JPS6341827Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement to the field magnet device of a magnet motor. A conventional device of this type is shown in Fig. 1. In the figure, 1 is a magnet motor, 2 is a field magnet assembly, and is composed of field magnet poles 4 fixed with adhesive to the inner peripheral surface of a yoke 3 formed into a cylindrical shape from a soft steel plate member. The field magnet poles 4 are usually made of strontium ferrite permanent magnet material. 5 is the field magnet pole 4.
It is an armature pivotally mounted for free rotation in the inner peripheral space of a rotor 5. When the armature 5 is energized by an external power supply device, such as a battery, it rotates by receiving the excitation force of the field poles 4. In Fig. 2, if the horizontal axis represents the strength of the magnetic field and the vertical axis represents the magnetic flux density, when the field poles 4 have demagnetization characteristics, the armature reaction magnetic flux caused by energization of the armature 5 exceeds the bending point F and acts on the field poles 4 up to the vicinity of point P shown in the figure, causing a drawback that the permanently magnetized magnetism causes irreversible demagnetization.

The present invention eliminates the drawbacks of the prior art by attaching a ferromagnetic material to the field poles that reduces the armature reaction flux.

Embodiments of the present invention will be described below with reference to the drawings. In FIGS. 3a and 3b, 1 is a magnet type motor, and 2 is a field assembly, which is fixed with adhesive to the inner peripheral surface of a cylindrical yoke 3 made of a mild steel plate member. It consists of 4 magnetic poles. The field poles 4 are made of permanent magnets, and are formed to protrude beyond the axial length LC of the armature core 8 constituting the armature 5. Soft iron plates 6 and 7 made of a ferromagnetic material having a lower magnetic resistance than a permanent magnet are fixed along the inner peripheral surface of the field pole 4. The soft iron plates 6 and 7 are
The field poles 4 are arranged nearer to the end of the armature core 8 than the axial end of the field pole 4 and over a portion that is inwardly upper.

In addition, in the figure, 9 is the armature coil, 10 is the rotating shaft,
11 is a commutator.

Since the field device is configured in this way, when the armature 5 is energized, it rotates under the excitation force of the field poles 4, but the reaction magnetic flux Φa of the armature 5
Since the flux flows through the soft iron plates 6 and 7 fixed to both ends of the inner peripheral surface of the field pole 4, the demagnetizing magnetic flux flowing to the permanent magnets forming the field pole 4 is extremely reduced. Become. Furthermore, the excitation flux of the permanent magnet, which is the main magnetic flux of the field assembly 2, flows through the soft iron plates 6 and 7 as shown in Φb in the part overhanging the armature core 8 from both ends in the axial direction. It flows into the iron core 8, and the amount of excitation flux of the main magnetic flux increases.

In addition, since the soft iron plates 6 and 7 are provided at both ends of the field pole 4, not only do eddy currents hardly flow, but there is little overlap with the armature core 8 in the radial direction, so the armature core 8 There is little pulsation in the magnetic flux density received from the magnetic field, and eddy current loss is low.

As described above, according to the present invention, a ferromagnetic material having a lower magnetic resistance than a permanent magnet is fixed to the inner peripheral surface of both axial ends of the field poles, so demagnetization of the permanent magnet is alleviated and the armature characteristics are improved. Not only is it enhanced;
This has the effect of reducing eddy current loss.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the main parts of a conventional device, Fig. 2 is a diagram showing a demagnetization characteristic curve showing the characteristics of the conventional device, and Fig. 3a is a plan sectional view of the main part showing an embodiment of the present invention. , FIG. 3b is a sectional view taken along line A--A in FIG. 3a. In the figure, 1...Magnetic motor, 2...Field assembly, 3...Yoke, 4...Field magnetic poles, 5...
Armature, 6, 7...soft iron plate, 8...armature core. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] It is equipped with a field device in which field poles made of permanent magnets are fixed to the inner peripheral surface of a cylindrical yoke, and an armature rotatably provided in the inner peripheral space of the field device. The magnetic pole is provided to protrude from the armature core in the axial direction, and the ferromagnetic material having a lower magnetic resistance than the field magnetic pole is fixed along the inner peripheral surface of the field magnetic pole.
A field device for a magnetic motor, characterized in that field poles are disposed from an axial end to an armature core end or an upper inward position.