JP5656899B2 - Method of manufacturing thermal trip device and circuit breaker using thermal trip device manufactured by the manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a thermal tripping device and a circuit breaker using the thermal tripping device manufactured by the manufacturing method.

The circuit breaker overcurrent tripping device has a bimetal curve when the current flowing through the circuit is overloaded, and when a large current such as a short circuit current flows through the circuit, the overcurrent tripping device is an electromagnet. By instantly sucking the movable iron core and releasing the lock of the opening / closing mechanism, the opening / closing lever is rotated to open the movable contact.
For example, a thermal relay as shown in FIG. 5 is known as a thermal trip device having an overload protection function. FIG. 5 is a schematic view of only the main part seen from the plane. The thermal relay is made of bimetal or the like, and has a thermal element 21 that is erected in the direction perpendicular to the paper surface corresponding to each of the three phases. The thermal relay is in contact with one side surface of the thermal element 21 and heat caused by an increase in energization current. The first interlocking plate 22 that is pushed by the deformation of the moving element 21, the second interlocking plate 23 that is in contact with the opposite side surface of the thermodynamic element 21, and the difference in which one end is pivotally attached to the end of the second interlocking plate 23. And a moving lever 24. The end of the first interlocking plate 22 abuts on an abutment pin 25 provided at an intermediate portion of the differential lever 24. Accordingly, the displacement amount of any one of the thermal elements 21 becomes smaller than the displacement amount of the other thermal elements 21 at the time of phase loss or the like, so that the first interlock plate 22 and the second interlock plate 23 A difference occurs in the amount of displacement, the differential lever 24 rotates at an angle corresponding to this difference, and the operation plate 26 for opening and closing the contact device is pressed. On the other hand, during overload, the first interlocking plate 22 is displaced by a predetermined amount and presses the differential lever 24 to press the operating plate 26 (see Patent Document 1).

JP-A-5-274986 (2nd page, FIG. 20)

In order to satisfy the breaking characteristics of a circuit breaker incorporating a thermal trip device, the distance between the thermal element and the interlocking plate needs to be assembled as designed. There is a correlation between the amount of displacement of the thermal element during energization and the amount of movement of the interlocking plate, and variations in the amount of bending of the thermodynamic element during energization affect the amount of movement of the interlocking plate and the differential lever.
When the interlocking plate is moved by the displacement of the thermal element bent when energized and contacted with the operating plate via the differential lever to perform the shut-off operation, if the mounting dimensions of the thermal element vary, the differential lever and the operating plate Unlike the design value, the distance between the two causes a variation in cutoff characteristics.
In a conventional thermal relay as shown in Patent Document 1, as an assembling procedure, a thermal element is attached to the body side, and then an interlocking plate having a fixed size is attached. Alternatively, a method of incorporating the first interlocking plate on the body side before incorporating the thermal element is also shown. In any case, if the thermal element is not arranged at the designed position due to variations in the dimensions of the thermal element or the assembly position, a gap is generated between the interlocking plate.

  In order to avoid this, the problem has been solved by adjusting the position of the thermal element manually to eliminate the gap formed between the thermal element and the interlocking plate. This method requires a lot of work time for adjustment, and the thermal element is adjusted by applying an excessive force after assembly, so that it contacts a part of the electric circuit or a heater that is a part of the electric circuit. This causes a variation in contact resistance between conductive parts such as bimetals, and causes a variation in the shut-off operation.

  The present invention has been made to solve the above-described problems, and a method for manufacturing a thermal trip device that can easily perform assembly and adjustment work, and a thermal trip manufactured by the manufacturing method. An object of the present invention is to provide a circuit breaker using a removing device.

The manufacturing method of the thermal tripping device according to the present invention includes a plurality of thermal elements arranged in parallel with the direction of bending displacement by electric heating and the operation end portions of the thermal elements interposed therebetween. A first interlocking plate that is disposed on both sides and has a contact portion that contacts one surface of the operating end, a second interlocking plate that has a contact portion that contacts the other surface, and a first interlocking plate And a phase-opening cam that is swingably connected across both interlocking plates of the second interlocking plate, and a transmission piece that transmits the displacement of the phase-stopping cam to the opening / closing mechanism of the circuit breaker. Manufacturing method of a thermal tripping device, in which a plurality of thermal elements are attached to an insulating housing in which the thermal tripping device is incorporated, and before the two interlocking plates are incorporated , the mounting dimensions of the thermal actuator by the measuring device the obtains a difference between the design value by measuring, in a processing apparatus for processing both interlock plate, based on the difference information The respective dimensions of the contact portion of the interlock plate and the second interlock plate 1 is processed by correcting, in which so as to incorporate both interlock plate processed into a thermally activated element.

  In addition, the circuit breaker according to the present invention opens and closes an insulating housing, a fixed contact mounted on the insulating housing, a movable contact disposed opposite to the fixed contact, and a movable contact. An opening / closing mechanism and a thermal tripping device that operates the opening / closing mechanism in response to an overcurrent during energization. The thermal tripping device is a thermal tripping device manufactured by the above manufacturing method. The device is in use.

According to the manufacturing method of the thermal tripping device of the present invention, a plurality of thermal elements are attached to an insulating housing in which the thermal tripping device is incorporated, and the thermal measurement is performed by the measuring device in a state before both interlocking plates are incorporated. In a processing apparatus that measures the mounting dimension of the moving element to obtain a difference from the design value and processes both interlocking plates , based on the difference information, each of the contact portions of the first interlocking plate and the second interlocking plate Since both the processed interlocking plates are incorporated into the thermal element, the dimensions are corrected, and the contact area between the thermal element and the interlocking plate can be assembled almost without any gaps. The assembly accuracy of the interlocking plate due to the variation in the mounting position of the element is improved. In addition, since the variation of the interruption operation due to the displacement of the thermal element during energization is reduced, the operation accuracy at the time of interruption due to overcurrent can be improved.

  In addition, according to the circuit breaker of the present invention, since the thermal trip device manufactured by the above manufacturing method is used, the assembly accuracy of the thermal element and the interlocking plate is improved, and at the time of the interruption due to overcurrent A circuit breaker having excellent operation accuracy can be obtained.

It is explanatory drawing explaining the manufacturing process of the interlocking board part of the manufacturing method of the thermal tripping device by Embodiment 1 of this invention. 1 is a perspective view of a thermal trip device according to Embodiment 1 of the present invention. FIG. It is a side view of the circuit breaker using the thermal tripping device by Embodiment 1 of this invention. FIG. 4 is a plan view of FIG. 3. It is a top view which shows typically the principal part of the conventional thermal trip device.

Embodiment 1 FIG.
FIG. 1 is an explanatory view for explaining the manufacturing process of the interlocking plate portion of the manufacturing method of the thermal tripping device according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view of the thermal tripping device portion. FIG. 3 is a side view of a circuit breaker using the thermal tripping device according to Embodiment 1, and FIG. 4 is a plan view of FIG.
First, an outline of a circuit breaker having a built-in thermal trip device will be described with reference to FIGS.

  The circuit breaker has a main body housed in an insulating casing 1 and a casing cover 2 made of resin, and opens and closes the circuit breaker between the power supply side terminal 3 and the load side terminal 4. An overload tripping device 7 has a mechanism 5 and a handle 6 for operating the switching mechanism 5 to turn on and off the circuit in the circuit breaker, and further detects a short circuit in the circuit and instantaneously interrupts the circuit breaker. And a thermal trip device 8 that detects overload and phase loss and trips the circuit breaker to protect the circuit. Since the opening / closing mechanism 5 is not a main part of the present invention, the illustration is also simplified, and a detailed description of the configuration is omitted.

Next, the thermal tripping device 8 will be described with reference to FIG.
Corresponding to each phase of the main circuit of the three-phase circuit breaker, three thermodynamic elements 9 that generate heat and bend according to the energization current are provided in the middle of each electric circuit of the main circuit.
The thermodynamic element 9 is a bimetal 9a formed in a rectangular plate shape, and a belt-like heater 9b is spirally wound through an insulating material. One end of the heater 9b is welded to the bimetal 9a. It is fixed. The three thermoelements 9 are arranged substantially in parallel with the plane sides facing each other, one end side is fixed to a conductor connected to the electric circuit, the other end side is a free end, and the bimetal 9a is heated. It is deformed in the thickness direction and the free end side is bent in the same direction. This free end side is the operating end.

A first interlocking plate 10 and a second interlocking plate 11 are provided at the operating end of the thermal element 9 so as to come into contact with both sides of the plate thickness.
The first interlocking plate 10 and the second interlocking plate 11 are made of a thin insulating material, and have three contact portions 10a and 11a that protrude so as to be substantially E-shaped in plan view. The contact portion 10a of the first interlocking plate 10 is contacted from one of the thermal elements 9 (left in the case of FIG. 2), and the contact portion 11a of the second interlocking plate 11 is the other (right in the case of FIG. 2). ) So as to sandwich the operating end from both sides. Both interlocking plates 10 and 11 are guided by guide portions (not shown) so as to be movable along the displacement direction of the thermal element 9.
A phase missing cam 12 is provided across the two interlocking plates 10 and 11, and the phase missing cam 12 is swingable on the two interlocking plates 10 and 11 by one engaging portion 12 a (see FIG. 4). It is connected to. Further, the phase loss cam 12 has a protruding portion 12b that can come into contact with a transmission piece 13 to be described later.

  With such a configuration, the displacement amount of the thermal element 9 in any one of the three phases becomes smaller than the displacement amount of the other thermal element 9 in the case of a phase failure or the like. A difference occurs in the amount of displacement from the second interlocking plate 11, and the phase loss cam 12 swings at an angle corresponding to this difference, thereby operating a tripping lever 14 (to be described later) via the transmission piece 13 to cut off the circuit. To do. On the other hand, when overloaded, the first interlocking plate 10 is displaced by a predetermined amount, and the trip lever 14 is similarly operated via the open phase cam 12 and the transmission piece 13 to interrupt the circuit.

On the insulated case 1 side of the circuit breaker, as a thermal adjustable part, an adjustment dial 15 for setting the current of the thermal tripping device 8 in accordance with the load capacity (rated current value), and a shaft part of the adjustment dial And an adjustment plate 16 which is moved by being pushed by a cam 15a. The movement of the adjustment plate 16 is transmitted to the trip lever 14 that is pivotally supported by the slider of the thermal adjustable portion. The tripping lever 14 is formed in a U-shape and is capable of pressing the trip lever 17 on the tip side opposite to the shaft support side. It also serves as a bimetal for ambient temperature compensation.
The transmission piece 13 described above is rotatably provided with one end pivotally supported on the housing side between the phase loss cam 12 and the trip lever 14, and the movement of the phase loss cam 12 is tripped lever 14. To communicate to.
In the present application, the portion including the thermal element 9, the first and second connecting plates 10, 11, the open phase cam 12, and the transmission piece 13 is referred to as a thermal trip device 8.

Next, the operation of the circuit breaker will be described with reference to FIG.
The movable contact 18 of the main circuit is disposed at the lower center of the insulating housing 1 so as to face the fixed contact 19, and contacts and separates at the contact portion 20. When the circuit breaker is ON, the current is supplied from the power supply side terminal 3 to the contact portion 20, the movable contact 18, the contact portion 20, the heater 9b of the thermal element 9, the bimetal 9a, and the coil of the overload trip device 7. , Flows to the load side terminal 4.
By rotating the adjustment dial 15 and adjusting it to a predetermined position on the adjustment scale printed on the housing cover 2, the cam portion 15 a rotates and the tripping lever 14 moves through the adjustment plate 16. Thereby, the distance between the head of the trip lever 14 and the open phase cam 12 is adjusted in accordance with the rated current.

When the circuit current exceeds the rated current value of the circuit breaker during use, the bimetal 9a of the thermal element 9 gradually moves on the paper surface of FIG. 2 due to the heat generated by the heater 9b or the heat generated by the bimetal 9a itself. Curve to the left. The phase loss cam 12 also moves to the left via the interlocking plates 10 and 11 pushed by the thermal element 9.
When the overcurrent exceeds the standard value, the transmission piece 13 is pushed by the projection 12b of the phase loss cam 12, and the head of the tripping lever 14 is pushed by this force, so that the tripping lever 14 is pivotally supported. Is pivoted counterclockwise in FIG. 3, and the trip lever 17 is pressed on the tip side of the tripping lever 14. As a result, the opening / closing mechanism 5 operates to shut off the circuit.

Next, a manufacturing method of the thermal tripping device 8 which is a characteristic part of the present invention will be described.
When the thermal tripping device 8 is incorporated in the insulating casing 1 of the circuit breaker, the mounting positions of the three-phase thermal elements 9 and the dimensions between them are as designed due to manufacturing variations and assembly variations. The case where it does not become occurs. FIG. 1 is a plan view schematically showing the interlocking plate portion of the thermal tripping device 8. Hereinafter, a description will be given with reference to FIG. A description will be given of a case where the dimension between the thermodynamic elements 9 is not as designed, and the intermediate phase is shifted to the right side in the drawing as shown in FIG. 1A, for example. That is, it is a case where d1> d2. In this state, even if it tries to match the interlocking plates 10 and 11 manufactured according to the design value, the contact part does not match, so if it is forced to fit, the bimetal 9a part of the thermal element 9 is bent and corrected. It will be. This results in deterioration of the operating characteristics of the circuit breaker.

  Therefore, in the present invention, the measuring device is used to insulate the insulating casing 1 in a state where the three-phase thermal element 9 is assembled to the insulating casing 1 of the circuit breaker in which the thermal tripping device is incorporated and the interlocking plate is not combined. The actual position of the thermal element 9 is measured with reference to. And the difference with respect to a design value is calculated, the dimension of the contact direction of the contact part of both the interlocking plates 10 and 11 is correct | amended with the said difference, Based on the correction value, the interlocking plate was processed individually and processed. The interlocking plate is assembled to the thermal element 9. In the case of FIG. 1A, the dimension a is made shorter than the design value and the dimension b is made longer than the design value is assembled.

Furthermore, it demonstrates concretely. With the three-phase thermal element 9 attached to the insulating housing 1, it is placed at a predetermined position of a measuring device (not shown). In the measuring device, for example, the position of the operating end side of the thermal element 9 with respect to the workpiece is measured with a dial gauge or the like, and the difference from the design value is obtained.
On the other hand, in the interlocking plate processing apparatus (not shown), for example, a half-processed product of the interlocking plate as shown by a broken line in FIG. 1B is set. In the semi-processed product, the length C of the interlocking plate in the direction of contacting the thermal element 9 is longer than the design value. And according to the difference with the design value measured with the measuring device, lengths c1, c2, and c3 in the direction in which each interlocking plate abuts are calculated individually, and according to the calculated length, each interlocking plate 10, 11 is calculated. The abutting portion side tip e of each phase is cut, and the lengthwise end portion f of the entire interlocking plate is also cut to manufacture the interlocking plates 10 and 11.

The above series of operations can be carried out by automating the device, and can be applied in a short time to a thermal trip device incorporated in each circuit breaker.
By mounting the manufactured interlocking plates 10 and 11 in combination with the thermal element 9, the thermal trip device 8 having the interlocking plates 10 and 11 fitted with the thermal element 9 with almost no gap is obtained.
As a result, even when the arrangement position of the thermal element 9 varies due to manufacturing or assembly, the interlocking plates 10 and 11 can be brought into contact with no gap. As compared with the case where the position of the bimetal 9a is adjusted after that, the fluctuation of the contact resistance due to the position adjustment of the bimetal 9a which is an energization circuit and the fluctuation of the bending characteristic of the bimetal 9a can be prevented, and the blocking performance can be improved. Also, the assembly workability is improved.
Therefore, the circuit breaker using the thermal tripping device manufactured by this method is a circuit breaker having excellent operation accuracy when interrupted by an overcurrent.

  In the position measurement of the thermal element 9 described above, the measurement may be performed in a state where the thermal element 9 is bent by applying a force during actual operation in the bending direction of the thermal element 9. By this method, the position of the thermal element 9 in a state closer to actual operation can be measured, and the interlocking plates 10 and 11 can be manufactured according to the position. As a result, when the thermal element 9 is bent by energization, the interlocking plates 10 and 11 come into contact with each other without any gap, so that the operation accuracy at the time of interruption can be improved.

In the manufacturing process of the interlocking plate described above, the cutting process of the thermal element is performed by, for example, pre-processing. In this case, the shape of the cut part can be freely changed by simply changing the mold, so the contact surface of the interlocking plate with the thermal element is not a straight line, but is processed into an arc that protrudes toward the thermal element. May be. Then, when the bimetal is bent by energization, the contact with the interlocking plate becomes a point contact, and the operation of the phase loss cam via the interlocking plate becomes more stable. As a result, the variation in blocking performance can be further reduced.
In addition, although the measurement with the measuring device has been described with a dial gauge, an optical sensor may be used.

  As described above, according to the manufacturing method of the thermal tripping device of the first embodiment, a plurality of thermal elements arranged substantially in parallel with the direction in which the curve is displaced by energization heating being aligned, and the thermal element A first interlocking plate that is disposed on both sides of the operation end and has a contact portion that contacts one surface of the operation end, and a second interlocking plate that has a contact portion that contacts the other surface; Manufacture of a thermal trip device having an open phase cam that is swingably connected across both interlocking plates, and a transmission piece that transmits the displacement of the open phase cam to the open / close mechanism of the circuit breaker This method measures the mounting dimensions of a thermal element with a measuring device in a state in which a plurality of thermal elements are attached to an insulating housing that incorporates a thermal tripping device, and calculates the difference from the design value. In the apparatus, based on the difference information, the dimensions of the contact portions of the first interlocking plate and the second interlocking plate are determined. Correctly processed and assembled both interlocking plates into the thermal element, so that the contact area between the thermal element and the interlocking plate can be assembled almost without any gap, so Assembling accuracy of the interlocking plate due to the variation in the mounting position is improved, and as a result, the variation in the interruption operation due to the displacement of the thermal element due to energization is reduced, and the operation accuracy at the time of interruption due to overcurrent can be improved.

  In addition, the force applied to the thermal element during actual operation was measured in the bending direction during measurement, and each interlocking plate was processed. The operation accuracy at the time of interruption can be improved by contacting each interlocking plate.

  In addition, since the contact part of each interlocking plate is processed into an arc shape that protrudes toward the thermal element side, the contact with the thermal element becomes a point contact, and the operation of the phase loss cam via the interlocking plate is more stable. In addition, the variation in the cutoff performance can be further reduced.

  Furthermore, according to the circuit breaker of the first embodiment, an insulating housing, a fixed contact mounted on the insulating housing, a movable contact installed facing the fixed contact, and a movable contact are provided. An opening / closing mechanism for opening / closing operation, and a thermal tripping device for operating the opening / closing mechanism in response to an overcurrent at the time of energization. The thermal tripping device is a thermal type manufactured by the above manufacturing method. Since the tripping device is used, the assembly accuracy of the thermal element and the interlocking plate is improved, and a circuit breaker having excellent operation accuracy when interrupted by an overcurrent can be obtained.

DESCRIPTION OF SYMBOLS 1 Insulation housing | casing 2 Housing | casing cover 3 Power supply side terminal 4 Load side terminal 5 Opening and closing mechanism part 6 Handle 7 Overload trip device 8 Thermal trip device 9 Thermal element 9a Bimetal 9b Heater 10 First interlocking plate 10a , 11a Contact portion 11 Second interlocking plate 12 Phase loss cam 12a Engagement portion 12b Protrusion portion 13 Transmission piece 14 Trip lever 15 Adjustment dial 15a Cam portion 16 Adjustment plate 17 Trip lever 18 Movable contact 19 Fixed contact 20 Contact part.

Claims (4)

A plurality of thermodynamic elements arranged substantially in parallel with the direction of bending displacement by energization heating, and disposed on both sides of the operation end of the thermodynamic element, and one surface of the operation end A first interlocking plate having an abutting portion that abuts, a second interlocking plate having an abutting portion in contact with the other surface, and both interlocking plates of the first interlocking plate and the second interlocking plate. A manufacturing method of a thermal trip device comprising: an open phase cam that is swingably connected across a transmission piece; and a transmission piece that transmits a displacement of the open phase cam to an opening / closing mechanism of a circuit breaker. ,
The plurality of thermal elements are attached to an insulating casing in which the thermal tripping device is incorporated, and the mounting dimensions of the thermal element are measured by a measuring device in a state before the two interlocking plates are incorporated. Find the difference between
In the processing apparatus for processing both the interlocking plates , based on the difference information, correct the dimensions of the contact portions of the first interlocking plate and the second interlocking plate,
A method for manufacturing a thermal tripping device, wherein both the processed interlocking plates are incorporated into the thermal element. 2. The method of manufacturing a thermal tripping device according to claim 1, wherein when the thermal element is measured, a force applied to the thermal element during actual operation is measured in a bending direction to measure both interlocking plates. A method of manufacturing a thermal trip device characterized by the above. 2. The thermal tripping device manufacturing method according to claim 1, wherein the contact portions of the two interlocking plates are processed into an arc shape projecting toward the thermal element side. A method of manufacturing the removal device. An insulating housing; a fixed contact mounted on the insulating housing; a movable contact installed opposite to the fixed contact; an opening / closing mechanism that opens and closes the movable contact; A thermal trip device that operates the open / close mechanism in response to an overcurrent;
The circuit breaker characterized by using the thermal trip apparatus manufactured by the manufacturing method of Claim 1 or Claim 2 as the said thermal trip apparatus.

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