JPH08182240A - Manufacture of electric rotating machine - Google Patents

Abstract

PURPOSE: To facilitate the positioning of leg part even if the welded part of frame is not positioned at the lowest bottom part. CONSTITUTION: A tubular frame 11 is provide with eight recesses 12a-12c, projecting inward and extending in the axial direction, symmetrically to the lowermost bottom part A. The supporting pieces 13b of a pair of leg parts 13 are secured to two recesses 12a, 12b provided on each side of the lowermost bottom part A at the lowermost part of the frame. The welded part 14 of the frame 11 is positioned between the lowermost bottom part A and the left side leg part 13 contiguously thereto such that it can not be viewed from the outside. When a drainage port 21 is made at the lowermost bottom part A of the frame 11, punching is carried out by means of a press at the part having uniform cross-section and thereby the punching accuracy and machinability are enhanced. Furthermore, the punching die is protected against damage due to application of undue force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a rotary electric machine in which a pair of legs are provided below a frame formed of a metal plate in a cylindrical shape.

[0002]

2. Description of the Related Art Conventionally, there has been provided a rotary electric machine having an arrangement shown in FIG. FIG. 4 shows a vertical sectional front view of the electric motor. In FIG. 4, the stator 2 is attached to the inner circumference of the cylindrical frame 1 by press fitting, and the stator 2
A rotor 4 mounted on the rotary shaft 3 is inserted inward of the rotor. The frame 1 of such an electric motor is formed into a cylindrical shape by joining both sides of a metal plate by welding, and the welded portion 5 is formed of a pair of steel plate legs 6 and 6 attached to the outside of the frame 1. It was located at the bottom bottom of the frame 1 for ease of positioning and ease of automatic assembly.

[0003]

In the above structure, when a drain port for discharging water that has entered the electric motor is provided outside, it must be arranged at the bottom bottom of the frame 1. In this case, the welded portion is required. Since 5 was located at the bottom bottom, it was necessary to make a hole in the weld 5 and install a drainage port.

If the machine has a portion such as a hole, a notch or a projection where the cross section changes abruptly due to its structure, stress concentrates in the vicinity of this portion. Therefore, when the frame 1 is provided with a drainage port, when a load or torque acts in the radial direction on the rotating shaft 3 during the operation of the electric motor and stress is generated in the frame 1,
Stress is concentrated near the drainage port. Further, although it depends on the thickness of the steel plate forming the frame 1, the frame 1
The welding is performed by seam welding in which a part of them is overlapped or by butt welding in which the welding surfaces are butted. Will also concentrate stress.

Therefore, when the drainage port is provided in the welded portion 5, stress is more concentrated and cracks are easily generated in the welded portion 5. Therefore, when the drainage port is provided in the frame 1, the welded portion 5 and the drainage port are separated from each other. It is conceivable to change the position, that is, to shift the welded portion 5 from the lowermost bottom portion in the circumferential direction. However, in this case, there is a problem that the legs 6 and 6 cannot be positioned.

Therefore, an object of the present invention is to provide a method of manufacturing a rotary electric machine in which the legs can be easily positioned even if the welded portion of the frame is not located at the lowermost bottom portion.

[0007]

SUMMARY OF THE INVENTION A method of manufacturing a rotary electric machine according to the present invention comprises a frame formed by forming a metal plate into a substantially cylindrical shape and welding both ends thereof, and extending axially on the outer periphery of the frame. A plurality of recesses formed to be convex inward, and a pair of legs welded to the lower portion of the frame, wherein the welded portion of the frame is circumferentially displaced from the lowermost bottom portion. And at least two lower concave portions of the concave portions are provided symmetrically with respect to the lowermost bottom portion of the frame, and the pair of leg portions are provided at symmetrical positions with respect to the lowermost bottom portion of the frame. The two recesses thus formed are positioned and welded in symmetrical positions (Claim 1). In this case, it is preferable to position the welded portion of the frame between the pair of legs (claim 2).

Further, two recesses are provided symmetrically on both sides of the lower part of the frame centering on the lowermost bottom part of the frame, and a pair of leg parts is constituted by having two supporting pieces. It is advisable to weld the support pieces to the two recesses provided symmetrically (claim 3). In addition, it is preferable that the drain hole is provided at the bottom bottom of the frame and the ventilation hole is provided at a position different from the welded portion of the frame (claim 4).

[0009]

According to the first aspect of the present invention, at least the lower portion of the lower portion can be positioned even if it is impossible to position the leg portion by the welding portion because the welding portion is displaced from the lowermost bottom portion in the circumferential direction. Since the two recesses are provided symmetrically about the bottom bottom of the frame, the legs can be positioned by these recesses.

According to the second aspect of the present invention, since the welded portion is located between the pair of legs, the welded portion is hidden from the outside and cannot be seen, and the appearance is not deteriorated. According to the third aspect, when the pair of legs is attached to the frame, one support piece for each leg is provided in each of the recesses symmetrically provided on each side of the bottom bottom. Just stick them one by one.

According to the fourth aspect of the present invention, the punching process by the press which is performed when the drainage port and the ventilation hole are provided can be performed in a portion where the cross section of the frame is uniform.
It is possible to reduce the stress concentration generated in each portion as compared with the stress concentration generated when the drainage port and the ventilation hole are aligned with the welded portion.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a rotary electric machine, for example, an electric motor will be described below with reference to FIG.
FIG. 1 shows a vertical cross-sectional front view of the entire configuration of the electric motor main body. A metal plate, for example, a steel plate is formed into a cylindrical shape, and both ends of the frame 11 are joined by welding. A plurality of, in this case, eight recesses 12 extending inwardly and projecting inwardly are formed by press molding. These eight recesses 12 are provided symmetrically with respect to the lowermost bottom portion A of the frame 11, and four recesses 12 located in the lower part of the recesses 12 are provided two by two so that legs 13 described later can be attached. 2 pairs (indicated by 12a and 12b) to form the bottom bottom A
Are provided symmetrically with respect to. Where the frame 11
The bottom bottom portion A of the frame 11 is determined in relation to the welded portion 14, and specifically, the welded portion 14 is positioned so as to be displaced in the circumferential direction from the bottom bottom portion A, for example, when forming the recess 12 of the frame 11. Between the pair of recesses 12a and 12b located at the lower portion, one of them, in this case, the pair of recesses 12a on the left side.
The lowermost bottom portion A of the frame 11 is defined so as to be located adjacent to.

The stator coil 1 is provided on the inner circumference of these recesses 12.
Since the stator 16 wound with 5 is attached by press fitting, and these recesses 12 are convex inward,
An air passage 17 is formed between the stator 16 and the frame 11 and between the adjacent recesses 12. And the stator 16
The rotor 18 is inserted inwardly of the shaft, and the rotary shaft 19 having the rotor 18 mounted thereon is supported by bearing brackets (not shown) attached to both axial ends of the frame 11 via bearings.

Outside the frame 11, a pair of steel plate leg portions 13 having a U-shaped cross section for supporting the weight of the entire electric motor and for fixing the electric motor main body to an installation portion (not shown) are provided on the frame 11. The two pairs of recesses 12a and 12b located at the lower portion are fixed by welding. The leg portion 13 is composed of a mounting seat 13a fixed to the installation portion, and a pair of support posts 13b extending from the mounting seat 13a. The support posts 13b are the two pairs of recesses 12a, 12b. It is fixed by being fitted in.

The frame 11 has two recesses 12a and 12b located on the upper side of the two pairs of recesses 12a and 12b, and four recesses 12c located on the upper half of the frame 11 on the lower side. A plurality of ventilation holes 20 are provided between the two recesses 12c located on the side, and the air outside the frame 11 is taken in from the ventilation holes 20 or an intake port (not shown) to the inside. After the heat is taken from the stator 16 when flowing through the passage 17, the electric motor is cooled by being discharged to the outside of the frame from an exhaust port (not shown). Further, a drain port 21 for discharging the water to the outside of the frame 11 when water enters from the ventilation hole 20 or the like is provided in the bottom bottom portion A of the frame 11.

When the electric motor is electrically driven in this configuration, a magnetic field is generated inside the stator coil 15, and the rotor 18 rotates as the magnetic field rotates. At this time, even if a load or torque acts in the radial direction on the rotary shaft 19 and stress is generated in the frame 11, both the drainage port 21 and the ventilation hole 20 are provided at positions different from the welded portion 14. The strong stress concentration due to the drainage port 21 and the ventilation hole 20 being aligned with the welded portion 14 can be reduced, and the occurrence of cracks and the like can be prevented.

Further, when the drainage port 21 and the ventilation hole 20 are formed, punching is performed by a press in a portion of the frame 11 where the cross section is uniform, so that the accuracy of hole making increases and the workability is improved. In addition, there is no possibility that the punching die will be damaged due to excessive force.

Further, although the welded portion 14 is provided on the frame 11 so as to be displaced from the lowermost bottom portion A in the circumferential direction, it is located between the lowermost bottom portion A and the leg portion 13. It cannot be seen from the outside because it is hidden and the appearance does not deteriorate.

When the pair of legs 13 is attached to the frame 11, it is positioned near the lower part of the frame 11
One of the columns 13b of the leg 13 is fitted into the pair of recesses 12a and 12b, and fixed by welding. Therefore, the leg portion 13 is positioned around the welded portion 14 which is conventionally located at the lowermost bottom portion A, but in the present embodiment, the welded portion 14 is displaced from the lowermost bottom portion A in the circumferential direction. Even if it is located, since the column 13b of the leg 13 is fitted and fixed to the recess 12a, the positioning is further facilitated and the ease of assembly is improved.

Next, FIG. 2 shows a second embodiment of the present invention. In addition to the ventilation holes 20 formed in the first embodiment, two pairs of recesses 12 provided in the lower portion of the frame 11 are provided.
Ventilation holes 22 are provided symmetrically around the bottom bottom portion A between a and 12b, and the left one of these ventilation holes 22 is located between the welded portion 14 and the bottom bottom portion A. .
In this case, the two ventilation holes 21 also function as drainage ports,
Therefore, also in this embodiment, the same effect as that of the first embodiment can be obtained.

FIG. 3 shows a third embodiment of the present invention.
In this embodiment, in addition to the ventilation holes 20 of the first embodiment,
Two pairs of recesses 12a provided in the lower portion of the frame 11,
Four ventilation holes 23 are provided symmetrically with respect to the lowermost bottom portion A between 12b. At this time, the welded portion 24 is located on the left side of the lowermost bottom portion A among the four ventilation holes 23. It is located between the individual ventilation holes 23. In this case as well, the four ventilation holes 23 also function as drainage ports, and therefore the same effect as in the second embodiment can be obtained in this embodiment as well.

[0022]

As described above, according to the method of manufacturing a rotary electric machine of the present invention, the following effects can be obtained. According to the invention of claim 1, even if the leg cannot be positioned by the welded portion because the welded portion is displaced from the lowermost bottom portion in the circumferential direction, at least two recesses in the lower portion are provided. Are symmetrically provided about the lowermost bottom portion of the frame, the legs can be positioned by these recesses.

According to the second aspect of the invention, since the welded portion is located between the lowermost bottom portion and the leg portion, it is hidden from the outside and cannot be seen.
The appearance is not impaired. According to the invention of claim 3, when the leg portions are attached to the frame, the support pieces of the leg portions may be fixed to the recessed portions provided symmetrically with respect to each of the lowermost bottom portions. Processing becomes easy.

According to the fourth aspect of the present invention, since the punching process by the press which is performed when the drainage port and the ventilation hole are provided can be performed in a portion where the frame has a uniform cross section, the accuracy of hole making is improved. Is improved. In addition, the punching die is not damaged by excessive force. Further, since the drainage port and the ventilation hole are provided at positions different from the welded portion, the stress concentration at each portion can be reduced compared to the stress concentration caused by the matching of the drainage port and the ventilation hole with the welded portion, The generation of cracks can be prevented.

[Brief description of drawings]

FIG. 1 is an overall vertical sectional front view showing a first embodiment of the present invention.

FIG. 2 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 3 is a view corresponding to FIG. 1 showing a third embodiment of the present invention.

FIG. 4 is a view corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

Reference numeral 11 is a frame, 12 is a concave portion, 13 is a leg portion, 13b is a support (supporting piece), 14 and 24 are welded portions, 20, 22, and 23.
Is a ventilation hole, 21 is a drainage port, and A is the bottom bottom.

Claims (4)

[Claims] 1. A frame formed by forming a metal plate into a substantially cylindrical shape and welding both ends thereof, and a plurality of frames formed so as to extend in the axial direction on the outer periphery of the frame and to be convex inward. A recess and a pair of legs welded to the lower portion of the frame are provided, and the welded portion of the frame is positioned so as to be displaced in the circumferential direction from the lowermost bottom portion, and at least two recesses in the lower portion of the recess are provided. Are provided symmetrically around the bottom bottom of the frame, and the pair of legs are welded at the symmetrical positions by positioning the two recesses provided at symmetrical positions around the bottom bottom of the frame. A method of manufacturing a rotating electric machine characterized by the above. 2. The method of manufacturing a rotary electric machine according to claim 1, wherein the welded portion of the frame is located between the pair of legs. 3. A recess is provided symmetrically at the bottom of the frame, two recesses on each side of the bottom of the frame, and a pair of legs having two support pieces. The method of manufacturing a rotary electric machine according to claim 1, wherein support pieces are welded to the two recessed portions provided symmetrically. 4. The rotating electric machine according to claim 1, wherein a drain hole is provided at the bottom of the bottom of the frame, and the ventilation hole is provided at a position different from the welded portion of the frame. Production method.