JPS5910160A - Dc motor - Google Patents

Abstract

PURPOSE:To reduce cogging in a DC motor by winding on the entire periphery of the opposed part of permanent magnets of an armature core with a thin plate of high magnetic permeability. CONSTITUTION:A DC motor has a permanent 1, a yoke 2, an armature coil 3 and an armature core 4. A thin plate 10 of high magnetic permeability is wound on the entire periphery of the opposed part of permanent magnets 1 of the core 4. The thickness of the plate 10 is set to 50% or less as compared with the air gap between the magnets 1 and the core 4, and the sectional area of amagnetic path is set to 10% or less as compared with that of the coil unit of the core using laminated silicon steel plates.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC motor characterized in that a thin plate having a high magnetic permeability π is wound around a part of an armature core facing a permanent magnet.

The structure of the armature core of a conventional DC motor is shown in Figure 1 “K
As shown, it consists of a permanent magnet 1, a yoke 2, an armature winding 5, and an armature core, and the armature is provided with a slot for winding, and the permanent magnet or the electric machine is connected. Because of the slot, the magnetic resistance of the permanent magnet and the N-root iron core changes, causing cogging that causes rotation. In the IP flow motor shown in Figure 1, the closer the air gap between the armature core and the permanent magnet is, the more the air gap magnetic flux increases, but the amount of change in magnetic flux due to changes in magnetic resistance also increases, causing cogging. will increase. When a ferrite magnet is used as a permanent magnet, the energy product of the ferrite magnet is relatively small ζ (because the air gap magnetic flux is not very large, the torque due to cogging is also small compared to the starting torque π of the DC motor in which the ferrite magnet is used) However, when a rare earth magnet is used, the energy product of the rare earth magnet is much larger than that of the ferrite magnet, and the air gap magnetic flux also increases, causing a problem of cogging. In the case of a magnet rotating electric motor, ferrite magnets require a larger weight than rare earth magnets, so the rotor using ferrite magnets has a greater moment of inertia, which alleviates cogging. However, in order to obtain high torque 1, it is better to use rare earth magnets. Fig. 2 shows a schematic diagram of a flat type DC motor. 5 is a rotor magnet, 6-piece rotor yoke, 7 is a stator coil, 8-piece stator yoke, This type of DC motor does not have a slotted I-connection iron, so coking does not occur.The air gap between the rotor magnet and the stator yoke is very close to the magnetic It is difficult to obtain high torque without using performance effectively, and it is also difficult to save power.

The present invention eliminates such drawbacks, and its purpose is to reduce cogging in an electromagnetic iron, square type DC motor capable of obtaining high torque.

The present invention will be described in detail below based on Examples.

In Fig. 3, there is a 1-piece permanent magnet, 2-piece yoke, 3Vi armature winding, 4-piece armature iron (Cr), and a +01-1 magnetic ring. The reason why a rare earth magnet is used as a permanent magnet is that it can obtain an air gap magnetic flux 2 to 4 times that of a Zuba ferrite magnet. Figure 4 is a diagram showing the position of the magnetic ring.The magnetic ring is made by winding a piece of 111 iron I (r) with a high ζ scale height around the outer circumference of the magnetic ring. Using a magnetic material, the plate thickness shown in Figure 3 should be 50 inches or less compared to the air gap between the permanent magnet and the ms child core, and a laminated silicon steel plate with a magnetic path cross-sectional area of 1' as shown in Figure 4 was used. The winding part of the armature core (take less than 10 inches compared to the area).
From Ti li), it is possible to reduce cogging due to armature core slots to less than half, and by closing the gap between the permanent magnet and the magnetic ring, the permanent magnet can be used with a high permeance coefficient. With a sharp heel, you can get high torque and save power.

By cutting the armature iron knob structure using the magnetic ring of the present invention as shown in the LJ, cogging of the DC motor can be reduced, which is useful for high torque characteristics and power saving. Small motors that require high rotational accuracy (small speed fluctuations) and high torque, such as motors for driving magnetic recording media in magnetic recording devices, such as rotary head cylinder drive motors in video tape recorders, and phono motors in record players. It is useful if applied to

[Brief explanation of the drawing]

Figure 1 is a schematic diagram including the structure of the armature core of a conventional DC motor. Figure 2 is a schematic diagram of a conventional flat type DC motor. Figure 3 is a schematic diagram including the structure of the armature core of the DC motor of the present invention. FIG. 4 is a diagram showing the relationship between the armature iron part and the magnetic ring. 1 is a permanent magnet 2 is a yoke 3 iJ electronic winding 4 is an armature core 5 is a rotor magnet 610-11 7-piece stator coil 8 is a stator yoke 9-piece board
10 or more magnetic rings Applicant: Suwa Seikosha Co., Ltd.

Claims (1)

[Claims] In a DC motor consisting of at least a permanent magnet, an armature core, and an armature winding, it is recommended that a thin plate with high magnetic permeability be wrapped around the entire circumference of the armature core at the part facing the permanent magnet. Characteristic DC motor.