11 is rotatably held relative to the stator 20. The stator 20 is formed by combining a cylindrical first yoke 22 and a pair of second yokes 24 made of a magnetic material. The first yoke 22 is formed in such a shape that flanges 22b are formed at both ends of a cylindrical main column 22a, and a flange 22c is provided at the center of the main column 22a.

The rotating shaft 11 of the rotor 10 is inserted through the main column 22a, and bearings are provided at both ends of the main column 22a.

On the surface of the flange 22b provided at both ends of the main pillar 22a,
A large number of magnetic poles 23 are formed at the same number on the circumference. That is, the surface of the flange 22b is formed in a shape in which concavities and convexities are continuous in the circumferential direction, and the convex portions act as magnetic ai23. In the first yoke 22, a coil 21 is wound between each of the flanges 22b and the center flange 22c, as shown in FIG.

The first yoke 22 is formed by applying an insulating coating such as epoxy to pure iron, molding it into fine powder into needle-shaped or spherical micro-cubes of several pi to 1.00 LI, and then sintering it. Since an insulating layer is formed on the surface of the coil 21, the coil 21 can be wound without providing an insulating coil frame. by the way.

Each second yoke 24 is formed in a cylindrical shape, and on one bottom surface, a large number of magnetic poles 25 facing the magnetic poles 23 of the first yoke 22 are arranged in a row in the circumferential direction.

The magnetic pole 25 is formed by punching or stamping. Further, the other bottom surface of the second yoke 24 is in contact with the center flange 22c of the first yoke 22, so that the second yoke 24
The first yoke 22 and the second yoke 2 are magnetically coupled to each other.
4 forms the stator body. That is, coil 2
1, the magnetic pole 23 of the first yoke 22 and the corresponding magnetic pole 25 of the second yoke 24 are excited to have different polarities. Between the magnetic pole 23 of the first yoke 22 and the magnetic pole 25 of each second yoke 24, a disc-shaped magnet 12 is provided.
As shown in FIG. 3, a step motor is formed in which the second yoke 24 also serves as a housing.

With the above configuration, the rotor 10 can be rotated by passing pulse currents whose phases are shifted by π/2 to each coil 21, as shown in FIG. 4. In addition, as described above, since the coil 21 can be directly wound on the first yoke 22 without using a coil frame, the number of turns of the coil 21 can be increased compared to the conventional case with the same external dimensions, and the torque can be increased. This will lead to improvements in performance. Further, since the coil 21 is directly wound around the first yoke 22 which is a magnetic material, there is an advantage that magnetic loss is extremely small and the heat generated from the coil 21 can be easily dissipated. Furthermore, the first yoke 2 around which the coil 21 is wound
Since only 2 is made of a magnetic sintered body coated with an insulating coating and the insulating layer can be formed thinly, magnetic loss due to the presence of the insulating layer can be kept to a minimum.

By the way, as shown in FIG. 5, the first yoke 22 can be formed by combining a pair of yoke bodies 26. Each yoke body 26 is formed by drawing a sheet metal, and has a cylindrical shape with a flange 26a on one bottom surface. Also; there is a second
A magnetic pole 23 facing the magnetic pole 25 of the yoke 24 is formed by punching or the like. Inside each yoke body 26, a sixth
As shown in the figure, a bearing 27 is provided to rotatably hold the rotating shaft 11 of the rotor 10. In addition, each yoke element body 2
A coil 21 made of so-called cement wire is attached to the outer periphery of the coil 6 .

According to the above configuration, since the first yoke 22 can be created by sheet metal processing, manufacturing becomes easy and material costs can be reduced.

As another configuration of the stator body, as shown in FIG.
The first yoke 22 is formed by a yoke shaft 28 and a flange plate 29, and the second yoke 24 is formed by a yoke tube 3p and a flange plate 3.
1 may be formed.

That is, the first yoke 22 has a yoke shaft 28 having a flange 28b at the center of the main shaft 28a.
A bearing 27 is attached to a. A magnetic pole 23 is formed on the flange plate 29 by punching such as etching, and is connected to both ends of the main shaft 28a by adhesion or welding. The first yoke 22 thus formed
between the flange 28b and each flange plate 29.
As shown in the figure, a coil 21 is wound. Here, important parts of the first yoke 22 are coated with an insulating coating, and the coil 21 is directly wound without a coil frame.

On the other hand, the second yoke 24 is formed by attaching a flange plate 31 to one bottom surface of a cylindrical yoke tube 30, and a magnetic pole 25 is formed on the flange plate 31 by punching such as etching. The flange plate 31 is coupled to the yoke cylinder 30 by adhesive or welding. As shown in FIG. 9, the second yoke 24 formed in this way has the opposite bottom surface of the flange plate 31 and the flange 2 of the first yoke 22.
It is coupled to the first yoke 22 in such a way that it comes into contact with the first yoke 8b.

By the way, the flange plates 29 of the first yoke 22 and the second yoke 24. Since the flange plates 31 have the same shape, when they are formed by punching, they can be formed with one die. In addition, when producing small quantities of items with different numbers of magnetic poles,
This can be done using processing methods such as etching, and
By changing only the flange plates 29 and 31, it is possible to easily accommodate the difference in the number of magnetic poles. In other words, if the product is produced in small quantities, it can be processed at relatively low cost without investing in molds.

[Effects of the Invention] As described above, the present invention is characterized in that at least the portion of the stator body around which the coils are wound is formed by sintering fine magnetic powder coated with an insulating coating. The part where the coil is wound is formed by sintering fine magnetic powder coated with an insulating coating, so an insulating layer is formed on the surface of the stator body, so it is not necessary to provide a coil frame. This has the advantage of reducing the number of parts and increasing the number of coil turns.

In addition, a first yoke having magnetic poles facing one side of the disc-shaped magnet is formed by molding and sintering fine magnetic powder coated with an insulating coating, and after winding a coil around the first yoke, If the stator body is manufactured by magnetically coupling a second yoke with a magnetic pole facing the other surface of the disc-shaped magnet to the first yoke, the insulating layer can be formed only at key points. Moreover, since the insulating layer can be formed thinly, magnetic efficiency is hardly affected, and an efficient step motor can be provided.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of an embodiment of the present invention with the coil removed; Fig. 2 is an exploded perspective view of the same; Fig. 3 is an external perspective view of the same; Fig. 4 is a current waveform flowing through the coil; FIG. 5 is an exploded perspective view showing another step motor, FIG. 6 is a sectional view of the same as above, FIG. 7 is an exploded perspective view of another step motor, and FIG. 8 is an exploded perspective view of another step motor. The first yoke used is wrapped with a coil! FIG. 9 is an external perspective view of the same. DESCRIPTION OF SYMBOLS 10... Rotor, 11... Rotating shaft, 12... Disk-shaped magnet, 13... Magnetic pole, 20... Stator, 21...
... Coil, 22 ... First yoke, 23 ... Magnetic pole,
24...Second yoke, 25...Magnetic pole. Agent Patent Attorney Ishi 1) Chief 7 Figure 2 Figure 5 Figure 3 Figure 4 Figure π Figure 6 Figure 7 Figure 8 Figure 9

Claims (2)

[Claims] (1) A rotor that has a rotating shaft equipped with a disc-shaped magnet in which a plurality of magnetic poles are arranged so that the poles are alternately different in the circumferential direction, and a stator body that has a plurality of magnetic poles that oppose the disc-shaped magnet. In a step motor equipped with a stator equipped with a coil that excites each magnetic pole so that the rotor rotates in stages, at least the portion of the stator body where the coils are wound is made of magnetic fine powder coated with an insulating coating. A step motor comprising a sintered body of. (2) A rotor that has a rotating shaft with a disc-shaped magnet in which a plurality of magnetic poles are arranged so that the poles are alternately different in the circumferential direction, and a stator body that has a plurality of magnetic poles facing the disc-shaped magnet. In a method for manufacturing a step motor, the step motor is equipped with a stator equipped with a coil that excites each magnetic pole so that the rotor rotates in stages, and the method includes molding fine powder of a magnetic material coated with an insulating coating and then sintering the motor. A first yoke having magnetic poles facing each other is formed on one surface of the disc-shaped magnet, and the first
A step characterized in that, after winding a coil around the yoke, a second yoke having a magnetic pole facing the other surface of the disc-shaped magnet is magnetically coupled to the first yoke to form a stator body. How to manufacture a motor.