JP5169721B2 - Circuit breaker - Google Patents

Description

  The present invention relates to a circuit breaker, and more particularly to an overcurrent trip device.

Conventional circuit breakers of low rated current products employ a fully electromagnetic type that is small and relatively easy to manufacture as a method of overcurrent tripping device. The fully electromagnetic overcurrent tripping device has obtained a tripping release characteristic when the moving iron core has a time difference due to the viscosity of the braking oil in the oil dashpot. In addition, when a large current such as a short circuit current is generated, the instantaneous tripping characteristic is obtained by the armature operating instantaneously.

Also in the circuit breaker of a high rated current products, remove the overcurrent devices in some cases relatively manufacture small adopts easy complete electromagnetic. In order to obtain circuit breakers with different rated currents, the number of windings and the viscosity of the brake oil were changed.

JP-A-7-153363 (stages 0002 to 0003, FIGS. 7 and 8)

  However, since the conventional fully electromagnetic circuit breaker has obtained the delayed trip characteristic and the instantaneous trip characteristic only by the electromagnet device, it is difficult to set the instantaneous trip current value high, only the magnitude of the current. Since it was detected and tripped, there was a problem that the circuit breaker could not be tripped as long as the specified current did not flow even when abnormal heat was generated.

  For this reason, the conventional fully electromagnetic circuit breakers are not capable of being tripped accidentally due to an increase in inrush current or causing harmonics due to the spread of recent high-efficiency transformers and DC / AC converters. There was a risk of burning due to heat generation.

  This problem can be solved by adopting a thermal electromagnetic type that can set the instantaneous trip current value high and can be tripped even in the case of abnormal heat generation.

  However, simply applying the thermo-electromagnetic method to a circuit breaker with a low rated current product will make the high resistance heating element long to bend the bimetal at a low current, or to obtain an instantaneous trip characteristic even at a low current. In addition, there are problems that the overcurrent tripping device becomes large by winding dozens of windings of the electromagnet device, and the circuit breaker becomes large.

  An object of the present invention is to obtain a small circuit breaker having a thermal electromagnetic overcurrent tripping device even in a circuit breaker of a low rated current product.

In the circuit breaker according to the present invention, the overcurrent tripping device that operates the switching mechanism in response to an overcurrent is composed of an electromagnet device having a fixed core and a thermal device that operates by heat due to the overcurrent, and the fixed core Has a base mounting portion on the shaft of the fixed core. When the electromagnet device is installed on the base, the fixed iron core is interposed between a mover holder that rotatably holds the movable contactor and an electric circuit member connected to one end of the winding of the electromagnet device. It was tightened with a tightening body that engaged with the mounting portion.

  In the circuit breaker according to the present invention, even in a circuit breaker having a low rated current product, a circuit breaker including a thermal electromagnetic overcurrent tripping device can be configured in a small size.

Embodiment 1 FIG.
1 is a longitudinal sectional view showing a circuit breaker according to Embodiment 1 of the present invention. FIG. 2 is an enlarged view of the overcurrent tripping device connected to the load terminal shown in FIG. 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 25 for detachably connecting a power supply side electric wire and a load terminal 16 for detachably connecting a load side electric wire are mounted on the base 1. A stationary contact 3 having a power terminal 25 at one end is mounted on the base 1. A movable contact 4 that contacts and separates from the fixed contact 3 is connected to an overcurrent tripping device 6 that operates an opening / closing mechanism 9 in response to an overcurrent via a mover holder 5.

  The mover holder 5 holds the movable contact 4 so as to be rotatable. The movable element holder 5 is also a connection terminal member having a connection part (not shown) connected to the movable contact 4 and a connection terminal part 5 a connected to the overcurrent tripping device 6, and the power supply terminal 25. To the overcurrent tripping device 6 is formed. The overcurrent tripping device 6 is also connected to the load terminal 16, and an electric circuit from the power supply terminal 25 to the load terminal 16 is configured.

  An opening / closing mechanism 9 that opens and closes the movable contact 4 with respect to the fixed contact 3 includes a trip bar 9a and the like. The coupling screw 7 electrically connects the connection terminal portion 5 a of the movable element holder 5 and the overcurrent tripping device 6 and is fixed to the base 1 through the joint washer 8. The fixed contact 3, the movable contact 4, the opening / closing mechanism 9, and the overcurrent tripping device 6 are mounted inside the insulating housing 30.

The overcurrent tripping device 6 is roughly divided into a thermal device 6a that operates by heat due to overcurrent and has a time-delayed trip characteristic, and an electromagnet device 6b that has an instantaneous tripping property. The thermal apparatus 6a includes a bimetal 10 that is a thermal element. The bimetal 10 is integrally fixed by a bimetal terminal 11 and a rivet 12 and is fixed to the base 1. A heating element 13 is wound around the bimetal 10 via an insulator 14, one end side is electrically joined to the bimetal 10, and the other end side is connected to the load terminal 16 via a flexible conductor 15. An adjusting screw 17 is attached to the free end of the bimetal 10 and adjusts the time-delaying release characteristic. The adjusting screw 17 is fixed with a set nut 18.

  When an overcurrent occurs, the bimetal 10 is bent by the heat generated by the heating element 13, and the adjusting screw 17 pushes the trip bar 9a to trip the circuit breaker.

  The electromagnet device 6b includes a yoke 19 made of a magnetic material such as an iron plate, an electromagnet device main portion 40 including a winding portion 20, and an armature 24 made of synthetic resin. The electromagnet device main portion 40 is fitted to the yoke 19. The electromagnet device 6b is press-fitted and fixed so that an oval projection 19a provided on the yoke 19 fits into a groove (not shown) provided on the base 1, and is positioned at a predetermined position on the base 1. Is done.

  As shown in FIG. 3, the winding part 20 has a winding 20b wound around a winding frame 20a formed of synthetic resin. FIG. 3 is an assembly view of the main part 40 of the electromagnet device. One end of the winding 20b is joined to the yoke 19, and the other end is joined to the bimetal terminal 11 of the thermal apparatus 6a. A fixed iron core 21 and a movable iron core 22, both of which are made of a magnetic material, are inserted into the hollow holes of the winding frame 20 a, and the movable iron core 22 is urged upward by a push spring 23. The armature 24 is rotatably supported by inserting a snap-fit rotary shaft 24b into a shaft hole 19b provided in the yoke 19. The head portion 22 a of the movable iron core 22 is inserted into the groove portion 24 a of the armature 24.

  When a large current such as a short-circuit current is generated, a magnetic field is generated by the current flowing through the winding portion 20, and the movable iron core 22 is attracted to the fixed iron core 21 side against the push spring 23. Rotates clockwise around the shaft hole 19b of the yoke 19, and trips the circuit breaker by pushing the trip bar 9a.

  Next, the procedure for assembling the electromagnet device 6b will be described with reference to FIGS. FIG. 4 is an assembly view of the electromagnet device 6b. First, as shown in FIG. 3, the movable iron core 22, the push spring 23, and the fixed iron core 21 are sequentially inserted from one direction into the hollow hole of the winding part 20 to assemble the electromagnet device main part 40. Then, immediately as shown in FIG. 4, the electromagnet device main portion 40 is inserted into the arc groove 19c and the long arc groove 19d above and below the yoke 19 and fixedly fitted.

Thereafter, one end of the winding 20 b of the electromagnet device main portion 40 is joined to the yoke 19. Thereby, the winding 20b and the yoke 19 are integrated as an electromagnet device 6b are electrically connected, the electromagnetic device main portion 40 is fastened securely entirely from the yoke 19. The other end of the winding 20b of the electromagnet device main portion 40 is joined to the bimetal terminal 11 of the thermal actuator 6a. As a result, the electromagnet device 6b and the thermal device 6a are combined and integrated as an overcurrent tripping device 6.

  The shaft of the fixed iron core 21 of the electromagnet device 6b is provided with a female screw portion 21a that is a base mounting portion. A through hole provided in the connection terminal portion 5 a of the movable element holder 5 is overlapped with the through hole of the joint washer 8 fitted to the base 1. The overcurrent tripping device 6 is inserted into the place where these through holes are overlapped, and then tightened and fixed by a coupling screw 7 which is a tightening body and is screwed into the female screw portion 21a. When the electromagnet device 6 b is installed on the base 1, the yoke 19 and the connection terminal portion 5 a of the mover holder 5 are in direct pressure contact, and the mover holder 5 is electrically connected to the yoke 19. .

  The joint washer 8 is disclosed in, for example, Japanese Patent No. 3841987. The joint washer 8 is formed of, for example, an elastic iron plate, a base portion that comes into contact with the movable element holder 5, a pair of leg portions bent substantially at right angles from both ends of the base portion, and a tip end of the leg portion A pair of elastic claws bent in a hook shape from the portion are formed. A joining hole for fitting the joining washer 8 is formed in the bottom of the base 1, and a locking part for locking a pair of elastic claws is formed in the joining hole. Since the engaging portion provided on the base 1 is elastically clamped by the pair of elastic claws having the elasticity of the joint washer 8, the female screw portion 21 a of the fixed iron core 21 can be firmly fixed to the base 1.

  In the circuit breaker according to the first embodiment, the yoke 19 serves as an electric circuit member that connects the winding 20b and the connection terminal portion 5a of the mover holding body 5, so that the mover holding body 5 and the winding 20b are connected. There is no need to prepare a separate relay member for relaying. Therefore, in the circuit breaker of the first embodiment, the height of the electromagnet device 6b and the height of the overcurrent tripping device 6 do not extend upward in the base 1 due to the increase in the thickness of the relay member. A marginal space can be generated in the vertical direction of the circuit breaker. By installing the overcurrent tripping device 6 close to the bottom of the base 1 so as to eliminate this marginal space, the thickness of the circuit breaker in the vertical direction can be reduced and the size can be reduced.

  In a circuit breaker of a low rated current product, the height of the winding part 20 can be configured to be high by utilizing a margin space created in the vertical direction of the circuit breaker. Thereby, a necessary ampere turn can be secured, and the thickness of the circuit breaker in the vertical direction is not increased. Therefore, even a circuit breaker with a low rated current product can be made compact.

In a circuit breaker of low rated current product, when the ampere turn of the winding 20b is small, the electromagnetic force is small, so the load of the push spring 23 must be reduced to move the electromagnet device 6b, and the trip The instantaneous tripping characteristic is not stable by losing the load of the bar 9a. Unlike this, the circuit breaker of the first embodiment can increase the ampere turn of the winding 20b, so that the electromagnetic force increases and the instantaneous trip characteristic can be stabilized.

  In addition, a female screw portion 21a is provided on the shaft of the fixed iron core 21 of the electromagnet device 6b, and the coupling screw 7 is screwed into the female screw portion 21a to electrically connect the yoke 19 and the mover holder 5. A connecting place for connecting the relay member connected to the wire 20b and the mover holder 5 is provided on the outer peripheral portion of the arrangement region of the overcurrent tripping device 6 on the base 1 so that the relay member and the mover holder 5 are connected. Are electrically connected to each other and may not be fixed to the base 1. Therefore, a marginal space can be generated in the power load direction in the circuit breaker, that is, in the direction of the power terminal 25 and the load terminal 16.

  By utilizing the marginal space in the power load direction, the thermal device 6a is arranged vertically around the electromagnet device 6b, that is, the bimetal 10 is arranged in the vertical direction of the circuit breaker, thereby providing a power supply for the circuit breaker. Without increasing the length in the load direction, the thermal electromagnetic overcurrent tripping device can be configured in the insulating housing 30, and the circuit breaker can be configured in a small size.

  Since the female screw portion 21 a is provided on the shaft of the fixed iron core 21 of the electromagnet device 6 b and the coupling screw 7 is screwed into the female screw portion 21 a to fix the electromagnet device 6 b to the base 1, the electromagnet is tightened by tightening the coupling screw 7. The apparatus 6b can be assembled with almost no inclination with respect to the perpendicular to the bottom surface of the base 1. As a result, the positional relationship between the armature 24 and the trip bar 9a can be made relatively constant, so that the instantaneous trip current, that is, the trip characteristic of the circuit breaker can be stabilized.

  Further, by making the shaft center of the fixed iron core 21 of the electromagnet device 6b and the shaft center of the female screw portion 21a the same, the inclination of the electromagnet device 6b is further reduced as compared with the case where the shaft centers are not the same. Since the positional relationship with the bar 9a can be made more constant, similarly, the tripping characteristics of the circuit breaker can be remarkably stabilized.

  Further, the circuit breaker according to the first embodiment includes an electromagnet device 6b in which the yoke 19 and the electromagnet device main portion 40 are integrated without using a relay member that connects and relays the mover holder 5 and the winding 20b. Can be attached to the base 1, that is, since the relay member whose positioning is unstable at the time of assembly is omitted, the assembly work is facilitated.

  Since the armature 24 is configured to be directly connected to the movable iron core 22 and interlocked with the movement of the movable iron core 22 without adding an intervening member, the number of parts can be reduced as compared with the case where there is an intervening member. Thereby, the assembly man-hour can be reduced. Moreover, since the arrangement space for the interposition member is unnecessary, the overcurrent tripping device 6 can be miniaturized. The armature 24 and the electromagnet device 6b are connected by simply inserting the snap-fit rotary shaft 24b into the shaft hole 19b of the yoke 19 by snap-fit connection, so that the overcurrent tripping device 6 can be easily assembled.

  As described above, according to the circuit breaker of Embodiment 1 of the present invention, when the base mounting portion 21a is provided on the shaft of the fixed iron core 21 and the electromagnet device 6b is installed on the base 1, the electromagnet Since the electric circuit member 19 connected to one end of the winding 20b of the device 6b is interposed and tightened by the tightening body 7 screwed into the base mounting portion 21a, the conventional complete electromagnetic circuit breaker is simply Unlike a circuit breaker with a low rated current product that has been made into a thermodynamic type, a circuit with a thermal electromagnetic overcurrent trip device 6 is also used in a circuit breaker with a low rated current product. The circuit breaker can be made compact.

  In addition, although the base attachment part provided in the fixed iron core 21 of the electromagnet apparatus 6b was demonstrated in the case where the internal thread part 21a and the fastening body are the coupling screws 7, the base attachment part is the external thread part, and the fastening body is a nut. It does not matter. Moreover, the base mounting part and the tightening body may have other shapes that engage with each other.

It is a longitudinal cross-sectional view which shows the circuit breaker in Embodiment 1 of this invention. FIG. 2 is an enlarged view of the overcurrent tripping device shown in FIG. 1. It is an assembly drawing of the electromagnet device main part. It is an assembly drawing of the electromagnet apparatus 6b.

Explanation of symbols

  1 base, 2 lid, 3 fixed contact, 4 movable contact, 5 mover holder, 6 overcurrent trip device, 6a thermal device, 6b electromagnet device, 7 coupling screw, 9 opening / closing mechanism, 19 yoke , 20b Winding, 21 Fixed iron core, 21a Female thread portion, 22 Movable iron core, 24 Armature, 24b Snap-fit rotating shaft, 30 Insulating housing.

Claims (5)

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 the fixed contact An opening / closing mechanism for opening / closing the movable contact; and an overcurrent tripping device connected to the movable contact and operating the opening / closing mechanism in response to an overcurrent, wherein the overcurrent tripping device is fixed A circuit breaker composed of an electromagnet device having an iron core and a thermal device operating by heat due to the overcurrent,
The fixed iron core has a base mounting portion on the shaft of the fixed iron core,
When the electromagnet device is installed on the base, the fixed iron core includes a mover holder that rotatably holds the movable contactor and an electric path member connected to one end of the winding of the electromagnet device. A circuit breaker, wherein the circuit breaker is tightened by a tightening body that engages with the base mounting portion.   2. The circuit breaker according to claim 1, wherein the axis of the base mounting portion is the same as the axis of the fixed iron core.   The circuit breaker according to claim 1, wherein the electric circuit member is a yoke of the electromagnet device.   4. The circuit breaker according to claim 3, wherein the yoke pivotally supports a rotating shaft of an armature that operates the opening / closing mechanism, and the armature is connected to a movable iron core of the electromagnet device. The base mounting portion is a female screw portion, and the fastening body is a joining screw,
5. The circuit breaker according to claim 3 , wherein the yoke and the mover holding body are in direct pressure contact, and the yoke and the mover holding body are fastened by the joining screw. .

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