JP2953114B2 - Circuit breaker voltage trip device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker, such as a circuit breaker for wiring, which operates an electromagnet according to an external command and acts on a trip crossbar for locking a tripping mechanism. The present invention relates to a tripping voltage trip device.

[0002]

2. Description of the Related Art FIG. 4 is a longitudinal sectional view showing a closed state of a circuit breaker (wiring breaker) provided with the above-mentioned conventional voltage trip device. In the figure, a current flows from a fixed contact 1 integrated with a power supply terminal to a load contact 5 through a movable contact 2, a lead wire 3, and a heater conductor 4a of an overcurrent trip device 4.
The movable contact 2 is pressed by the fixed contact 1 under the action of an opening / closing spring 9 via a toggle link 8 connecting a holder 6 holding the movable contact 2 and a latch 7 of an opening / closing mechanism.
The latch 7 receiving the reaction force from the toggle link 8 is a support shaft 1
Although a counterclockwise torque in the figure is received around 0, the locking end 7a is locked by the latch receiver 11 and is held in the reset state in the figure.

The latch receiver 11 receives a torque around the support shaft 12 in the clockwise direction in the figure by the force from the latch 7, and the contact end 11 a of the latch receiver 11 is attached to a claw 14 fixed to the trip cross bar 13. It abuts and is locked in the illustrated state. At this time, the force acting on the pawl 14 from the latch receiver 11 is set so as to pass through the center of the support shaft 15 of the trip crossbar 13, and the trip crossbar 13 receives the torque shown in FIG. I have. The trip crossbar 13 is integrally provided with a trip arm 16 that receives an operating force from the overcurrent trip device 4 and an operating piece 18 that receives an operating force from the voltage trip device 17 that is the subject of the present invention. I have.

When an overcurrent flows through such a circuit breaker, the overcurrent tripping device 4 operates to push the trip arm 16 to the left in the drawing by the bimetal 4b or the armature 4c, thereby causing the trip crossbar 13 to rotate counterclockwise. Rotate in the direction. As a result, the latch receiver 11 is disengaged from the claw 14 and pivots clockwise to release the latch 7. As a result, the latch 7 rotates counterclockwise, and in the process, the action of the opening / closing spring 9 is reversed, and the toggle link 8 collapses,
The movable contact 2 is quickly pulled up in the clockwise direction to interrupt the current.

The overcurrent trip unit 4 detects the overcurrent and trips the circuit breaker as described above. The voltage trip unit 17 trips the circuit breaker in response to a command from a distance. The movable contact 2 is separated by rotating the trip cross bar 13 in the same manner via the operation piece 18. Voltage trip device 1
Reference numeral 7 is attached to the main body case of the circuit breaker so as to be located on the side of the opening / closing mechanism. This will be described below with reference to FIGS. Here, FIG. 5 is a plan view of the voltage trip device 17, FIG. 6 is a side view thereof, FIG. 7 is an enlarged view of a main part of FIG. 6 showing a state at the start of the trip operation, and FIG. It is a principal part enlarged view which shows the state in the middle.

First, in FIGS. 5 and 6, reference numeral 19 denotes a base made of a molded resin, reference numeral 20 denotes a yoke held by press-fitting therein, and a cylindrical fixed magnet 21 inside the yoke 20, which faces the same. Movable magnet 22,
And an electromagnetic coil 23 surrounding them. A two-armed trip lever 24 is rotatably supported by a support shaft 25 on the yoke 20 in front of the movable magnet 22.
And the other arm 24b is connected to the trip crossbar 13
Over the operating piece 18 and mesh with it. The trip lever 24 is urged in a counterclockwise direction in FIG. 6 by a return spring 26 formed of a torsion spring mounted on a support shaft 25, and is held at a position shown in FIG.

Here, when a voltage is applied to the electromagnetic coil 23 as an external trip command, the movable magnet 22
Is attracted to the fixed magnet 21, and accordingly, the trip lever 24 is rotated clockwise against the return spring 26. The pivoted trip lever 24 hits the operating piece 18 meshing with the arm 24b to rotate the trip crossbar 13 counterclockwise. As a result, the contact end 11a of the latch receiver 11 is disengaged from the claw 14 of the trip crossbar 13 as described above, and the circuit breaker is shut off.

Reference numeral 27 denotes a microswitch for releasing the excitation of the electromagnetic coil 23 at the time of completion of the trip operation of the circuit breaker to prevent its burning, and is operated by an actuator 28 for detecting the trip position of the tripping mechanism. Electromagnetic coil 23
Is released, the movable magnet 22 and the trip lever 24 are returned to the illustrated state by the action of the return spring 26.

FIG. 7 shows a state before the arm 24b of the trip lever 24 comes into contact with the operating piece 18. In this state, the contact end 11a of the latch receiver 11 is displaced by k and the trip crossbar 13 is moved. Abut on the claw 14 of the occupant. FIG. 8 shows a state at the moment when the trip lever 24 rotates the trip cross bar 13 and the contact end 11 a of the latch receiver 11 comes off the claw 14. At that point, arm 24b of the trip lever 24, the rotation radius from the center of the support shaft 15 of the actuating piece 18 is allowed to act a force on a point P ₀ of the H _0. This point P ₀ is substantially stationary during the trip operation, and therefore, the turning radius H ₀ is also substantially constant.

FIG. 9 shows the attraction stroke of the movable magnet 22 in the process of the trip operation by the voltage trip device 17, the force (trip load) received by the movable magnet 22 from the trip lever 24 and the attraction force generated by the electromagnetic coil 23. FIG. 7 is an operation characteristic diagram showing the relationship of FIG. In the figure, the trip load acting on the movable magnet 22 started to be attracted from the point of the stroke S ₀ gradually increases as the return spring 26 is deformed, and the arm 2 of the trip lever 24 is moved.
4b increases rapidly at the point of the stroke S ₁ of the moment striking the operating piece 18. This rapid increase is mainly due to the latch receiver 11 and the claw 1
4 due to the frictional force. This trip load gradually increases as the deformation load of the back spring (not shown) of the return spring 26 and the trip crossbar 13 increases, and the stroke S at which the latch receiver 11 comes off the pawl 14 is increased.
Drops sharply at point ₂ . Thereafter, only the deformation load of the return spring 26 is applied, and the load gradually increases, and the movable magnet 22 ends up being attracted to the fixed magnet 21. On the other hand, the attraction force increases as the attraction of the movable magnet 22 advances and approaches the fixed magnet 21.

[0011]

By the way, for the attraction of the movable magnet 22 for performing the above-mentioned trip operation, the trip crossbar 13 is provided with a necessary and sufficient tripping force (driving torque) and rotation amount. Suction force and stroke are required. In that case, the turning radius H of the operating piece 18
_{If 0 is set} to a large _value , a large tripping force can be obtained with the same suction force, but on the other hand, the required stroke also increases. Therefore conventionally defines the size of the H ₀ in consideration of the balance between the required suction force and stroke.

On the other hand, recently, circuit breakers have been downsized,
Since the installation space of the voltage trip device 17 is also small, it is difficult to increase the size of the electromagnet and allow the movable magnet 22 to have a sufficient attractive force. As a result, as shown in FIG. 9, there may be a case where the trip load exceeds the suction force and the trip cannot be performed due to the variation in the accuracy of the components, and a lot of man-hours are spent for the adjustment.
In that case, the trip load cannot be easily reduced because it is related to the basic characteristics of the circuit breaker. Therefore, a voltage trip device having a sufficient tripping force even in a small size is desired. SUMMARY OF THE INVENTION An object of the present invention is to provide a voltage trip device for a circuit breaker having a sufficient trip force without increasing the size of an electromagnet.

[0013]

In order to achieve the above-mentioned object, the present invention provides a method of making a contact between a trip lever and an operating piece shift from a point having a large turning radius of the operating piece to a point having a small turning radius during the trip operation. It is configured so that In this case, it is more advantageous to reduce the size of the electromagnet if the time when the turning radius of the operating piece shifts from a large point to a small point is the moment when the trip mechanism by the trip crossbar is unlocked.

[0014]

In the present invention, at the beginning of the trip operation, the trip lever comes into contact with a point having a large turning radius of the operating piece,
The contact point between the trip lever and the operation piece is divided into two stages so that the contact point between the trip lever and the operating piece is brought into contact with a point having a small radius of rotation when the movable magnet has been attracted to some extent. That is, at the start of a trip operation with a small suction force, the trip lever is brought into contact with a point of a large turning radius of the operating piece to generate a large tripping force. However, a sufficient amount of rotation cannot be given to the trip crossbar 13 as it is, so that at a stage where the attraction of the movable magnet has progressed to some extent, the contact point is moved to a point where the turning radius of the operating piece is small so as to obtain a large amount of rotation. I do. When the radius of rotation is small, a large attractive force is required. However, at this stage, there is no problem because the movable magnet approaches the fixed magnet and the attractive force is increased.

In this case, the time when the contact point between the trip lever and the operating piece shifts to a point where the turning radius of the operating piece is small is determined at the moment when the trip mechanism is unlocked by the trip crossbar (the latch receiver is released from the pawl). If this is the case, the trip crossbar can be driven with a large turning radius through a lock with a large trip load, and the electromagnet can be made smaller.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Here, FIG. 1 is a side view of a main part of the voltage trip device showing a state at the start of a trip operation, FIG. 2 is a side view of a main part showing a state in the middle of the trip operation, and FIG. 3 is an operation characteristic diagram. Note that the same reference numerals are used for the portions corresponding to the conventional example, and the description of the same portions is omitted. 1 and 2, the operating piece 18 of the trip cross bar 13 has an inclined surface 29 formed on the side of the trip lever 24 that meshes with the arm 24a, and when the trip operation is started, as shown by a chain line in FIG. arm 24b is adapted to push the operating piece 18 through the point contact with the P ₁ point in the upper corner portion of the inclined surface 29 of the actuating piece 18, until some time. Then, when the trip operation proceeds and the contact end 11a of the latch receiver 11 comes off the claw 14 of the trip cross bar 13 (at the time of the engagement k = 0), the operating piece 18a is inclined as shown in FIG. in contact with the P ₂ points lower corner of the surface 29,
Thereafter, the end of the stroke of the movable magnet 22 is directly reached.

Here, the support shaft 1 of the trip crossbar 13
Rotation radius H ₁ from the center of the 5 to P ₁ point is greater than the rotation radius H ₀ in the prior art, also the rotation of up to _two points P radius H ₂
Is smaller than the turning radius H ₀ . Therefore, if the tripping force required for the trip crossbar 13 is the same, the trip load acting on the movable magnet 22 becomes smaller than before, and the remaining power for the attraction force increases. However, if the turning radius of the operating piece 18 remains large, the stroke of the movable magnet 22 becomes insufficient for the required amount of rotation of the trip crossbar 13. So, trip crossbar 1
3 the moment the tripping the locking mechanism is released by, namely a large rotation amount can be obtained with a smaller stroke than the conventional transferred to the contact point to a small point P ₂ of the rotation radius at the moment the latch receiver 11 is disengaged from the pawl 14 I'm doing well.

FIG. 3 is an operation characteristic diagram showing the above-mentioned relationship based on the same suction force and stroke as in the conventional example. In the drawing, the trip load acting on the movable magnet 22 that has started to be attracted at the point of the stroke S ₀ increases sharply at the point of the stroke S ₁ at which the arm 24 b of the trip lever 24 hits the point P _{1 of the} operating piece 18. However, the trip load at this point is smaller than in the conventional example and does not exceed the suction force. Trip load was then gradually increased, the latch receiver 11 is sharply in terms of the stroke S ₄ which deviate from the pawl 14, leads to the termination then with again increasing.

[0019] Since the latch receiver the time in the above embodiment the contact point is shifted to _two points P 11 is a point deviating from the pawl 14, from the stroke S ₁ of a large trip load such S
_The trip load becomes smaller than the conventional example throughout the period up to _4, and the size of the electromagnet can be reduced. Although the stroke S ₄ point since it moves the contact point on the P ₂ points to obtain the necessary amount of rotation of the trip cross bar 13 in the rest of the stroke, the movable magnet 22 because the trip load case only spring load The stroke ratio of the trip crossbar 13 to the stroke of the movable magnet 22 can be made sufficiently large, so that the stroke amount required for the movable magnet 22 can be reduced, and the size of the electromagnet in the front-rear direction can be reduced. Instead harm even contact point a point of time a little more before the stroke S ₃ to shift to the P ₂ points (Fig. 3), in which case the reviews loads the instant the contact point is shifted as shown by broken lines in FIG. Increase. However, at that time, there is no problem because the suction force is increased.

[0020]

According to the present invention, the contact point between the trip lever and the operating piece shifts from a point having a large radius of rotation of the operating piece to a point having a small rotating radius in the course of the trip operation. Since the trip load can be reduced at the beginning of the trip operation with a small suction force, there is no danger of trip failure due to insufficient suction force, and when the suction force increases, the rotation ratio of the trip crossbar to the stroke of the movable magnet increases. Therefore, the required rotation amount of the trip crossbar can be secured with a small stroke. In particular, it is effective to reduce the size of the electromagnet if the time when the contact point is shifted is the time when the trip mechanism using the trip crossbar is unlocked.

[Brief description of the drawings]

FIG. 1 is a main part side view showing a state at the time of starting a trip operation of a voltage trip device according to an embodiment of the present invention.

FIG. 2 is a main part side view showing a state during a trip operation of the voltage trip device of FIG. 1;

FIG. 3 is an operation characteristic diagram of the voltage trip device of FIG. 1;

FIG. 4 is a vertical sectional view of a circuit breaker provided with a conventional voltage trip device.

FIG. 5 is a plan view of the voltage trip device in FIG. 4;

FIG. 6 is a side view of FIG. 5;

7 is a main part side view showing a state at the time of starting a trip operation in the conventional example of FIG. 6;

8 is a main part side view showing a state during the trip operation of the conventional example of FIG. 6;

9 is an operation characteristic diagram of the conventional example of FIG.

[Explanation of symbols]

11 latch receiver 13 reviews cross bar 14 claw 17 voltage tripping device 18 operating piece 22 movable magnet 24 trip lever H ₁ turning radius H ₂ rotation radius P ₁ contact point P ₂ contact points

Claims (2)

(57) [Claims] A tripping lever is driven by attracting a movable magnet in response to an external command, and a tripping bar is engaged with the tripping bar so as to trip the circuit breaker to trip the circuit breaker. A device for tripping a voltage of a circuit breaker, characterized in that the contact point between the trip lever and the operating piece shifts from a point having a large radius of rotation of the operating piece to a point having a small turning radius during the trip operation. . 2. The time when the contact point between the trip lever and the operating piece shifts from a point where the turning radius of the operating piece is large to a point where the turning radius is small is defined as the moment when the trip mechanism by the trip crossbar is unlocked. The circuit tripping device according to claim 1, wherein: