JPS6214087B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of magnetic circuits made of laminated steel plates, and particularly to improvements in the production method of producing iron cores by welding.

In order to reduce eddy current, etc., when thin steel plates with insulation coating on their surfaces are laminated and bonded together by arc welding to form an iron core, for example, if the thin steel plates are E-shaped, Figure 1 As shown, protrusions 2 for arc welding were formed at the welding locations of the thin steel plates 1 for each steel plate, and the protrusions at the same position when stacked were welded together. However, in this method, as shown in FIGS. 2 and 3, the weld bead 3 is continuous in the thickness direction of the iron core 4 and forms a linear weld 5, which has a large thermal effect on the surroundings, and the magnetic circuit The efficiency of the magnetic circuit decreases due to an increase in magnetic resistance, hysteresis, and iron loss due to eddy current. In addition, from the viewpoint of manufacturing efficiency, it is necessary to set an appropriate welding speed to form a continuous weld bead, and it has been difficult to shorten the working time.

This invention was made based on the above circumstances,
A high-energy beam is irradiated at each overlap of the laminated thin steel plates to weld them together, greatly improving manufacturing efficiency.

The present invention will be described below based on drawings showing embodiments.

Figure 4 shows an example of a device for carrying out the present invention, in which a workpiece to be welded, that is, an iron core, is fixedly installed, and the irradiation side of a high-energy beam is driven in a pulsed manner to perform welding, and the beam oscillates. an optical system that focuses the beam oscillated from this beam oscillation unit on a welding position, a scanning system that scans this optical system to a predetermined position, and a control system that controls this scanning system and the beam oscillation unit. It is configured. That is, it has a drive table 11 that is horizontally slidable on a fixed pedestal 10, and this drive table 11
is adapted to reciprocate in the direction of arrow A in the figure by a pulse motor 12 with one side protruding. A holding cylinder 13 is vertically fixed to one end of the drive table 11. This holding cylinder 1
Inside 3, there is a reflector 14 with its reflective surface facing downward, and 45
The condenser lens 15 and the protective glass 16 are installed in this order. Furthermore, an opening 17 is formed on the side surface of the holding cylinder 13 to allow light to enter the reflecting surface. On the other hand, a pulse laser oscillator 20 that oscillates a laser beam 19 with a pulse width of several milliseconds at a predetermined timing using a controlled power source 18 is installed at a position where the beam 19 is incident on the reflecting surface. A control signal generator 21 is connected to the control power source 18 and generates a pulse signal at regular pitches. Further, this signal generating section 21 also sends the above-mentioned pulse signal to a drive control section 22 connected to the pulse motor 12. A starting signal generator 23 is connected to the control signal generator 21 to output the pulse signals in these two directions. Further, a pair of limit switches 24a and 24b are installed near the top surface of the drive table 11, and when they come into contact with an attachment 25 attached to the top surface of the drive table 11, they detect the predetermined start and stop positions of the drive table 11. The signals are respectively given to the control signal generating section 21.

Next, as shown in FIG. 5, a welding process using the above apparatus for a steel plate 26 punched into an E shape will be explained using FIG. 4.

First, a certain number of steel plates 26 are stacked one on top of the other...
The block 27 is the first overlapping seam 2.
It is installed at a position where the laser beam 19 is focused at 8a. Next, when a starting signal is given to the control signal generating section 21 by the starting signal generating section 23, a pulse signal is generated from the control signal generating section 21 at each overlap pitch of the steel plates 26. is input to the laser oscillation control power supply 18, and the other of the above signals is input to the drive control section 22, respectively. Therefore, the laser beam 19 from the pulse laser oscillator 20 emits pulses in synchronization with the stop position of the drive table 11, which is step-driven to the pitch width of the overlapping mesh by the pulse motor 12 controlled by the drive control unit 22. The light is irradiated onto the block 27 via the reflecting mirror 14 and the condensing lens 15. This irradiation is carried out one after another, and welds 29 are formed regularly from the first overlap 28a of the block 27 to the final overlap 28n in this direction, and an iron core can be obtained. . Note that after the final overlapping seam 28n is completed, the driving table 11
The attachment 25 attached to the drive table 11 contacts the limit switch 24b, and this action stops the oscillation of the laser beam 19.
is moved backward to return to a predetermined position, and is stopped at the predetermined position by the limit switch 24b, in preparation for welding the next block.

In this way, each steel plate 26 constituting the iron core is scanned in a pulsed manner in the thickness direction.
6... Since the pulse beam is irradiated in accordance with the pitch of the mutual overlap, the welded part 29... that is formed is as shown in Fig. 6, and the weld penetration part is similar to the conventional continuous one shown in Fig. 3. Unlike the melted part, the required minimum amount is used, and the irradiation pulse energy is effectively used. Especially when the pulse width of pulsed laser is 1~
In the 20mS area, the heat effect on the surroundings is reduced,
Therefore, it is extremely advantageous for manufacturing iron cores using relatively thin steel plates that are easily deformed by heat, and magnetic circuits can be manufactured with highly accurate dimensions. Therefore, when applied to the stator core of a motor, the gap between the rotor and the rotor can be reduced, helping to improve the efficiency of the motor. In addition, since only the overlap seams are welded, there is little deterioration of magnetic properties compared to the welding strength, so the cross-sectional area of the magnetic circuit can be used effectively, so the magnetic circuit can be made smaller.
The required magnetic circuit performance can be obtained with a small amount of magnetic material, contributing to energy savings such as material savings and power equipment efficiency. Furthermore, since there are no welded parts on the surfaces of both ends of the laminated steel plates, the flattening process that was required in the past is no longer necessary.

In the above embodiment, a laser beam is irradiated from the end of a block body made by stacking a predetermined number of steel plates at the overlapped pitches while scanning, but it is possible to The eye may be detected and illuminated by methods such as photoelectric, magnetic, or electrostatic.

Furthermore, instead of stacking a predetermined number of steel plates and then irradiating them, immediately after the so-called knock-out process, in which the steel plates are punched out one by one using a press process, welding is carried out at the overlap seam, and a predetermined number of high-energy beams are applied while counting the number of welds. It is also possible to produce blocks, ie cores, by irradiating in pulses. In addition, instead of simply limiting this to one block, after the first block is completed, the high-energy beam irradiation is interrupted, and the steel plate to be punched is placed directly on top of this block to create a non-welding space. , the first
By welding the overlapping seams of each steel plate to each other in the same manner as in the case of the above block, the next block can be formed in succession to the first block. If you repeat this process, the third and fourth
Blocks can be formed sequentially and sequentially. Therefore, in addition to obtaining the same effects as the embodiment described with reference to the drawings, the manufacturing process can be simplified and efficiency can be greatly improved.

[Brief explanation of the drawing]

Fig. 1 is a plan view of core steel plates to be joined by conventional welding, Fig. 2 is a side view showing the welding state by the conventional welding method, and Fig. 3 is a welded part formed by the above-mentioned conventional welding method. 4 is a block diagram showing an embodiment of the present invention, FIG. 5 is a plan view of a steel plate for an iron core in the above embodiment, and FIG. 6 is a sectional view of a welded portion in the above embodiment. 11... Drive table, 12... Pulse motor, 14... Reflector, 15... Condensing lens, 18
... Control power supply, 19 ... Laser beam, 20 ...
Pulse laser oscillator, 21... control signal generation section,
22... Drive control section, 23... Start signal generation section,
26... Steel plate, 27... Block, 28a, 28
n... Overlapping seam, 29... Welding part.

Claims (1)

[Claims] 1. In a method for manufacturing an iron core formed by laminating a large number of steel plates of a predetermined shape, a spot of a laser beam is irradiated onto each overlapping portion of the steel plates, and the steel plates are welded together by discontinuous welding of each overlapping portion using these spots. A method for manufacturing an iron core characterized by combining.