CN1276453C - Electromagnetic tripping apparatus in circuit breaker - Google Patents

Description

Electromagnetic trip unit in circuit breaker

technical field

The invention relates to an electromagnetic tripping device in a circuit breaker, which can be used in automatic circuit breakers, earth leakage circuit breakers and the like.

Background technique

First, using the above-mentioned automatic circuit breaker as an example, the structure of the circuit breaker related to the subject matter of the embodiment of the present invention is shown in FIG. 3 . In this figure, reference numeral 1 represents the circuit breaker housing, reference numeral 2 represents the power terminal, reference numeral 3 represents the fixed contact, reference numeral 4 represents the movable contact, reference numeral 5 represents the contact opening/closing mechanism, and reference numeral 6 represents the opening/closing mechanism. The operating handle, the symbol 7 represents the electromagnet unit of the overcurrent tripping device, the symbol 8 represents the trip bar connected with the electromagnet unit 7, and the symbol 9 represents the connection between the contact opening/closing mechanism 4 and the trip bar 8 The latch receiver forming a connection between them, and reference numeral 10 denotes a load terminal, and the electromagnetic coil 11 of the electromagnet unit 7 is fitted between the load terminal 10 and the movable contact 4, and then connected to the main circuit.

In addition, as shown in FIG. 4, the above-mentioned electromagnet unit 7 includes: an electromagnetic coil 11; an oil-buffered coil core 12 inserted into the electromagnetic coil 11 and having a downwardly oriented contact end piece 12a; an L-shaped yoke 13; A rocker type armature 14 swingably hinged at the lower end of the yoke 13; and an operating arm 14a bent into an L-shape from the rear end of the armature 14 to the rear of the yoke 13; after these parts are assembled in the unit case 15 , they are installed in the circuit breaker housing 1 in Fig. 3.

The operation of such circuit breakers is well known. In the ON state shown in the figure, the main circuit current flows from the power terminal 2 to the load side through the fixed contact 3, the movable contact 4, and the electromagnetic coil 11 of the electromagnet unit 7. At this time, the operating handle 6 is pushed down to the OFF position, and the opening/closing mechanism 5 moves the movable contact 4 to the OFF position. Then, when the overcurrent flows in the main circuit, due to the attracting action of the electromagnet unit 7, the armature 14 is attracted to the contact end piece 12a, and the operating arm 14a provided on the armature 14 swings to the disengagement position shown in FIG. The trip arm 8 a of the trip rail 8 abuts, thereby releasing the connection between the trip rail 8 and the latch receiver 9 . As a result, the contact opening/closing mechanism 5 performs a tripping action to disengage the movable contact 4, thereby cutting off the main circuit current.

Next, the connecting action between the armature 14 and the trip bar 8 during the above-mentioned attracting action of the electromagnet unit 7 will be described with reference to FIGS. 5( a ) to 5 ( d ). First, Fig. 5(a) shows a stable state, wherein the circuit breaker is in the OFF state or the rated current flows through the main circuit, and the armature 14 of the electromagnet unit 7 is returned to the contact terminal piece by the elastic force of the return spring 16 12a at a distance of (gap length g). Furthermore, in this stable state, a space is formed between the operating arm 14a extending upward from the rear end of the armature 14 and the trip arm 8a facing the operating arm 14a and protruding downward from the trip bar 8, and the latch The connecting piece 9a of the receptacle 9 abuts against the claw 8b on the trip bar 8 and remains in this position. The trip cross bar 8 is elastically biased on the waiting position shown in the accompanying drawings by a return spring (not shown in the figure), and the latch receiver 9 is elastically biased in the counterclockwise direction, and its upper end constitutes a swing fulcrum .

On the other hand, when an overcurrent flows in the electromagnetic coil 11 of the electromagnet unit 7, the armature 14 is attracted to the contact terminal piece 12a due to the electromagnet attraction force, as shown in FIGS. 5(b) and 5(c). As shown, and corresponding to this movement, the operating arm 14a swings in the counterclockwise direction, and the hinge point O serves as a fulcrum, so that the arm end of the operating arm 14a collides with the tripping arm 8a of the tripping crossbar 8, thereby pushing in the clockwise direction Trip cross bar 8. A point of contact force (point of application of force) at a collision point between the trip arm 8a and the end of the operation arm 14a is indicated by symbol P. As shown in FIG. After the state shown in Figure 5(c), when the armature 14 is in the state of being attracted to the contact end piece 12a, as shown in Figure 5, the connecting piece 9a of the latch receiver 9 and the claw 8b of the trip bar 8 The connection between them ends, and the latch receiver 9 swings counterclockwise due to the action of the bias spring, thereby releasing the latch of the contact opening/closing mechanism. As a result, the opening/closing mechanism performs a tripping action, and the movable contact 4 is disengaged, thereby cutting off the main circuit current.

In this regard, in promoting the miniaturization of circuit breakers and reducing power consumption, when a small, small-capacity electromagnet is used instead of an electromagnet that takes up a large space, the electromagnetic tripping device used in the above-mentioned prior art will There arises a problem that the tripping operation of the circuit breaker becomes unstable as described below.

In other words, in the characteristic curve of Fig. 2 (which is based on the data of actual tests done by the inventor and others), A indicates that when 200% of overcurrent flows in a large rated capacity electromagnet (330AT) When the attraction characteristic curve, and B represents the attraction characteristic curve when 200% overcurrent flows in a small rated capacity electromagnet (200AT). As is well known, the attractive force of the electromagnet is inversely proportional to twice the gap length g (Fig. 5(a)) between the armature and the contact end pieces.

Therefore, for the electromagnetic trip device in Fig. 5, when the trip bar 8 is driven from the waiting position to the release position due to the attractive force of the electromagnet unit 7, the amount of load is accepted as a self-spring biased latch 9 and the trip bar 8, a torque acting on the armature 14 through the trip arm 8a and the operating arm 14a adjacent to the end of the trip arm 8a (at the point of contact force P), the load (resisting electromagnetic The magnetic attraction force of the body and the force that makes the armature leave the contact end piece) has a characteristic curve represented by the symbol C. Furthermore, in this example, the return spring 16 of the armature also acts as a load (5g).

In this way, if an electromagnet with a large rated capacity is used as the electromagnet unit 7, the attractive force (characteristic curve A) is greater than the load capacity of the armature (characteristic curve C), which means that the trip bar 8 can be driven to the release position without difficulty . Therefore, when an electromagnet with a small rated capacity is used in order to support and promote the miniaturization of the circuit breaker as described above, its attraction characteristic curve B and armature load capacity characteristic curve C are in the region C1 (indicated by oblique lines in the figure). ) at the intersection (corresponding to the state in Figure 5(b)), in this region, the load of the armature exceeds the attractive force of the electromagnet. Therefore, sometimes the armature of the electromagnet hangs in this position, and tripping of the circuit breaker is not possible without further pushing the trip arm of the trip bar.

Therefore, when using an electromagnetic trip device having a conventional structure, it is problematic to use a small, small-capacity electromagnet in the electromagnet unit in order to miniaturize the circuit breaker.

Contents of the invention

In view of this, an object of the present invention is to provide an improved electromagnetic tripping device in a circuit breaker, when the trip bar is driven by the attracting action of the electromagnet unit, as an action on the armature of the electromagnet. The load (work) of the reaction force is reconfigured to conform to the attraction characteristic curve of the electromagnet, effectively generating the attraction force of the electromagnet with a small rated capacity, thereby performing a stable tripping action.

In order to achieve the above object, according to the present invention, there is provided an electromagnetic tripping device of a circuit breaker, which operates when an overcurrent in the main circuit is detected, and makes the main circuit contact The on/off mechanism performs the tripping action, which includes an electromagnet unit that performs an attracting action when an overcurrent is detected, the operating arm on the rocker-type armature of the electromagnet unit and the tripping crossbar The trip arms face each other, receiving the attractive force during the action of the electromagnet unit, and the operating arm, which swings with the armature, pushes the trip arm of the trip crossbar, thereby releasing the latch receiver and causing the opening/closing mechanism to perform a Tripping action, in which the point of contact force of the operating arm and the tripping arm changes in steps along the longitudinal direction of the operating arm, thereby cooperating with the change in the length of the gap between the armature and the contact end piece during the attracting action of the electromagnet unit ; where the load applied to the armature is reduced by setting the contact force point on the base side of the operating arm in the first half of the attraction action (where the gap length is large), while in the second half of the attraction action (where the gap length is Small) Move the point of contact force to the end side of the manipulator arm. A specific aspect of the electromagnetic trip device of the circuit breaker is that the operating arm provided on the armature of the electromagnet unit and the trip arm provided on the trip bar extend from opposite directions so as to face each other, when the operating arm In the case of a straight arm, a stepped portion changing in a step shape is formed on the trip arm on the side facing the operating arm along the longitudinal direction of the trip arm.

According to the above structure, when the trip bar is driven to the release position in the attracting action of the electromagnet unit, in the first half of the attracting action (the gap length between the armature and the contact end piece is large and the electromagnetic attractive force is small) , the point of contact force between the operating arm and the tripping arm of the tripping bar is located on the base side of the operating arm, which means that the torque applied by the tripping bar to the armature of the electromagnet unit is kept low according to the principle of leverage. Therefore, even if the electromagnet is a small-capacity electromagnet with a relatively small attractive force, the trip arm of the trip crossbar can be pushed to the release position by the operating arm without suspending the armature halfway.

On the other hand, when the attracting action of the armature continues and the gap length decreases, the inclination angle of the operating arm connected to the armature changes, and the contact force point where the operating arm adjoins the tripping arm moves to the end of the operating arm. Therefore, when the torque applied to the armature from the side of the trip bar becomes larger and the gap length of the armature becomes smaller, the attractive force of the electromagnet also increases, and the trip bar can be driven to the final position without difficulty.

In other words, by varying the point of contact force between the aforementioned operating arm and the tripping arm in the longitudinal direction of the operating arm in order to cooperate with the change in the length of the gap between the armature and the contact end piece during the attracting action of the electromagnet unit, Therefore, it is possible to make the armature load equal to the work (force × distance) required to drive the trip bar from the waiting position to the release position consistent with the attractive force characteristic curve of the electromagnet, thereby effectively generating a small rated capacity electromagnetic force. The attractive force of the body makes the circuit breaker perform the tripping action.

As described above, according to the present invention, in the electromagnetic tripping device of the circuit breaker, the operating arm is provided on the rocker armature for the electromagnet unit, and the electromagnet unit performs an attracting action when an overcurrent is detected, thereby tripping The tripping arm of the crossbar and the operating arm face each other, and during the attracting action of the electromagnet unit, the operating arm pushes the tripping arm of the tripping crossbar, thereby causing the opening/closing mechanism to perform a tripping action, wherein the operating The contact force point of the arm and the trip arm changes in steps along the longitudinal direction of the operating arm, so as to cooperate with the change of the gap length between the armature and the contact end piece during the attracting action of the electromagnet unit; wherein, through the attracting action The first half (where the gap length is large) sets the point of contact force on the base side of the operating arm keeping the load applied to the armature low, while the second half of the suction action (where the gap length is small) Move the point of contact force to the end side of the manipulator arm. Therefore, by ingeniously establishing agreement between the attractive characteristics of the electromagnet and the pattern of the amount of load acting on the armature of the electromagnet from the trip bar through the trip arm and the operating arm during the tripping action of the circuit breaker relationship, even if the electromagnet unit uses a small, small-rated-capacity electromagnet, it can effectively generate electromagnet attraction, so that the circuit breaker can reliably perform the tripping action. In this way, in addition to making the electromagnetic tripping device installed in the circuit breaker Miniaturization and providing it with a small capacity also contributes to miniaturization of the circuit breaker and promotes economical use of energy.

Description of drawings

Fig. 1 is an explanatory view showing the structure and tripping action of an electromagnetic tripping device according to an example of the present invention, wherein Figs. 1(a) to 1(d) show different aspects of the tripping action;

Fig. 2 is a characteristic graph, except for the electromagnet attraction force, it has shown the gap length of the electromagnet in the electromagnetic tripping device in Fig. 1 and the prior art and the load capacity of the armature. relation;

Fig. 3 is a cross-sectional view of the construction of a circuit breaker related to the subject matter of the embodiment of the present invention;

FIG. 4 is an exploded perspective view showing an assembled structure of the electromagnet unit in FIG. 3; and

5 is an explanatory view showing the structure and tripping action of an electromagnetic trip device employed in a conventional circuit breaker, wherein FIGS. 5(a) to 5(d) show different aspects of the tripping action.

Detailed ways

Embodiments of the present invention will be described below with reference to the examples shown in FIGS. 1 and 2 . In FIG. 1, the same parts as those in FIG. 5 are denoted by the same reference numerals, and their descriptions are omitted.

The electromagnetic tripping device in the example shown in FIG. 1 is basically the same as that shown in FIG. 5 , but the tripping arm extending downward from the tripping bar 8 and facing the side of the operating arm 14a of the electromagnet unit 7 8a has changed to the shape described below. In addition, FIGS. 1( a ) to 1 ( d ) show the operating states corresponding to FIGS. 5( a ) to 5 ( d ), respectively.

In other words, the arm end of the tripping arm 8a in the example shown in the accompanying drawings faces the operating arm 14a standing upright from the bottom up, and the length of the tripping arm 8a is set to face the longitudinal direction of the operating arm 14a. After the central part (in the traditional structure of Fig. 5, the end of the tripping arm 8a and the end of the operating arm 14a face each other), the stepped portion 8a-1 that changes stepwise in the longitudinal direction is also on the surface of the opposite operating arm 14a. Formed on.

The tripping action using this structure is described below. First, Fig. 1(a) shows a stable state, the armature 14 of the same electromagnet unit 7 in Fig. 5(a) retreats from the contact end piece 12a, and the operating arm 14a is tilted to the right The posture is suspended at the position of the trip arm 8 a apart from the trip bar 8 . In this way, when the overcurrent flows through the main circuit, the attraction action of the electromagnet unit 7 starts, the operating arm 14a swings in the counterclockwise direction, and the hinged part of the armature 14 serves as the fulcrum O, thereby being in the position shown in Fig. 1(b) position, and the middle portion (central portion) of the operating arm 14a collides with and pushes the end of the trip arm 8a. In this case, the contact force point between the operating arm 14a and the trip arm 8a is P1, and the torque acting on the armature 14 from the trip bar 8 through the operating arm 14a is exerted on the contact force point P1. The product of the force (reaction force) and the distance from the fulcrum O of the operating arm 14a to the contact force point P1.

On the other hand, when the attracting action of the electromagnet continues and the inclination angle of the operating arm 14a is changed due to the armature 14 being attracted to the position shown in FIG. The point moves to the above-mentioned step portion 8a-1, and the point of contact force between the operating arm 14a and the trip arm 8a moves from P1 to P2. When this state appears, the moment acting on the armature 14 by the trip bar 8 through the operating arm 14a is the product of the force applied to the contact force point P2 and the distance from the fulcrum of the armature 14 to the contact force point P2, and Compared with Fig. 1(b), the load has increased. When the armature 14 is fixed on the contact end piece 12a as shown in Figure 1(d), the connection between the connecting piece 9a of the latch receiver 9 and the claw 8b of the trip cross bar 8 is similar to that in Figure 5(d) ) is terminated in the same manner, and the latch receiver 9 is swung in the counterclockwise direction due to the bias spring, thereby releasing the latch of the contact opening/closing mechanism. As a result, the opening/closing mechanism performs a tripping action, and the main circuit current is cut off.

Here, the characteristic curve D is obtained when the load amount of the armature due to the above-mentioned attracting action is plotted and displayed in the characteristic graph in FIG. 2 . Points D1 and D2 on the characteristic curve D correspond to the states in Figs. 1(b) and 1(c), respectively. It can be seen that the load of the armature corresponding to the gap length g between the armature and the contact end piece changes stepwise as shown in the figure. In the first half of the suction action (contact force point P1) with a large gap length g, the load of the armature small, and in the second half of the attraction action (contact force point P2) where the gap length g decreases, the load increases, and according to this stepped load pattern, the trip bar 8 is driven due to the attraction action of the electromagnet unit 7 to the release position. In addition, by keeping the load of the armature low in the first half of the attracting action, even when an electromagnet with a small rated capacity is used, the attractive force characteristic curve (line B) and the load characteristic curve (line D) will not change. Intersecting halfway, although the load increases in the second half of the attraction action, since the attraction force of the electromagnet also increases, the trip bar can be driven to the final position without difficulty.

In addition, the present invention is not limited to the structures of the examples shown in the drawings. Although in the example shown in the drawings, a stepped portion for setting the contact force points P1 and P2 is formed on the trip arm 8a, such a stepped portion may also be formed on the operating arm 14a. In addition, the set number of contact force points can also be divided into three or more points, so as to match the attraction characteristic curve of the electromagnet.

Claims (2)

1. the electromagnetic tripping apparatus of a circuit breaker, work during its overcurrent in detecting main circuit, and make the action of carry out threading off of the open/close mechanism of main circuit contact by a dropout cross bar and a breech lock recipient, wherein, comprise that one carries out the electromagnet unit that attracts action when detecting overcurrent, motion arm on the rocker-type armature of this electromagnet unit and the trip arm that is arranged on the dropout cross bar face one another, in the electromagnet unit course of action by accepting this attraction, the described motion arm of swinging with armature promotes the trip arm of dropout cross bar, thereby latch recipient, make open/close mechanism carry out a dropout action

It is characterized in that the force that contacts of described motion arm and the trip arm becomes stairstepping to change along the longitudinal direction of motion arm, thus in the attraction course of action of electromagnet unit with between armature with contact the variation cooperation of the gap length between the dististyle; Wherein, by at the first half that attracts action, wherein gap length is bigger than the gap length in the latter half that attracts action, and will contact the force and be set in the base portion side of motion arm and reduce the load that imposes on armature; And at the latter half that attracts action, wherein gap length is littler than the gap length in the first half that attracts action, and will contact the end side that the force moves to motion arm, to drive the trip arm of dropout cross bar.

2. the electromagnetic tripping apparatus of circuit breaker as claimed in claim 1, it is characterized in that, the trip arm that is arranged on the motion arm on the armature of electromagnet unit and is arranged on the dropout cross bar is configured to extend in opposite direction and faces one another, when motion arm is a linear arm, become on ladder part that stairstepping changes is formed at the trip arm in the face of motion arm one side along the longitudinal direction of the trip arm.

Images