JP3432876B2 - Disc spring tightening device for core transformer with gap - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer for a semiconductor power converter or a shunt reactor mainly incorporated in a cable type power transmission system for stable power supply. The present invention relates to a disc spring tightening device for a cored transformer with a gap, which is used for the above. 2. Description of the Related Art In recent years, power supplies for magnetic levitation railways have been used.
A commercial frequency three-phase alternating current is received from a power company's power system, converted to direct current by a converter, charged to a smoothing capacitor, and an arbitrary variable voltage / variable frequency power is supplied by an inverter using the smoothing capacitor as a DC power supply. The resulting semiconductor power converters are being used. A semiconductor power converter using a core transformer with a gap is used as an element constituting the converter. [0003] In a normal transformer, generally, in order to further reduce iron loss / excitation current and vibration / noise, a gap between silicon steel plate joints constituting a transformer core is reduced to reduce a magnetic resistance of an iron core magnetic circuit. I'm making it smaller. However, in a transformer for a converter used in a semiconductor power converter, an iron core provided with a gap of a magnetic insulator is employed in order to increase the magnetic resistance of the iron core to a certain level. [0004] Transformers and reactors (hereinafter referred to as "gap core transformers") employing such a core with a gap are different from ordinary transformers in that a silicon steel plate constituting the iron core is mechanically separated because the core has a gap. And a coil is wound around the outer periphery of the iron core. On the other hand, considerable magnetic attraction / repulsion occurs in the gap of this iron core,
In order to constitute a transformer, it is necessary to mechanically tighten and hold these with a predetermined tightening force that combines the magnetic attraction / repulsion force of the iron core gap and the coil tightening force. For this tightening, a tightening device using a disc spring having a considerable spring constant is used. The contents of such a cored transformer with a gap, a disc spring tightening device and an assembling jig are shown in FIGS.
This will be specifically described with reference to FIG. First, FIGS. 5A and 5B are a front sectional view and a side sectional view, respectively, of a cored transformer with a gap housed in a tank. As shown in FIG. 5, a cored transformer with a cap is housed in a tank constituted by a lower tank 18 and a tank cover 19. The transformer with a gap has a magnetic gap 1
5 and a coil 1 on the outer periphery of the core 14.
6 is wound. The iron core 14 is sandwiched between the lower clamp 13 and the upper clamp 1 in the front-rear direction, and the upper and lower clamps are connected by a crossbar 17. The tie rod 2 that connects the upper clamp 1 and the lower clamp 13 is
Both the coil spring 5 and the coil 16 are arranged together with the disc spring device 3 so that they can be evenly tightened on a plane. Next, as shown in FIG. 4, a disc spring tightening device comprising a disc spring 3, a washer 4, and nuts 5, 6 is provided on the upper end of a tie rod 2 projecting from the upper surface of the upper clamp 1, as shown in FIG. In this way, a predetermined tightening force is generated in the axial direction of the tie rod 2 to mechanically tighten and hold the gap coil 15 and the coil 16 of the iron core from the upper and lower clamps 1 and 13 via the crossbar 17. It is configured. On the other hand, as shown in FIG. 3, the disc spring tightening device in the manufactured and assembled state is mounted on the upper surface of the upper clamp 1 and is selected to obtain a predetermined tightening force.
, A washer / jack stand 11, a nut 5 for adjusting the disc spring tightening force and fixing the washer, and a locking nut 6.
It is composed of Further, a jack receiver 12 of a fastening jig and a hydraulic jack 10 are temporarily assembled above the disc spring tightening device, and a required hydraulic pressure is applied to the hydraulic jack 10 when the components of the transformer are completely mounted. It is tightened by applying pressure. The details will be described below. The hydraulic jacks 10 are symmetrically arranged around the tie rods 2 as one set, and the hydraulic pressure P1 of the hydraulic jacks 10 is applied to the shaft of the tie rods 2 via a jack receiver 12 fixed by a nut 6. In the direction
The disc spring 3 is depressed to assemble so as to generate a tightening force P between the iron core gap 15 and the coil 16 as a repulsive force. The hydraulic jack 10 and the jack receiver 1
2 is screwed down the fixing nut 5, lowered the washer / jack holder 11 after positioning, and removed the upper locking nut 6 once taken out to remove the jack receiver 12, screwed into the tie rod 2 again, firstly the washer. It is applied to the nut 5 that fixes the dual-purpose jack base 11, and this is firmly tightened to prevent the disc spring tightening device from loosening.
With the work up to this point, the assembly of the disc spring tightening device is completed,
The finished product state shown in FIG. 4 is obtained. However, in the assembly structure of the disk spring tightening jig as shown in FIG. 3, two hydraulic jacks are used for one disk spring tightening device. Not only does it take time to install and remove the tightening device, but when applying hydraulic pressure to the jack, several workers have to work on the jack so that the jack base and the jack holder are properly jacked while the jack is kept in place. It is necessary to hold the hose by hand. [0010] In the case of a larger capacity iron core transformer with a gap, the size of the jack to be used becomes large, and the disc spring tightening jig itself requires a large space. Conversely, in the case of a small transformer, the size itself is reduced, so that the space available for the disc spring tightening device is relatively reduced, and the tightening operation becomes difficult. In addition, the tie rod part remaining above the nut for preventing the disc spring from loosening is an unnecessary part after the work of tightening the disc spring has been completed. Left without cutting. On the other hand, the height of the tank cover for storing the transformer contents is determined by the height of the tie rods in most cases than by the maximum height of the contents. The height of the tank, which corresponds to the above, is a factor that increases the cost of the transformer as a whole, such as material costs including insulating oil and steel. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to reduce troublesome work in tightening a disc spring, secure work safety, and reduce the size of the transformer. Accordingly, an object of the present invention is to provide an inexpensive iron core transformer with a gap by reducing the man-hours for manufacturing the transformer, making it easy to assemble, and cheaper. SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a disc spring tightening apparatus for a core transformer with a gap, which clamps a core gap and a coil of a core transformer or a reactor with a gap with a disc spring. , A washer provided on the disc spring, and an inverted U-shaped jack table which is arranged on the upper surface of the washer in series on an extension of the center axis of the tie rod,
A hollow box-type jack receiver with a nut function mounted at an interval above the jack base and a hydraulic jack attached to the interval portion are provided, and hydraulic pressure is applied to the hydraulic jack to apply the force to the disc spring. By being compressed, the repulsive force of the disc spring is transmitted to the tie rod, and a predetermined tightening force is applied to the iron core gap and the coil. The jig for the disk spring tightening device of the present invention tightens the disk spring with one hydraulic jack placed on the extension of the center axis of the tie rod, and uses the repulsive force to force the die rod through the jack receiver. So that the jack receiver arranged at the top is pushed up by two jacks like a conventional jig for a tightening device.
The size of the jig itself can be reduced to about half. Also,
By moving the position for placing the jack upward from the side of the tie rod, the tie rod length corresponding to the jack height can be shortened. This allows the entire height of the transformer tank to be reduced. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Configuration of Embodiment] An embodiment of a jig for a disk spring tightening device according to the present invention will be described below with reference to FIG. 2A is a side view of the same view as viewed from the X direction, FIG. 2B is a side view of the same view as viewed from the Y direction, and FIG. 2C is a plan view. . The same parts as in the prior art are denoted by the same reference numerals, and redundant description will be omitted. As shown in FIG. 1, the lower end is fixed to the lower clamp (not shown in detail), and the tie rod 2 is inserted through the mounting hole of the upper clamp 1 so as to penetrate the tie rod 2. Disc spring 3 and washer 4 on top of 1
On the upper surface of the washer 4, a nut 5 for transmitting the repulsive force of the disc spring 3 to the tie rod 2 and a nut 6 for preventing loosening are overlapped and loosely screwed. Next, at the upper end thread portion of the tie rod 2,
A jack 10 can be mounted between the jack stand 9 and a hollow box-type jack receiver 7 having a nut function with a threaded lower plate portion.
At this time, the jack receiver 7 can be screwed in by hand, and it is not necessary to use a tool to tighten it firmly. Further, an inverted U-shaped jack base 9 arranged on an extension of the center axis of the tie rod 2 is placed on the upper surface of the washer 4 so as to straddle the lower plate portion of the jack receiver 7, and the hydraulic jack 10 is jacked. The disc spring is fastened by being inserted and arranged between the table 9 and the jack receiver 7 to constitute a device jig. [Effects of the Embodiment] The jig for the disc spring tightening device shown in FIG.
The hydraulic P ₁ is generated by applying hydraulic pressure to. Since the hydraulic pressure P ₁ is constrained at the upper part by the jack receiver 7 screwed and fixed to the tie rod 2, the difference [BA] of the jack stroke difference is transferred via the jack base 9 and the washer 4. Then, the disc spring 3 is pressed down to generate a repulsive force corresponding to a difference between the free length C of the disc spring before applying hydraulic pressure and the dimension D after compression. At this time, the nuts 5 and 6 are simultaneously turned and lowered to the clamp side, and lightly screwed in until they come into close contact with the washer 4. Thereafter, the hydraulic pressure applied to the jack 10 is released to remove the jack, and the jack base 9 and the jack receiver 7 are sequentially removed to complete the disc spring tightening operation. FIG. 2 shows the work completion state. The repulsive force P of the disc spring 3 compressed by the pressure P ₁ generated by this operation is transmitted to the tie rods 2, thereby as shown in FIG. 5 described above, the upper and lower from the upper clamp 1 and the lower clamp 13 The core gap 15 and the coil 16 can be tightened and held with a predetermined tightening force via the cross bar 17. As described above, according to this embodiment, only one hydraulic jack needs to be used for one place of the coned disc spring tightening device. Also, when hydraulic pressure is applied to the jack, the time required for the operator to press the hose portion of the jack by hand can be reduced by about half. Furthermore, the space occupied by the jig is reduced by downsizing the jig for the disc spring tightening device, and the tie rod portion remaining above the locking nut of the disc spring is reduced by about one jack compared to the conventional configuration. , The height of the tank corresponding to this dimension can of course be reduced. As described above, according to the present invention, the troublesome work of tightening the disk spring is reduced, the safety of the work is secured, and the size of the transformer is reduced. By holding down, it is possible to reduce the manufacturing man-hours and material costs of the transformer, thereby making it possible to reduce the cost, and to provide a more cost-effective iron core transformer with a gap.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a structural view of an embodiment of a jig for a disk spring tightening device according to the present invention, wherein FIG. 1 (a) is a side view as viewed from the X direction of FIG. 1 (b). FIG. 2B is a side view as viewed from the Y direction in FIG. 2A, and FIG. 2C is a plan view. FIG. 2 is a view showing a state in which a disk spring tightening operation is completed by the disk spring tightening device of the present invention. FIG. 3 is a view showing a conventional jig assembly for a disc spring tightening device. FIG. 4 is a view showing a state in which a conventional disc spring tightening device completes the work of tightening the spring. FIG. 5 is a schematic configuration diagram of the entire contents of a cored transformer with a gap, in which FIG. 5A is a front sectional view, and FIG. 5B is a side sectional view. [Description of Signs] 1 ... Upper clamp, 2 ... Tie rod, 3 ... Disc spring, 4 ...
Washers, 5: tightening nuts, 6: locking nuts, 7: jack receivers, 8: screws for connecting jack receivers, 9: jack stands, 10: hydraulic jacks, 11: jack stands serving as washers, 12: jack holders, 13 ... Lower clamp, 14 ...
Iron core with gap, 15 ... iron core cap, 16 ... coil,
17: crossbar, 18: lower tank, 19: tank cover.

Claims (1)

(57) [Claim 1] In a disc spring tightening device for a core transformer with a gap, wherein a core gap and a coil of a core transformer with a gap or a reactor are fastened by a disc spring, the disc spring is provided on the disc spring. A washer, an inverted U-shaped jack stand arranged in series on the upper surface of the washer on the extension of the center axis of the tie rod, and a hollow box-type jack receiver with a nut function mounted at an interval above the jack stand. And a hydraulic jack attached to the gap, applying hydraulic pressure to the hydraulic jack, compressing the disc spring by this force, transmitting the repulsive force of the disc spring to the tie rod, A disc spring tightening device for a cored transformer with a gap, wherein a predetermined tightening force is applied to a coil.