JPH028542Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a step motor, and by integrally forming the bearing of the rotating shaft and the core around which the coil is wound with a ferromagnetic material, the number of parts is reduced and productivity is improved. Another object of the present invention is to provide a step motor in which the outer diameter of the core is small and the output torque of the motor can be increased.

The present applicant has previously proposed, in Utility Application No. 55-122593 and others, a disk-shaped disk having a plurality of magnetic poles on its axis perpendicular surface, magnetized with different polarities alternately in the circumferential direction, as shown in Fig. 1. A rotor 1, an inner stator which is attached to a yoke fitted with a coil 5 and has a plurality of inner magnetic pole pieces spaced apart and opposed to each other in a plane perpendicular to the axis of the rotor 1, and a gap is provided between the inner magnetic pole pieces and the meshed state. A step motor is proposed which consists of a stator consisting of an outer stator having a plurality of aligned outer pole pieces. In this step motor, a rotating shaft 2 of a rotor 1 is supported by an oil-impregnated bearing 3 whose main component is copper, which is a non-magnetic material, and a core 4 made of a ferromagnetic material formed into a substantially cylindrical shape is attached to the bearing 3. is fixed. A coil 5 is wound around the outer peripheral surface of this core 4.

However, in this conventional step motor, since the bearing 3 and the core 4 are separate, the number of parts increases and productivity is poor. In addition, the core 4 needs to have a volume large enough to prevent magnetization from being saturated by the magnetic field generated in the coil 5, and when the core 4 is fitted and fixed to the bearing 3, the core 4
The disadvantage was that the outer diameter of the

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described with reference to FIG. 2 and subsequent figures.

FIG. 2 shows a sectional view of an embodiment of the step motor according to the present invention. In the figure, the same parts as in FIG. 1 are given the same reference numerals. The step motor shown in the second figure is a two-phase step motor that is configured symmetrically with respect to the central plane perpendicular to the axis of the rotor. In the figure, reference numeral 1 denotes a disk-shaped rotor, and a plurality of fan-shaped sections, which are radially divided into a plane perpendicular to the axis at approximately equal angles, have alternately different polarities in the circumferential direction, and have different polarities in the axial direction. Magnetized. This rotor 1 is fixed to a rotating shaft 2 by a bush 6. The rotating shaft 2 is rotatably supported by a bearing 7. This bearing 7
is an oil-impregnated bearing whose main component is iron, which is a ferromagnetic material, and this bearing 7 has a bearing part 7a and a bearing part 7.
It is composed of a substantially cylindrical core portion 7b integrally formed with the core portion 7a. A coil 8 is wound around the outer circumference of the core portion 7b of the bearing 7, and a ring-shaped yoke 9 having an L-shaped cross section is fitted and fixed to the outer circumference of the bearing portion 7a of the bearing 7. I'm hugging you.

Next, 10 is an inner stator, which, as shown in FIG. 3, has a central base 10a and a plurality of substantially fan-shaped inner magnetic pole pieces 10b extending outward from the base 10a and arranged equiangularly radially. Therefore, the base 10a
The rotating shaft 2 is inserted through the central hole 10c of the base 1.
0a is fitted and fixed to one end of the core portion 7b of the bearing 7. Reference numeral 11 denotes an outer stator, which is composed of a ring-shaped base 11a and a plurality of approximately fan-shaped outer magnetic pole pieces 11b arranged equiangularly radially extending from the base 11a in the axial center direction.
are engaged with the inner magnetic pole pieces 10b at equal intervals, and the base portion 11a is fitted and fixed to one end of the yoke 9. The axially orthogonal surfaces of the inner stator 10 and the outer stator 11 are opposed to each other at a predetermined distance from the axially orthogonal surface of the rotor 1, and the outer peripheral ends of the pair of yokes 9 on both sides of the rotor 1 are approximately cylindrical. A spacer 12 is interposed therebetween, and the rotor 1 is held symmetrically with respect to the central plane perpendicular to the axis of the rotor 1.

As described above, since the bearing 7 is a ferromagnetic oil-impregnated bearing and the bearing part 7a and the core part 7b are integrally formed, the number of parts is reduced, assembly is simple, and productivity is improved. The volume of the conventional core 4
Since the magnetization of the core part 7b will not be saturated if the volume is approximately equal to the volume of By increasing the diameter of the winding, the output torque of the motor can be increased.

As mentioned above, the step motor according to the present invention is
A rotor with alternating polarities in the circumferential direction and magnetized in the axial direction, an inner stator having a plurality of inner pole pieces spaced apart from each other in a plane perpendicular to the axis of the rotor, and an outer stator having a plurality of outer pole pieces. A step motor consists of a coil that is wound around the outer periphery of a core made of ferromagnetic material that is inserted through the rotating shaft of the rotor, and that magnetizes the inner stator and outer stator to different polarities. Since the bearing that rotatably supports the shaft and the core are integrally formed from a ferromagnetic material, the number of parts is reduced, assembly is easy, and productivity is improved, and the outer diameter of the core is small, making it easier to wind coils. This has the advantage that the winding space is large and the number of turns of the coil can be increased or the diameter of the coil winding can be increased to increase the output torque of the motor.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of an example of a conventional step motor, FIG. 2 is a vertical cross-sectional view of an embodiment of the step motor according to the present invention, and FIG. 3 is a cross-sectional view of the step motor shown in FIG. . 1... Rotor, 2... Rotating shaft, 7... Bearing, 7
a...bearing part, 7b...core part, 8...coil,
9...Yoke, 10...Inner stator, 11...Outer stator.

Claims (1)

[Scope of utility model registration request] A rotor having alternately different polarities in the circumferential direction and magnetized in the axial direction, an inner stator having a plurality of inner pole pieces spaced apart from each other in a plane perpendicular to the axis of the rotor, and an outer stator having a plurality of outer pole pieces. A step motor comprising a stator and a coil that is wound around the outer circumference of a core made of ferromagnetic material that is inserted through the rotating shaft of the rotor and that magnetizes the inner stator and the outer stator to different polarities. A step motor comprising a bearing rotatably supporting the rotating shaft and the core integrally formed of a ferromagnetic material.