JP3937655B2 - Method of manufacturing a thermal overload / break-off trip device for circuit breakers - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a bimetal type thermal overload and phase loss trip device incorporated in a circuit breaker that performs overcurrent protection and phase loss protection for motors and the like for circuit breakers and magnetic contactors. About.
[0002]
[Prior art]
First, as a conventional example of a bimetal thermal overload and phase loss tripping device, the overall configuration of a thermal relay applied to an electromagnetic contactor (for three phases) and the structure of its main part are shown in FIGS. Show. In FIG. 3, 1 is a resin case of a relay, 2 is a bimetal 3u, 3v, 3w corresponding to each phase of U, V, and W, and a heater 4 that is wound around the bimetal of each phase and passes a main circuit current. The heat element unit 5 includes a differential shifter mechanism that follows the bending displacement of the bimetal, 6 a contact mechanism, and 7 a reversing spring mechanism that opens and closes the contact mechanism 6 in conjunction with the differential shifter mechanism 5.
[0003]
Here, the bimetals 3 u, 3 v, 3 w of each phase are arranged at equal intervals in the left and right rows, and one end (the upper end in the drawing) is fixedly supported by the resin case 1 via the support fitting 8. On the other hand, as shown in FIG. 4, the differential shifter mechanism 5 includes a first shifter (push shifter) 5I, a second shifter (pull shifter) 5II, and shifters 5I and 5II laid on both sides of the bimetal row. Between the first shifter 5I and the second shifter 5II, and the working ends of the bimetals 3u, 3v, 3w of the respective phases. The arm portions 5a and 5b branch to the side so as to face each other with the leading end portion 3a sandwiched from the left and right.
[0004]
The operation of such an overcurrent / open-phase trip device is well known. When an overload current flows in the main circuit, the first shifter 5I is pushed by the bending displacement of the bimetals 3u, 3v, 3w due to the heat generated by the heater 4, thereby triggering The lever 5III reverses the reversing spring mechanism 7 of FIG. 3 to switch the contact of the contact mechanism 6. In addition, when phase loss occurs, the first shifter 5I is pushed forward while the bimetal of the phase where phase loss has occurred (no bending displacement) restrains the second shifter 5II at the standby position. As a result, the trigger lever 5III swings counterclockwise by the differential between the shifters 5I and 5II, and the same operation as described above is performed.
[0005]
In the thermal overload tripping device incorporated in the circuit breaker for wiring, the main circuit contactor is restrained and held at the closed position by the movement of the differential shifter mechanism driven by the bending displacement of the bimetal described above. The latch receiver of the contact opening / closing mechanism is released, and the main circuit contact is tripped.
[0006]
[Problems to be solved by the invention]
By the way, in the above-described conventional configuration, the bimetal tip 3a and the arm portions of the shifters 5I and 5II in the assembled state in which the bimetals 3u, 3v and 3w of each phase and the differential shifter mechanism 5 are assembled to the resin case 1. If gaps d and e between 5a and 5b remain, bimetal deflection loss occurs, and the amount of bimetal displacement is not accurately transmitted to differential shifter mechanism 5. In addition, if the phase pitch between the bimetals 3u, 3v, and 3w varies due to the mounting orientation (tilt) of the bimetal, assembly errors, etc. during assembly, stable tripping operation characteristics of the circuit breaker cannot be obtained.
[0007]
Therefore, conventionally, in the inspection process after product assembly, the distances a, b, c and the shifters I, II to the tip 3a of the bimetal 3u, 3v, 3w shown in FIG. The gaps d and e between the arm portions 5a and 5b and the bimetal tip 3a are measured. If there is a positional deviation exceeding the allowable range, the above-mentioned distance and gap have a predetermined positional accuracy (for example, ± 0.2 mm). The gap is adjusted by bending the support metal fixture 8 to which the bimetals 3u, 3v, 3w are fixed so as to fit in, or by grinding the end face of the shifter arm portion 5a.
[0008]
However, when the bimetal support metal fitting is bent and corrected, it is difficult to adjust with high accuracy by the springback of the support metal fitting. Further, in order to grind the arm portion of the shifter, it is necessary to move the product from the assembly line to another processing line, and the adjustment work is troublesome.
[0009]
The present invention has been made in view of the above points, and its object is to solve the above-mentioned problems, and to skillfully absorb interphase pitch errors caused by the mounting orientation of each phase, assembly errors, etc. in the product assembly process. It is another object of the present invention to provide a thermal overload / break-off trip device for a circuit breaker which is improved so as to ensure relative positional accuracy between a bimetal / differential shifter mechanism.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, as a means for detecting an overload current and an open phase of a main circuit, a bimetal as a thermal element corresponding to each phase, and a differential shifter mechanism linked to the bimetal are provided. assembled in the unit case, a said differential shifter thermal overload, open-phase tripping device of the circuit breaker which is adapted to tripping the closing contacts of the main circuit by being driven by the operation mechanism, the The differential shifter mechanism is composed of first and second shifters laid on both sides along the bimetal arrangement, and a trigger lever linked between the shifters, and bimetal for each phase. The arm portion branched from the first and second shifters is opposed to each other with the operation end of the first and second shifters opposed to each other, and the differential shifter mechanism is connected to the arm portions of the first shifter and the second shifter. Integrated with a thin connecting part Constituted by the resin molded article to form a punching blade type that divides the connecting portion of the shifter to the tip of the bimetal operating end, assembled the bimetal to the unit case, the differential shifter to said bimetal insert the mechanism from bimetallic tip side in the unit case, to position the differential shifter mechanism at the reference position, by pressing a coupling portion of the shifter in this position to the blade-type bimetal tip, the arm of the first shifter And the arm portion of the second shifter is punched and divided with a blade shape at the tip of the bimetal so that the working end of the bimetal is sandwiched between the arm portion of the first shifter and the arm portion of the second shifter from both the left and right sides. .
[0011]
With this configuration, after assembling each phase bimetal to the unit case in the product assembly process, the differential shifter mechanism (in this state, the first shifter and the second shifter are in an integrated structure) is assembled. The robot is held by a robot or the like and positioned at a predetermined position. When a pressure is applied by applying the shifter to the tip of the bimetal, the arm part is between the first shifter and the second shifter by the bimetal blade shape. It is punched and divided. Moreover, in the assembled state after the division, the ends of the arm portions of the first shifter and the second shifter come into contact with both sides of the bimetal with little play. As a result, interphase pitch errors caused by errors such as the mounting position and posture inclination of each bimetal are absorbed, and stable tripping operation characteristics can be ensured.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on the examples shown in FIGS. In addition, in the figure of an Example, the same code | symbol is attached | subjected to the member corresponding to FIG. 4, and the description is abbreviate | omitted.
[0013]
In other words, in this embodiment, as shown in FIG. 1 (a) or (b), the bimetal 3u, 3v, 3w of each phase has a trapezoidal or V-shaped kerf at the front end (operation end side) 3a. A sharp blade mold 3b is formed. On the other hand, the differential shifter mechanism 5 is a molded product such as phenol resin or epoxy resin. As shown in FIG. 1 (c), the first shifter 5I and the second shifter II are arm portions 5a and 5b corresponding to each phase. Is formed as an integrally molded part connected by a thin connecting portion 5c having a thickness of about 1 mm. In addition, A and B are spindle holes drilled in the left end portions of the first shifter 5I and the second shifter II in order to connect the trigger lever 5III shown in FIG.
[0014]
Next, an assembly procedure for mounting the differential shifter mechanism 5 on the bimetals 3u, 3v, 3w with the blade mold 3b in the product assembly process will be described with reference to FIGS. 2 (a) to 2 (d). First, in the assembly stage in which each component such as the bimetal 3u, 3v, 3w of each phase and the latch receiver 9 linked to the contact opening / closing mechanism of the circuit breaker is assembled to the unit case 1 shown in FIG. 2C, the first shifter 5I and the second shifter 5II of the differential shifter mechanism 5 which are resin integrated molded parts shown in FIG. 2C are held on the handling head (not shown) of the assembly robot. , (b) is positioned and set at a fixed position facing the bimetal tip 3a. This set position is determined by, for example, setting the distance X between the support lever hole A of the trigger lever drilled in the shifter with the latch receiver 9 (already assembled in the unit case) as a reference point. Then, the connecting portion 5c between the arm portions 5a / 5b connecting the first and second shifters 5I and 5II is pressed against the distal end portion 3a of the bimetal 3 from this position. Add
[0015]
Thereby, the thin connecting portion 5c is punched out by the blade mold 3b formed at the tip thereof at the contact position with the bimetal 3u, 3v, 3w, and the arm portion 5a of the first shifter 5I and the arm portion 5b of the second shifter 5II. Is divided. In the assembled state after dividing the connecting portion 5c, the tips of the arm portion 5a of the first shifter 5I and the arm portion 5b of the second shifter 5II are formed as shown in FIGS. 2 (c) and 2 (d). It comes in close contact with the side of 3v, 3w with almost no play gap.
[0016]
Therefore, even if the mounting positions and mounting postures of the bimetals 3u, 3v, and 3w vary in each product at this assembly stage, the variations are absorbed and the first shifter 5I and the second shifter 5II of the differential shifter mechanism 5 are installed. It can be combined at a relatively appropriate position, thereby stabilizing the tripping operation characteristics of the circuit breaker.
[0017]
【The invention's effect】
As described above, according to the present invention, the differential shifter mechanism is constituted by an integrated resin molded product in which the arm portion of the first shifter and the arm portion of the second shifter are connected by a thin connecting portion. A punching blade mold is formed at the tip of the working end of the bimetal , and the bimetal is assembled to the unit case , and the differential shifter mechanism is attached to the bimetal from the tip of the bimetal. is inserted into the unit case, to position the differential shifter mechanism at the reference position, by pressing a coupling portion of the shifter in this position to the blade-type bimetal distal arm portion and the arm of the second shifter of the first shifter Since the bimetal cutting edge is punched and divided between the parts, and the working end of the bimetal is sandwiched between the arm part of the first shifter and the arm part of the second shifter from both the left and right sides. Differential The ends of the arms of the first and second shifters of the lid mechanism come into contact with the side surfaces of the bimetal with almost no play gap. This absorbs errors in the intermetal pitch due to the mounting orientation and assembly errors of the bimetal. The bending displacement of the circuit breaker is accurately transmitted to the shifter without bending loss, and as a result, the tripping operation characteristics of the circuit breaker are stabilized.
[Brief description of the drawings]
FIGS. 1A and 1B are configuration diagrams of main components of an overload and phase loss detection unit according to an embodiment of the present invention, in which FIGS. 1A and 1B are side views of different bimetal embodiments, and FIG. Fig. 2 is a plan view of the mechanism before assembly. Fig. 2 is an explanatory diagram of the assembly process of combining the bimetal and differential shifter of Fig. 1, where (a), (b) and (c), (d) are assembled. Fig. 3 is a plan view showing the state immediately before and after assembly, and a front view. Fig. 3 is an overall configuration diagram of a thermal relay as a conventional example of a thermal overload tripping device. Fig. 4 is a bimetal and differential shifter mechanism. Conventional structure of combined overload and phase loss detector [Explanation of symbols]
2 Heat element parts 3u, 3v, 3w Bimetal 3a Tip part 3b Blade type 5 Differential shifter mechanism 5I First shifter 5II Second shifter 5III Trigger lever 5a, 5b Arm part 5c Connection part

Claims (1)

Overload current of the main circuit, as the detection means of phase failure, the bimetal as thermally activated element corresponding to each phase, and assembling the differential shifter mechanism interlocked with the bimetal unit case, the operation of the differential shifter mechanism A thermal circuit type overload and phase loss trip device for a circuit breaker that is driven to trip the open / close contact of the main circuit, and the differential shifter mechanism is arranged on both sides of the bimetal array. The first and second shifters are laid and trigger levers that are linked and linked between the shifters, and the bimetal working ends are sandwiched from the left and right sides for each phase. In what opposed the arm branched from the shifter of
The differential shifter mechanism, between the arms of the first shifter and the arm portion of the second shifter is constituted by integrated resin molding continuous with the thin coupling portion, of the shifter to the tip of the bimetal operating end forming a punching blade type that divides the connecting part, assembled the bimetal to the unit case, the insert the differential shifter mechanism bimetal tip side in the unit case with respect to the bimetal, the differential The shifter mechanism is positioned at the reference position, and at this position, the shifter connecting portion is pressed against the blade shape at the tip of the bimetal, and the blade shape at the tip of the bimetal is between the arm portion of the first shifter and the arm portion of the second shifter. A thermal overload and phase loss tripping device for a circuit breaker characterized by punching and cutting and sandwiching the working end of the bimetal from the left and right sides between the arm portion of the first shifter and the arm portion of the second shifter Manufacturing method .

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