JPH02290147A - magnetic dc machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a magnetic DC machine, particularly one in which an auxiliary pole made of a magnetic material such as a mild steel member is fixed as a field pole.

[Conventional technology]

In the conventional device, as described in Japanese Patent Publication No. 63-55303, the magnetic poles include a permanent magnet of the main pole, an auxiliary pole at the end of the increasing field side, and a permanent magnet material at the end of the auxiliary pole on the increasing field side. It had a magnetic pole structure with another auxiliary pole.

[Problem to be solved by the invention]

In the above conventional technology, an auxiliary pole is provided on the magnetizing field side of the field pole, and another auxiliary pole made of a permanent magnet material is provided at the end of the auxiliary pole on the magnetizing side to prevent a sudden increase in magnetic flux density. Regarding the structure, there were problems such as an increase in the number of parts, no consideration was given to assembly productivity, and an increase in manufacturing costs.

The present invention aims to prevent a rapid increase in magnetic flux density in the auxiliary pole portion while reducing the number of parts, and also aims to provide a cheaper product. [Means for solving the problem] In order to achieve the above object, the radial thickness of the auxiliary pole is changed depending on the position on the increasing field side, and the air gap with respect to the armature outer diameter is gradually changed depending on the position on the increasing field side. It is.

[Effect]

The magnetic flux density of the mild steel auxiliary pole placed in parallel with the permanent magnet rapidly increases due to the magnetizing effect of the armature reaction. Therefore, in order to gradually change the air gap between the auxiliary pole and the armature and suppress a sudden increase in magnetic flux density, the radial thickness of the auxiliary pole is changed depending on the position of the magnetizing field due to the armature reaction. The magnetic resistance is adjusted to suppress sudden changes in magnetic flux density.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In the figure, 1 is the field pole of the magnetic DC machine, which is fixed to the inner peripheral surface of the cylindrical yoke 2. 3 is constituted by a permanent magnet material which is a main magnetic pole disposed from the magnetic pole center axis 0-0 toward the demagnetizing side end of the armature reaction magnetic flux, and the permanent magnet is magnetized.

Reference numeral 4 denotes an auxiliary pole disposed on the side of the magnetic field where the armature reaction magnetic flux acts, and is made of a magnetic material having a magnetic permeability greater than the reversible magnetic permeability of a permanent magnet material such as a mild steel member. Reference numeral 5 denotes an armature which is rotatably mounted in the inner periphery of the field magnet pole 1, and is arranged with a gap g between it and the inner periphery of the field magnet pole.

The main magnetic pole 3 and the auxiliary pole 4 are constructed so as to come into contact with each other at a point P in the figure.

Furthermore, to explain the air gap between the auxiliary pole and the armature,
Figure 1 shows that the gap gi>gz becomes larger toward the end of the magnetization side, and the second
In the figure, gs<gz. Further, in FIG. 3, the auxiliary electrode is constructed so that, with respect to the main part gap g1, both ends thereof have a relationship of g2 and g1<gz.

Next, the operation of the above configuration will be explained.

An armature coil (not shown) wound around the armature 5 is energized, receives the excitation force of the field pole 1, and the armature 5 generates rotational force. Next, a developed diagram of the magnetic flux distribution generated between the field magnetic pole 1 and the armature 5 in the above case is shown in FIG. 1b. In the graph of FIG. 1b, the vertical axis represents the magnetic flux density, and the horizontal axis represents the circumferential position of the air gap formed by the field pole 1 and the armature 5. 6 is a graph showing the magnetic flux density of the air gap,
The diagram shows the field flux on the right side of the diagram from point P, that is, the excitation flux acting on the armature 5 from the auxiliary pole 4, and the field flux that acts on the armature 5 from the auxiliary pole P point is suppressed. The purpose is to effectively utilize the reaction magnetic flux.

Figure 2b shows that the greatest increase in magnetic flux density is seen at the end of the auxiliary pole on the magnetic field side, but in order to suppress the rapid increase at the end, the size of the air gap is changed to effectively utilize the reaction magnetic flux. And so.

In Fig. 3b, the air gap is set small at the center in order to effectively utilize the reaction magnetic flux at the center while suppressing the rapid increase in magnetic flux density at both ends of the auxiliary pole.

As another example, it is also effective to set the gap gt>gz as shown in FIG. 3A. Furthermore, for the air gap g with the main pole,
The requirements for g>gz e g=gt or g<g1 can be set freely depending on the required state of the DC machine. [Effects of the Invention] This invention was made to solve the above-mentioned drawbacks of the conventional device, and it partially changes the air gap length for the auxiliary pole armature, thereby reducing the magnetizing field generated by the armature reaction. The magnetic flux distribution changes gently without sudden increases or decreases, which prevents magnetic noise and improves the demagnetization characteristics at the end of the main magnetic pole demagnetized field, and improves performance by improving rectification. This makes it possible to extend the life of the brush.

Furthermore, in the manufacturing method, the auxiliary electrode can be easily molded using conventional techniques, so it can be obtained at low cost.

[Brief explanation of the drawing]

FIG. 1(a) is a cross-sectional view of a stator showing a main part of an embodiment of the present invention, FIG. 1(b) is a graph for explaining the magnetic characteristics of FIG. 1(a), and FIG. (a) (b) and Figure 3 (a)
)(b) is a diagram showing another embodiment.

Claims (1)

[Claims] 1. It has a field magnetic pole composed of a main magnetic pole made of a permanent magnetic material and an auxiliary pole made of a magnetic material having a magnetic permeability higher than the reversible magnetic permeability of the permanent magnet material. The auxiliary pole is provided at the end of the main magnetic pole on the magnetizing side, and the auxiliary pole has a thickness such that the relationship of the air gap length to the armature differs depending on the position on the magnetizing field side. A magnetic DC machine characterized by having different dimensions. 2. For the gap length g_1 under the main pole, the minimum gap length g_2 of the auxiliary pole is g_1>g_2, g_1=g_2, g_1<
g_2 A magnetic DC machine that satisfies either of the following relationships.