JPWO2015004697A1 - Circuit breaker - Google Patents

Abstract

The circuit breaker is miniaturized by downsizing the electromagnetic trip device that affects the inverse time characteristics. In a circuit breaker including an opening / closing mechanism 30 that opens and closes a contact portion and an electromagnetic trip device 40 that trips the opening / closing mechanism 30, when the movable iron piece 49 is not attracted to the oil dash pot 43, the movable iron piece The free end 50b of the spring 50 is at a first position on the yoke 42 side with respect to the line A connecting the rotational axis of the movable iron piece 49 and the fixed end 50a of the movable piece spring 50, and the movable iron piece 49 is oil dash. The electromagnetic trip device 40 is configured so that the free end 50b comes to the second position on the side opposite to the yoke 42 beyond the line A from the yoke 42 side when attracted to the pot 43.

Description

  The present invention relates to a circuit breaker provided with an electromagnetic trip device using an oil dashpot, and more particularly to an improvement in driving force for the electromagnetic trip device to trip an opening / closing mechanism.

  An electromagnetic device constituting an electromagnetic trip device of a conventional circuit breaker has an oil dashpot type fixed iron core fixed to one leg portion of an L-shaped yoke made of a magnetic plate and the other leg portion. The movable iron piece is rotatably supported so as to face the contact surface of the fixed iron core, and the movable iron piece is held by inserting a column on the yoke side into a window hole or a notch groove of the movable iron piece. In addition, a spring for biasing the movable iron piece is provided so as to enlarge the gap between the movable iron piece and the contact surface of the fixed iron core. Furthermore, one end of the iron core provided in the oil dash pot of the fixed iron core is coupled to one leg portion of the L-shaped yoke to form a magnetic circuit, and the attraction force that makes this magnetic circuit a closed circuit is utilized. The movable iron piece is rotated to open the opening / closing mechanism.

  In this specification, if an attempt is made to reduce the size of the electromagnetic tripping device while maintaining the tripping load of the tripping mechanism unit, there may be a case where sufficient suction force for tripping the tripping mechanism unit cannot be obtained. Therefore, for the purpose of increasing the attractive force without changing the number of turns of the coil that constitutes the electromagnetic device that affects the inverse time characteristics of the circuit breaker, the tip of the other leg of the yoke should be perpendicular to the fixed core side. There has been known an electromagnetic tripping device in which a bent portion is provided and an attractive area is increased by the bent portion to improve the attractive force (see, for example, Patent Document 1).

JP 2001-307614 A FIG.

  In the electromagnetic tripping device in the conventional circuit breaker as described above, if the electromagnetic tripping device is downsized and configured while maintaining the tripping load of the switching mechanism portion, Sufficient driving force may not be obtained.

  The present invention has been made to solve the above-described problems, and improves the driving force in an electromagnetic trip device for tripping an opening / closing mechanism without increasing the size of the electromagnetic trip device. The circuit breaker which can do is obtained.

  A circuit breaker according to the present invention includes a movable contact, a fixed contact that contacts and separates from the movable contact, an opening / closing mechanism that opens and closes the movable contact, and an opening / closing mechanism that is connected to the movable contact. An electromagnetic tripping device, and the electromagnetic tripping device includes a yoke made of a magnetic plate, a fixed iron core fixed to one leg of the yoke, and wound around the fixed iron core. A coil connected in series with the contact, a movable iron piece having a suction surface opposed to the armature surface of the fixed iron core, which is rotatably held by the holding portion of the other leg portion of the yoke, and a fixed end is the holding portion In a circuit breaker comprising a movable piece spring held by the fixed end holding portion of the yoke located away from the free end and held by the movable iron piece, when the movable iron piece is not attracted to the fixed iron core, The free end of the movable iron spring is the pivot of the movable iron When the movable iron piece is attracted to the fixed iron core, the free end of the movable iron piece spring moves from the first position to the movable iron piece. And the second position beyond the line connecting the rotating shaft center and the fixed end of the movable piece spring.

  According to the present invention, when the fixed iron core attracts the movable piece, the urging force of the movable piece spring is added to the attractive force by the magnetic force, so that it is possible to secure a driving force for detaching the opening / closing mechanism, and to It is possible to reduce the size of the circuit breaker by reducing the size of the removing device.

It is a longitudinal cross-sectional view which shows the whole structure of the circuit breaker in Embodiment 1 of this invention. It is an enlarged side view which shows the electromagnetic tripping apparatus in Embodiment 1 of this invention. It is an enlarged view which shows the yoke of the electromagnetic tripping device shown in FIG. 2, (a) is a side enlarged view, (b) is a front enlarged view. It is an enlarged view which shows the movable piece of the electromagnetic tripping device shown in FIG. 2, (a) is a plane enlarged view, (b) is a side enlarged view. It is explanatory drawing for demonstrating the effect | action of the movable piece spring in the state in which the movable piece is not attracted | sucked in the electromagnetic tripping apparatus shown in FIG. It is explanatory drawing for demonstrating the magnetic flux in the state in which the movable piece is not attracted | sucked in the electromagnetic type tripping apparatus shown in FIG. It is explanatory drawing for demonstrating the magnetic flux in the state by which the movable piece was attracted | sucked in the electromagnetic type tripping apparatus shown in FIG. It is explanatory drawing for demonstrating an effect | action of the movable piece spring in the state in which the movable piece was attracted | sucked in the electromagnetic tripping apparatus shown in FIG. It is explanatory drawing for demonstrating the effect | action of the movable piece spring in the state in which the movable piece is not attracted | sucked in the electromagnetic tripping apparatus in Embodiment 2 of this invention. It is explanatory drawing for demonstrating the effect | action of a movable piece spring in the state in which the movable piece was attracted | sucked in the electromagnetic tripping apparatus shown in FIG.

Embodiment 1 FIG.
1 is a longitudinal sectional view showing the overall configuration of a circuit breaker according to Embodiment 1 of the present invention, FIG. 2 is an enlarged side view showing an electromagnetic trip device, and FIG. 3 is an illustration of the electromagnetic trip device shown in FIG. FIG. 4 is an enlarged view showing a yoke, (a) is an enlarged side view, (b) is an enlarged front view, FIG. 4 is an enlarged view showing a movable piece of the electromagnetic tripping device shown in FIG. 2, and (a) is an enlarged plan view. FIG. 5B is an enlarged side view, FIG. 5 is an explanatory view for explaining the action of the movable piece spring in the state where the movable piece is not attracted in the electromagnetic tripping device shown in FIG. 2, and FIG. FIG. 7 is an explanatory diagram for explaining the magnetic flux in a state where the movable piece is not attracted in the electromagnetic trip device shown in FIG. 7, and FIG. 7 is a diagram for explaining the magnetic flux in the state where the movable piece is attracted in the electromagnetic trip device shown in FIG. FIG. 8 is an explanatory diagram for the purpose of carrying out the operation, and FIG. 8 shows the electromagnetic tripping device shown in FIG. It is an explanatory view for explaining the operation of the movable piece spring state.

  In FIG. 1, a circuit breaker 101 is configured using a housing 10 that includes a base 11 and a cover 12 made of an insulating material. On the base 11, circuit breaker units (for example, three in the case of three phases) connected to the electric circuit are arranged in parallel for each pole, and a well-known delay entry mechanism is disposed above the central circuit breaker unit. An opening / closing mechanism 30 having the above is disposed.

The cover 12 covers the circuit breaker unit of each phase on the base 11 and the opening / closing mechanism 30, and the operation handle 31 of the opening / closing mechanism 30 protrudes from the window hole 12 a of the cover 12.
The circuit breaker units for each phase are configured in the same manner, and the crossbar 13 is arranged on the base 11 so as to be orthogonal to the circuit breaker units for each phase in common with the circuit breaker units for each phase. The

  Each circuit breaker unit for each phase includes a power supply side terminal 20 that is a first external terminal provided on the base 11, a fixed contact 21 that extends from the power supply side terminal 20 and has a fixed contact 22, and a fixed contact. A movable contact 23 that contacts and separates from the contact 22, a movable contact 24 that has the movable contact 23 at one end, and is held freely movable up and down by the crossbar 13. 25, an electromagnetic trip device 40 that trips the opening / closing mechanism 30, and a load-side terminal 26 that is connected to the electromagnetic trip device 40 and is a second external terminal provided on the base 11. And have. The fixed contact 22 and the movable contact 23 constitute an open / close contact that opens and closes the electric circuit. An arc extinguishing device 27 having an arc extinguishing plate 27 a is provided in the vicinity of the fixed contact 22 and the movable contact 23. If the movable contact 23 comes into contact with the fixed contact 22, the electrical circuit between the terminals 20 and 26 is turned on. If the movable contact 23 is separated from the fixed contact 22, the electrical circuit between the terminals 20 and 26. Is turned off.

  The cross bar 13 is moved up and down by the opening / closing mechanism 30. When the cross bar 13 moves up and down, the movable contacts 24 of the circuit breaker units of the poles move up and down simultaneously. As the movable contactor 24 moves up and down, the movable contact 23 contacts and separates from the fixed contact 22. In addition, the opening / closing mechanism 30 includes a known trip bar 33 that is driven by an electromagnetic tripping device 40 for each pole.

  As shown in FIG. 2, the electromagnetic trip device 40 includes a coil 41 connected to the movable contact 24 and the load-side terminal 26 and wound to convert an energization current into a magnetic flux, and an electromagnetic plate 41. The L-shaped yoke 42 through which the magnetic flux passes through and the time at which the iron core is adsorbed to the pipe lid by the viscosity of the oil are controlled by using the magnetic flux of the coil 41 fixed to one leg portion of the yoke 42, and the time limit is reached. And an oil dash pot 43 for determining the characteristics. The oil dash pot 43 includes a pipe 44 around which the coil 41 is wound, a pipe lid 45 serving as a lid for the pipe 44, an iron core 47 provided with oil 46 in the pipe 44, and the iron core 47 An iron core spring 48 is provided between the pipe lids 45 and biases the iron core 47 in a direction away from the pipe lid 45. The “fixed iron core” described in the claims is the oil dash pot 43 described above.

In addition, the electromagnetic tripping device 40 opposes the pipe lid 45 and is movable freely held by a holding portion 42a provided on the other leg portion of the yoke 42, and a bent portion 42b of the yoke 42. And a movable piece spring 50 which is provided between the end portions 49e of the movable piece 49 and biases the movable piece 49.
As shown in FIG. 3, the bent portion 42b of the yoke 42 is provided by bending a part of the yoke from the vicinity of the holding portion 42a.

  As shown in FIG. 4, the movable piece 49 has a suction surface 49 a that is attracted to the pipe lid 45, a fulcrum 49 b that is the rotational axis of the movable piece 49, and a penetration for passing the extension 42 c of the yoke 42. A hole 49c, a bent portion 49d for forming a magnetic circuit to the desired yoke 42 in the through hole 49c, and a free end holding portion for holding the movable piece spring 50 provided at the end portion 49e of the movable piece 49 49e1. The movable piece spring 50, which is a compression spring, is provided between the fixed end holding portion 42b1 and the free end holding portion 49e1 provided at the tip of the bent portion 42b of the yoke 42. Here, the fixed end holding portion 42b1 side is the fixed end 50a of the movable piece spring 50, and the free end holding portion 49e1 side is the free end 50b of the movable piece spring 50.

  In the conventional electromagnetic tripping device, it is difficult to sufficiently increase the attractive force of the movable piece in order to maintain the inverse time characteristic of the circuit breaker. Therefore, in the case of exclusive use for alternating current, the opening / closing mechanism is removed using the inertial force of the movable piece caused by the vibration of the movable piece at a commercial frequency. On the other hand, when a circuit breaker equipped with this electromagnetic trip device is applied to a DC circuit, the movable piece does not vibrate, so that the inertial force of the movable piece cannot be used as in the AC circuit. Therefore, for DC, it was necessary to change the number of turns of the coil, the viscosity of the oil, and the iron core spring.

In order to solve this, in the present embodiment, the movable piece spring 50 is a compression spring, and the distance between the fixed end holding portion 42b1 and the free end holding portion 49e1 is shorter than the distance between the free end holding portion 49e1 and the fulcrum 49b. In other words, in other words, the fixed end holding portion 42b1 is provided closer to the free end 50b than the fulcrum 49b.
In a state where a current equal to or lower than the rated current flows through the electric circuit, as shown in FIG. 5, a fixed end holding portion that holds a fulcrum 49 b that is the rotation center of the movable piece 49 and a fixed end 50 a of the movable piece spring 50. A free end holding portion 49e1 that holds the free end 50b of the movable piece spring 50 is located on the yoke 42 side (on the right side in FIG. 5) from the line A connecting with 42c.

  From this state, when the free end holding portion 49e1 and the free end 50b rotate in the direction of the line A, the distance from the fulcrum 49b to the free end holding portion 49e1 does not change, so the length L1 of the movable piece spring 50 is free. The closer the end 50b is to the line A, the shorter the end 50b, and the movable piece spring 50 is further compressed. Therefore, the urging force F1 acts on the free end 50b in the direction in which the length L1 of the movable piece spring 50, which is a compression spring, becomes longer. That is, a counterclockwise force moment M1 is generated around the fulcrum 49b. Due to the moment M1 of the force, the attracting surface 49a of the movable piece 49 is urged away from the pipe cover 45, which is a contact surface, and rotates until the end portion 49e contacts the yoke 42. The “first position” described in the claims is a position where the free end 50 b of the movable piece spring 50 is closer to the yoke 42 than the line A.

Next, the breaking operation of the circuit breaker 101 will be described.
When a current flows in the electric circuit, an exciting current flows in the coil 41, and the magnetic flux generated by this exciting current is, as shown in FIG. 6, the first magnetic gap G1 between the yoke 42 → the iron core 47 → the iron core 47 and the pipe lid 45. → Pipe lid 45 → Second magnetic gap G2 between the movable piece 49 and the pipe lid 45 → movable piece 49 → passes through a magnetic circuit consisting of the yoke 42. At this time, if an overcurrent of a predetermined value or more flows in the electric circuit, the magnetic flux generated by this overcurrent generates an attractive force that attracts the iron core 47 toward the pipe lid 45, and this attractive force is applied to the iron core spring 48. It will exceed the power. Then, as shown in FIG. 7, the iron core 47 is attracted to the pipe lid 45 side by a viscous resistance of the oil 46, and the first magnetic gap G1 is changed from the normal L2 shown in FIG. It decreases to L3 shown. Since the iron core 47 is attracted to the pipe lid 45 and the first magnetic gap G1 decreases, the magnetic flux B of the second magnetic gap G2 between the movable piece 49 and the pipe lid 45 gradually increases.

  When the increased suction force exceeds the load on which the movable piece 49 is urged by the movable piece spring 50, the movable piece 49 starts to rotate clockwise around the fulcrum 49b. When the free end 50b of the movable piece spring 50 comes on a line A connecting the fulcrum 49b that is the rotation center of the movable piece 49 and the fixed end holding portion 42c that holds the fixed end 50a of the movable piece spring 50. The movable piece spring 50 is in the most compressed state. From this state, when the movable piece 49 further rotates in the clockwise direction and comes to the side opposite to the yoke 42 (on the left side in FIG. 8) with respect to the line A beyond the line A, as shown in FIG. Since the distance to the free end holding portion 49e1 does not change, the movable piece spring 50 is released from the most compressed state and starts to expand, and the length L1 of the movable piece spring 50 is increased at the free end 50b. The urging force F2 in the direction works.

  In other words, the urging force F2 generates a clockwise moment M2 around the fulcrum 49b, and the movable piece 49 further rotates clockwise by this force moment M2, and the end 49e trips. By pushing the bar 33, the cross bar 13 of the opening / closing mechanism 30 is driven, and the movable contact 24 is separated from the fixed contact 21. The movable contact 23 is separated from the fixed contact 22 by the movement of the movable contact 24. When the movable contact 23 is released, the arc generated by the flowing current is extinguished by the arc extinguishing device 27 and the interruption is completed.

At this time, the end portion 49e of the movable piece 49 contacts the trip bar 33 after the free end 50b rotates from the first position to the second position beyond the line A. That is, the tripping of the opening / closing mechanism 30 by the electromagnetic tripping device 40 is performed after the free end 50b exceeds the line A. As a result, the moment M2 of the force acting on the movable piece 49 is added to the attraction force by the magnetic flux B, so that a driving force sufficiently exceeding the tripping load of the opening / closing mechanism 30 is exhibited.
Since the on / off operation is the same as that of a known circuit breaker, a description thereof will be omitted.
The “second position” described in the claims means the side opposite to the yoke 42 in which the free end 50b of the movable piece spring 50 has moved beyond the line A from the first position, that is, with respect to the line A. It is a position opposite to the first position.

  According to the present embodiment, the movable piece spring 50 is a compression spring, the fixed end holding portion 42b1 is provided near the free end 50b from the fulcrum 49b, and the movable iron piece 49 is adsorbed to the old dash pot 43. The free end 50b of the movable piece spring 50 is on the side of the yoke 42 with respect to the line A, and the free end 50b exceeds the line A from the side of the yoke 42 when the movable iron piece 49 is attracted to the ordash pot 43. Since the oil dash pot 43 attracts the movable piece 49 because it is on the side opposite to the yoke 42, the urging force of the movable piece spring 50 is added to the attractive force by the magnetic force, and the driving force that the movable piece 49 pushes the trip bar 33 increases. Therefore, the number of turns of the coil 41 can be reduced and the electromagnetic trip device 40 can be downsized, and the circuit breaker can be downsized.

  Further, when the oil dash pot 43 attracts the movable piece 49, the biasing force of the movable piece spring 50 is added to the attracting force by the magnetic force, so that the AC and DC electromagnetic trip devices 40 are shared. It is also possible.

  In this embodiment, the fixed contact 22 is provided with the fixed contact 22 and the movable contact 24 is provided with the movable contact 23. However, the fixed contact 22 and the movable contact 23 are not provided, and the fixed contact 22 is provided. 21 and the movable contact 24 may directly contact and separate.

Embodiment 2. FIG.
FIG. 9 is an explanatory view for explaining the action of the movable piece spring in a state where the movable piece is not attracted in the electromagnetic trip device according to the second embodiment of the present invention, and FIG. 10 is an electromagnetic trip shown in FIG. It is explanatory drawing for demonstrating an effect | action of the movable piece spring in the state by which the movable piece was attracted | sucked in the apparatus. In the first embodiment, the movable piece spring 50 of the electromagnetic trip device 40 is configured by a compression spring, but in the electromagnetic trip device 60 of the present embodiment, the movable piece spring 51 is configured by a tension spring. Is.

  In FIG. 9, an electromagnetic trip device 60 is connected to the movable contact 24 and the load-side terminal 26, and is wound with a coil 61 wound to convert an energized current into a magnetic flux, and an electromagnetic plate. L-shaped yoke 62 to be passed through, and the time limit characteristic is determined by controlling the time that the iron core is adsorbed to the pipe lid by the viscosity of oil using the magnetic flux of the coil 61 fixed to one leg of the yoke 62 And an oil dash pot 63. The oil dash pot 63 includes a pipe 64 around which the coil 61 is wound, a pipe lid 65 that serves as a lid for the pipe 64, an iron core 67 provided with the oil 66 in the pipe 64, and the iron core 67. An iron core spring 68 is provided between the pipe lids 65 and biases the iron core 67 away from the pipe lid 65.

  The electromagnetic trip device 60 is provided on the yoke 62 and a movable piece 69 that faces the pipe lid 65 and is held freely by a holding portion 62 a provided on the other leg portion of the yoke 62. A movable piece spring 51 that is stretched between the fixed end holding portion 62 b and the end portion 69 e of the movable piece 69 and biases the movable piece 69 is provided.

  Furthermore, the yoke 62 is provided with a holding portion 62 a that holds the movable piece 69 and a fixed end holding portion 62 b that is provided above the holding portion 62 a and holds the fixed end of the movable piece spring 51. In addition, the movable piece 69 is provided at an adsorption surface 69 a that is attracted to the pipe lid 65, a fulcrum 69 b that is the rotation center of the movable piece 69, and an end portion 69 e of the movable piece 69, and holds the movable piece spring 51. A free end holding portion 69e1.

The movable piece spring 51, which is a tension spring, is stretched between the fixed end holding portion 62b and the free end holding portion 69e1 of the yoke 62, and the fixed end holding portion 62b side is the fixed end 51a of the movable piece spring 51. The portion 69e1 side is the free end 51b of the movable piece spring 51. The distance between the fixed end holding portion 62b and the free end holding portion 69e1 is configured to be longer than the distance between the free end holding portion 69e1 and the fulcrum 69b.
Since other configurations are the same as those in the first embodiment, description thereof is omitted.

Next, the operation will be described.
With the configuration as described above, in a state where a current equal to or lower than the rated current flows, the fulcrum 69b that is the rotation center of the movable piece 69 and the fixed end 51a of the movable piece spring 51 are held as shown in FIG. The free end 51b of the movable piece spring 51 and the free end holding portion 69e1 holding the free end 51b are on the yoke 62 side (right side on the paper surface of FIG. 9) from the line C connecting the fixed end holding portion 62b. .

  When the free end holding portion 69e1 and the free end 51b are rotated toward the line C from this state, the distance from the fulcrum 69b to the free end holding portion 69e1 does not change, so the length of the movable piece spring 51 is the free end. The closer 51b is to the line C, the longer it becomes, and the movable piece spring 51 is further extended. Therefore, the urging force F3 acts on the free end 51b in a direction in which the length of the movable piece spring 51, which is a tension spring, becomes shorter.

  Therefore, the urging force F3 of the movable piece spring 51 generates a moment M3 of a counterclockwise force around the fulcrum 69b. By this moment M3 of the force, the attracting surface 69a of the movable piece 69 is urged away from the pipe lid 65, which is the contact surface, that is, in the direction of arrow D, and rotated until the end 69e contacts the yoke 62. To do. The “first position” described in the claims is a position where the free end 51 b of the movable piece spring 51 is closer to the yoke 62 than the line C.

Next, the blocking operation will be described.
As in the first embodiment, when a current flows in the electric circuit, an exciting current flows in the coil 61, and the magnetic flux generated by this exciting current is a first magnetic gap between the yoke 62 → the iron core 67 → the iron core 67 and the pipe lid 65. G3 → pipe lid 65 → second magnetic gap G4 between movable piece 69 and pipe lid 65 → movable piece 69 → passes a magnetic circuit consisting of yoke 62. At this time, if an overcurrent of a predetermined value or more flows in the electric circuit, the magnetic flux generated by this overcurrent generates an attractive force that attracts the iron core 67 to the pipe lid 65, and this attractive force generates the urging force of the iron core spring 68. It will exceed.

  Then, as shown in FIG. 10, the iron core 67 is attracted toward the pipe lid 65 after a predetermined time due to the viscous resistance of the oil 66, and the first magnetic gap G3 is changed from the normal L4 shown in FIG. It decreases to L5 shown in FIG. Since the iron core 67 is attracted to the pipe lid 65 and the first magnetic gap G3 is reduced, the magnetic flux B of the second magnetic gap G4 between the movable piece 69 and the pipe lid 65 gradually increases.

When the increased suction force exceeds the load that urges the movable piece 69 by the movable piece spring 51, the movable piece 69 starts to rotate clockwise around the fulcrum 69b. When the free end 51b of the movable piece spring 51 comes on a line C connecting the fulcrum 69b that is the rotation center of the movable piece 69 and the fixed end holding portion 62b, the movable piece spring 51 is in the most extended state. Become. From this state, when the movable piece 69 further rotates clockwise and exceeds the line C and comes to the side opposite to the yoke 62 with respect to the line C (on the left side in FIG. 10), as shown in FIG. Since the distance from the free end holding portion 69e1 does not change, the movable piece spring 51 is released from the most extended state and starts to be compressed, and the length of the movable piece spring 51 is shortened at the free end 51b. The urging force F4 in the direction works.
The “second position” described in the claims means the side opposite to the yoke 62 where the free end 51b of the movable piece spring 51 has moved beyond the line C from the first position, that is, the line C. It is a position opposite to the first position.

  Then, the urging force F4 of the movable piece spring 51 generates a moment M4 of the clockwise force around the fulcrum 69b. Due to the moment M4 of the force, the suction surface 69a of the movable piece 69 is urged in the direction approaching the pipe lid 65 that is the contact surface, that is, in the direction of arrow E, and rotates clockwise. By this rotation, the end 69e pushes the trip bar 33, and the cross bar 13 of the opening / closing mechanism 30 is driven to separate the movable contact 24 from the fixed contact 21. The movable contact 23 is separated from the fixed contact 22 by the movement of the movable contact 24. When the movable contact 23 is released, the arc generated by the flowing current is extinguished by the arc extinguishing device 27 and the interruption is completed.

At this time, the end 69e of the movable piece 69 contacts the trip bar 33 after the free end 51b rotates from the first position to the second position beyond the line C. That is, the tripping of the opening / closing mechanism 30 by the electromagnetic tripping device 60 is performed after the free end 51b exceeds the line C.
As a result, the moment M4 of the force acting on the movable piece 69 is added to the attraction force by the magnetic flux, thereby exhibiting a driving force sufficiently exceeding the tripping load of the opening / closing mechanism 30.

    According to the present embodiment, the movable piece spring 51 is a tension spring, the fulcrum 69b is provided closer to the free end 51b than the fixed end holding portion 62b, and the movable iron piece 69 is attracted to the old dash pot 63. When it is not, the free end 51b of the movable piece spring 51 is on the yoke 62 side with respect to the line C, and when the movable iron piece 69 is attracted to the ordash pot 63, the free end 51b exceeds the line C from the yoke 62 side. Therefore, when the oil dash pot 63 attracts the movable piece 69, the urging force of the movable piece spring 51 is added to the attractive force by the magnetic force, and the driving force that the movable piece 69 pushes the trip bar 33 is generated. Therefore, the number of turns of the coil 61 can be reduced and the electromagnetic tripping device 60 can be downsized, and the circuit breaker can be downsized.

  Further, when the oil dash pot 63 attracts the movable piece 69, the biasing force of the movable piece spring 51 is added to the attracting force by the magnetic force, so that the AC and DC electromagnetic trip devices 60 can be shared. Is also possible.

10 housing, 11 base, 12 cover,
20 power supply side terminal, 21 fixed contact, 22 fixed contact, 23 movable contact,
24 movable contacts, 26 load side terminals, 30 opening / closing mechanism,
40 electromagnetic trip device, 41 coil,
42 yoke, 42b bent part, 42b1 fixed end holding part,
43 Oil Dash Pot,
49 movable piece, 49e end, 49e1 free end holding part,
50 movable single spring, 50a fixed end, 50b free end,
101 Circuit breaker.

Claims (4)

A movable contact; a stationary contact that contacts and separates from the movable contact; an opening / closing mechanism that opens and closes the movable contact; and an electromagnetic pull that is connected to the movable contact and trips the opening / closing mechanism. A removal device,
The electromagnetic trip device includes a yoke made of a magnetic plate, a fixed iron core fixed to one leg of the yoke, a coil wound around the fixed iron core and connected in series with the two contacts. The movable iron piece having a suction surface opposed to the armature surface of the fixed iron core, the movable iron piece being rotatably held by the holding portion of the other leg portion of the yoke, and the fixed end being away from the holding portion. In a circuit breaker comprising: a movable piece spring held by a fixed end holding portion of a yoke, and a free end held by a free end holding portion provided in the movable iron piece,
When the movable iron piece is not attracted to the fixed iron core, the free end is at a first position on the yoke side with respect to a line connecting the rotation axis of the movable iron piece and the fixed end, The circuit breaker according to claim 1, wherein when the movable iron piece is adsorbed to the fixed iron core, the free end is in a second position beyond the line from the first position. 2. The movable piece spring is a compression spring, and a distance between the fixed end holding portion and the free end holding portion is shorter than a distance between the free end holding portion and the rotation axis. Circuit breaker described in. 2. The movable piece spring is a tension spring, and a distance between the fixed end holding part and the free end holding part is longer than a distance between the free end holding part and the rotation axis. Circuit breaker described in. 4. The circuit according to claim 1, wherein the tripping of the opening / closing mechanism by the electromagnetic tripping device is performed after the free end exceeds the line. 5. Circuit breaker.

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