JPS60183955A - Manufacture of frame for motor - Google Patents

Abstract

PURPOSE:To reduce thermal distortion by attaching the outer surface of the bottom of a heat sink fin to the outer periphery of a frame body, and projection welding the outer surface of the bottom of the fin as a fine strip projection to the body. CONSTITUTION:A metal plate is bent substantially in U-shaped section to form a heat sink fin 11, and the outer surface of the bottom of the fin 11 is attached to the outer periphery of the frame body 13 formed in advance in a cylindrical shape. A fine strip projection 12 is operated as a projection in this state to perform a projection welding. The welding is a method of welding by forming the projection at the portion to be welded, resistance welding and simultaneously pressing it to collapse it.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of manufacturing a frame for an electric motor equipped with heat radiation fins.

[Prior art]

Generally, when operating electromagnetic equipment, the temperature increases due to internal power loss. If this rise exceeds, the deterioration of the insulation will be accelerated,
This will eventually lead to burnout.

For this reason, in electric motors, heat dissipation fins are attached to the outer peripheral surface of the frame body to increase the contact area with air to dissipate internal heat to the outside and prevent temperature rise.

Conventionally, materials made of cast iron or steel plates have been used as frame materials for this type of electric motor.

However, the former method requires a large amount of cast iron, and melting the cast iron consumes a large amount of thermal energy, resulting in an increase in manufacturing costs.

On the other hand, in the latter case, as shown in Figures 1 (a) and (b), the joint part (3) of the rectangular radiation fin (2) is welded to the outer peripheral surface of the frame body (1) by arc welding. Therefore, the inner circumferential surface of the frame body (1) is deformed due to thermal distortion due to welding, and the frame body (1) is deformed before the laminated iron core (5) with slots (4) that will become the stator is press-fitted into the frame body (1). There is a drawback that (1) inner diameter machining is required, which complicates the frame manufacturing work. Another disadvantage is that the weld bead is formed on the outside, resulting in poor appearance.

[Summary of the invention]

The present invention has been made in view of the above-mentioned circumstances and to improve the problem. This is a method of manufacturing a frame for an electric motor, the gist of which is to attach the radiation fin to the outer peripheral surface of the frame body, and to projection weld (protrusion welding) the bottom outer surface of the heat dissipation fin to the frame body as a narrow strip-like projection.

[Embodiments of the invention]

Next, a second method of manufacturing a frame for an electric motor according to the present invention will be described.
An explanation will be given based on an embodiment shown in FIGS. Figure 2 (
a) and (b) show heat dissipation fins used in the present invention; (a)
is a sectional view, and (b) is a side view. FIGS. 6(a) and 6(b) show an apparatus for manufacturing an electric motor frame of the present invention,
(a) is a sectional view, and (b) is a side view.

The symbol (11) in the figure is a heat dissipation fin formed by bending a metal plate into a substantially U-shaped cross section. A heat dissipating fin having a substantially U-shaped cross section is attached to the outer peripheral surface of the formed frame body a, and is made to function as a protrusion by welding (protrusion welding) with the above-mentioned narrow strip-like protrusion. The electric motor frame of the present invention is manufactured.

The projection welding described above is a well-known welding method in which a protrusion is created on the welded part and the protrusion is pressed and crushed at the same time as resistance welding is performed. U is the lower electrode of the resistance welding machine, α [present] is its upper electrode, and the lower electrode (14)
is in contact with the upper part of the inner peripheral surface of the frame body
With the metal inserted and in contact with the inner surface of the heat dissipation fin (11), a predetermined pressure is applied and a predetermined current is applied, and the thin strip protrusion (L7J) on the bottom outer surface of the heat dissipation fin I acts as a protrusion, and the 0th floor of the frame body is Projection welding is performed on the outer circumferential surface.The current applied in this case may be either direct current or alternating current, and heat input may be controlled by repeating energization and rest.Resistance welding has a short energization time; 1 second or less. Therefore, the heat input is extremely low compared to arc welding, and even if a large number of heat dissipation fins are welded to the outer peripheral surface of the frame body a, deformation due to thermal strain is extremely small. 0υ, since the narrow strip-like protrusion aa on the outer surface of the bottom is welded to the outer circumferential surface of the frame body a3 over the entire length, the welded part is uniform and the welded width is wide, about 4 to 8 Ia1, and from the frame body a3. The heat dissipation fins (Iυ) have good heat conduction, and their heat dissipation properties are very good.

In addition, in this embodiment, the heat dissipation fin αυ is attached to the frame body 03.
Although a method of welding the lower electrode α1 and the upper electrode one by one is shown, a plurality of sets of one lower electrode α1 and one upper electrode may be set and welded simultaneously using a plurality of resistance welding machines.

〔Effect of the invention〕

As explained above, according to the present invention, the bottom outer surface of the heat dissipation fin formed by bending a metal plate into a substantially U-shaped cross section is attached to the outer circumferential surface of the frame body previously formed into a cylindrical shape,
Since projection welding is performed by using the thin strip-like protrusions on the outer surface of the bottom of the heat dissipating fins as protrusions, thermal distortion caused by welding of the frame body is extremely small, and processing of the inner diameter of the frame body after welding can be omitted. In addition, since the step of machining the protrusions can be omitted, there is an advantage that the electric motor frame can be manufactured at extremely low cost.

Furthermore, since the welding surface is uniform and wide, heat conductivity from the frame body to the radiation fins is extremely good, and the appearance is also better than with arc welding.

[Brief explanation of the drawing]

Figure 1(&)(b) shows a conventional electric motor frame,
(IL) is a cross-sectional view, and (b) is a side view. Figure 2 (a
) (b) shows a heat dissipation fin used in manufacturing the electric motor frame according to the present invention, (a) is a cross-sectional view, and (b) is a side view. 6(a) and 6(b) show an apparatus for manufacturing an electric motor frame according to the present invention, (LL) is a sectional view, and (B) is a side view. 0υ...Radiation fin, α...mW-shaped protrusion on the bottom outer surface of the heat dissipation fin, (+31...Frame body, ■...
・Lower electrode of resistance welding machine, Q5)... Upper electrode of same. In addition, the same symbols in each figure are the same'! 1' or an equivalent portion. Agent Patent Attorney Sanro Kimura @ Figure 1 (C1) tb) Figure 2 Figure 3 (G) (b)

Claims (1)

[Claims] The bottom outer surface of a heat dissipation fin formed by bending a metal plate into a substantially U-shaped cross section is attached to the outer peripheral surface of a frame body previously formed into a cylindrical shape, and the bottom outer surface of the heat dissipation fin is formed into a narrow strip-like protrusion. A method for manufacturing electric motor frames that uses grogeection welding (protrusion welding) to the frame body.