JPH03147307A - Punching for iron core - Google Patents

Abstract

PURPOSE:To prevent a dislocation and a deformation at a bonding part of leg punchings and yoke punchings and to offer punchings for iron core use whose reliability is high by a method wherein slits are formed intermittently in nearly parallel with a lengthwise direction in punchings constituting both surface parts in a laminate direction of the punchings for iron core use. CONSTITUTION:Slender and rectangular slits 11 are formed intermittently in nearly parallel with a lengthwise direction in leng punchings 10 to be used within a thickness range of several mm to several tens of mm on both surface parts of a laminate direction. The leg punchings 10 are combined; two punchings to several punchings are used as one unit; they are displaced to one end side of their lengthwise direction and the punchings in a next unit are displaced to the other end side. While this operation is repeated alternately, the punchings are laminated. At a cross section, the punchings 10 where the slits have been formed are arranged and installed in a part where leakage magnetic fluxes from a coil exist in large quantities and whose width is minimum; leg punchings 13 where slits are not formed are arranged and installed in other parts. After the leg iron cores have been laminated, a lower-part yoke 3 is bonded so as to be brought face to face with an end part of the unit punchings of legs; a bonded part 14a is formed.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a blank for an iron core constituting a stationary induction device such as a transformer or a reactor.

(Prior Art) Generally, the iron core of a transformer or accelerator is made by cutting a thin electromagnetic steel strip of about 0.35 mm in various widths into a predetermined shape (hereinafter referred to as punching). Laminated many sheets of
The cross section is configured to be approximately circular.

In such an iron core, a large amount of leakage magnetic flux from the coil enters the leg iron core around which the coil is wound.

In particular, the minimum-width punched plate placed on the outermost side of the core cross section receives the leakage magnetic flux in a concentrated manner on its surface. As a result, eddy currents are generated in proportion to the amount of leakage magnetic flux and the width of the blank, which not only overheats the core and causes energy loss, but also sometimes causes the blank to melt and generate harmful substances. There is a risk of lowering the dielectric strength and causing a major accident. Furthermore, vibration and noise may be amplified and the performance of the equipment may be significantly degraded. This tendency becomes more pronounced as the device becomes larger and as the magnetic flux density becomes higher. Therefore, the size of the eddy current can be reduced by dividing the punched plate, which is several millimeters to several millimeters thick from the outside in the lamination direction of the iron core, into several pieces in the width direction. It is common practice to suppress the energy loss, vibration, and noise mentioned above, and to prevent accidents.

FIG. 6 shows the configuration of conventional punching, and FIG. 7 shows the layout of the punching of a three-phase tripod core in which the core is constructed using the same punching. That is, as shown in FIG. 6, the punched plate 1 near the minimum width arranged outside the core cross section is configured with a divided portion 2 provided at an arbitrary position in the width direction. Then, shift one set or several sets of such punched boards as a unit in one direction in the longitudinal direction of the punched boards by an arbitrary dimension, and for the next unit punched board, shift it in the other direction while cutting around the minimum width of the leg core. Configure. In addition, in other punchings other than those around the minimum width, one set to several sets are stacked as one unit while being staggered in the same manner to form a leg core having a substantially circular cross-sectional shape. After each leg core is assembled in this way, the lower yoke punched board 3, which has approximately the same number of punched sheets as the leg core as one unit, is joined so as to match the end of the unit punched board of the leg, A joint portion 4a is formed. After inserting the coil into each leg core, one part of the yoke punched plate 5 is joined from the negative part so as to be brought into contact with the end of the unit punched plate of the leg, thereby forming a joint part 4b.

(Problems to be Solved by the Invention) However, in the conventional core punching configured as described above, there were problems to be solved as described below.

That is, the upper and lower yoke punching plates 3 and 5 are cut into leg punching plates 1 for each unit number.
When joining, the leg punching boards are separated one by one in the width direction, so lift it from one side, insert one end of the yoke, then lift the next divided leg punching board,
After inserting the yoke a little and repeating this action for the number of divisions to complete one side of the joint, insert the yoke in the same way, and then the other leg in the same way.

As described above, the assembly workability is very poor and requires a lot of labor and time.Also, even if one end is inserted, the lower yoke punching plate 3 is difficult to insert when inserting the center part and the other end. As shown in Fig. 8, the assembly work must be performed while tilting in the longitudinal direction, and the leg punching plate 1a placed on the core window side may come off at the joint 4a inserted earlier. Ta. Such a punched joint on the window side of the core is difficult to see from the side of the worker who is inserting the yoke, so there were many cases where the work was continued with the two parts unjoined. In addition, even if the two do not come apart, the leg punching board and yoke punching board are not in a tight contact state, so many gaps occur at the joint, and when the equipment is operated,
This would increase iron loss, excitation current, and amplify vibration and noise. Furthermore, when the core is erected, in addition to its own weight, all the loads from the coils and other loads are applied to the core, but the leg punching near the minimum width is divided in the width direction, so its rigidity is weak, and it may shift in the width direction. Otherwise, it swells in the stacking direction, causing distortion and deteriorating the characteristics of the device.

The present invention was proposed in order to eliminate the above-mentioned drawbacks, and its purpose is to improve the workability of assembling the iron core, prevent displacement and deformation of the joint between the leg punching plate and the yoke punching plate, and provide reliability. The objective is to provide a punched plate for iron cores with high properties.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides that, in punching for a core constituting the core of a stationary induction device, the punching constituting both surface portions in the lamination direction is approximately parallel to the longitudinal direction of the punching. It is characterized in that slits are formed intermittently in parallel.

(Function) According to the core punching of the present invention, it is possible to suppress eddy currents generated by leakage magnetic flux incident from the coil, and since the punching is not divided, the yoke punching can be used for leg cores. When inserting the yoke into the leg punching board to form a joint, there are few parts to widen the leg punching board, and joining can be completed by simply inserting a part of the yoke punching board into the leg punching board and sliding it. Further, when joining the yoke blank to another leg core, the already joined blank does not come off from the joint. Furthermore, the leg punching board with the slits has high rigidity because it is not divided in the width direction, so even if it receives coils or other loads after the core is erected, it will not shift in the width direction or expand in the stacking direction. It does not cause distortion or the like.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIGS. 1 to 5. Incidentally, the same members as those of the conventional type shown in FIGS. 6 to 8 are given the same reference numerals (i=1), and their explanations will be omitted.

In this embodiment, as shown in Fig. 1, the leg punching plates 1, 0 used in the thickness range of several millimeters to several tens of millimeters on both surface portions in the laminating direction are Thin rectangular slits 11 are formed intermittently. In addition,
The slits may be formed as thin, approximately elliptical slits 12 as shown in FIGS. 2 and 3, or may be formed in multiple rows in the width direction. In addition, all of these slits are formed by plastic processing using a press mold, etc., and the length Ω1 and width g2 of these slits are
are formed to have approximately the same length.

Furthermore, the length a between the slits formed intermittently in the longitudinal direction, the length b between the slits formed in multiple rows, and the length C from the width direction end of the punched plate to the slit are also approximately the same. is formed. In addition, as shown in FIGS. 2 and 3, when the slit 12 extends over the longitudinal end of the punched board, one of the slits I.12a is placed inside the punched board,
The slit 12b at the other end is configured so that a part thereof is located inside the blank. In this case, in the case where many rows of slits are formed in the width direction of the punched board, the slits are arranged so as to be alternately shifted in order such that the -th row of slits is placed on the left end, and the next row is placed on the right end.

In the core punching of this embodiment having such a configuration, the core is configured as described below. That is, the second
The leg punching boards 10 shown in the figures and FIG. is shifted to the other end side, and the layers are stacked while repeating this process alternately. The cross section of the leg core laminated in this way is as shown in Figure 5.
A punched plate 10 with a slit is disposed near the minimum width f-j where there is a large amount of leakage magnetic flux from the coil, and a leg punched plate 13 without a slit is disposed in other parts. There is. - After completing the lamination of the leg core as described in , the lower yoke 3 is joined as one unit with approximately the same number of leg punches as the lower yoke 3 so as to match the ends of the leg unit punches,
A joint 1.4a is formed. Further, after inserting the coil into each leg core, the upper yoke blank 5 is inserted from above in the same manner.

In addition, the slit 11 of the leg punching board. ], 2, if one or two types of pressure tools such as molds are prepared, the shape of the punched plate, = J
It is possible to respond appropriately to changes in laws and regulations, and processing is also easy. Furthermore, the slits formed in the punched board have the function of suppressing eddy currents generated by leakage magnetic flux incident on the punched board to a predetermined magnitude. Furthermore, in the process of assembling the iron core, the yoke punching plates 3 and 5 are replaced with the leg punching plate 1.
When inserting into the longitudinal end of 0 to form the joint 14, the leg punching board is formed as one piece and is not divided, so
There is no need to expand each punch. Further, when inserting the yoke blank, there is no possibility that the joint with the leg at the other end, which has already been joined, will come off or a gap will be created at the joint. Furthermore, since the leg punching board is not divided in the width direction, it has high rigidity, so even if it receives a coil or other load after the core is erected, it will not shift in the width direction or expand in the stacking direction, causing distortion. Nor.

In this way, according to this embodiment, it is possible to suppress the eddy current generated by the leakage magnetic flux incident from the coil, and since the punched plate is not divided, the yoke punched plate can be inserted into the leg core and joined. When assembling the parts, there are few parts to widen the leg punching board, and joining can be completed by simply inserting a part of the yoke punching board into the leg punching board and sliding it. Further, when joining the yoke blank to another leg core, since the blank is not divided, the joined blank will not come off from the joint. Furthermore, the leg punching board with the slits is not divided in the width direction, so it has high rigidity, so even if it receives coils or other loads after the core is erected, it will not shift in the width direction.
It does not expand in the stacking direction and cause distortion.

[Effects of the Invention] As described above, according to the present invention, slits are intermittently formed substantially parallel to the longitudinal direction of the blanks forming both surface portions in the lamination direction of the core blanks. By a simple means, it is possible to provide a highly reliable iron core punch that improves the workability of assembling the core and prevents displacement and deformation of the joint portion between the leg punch and the yoke punch.

[Brief explanation of the drawing]

1 to 3 are plan views showing one embodiment of the leg punching board used for core punching of the present invention, and FIG. Figure 5 is a cross-sectional view of the leg core shown in Figure 4;
Fig. 6 is a plan view showing a state in which a conventional leg punching plate is divided in the width direction, and Fig. 7 is an arrangement diagram of the punching plates when a three-phase tripod core is constructed using the punching plates shown in Fig. 6. , FIG. 8 is a plan view showing the state in which the lower yoke punching board is joined to the leg punching board. 1... Leg punching, 2... Divided portion, 3... Lower yoke punching, 4a, 4b... Joint portion, 5...-L section yoke punching, 10... Leg punching Plate, 11...Slit, 1
2... Substantially oval slit, 13... Leg punched plate in which no slit is formed, 14a, 14b... Joint portion.

Claims (1)

[Scope of Claims] A punched core for forming the core of a stationary induction device is characterized in that slits are formed intermittently substantially parallel to the longitudinal direction of the punched sheet forming both surface portions in the lamination direction. Cuttings for iron cores.