JP2000252101A - Water-cooled resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-cooled resistor which can eliminate the need for strict management to increase the dimensional accuracy of the resisting material, can sufficiently accommodate variations in the entire length of the resistor and changes in the dimensions due to thermal expansion, can reliably hold watertightness between an insulating cooling pipe and a cooling pipe holder, and can increase safety with respect to water leakage. SOLUTION: In a water-cooled resistor 1, wherein both ends of an insulating cooling pipe 2 are watertightly fixed by cooling pipe holders 3, one of the holder 3 is provided with water supply port 5 and water discharge port 6, a resistor 7 is provided within the cooling pipe 2, and cooling water is circulated through the interior of the cooling pipe 2 to cool the resistor 7. A resilient member 9, preferably a compression coil spring, is disposed between one end of the resistor 7 and the pipe holder 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-cooled resistor used in a large power circuit, for example, a water-cooled resistor used for protecting an electronic control inverter (inverting device).

[0002]

2. Description of the Related Art In a high-power circuit, a water-cooled resistor for forced cooling is usually used to absorb load energy when a large power is applied. As the process progresses, space-saving and high-performance resistors are increasingly demanded.

Conventionally, various proposals have been made on the basis of such demands. In order to satisfy the demands, the inventor of the present invention has attempted to satisfy the demands as shown in FIG. The cooling pipe holders 3 and 4 are fixed in a watertight manner with stat bolts 10, one of the cooling pipe holders 4 is provided with a water supply port 5 and a drain port 6, and a resistor 7 is disposed inside the insulating cooling pipe 2. A water-cooled resistor 13 in which cooling water is circulated outside the insulating cooling pipe 2 and inside the insulating cooling pipe 2 through the cooling water passage 8 to cool the resistor with water is proposed. A patent application was filed as Hei 10-226726.

This water-cooled resistor has a high cooling efficiency, can effectively absorb load energy when a large power is loaded, can be suitably used as a water-cooled resistor for a high-power circuit, and saves energy. Although it is possible to increase the space, it is possible to increase the resistance of the water-cooled resistor with this structure due to variations in the length of the resistor placed in the insulating cooling pipe and thermal expansion due to Joule heat when absorbing the load. Due to the dimensional changes that occur in the body, voids have been created between the insulating cooling pipe and the cooling pipe retainer, and water leakage has been experienced.

In order to prevent water leakage and absorb a high load, it is necessary to reduce variations in the entire length of the resistor, and to absorb the thermal expansion of the resistor caused when the load is absorbed, thereby insulating the cooling pipe and the cooling pipe. It is important to maintain water tightness with the cage.

In order to improve the dimensional accuracy of the entire length of the resistor,
Although there is a method of strictly setting the inspection standard after cutting the resistor, there is a problem that the production yield of the resistor is reduced and the cost is increased. In order to absorb the thermal expansion of the resistor,
Although a method of inserting the elastic resin 11 between the insulating cooling pipe and the cooling pipe holder as shown in FIG. 2 has been proposed, in this method, the degree of absorption of the deformation amount of the resistor is very large. Therefore, variations in the overall length of the resistor and dimensional changes due to thermal expansion cannot be sufficiently absorbed, and water leakage may still occur.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-described problem of water leakage of a water-cooled resistor, the present invention has been repeated experiments and studies from various viewpoints on a structure for absorbing thermal expansion of a resistor. The purpose was to be able to sufficiently absorb the dimensional change due to the variation in the overall length of the resistor and thermal expansion without the need for strict control to increase the dimensional accuracy of the resistor, It is an object of the present invention to provide a water-cooled resistor having an improved structure capable of reliably maintaining water tightness between an insulating cooling pipe and a cooling pipe holder.

[0008]

According to a first aspect of the present invention, there is provided a water-cooled resistor in which both ends of an insulating cooling pipe are watertightly fixed by a cooling pipe holder. The cooling pipe holder is provided with a water supply port and a drain port, a resistor is disposed inside the insulating cooling pipe, and cooling water is circulated inside the insulating cooling pipe to water-cool the resistor. In a water-cooled resistor, an elastic body is interposed between an end of the resistor and the cooling pipe holder.

According to a second aspect of the present invention, there is provided a water-cooled resistor according to the first aspect, wherein the elastic body is interposed between the resistor and a cooling pipe holder provided with a water supply port and a drain port. The water-cooled resistor according to claim 3 is characterized in that:
In the second aspect, the elastic body is a compression coil spring.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, as shown in FIG. 1, for example, cooling tube holders 3, 4 are sandwiched between both ends of an insulating cooling tube 2 with stud bolts 10, and a resin is provided as necessary. The cooling pipe holder 12 is provided with a water supply port 5 and a water discharge port 6, and a resistor 7 is provided inside the insulating cooling pipe 2. And circulates cooling water inside the insulating cooling pipe 2 through the outside of the insulating cooling pipe 7 and through the cooling water passage 8.
In a water-cooled resistor in which the resistor 7 is water-cooled,
An elastic body 9 is interposed between the end of the resistor and the cooling pipe holder.

The elastic body 9 can be interposed between both ends of the resistor 7 and the cooling pipe holders 3 and 4, but practically, the elastic body 9 is formed by connecting the resistor 7 and the water supply port 5 to each other. It is preferable to interpose the cooling pipe holder 4 provided with the drain port 6.
According to this structure, the elastic body 9 is close to the water supply port 5, and the cooling water supplied from the water supply port 5 first cools the elastic body 9. The elastic performance is kept constant and a constant absorption effect can always be maintained.

As the elastic body 9, a compression coil spring made of metal, a bellows-shaped metal tube which can be extended and contracted in the length direction, or the like can be used. However, in practice, it is most preferable to use a compression coil spring. In addition, since the elastic body 9 is in contact with the resistor 7 and is used in water, it is preferable that the elastic body 9 be subjected to a corrosion resistance treatment excellent in electric conductivity.

[0013] By interposing the compression coil spring, the variation in the entire length of the resistor, which is usually about ± 0.5 mm, and the thermal expansion of the resistor due to Joule heat when absorbing the load are all absorbed, the insulating cooling pipe is provided. 2 and cooling pipe holder 2,
No air gap is formed between the first and second air conditioners 3, and the watertight state is maintained, so that the occurrence of water leakage can be reliably prevented.

[0014]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples, and the effects thereof will be demonstrated based on them. It should be noted that these examples are for describing a preferred embodiment of the present invention, and the present invention is not limited thereto.

Examples 1 to 6 As a resistor, a metal oxide was added to an aluminosilicate,
After mixing and kneading, the mixture was extruded into a cylindrical shape by an extruder, and then sufficiently dried.
A ceramic resistor obtained by firing at a temperature of ℃ is used, and a compression coil spring is used as an elastic body. The water-cooled resistor shown in FIG. The variation in the overall length of the used parts and the load that can be absorbed were investigated based on the presence or absence of the load. Table 1 shows the results. The ceramic resistor used was
It has a resistance value of several Ω to several hundred Ω, and can absorb large power by water cooling.

[0016]

[Table 1] << Table Note >> Water Leakage Occurrence ○: No Water Leakage

As can be seen from Table 1, in the water type resistor according to the present invention (Examples 1 to 6), an insulating cooling pipe 0.5 mm shorter than the reference size and a 0.5 m shorter than the reference size.
Even if the load at the time of energization is 6 kW with a combination of m long resistors, the variation in the length of the parts used and the dimensional change due to the thermal expansion of the resistors are absorbed by the compression coil spring,
Water tightness between the insulating cooling pipe and the cooling pipe holder was maintained, and no water leakage occurred.

Comparative Examples 1 to 6 A water-cooled resistor shown in FIG. 2 in which the same ceramic resistor as in Example 1 was incorporated, and an elastic resin 12 was interposed between an insulating cooling pipe and a cooling pipe holder. In the same manner as in the example, the variation in the entire length of the used parts and the load that can be absorbed were examined based on whether or not water leakage occurred. Table 2 shows the results.

[0019]

[Table 2] << Table Note >> Water leakage ○: No water leakage ×: Water leakage

As shown in Table 2, 0.3 m from the standard size
When an insulating cooling pipe shorter by m and a resistor 0.3 mm longer than the reference dimension are combined (Comparative Example 4), the insulating cooling pipe shorter by 0.4 mm than the reference dimension and 0.4 by the reference dimension are used.
When a resistor longer than 0.5 mm is combined (Comparative Example 5), and when an insulating cooling tube 0.5 mm shorter than the reference dimension and a resistor 0.5 mm longer than the reference dimension are combined (Comparative Example 6), Water leakage occurred even under no load condition.

In addition, even when a standard-sized one was used (Comparative Example 1), at the time when a load of 4 kW was absorbed, water leakage was considered to be caused by thermal expansion of the resistor. When an insulating cooling tube 0.1 mm shorter than the reference size and a resistor 0.1 mm longer than the reference size were combined (Comparative Example 2), no water leakage occurred under no load condition.
When a load of 3 kW is absorbed, water leakage occurs, and when an insulating cooling tube 0.2 mm shorter than the reference size and a resistor 0.2 mm longer than the reference size are combined (Comparative Example 3), a load of 2 kW is applied. At the time of absorption, water leakage occurred.

[0022]

According to the present invention, it is possible to sufficiently absorb variations in the overall length of the resistor and dimensional changes due to thermal expansion without requiring strict control to enhance the dimensional accuracy of the resistor. Provided is a water-cooled resistor that can reliably maintain water tightness between a cooling pipe and a cooling pipe holder, and has improved safety against water leakage. In addition, the cooling efficiency is high, it is possible to effectively absorb the load energy when a large amount of power is loaded, and it is possible to save space.It is extremely useful as a water-cooled resistor for large power circuits. is there.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a water-cooled resistor of the present invention.

FIG. 2 is a longitudinal sectional view showing one embodiment of a conventional water-cooled resistor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water-cooled type resistor of the invention 2 Insulating cooling pipe 3 Cooling pipe holder 4 Cooling pipe holder 5 Water supply port 6 Drain port 7 Resistor 8 Cooling water passage 9 Elastic body (compression coil spring) 10 Stat bolt 11 Elastic resin 12 Packing 13 Conventional water-cooled resistor

Claims (3)

[Claims] 1. An insulative cooling pipe is fixed at both ends in a watertight manner with a cooling pipe holder, a water supply port and a drain port are provided in one of the cooling pipe holders, and a resistor is disposed inside the insulating cooling pipe. In a water-cooled resistor in which cooling water is circulated inside the insulating cooling pipe to cool the resistor with water, an elastic body is interposed between the end of the resistor and the cooling pipe holder. A water-cooled resistor characterized by the following. 2. The water-cooled resistor according to claim 1, wherein the elastic body is interposed between the resistor and a cooling pipe holder provided with a water supply port and a drain port. 3. The water-cooled resistor according to claim 1, wherein the elastic body is a compression coil spring.