JPH06333749A - Transformer - Google Patents

Abstract

PURPOSE:To provide small size and lightweight configuration by improving cooling characteristics and further reduce a surge shift voltage to a coil by giving an electrostatic shield function in a transformer. CONSTITUTION:Unit coils 16a wound in a disc shape are stacked in axial direction in a coil 16; the coil 16 is so disposed that a heat receiving portion 10a of a loop type heat pipe 10 turned and formed to a coil shape is tightly contacted to the winding surface of an unit coil 16a; and a heat radiating portion 10b is arranged in oil outside the coil 16. This loop type heat pipe 10 is grounded at one point to provide an electrostatic shield function.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer for cooling the heat generated in the contents of a transformer, which is composed of an iron core, a coil, an insulator, etc., stored in a main body tank, using a loop heat pipe. is there.

[0002]

2. Description of the Related Art For example, a vehicle transformer is strongly required to be small and lightweight because of limitations in fitting. For this reason, a copper machine is designed to reduce the weight of the iron core, which accounts for a large proportion of the weight of the transformer, as compared with a general transformer.

However, since the copper loss is increased and the heat generation amount of the coil is increased by using the copper machine, the cooling structure of the coil becomes important. In the alternating coil arrangement structure in the vehicle transformer, disk-shaped unit coils are stacked in the axial direction, and an oil passage also serving as insulation is provided between the unit coils to circulate the insulating oil. Since the coil is generally placed horizontally, cooling by natural convection cannot be expected to have a sufficient cooling effect. Therefore, a forced oil circulation system using an oil pump is adopted.

FIG. 4 shows a schematic structure of a vehicle transformer. 1
Is a main body tank containing the contents of a transformer made of an iron core, a coil, an insulator, etc. The main body tank 1 is connected with an oil cooler 4 via a pipe 2 and an oil pump 3. The heat generated in the coil is transferred to the oil existing in the oil passage between the unit coils forming the coil, and the oil is further circulated by the oil pump 3 and flows into the oil cooler 4 where it is released to the outside. It As the oil cooler 4, a forced air cooling system with a blower 5 is generally used. The oil cooled by the oil cooler 4 is sent again into the main body tank 1 through the oil pipe 2. The body tank 1 uses a form-fit type tank structure in order to reduce the amount of oil as much as possible in order to make it compact and lightweight. Fig. 5 shows the structure of the contents of the transformer housed in the form-fitting main body tank 1. The coil 6 is configured by laminating unit coils 6a wound in a rectangular plate shape in a multi-axis direction with a plate insulator 6b interposed therebetween. A spacer 6c is attached to the flat plate insulator 6b to form an oil passage 7 between the unit coils 6a. An iron core 8 is arranged so as to interlink with the coil 6, and an insulator 6d is inserted between the iron core 8 and the coil 6 and between the coil 6 and the main body tank 1.

[0005]

By the way, in the vehicle transformer, it is necessary to provide an oil passage between the unit coils 6a in order to allow the insulating oil 9 to flow evenly to each part of the coil 6. The dimension between the unit coils 6a is determined by cooling and insulation, but in the case of a low voltage coil, the unit coil 6a
Due to the low voltage across, the cooling determines the dimensions between the unit coils.

Since a mechanical force is generated between the unit coils 6a during a short circuit, a spacer 6c for supporting the unit coils 6a while ensuring the flow of the insulating oil 9 must be provided. However, provision of the spacer 6c reduces the cooling area of the unit coil 6a, and in order to keep the temperature of the unit coil 6a at a predetermined value, the conductor size of the coil is increased to reduce the current density and the generated loss. Need to be reduced. Increasing the size of the coil conductor increases not only the weight of the coil 6 but also the size and weight of the iron core 8 and the main body tank 1 surrounding the coil 6.

Further, in the case of the rectangular coil, the stagnation occurs in the oil flow in the inner part of the short side of the coil oil outlet side due to the relationship with the iron core leg, so that the coil temperature of this part becomes the highest and the temperature design of the transformer is made. Will be determined in this part. On the other hand, since the other parts of the coil are lower than the predetermined temperature, the coil structure is wasteful.

Further, in order to cool the coil 6, it is necessary to secure a predetermined value for the flow velocity of the oil passage between the unit coils 6a,
Therefore, although the oil pump 3 is provided, there is a problem that the flow rate of the oil pump 3 increases when the number of laminated unit coils 6a increases.

Further, when the surge voltage enters the high voltage coil, the surge voltage is transferred to the low voltage coil, and depending on the case, the insulation of the low voltage coil or a device connected to the low voltage coil is threatened. In this case, an electrostatic shield plate may be inserted between the high-voltage coil and the low-voltage coil in order to reduce the surge transfer voltage to the low-voltage coil, but this causes a problem of increasing the size.

The present invention has been made to solve the above problems, and its purpose is to improve cooling characteristics and to make it compact and lightweight, and also to provide surge shielding voltage to the coil by providing an electrostatic shield function. It is to provide a transformer that can be reduced.

[0011]

In order to achieve the above object, the present invention provides a coil formed by axially stacking unit coils wound in a disk shape, and an iron core arranged so as to interlink with the coil. In the transformer, which is made by inserting the contents of the transformer into the main body tank and filling it with insulating oil, the heat receiving part of the loop heat pipe is wound to form a coil, and this coiled heat receiving part is used as a unit coil. The heat radiation part of the loop type heat pipe is arranged in oil outside the coil while the coil is closely placed on the winding surface of the coil via an insulator, and one point of this loop type heat pipe is grounded. And

[0012]

According to the transformer of the present invention, the heat generated in the coil conductor can be evenly extracted to the outside of the coil by cooling the coil with the loop heat pipe. By grounding, it is possible to have the function of an electrostatic shield.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a unit coil 1 wound in a disc shape
A coil 16 is formed by stacking 6a in the axial direction, and an iron core 8 is arranged so as to interlink with the coil 16 to form the transformer contents. The contents of this transformer are inserted into the main body tank 11. The main body tank 11 is filled with insulating oil 9,
Although not shown, this insulating oil 9 is forcedly circulated by an oil pump and forcedly cooled by an oil cooler with a blower.

Here, the unit coil 1 that constitutes the coil 16
A loop heat pipe 10 having an electrostatic shield function is provided on the winding surface of 6a. As shown in FIGS. 2 (a) and 2 (b), the loop heat pipe 10 has a plurality of loop thin heat pipes each having a check valve arranged side by side and integrally formed, and one end of the heat receiving portion 10a has a rectangular plate shape. And the other end of the heat radiation part 10b is arranged outside the heat receiving part 10a. The heat receiving portion 10a of the loop heat pipe 10 has a winding structure that is folded back in the middle so that one turn is not formed with respect to the iron core leg.
As shown in FIG. 3, the loop heat pipe 10 has a heat receiving portion 10a wound in a rectangular plate shape and closely attached to a winding surface of the unit coil 16a via an insulating paper 12 arranged on one surface thereof. . A plurality of unit coils having such a loop heat pipe 10 are combined with a single unit coil or a required number of unit coils to form a low-voltage secondary coil. The heat receiving portion 10a of the loop heat pipe 10 is connected to the main body tank 11 via the lead wire 13 at one place, whereby the loop heat pipe 10 becomes a ground potential and has an electrostatic shield function. The unit coil sandwiched by the loop heat pipe 10 is a low-voltage secondary coil, and the alternate coil arrangement is inserted outside the high-voltage primary coil or between the high-voltage primary coils. The heat radiating portion 10b of the loop heat pipe 10 is drawn out of the coil and placed in oil.

In this way, the heat generated by the coil 16 is transferred to the heat receiving portion 10a of the loop-shaped heat pipe 10 adjacent to the heat receiving portion 10a.
Can be drawn out from the heat dissipation portion 10b. Since the heat receiving portion 10b of the loop heat pipe 10 is formed in the shape of a rectangular plate having the same shape as the coil 16, the heat generated by the coil 16 can be uniformly removed through the working fluid. This makes coil 1
The occurrence of local overheating in 6 is eliminated. Since the heat transfer in the loop heat pipe 10 is extremely fast, there is no delay in heat dissipation even under the use condition of the transformer such as repeated overload in a short time, and a transformer strong against variable load can be obtained.

Further, although the thermal characteristics are restricted by the local temperature which is the highest temperature, since the temperature of each part of the coil 16 can be made uniform, an economical coil structure can be realized. Furthermore, the loop-shaped heat pipe 10 is closely attached to the low-voltage coil,
Moreover, since one location is grounded and has an electrostatic shield function, the electrostatic capacitance to ground of the low voltage coil is increased, and the surge transfer voltage from the high voltage coil to the low voltage coil is reduced. In addition, since the unit coils 16a including the loop heat pipe 10 can be configured as an integral flat plate,
It also has the effect of significantly improving the proof stress against short-circuit mechanical force.

[0017]

As described above, according to the transformer of the present invention, the heat receiving portion of the loop heat pipe is wound to form a coil shape, and the coil heat receiving portion is the winding surface of the unit coil. While closely arranging through the insulator, the heat dissipation part of the loop type heat pipe is arranged in oil outside the coil, and one point of this loop type heat pipe is grounded to have an electrostatic shield function. By doing so, the cooling characteristics are improved, and the surge transfer voltage to the coil can be reduced by the electrostatic shield function, so that there is an effect that the configuration can be made small and lightweight.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of a transformer according to the present invention.

2A and 2B are configuration diagrams of a loop heat pipe used in an embodiment of the present invention, FIG. 2A being a plan view and FIG. 2B being a side view.

3 is a front view showing a coil to which the loop heat pipe of FIG. 2 is attached.

FIG. 4 is a schematic configuration diagram showing a general configuration of a vehicle transformer.

FIG. 5 is a cross-sectional view showing the main part of the conventional transformer contents.

[Explanation of symbols]

8 is an iron core, 9 is insulating oil, 10 is a loop type heat pipe,
10a is a heat receiving portion, 10b is a heat radiating portion, 11 is a main body tank,
Reference numeral 16 is a coil, and 16a is a unit coil.

Claims (1)

[Claims] 1. A transformer coil comprising a coil formed by stacking unit coils wound in a disk shape in the axial direction and an iron core arranged so as to interlink with the coil is inserted into a main body tank, and insulating oil is applied. In a transformer filled with, the heat receiving part of the loop heat pipe is wound to form a coil, and the coiled heat receiving part is closely arranged on the winding surface of the unit coil via an insulator. On the other hand, the transformer is characterized in that the heat radiation portion of the loop heat pipe is arranged in oil outside the coil, and one point of the loop heat pipe is grounded.