JP4399498B2 - Circuit breaker and thermal trip device - Google Patents

Description

  In the present invention, the fixed end of the bimetal whose one end is an operating end and the other end is a fixed end is fixed to the fixed terminal in a cantilever shape, and is overheated by an overcurrent flowing through the fixed terminal. A circuit breaker having a thermal trip device that causes the operation end to trip the circuit breaker body due to the bending of the bimetal, and a heater serving as a fixed terminal, one end is the operation end and the other end The fixed end portion of the bimetal, which is a fixed end portion, is fixed to the heater in a cantilevered manner, and when the heater is overheated by energization, the operating end portion of the bimetal is curved. Is.

  The thermal tripping device is a device that detects overcurrent in a circuit breaker and trips the main circuit of the circuit breaker body, for example, and the tripping characteristic when the overcurrent flows is The range is defined by standards such as JIS (Japanese Industrial Standard), which is an industrial standard, and products must satisfy it. However, in a thermal tripping device, variations in tripping characteristics are unavoidable due to product variations and material variations of components. Therefore, a structure for adjusting the tripping characteristic is usually incorporated, and the characteristic is adjusted and inspected.

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

  In measuring the bimetal temperature, there is also an idea that a non-contact measurement method is desirable because the measurement does not affect the bimetal bending amount. The reason is that in the measurement by the contact-type thermometer, the bimetal is subjected to a load from the outside through the probe, so that the bimetal is bent and the tripping characteristic is changed.

  In the non-contact temperature measurement method, a radiation thermometer incorporating an infrared absorption element is generally used. Non-contact temperature measurement in a conventional thermal tripping device of a circuit breaker heats the bimetal so that the bimetal temperature can be measured with a non-contact thermometer, for example, as seen in Patent Document 1. The heater is provided with a measurement window, and the temperature of the bimetal is measured with a radiation thermometer from the direction perpendicular to the bimetal surface through the window.

US Pat. No. 5,317,471 and drawings

  Although there is an idea that a non-contact temperature measurement method using a non-contact thermometer is desirable, since the bimetal surface is usually a metallic glossy surface, more accurate temperature measurement than a contact temperature measurement method using a contact thermometer There is a problem that is difficult. In addition, in the earth leakage breaker incorporating the earth leakage detection circuit and the circuit breaker downsized, there are few gaps around the bimetal, so there are many shields from the direction perpendicular to the bimetal surface by the non-contact thermometer. It is often difficult to measure the bimetal surface temperature from the outside.

  Therefore, it is preferable to realize a thermal tripping device that does not affect the tripping characteristics even if a contact thermometer is used, and a circuit breaker using such a thermal tripping device.

  The present invention has been made in view of the above-described circumstances, and is provided with a circuit breaker having a thermal trip device and a thermal trip device that do not affect trip characteristics even when a contact thermometer is used. The purpose is to provide a removal device.

  In the circuit breaker according to the present invention, the fixed end of the bimetal whose one end is an operating end and the other end is a fixed end is fixed to the fixed terminal in a cantilever manner, and an overcurrent flows through the fixed terminal. In the circuit breaker having a thermal trip device in which the operation end performs a trip operation of the circuit breaker main body due to the bending that is overheated by the temperature, a temperature measuring member is attached to the fixing portion of the bimetal to the fixed terminal However, the contact-type temperature measuring device is directly coupled to the bimetal and the fixed terminal so that the contact-type temperature measuring device can be contacted. Since the temperature of the bimetal can be measured in contact with the measurement member, the temperature of the bimetal can be measured without affecting the tripping characteristics.

  Further, the thermal tripping device according to the present invention is such that the fixed end of the bimetal whose one end is the operating end and the other end is the fixed end is cantilevered to the heater serving as the fixed terminal. In the thermal tripping device, in which the operating end of the bimetal is curved when the heater is overheated by energization of the heater, the temperature measuring member contacts the fixing portion of the bimetal to the heater. It is directly connected to the bimetal and the heater so that the temperature measuring device can be contacted, and is directly connected to the temperature measuring member without directly contacting the bimetal. Since the temperature of the bimetal can be measured, the temperature of the bimetal can be measured without affecting the tripping characteristic.

  In the present invention, the fixed end of the bimetal whose one end is an operating end and the other end is a fixed end is fixed to the fixed terminal in a cantilever shape, and is overheated by an overcurrent flowing through the fixed terminal. In the circuit breaker having a thermal trip device in which the operation end performs a tripping operation of the circuit breaker body due to bending, a temperature measuring member is attached to the fixed portion of the bimetal to the fixed terminal. Since it is directly coupled integrally to the bimetal and the fixed terminal so as to be able to contact the measuring device, the contact-type temperature measuring device is brought into contact with the temperature measuring member without directly contacting the bimetal. The temperature of the bimetal can be measured, and therefore the temperature of the bimetal can be measured without affecting the tripping characteristics. Compared with the case of employing a non-contact temperature measuring method using a touch thermometer, it is possible to highly accurate temperature measurement.

  In the present invention, the fixed end of the bimetal whose one end is an operating end and the other end is a fixed end is fixed to the heater in a cantilever manner, and the heater is energized. In the thermal tripping device in which the operating end of the bimetal is curved when overheated by the temperature measuring member, the temperature measuring member can contact the contact-type temperature measuring device to the fixing portion of the bimetal to the heater. Since it is directly coupled to the bimetal and the exposed state from the heater, the temperature of the bimetal can be measured by contacting the temperature measuring member without directly contacting the bimetal with the contact-type temperature measuring device. The bimetal temperature can be measured without affecting the tripping characteristics, and the contact-type temperature measurement method is used. Compared with the case of adopting the method, it is possible to highly accurate temperature measurement.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS. 1 is a side view showing a mechanism part in a case of a circuit breaker having a thermal tripping device, FIG. 2 is an enlarged perspective view showing the thermal tripping device of FIG. 1, and FIG. FIG. 4 is a perspective view for explaining a method of measuring a bimetal temperature by a contact temperature measuring device, and FIG. 5 is a diagram showing a state where power is supplied to a fixed terminal (that is, a heater). It is an enlarged side view for demonstrating the bending operation | movement of the bimetal in a case. 1 to 5, the same parts are denoted by the same reference numerals.

In FIG. 1, the operation when an overcurrent greater than the rated current flows through the circuit breaker is as follows.
(1) When an overcurrent flows through the heater 1 or the bimetal 2, the temperature of the heater 1 or the bimetal 2 rises.
(2) The bimetal 2 bends as the temperature of the bimetal 2 increases.
(3) The bending amount of the bimetal 2 increases, and the trip bar 3 is pushed.
(4) The mechanism unit 4 operates to instantaneously shut off (trip) the main circuit 5.

  The range from the start of overcurrent to the trip is defined by the standards such as JIS, and the product trip time must satisfy the range. However, the operating point of the tripping mechanism, that is, the position at which the bimetal 2 pushes the trip bar 3 varies due to the accumulation of manufacturing variations such as processing / assembly errors of each component constituting the tripping mechanism, variations in material characteristics, Variation occurs in the time (trip time) from the start of energization to the trip. Therefore, in order to absorb such manufacturing variations, an adjustment mechanism 6 is provided at the tip of the bimetal 2 and the trip bar 3, and adjustment / inspection work is performed in the assembly process.

  In adjustment / inspection work, it is necessary to accurately measure the tripping characteristics of each workpiece. Usually, the trip characteristic is often measured by energizing a predetermined current value and measuring the trip time or measuring the amount of bimetal displacement during that time. However, since the trip time and bimetal displacement are greatly affected by the workpiece temperature and measurement environment temperature at the start of energization, measure the trip time or a measured value based on the workpiece temperature or ambient temperature. Must be corrected.

  On the other hand, the bending amount (displacement amount) of the bimetal is determined by the temperature and the bending coefficient. However, since the bending coefficient is known, the displacement amount can be obtained by measuring the bimetal temperature. Therefore, the trip characteristic can be measured by measuring the bimetal temperature.

  In order to measure the bimetal temperature, a non-contact type radiation thermometer is generally used as described above. This is because when a contact-type thermometer is used, the tripping characteristic is changed due to the bending of the bimetal due to the contact load of the measuring element, and the tripping characteristic cannot be measured accurately.

  A non-contact thermometer measures the temperature of an object by detecting the amount of infrared radiation radiated from the object. The amount of infrared radiation radiated from an object varies depending on the material and its surface state, and the amount of infrared energy (emissivity) radiated differs even at the same temperature. In the non-contact type thermometer, the temperature is calculated based on an ideal black body (theoretical object having an emissivity of 100%), and other objects must be corrected according to the individual emissivity.

  Since the emissivity is usually obtained experimentally, and it is difficult to obtain the emissivity of the measurement object in a short time, the emissivity cannot be obtained for each workpiece in the mass production process. Therefore, when the emissivity of the bimetal varies, the variation becomes a variation in temperature measurement. Furthermore, since the bimetal surface is generally a metallic gloss surface, infrared rays radiated from a heat source of an object near the bimetal such as a heater are easily reflected on the bimetal surface. If the reflected light enters the radiation thermometer, a measurement error occurs.

  Therefore, in the first embodiment of the present invention, the temperature can be measured at a portion where the bimetal 2 is curved to push the trip bar 3, that is, at a location different from the operation end portion 21. As a result, temperature measurement using a contact-type thermometer is possible without affecting the amount of bending of the operating end portion 21 of the bimetal 2, and temperature measurement can be stably performed with high accuracy compared to a conventional non-contact-type thermometer.

  In the heating of the bimetal 2, it is difficult to uniformly heat the entire bimetal 2, and thus a temperature distribution exists in the bimetal 2. In other words, when the fixed end 22 of the bimetal whose one end is the operating end 21 and the other end is the fixed end 22 is fixed to the fixed terminal (that is, the heater) 1 in a cantilever manner, That is, the temperature of the operating end 21 is slightly lower than the temperature of the fixed end 22 fixed to the heater 1. However, since the relationship between the temperature distribution in the bimetal 2 and the bending amount of the operating end 21 of the bimetal 2 is obtained in advance depending on the material and size of the bimetal 2, even if the temperature of the fixed end 22 is measured, the temperature The desired amount of bending of the operating end 21 of the bimetal 2 can be obtained. Conversely, the standard temperature of the fixed end 22 when the operating end 21 of the bimetal 2 has the desired amount of bending (that is, when the amount of bending that causes the circuit breaker to trip) is obtained. Can do. In other words, the fixed end when the operation end 21 of the bimetal 2 has the desired amount of bending (that is, when the amount of bending causes the circuit breaker to trip, or when the circuit breaker trips). If the measured temperature of the part 22 is the same as the standard temperature, it can be said that the tripping characteristic of the thermal tripping device is a predetermined tripping characteristic.

  Therefore, in the first embodiment of the present invention, the temperature of the added temperature measurement member 7 is brought into contact by adding a part having a temperature equivalent to the temperature of the fixed end portion 22 of the bimetal 2, that is, the temperature measurement member 7. The temperature of the fixed end 22 of the bimetal 2 can be measured by the thermometer instead of directly measuring the temperature of the fixed end 22 of the bimetal 2. That is, as shown in FIG. 4, the temperature of the bimetal 2 is indirectly measured by measuring the temperature of the temperature measuring member 7 by bringing the probe 81 of the contact-type thermometer 8 into contact with the temperature measuring member 7. Can be measured.

  2 to 4, the temperature measuring member 7 is connected to the fixing portion 221 of the bimetal 2 to the fixed terminal (that is, the heater) 1, and the temperature measuring member 7 is connected to the contact temperature. In order to be able to contact the measuring element 81 of the measuring instrument 8, the measuring element 81 is directly coupled integrally with the bimetal 2 and the fixed terminal (ie, heater) 1. That is, as shown in the drawing, the entire area of the temperature measuring member 7 is larger than the area of the portion of the temperature measuring member 7 facing the fixed terminal (ie, heater) 1.

  Further, it exists between the bimetal 2 and the fixed terminal (i.e., heater) 1, and is firmly fixed to the fixed terminal (i.e., heater) 1 together with the bimetal 2 by a plurality of caulking stoppers 9. That is, the fixed end 22 of the bimetal 2, the temperature measuring member 7 and the fixed terminal (ie, heater) 1 are in close contact with each other by the caulking stopper 9, and are maintained in an excellent thermal connection state. It is supposed to be.

  The inspection of the tripping characteristic is performed with the thermal tripping device shown in FIGS. 2 to 5 alone, or with the thermal tripping device incorporated in the circuit breaker as shown in FIG. However, in that case, when a current corresponding to a predetermined overcurrent is passed through the fixed terminal (ie, heater) 1, the operating end 21 of the bimetal 2 is as shown by a one-dot chain line, as shown in FIG. The temperature measuring member 7 is also bent in the same direction as the operation end 21 of the bimetal 2 as shown by a one-dot chain line.

  The temperature measuring member 7 is formed of the same material as the bimetal 2 (that is, when the bimetal 2 is a bonding material of iron and copper, the temperature measuring member 7 is also a bonding material of iron and copper. And the length of the temperature measuring member 7 is shorter than the length of the bimetal 2, so that the operating end 21 and the temperature measuring member 7 of the bimetal 2 are curved as shown by a one-dot chain line. However, since the amount of bending of the temperature measuring member 7 is smaller than the amount of bending of the operating end 21 of the bimetal 2, the temperature measuring member 7 is interposed between the tip of the temperature measuring member 7 and the operating end 21 of the bimetal 2. However, there is a slight gap g. Therefore, the temperature measuring member 7 does not come into contact with and press against the operating end 21 of the bimetal 2 due to its curvature, and the bending amount of the operating end 21 of the bimetal 2 is adversely affected. No.

  When the temperature measuring member 7 is bent opposite to the one-dot chain line in FIG. 5, the operating end 21 of the bimetal 2 is pressed during the bending, and the operating end of the bimetal 2 is pressed. Since the amount of bending of the portion 21 is adversely affected, it must be avoided to bend in the direction opposite to the one-dot chain line in FIG.

Embodiment 2. FIG.
The second embodiment of the present invention will be described below with reference to FIGS. 6 is a perspective view showing a thermal tripping device, FIG. 7 is a side view showing the thermal tripping device, and FIG. 8 is a diagram for explaining a bimetal bending operation when a fixed terminal (ie, heater) is energized. FIG.

  In the second embodiment of the present invention, as shown in FIGS. 6 to 8, the temperature measuring member 7 extends from the fixed portion 221 of the bimetal 2 to the side opposite to the operating end portion 21 of the bimetal. This is an example of the case.

  In this case, the temperature measuring member 7 is formed by extending the bimetal 2 itself to the side opposite to the operation end 21. In other words, the temperature measuring member 7 has the bimetal 2 and the fixed terminal (that is, the heater) so that the contact temperature measuring device 8 can be brought into contact with the fixing portion 221 of the bimetal 2 to the fixed terminal (that is, the heater) 1. ) 1 is exposed directly from 1 and is directly coupled together and extends from the fixing portion 221 of the bimetal 2 to the side opposite to the operation end portion 21 of the bimetal.

  In the case of Embodiment 2 of the present invention, as shown in FIGS. 7 and 8, the tip of the probe 81 of the contact-type temperature measuring device 8 is brought into contact with the lower surface of the temperature measuring member 7 and the temperature measuring member 7. The temperature of the bimetal 2 is indirectly measured by measuring the temperature.

  In the case of the second embodiment of the present invention, even if the temperature measuring member 7 is curved as shown by a one-dot chain line by passing a current corresponding to a predetermined overcurrent to the fixed terminal (that is, the heater) 1, A slight gap G is formed between the tip of the temperature measuring member 7 and the fixed terminal (ie, heater) 1. Therefore, when the temperature measuring member 7 comes into contact with the fixed terminal (ie, heater) 1 due to its curvature, no force is applied to the fixed end portion 22 of the bimetal 2, and the operating end of the bimetal 2 is not affected. There is no adverse effect on the bending amount of the portion 21.

Embodiment 3 FIG.
In Embodiment 3 of the present invention, as shown in FIG. 9, a measuring element insertion through-hole having a diameter larger than the diameter of the measuring element 81 of the contact-type temperature measuring device 8 is provided in the fixed terminal (ie, heater) 1. 12a is provided, and the measuring element 81 is inserted into the measuring element insertion through hole 12a so as not to contact the fixed terminal (that is, the heater) 1, and the tip of the measuring element 81 is inserted into the temperature measuring member 7. The temperature of the bimetal 2 is indirectly measured by contacting the lower surface and measuring the temperature of the temperature measuring member 7. Even if comprised in this way, there exists the same effect as above-mentioned Embodiment 2 of this invention.

  In the third embodiment of the present invention, specifically, as shown in the drawing, the measurement is applied to the internal terminal portion 12 at the end opposite to the external terminal portion 11 having the connection hole 11a in the circuit breaker. A child insertion through hole 12a is provided.

Embodiment 4 FIG.
As shown in FIG. 10, the third embodiment of the present invention has a structure in which the internal terminal portion 12 extends long to the inside of the circuit breaker body, and the inside of the circuit breaker body from the measuring element insertion through hole 12a. A connection hole 12b for connecting to a connection terminal (not shown) inside the circuit breaker body is provided at a position separated by a predetermined distance to the connection terminal (not shown) inside the circuit breaker body. Easy to do.

It is a figure which shows Embodiment 1 of this invention, and is a side view which shows the mechanism part in the case of the circuit breaker which has a thermal tripping device. FIG. 2 is a diagram showing the first embodiment of the present invention, and is an enlarged perspective view showing the thermal tripping device of FIG. 1. It is a figure which shows Embodiment 1 of this invention, and is a side view which expands and shows the thermal tripping apparatus of FIG. It is a figure which shows Embodiment 1 of this invention, and is a perspective view for demonstrating how to measure the bimetal temperature by a contact-type temperature measuring device. It is a figure which shows Embodiment 1 of this invention, and is an enlarged side view for demonstrating the bending | flexion operation | movement of a bimetal at the time of supplying with electricity to a fixed terminal (namely, heater). It is a figure which shows Embodiment 2 of this invention, and is a perspective view which shows a thermal trip device. It is a figure which shows Embodiment 2 of this invention, and is a side view which shows a thermal tripping device. It is a figure which shows Embodiment 2 of this invention, and is an enlarged side view for demonstrating the bending | flexion operation | movement of a bimetal at the time of supplying with electricity to a fixed terminal (namely, heater). It is a figure which shows Embodiment 3 of this invention, and is a side view which shows a thermal trip device. It is a figure which shows Embodiment 4 of this invention, and is a side view which shows a thermal trip device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixed terminal (heater) 11 External terminal part 11a Connection hole 12 Internal terminal part 12a Measuring element insertion through-hole 12b Connection hole 2 Bimetal 21 Operation end part 22 Fixed end part 221 Adhering part 3 Trip bar 4 Mechanism part 5 Main circuit 6 Adjustment Mechanism 7 Temperature measuring member 8 Contact type thermometer 81 Measuring element 9 Clamping g gap G gap G gap.

Claims (10)

The fixed end of the bimetal whose one end is an operating end and the other end is a fixed end is fixed to the fixed terminal in a cantilever shape, and is bent by the overheating of the bimetal due to an overcurrent flowing through the fixed terminal. In the circuit breaker having a thermal trip device in which the operation end performs a trip operation of the circuit breaker body, a temperature measurement member is a contact-type temperature measurement device at a fixing portion of the bimetal to the fixed terminal. A circuit breaker that is directly coupled to the bimetal and the fixed terminal so as to be in contact with each other. 2. The circuit breaker according to claim 1, wherein the temperature measuring member exists between the bimetal and the fixed terminal and is fixed to the fixed terminal together with the bimetal. 2. The circuit breaker according to claim 1, wherein the temperature measuring member extends from the fixed portion of the bimetal to the side opposite to the operation end portion of the bimetal. 4. The circuit breaker according to claim 1, wherein the temperature measuring member is formed of the same bimetal as the bimetal, and is bent in a direction away from the fixed terminal when overheated by an overcurrent flowing through the fixed terminal. A circuit breaker characterized by: The fixed end of the bimetal whose one end is an operating end and the other end is a fixed end is fixed to the heater in a cantilever manner and is overheated by energizing the heater. In the thermal tripping device in which the operating end of the bimetal is curved, the bimetal and the heater so that the temperature measuring member can contact the contact-type temperature measuring device to the fixing portion of the bimetal to the heater A thermal tripping device, wherein the thermal tripping device is directly coupled integrally to the exposed state. 6. The thermal tripping device according to claim 5, wherein the temperature measuring member exists between the bimetal and the heater and is fixed to the heater together with the bimetal. Removal device. The thermal trip device according to claim 6, wherein the area of the temperature measurement member is larger than the area of the portion of the temperature measurement member facing the heater. . 6. The thermal tripping device according to claim 5, wherein the temperature measuring member extends from the fixing portion of the bimetal to the side opposite to the operation end portion of the bimetal. Type trip device. 9. The thermal tripping device according to claim 8, wherein the heater is provided with a probe insertion through hole having a diameter larger than the diameter of the probe of the contact temperature measuring device. Removal device. 10. The thermal tripping device according to claim 5, wherein the temperature measuring member is formed of the same bimetal as the bimetal, and is bent in a direction away from the heater when overheated by energization of the heater. A thermal tripping device characterized in that:

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