JP4759454B2 - Circuit breaker - Google Patents

Description

  This invention is a high-capacity type circuit breaker used in an office or factory, and when a large current flows through an energizing circuit, the circuit is cut off by opening the contact mechanism by a tripping device. It relates to a circuit breaker.

  As a conventional high-capacity type circuit breaker, a movable contact base supporting a movable contact is rotatably supported in a movable frame, and the movable contact base is directed toward a fixed contact carried on the fixed contact base. Further, a toggle mechanism is disposed between the movable frame and the manual operation handle from the drive spring and the link, and the line of action of the spring force of the drive spring is before and after the unstable point of the toggle mechanism. Utilizing the characteristic of being urged away in any direction, the contact state between the fixed contact and the movable contact is urged in the on operation, and the fixed contact and the movable contact in the off operation. There is a structure in which these are separated (see Patent Document 1 and Patent Document 2). In this type of circuit breaker, depending on the magnitude of the current that flows beyond the rated current, a mechanism that cuts off by a bimetal operation when the current is relatively small, and a high speed by an electromagnet operation when the current is relatively large And a mechanism that operates.

  The operation of the conventional circuit breaker will be described with reference to FIGS. FIG. 5 is a longitudinal sectional view of a conventional circuit breaker, FIG. 6 is a plan view of the circuit breaker shown in FIG. 5, and FIG. 7 is a schematic view of a toggle mechanism used in the open / close mechanism of the conventional circuit breaker. As can be seen from FIG. 6, most circuit breakers are circuit breakers for three-phase alternating current, and each of the three poles has a contact mechanism having the same structure and its operating mechanism in parallel. In order to avoid the complexity of the figure, in FIG. 6, reference numerals for the opening / closing mechanism are given only to the poles on both sides.

  In the circuit breaker shown in FIGS. 5 to 7, a casing is constituted by a case 1 and a cover 2 provided thereon, and a circuit breaker switching mechanism 4 is provided in the casing. In the casing composed of the case 1 and the cover 2, a movable frame 7 is rotatably held by a rotation center 7a. A movable contact base 10 is pivotally supported on the movable frame 7 by a support shaft 10a. The movable contact base 10 is urged to rotate with respect to the movable frame 7 by the spring force of the contact spring 32. The movable contact 9 carried on the movable contact base 10 normally contacts the fixed contact 11 carried on the fixed contact base 12 fixed to the case 1 with a constant contact pressure applied by a contact spring 32. ing. On the other hand, a handle 3 protrudes from an opening 2 a formed in the upper part of the cover 2. As shown particularly in FIG. 7, a handle lever 5 integrally attached to the handle 3 is rotatably held on the case 1 by a shaft 6. The upper lever 13 connected to the handle lever 5, the lower lever 14 connected to the movable frame 7, and the pivot shaft 15 that rotatably connects both levers 13, 14 constitute a two-bar link, A drive spring 31 is stretched between the handle lever 5 and the pivot shaft 15 of the two-bar linkage mechanism. The two-link and the drive spring 31 form a toggle mechanism that is biased by the drive spring 31 on either side from the unstable point when the levers 13 and 14 are straight. The upper lever 13 is rotatably connected to the handle lever 5 by a pin 16 provided at the upper end thereof, and the lower lever 14 is rotatable to the movable frame 7 by a pin 17 provided at the lower end thereof. It is connected to.

  When the circuit breaker is manually turned on / off, the operation is performed by operating the handle 3 protruding from the cover 2 constituting the outer shell. By rotating the handle 3 about the shaft 6, the line of action of the spring force of the drive spring 31 exceeds the unstable point where the two-bar link is straight, and the top of the opening / closing mechanism 4 having the toggle mechanism. A two-bar link including the lever 13 and the lower lever 14 works, and is positioned at one end of the opening / closing mechanism 4. The movable contact base 10 for three poles is rotated to rotate the movable frame 7. When the handle 3 is operated in the load side direction (clockwise) from the state shown in FIG. 5 in which the movable contact 9 comes into contact with the fixed contact 11 and the circuit is on, the spring of the drive spring 31 is actuated by the opening / closing mechanism 4. Due to the force, the upper lever 21 rotates counterclockwise about the pin 16 and the lower lever 14 is lifted, so that the movable frame 7 rotates clockwise about the rotation center 7a. As a result, when the movable contact base 10 also rotates in the same direction, the movable contact 9 is separated from the fixed contact 11 as shown in FIG. 7, and the circuit breaker is turned off. When the handle 3 is rotated counterclockwise in the off state, the handle lever 5 rotates in the same manner, and the upper lever 13 rotates clockwise around the pin 16 by the spring force of the drive spring 31 and the lower lever 14 Is moved downward, the movable frame 7 is rotated counterclockwise by the downward movement of the lower lever 14, and the movable contact base 10 is also rotated in the same direction, so that the movable contact 9 contacts the fixed contact 11, and the circuit is turned on. It becomes a state.

As described above, in order to turn on or off the circuit breaker, by moving the handle 3, the action line of the spring force of the drive spring 31 corresponds to the state where the two-bar link is straightened in the opening / closing mechanism 4. The toggle mechanism operates beyond the unstable point, and the two-link of the opening / closing mechanism 4 is rotated about the rotation center 7 a of the movable frame 7 by the force of the drive spring 31. When the movable frame 7 is rotated, the movable contact base 10 is also rotated. When the movable contact 9 comes into contact with or is separated from the fixed contact 11 and becomes in a contact state, it can be energized.
The contact pressure at the time of contact between the movable contact 9 and the fixed contact 11 is generated by a contact spring 32 arranged between the movable frame 7 and the movable contact base 10. The contact spring 32 is interposed in such a manner that the movable frame 7 is urged clockwise and the movable contact base 10 is urged counterclockwise around the pivot shaft to the movable frame 7. The movable contact 9 is urged to rotate in a direction in which the movable contact 9 is pressed against the fixed contact 11. By the pressing force by the contact spring 32, the stability of energization and the contact contact reliability are maintained.

  The overcurrent flowing through the circuit breaker is detected by the operation of the bimetal 21 accompanying the temperature rise in the overload region where a relatively small overcurrent flows, and the electromagnets 22 and 23 in the short-circuit current region where the relatively large overcurrent flows. With this operation, the latch 24 of the opening / closing mechanism 4 is detached with a trip time corresponding to the magnitude of the overcurrent. With the release operation of the latch 24, the movable contact 9 is opened by the action of the two-node link, and is disconnected from the contact with the fixed contact 11, thereby interrupting the overcurrent. As for the number of poles, it has poles corresponding to the number of phases of power distribution (three if it is three-phase power distribution). A mechanism is provided. When an arc is generated, the arc gas blast is guided by the arc extinguishing device 25 as a seed and discharged to the outside.

  In this type of circuit breaker, the contact spring 32 that generates the contact pressure between the movable control point 9 and the fixed contact 11 is hardly covered by the movable frame 7, and the periphery of the contact spring 32 constitutes the outer shell. 2 is exposed. When a circuit breaker interrupts a large current due to a short circuit accident in an electric circuit, an arc is generated, but the adjacent metal part may be melted and scattered around by the heat of the arc. As shown in the drawing, the contact spring 32 is biased in the direction in which the movable contact 9 is pressed against the fixed contact 11, and therefore the connecting portion 33 straddling the movable contact base 10 is exposed. When an arc is generated, the connecting portion 33 of the contact spring 32 is easily affected by the arc, and if the connecting portion 33 is melted, the function as the contact spring 32 cannot be achieved, the contact pressure is lost, and the contact contact is poor. Thus, after the short-circuit state is recovered, the circuit breaker cannot recover from the inability to energize. In addition to the contact spring 32, the molten metal may fly to the movable contact base 10 that holds the movable contact, and may be melted due to unsmooth operation of the movable contact base 10 or arc heat. In any case, the conventional circuit breaker has insufficient consideration for the components at the time of large current interruption, and if a large current interruption occurs like a short-circuit accident, it is difficult to ensure the energization performance after interruption, the stability of energization, Contact contact reliability is not maintained, and replacement is forced.

JP-A-5-74313 (paragraphs [0008] to [0022], FIG. 9) JP 2000-113798 A (paragraphs [0002] to [0005], [0022] to [0025], FIGS. 10 and 11)

  Therefore, by devising the structure and arrangement of the movable frame, movable control point base and contact spring, the heat of the arc generated when a short circuit accident occurs or the metal part scattered around by the heat is movable contact base. There is a problem to be solved in terms of preventing the influence on the contact spring.

  The object of the present invention is a circuit capable of ensuring the energization performance after the interruption and maintaining the stability of the energization and the reliability of the contact contact even when a large current interruption occurs as in a short circuit accident. Is to provide a circuit breaker.

  In order to solve the above problems, a circuit breaker according to the present invention comprises a fixed contact base carrying a fixed contact, a movable contact base carrying a movable contact, and the movable contact base rotated around a spindle. A movable frame that is movably supported, and a contact spring that is stretched between the movable contact base and the movable frame and applies contact pressure between the two contact points, are provided on both sides of the movable contact base. Two movable springs, two free arms extending from each spring body, an engaging part engaged with the movable frame, and the other arm extending from the spring body are connected to each other to make a movable contact. In the circuit breaker including the connecting portion that engages with the base, the spring main body portion and the connecting portion of the contact spring are arranged behind the movable frame from the viewpoint of both contacts.

  According to this circuit breaker, the circuit breaker ON / OFF operation itself is basically the same as that of the conventional circuit breaker, but the contact spring has its spring body portion and connecting portion from both contacts. Because it is placed behind the movable frame from the viewpoint of, if a large overcurrent flows in a short time due to a short circuit accident and an arc occurs between both contacts, the influence on the contact spring is as much as possible Can be reduced. That is, when both contacts are separated, an arc is generated between the two contacts. However, even if the influence of the metal part scattered around by the heat of the arc or the heat is exerted on the movable frame, the influence is blocked by the movable frame itself, and at least the spring main body part and the connection part of the contact spring. It does not reach. Therefore, the spring function of the contact spring is protected, and as a result, the energization performance in the circuit breaker when the short-circuit accident is recovered can be ensured.

  By making the structure of the contact spring and the movable frame in this way, the movable frame has a shape covering most parts including the spring main body portion and the connecting portion of the contact spring from the viewpoint from both contact sides. There is a possibility that only the engaging portion that is composed of two free arms and engages the movable frame is exposed. Even if the engagement part may be affected by the arc and partly melts, the engagement with the movable frame is likely to remain, and as long as such engagement remains, contact between both contacts The function of applying pressure is maintained.

  In this circuit breaker, it is preferable that the spring main body portion and the connecting portion of the contact spring are engaged with the rear side of the movable contact base from the viewpoint of both contacts. Since the spring body and connecting part of the contact spring are located behind the movable contact point from the viewpoint of both contacts, if an arc occurs between the two contacts due to a short circuit accident, the heat of the arc Even if the influence of the metal part scattered around by the heat reaches the place where the contact spring of the movable contact base is provided, the influence is blocked by the movable contact base itself and reaches the connection part of the contact spring. It does not reach.

  In the circuit breaker described above, the engaging portion and the connecting portion of the contact spring can be arranged in a manner extending from the support shaft in a direction substantially perpendicular to a line connecting the movable contact and the support shaft. With regard to the contact spring, by disposing the engaging portion that engages with the movable frame and the connecting portion that engages with the movable contact base in this manner, the engaging portion and the connecting portion are substantially the same distance from the viewpoint from the contact point. When an arc is generated, the engagement part exposed to both contact points should be removed when considering the distantly distant arrangement from the influence of the arc or the rotation of the movable contact point when the two contacts are separated. An arrangement away from the connecting portion can be obtained. When the torsion spring portion of the contact spring is locked to the support shaft of the movable contact base, the contact spring is stably locked to the movable frame.

The circuit breaker described above is disposed between the operation unit for manually turning on and off and the movable frame, and includes an opening / closing mechanism that acts on the movable frame and performs an opening / closing operation between both contacts. The opening / closing mechanism has a two-link and a drive spring, and a position between a contact position where the movable frame is urged to contact both contacts provided on each side of the unstable point and a position where the both contacts are separated and urged. The toggle mechanism can be configured to be switched with. As described above, the opening / closing mechanism is arranged between the manual operation unit and the movable frame, and is configured as a toggle mechanism using a drive spring, whereby the operation unit is operated to manually turn on and off. Sometimes, the toggle mechanism consisting of a two-bar link and a drive spring moves beyond the instability point determined by the state that the two-bar link extends in a straight line, and exceeds the instability point based on the spring force of the drive spring. The movable frame can be urged to the side, and the position can be changed by switching to a contact position where both the contacts are urged to contact or an opening position where both the contacts are separated and urged.

  According to the circuit breaker of the present invention configured as described above, the contact spring is characterized in that its connecting portion is arranged behind the movable frame from the viewpoint of both contacts, so that a short circuit accident or the like When a large current interruption occurs as described above and a large overcurrent flows in a short time and an arc is generated between the two contacts, the influence of the arc heat or the metal part scattered around by the heat is affected. Even when it reaches the movable frame, the influence is blocked by the movable frame itself and does not reach the torsion spring portion or the connecting portion of the contact spring. Therefore, the influence of the arc on the contact spring can be reduced as much as possible, and the spring function of the contact spring is preserved. As a result, the energization performance after breaking is ensured and a highly reliable circuit breaker is realized. can do.

  Based on FIGS. 1-4, the detail of embodiment of the circuit breaker by this invention is demonstrated. 1 is a top view of an internal structure including a movable part of a circuit breaker, FIG. 2 is a sectional view of the circuit breaker related to FIG. 1, and FIG. 3 is a sectional view of the movable frame in the circuit breaker shown in FIG. FIG. 4 is an enlarged plan view showing the main part of the movable frame in the circuit breaker structure shown in FIG. In each figure, the same components and parts used in the conventional circuit breaker shown in FIG. 5 or FIG.

  Although the circuit breaker shown in FIGS. 1-3 is abbreviate | omitting illustration, the thing equivalent to the toggle mechanism shown in FIG. 7 is provided. The movable frame 7 includes sleeve portions 40, 40 extending along the movable contact base 10 on each side of the movable contact base 10, and a bridge portion 41 that connects both the sleeve portions 40, 40. The movable contact base 10 extends toward the fixed contact base 12 when the movable contact 9 and the fixed contact 11 are in contact with each other, and can be rotated around the support shaft 10a in the open state. It is surrounded by the parts 40 and 40 and the bridge part 41. Therefore, the movable frame 7 is configured to surround the side away from the movable contact 9, that is, the periphery of the support shaft 10a.

  A contact spring 42 constituted by a torsion spring is formed on each side of the movable frame 7 from a spring main body 43 constituted as a torsion spring, and a distal end portion of one free arm 43 a extending from the spring main body 43. An engaging portion 44 that engages with the movable frame 7 and a connecting portion 45 that connects the distal ends of the other arm 43b extending from the spring main body portion 43 to engage with the movable contact base 10 are provided. .

  The spring main body 43 is wound several times in a coil shape and is used by being displaced in the twisting direction, and is loosely locked around the support shaft 10 a of the movable contact base 10. From the spring main body 43, arms 43a and 43b extend in the direction of the handle 3 that is substantially upward in FIG. 2 (FIG. 3) and the direction of the case 1 that is approximately 180 degrees opposite thereto. The direction in which the arms 43a and 43b extend is a direction substantially orthogonal to a line connecting the contact point where the contacts 9 and 11 are in contact with the support shaft 10a. The locking portion 44 is engaged with the movable frame 7 by contacting an end edge 41 a that defines the edge of the opening 40 a of the bridge portion 41. The connecting portion 45 is engaged with the movable contact base 10 at the bottom portion of the U-shaped groove 46 formed on the back side thereof. In FIG. 2, the movable frame 7 is shown by cutting a position away from the position of the opening 40a by a vertical plane extending in the front-rear direction, and in FIG. 3, passing through the opening 40a in the front-rear direction. It is shown cut by a vertical plane extending to

  In the contact spring 42, the engaging portion 44 and the connecting portion 45 are engaged with the movable frame 7 and the movable contact base 10, respectively, in a state where the spring main body portion 43 is twisted and deformed. Therefore, the movable contact base 10 is urged counterclockwise in FIGS. 2 and 3 around the support shaft 10a by the restoring force of the torsion spring force acting between the engaging portion 44 and the connecting portion 45. The movable contact 9 comes into contact with the fixed contact 11 and can be energized. Although the movable frame 7 receives the same reaction force due to the restoring force of the spring force, the movable frame 7 does not operate because it is not a force large enough to move the movable frame 7.

  In the circuit breaker having the above-described structure, when the contact spring 42 is viewed from the contact portion side of the movable contact 9 and the fixed contact 11, it is the distal end portion of the arms 43b and 43b of the contact spring 42 and the movable frame 7 Only the engaging portion 44 that engages with is exposed. Further, as can be seen from the extending direction of the arms 43a and 43b, the engaging portion 44 and the connecting portion 45 extend in a direction substantially perpendicular to a line connecting the movable contact 9 and the support shaft 10a from the support shaft 10a. Has been placed. Therefore, most of the contact spring 42, that is, the spring main body portions 43, 43 and the connecting portion 45 occupy the position on the back side covered with the movable frame 7. As shown in FIG. 4, which is an enlarged plan view of the main part of the movable frame 7, the opening 40 a surrounded by the sleeve portion 40 and the bridge portion 41 occupies a very small ratio in the movable frame 7 even when viewed from above. There is a narrow area (in FIG. 4, the peripheral edge is hatched), and the engaging portion 44 of the contact spring 42 is only slightly exposed to the opening 40a. Since most of the main part of the contact spring 42 is not exposed, even when the breaker interrupts a large current due to the occurrence of a short circuit accident in the electric circuit and the metal melt due to the arc is scattered, It is possible to prevent damage to parts, fusing, and the like. In this way, it is possible to maintain energization performance even after the short-circuit current is interrupted, and a highly reliable circuit breaker can be realized.

  Another embodiment of the present invention will be described with reference to FIGS. In the above-described embodiment, it is necessary to pass the spring arm 43-a through the opening 40-a of the movable frame 40, and the assembly workability is not considered much.

  In this embodiment, the workability is dramatically improved by a structure in which the arm 43-a of the spring is hung on the engaging portion 40-b of the cantilever support structure of the movable frame provided in the movable frame 40 and assembled.

  The movable contact base 10 receives a force in the contact side direction by the contact spring 42 by the arrangement of the contact spring 42 of the present invention. Therefore, since it is pressed against the bottom of the U-shaped groove 46 formed in the movable frame 7, the movable contact base 10 can be assembled to the movable frame 7 without adding any special parts.

  As is apparent from the above inventions, the arrangement of the contact springs and the shape in which the contact springs are hardly exposed are formed on the movable frame, so that the energization performance can be maintained even after the short-circuit current is interrupted. A highly reliable circuit breaker can be provided.

The top view which shows one Embodiment of the circuit breaker (for 1 pole) by this invention. Sectional drawing of another embodiment of the circuit breaker by this invention. FIG. 3 is another cross-sectional view of the circuit breaker shown in FIG. 2. The enlarged plan view which shows the principal part of the movable frame in the circuit interruption structure shown in FIG. The longitudinal cross-sectional view of the conventional circuit breaker. The top view of the circuit breaker shown in FIG. The side schematic diagram which shows the principal part of the conventional circuit breaker. Sectional drawing of the circuit breaker of other Examples of this invention Top view of the circuit breaker of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Case 2 ... Cover 2a ... Opening part 3 ... Handle 4 ... Opening / closing mechanism 5 ... Handle lever 6 ... Shaft 7 ... Movable frame 7a ... Center of rotation 9 ... Movable contact 10 ... Movable contact base 10a ... Support of movable contact base Shaft 11 ... Fixed contact 12 ... Fixed contact base 13 ... Upper lever 14 ... Lower lever 15 ... Pivoting shaft 16, 17 ... Pin 21 ... Bimetal 22, 23 ... Electromagnet 24 ... Latch 25 ... Arc extinguishing device 31 ... Drive spring 32 ... Contact spring 33 ... connecting portion 40 ... sleeve portion 40a ... opening 41 ... bridge portion 41a ... edge 42 ... contact spring 43 ... spring body 43a, 43b ... arm 44 ... engaging portion 45 ... connecting portion 46 ... U-shaped groove

Claims (4)

A fixed contact base carrying a fixed contact,
A movable contact stand carrying a movable contact,
A movable frame that rotatably supports the movable contact base around a support shaft;
A contact spring that is applied between the movable contact base and the movable frame and applies a force to contact the two contacts;
The movable frame is configured to surround the support shaft.
The contact spring is locked around the spindle;
The contact spring is located behind the movable frame and is surrounded by the movable frame around the support shaft, and is disposed at a position covered by the movable frame from the viewpoint of the two contacts .
When a large current interruption occurs and a large overcurrent flows in a short period of time, and when both contacts are separated, an arc occurs between both contacts.
Even if the heat of the arc or the influence of the metal part scattered around by the heat reaches the movable frame, the influence is blocked by the movable frame itself, and the influence of the arc on the contact spring is reduced. circuit breaker according to claim <br/> that can. The contact spring is
Two spring body portions respectively disposed on both sides of the movable contact base;
An engaging portion which is composed of one free arm extending from each spring body portion and is engaged with the movable frame;
And a connecting portion that connects the other arms extending from the spring main body and engages the movable contact base,
2. The circuit breaker according to claim 1, wherein the connection portion of the contact spring is engaged at a position covered by the movable contact base from a viewpoint from both the contacts. The engagement portion and the connection portion of the contact spring are arranged in a manner extending from the support shaft in a direction substantially perpendicular to a line connecting the movable contact and the support shaft,
The circuit breaker according to claim 1 or 2, wherein the engaging portion of the contact spring is configured to engage with a locking portion of a cantilever support structure of the movable frame. An open / close mechanism that is disposed between an operation unit that is manually turned on / off and the movable frame and that operates on the movable frame and performs an open / close operation between the two contacts;
The opening / closing mechanism has a two-node link and a drive spring, and the movable frame is provided on each side of the unstable point. The circuit breaker according to any one of claims 1 to 3, wherein the circuit breaker is configured as a toggle mechanism that switches between positions.

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