JPS6335155A - Motor - Google Patents

Abstract

PURPOSE:To increase the output of a motor without extending its length in the axial direction, by arranging the poles of a stator yoke face to face on both sides of a rotor with one side of a disc type rotor magnetized to N-pole and with the other side to S-pole. CONSTITUTION:A rotor 1 is composed of coaxially connected two pieces of disc type magnets 20 and 22 with one side magnetized to N-pole and the other side to S-pole. On both sides of these disc type magnets 20 and 22 salient poles are provided to divide the circumference in equal part. Opposite to those salient poles, comb-teeth-shaped stator yokes 50, 52, 60 and 62 are provided. Bobbin frames 80 and 82 wound around with stator coils 90 and 92 are put between the outside circumferential sections of stator yokes 50, 52, 60 and 62.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an electric motor, and more specifically, a rotor is provided with salient poles by magnetizing the front and back sides of a disk, and stator magnetic poles are arranged on both sides of the rotor.
The present invention relates to an electric motor that has a flat motor shape, has a large output, and can be driven at a minute step angle.

[Prior Art] In a conventional stepping motor or synchronous motor, as shown in the cross-sectional view of FIG. 6 and the exploded perspective view of FIG. The outer circumferential surface of the cylindrical magnet 36 is divided at equal pitches, and each section is magnetized in the radial direction so that the north pole and the south pole alternate. On the other hand, the stator 38 is made up of a stator core 40 surrounding a donut-shaped coil 39 that is wound around the outer circumferential side of the rotor with a small gap in between.
A comb-shaped stator magnetic pole 46 is arranged opposite to the outer circumferential surface of the magnet 36 of No. 7.

However, the configuration of this conventional stepping motor or synchronous motor has the following problems. Firstly, when a cylindrical magnet material is magnetized with a large number of magnetic poles in the radial direction, the strength of the magnetic poles decreases rapidly as the number of magnetic poles increases, and the output decreases, so the number of magnetic poles is limited.Secondly, the number of magnetic poles is limited. In order to increase the output, it is possible to increase the length of the motor in the axial direction, but this poses problems such as being unsuitable for flat type 81 barrels. In particular, it is not suitable for flat stepping motors that are required to be driven at minute angles and are used in magnetic disk drive devices, the demand of which has been rapidly increasing recently.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned problems of conventional stepping motors or synchronous motors. It is an object of the present invention to provide a stepping motor that can be driven at a minute angle.

[Means for Solving the Problems] The electric motor of the present invention is a rotor in which the centers of two disks are coaxially connected, one side of which is magnetized as an N pole and the other side as an S pole. A rotor whose circumference is equally divided on the outer periphery of both sides of a disk and salient poles are provided radially toward the center of the disk, and two stators wound around the outer periphery of each disk with a slight gap between them. a disc-shaped stator yoke that sandwiches the coil and each of the stator coils from both sides, a comb that faces the salient poles of the disc with a slight gap and equally divides the circumference at the same pitch as the salient poles; The gist is that the stator yoke is provided with a stator yoke provided with tooth-shaped teeth portions.

[Function] The electric motor of the present invention has a configuration in which one surface of the disk-shaped rotor is the N pole and the other surface is the S pole, and the magnetic poles of the stator yoke are arranged opposite to each other on both sides of the rotor. By using a strong magnetic material for the rotor, it is possible to create a stepping motor or synchronous motor with a large output without increasing the length of the motor in the axial direction. Moreover, this makes it possible to meet the demand for flat stepping motors. In addition, since the disk-shaped rotor is axially magnetized, the number of magnetic poles is not so limited as is the case when magnetizing is divided into many parts in the radial direction. The number can be increased, and driving at minute step angles is possible. Since the teeth portions of the stator yoke are arranged in a plane and constitute magnetic poles, the stator yoke can be easily machined with high precision, and even a motor with a minute step angle can be easily manufactured.

[Embodiment] According to an embodiment of the present invention, the pitch of the salient poles is shifted by 1/2 pitch on the front and back of the circular shape, and by 1/4 pitch between the discs, and the pitch of the teeth is shifted by 1/2 on the front and back of the disc. An electric motor is provided in which the pitches are shifted and the discs have the same pitch.According to this embodiment, there is an advantage that the magnetic flux distribution formed by the magnetic poles shows a relatively smooth change, and torque fluctuations are relatively small.

〔Example〕

A preferred embodiment of the present invention will be described below based on the drawings. FIG. 1 is a sectional view of an embodiment in which the present invention is applied to a flat permanent magnet stepping motor. In FIG. 1, the rotor 1 is composed of two disc-shaped magnets 20.22, and the rotor shaft 3 is integrally fixed through the center of the disc-shaped magnets 20.22. Both sides of this rotor shaft 3 are rotatably supported by bearings 40, 42.

The disk-shaped magnets 20 and 22 of the rotor 1 are formed into a disk shape using a magnetic material such as anisotropic ferrite, as shown in the plan view of FIG. 2 (a) and the side view of FIG. 2 (b). The circumference was equally divided on the outer periphery 24 of both sides of each disk 20, 22, and convex stripes were provided radially toward the center of the disk to form salient poles 26. Both outer peripheries 2 of this disc-shaped magnet 20.22
The pitch of the salient poles 26 provided at 4 is 1/1 on the front and back of the disk.
There is a 2 pitch deviation in the circumferential direction, and a 1/4 pitch deviation in the circumferential direction between the disks 20 and 22. In addition, the polarity of the disc-shaped magnets 20 and 22 is 20 m and 22 m on the left side in FIG.
a is the north pole, and right surfaces 20b and 22b are the south poles.

A bobbin frame 80.82 made of an insulating material is arranged surrounding the outer periphery of the disc-shaped magnet 20.22 of the rotor 1 with a slight gap in between, and a stator coil 90.92 is wound around each bobbin frame 80.82. ing.

Stator yoke 50.52.60.62 is shown in Figure 3 (A)
As shown in the overall plan view of , and the partially enlarged plan view of FIG. The inner circumferential portion is a comb-like tooth portion 50b that is provided so as to equally divide the circumference at the same pitch as the salient poles 26 of the disc-shaped magnet and to face the salient poles 26 in the axial direction. Each stator yoke 50.52.60.62 is attached to the inner circumferential side of the motor case 7 with the disk-shaped magnet 20.22 in between, and the teeth portions 50b, 5 of each stator yoke
2b, 60b, 62b are disk-shaped magnets 20.22
It is arranged at a position facing the salient pole 26 in the axial direction with a small gap of about 0.05 m interposed therebetween. In addition, when this stator yoke 50.52°60.62 is installed during assembly, the pitch phase of the teeth portions 50b, 52b, 60b, and 62b is 1/2 pitch on the front and back of the disc, that is, 50b and 52b and 60b and 62b. They are offset in the circumferential direction, and the discs are mutually aligned, namely 50b and 60b and 52b and 6.
In 2b, there is no pitch deviation, stator yokes 52 and 6
A non-magnetic spacer 10 is fitted between the two.

Next, the step movement operation of the stepping motor of this embodiment will be explained based on the developed diagrams of the magnetic poles shown in FIGS. . FIG. 4 (a), (b), (c), and (d) show the protrusion fi26 of the disc-shaped magnet 20.22 of the rotor 1 and the teeth portion 50b of the stator yoke 50.52.60.62.
, 52b, 60b, and 62b. As shown in FIG.
Pulse currents are applied in the order of 92 forward direction→90 reverse direction→92 reverse direction.

When a forward current is applied to the stator coil 90, the teeth 50b of the stator yoke 50 are excited to the S pole and the teeth 52b of the stator yoke 52 are excited to the N pole, as shown in FIG. 4(A). , the N-pole surface 2 of the disc-shaped magnet 20 facing the teeth portion 50b of the stator yoke 50
The salient pole 26 at 0a is attracted to the tooth portion 50b, and the salient pole 26 at the S pole surface 20b is attracted to the tooth portion 52b. On the other hand, since the stealer coil 92 is not energized at all,
The disc-shaped magnet 22 is in a free state, and each salient pole 2
6 is the teeth portion 60b of the stator yoke 60.62, 6
It stops at a position shifted 1/4 pitch to the right from 2b.

Next, when the current in the stator coil 90 is cut off and a forward current is passed through the stator coil 92, the teeth portion 60b of the stator yoke 60 becomes the S pole, and the teeth portion of the stator yoke b2 becomes the S pole, as shown in FIG. 62b is excited to the north pole, so the salient pole 26 on the north pole face 22a of the disc-shaped magnet 22 facing the tooth part 60b of the stator yoke 60 is attracted to the teeth part 60b, and the salient pole 26 on the south pole face 22b is attracted to the tooth part 60b. It is attracted to the teeth portion 62b. As a result, the disc-shaped magnet 2
The 1/4 deviation between the salient poles 26 on both sides of the rotor 2 and the teeth portions 60a, 62a of the stator coils 60, 62 is eliminated, and the rotor 1 moves to the left by 1/4 pitch. On the other hand, since the stator coil 90 is not energized at all, the disc-shaped magnet 20 is in a free state, and each salient pole 26 is connected to the teeth portions 50b, 52b of the stator yoke 50.52.
It will stop at a position shifted 1/4 pitch to the left.

Next, when the current in the stator coil 92 is cut off and a reverse current is passed through the stator coil 90, the teeth portion 50b of the stator yoke 50 becomes N11 as shown in FIG.
Since the teeth portion 52b of the stator yoke 52 is excited to the S pole at i, the teeth portion 50b of the stator yoke 50
The protrusion w126 of the N pole face 20g of the disc-shaped magnet 20 facing
is repelled by the teeth portion 50b, and the salient pole 2 of the S pole surface 20b
6 is repelled by the teeth portion 52b. As a result, the salient poles 26 on both sides of the disc-shaped magnet 20 and the stator coil 50.52
The left side 1/ between the teeth parts 50a and 52a of
The shift of 4 becomes a shift of 17/2 as the rotor 1 further moves to the left by 1/4 pitch. On the other hand, since the stator coil 90 is not energized at all, the disc-shaped magnet 22 is in a free state, and each protrusion i26 is connected to the stator yoke 60.
It stops at a position shifted 1/4 bit to the left from the teeth portions 60b and 62b of 62.

Next, the current in the stator coil 90 is cut off, and the stator coil 90 is cut off.
When a reverse current is passed through the coil 92, the teeth 00b of the stator yoke 6o are excited to the north pole and the teeth 62b of the stator yoke 62 are excited to the south pole, as shown in FIG. 4(d). The salient poles 26 on the Nu surface 22a of the disc-shaped magnet 22 facing the teeth 60b of 60 are repelled by the teeth 60b, and the salient poles 26 on the S pole surface 22b are repelled by the teeth 62b. As a result, the left 1/4 between the protrusion 8i26 on both sides of the disc-shaped magnet 22 and the teeth portions 60a, 62& of the stator coil 60.62
The deviation becomes 1/2 as the rotor 1 further moves to the left by 1/4 pitch. On the other hand, since the stator coil 90 is not energized at all, the disc-shaped magnet 20 is in a free state, and each salient pole 26 is connected to the stator yoke 50, 50.
It stops at a position shifted to the right by 1/4 pitch from the teeth portions 50b and 52b.

Next, when the current in the stator coil 92 is cut off and a forward current is passed through the stator coil 90, the teeth portion 50b of the stator yoke 50 becomes the S pole as shown in FIG. 52b is excited to the north pole, the salient pole 26 on the north pole face 20a of the disc-shaped magnet 20 facing the teeth 50b of the stator yoke 50 is attracted to the teeth 5ob, and the salient pole 26 on the s8i face 20b is attracted to the teeth 5ob. It is attracted to the portion 52b. As a result, the 1/4 deviation on the right side between the salient poles 26 on both sides of the disc-shaped magnet 20 and the teeth portions 50a, 52a of the stator coil 50.52 is reduced by the rotor 1 moving 1/4 pitch to the left. disappears. On the other hand, since the stator coil 92 is not energized at all, the disc-shaped magnet 22 is in a free state, and each salient pole 26 is shifted to the right by 1/4 pitch from the teeth portions 60b and 62b of the stator yoke 60.62. Stops in position.

By repeating the above rotational movement operation, the rotor 1 of the stepping motor is driven at a small step angle.

[Effects of the Invention] As explained above, the electric motor of the present invention has two disk-shaped magnets, one surface of which is magnetized with N pole and the other surface magnetized with Sfi, which are coaxially connected to form a rotor. Salient poles that equally divide the circumference are provided on both sides of the magnet, and a comb-shaped stator yoke is placed opposite the salient poles, making it possible to generate torque on both sides of the disc-shaped magnet rotor. Therefore, the motor can be flat and have a large output without having to be elongated in the axial direction as in conventional electric motors. In addition, since the disc-shaped magnet rotor is magnetized with one surface being magnetized to the north pole and the other surface being magnetized to the south pole, it is possible to create salient poles by providing many unevenness on both sides of the disc-shaped magnet rotor. Furthermore, since the teeth of the stator yoke are on the same plane as the magnetic pole plates, high-precision machining is possible according to the number of salient poles of the disc-shaped magnet rotor. It has a positive effect.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of one embodiment of the present invention, FIG. 2(A) is a front view of the rotor, FIG. 2(B) is a side view of the rotor, and FIG.
Figure (a) is a front view of the stator yoke, Figure 3 (b) is a partially enlarged view of the stator yoke in Figure 3 (a), and Figures 4 (a), (b), (c), and (d) are of the rotor. A developed view of the teeth of the stator yoke and the salient poles of the disc-shaped magnet rotor to explain the operation, FIG. 5 is a drive timing diagram of the stator coil, and FIG. 6 is a side sectional view of a conventional stepping motor.
FIG. 7 is an exploded perspective view of a conventional stepping motor. l... Rotor, (20, 22)... Disc-shaped magnet, 2
6... Salient pole, 3... Rotor shaft, (50, 52
, 60, 62)... Stator yoke, (50b, 52
b, 60b, 62b)...Teeth portion of stator yoke, (80,82)...Bobbin frame, (90,92)...
...Stator coil, Figure 1 Figure 20 (A) Figure 2 (B) 4th port (A) Figure 4 (B) 40 (C) 1-20 1-11-11-22 - Figure 4 (d) 11111→-' 52b 1~ □22 ・ ・ 62b Figure 5 M7 Figure 6

Claims (2)

[Claims] (1) A rotor in which the centers of two disks are coaxially connected, with one side magnetized as N pole and the other side as S pole, and the circumference is equally divided between the outer peripheries of both sides of each disk. A rotor in which salient poles are provided radially toward the center of the disk, two stator coils wound around the outer periphery of each of the disks with a slight gap between them, and each of the stator coils sandwiched from both sides. The stator yoke is a disc-shaped stator yoke, and includes a stator yoke that is provided with comb-shaped teeth portions that face the salient poles of the disc with a slight gap in between and equally divide the circumference at the same pitch as the salient poles. An electric motor characterized by: (2) The pitch of the salient poles is 1/2 pitch on the front and back of the disk,
The electric motor according to claim 1, wherein the discs are shifted by 1/4 pitch, and the pitch of the teeth is shifted by 1/2 pitch on the front and back of the disc, and the pitch of the teeth is the same.