JP4690472B2 - Thermal trip device and circuit breaker - Google Patents

Description

  The present invention relates to a thermal tripping device used for a circuit breaker, for example.

  A conventional thermal trip device includes a bimetal and an adjuster, and adjusts the distance (gap) to the trip bar by adjusting the fixing position of the adjuster. In the adjuster, the lower hook-shaped portion is engaged with a hole provided in the bimetal, and the upper arcuate portion is fitted into the groove portion at the tip of the bimetal. The adjuster is rotatable with respect to the bimetal around the bowl-shaped portion. In the adjustment step, the position of the adjuster in the rotational direction is adjusted to an appropriate position, and the bimetal and the adjuster are welded and fixed in the groove at the tip of the bimetal so as to maintain the position. Thus, the protrusion amount from the bimetal of the adjuster was adjusted.

JP 2002-260515 A

  However, in the conventional thermal tripping device, the width of the bimetal groove is wider than the thickness of the adjuster so that the adjuster can rotate with respect to the bimetal. If the groove width is narrower, an extremely large load is required to rotate the adjuster, and appropriate adjustment cannot be made.In addition, processing errors are inevitable in the groove width and the thickness of the adjuster. The groove width and adjuster thickness could not be made the same value. Therefore, the groove width of the bimetal groove needs to be set wider than the thickness of the adjuster, and there is always a wide gap between the groove and the adjuster.

  When the bimetal and the adjuster are fixed, it is necessary to instantaneously fix the end face of the groove of the bimetal and the side surface of the adjuster. For example, laser welding is used to fix the bimetal. At this time, since there is a wide gap between the end face of the groove and the side face of the adjuster, there is a problem that poor welding is likely to occur.

  It is an object of the present invention to obtain a thermal tripping device that has high adjustment accuracy between a bimetal and a regulator and that has reduced improper fixing between the bimetal and the regulator.

  The thermal tripping device according to the present invention includes a bimetal heated by an electric current and a regulator that comes into contact with the trip bar due to the curvature of the bimetal. The bimetal has a guide groove that opens at one end on the side that contacts the trip bar, and an engagement hole that is provided on the other end side from the guide groove. The adjuster includes a hook-shaped portion engaged with the engagement hole, an arc-shaped portion that is rotatably inserted into the guide groove, and an abutment that connects the arc-shaped portion and the hook-shaped portion and contacts the trip bar. And a projecting portion provided on the arcuate portion and extending along the arcuate portion and projecting in the thickness direction of the adjuster. The projecting portion is connected to the end portion not connected to the contact portion. Also, it was welded and fixed to the end of the bimetal near the contact part.

  The thermal tripping device according to the present invention can adjust the bimetal and the adjuster with high accuracy, and can reduce improper fixing between the bimetal and the adjuster.

1 is a partially cut front view showing a circuit breaker having a thermal tripping device according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of the thermal tripping device of FIG. FIG. 3 is a front view of the bimetal of FIG. 4 is a perspective view of the regulator of FIG. FIG. 5 is a view for explaining a gap adjusting method of the thermal tripping device of FIG. FIG. 6 is an enlarged view of the upper end portion of the bimetal of FIG. FIG. 7 is a perspective view of a regulator according to Embodiment 2 of the present invention.

Embodiment 1 FIG.
1 is a partially cut front view showing a circuit breaker having a thermal tripping device according to Embodiment 1 of the present invention. An insulating housing 30 of the circuit breaker includes a base 1 and a lid 2 each made of synthetic resin. A power supply terminal 3 for detachably connecting a power supply side electric wire and a load terminal 6 for detachably connecting a load side electric wire are mounted on the base 1. A fixed contact 4 provided with a power terminal 3 at one end is mounted on the base 1. The movable contact 5 that contacts and separates from the fixed contact 4 is connected to a thermal tripping device 13 that operates the opening / closing mechanism 9 in response to an overcurrent. A bimetal 11 is fixed by a rivet 14 to a heating element 7 provided with a load terminal 6 at one end.

  The thermal tripping device 13 includes a heating element 7, a bimetal 11 fixed to the heating element 7 with a rivet 14, and a regulator 12. The opening / closing mechanism 9 that opens and closes the movable contact 5 with respect to the fixed contact 4 has a trip bar 8, and operates when the trip bar 8 is pushed by a thermal tripping device 13. The operation when an overcurrent exceeding the rated current flows will be described below.

  When an overcurrent flows through the heating element 7 or the bimetal 11, the temperature of the heating element 7 and the bimetal 11 rises. The bimetal 11 bends as the temperature of the bimetal 11 increases. The bending amount of the bimetal 11 increases, the adjuster 12 comes into contact with the trip bar 8, and the bending amount of the bimetal 11 further increases, so that the thermal tripping device 13 pushes the trip bar 8. When the trip bar 8 is pushed by the thermal tripping device 13, the opening / closing mechanism 9 is actuated, and the movable contact 5 is instantaneously dissociated from the fixed contact 4 and the electric circuit from the power supply terminal 3 to the load terminal 6 is interrupted. Do (trip).

  The range of operating characteristics (tripping characteristics) when an overcurrent flows is defined by standards such as JIS, and products must satisfy this range. However, the operating point of the tripping mechanism, that is, the position where the bimetal 11 pushes the trip bar 8 is the processing / assembly error of each part constituting the thermal tripping device 13 and the opening / closing mechanism 9, variation in material characteristics, etc. The trip characteristics vary due to the accumulation of manufacturing variations, resulting in variations in trip characteristics. Therefore, in order to absorb such manufacturing variations, the adjuster 12 is combined with the bimetal 11 which is a component of the thermal tripping device 13, and the positions of the bimetal 11 and the adjuster 12 are adjusted and inspected in the assembly process. It is carried out.

  The thermal tripping device 13 will be described in detail. 2 is a perspective view of a thermal tripping device, FIG. 3 is a front view of a bimetal, and FIG. 4 is a perspective view of a regulator. The bimetal 11 is formed in a rectangular shape by punching a plate-like bimetal member, and a guide groove 11a is formed at one end of the side that comes into contact with the trip bar 8, and the guide groove 11a extends from the guide groove 11a to the other end in the longitudinal direction. Engagement holes 11b are formed at a predetermined interval. A mounting hole 11c is provided on the other end side.

  The adjuster 12 is formed by punching a metal plate-like member and performing a forming process. The adjuster 12 has a hook-like portion 12a that can be engaged with the engagement hole 11b of the bimetal 11 on one end side, and is inserted into the guide groove 11a. An arcuate portion 12c is formed on the other end side. The arcuate part 12c fits into the guide groove 11a even if it rotates around the flanged part 12a. A protrusion 12b for restricting rotation is formed at the end of the arcuate portion 12c.

  The arcuate portion 12c has a projecting portion 12e bent by, for example, molding processing on the outer periphery thereof, and has an arc shape centered on the flange-shaped portion 12a. The adjuster 12 and the trip bar 8 come into contact with each other at a contact portion 12d formed so as to connect the flange portion 12a and the arcuate portion 12c. The protruding portion 12e protrudes in the axial direction of the rotating shaft around which the adjuster 12 rotates, that is, protrudes in the thickness direction of the adjuster 12, and is an arc centered on the hook-shaped portion 12a along the arcuate portion 12c. It is stretched so as to have a shape.

  The adjuster 12 is assembled to the bimetal 11, and the bimetal 11 is fixed to the heating element 7 with the rivets 14 through the mounting holes 11 c. In addition, the shape of the contact part 12d of an Example is an example, and the shape of the contact part 12d can be suitably changed according to the motion and cross-sectional shape of the trip bar 8. FIG.

  Next, a method for assembling and adjusting the thermal tripping device 13 will be described. FIG. 5 is an enlarged view of the upper end portion of the bimetal 11, and FIG. 6 is a view for explaining a method of adjusting the gap between the thermal tripping device 13 and the trip bar 8.

  First, the bimetal 11 fixed to the heating element 7, the power supply terminal 3, the fixed contact 4, the movable contact 5, the opening / closing mechanism 9, and the load terminal 6 are incorporated into the base 1. The adjuster 12 is assembled to the bimetal 11 incorporated in the base 1. The hook-like portion 12 a of the adjuster 12 is engaged with the engagement hole 11 b of the bimetal 11, and at the same time, the arcuate portion 12 c is fitted into the guide groove 11 a of the bimetal 11. As shown in FIG. 6A, when the adjuster 12 is engaged with the bimetal 11, the adjuster 12 falls to the abutting portion 12d side, and the protruding portion 12b is regulated by the bimetal 11, so that the posture of the adjuster 12 is changed. It will be held. This is because the center of gravity of the adjuster 12 is close to the contact portion.

  As shown in FIG. 5, when the adjuster 12 is engaged with the bimetal 11, the projecting portion 12e comes into contact with the upper end portion of the bimetal 11, and the shape of the upper end side of the bimetal 11 in the projecting portion 12e is centered on the hook-shaped portion 12a. Therefore, even when the adjuster 12 is rotated, the state where it is always in contact with the upper end portion of the bimetal 11 is maintained. Therefore, the gap 22 between the welded portion of the protruding portion 12e and the upper end portion of the bimetal 11 can be made as small as possible.

  When the bimetal 11 is bent to adjust the fixing position between the adjuster 12 and the bimetal 11, the surface of the protruding portion 12 e facing the upper end of the bimetal 11 is a contact surface that is always in contact with the upper end of the bimetal 11. . When the bimetal 11 is curved, the arc shape drawn by the upper end portion of the bimetal 11 and the arc shape of the contact surface of the adjuster 12 are substantially matched, so that the gap between the welded portion of the protruding portion 12e and the upper end of the bimetal 11 is set. 22 can be almost eliminated.

  Next, the trip bar 8 is held by a holder (not shown) so that the trip bar 8 incorporated in the base 1 does not move. A current having a predetermined current value is passed through the bimetal 11 to bend the bimetal 11. When the bimetal 11 is curved as shown in FIG. 6B, the contact portion 12 d of the adjuster 12 eventually comes into contact with the trip bar 8. When the bimetal 11 is further bent by energization as shown in FIG. 6C, the adjuster 12 is regulated by contacting the trip bar 8, so that the protruding amount from the bimetal 11 is reduced, that is, the bimetal 11. The bimetal 11 is rotated in the direction opposite to the bending direction.

  The energization is continued as it is, and the bimetal 11 and the adjuster 12 are fixed by welding at the moment when a predetermined energization time or bending amount is reached. Since the amount of bending of the bimetal increases for a while after the energization is stopped, the bimetal 11 and the adjuster 12 need to be fixed instantaneously, and welding is desirable as a fixing method. For example, fixing is performed using laser welding to complete the adjustment. Welding is penetration welding in which a laser is irradiated from above the protruding portion 12 e to penetrate the protruding portion 12 e of the adjuster 12 and weld to the bimetal 11.

  Note that the predetermined current value and the predetermined energization time are a current value and an energization time for causing the circuit breaker to trip within a range defined by a standard such as JIS. When the predetermined current value and the predetermined energization time are selected as the current value and the energization time that are substantially in the center of the standard range, defects outside the standard range can be reduced in the inspection process for inspecting that the standard such as JIS is satisfied. . In many cases, in order to complete the gap adjustment of the circuit breaker in a short time, the adjustment is performed by flowing a current having a current value larger than the current value defined in the standard for a time shorter than the time defined in the standard. Further, since the bending amount of the bimetal 11 is determined by the current value of the current and the energization time, even if the bimetal 11 and the regulator 12 are fixed by welding at the moment when the predetermined bending amount based on the predetermined energization time is reached, The positions of the bimetal 11 and the adjuster 12 can be adjusted.

  The method of bending the bimetal 11 by energization and welding and fixing the adjuster 12 and the bimetal 11 when a predetermined energization time is reached is the same as the method disclosed in JP-A-2002-260515.

  In the first embodiment, since the gap 22 between the welded portion of the protrusion 12e of the adjuster 12 and the upper end of the bimetal 11 is made as small as possible or almost eliminated, poor welding between the bimetal 11 and the adjuster 12 is reduced. Can be made.

  In the case of through welding, a laser must be irradiated to the position where the bimetal 11 and the adjuster 12 overlap. The alignment of the laser needs to match the two directions of the bending direction of the bimetal 11 and the axial direction of the rotation axis of the adjuster 12 orthogonal to the bimetal 11. Since the bimetal 11 is curved when adjusting the fixing position between the adjuster 12 and the bimetal 11, the position of the upper end of the curved bimetal 11 is grasped by a sensor, and a laser is irradiated within the thickness of the bimetal 11. In other words, the irradiation position in the bending direction is required to be positioned with relatively high accuracy.

  Although it is necessary to match the irradiation position of the adjuster 12 in the rotation axis direction, welding can be performed if the overlapping portion where the protruding portion 12e of the adjuster 12 overlaps the upper end portion of the bimetal 11 is irradiated with laser. Since the protrusion length in the protrusion 12e of the adjuster 12, that is, the protrusion length in the rotation axis direction, is longer than the plate thickness of the adjuster 12 and the plate thickness of the bimetal 11, the laser alignment is relatively long. The laser beam may be irradiated within the range of the portion, and the irradiation position in the rotation axis direction may have a relatively low accuracy.

  On the other hand, since the conventional thermal tripping device has to butt-weld the bimetal 11 and the adjuster 12, the laser alignment is performed not only in the bending direction of the bimetal 11 but also the rotation axis of the adjuster 12. It is required to carry out with high precision also in the direction.

  Therefore, the thermal tripping device according to the first embodiment can facilitate the alignment of the laser as compared with the conventional one. In addition, since the laser irradiable range is wide, welding between the bimetal 11 and the adjuster 12 can be appropriately performed, and welding failure between the bimetal 11 and the adjuster 12 can be reduced.

  In the first embodiment, since the protruding portion 12e is through-welded, there is no problem even if a wide gap is formed between the arcuate portion 12c of the adjuster 12 and the guide groove 11a of the bimetal 11 as shown in FIG. By making the groove width of the guide groove 11a sufficiently wider than the thickness of the arcuate portion 12c, the gap 21 becomes wider, and the friction generated between the groove side surface of the guide groove 11a and the arcuate portion 12c can be made extremely small. For this reason, when adjusting the position of the bimetal 11 and the adjuster 12, an unnecessary load is not added to the bimetal 11, and adjustment accuracy can be improved.

  In order to reduce poor welding between the bimetal 11 and the adjuster 12, it is necessary to make the gap 22 between the welded portion of the protruding portion 12e and the upper end of the bimetal 11 as narrow as possible, and preferably eliminate almost all of them. When the fixing position of the adjuster 12 and the bimetal 11 is adjusted by curving the bimetal 11, the protruding portion 12 e of the adjuster 12 is always in contact with the upper end of the bimetal 11. It will occur. However, only the weight of the adjuster 12 acts here, and the adjuster 12 is extremely light, so that the generated frictional force is extremely small and can be ignored.

  Therefore, when the bimetal 12 is curved and the fixing position with the adjuster 12 is adjusted, the contact surface of the protruding portion 12e of the adjuster 12 rotates while contacting the upper end of the bimetal 11, and the frictional force due to the contact Is extremely small, the position adjustment between the bimetal 11 and the adjuster 12 can be performed with high accuracy.

  In the circuit breaker of the first embodiment, since the thermal tripping device 13 can adjust the bimetal 11 and the regulator 12 with high accuracy, the gap adjustment between the trip bar 8 and the thermal tripping device 13 can be made high. Can be accurate. Therefore, the tripping characteristics of the circuit breakers can be stabilized, and the tripping characteristics between the circuit breakers can be made uniform. Further, the circuit breaker according to the first embodiment can reduce defective products because the thermal tripping device 13 can reduce defective fixing between the bimetal 11 and the regulator 12.

  As described above, according to the thermal tripping device 13 according to the first embodiment of the present invention, the bimetal 11 has the guide groove 11a and the engagement hole 11b opened at one end on the side in contact with the trip bar 8. The adjuster 12 connects the hook-shaped portion 12a engaged with the engagement hole 11b, the arc-shaped portion 12c inserted into the guide groove 11a so as to be rotatable, and the bow-shaped portion 12c and the hook-shaped portion 12a. A contact portion 12d that contacts the trip bar 8, and a projecting portion 12e that is provided on the arcuate portion 12c and that extends along the arcuate portion 12c and projects in the thickness direction of the adjuster 12. Since the protruding portion 12e is welded and fixed to the end of the bimetal 11 closer to the abutting portion 12d than to the end on the side not connected to the abutting portion 12d, the bimetal 11 is different from the conventional one in which fixing failure is likely to occur. And adjuster 12 can be adjusted with high accuracy. It is possible to reduce the fixing failure between the bimetal 11 and the coordinator 12.

  According to the circuit breaker according to the first embodiment of the present invention, the thermal tripping device 13 has the guide groove 11a and the engagement hole 11b opened at one end on the side where the bimetal 11 contacts the trip bar 8. The adjuster 12 connects the hook-shaped portion 12a engaged with the engagement hole 11b, the arc-shaped portion 12c inserted into the guide groove 11a so as to be rotatable, and the bow-shaped portion 12c and the hook-shaped portion 12a. A contact portion 12d that contacts the trip bar 8, and a projecting portion 12e that is provided on the arcuate portion 12c and that extends along the arcuate portion 12c and projects in the thickness direction of the adjuster 12. Since the protruding portion 12e is welded and fixed to the end portion of the bimetal 11 closer to the abutting portion 12d than to the end portion not connected to the abutting portion 12d, the gap adjustment between the trip bar 8 and the thermal trip device 13 is adjusted. With high accuracy and stable tripping characteristics Is to be able, it is possible to reduce product defects.

Embodiment 2. FIG.
FIG. 7 is a perspective view of a regulator according to Embodiment 2 of the present invention. It differs from the adjuster 12 of the first embodiment in that the protruding portion 12e is provided in addition to the arcuate portion 12c. The protrusion 12e was formed by bending. Since the rigidity of the adjuster 12 is improved by widening the extending range of the protrusion 12e, the adjuster can be prevented from being deformed during handling.

  Note that the protrusion provided other than the arcuate part 12c may not have the same protrusion length as the protrusion 12e provided with the arcuate part 12c. Further, the protrusion provided other than the arcuate part 12c does not need to be continuous with the protrusion 12e provided with the arcuate part 12c, and may be provided separately. By separating the projecting portion 12e of the arcuate portion 12c from the other projecting portions, the shape of the projecting portion other than the projecting portion 12e can be made independent, and the arc shape of the projecting portion 12e of the arcuate portion 12c can be made with high accuracy. Can be formed.

  In the first and second embodiments, the protrusion 12e of the adjuster 12 is described as being formed by bending. However, the protrusion 12e is formed by fixing the protrusion 12e by welding, or the adjuster 12 is integrally formed by casting. You can do it. Further, the protruding portion 12e may be provided on the side surface of the adjuster 12.

  Further, the example in which the protrusion 12b that restricts the rotation of the adjuster 12 when the adjuster 12 is engaged with the bimetal 11 has been described in the arcuate portion 12c, but the rotation of the adjuster 12 is restricted. The protruding portion may be provided on the protruding portion 12e.

  Since the thermal tripping device according to the present invention can adjust the gap with the trip bar with high accuracy and can reduce improper fixing between the bimetal and the adjuster, it can be used as a circuit breaker having an electric circuit switching mechanism. It can be suitably applied.

DESCRIPTION OF SYMBOLS 1 Base 2 Lid 4 Fixed contact 5 Movable contact 8 Trip bar 9 Opening / closing mechanism 11 Bimetal 11a Guide groove 11b Engagement hole 12 Adjuster 12a Riddle part 12c Arcuate part 12d Contact part 12e Protrusion part 13 Thermal motion Type tripping device 30 Insulated housing

Claims (5)

A thermal trip device comprising a bimetal heated by an overcurrent and a regulator abutting against the trip bar by the curvature of the bimetal,
The bimetal has a guide groove that opens at one end on the side that contacts the trip bar, and an engagement hole that is provided on the other end side from the guide groove,
The adjuster includes a hook-shaped portion engaged with the engagement hole, an arc-shaped portion that is rotatably inserted into the guide groove, and connects the bow-shaped portion and the hook-shaped portion to the trip bar. An abutting part that abuts on the arcuate part, and a projecting part that extends along the arcuate part and projects in the thickness direction of the adjuster. A thermal trip device that is welded and fixed to the end portion of the bimetal closer to the abutting portion than the end portion on the side not connected to the contact portion.   2. The thermal tripping device according to claim 1, wherein the protruding portion of the adjuster has an arc shape with the bimetallic end portion side of the arcuate portion as a center. .   The protruding portion of the adjuster has a contact surface that rotates while contacting the end portion of the bimetal when the bimetal is bent to adjust the fixing position with the bimetal. Thermal trip device.   The thermal trip device according to any one of claims 1 to 3, wherein the adjuster is provided with a protruding portion protruding in a thickness direction of the adjuster at the contact portion. . An insulating housing composed of a base and a lid, a fixed contact mounted on the base of the insulating housing, a movable contact installed facing the fixed contact, and a trip bar. An open / close mechanism that opens and closes the movable contact with respect to the fixed contact; and a thermal trip device that is connected to the movable contact and operates the open / close mechanism in response to an overcurrent.
5. The circuit breaker according to claim 1, wherein the thermal tripping device is the thermal tripping device according to any one of claims 1 to 4.

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