WO2008049336A1

WO2008049336A1 - Circuit breaker for rapidly breaking low voltage circuit

Info

Publication number: WO2008049336A1
Application number: PCT/CN2007/003032
Authority: WO
Inventors: Dongwen Xie
Original assignee: Zhejiang Chint Electrics Co., Ltd
Priority date: 2006-10-25
Filing date: 2007-10-24
Publication date: 2008-05-02
Also published as: CN101170031A; CN101170031B

Abstract

A circuit breaker for rapidly breaking low voltage circuit. The circuit breaker drives with expulsive force to cut off an execution unit rapidly to realize overload and short circuit protection. The circuit breaker includes a plastic casing, a moving contact, a static contact, an explosion chamber, an operating mechanism for breaking and closing the circuit, and a release mechanism for controlling tripping. The circuit breaker further includes an execution unit that can realize rapid breaking and current limiting. The execution unit has a passive part and an active part. When the current passing though the moving contact and the static contact exceeds a predetermined threshold, the expulsive force caused by the current drives the moving contact and the static contact to detach from each other. The detachment action directly drives the passive part and the active part, wherein the action of the active part causes a release lever to release, thereby directly driving the circuit breaker to trip.

Description

Fast breaking low voltage circuit breaker

The present invention relates to a plastic case type low voltage circuit breaker, and more particularly to a low voltage circuit breaker having a quick breaking and current limiting function for implementing overload and short circuit protection. Background technique

A generally known molded case circuit breaker or automatic switch having a breaking function, which may include one or more standard single electrodes installed in a common molded casing, according to the type of current and power equipment required by the user, for example Dipole, tripolar or quadrupole. The circuit breaker is mainly composed of a sensing mechanism, a transmitting mechanism and an actuator. The sensing mechanism, such as an overcurrent release, can sense abnormal conditions in the circuit and command signals issued by the operator or the relay protection system, and the actuator consisting of the movable and static contacts and the arc extinguishing chamber through the transmission mechanism Perform the on or off task of the circuit breaker. Each of the circuit breakers has a pair of moving and static contacts that are forced to contact in the closed position of the circuit breaker by elastic means, wherein the ends of the static contacts are U-shaped near the ends of the contacts to form moving and static contacts. The structure in which the current direction is opposite in the vicinity of the contact point makes the contact structure formed by the movable contact and the fixed contact conform to the condition that the current direction is opposite. Then, when the current flowing through the moving and stationary contacts exceeds a predetermined threshold, the moving contact is rapidly dissipated from the position in contact with the fixed contact by using the electric repulsion generated by the current, thereby achieving the limiting current and The purpose of security protection. The circuit breaker also has a trip trip device that has an overload and/or short circuit fault detector that activates the circuit breaker's automatic disconnect operating mechanism in the event of a fault.

With the increase of the capacity of low-voltage power grids in China and the improvement of the performance of low-voltage electrical appliances, the industrial and civilian demand for circuit breakers is increasing rapidly. In particular, it is necessary to develop plastics with compact structure, small size, light weight, long life, safe use and high performance. Shell low voltage circuit breaker. At present, most of the existing circuit breakers use the electromagnetic force or the anti-time limit action characteristics of the bimetal to strike the tripping rod to complete the breaking task. Due to the slow operation of the bimetal and the electromagnetic system, the breaking mechanism is delayed in starting, so that the arc formed between the contacts is burned for a long time, so that the contacts are easily eroded, and the current limiting capability is weak, the breaking time is long, and the breaking ability is low. Chinese Patent No. 92111503.2 provides an improved molded case type low voltage circuit breaker which adopts a pneumatic breaking principle, that is, a high voltage rapidly formed in a sealed arc extinguishing chamber by an arc when the moving and static contacts are disengaged. The gas, the tripping lever is tripped, so that the circuit breaker can be quickly disconnected. Since the circuit breaker must have a relatively closed arc extinguishing chamber, the cavity of the arc extinguishing chamber is arranged in the form of a cylinder matched with a piston equipped with a trip control lever, so that the time and cost of manufacturing the circuit breaker is increased, so this form The circuit breaker is difficult to manufacture, expensive, and the breaking speed and current limiting capability are not ideal. Summary of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel circuit breaker having a structural unit, a low cost, an easy manufacturing, a good current limiting effect, a high breaking speed, and high safety and reliability.

In order to achieve the above object, the quick disconnecting circuit breaker of the present invention employs the following technical solutions:

The invention provides a low-voltage circuit breaker, which has a plurality of standard single-pole breaking devices installed in one molded case with one or more poles, and drives the circuit breaker operating mechanism in the event of an overload or short-circuit fault common to all single-pole devices. Tripping trip mechanism comprising a trip bar, wherein each single-pole breaking device comprises a static contact fixedly mounted in the arc extinguishing chamber; a moving contact pivotally mounted on the large shaft of the operating mechanism through the small shaft; The circuit breaker operating mechanism performs a breaking or closing action of the moving contact and the static contact; an elastic device mounted on the large shaft can force the moving contact to reliably contact the stationary contact. The circuit breaker of the present invention further includes an execution unit that performs a fast breaking task, and one end of the execution unit has an integrally extended passive member (passive contact arm 111; cam arm 151), and the passive member (passive contact arm) 111; the cam arm 151) can contact the movable contact arm integrally extending from the tail of the driven contact; the other end of the execution unit has an integrally extended active member (the active contact arm 112; the push rod contact arm 141) The active member (active contact arm 112; push rod contact arm 141) can contact the trip lever. When the current flowing through the moving and stationary contacts exceeds a predetermined threshold, the electric power generated by the current overcomes the elastic force of the elastic device, and drives the movable contact to drive the passive member of the executing unit during the repelling action ( Passive contact arm 111; cam arm 151) action, said passive The action of the member drives the active member (active contact arm 112; push rod contact arm 141) of the execution unit to act, and the action of the active member drives the tripping rod of the trip device to move. The action causes the poles of the circuit breaker to be simultaneously disconnected, so that the tripping operation of the circuit breaker is quickly performed by directly driving the trip device by the disengaging action of the moving contact generated by the electric power through the mechanical transmission mode.

The circuit breaker of the invention adopts the mechanical breaking principle, that is, the action of the tripping rod is directly driven by the dynamic and static contact disengagement action. Obviously, compared with the prior art which adopts the principle of electromagnetic breaking or pneumatic breaking and the mechanism, the circuit breaker of the invention has faster breaking speed, good breaking reliability, simple structure, easier manufacture, low cost, long service life and limitation. The flow effect is good and the safety protection performance is strong. DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a three-dimensional perspective view of a circuit breaker of the present invention.

Fig. 2 is a three-dimensional perspective view showing the cam type breaking mechanism of the circuit breaker according to the first embodiment of the present invention.

Fig. 3 is a view showing the structure of a cam of a key component of the cam type breaking mechanism of the circuit breaker according to the first embodiment of the present invention.

Fig. 4 is a three-dimensional perspective view showing an eccentric breaking mechanism of the circuit breaker according to the second embodiment of the present invention.

Fig. 5 is a view showing the structure of a key portion eccentric wheel of the eccentric wheel breaking mechanism of the circuit breaker according to the second embodiment of the present invention. detailed description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the quick-breaking circuit breaker of the present invention will be specifically described with reference to the accompanying drawings, but the circuit breaker of the present invention is not limited to the following embodiments.

As shown in FIG. 1, the circuit breaker of the present invention comprises a plastic outer casing 21, an arc extinguishing chamber 19, an operating mechanism 20 composed of a stationary contact 10, a movable contact 13 and a large shaft 18 for performing circuit breaking/closing, The trip mechanism composed of the trip lever 16 and the like further includes a mechanical quick breaking mechanism composed of the stationary contact 10, the movable contact 13, the cam 15, and the push rod 14. As shown in FIG. 1, the terminal of the stationary contact 10 is disposed outside the arc extinguishing chamber 19, and one end of the contact is installed in the arc extinguishing chamber 19. The stationary contact 10 near one end of the contact has a U-shape (not shown) to form a structure in which the current and the static contact are opposite in direction of the contact. The movable contact 13 is disposed in parallel with the stationary contact 10, and the contact thereof is separated from the contact of the fixed contact 10, and the current direction near the contact is opposite to the current direction of the static contact 10, when flowing through the contact When the current exceeds the predetermined threshold, the electric repulsion generated between the movable contact 13 and the fixed contact 10 can automatically detach the closed moving and static contacts.

As shown in Figs. 1, 2, the movable contact 13 is pivotally coupled to the large shaft 18 of the operating mechanism via the small shaft 17, and is rotatable about the small shaft 17. A cam 15 is pivotally coupled to the large shaft 18 of the operating mechanism via a support shaft 22 and is rotatable about a support shaft 22 on the large shaft 18. The tail of the movable contact 13 is provided with a movable contact arm 131 capable of rotating the follower contact 13 around the small shaft 17. When the movable contact 13 is disengaged, the movable contact arm 131 rotates with the movable contact 13, and touches the cam The cam contact arm 151 of 15 rotates.

As shown in Figure 1-3, the trip mechanism common to all monopole devices consists of components such as trip levers 16. When the trip lever 16 is touched by the push lever contact arm 141, the tripping mechanism of the circuit breaker can be tripped, and all the circuit blocks of the circuit breaker are simultaneously disconnected. A flange 154 is formed on the non-contact end of the cam 15, and the flange 154 is in contact with a 'push rod 14'. When the cam 15 is rotated about the support shaft 22, the push rod 14 is moved up and down by the combined action of the force of the spring 12 and the flange 154. A pusher contact arm 141 is formed on the other side of the push rod 14 on the side in contact with the cam. When the push rod 14 moves up and down with the cam 15, the push lever 141 touches the trip lever 16 to make the trip. Agency tripping.

The quick breaking process of the circuit breaker of the present invention will now be described with reference to Figs. When the current flowing through the moving and stationary contacts exceeds a predetermined threshold, the electric repulsion generated by the current drives the movable and static contacts to disengage, and the moving contact 13 rotates around the small shaft 17 on the large shaft 18, and the movable contact arm 131 The follower contact 13 rotates to rotate, and drives the cam contact arm 151 to rotate, the rotation of the cam contact arm 151 drives the cam 15 to rotate, the flange 154 on the cam drives the push rod 14 to rise, and the rising action of the push rod 14 drives the push rod When the contact arm 141 moves, the movement of the push rod contact arm 141 causes the trip lever 16 to perform a tripping action, thereby tripping the circuit breaker and disconnecting the pole circuits.

Figure 4 and Figure 5 show another alternative of the breaking mechanism of the circuit breaker of the present invention. Implementation. The present embodiment replaces the cam 15 and the push rod 14 of the previous embodiment with the eccentric wheel 11. Specifically, the actuator of the present invention refers to a mechanical transmission mechanism that transmits the disengagement motion of the movable contact 13 to the trip lever 16 and trips it. In the present embodiment, the eccentric 11 of the actuator unit is pivotally coupled to the large shaft 18 of the operating mechanism via the support shaft 22 and is rotatable about the support shaft 22; the eccentric 11 includes a passive contact arm 111 and a The active contact arm U2, the passive contact arm 111 can contact the movable contact arm 131 on the movable contact 13, the active contact arm 112 can contact the trip lever 16; when the current flowing through the moving and static contacts exceeds a predetermined threshold, the current The generated electric power drives the movable and static contacts to disengage, and rotates the movable contact 13 around the small shaft 17 on the large shaft 18. The movable contact arm 131 rotates with the movable contact 13, and drives the passive contact arm 111 to rotate, passively touching. The rotation of the arm 111 drives the eccentric wheel 11 to rotate, and the rotation of the eccentric wheel 11 drives the active contact arm 112 to drive the trip lever 16 to perform a tripping action, thereby tripping the circuit breaker and disconnecting the pole circuits.

The circuit breaker of the invention skillfully uses the operating mechanism of the original operating mechanism of the circuit breaker to perform the mechanical energy breaking, that is, the action of automatically disengaging the moving and static contacts, directly driving the tripping rod by means of mechanical transmission, and testing It has been demonstrated that the circuit breaker of the present invention has a significant positive effect in terms of breaking speed, reliability, and manufacturing cost as compared with similar circuit breakers of the prior art.

Claims

Rights request

1. A quick-break circuit breaker having a plurality of standard single-pole breaking devices installed in one molded case (21) and a common single-pole breaking device for driving a circuit breaker in the event of an overload or short-circuit fault A tripping mechanism for tripping of the operating mechanism, wherein each of the single-pole breaking devices comprises:

a static contact (10) fixedly mounted in the arc extinguishing chamber (19);

a moving contact (13) pivotally mounted on the large shaft (18) of the operating mechanism (20) via the small shaft (17);

The circuit breaker operating mechanism (20) performs an opening or closing action of the movable contact (13) and the stationary contact (10);

The trip mechanism includes a trip lever (16);

A resilient means mounted on the large shaft (18) forcing the movable contact 13 into contact with the static contact 10;

It is characterized by:

Also included is an execution unit that performs a fast breaking task, one end of the execution unit having an integrally extending passive member (111; 151), the passive member (111; 151) being capable of contacting a driven contact (13) a movable contact arm (131) integrally extending from the tail; the other end of the execution unit has an integrally extending active member (112; 141), and the active member (112; 141) can contact the trip lever (16) ) ;

When the current flowing through the moving and stationary contacts exceeds a predetermined threshold, the electric power generated by the current overcomes the elastic force of the elastic device, and drives the movable contact (13) to touch the actuator when the retracting action is performed. The passive member (111; 151) acts, the action of the passive member drives the active member (112; 141) of the execution unit, and the action of the active member touches the tripping lever of the trip device (16) Action, the action of the tripping lever (16) causes the poles of the circuit breaker to be disconnected at the same time, thereby directly driving the tripping device by the disengaging action of the moving contact (13) generated by the electric power by mechanical transmission. Buckle operation.

2. The circuit breaker of claim 1 wherein:

The actuator unit has an eccentric 11 pivotally connected via a support shaft 22 On the large shaft 18 of the operating mechanism,

On the eccentric 1 1 there is an integrally extending active contact arm 112 and an integrally extending passive contact arm 1 1 1 , which respectively constitute an active part and a passive part of the execution unit,

The active contact arm 112 can contact the trip lever 16 of the trip mechanism, and the passive contact arm 1 1 1 can contact the movable contact arm 131 extending integrally from the tail of the movable contact 13 when the movable contact 13 is While the repulsion action is performed, the movable contact arm 131 extending integrally thereon is driven to swing, and the passive contact arm 111 is driven to swing, thereby driving the swing of the active contact arm 112, driving the trip lever 16 to operate and disconnecting the circuit breaker;

The movable contact arm 131 and the movable contact 13 are fixedly connected in the same body or in separate bodies, and the active contact arm 112, the passive contact arm 111 and the eccentric wheel 11 are fixedly connected in the same body or in separate bodies.

3. The circuit breaker of claim 1 wherein:

The actuator unit includes a cam 15 and a push rod 14.

The cam 15 is pivotally coupled to the large shaft 18 of the operating mechanism via a branch 7|shaft 22,

At one end of the cam 15, there is an integrally extending cam arm 151 which constitutes an active member of the actuator unit, and the cam arm 151 is capable of contacting a movable contact arm 131 integrally extending from the tail of the movable contact 13.

On the other end of the cam 15, there is a flange 154 which is engageable with the push rod 14 and which, when the cam rotates about the support shaft 22, drives the push rod 14 to move.

The push rod 14 has an integrally extending push rod contact arm 141, which constitutes a passive member of the execution unit, and the push rod contact arm 141 can contact the trip rod 16 of the trip device, and the movable contact 13 is swayed by the movable arm 131 which is integrally extended on the smashing action, drives the driving member cam arm 151 to swing, and then drives the cam 15 to rotate, and then drives the push rod 14 to move, and drives the passive member push arm 141. Moving, the movement of the pusher arm 141 touches the trip lever 16 and disconnects the circuit breaker.

The movable contact arm 131 and the movable contact 13 are fixedly connected in the same body or in separate bodies, and the cam arm 151 and the cam 15 are fixedly connected in the same body or in separate bodies.

4. Circuit breaker according to claim 2 or 3, characterized in that the eccentric 11 or cam 15 of the actuating unit is pivotally connected to the large shaft 18 of the operating mechanism via a fulcrum shaft 22.

The circuit breaker according to claim 2 or 3, wherein the support shaft 22 and the large shaft 18 are fixedly connected in a separate body or in a separate body, or the support shaft 22 is identical to the eccentric 11 or the cam 15 .

The circuit breaker according to claim 2 or 3, characterized in that the support shaft 22 and the eccentric wheel 11 or the cam 15 and the large shaft 18 are separate elements.

7. Circuit breaker according to claim 2 or 3, characterized in that the eccentric 1 1 or the cam 15 has at least one elastic element for controlling its resetting, such as a tension spring, a compression spring, a torsion spring, a leaf spring or the like.

8. The circuit breaker according to claim 3, wherein: the push rod 14 is movably supported on the plastic housing 21 or in an element or space that does not affect the normal operation of the operating mechanism and the trip mechanism, the manner of the movable support Such as guide rails, shaft holes.

9. The circuit breaker according to claim 3, wherein the push rod 14 is supported in an elastic support manner in a space that does not affect the normal operation of the operating mechanism and the trip mechanism, such as a tension spring. , compression spring, leaf spring, torsion spring.

10. The circuit breaker of claim 3 wherein: the distance between the points on the flange 154 from the axis of the support shaft 22 is unequal.

11. The circuit breaker of claim 3, wherein: the push rod 14 has at least one return spring 12 that resets the push rod 14 and is in mating engagement with the flange 154, and a push that can contact the trip unit 16 The lever arm 141.

12. The circuit breaker according to claim 2, wherein: when the circuit breaker is in the closed state, the active contact arm 112 or the push rod contact arm 141 is sized to just contact the trip lever 16 and enable them to work normally. Preferably, the passive contact arm 111 or the cam arm 151 is sized to just contact the movable contact arm 131 and allow them to function properly.