JPH01136548A - Stepping motor - Google Patents

Abstract

PURPOSE:To make it possible to attain its lightweight and compact design by lengthening a rotor in the direction of a shaft, applying multipolar anisotropic orientation and integrating a rotor shaft and power transferring gears or the like into one unit. CONSTITUTION:A multipolar anisotropic orientation resin magnet rotor 1 is made of a material mixed with thermoplastic resin and magnetic powder, and at the same time, the anisotropic field orientation is applied to integrate a rotor shaft 1A of a non-orientation section and power transferring gears or the like into one unit. Yoke members 5L1 and 5L2, 5R1 and 5R2 are placed on both sides of the rotor 1 in opposite directions. Yoke members 5L1, 5L2, 5R1 and 5R2 have stator teeth 4 as a stator, and electromagnetic coils 6A and 6B to generate magnetic field at the stator teeth 4 are mounted on yoke members 5L1, 5L2, 5R1 and 5R2.

Description

[Detailed Description of the Invention] [Industrial Applications] The present invention relates to a stepping motor, and more particularly to a small, multipolar stepping motor having a rotor, a stator yoke, and an electromagnetic coil. .

[Prior Art] In a conventional stepping motor that has a magnetic field in the radial direction around the outer circumference of the rotor, a sintered ring-shaped magnet is used to form a radial orientation, the outer circumference is magnetized and oriented, and the magnet is press-fitted or bonded to the shaft member. Generally, the rotor is constructed by being fixed with a

[Problems to be solved by the invention] Recently, there has been a demand for miniaturization of this type of motor. Rotor magnetic pole pitch (2~3m
Since the disassembly performance deteriorates with spacing of m), a rotor with a smaller diameter is also required to have a similar number of magnetic poles. However, as the number of disassembled rotor magnetic poles with a reduced outer circumferential diameter increases, the pitch between the poles (1.4 to 1.Bmm+) becomes narrower, making it impossible to manufacture using conventional technology.

Therefore, resin-molded magnets have been studied in the past, but there has been a problem that magnetization is incomplete and the magnetic force is weak for rotors with a small pitch between poles (1.4 to 1.8 mm).

The present invention attempts to solve these problems.

That is, the present invention provides a stepping motor which is made of a small-diameter rotor, which has a long axial length, is anisotropically oriented with multiple poles, and is molded integrally with the shaft so as to obtain sufficient torque and disassembly performance. The purpose is to provide motors.

[Means for solving the problem] The material is made of a material obtained by kneading thermoplastic resin and magnetic powder, and anisotropic magnetic field orientation is applied in the molding machine so that the rotor shaft and power transmission gears in the non-oriented part are a yoke member disposed to face both sides of the rotor, and a stator arranged in the axial direction of the rotor from the yoke member; The stator tooth is provided with an electromagnetic coil that is attached to the yoke member and generates a magnetic field in the stator tooth.

[Function] According to the present invention, the rotor can be lengthened in the axial direction and can be configured integrally with the rotor shaft and gears for power transmission by applying multi-pole anisotropic orientation. By arranging the stator teeth and stator yoke on the left and right sides of the rotor, and by fixing the electromagnetic coil that generates a magnetic field in these stators to the stator yoke, the entire stepping motor can be made lighter and smaller. Moreover, it can generate sufficient torque and has a wide degree of freedom in design.The smaller rotor allows the moment of inertia to be kept small, resulting in excellent starting performance and responsiveness. , controllability can be improved. Furthermore, since the multipolar anisotropically oriented resin magnet rotor, the rotor shaft of the non-oriented part, and gears for power transmission are integrated, there is no need for press-fitting or gluing processes, and thermoplastic resin and magnetic powder This material has good moldability and can be manufactured at low cost.

[Example] FIG. 1 is an exploded perspective view showing an embodiment of the present invention.

In FIG. 1, 1 is a multipolar anisotropically oriented resin magnet rotor in which a plurality of magnetic poles N and S are alternately magnetized on the outer peripheral surface;
IA is its rotor axis. The rotor shaft IA is pivotally supported by a bearing portion 2A of a motor support plate 2 and a bearing portion 3A of a bearing plate 3.
The iron core 7 has a plurality of stators 4 formed in a comb tooth shape and has a yoke member 5L1, 5L2 and an electromagnetic coil 6A wound thereon, and a similar yoke member 5R1, 5R2 and an electromagnetic coil 6B are wound thereon. Iron core 8 and
It is fixed by caulking means or screwing means.

Further, 2B and 3B are holes drilled in the motor support plate 2 and the bearing plate 3 in order to penetrate the iron core 7.8 and caulk the tip thereof, and 5A is the hole bored in the yoke member 5L.
1 (5), 5 L 2 (5).

These are caulking holes for fixing 5 R1 (5) and 5 R2 (5).

FIG. 2 is an enlarged perspective view of the rotor, and FIG. 3 shows the operation of the stepping motor having the multipolar anisotropically oriented resin magnet rotor 1 shown in FIG.

That is, in the stepping motor of this embodiment, in the four stages of FIG. 3(a) → FIG. 3(b) → FIG. 3(8) → FIG. 3(d) → FIG. , 174P
(P is the pitch), the rotor 1 rotates, and FIG. Since the magnetic poles form a magnetic path via the stator and the yoke member, the stator teeth 4 of the left yoke member 5L1
Stator teeth 4L2 of L1 and yoke member 5L2 are stopped facing magnetic poles S and N of rotor 1, respectively.

On the other hand, the stator teeth 4R1 of the right yoke member 5R1 and the stator teeth 4R2 of the yoke member 5R2 do not face the magnetic poles S and N of the rotor 1, but are half poles, that is, 1/2.
In this way, the right yoke phase and the left yoke phase are set to be deviated by 1/2P.

That is, the pitch P is the magnetized magnetic pole pitch in the rotor 1, and therefore, in this case, the angle θ shown in FIG.
Also, the pitch between the stator teeth 4L1 and 4L2 constituted by the yoke members 5L1 and 5L2 and the yoke member 5R1.
, 5R2, the pitch between the stator teeth 4R1 and 4B2 corresponds to the pitch P described above.

Next, as shown in FIG. 3(n) from the state of FIG. 3(a), the electromagnetic coil 6A is energized in the opposite direction (this state is changed to B).
), and when the electromagnetic coil 6B is energized in the positive direction (indicated by A in this state), an N pole is generated at the stator tooth 4L1, an S pole is generated at the stator tooth 4L2, and the fixed An S pole is generated in the child tooth 4R1, and an N pole is generated in the stator tooth 4R2. In this way, the rotor 1 can be rotated in a counterclockwise direction due to mutual repulsion and attraction between the poles on the rotor 1 and the poles generated on the individual stators. That is, at this time, the left stator teeth 4L1, 4
Since L2 and the stator teeth 4R1 and 4R2 on the right side are shifted by 1/2 P, the poles on the rotor 1 and the poles on the yoke side are shifted from the state shown in Fig. 3 (A) in an attempt to maintain balance. After moving 1/4 point in the counterclockwise direction, it stably stops.

Next, in the state shown in FIG. 3 (b), the electromagnetic coil 6A
When the energization is stopped and the energization A is continued only to the electromagnetic coil 6B to achieve the state shown in FIG. Due to the suction action between the opposing poles of the rotor 1, the rotor 1 further rotates by 1/4 P in the counterclockwise direction.

Next, in the state shown in FIG. 3 (8), the electromagnetic coil 6A
As shown in FIG. 3(d), by applying current B in the positive direction, the rotor 1 is further moved to 1/4P using the same principle.
It can only be rotated counterclockwise.

The series of operating procedures explained above will be further described with reference to FIG. Here, a step sequence is shown in the horizontal direction, and furthermore, the electromagnetic coils 6A and 6 are shown for each step.
The energization state to B is shown. That is, step 8
There are eight combinations of energization from BA to B through steps 1 to S8, and sequence control is performed using these eight steps as one pulse, and by repeating this, the rotor 1 can be moved to any desired angle. It can be rotated. Furthermore, by controlling the energization so that the combination of energizations described above proceeds in the opposite direction, the rotor 1 can be rotated in the clockwise direction. Furthermore, since the rotor 1, the rotor shaft IA, and the gear IB are integrated, the press-fitting and gluing steps for coupling them are omitted.

In the above embodiment, gear IB is used as a power transmission member.
Although this is shown, it is also possible to implement this in the same way even if it is a member such as a cam.

[Effects of the Invention] As explained above, according to the present invention, a yoke member is provided in which stator teeth are formed at opposing positions on both sides of a small multi-pole anisotropically oriented resin magnet rotor. By arranging these stator teeth in combination, and by providing electromagnetic coils that generate a magnetic field via the yoke member on these stator teeth, it is possible to maintain excellent starting performance and control function, and also to achieve high torque. This made it possible to provide a small and lightweight stepping motor. Moreover, it is quite easy to form the rotor, which is integrated with the rotor shaft and gears, to be long in the axial direction, and by combining it with a stator of the opposite length, it is possible to achieve a small size and high torque. Not only that, but also a stepping motor with a small moment of inertia can be provided. In addition, by using a material that is a mixture of thermoplastic resin and magnetic powder, it has good orientation and moldability, making it possible to manufacture the rotor at low cost and reducing its weight. Therefore, it is possible to provide a stepping motor with good followability that is suitable for high-speed motors.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention, FIG. 2 is an enlarged perspective view of a rotor, and FIG. 3 (A). (0), (A), and (d) are explanatory diagrams showing the operating principle of the stepping motor of FIG. 1, and FIG. 4 is an explanatory diagram of the timing of the excitation sequence. 1... Anisotropically oriented resin magnet rotor IA... Rotor shaft IB... Gear 2... Motor support plate 3... Bearing plate 4... Stator 4L1,
4L2, 4R1, 4R2... Stator teeth 5L1. SL2
．． 5R1, 5R2... Yoke members 6A, 6B... Electromagnetic coil 7.8... Iron core (c) (b) (d)

Claims (1)

[Claims] An anisotropic magnet rotor made of a material obtained by kneading thermoplastic resin and magnetic powder is provided with an anisotropically oriented resin magnet rotor integrally molded with a rotor shaft and gears for power transmission, and on both sides of the rotor. A yoke member arranged to face each other, stator teeth serving as a stator arranged in the axial direction of the rotor from the yoke member, and an electromagnetic coil attached to the yoke member to generate a magnetic field in the stator teeth. A stepping motor characterized by comprising: