KR100765673B1 - Thermal type tripping device and circuit breaker using the same - Google Patents

Abstract

In a thermal trip device in which a bimetal 2 is heated by an overcurrent, and a tripping operation of a circuit is performed by bending of the heated bimetal 2, at least a part of the surface of the bimetal 2 is black or matte. It is made of black (7). Thereby, it becomes possible to measure the temperature of the bimetal 2 with high precision using a non-contact thermometer. Moreover, the bending process part 11 was provided in the temperature measurement part 8 of bimetal, and the surface was made into the matte black.

Description

Thermal tripping device and circuit breaker using it {THERMAL TYPE TRIPPING DEVICE AND CIRCUIT BREAKER USING THE SAME}

The present invention relates to a thermal trip device and a circuit breaker using the same.

A thermal trip device is a device which detects an overcurrent in a circuit breaker and trips a main circuit, for example. The trip characteristic when an overcurrent flows is defined by the standards, such as JIS, and the product needs to satisfy | fill it. However, in the thermal trip device, the gap of the trip characteristic cannot be avoided due to the production gap of the components to be formed and the gap of the raw materials. Therefore, usually, the structure for adjusting a trip characteristic is incorporated, and the characteristic is adjusted and inspected.

In order to adjust and test a trip characteristic, it is necessary to measure the characteristic value correctly. In the thermal trip device, the trip characteristic is often measured by measuring a time (trip time) from the start of energization to the completion of the trip and the amount of bimetal displacement by energizing a predetermined current. On the other hand, since the curvature coefficient of a bimetal is known, the amount of bimetal displacement can be calculated | required by measuring bimetal temperature. Therefore, the trip characteristic can be grasped | ascertained by measuring bimetal temperature.

When measuring bimetal temperature, the method of non-contact measurement is preferable, in order not to affect a bimetal curvature amount by measurement. In the measurement by a contact thermometer, since a load is applied to the bimetal from the outside through a measuring instrument, the bimetal is warped and the trip characteristic is changed. As a non-contact temperature measuring method, it is common to use the radiation thermometer which incorporated the infrared absorption element.

However, since the conventional bimetallic surface is a metallic gloss surface, there is a problem in that accurate thermometer side is difficult. In addition, in an earth leakage circuit breaker in which an earth leakage detection circuit has been incorporated or a miniaturized circuit breaker, since there are few gaps around the bimetal, it is difficult to measure the bimetal surface temperature from the outside.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a thermal trip device that can measure a bimetal temperature with high accuracy using a non-contact thermometer and a circuit breaker using the same.

Summary of the Invention

The thermal trip device according to the present invention is a thermal trip device in which a bimetal is heated by an overcurrent, and a trip operation of a circuit is performed by the curvature of the heated bimetal, wherein at least a part of the surface of the bimetal is black or matte. It is black.

Thereby, it becomes possible to measure bimetallic temperature with high precision using a non-contact thermometer.

Moreover, this invention makes the surface of the bimetallic temperature measuring part black or matte black.

Moreover, in this invention, the bending process part bent at substantially right angle to the bimetallic longitudinal direction is provided in the temperature measurement part of a bimetal, The surface is made into black or matte black.

Thereby, even in the model which is difficult to measure from the substantially vertical direction of a bimetallic surface, it is stable and a high density thermometer side is attained.

Moreover, this invention provides the bending process part bend | folded at substantially right angle to the longitudinal direction of a bimetal in the temperature measurement part of a bimetal.

Thereby, measurement can be performed from the longitudinal direction of a bimetal, and it becomes stable and a high density thermometer side is attained.

1 is a perspective view showing a bimetal part of a thermal trip device according to Embodiment 1 of the present invention;

2 is a perspective view showing a bimetal part of the thermal trip device according to the second embodiment;

3 is a perspective view showing a bimetal part of the thermal trip device according to the embodiment of the present invention;

4 is a perspective view showing a bimetal part of the thermal trip device according to the fourth embodiment;

5 is a plan view showing a material processing step for bimetal according to the second embodiment;

6 is a plan view showing a material processing step of bimetal according to the third embodiment;

FIG. 7 is a view showing a state of measuring the temperature of the bimetal of Embodiment 3 using a non-contact thermometer; FIG.

FIG. 8 is a view showing a state of measuring the temperature of the bimetal of Embodiment 4 using a non-contact thermometer;

9 is a partial cutaway front view illustrating the structure of a circuit breaker having a thermal trip device.

Embodiment 1.

The circuit breaker is a safety device to prevent an accident by breaking the circuit when an overcurrent exceeding the rating flows. In the circuit breaker, a mechanism for detecting an overcurrent is called a trip mechanism, and there is a thermal type using bimetal as one of the detection means. This is because the bimetal bends due to temperature changes. 9 is a partial cutaway front view showing the structure of a thermal trip mechanism, that is, a circuit breaker provided with a thermal trip mechanism.

The operation | movement when overcurrent more than a rated current flows is as follows.

(1) The overcurrent flows through the heater 1 or the bimetal 2, whereby the temperature of the heater 1 or the bimetal 2 increases.

(2) The bimetal 2 is curved as the temperature of the bimetal 2 rises.

(3) The curvature amount of the bimetal 2 increases, and the trip bar 3 is pushed.

(4) The mechanism part 4 operates to cut off the main circuit 5 immediately (trip).

The time from the start of the overcurrent to the trip is determined by a standard such as JIS, and the trip time of the product must satisfy the range. However, the operating point of the trip mechanism, that is, the position where the bimetal 2 presses the trip bar 3 is caused by the accumulation of manufacturing gaps such as processing and assembly errors of the respective components constituting the trip mechanism, and gaps in material properties. There is a change in the time (trip time) from the start of energization to the trip. Therefore, in order to absorb such a manufacturing gap, the adjustment mechanism 6 is provided in the tip of the bimetal 2 and the trip bar 3, and the adjustment and inspection work is performed in an assembly process.

In the adjustment and inspection work, it is necessary to accurately measure the trip characteristic for each work. Usually, the trip characteristic is measured by measuring a trip time by energizing a predetermined current value or by measuring the amount of bimetal displacement during that time. However, since the trip time and the bimetal displacement amount are greatly influenced by the work temperature and the measurement environment temperature at the start of energization, the measured value must be measured in a controlled state at a constant temperature or the measured value must be corrected according to the work temperature or the ambient temperature. .

On the other hand, although the curvature amount (displacement amount) is determined by the temperature and curvature coefficient of a bimetal, since a curvature coefficient is known, a displacement amount can be calculated | required by measuring bimetal temperature. Therefore, it is possible to measure a trip characteristic by measuring bimetal temperature.

In order to measure a bimetal temperature, generally a non-contact radiation thermometer is used. This is because, when the contact thermometer is used, the bimetal warpage occurs due to the contact load of the measurer, which causes the trip characteristic to change, and thus an accurate trip characteristic cannot be measured.

Non-contact thermometers measure the temperature of an object by detecting the amount of radiation energy of infrared radiation emitted from the object. The amount of infrared radiation emitted from an object differs depending on the material and its surface state, and the amount of infrared energy (emissivity) emitted even at the same temperature is different. In the non-contact thermometer, the temperature is calculated on the basis of an ideal black body (theoretical object of 100% emissivity), and other objects must be corrected according to the respective emissivity.

Emissivity is usually obtained experimentally, and it is difficult to obtain the emissivity of the measurement object in a short time, and thus the emissivity cannot be determined for each work in a mass production process. Therefore, when the bimetallic emissivity changes, the gap becomes a gap on the thermometer side. In addition, since the bimetal surface is generally made of a metallic gloss surface, infrared rays emitted from heat sources other than those near the bimetal such as a heater are likely to be reflected on the bimetal surface. When the reflected light enters the radiation thermometer, it becomes a measurement error.

In addition, even if the emissivity is low, the temperature can be measured by correcting according to the emissivity. However, since the absolute amount of infrared rays decreases, the noise component in the measurement increases, and the temperature measurement accuracy decreases. Therefore, for high precision temperature measurement, emissivity is high and constant is desired.

Therefore, in the present invention, emissivity is made high and constant by making the surface serving as the temperature measuring section of the bimetal 2 black, preferably matt black 7 (see Fig. 1). As a result, a constant high emissivity is obtained even in other workpieces, so that the bimetal temperature can be measured stably with high accuracy. Moreover, by setting it as a matte coating, reflection from another heat source can be suppressed and a measurement error can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the bimetal part of the thermal tripping apparatus in Embodiment 1 of this invention. In order to make it black, there exists a method by coating or etching, for example. In order to make matte black, you may use black paint for matte. Moreover, you may make it matt black by oxidizing with an etching. In this case, as the etching solution, for example, a sodium hydroxide solution or a phosphate solution is used when the bimetal 2 is an iron-based material, and an acidic aqueous solution containing selenium, for example, is used when the material is copper-based. do.

Embodiment 2.

In order to measure bimetal temperature with high precision, it is necessary to fix the temperature measuring position in bimetal, ie, the temperature measuring part 8 (refer FIG. 2). This is because in the heating of the bimetal 2 by the heater, it is difficult to uniformly heat the whole bimetal, so that a temperature distribution exists in the bimetal 2. Therefore, what is necessary is just to perform the blackening process of the surface of the bimetal 2 described in Embodiment 1 in a temperature measuring part. FIG. 2 is a perspective view illustrating a bimetal part of the thermal trip device according to the second embodiment. FIG.

Usually, the bimetal 2 used for a circuit breaker is manufactured by press working from the elongate bimetallic material 9 (refer FIG. 5). Therefore, the bimetal piece which blackened only the part which becomes a thermometer side part in the step of the raw material 9 as black, preferably matte black 7 and press-processes it can be obtained. 5 is a plan view showing a material processing step of bimetal according to the second embodiment. The machining process can be simplified in the case where the material is collectively processed in the raw material state rather than blackening in the state of the bimetallic piece, thereby reducing the processing cost. In addition, by minimizing the treated portion as in the second embodiment, the processing cost is further reduced.

Embodiment 3.

An example in which two black portions are provided in the bimetallic material 9 is shown in FIG. 6. The shape of the bimetal is gradually narrowed toward the tip, and in this case, the yield of the raw material 9 can be increased by press-working by combining the directions of the bimetal piece alternately. The bimetallic material 9 is taken out from a roll-shaped raw material, and two black parts are provided, and it is press-processed as shown in FIG. The perspective view of the main part of the thermal trip apparatus using the bimetal formed in Embodiment 3 is shown in FIG.

Embodiment 4.

In order to measure the temperature of the bimetal using a non-contact thermometer, a space is provided in which the thermometer is provided in a substantially vertical direction from the temperature measurement section 8 of the bimetal, and there is no obstacle blocking the infrared rays in the meantime. FIG. 7: is a figure which shows the mode which measures the temperature of the bimetal 2 of Embodiment 3 using the non-contact thermometer 10. As shown in FIG.

However, in the ground fault circuit breaker, for example, the ground fault detection unit is incorporated adjacent to the bimetal, and thus the space cannot be secured in many cases. In addition, in circuit breakers, the locations where the bimetal temperature can be measured are limited due to the miniaturization of the product, and it may be impossible to measure the ideal temperature measurement point of the bimetal phase. Embodiment 4 enables the thermometer side at a desired place even in this case.

The perspective view of the bimetal part of the thermal trip apparatus in Embodiment 4 is shown in FIG. The bending process part 11 is provided in the part used as the bimetal temperature measurement part 8.

As shown in FIG. 8, the bend-processing part 11 is provided in the bimetal temperature measurement part 8 substantially perpendicular to the longitudinal direction of the bimetal 2 so that temperature measurement may be performed from the longitudinal direction of the bimetal. As a thermal trip device, there is a space which can be measured in the longitudinal direction of the bimetal 2 because a space for the bimetal 2 needs to be bent and a trip characteristic needs to be adjusted. However, in the conventional bimetal, since there is no part which can measure only as much as plate | board thickness from this direction, temperature measurement is very difficult.

Therefore, by bending the part to be the temperature measuring part 8 of the bimetal 2, installing the bent part 11, and securing the required area on the thermometer side, as shown in FIG. The side of the thermometer by the non-contact thermometer 10 becomes possible in parallel to the longitudinal direction. By changing the position at which the bending process is performed, the thermometer side at any place of the bimetal is possible.

In addition, when the temperature side is performed on the surface of the bent portion, a black, preferably matte black color is obtained after the bending process or before the bending process, whereby the bimetal temperature can be more accurately measured. .

As described above, the thermal trip device of the present invention can measure the bimetal temperature with high accuracy using a non-contact thermometer, so that the amount of bimetal displacement can be accurately calculated and suitable for application to the circuit breaker. The characteristics of can be stabilized easily.

Claims (8)

In a thermal trip device in which a bimetal is heated by an overcurrent, and a trip operation of a circuit is executed by the curvature of the heated bimetal, At least a part of the surface of the bimetal is black. Thermal trip device. The method of claim 1, At least a part of the surface of the bimetal is matte black, characterized in that Thermal trip device. The method of claim 1, The surface of the temperature measurement part of the bimetal was made black. Thermal trip device. The method of claim 3, wherein The surface of the said temperature measuring part of bimetal was made into the matte black, It is characterized by the above-mentioned. Thermal trip device. The method of claim 3, wherein In the said temperature measurement part of bimetal, the bending process part bend | folded substantially perpendicular to the longitudinal direction of bimetal was provided, and the surface was made black. Thermal trip device. The method of claim 4, wherein In the said temperature measurement part of bimetal, the bending process part bend | folded substantially perpendicularly to the bimetallic longitudinal direction was provided, and the surface was made into the matte black, It is characterized by the above-mentioned. Thermal trip device. In the thermal trip device which heats a bimetal by an overcurrent, and performs a trip operation of a circuit by the curvature of a heated bimetal, In the temperature measurement part of bimetal, the bending process part bent at substantially right angle to the longitudinal direction of bimetal is provided, It is characterized by the above-mentioned. Thermal trip device. In the circuit breaker which has a thermal trip device which heats a bimetal by an overcurrent, and performs a trip operation of a circuit by the curvature of a heated bimetal, The surface of the temperature measurement part of the bimetal was made black. Circuit breaker.

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