JPS602865B2 - Fixing method of permanent magnet field - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC machine having a permanent magnet as a field, and more particularly to a fixing method for fixing a magnetic pole piece and a permanent magnet to a yoke by welding using a non-magnetic holding plate. It is.

Conventionally, in a permanent magnet field in which a permanent magnet is inserted between a magnetic pole piece and a yoke, the magnetic pole piece and the permanent magnet, and the permanent magnet and the yoke are connected using an adhesive or by directly welding them. , but if adhesive is used, it is necessary to prepare the adhesive composition and the joint surfaces of the pole pieces, permanent magnets and yoke, such as degreasing and polishing.
``The subsequent application process is complicated, and unlike ordinary welding, direct welding of permanent magnets requires Since the material of the magnet is sintered from various metals, it cannot withstand the welding impact and collapses, or even if it can be welded, it cannot obtain the required strength, and its holding power is greatly reduced by the welding heat. This made welding difficult.

The present invention has been made to eliminate such drawbacks, and will be described below with reference to an embodiment shown in the drawings.

In FIG. 1, 1 is a magnetic pole piece, 2 is a permanent magnet, 3 is a yoke, 4 is a rigid holding plate made of a non-magnetic metal, and la
4a is the surface of the magnetic pole piece 1 on the permanent magnet 2 side, 4a is the contact surface of the retaining plate 4 with the magnetic pole piece, and W is the welding location.

The magnetic pole piece 1 and the permanent magnet 2 are arranged in a yoke 3 and held by a jig (not shown), and the retaining plate 4 is placed on the side surface of the magnetic pole piece 1 so that it protrudes from both la of the permanent magnet side of the magnetic pole piece 1. Let me relax,
The surface la of this magnetic pole piece 1 and the surface 4a of the retainer plate 4 that abuts the magnetic pole piece 1 are fillet welded.

Therefore, a tensile force is applied to the magnetic pole piece 1 in the direction toward the permanent magnet (arrow A) due to the strong thermal contraction force generated when the weld bead cools, and the permanent magnet 2 is squeezed between the magnetic pole piece 1 and the yoke 3. Hold. FIG. 2 shows another embodiment of the present invention, in which the holding plate 4 is formed into an annular body having a hole or space in the center for passing a rotor (not shown). 4 is welded to the side surface of the magnetic pole piece 1 with the side surface of the magnetic pole piece casing. do.

Therefore, the magnetic pole pieces are pulled toward the permanent magnet by cooling the weld bead. Furthermore, FIG. 3 shows the case of a rotating field type, which is similar to the embodiment shown in FIG.

Although the above embodiment shows the case of two poles, the permanent magnet can be held under pressure in the same way in the case of multiple poles.

In this way, the present invention straddles the opposing magnetic pole pieces.
A holding plate is provided on the side of both magnetic pole pieces, and the magnetic pole piece and the holding plate are fillet welded, so that the magnetic pole piece and the permanent magnet can be connected to the yoke as in the conventional method. There is no need to weld to the permanent magnet, and there is no need for pre-treatment or drying of each joint surface, and the welding process is easy and yields can be improved. Since it does not weld with iron, the steel plate can be used as L vertical iron.
The ability to use inexpensive ductile cast iron also provides significant benefits in terms of work and materials.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 8 is a front sectional view showing one embodiment of the invention, and FIGS. 2 and 3 are front views showing essential parts of other embodiments of the invention.

Kawama magnetic pole pieces, milk permanent magnets 3 is the yoke holding plate, a is the surface of the magnetic pole piece on the permanent magnet side, 4a is the contact surface of the holding plate with the magnetic pole piece ~ 4b is the contact surface of the holding plate This is the end face on the opposite side of the permanent magnet.

Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. In a permanent magnet field in which a permanent magnet is provided between a yoke and a magnetic pole piece, a rigid non-magnetic metal that is in contact with the sides of both magnetic pole pieces is placed between the opposing magnetic pole pieces. A retaining plate is provided, and each of the magnetic pole pieces and the retaining plate are fillet welded to the permanent magnet mounting surface of the magnetic pole piece or the opposite end face of the retaining plate to the permanent magnet, and the permanent magnet is welded by the shrinkage force of the weld bead when it is cooled. A method of fixing a permanent magnet field characterized by interposing it between a magnetic pole piece and a yoke. 2. The method of fixing a permanent magnet field according to claim 1, wherein the retaining plate is welded while the magnetic pole piece is pressed against the yoke via the permanent magnet.