JPH10172409A - Circuit interrupter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a fused material or the like containing a metal particle or the like hardly adhered to a locking part by forming a locking part of a movable contact at a position distant from an arc generation chamber filled with an arc generated during releasing of the movable contact when the movable contact is in an open-circuit state. SOLUTION: When a short circuit current flows an electric path, an electric magnet 35 of an electromagnetic lead-out part 34 senses an over-current and suctions a plunger 36, and a rod 37 interlocking therewith presses a trigger piece 32b of a latch 32. Engagement of a link engagement groove 32a and the other end of an operation link 31 is disengaged, a movable contact 25a is distant from a fixed contact by biasing force of a main spring 28, and high- speed interruption is performed. Here, when the movable contact 25a is in an open-circuit state, a stopper wall 21a serving to position the movable contact 25a is formed at a position proximal to a shaft 27 as a rotary center point of this movable contact 25a and an arm 26, that is, a position distant from an arc generation chamber 40 filled with ac arc generated during interruption operation, thereby ensuring a given insulation performance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker, and more particularly to an improvement in the insulation performance of a small circuit breaker.

[0002]

2. Description of the Related Art FIG.
2 is a front view showing the inside of a conventional circuit breaker shown in Japanese Patent Publication No. 2 with a cover removed, showing a closed state. FIG. 8 shows FIG.
2 is an enlarged sectional view of a main part showing a circuit breaker of FIG.
In the drawing, 1 is a base, 2 is a fixed contact, 3 is a fixed contact fixed to the fixed contact 2, 4 is an arc runner,
5 is a movable contact, 6 is an arm supporting the movable contact 5, 7 is a shaft attached to the base 1 serving as a pivot point of the arm 6 and the movable contact 5, 8 is an arc extinguishing device,
Reference numeral 9 denotes an arc-extinguishing plate or grid of the arc-extinguishing device 8.
An arc generating chamber 10 including the fixed contact 3 and the movable contact 5 is provided at an entrance of the arc extinguishing device 8. Numeral 11 denotes an electromagnetic trip portion, which includes a yoke 12 and a plunger 1.
3 and the like. Reference numeral 14 denotes an opening / closing mechanism, and 15 denotes an operation handle.

In such a conventional circuit breaker,
The movable contact 5 integral with the arm 6 is opened and closed by the operation handle 15 via the opening and closing mechanism 14 with the shaft 7 as a fulcrum. In the open state shown in FIG. 8, the back surface of the arm 6 collides with the stopper wall 1a provided on the base 1 and stops, and the movable contact 5 is positioned. Further, when a short circuit current flows in the electric circuit in the closed state shown in FIG. 7, an overcurrent is detected by the electromagnetic trip unit 11 and the plunger 13 is attracted, so that the opening and closing mechanism via the arm 6 interlocked therewith. 1
4 operates to move the movable contact 5 away from the fixed contact 3. At this time, the rear surface of the arm 6 collides with the stopper wall 1a and stops, and the movable contact 5 is positioned.

[0004]

In the conventional circuit breaker as described above, the stopper wall 1a for positioning the movable contact 5 at the open position is provided inside the arc generating chamber 10, so that the short-circuit current is reduced. A large amount of a molten material or carbide containing metal particles or the like generated by an arc generated when a large current such as a current is interrupted adheres to the stopper wall 1a and the wall of the base 1 between the movable contact 5 and the fixed contact 2 to provide insulation performance. And there is a problem that it becomes difficult to secure a predetermined insulation performance. Further, there is a problem that even if the stopper wall 1a is moved away from the arc generating chamber 10, the stopper wall 1a cannot be moved upward because the plunger 13 of the electromagnetic trip section 11 is provided.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a metal formed by an arc is formed on a stopper wall on which a movable contact is positioned in an open state and a base wall between the movable contact and the fixed contact. It is an object of the present invention to provide a circuit breaker to which a melt or a carbide containing particles or the like hardly adheres and the insulation performance of the circuit breaker after the breaking operation is small.

[0006]

In a circuit breaker according to the present invention, a movable contact is disposed inside an insulated housing comprising a base and a cover so as to be able to freely contact and separate from a fixed contact. An arm for supporting the movable contact, an opening / closing mechanism for driving the movable contact, an overcurrent release device for operating the opening / closing mechanism in response to an overcurrent to release the movable contact, and opening the movable contact. In a circuit breaker having an arc generation chamber filled with an arc generated at the time of separation and an arc extinguishing device for extinguishing the arc in the arc generation chamber, the locking portion for positioning the open position of the movable contact is arced. It is located away from the generation chamber.

Further, the locking portion is formed so as to protrude from the base near the center point of rotation of the arm. In addition, the locking portion has a first locking surface with which the back surface of the arm contacts at the beginning of the separating operation of the movable contact, and a second locking surface with which the back surface of the arm contacts at the end of the separating operation of the movable contact. A locking surface.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. 1 to 3 show a circuit breaker according to a first embodiment of the present invention. FIG. 1 is a partially cutaway front view showing an open state and FIG. 2 and FIG. FIG. 2 is an enlarged view of a main part showing a mechanical part. FIG. 2 shows a closed state, and FIG. 3 shows an initial state of a breaking operation. In the figure, 21 is a base, 22 is a cover, and both are insulating casings formed of a synthetic resin material. 23 is a fixed contact, 24 is a fixed contact fixed to the fixed contact 23, 25 is a movable contact having a movable contact 25a opposed to and separated from the fixed contact 24, and 26 is a movable contact 25. It is an arm that is integrally supported, and is a long hole 26c in which a U-shaped groove 26a described later, a stopper locking portion 26b, and a shaft 27 described later are engaged.
Are formed. Reference numeral 27 denotes a shaft attached to the base 21 as a pivot point of the arm 26, the movable contact 25, and the movable contact 25a. 28 is the movable contact 2
5a is a main spring for urging the fixed contact 24 away from the fixed contact 24, 29 is a handle, and 30 is this handle 29.
Is an operation link formed by making a round bar material into a U-shape, one end of which is engaged with the handle 29, and the other end is a link engagement groove of a latch 32 described later. 32a. Reference numeral 32 denotes a latch supported by the shaft 27, and a link engagement groove 32a that engages with the other end of the operation link 31;
A trigger piece 32b that receives the pressing force of the rod 37 and a trigger piece 32c that receives a force in the direction of releasing the engagement between the operation link 31 and the link engaging groove 32a by the pressing force due to the bending of the bimetal 33 described later are formed. Have been. The arm 26, the main spring 28, the handle 29, the reset spring 30, the operation link 31, and the latch 32 constitute an opening / closing mechanism.

Reference numeral 33 denotes a bimetal that is heated and curved to the right in accordance with the energizing current. Numeral 34 denotes an electromagnetic trip portion, which is a plunger 3 driven by an electromagnetic force applied to the electromagnet 35
6 and a rod 37 projecting in the direction of the arrow (left direction) by the suction operation of the plunger 36. The bimetal 33 and the electromagnetic trip portion 34 form overcurrent trip means. Reference numeral 38 denotes an arc extinguishing device, and 39 denotes a grid of the arc extinguishing device 38. An arc generating chamber 40 includes the fixed contact 24 and the movable contact 25a, and is filled with an arc generated when the movable contact 25a is opened. 2
Reference numeral 1a denotes a stopper wall which is formed on the base 21 so as to protrude inward and serves to position the open position of the movable contact 25a. It is formed near a shaft 27 which is a dynamic center point.

In the closed state of the circuit breaker thus configured, when a short-circuit current flows in the electric circuit, the electromagnet 35 of the electromagnetic trip section 34 detects an overcurrent and the plunger 36
Is sucked, and the rod 37 interlocked with this is moved in the arrow direction (left direction) as shown in FIG. 3 to press the trigger piece 32b of the latch 32. When the trigger piece 32b is pressed, the latch 32 rotates clockwise about the shaft 27, and the link engagement groove 32a and the other end of the operation link 31 are disengaged. The movable contact 25a rotates clockwise about the shaft 27 via 26, separates from the fixed contact 24, and performs a high-speed breaking operation. The breaking operation will be described in more detail. The arm 26 is moved from the initial state of the breaking operation shown in FIG.
With the force of 8, the position shifts to the open position shown in FIG. A little later, the handle 29 rotates counterclockwise by the force of the reset spring 30, and the operation link 31 interlocked with the handle 29 also attempts to return from the position of FIG. 3 to the position of FIG. The operation link 31 is reliably returned to the state shown in FIG. 1 by the role of the guide of the U-shaped groove 26a, and the latch 32 and the operation link 31 are engaged again. After the breaking operation, the movable contact 25a is connected to the arm 2
6 is positioned in a state where the stopper locking portion 26b is in contact with the stopper wall 21a.

In the arc generating chamber 40, which is a region below the line XX shown in FIG. 1, a large amount of melt or carbide containing metal particles and the like generated by an arc generated when a large current such as a short-circuit current is cut off is severe. In the conventional circuit breaker shown in FIG. 7, the stopper wall 1a for positioning the open position of the movable contact 5 is located very close to this area. In the configuration of the first embodiment according to the present invention, the stopper wall 21a for positioning the open position of the movable contact 25a is located far away from the arc generating chamber 40, and the stopper wall 21a has a molten material containing metal particles and the like. And carbide etc. are difficult to adhere,
A decrease in insulation performance is reduced, and it becomes easy to secure a predetermined insulation performance.

According to the first embodiment, the movable contact 25
When the movable contact 25a is in the open state, the stopper wall 21a for positioning the movable contact 25a is
6 is formed at a position near the shaft 27 serving as a rotation center point, that is, at a position distant from the arc generation chamber 40 where the arc generated at the time of the breaking operation is full, so that the molten material or the carbide adheres to the stopper wall 21a. It becomes difficult to reduce the insulation performance, and it becomes easy to secure a predetermined insulation performance.

Embodiment 2 FIG. 4 to 6 are enlarged views of a main part showing a switching mechanism of a circuit breaker according to Embodiment 2 of the present invention. FIG. 4 is a closed state of the circuit breaker, and FIG. FIG. 6 shows an initial state of the operation, and FIG. 6 shows an end state of the breaking operation of the circuit breaker. In the drawings, the same reference numerals as those in FIGS. 1 to 3 denote the same parts, and a description thereof will be omitted. 1
Reference numeral 21 denotes a stopper wall formed so as to protrude in the inner direction of the base 21, and has a first stopper surface 121a and a second stopper surface 121b.

When a short-circuit current flows in the electric circuit in the closed state shown in FIG. 4, the electromagnet 35 of the electromagnetic trip section 34 (shown in FIG. 1) senses the overcurrent, the plunger 36 is attracted, and the rod 37 interlocked therewith. Moves in the arrow direction (left direction) shown in FIG. 5 and presses the trigger piece 32 b of the latch 32. When the trigger piece 32b is pressed, the latch 32
7, the link engagement groove 32a and the other end of the operation link 31 are disengaged from each other, and the movable contact 25 is moved through the arm 26 by the urging force of the main spring 28.
a rotates clockwise about the shaft 27 and separates from the fixed contact 24 to perform a known breaking operation. In the initial state of the breaking operation shown in FIG. 5, the movable contact 25a is pushed through the latch 32 by the rod 37 in order to quickly separate the movable contact 25a, and the arm 26 is connected to the shaft 27 and the long hole 2
6c, the stopper 26b of the arm 26 moves to the first stopper surface 121.
a. Next, in the final state of the shutoff operation shown in FIG. 6, the stopper locking portion 26b is in the second stopper surface 121b.
And the movable contact 25a is completely separated.

According to the second embodiment, the stopper wall 1
21, a first stopper surface 121a with which the stopper locking portion 26b of the arm 26 comes into surface contact in the early stage of the breaking operation.
And the second stopper surface 121b with which the stopper locking portion 26b of the arm 26 comes into surface contact at the end of the breaking operation, so that the stopper locking portion 26b of the arm 26 and the second As a result, the stopper wall 121 or the arm 26 is unlikely to be damaged even if the blocking operation is repeatedly performed.

[0016]

Since the present invention is configured as described above, it has the following effects.

When the movable contact is in the open state, the locking portion protruding inward from the base for positioning the open position of the movable contact is filled with an arc generated when the movable contact is opened. Since it is formed at a position away from the chamber, it is difficult for molten matter or carbide containing metal particles or the like to adhere to the locking portion, so that a decrease in insulation performance is reduced,
It is easy to secure a predetermined insulation performance.

The locking portion has a first locking surface against which the back surface of the arm comes into contact at the beginning of the separating operation of the movable contact, and a back surface of the arm at the end of the separating operation of the movable contact. Since the second contact surface is in contact with the first engaging surface of the stopper wall, the back surface of the arm supporting the movable contact comes into surface contact with the first engaging surface of the stopper wall at the beginning of the interruption operation. Also, the arm or the locking portion is less likely to be damaged.

[Brief description of the drawings]

FIG. 1 is a front view showing the inside of a circuit breaker according to a first embodiment of the present invention with a part cut away, showing an open circuit state.

FIG. 2 is an enlarged view of a main part showing a switching mechanism of the circuit breaker according to the first embodiment of the present invention, showing a closed state;

FIG. 3 is an enlarged view of a main part showing a switching mechanism of the circuit breaker according to the first embodiment of the present invention, showing an initial state of a breaking operation.

FIG. 4 is an enlarged view of a main part showing a switching mechanism of a circuit breaker according to Embodiment 2 of the present invention, showing a closed state.

FIG. 5 is an enlarged view of a main part showing a switching mechanism of a circuit breaker according to a second embodiment of the present invention, showing an initial state of a breaking operation.

FIG. 6 is an enlarged view of a main part showing an opening / closing mechanism of a circuit breaker according to Embodiment 2 of the present invention, showing an end state of a breaking operation.

FIG. 7 is a front view showing the inside of a conventional circuit breaker with a cover removed.

8 is an enlarged sectional view of a main part showing an open state of the circuit breaker of FIG. 7;

[Explanation of symbols]

Reference Signs List 21 base, 21a stopper wall, 22 cover, 23 fixed contact, 24 fixed contact, 25 movable contact, 25a movable contact, 26 arm, 2
6b stopper locking part, 27 axes, 32 latches,
33 bimetal, 34 electromagnetic trip unit, 38 arc extinguishing device, 40 arc generating chamber, 121 stopper wall,
121a first stopper surface, 121b second stopper surface,

Claims (3)

[Claims] 1. A movable contact, which is disposed inside an insulated housing composed of a base and a cover so as to be able to freely contact and separate from a fixed contact, an arm supporting the movable contact, and the movable contact. An opening / closing mechanism to be driven; an overcurrent trip device for operating the opening / closing mechanism in response to an overcurrent to open the movable contact; and an arc generating chamber filled with an arc generated when the movable contact is opened. And an arc extinguishing device for extinguishing the arc in the arc generating chamber, wherein a locking portion for positioning the open position of the movable contact is arranged at a position distant from the arc generating chamber. A circuit breaker, characterized in that: 2. The circuit breaker according to claim 1, wherein the locking portion projects from the base near the rotation center point of the arm. 3. The locking portion contacts the first locking surface with which the back surface of the arm contacts at the beginning of the separating operation of the movable contact, and the back surface of the arm at the end of the separating operation of the movable contact. 3. The circuit breaker according to claim 1, further comprising a second locking surface.