JPS5996858A - Dc motor - Google Patents

Abstract

PURPOSE:To rigidly and accurately mount a permanent magnet on a yoke ring by forming notches to be engaged with permanent magnets at the yoke ring side and forming a groove matched at the notch at the permanent magnet side. CONSTITUTION:Permanent magnets 20 are arranged circumferentially of a yoke ring 15 to form a rotor. Notch 16 to be engaged with permanent magnets are formed at the ring 15 side, and grooves 19 are formed to be matched to the notches 16 at the permanent magnet 20 side. The permanent magnets 20 are formed as flexible rubber magnets. The ring 15 is coupled to the magnets 20 by engaging the magnets 20 with the notches 16 of the ring 15.

Description

[Detailed description of the invention] (a) Technical field of the invention The present invention relates to a DC motor.

(b) Technical Background The motor is intended for use in information processing input/output terminals, such as disk drive motors for floppy disk devices, and is designed to be easy to mount on printed circuit boards, has a small flat structure, and has an output This is a high torque motor.

The present invention particularly presents means for attaching permanent magnets to the rotor (hereinafter referred to as rotor).

(C) Problems with the Prior Art Fig. 1 is a side view showing the overall configuration of a DC motor, and Fig. 2 is a perspective view (a) and a cross-sectional view (opening) of the rotor in Fig. 1.
The configuration outline and problems will be explained according to both drawings.

Reference numeral 1 in FIG. 1 denotes a motor stator, which has a field core formed by punching and forming a soft magnetic thin iron plate into a donut shape as a base, and a plurality of field coils 6 are wound around the circumferential surface of the field core.

Reference numeral 2 denotes the rotor of the motor, and its structure will be made clearer from FIG.

3 is a permanent magnet attached to the axial center side of the yoke 12 forming the base of the rotor 2, and 4 is a permanent magnet attached to the outer circumferential side of the yoke of the rotor. 5 is a rotating shaft portion, and 6 is the above-mentioned field coil.

Numerals 7 and 8 are slots for winding the coil, and the space between the adjacent slits becomes the field magnetic poles 10 and 10' of the stator.

The field magnetic pole 10 of the stator includes a rotor-side permanent magnet 4,
Field magnetic poles 10' are provided with magnetic circuits that are electromagnetically coupled to the rotor-side permanent magnets 3, and the stator 1
Motor drive torque is generated on the inner and outer circumferential surfaces of the motor.

FIG. 2 shows the arrangement of the permanent magnets 3 and 4 mounted on the rotor side. For example, magnets 13 and 14 on the same radial direction separated by a dotted line in FIG. 2 have NS magnetic poles in the same direction. However, the magnetic pole directions of adjacent magnet bodies are reversed.

Therefore, the two-phase angle is 90° with respect to the field coil 6 of the stator.
By applying a four-phase pulse current of , a rotating magnetic field for driving the rotor is generated.

By the way, the conventional mounting of the permanent magnet is #l! The outer peripheral part 12' and the inner peripheral part 12 of iron are provided with a collar that is bent upward to form a yoke ring, and the outer ring 12'
A magnet 4 was fixed to the inner side of the inner ring 12, and a magnet 3 was fixed to the outer side of the inner ring 12 with a resin adhesive. However, while the former permanent magnet 4 is easy to attach, the latter permanent magnet 3 bonded to the inner ring has the disadvantage that it is likely to fall off from the ring due to the centrifugal force accompanying the rotation of the rotor.

(d) Purpose of the Invention The purpose of the present invention is to eliminate the above-mentioned drawbacks and mount a permanent magnet firmly and accurately.

(e) Structure of the Invention The above object includes a stator comprising a plurality of field coils for generating a two-rotation magnetic field, and permanent magnets electromagnetically coupled to the field coils arranged in the circumferential direction of a yoke ring. In order to install the permanent magnets on the rotor side of the rotor and the DC motor, there is a notch on the yoke ring side for the permanent magnet to fit in, and a groove on the permanent magnet side that matches the notch. The molded attachment is achieved as a structure.

<r> Embodiments of the invention Examples of the invention are shown in FIGS. 3 to 5, and the invention will be described in detail with reference to FIG.

FIG. 3 is a perspective view of the yoke ring without the rotor side base of the DC motor. 4 is a perspective view of a permanent magnet fitted into the yoke ring of FIG. 3; FIG.

In the perspective view of the yoke ring, reference numeral 15 denotes the yoke ring of the present invention, which is a permanent magnet mounting portion corresponding to 12 above. A plurality of magnet-receiving cutouts, indicated at 16, are cut into this. The notch becomes a part into which the connecting part 18 of the magnet molded body 20 shown in FIG. 4 fits.

FIG. 4 shows a permanent magnet molded body 20 which constitutes another essential part of the present invention.
It is. The molded body is molded as a flexible rubber magnet. The molded rubber magnet body 2o is.

Both figures are provided with a groove 19 that is fitted into the flange thickness 17 of the yoke ring (inner ring) 15 and fixed. The grooves 19 and the like having such a shape can be freely formed using a mold shape for molding a rubber magnet.

FIG. 5 shows the rubber magnet body 2o fitted into the notch of the inner ring 15. Of course, by doing this, it is easy to attach the permanent magnet 3.

Permanent magnets will not fall off due to centrifugal force.

If the permanent magnet 4 on the side of the yoke ring 12' in Fig. 2 is also made of the above-mentioned rubber magnet, it will be more reliable with a simpler adhesive method because of the rubber magnet's elastic restoring force and centrifugal force during rotation. Fixed.

FIG. 5 is a perspective view of the rubber magnet assembly mounted on the inner ring 15. As shown in the figure, the rubber magnet 20 has magnetic poles formed in the radial direction by dividing the entire circumference at equal angles (axis center angle: 45°). An example of magnetization in which the north and south poles appear alternately is illustrated.

The outer circumferential magnetic pole in the illustrated state is in contact with the field pole 1° of the stator and contributes to motor torque generation as in the conventional case. In addition, the inner circumferential magnetic pole can be used as a magnetic field for detecting the shaft position of motor rotation by installing a Hall element (not shown), or as a magnetic field for extracting pulses proportional to the rotation speed, and is used for servo control, which is essential for this type of motor. Serve as a means of control.

For example, the number of divisions (eight divisions) of the permanent magnet provided on the rotor yoke side used in the embodiment of the present invention described above is only one example.

(g) Effects of the invention According to the magnet mounting means of the invention described in detail above,
By inserting a grooved rubber magnet into a yoke ring that has a notch that is integrated with the rotor, permanent magnets can be installed (
(assembly) becomes easy. However, the inner circumferential magnetic pole of the magnet also has a secondary advantage that is extremely convenient for acquiring the motor servo information (rotation information).

[Brief explanation of the drawing]

FIG. 1 is a side view showing the overall configuration of a DC motor. FIG. 2 is a perspective view (A) and a sectional view (B) of the rotor in FIG. FIG. 3 is a perspective view of a yoke ring forming the rotor side base body, which is an embodiment of the present invention, FIG. 4 is a perspective view of a rubber magnet fitted into the yoke ring of FIG. 3, and FIG. It is a perspective view of a rubber magnet assembly. In the figure, 1 is a stator, 2 is a rotor, 3 and 4 are conventional permanent magnets, 5 is a rotating shaft, and 6 is a field coil. 12 is a yoke, 15 is a yoke ring of the present invention, 16 is a notch of 15, 19 is a groove, and 20 is a molded magnet (rubber magnet) of the present invention. Figure 3 A

Claims (2)

[Claims] (1) A DC motor consisting of a stator including a plurality of field coils that generate a rotating magnetic field, a rotor in which permanent magnets electromagnetically coupled to the field coils are arranged in the circumferential direction of a yoke ring. The structure for mounting the permanent magnets on the rotor side is such that the yoke ring side has a notch for inserting the permanent magnet, and the permanent magnet side has a groove that matches the notch. A DC motor characterized by: (2) A patent characterized in that the permanent magnet electromagnetically coupled to the field coil is formed of a rubber magnet.