JP2005093151A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve breaking performance by preventing a movable contactor from bouncing back from a pole-opening position with the use of a spring member built into a contactor holder as a pressure contact spring for the movable contactor. <P>SOLUTION: The circuit breaker has a rotation system bridging type movable contactor 4 loosely retained by a contactor holder, and drives the movable contactor toward the pole-opening position with electromagnetic repulsive force acting between fixed contactors 2, 3 and the movable contactor when an overcurrent flows. Two sets of double-torsion springs 7 functioning as the pressure-contacting springs of the movable contactors are arranged at the contactor holder at axial symmetry around a rotation center of the movable contactor, and contact points of the movable contactor are pressed and biased toward a fixed contact point with a spring load of the spring member at a pole-closing position. A load working point of the double-torsion springs against the movable contactor is set at a position to bias the movable contactor toward a pole-closing direction in the vicinity of a pole-closing position, and to bias the movable contactor toward a pole-opening direction in the vicinity of the pole-opening position with a direction of a line of action of the spring load reversed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a circuit breaker intended for an auto breaker and the like, and more particularly to a structure of a current breaker.

  As the circuit breaker mentioned above, a bridge-type movable contact held by a rotating contact holder is adopted for the current interrupting part, and the electromagnetic acting between the fixed contact and the movable contact when overcurrent is applied. 2. Description of the Related Art A two-contact circuit breaker that opens a movable contact using a repulsive force as a driving force is known (for example, see Patent Document 1).

  In addition, for the current interrupting part of the circuit breaker, a contact pressure spring of the movable contact arranged in the contact holder in combination with the movable contact (a predetermined contact pressure is applied between the movable contact and the fixed contact at the closed position). As a spring to be applied, a structure using a torsion coil spring of a double torsion type has been proposed in Japanese Patent Application No. 2001-158049 by the same applicant as the present invention. Next, the structure of the current interrupting portion is described. It shows to Fig.5 (a)-(c).

  5 (a) to 5 (c), 1 is a case of a current interrupting portion, 2 and 3 are fixed contacts on the power source side and the load side, which are arranged in the diagonal of the case 1 and 4 are fixed contacts. Rotating movable contacts 4 and 4a that bridge between the contacts 2 and 3 are movable contacts 4a that are provided at both ends of the movable contact 4 so as to face the contacts of the fixed contacts 2 and 3, and 5 is the movable contact 4 Is a rotary drum-type contact holder that is mounted in combination with a contact pressure spring as described later, 6 is an arc extinguishing device (grid), and the movable contact 4 is a space 5 a formed in the body of the contact holder 5. Of the movable contact 4 as a contact pressure spring of the movable contact 4 and sandwiching the movable contact between the upper and lower sides (axisymmetric positions with respect to the rotation center O of the movable contact 4). A double torsion type torsion coil spring (hereinafter referred to as “double torsion spring”) 7 is interposed. And so as to bias the movable contact 4 at the rotation center O of the turn in the closing direction (counterclockwise direction) by the spring force of the double torsion spring 7 (couple). The current interrupting sections for each phase are combined in a horizontal row, and the contact holders 5 for each phase are linked to an opening / closing mechanism (not shown) so that the opening / closing operations are collectively performed by a handle operation.

  The fixed contacts 2 and 3 are folded back in a U shape at the tip side, and when a large overcurrent (short-circuit current) flows through the main circuit, the fixed contacts 2 and 3 and the movable contact 4 The movable contact 4 is driven in the opening direction by utilizing the electromagnetic repulsive force acting on the magnetic poles to cut off the current limit, and a magnetic yoke 8 is disposed at the U-shaped folded portions of the fixed contacts 2 and 3. Thus, the magnetic driving force applied to the arc extinguishing device 6 is increased by strengthening the magnetic field acting on the arc generated between the contacts of the fixed / movable contactor when the current is interrupted.

  Here, the support structure of the movable contact 4 mounted on the contact holder 5 will be described in detail. The double torsion springs 7 arranged on the upper and lower sides of the movable contact 4 as contact pressure springs are as shown in FIG. L-shaped leg portions 7a are formed at both ends of the coil, and an offset arm portion 7b that is bent in a U-shape and protrudes to the side is formed at the center portion of the coil. It is constructed so as to straddle the back surface (the surface opposite to the movable contact 4a) and is interposed between the contact holder 5 in a bent state, and at this position, the tip of the offset arm portion 7b is attached to the movable contact 4 It is pressed against the back and pressed in the closing direction. The double torsion spring 7 disposed on the upper side of the movable contact 4 has its offset arm portion 7b abutting on the upper surface of the movable contact 4, and the double torsion spring disposed on the lower side has an offset arm portion of the movable contact 4. A spring force (spring load) is applied to the movable contact 4 in contact with the lower surface side.

  With this configuration, at the closed position shown in FIG. 6 (a), the spring loads f1, f2 applied to the movable contact 4 from the double torsion spring 7 act as couples, and the contact 4a of the movable contact 4 is used as a fixed contact. Contact pressure is applied by applying pressure to a few contacts.

  When an overcurrent (short-circuit current) flows in the main circuit due to this closing and energization, the movable contact 4 is opened by receiving an electromagnetic repulsive force acting between the fixed contacts 2 and 3 and the movable contact 4. Then, against the spring force of the double torsion spring 7, it moves to the open position shown by the chain line in FIG. 5 (b), stretches the arc generated between the fixed / movable contacts, and then opens and closes the opening / closing mechanism. Then, the contact holder 5 is rotated clockwise to complete the blocking operation.

  By the way, when the overcurrent (short-circuit current) flows as described above, the circuit breaker that cuts the current limit by driving the movable contact to the open position by the electromagnetic repulsive force acting between the fixed contact and the movable contact In order to obtain a high breaking performance in the device, it is important that the speed of the movable contact at the time of opening operation is fast and that the arc generated between the fixed / movable contacts is kept extended. It is necessary to keep the movable contact opened by receiving the electromagnetic repulsion force in the open position until the arc disappears.

  On the other hand, in the above configuration, the spring loads f1 and f2 (represented by vectors) of the double torsion spring 7 as can be seen from the open and closed operation state diagrams shown in FIGS. 6 (a) and 6 (b). ) Acts in the direction of closing the movable contact 4 regardless of the opening and closing positions of the movable contact 4. Moreover, the electromagnetic repulsion force decreases as the distance between the fixed contact and the movable contact increases during the opening operation, whereas the spring load acting on the movable contact 4 is conversely the double torsion spring 7. The amount of bending increases as shown in the characteristic diagram of FIG. Therefore, in this state, the opening speed of the movable contact 4 is reduced and the breaking performance is deteriorated, and the movable contact 4 once moved to the fully opened position due to the electromagnetic repulsive force of the overcurrent rebounds, and the double torsion spring 7 There is a risk that the spring load f will be applied and the position will reverse to the closed position and the contact will be re-entered.

Therefore, conventionally, as a measure for preventing rebound during the opening operation, a structure provided with a latch mechanism for locking and holding the movable contact at the fully open position (see, for example, Patent Document 2), the movable contact and the contact holder, Are connected by a special link mechanism that is urged by a drive spring, and a load is applied through the link mechanism to press the contact of the movable contact to the fixed contact at the closed position, and reverse at the open position. A structure in which a load is applied to open the movable contact in the opening direction (see, for example, Patent Document 3), and a snap spring having a concave and convex surface formed on a leaf spring as a drive spring for the movable contact It spans between the movable contact and the case, and the snap spring biases the movable contact toward the closing side in the vicinity of the closing position, and the snap spring reverses in the vicinity of the opening position to open the moving contact. Urged to the extreme side Those formed (e.g., see Patent Document 4) it has been proposed.
JP-A-6-289964 Japanese Patent Laid-Open No. 11-312452 Japanese translation of PCT publication No. 2002-517064 Japanese Patent Laid-Open No. 2001-210216

  By the way, in the above-described conventional measures for preventing the movable contact from rebounding, the structure of the contact holder is complicated and the number of parts is increased, and the increase in the mass of the movable mechanism including the contact holder allows high-speed operation due to electromagnetic repulsion. There are problems such as blocking and lowering the blocking performance. Although the configuration of Patent Document 4 that uses a snap spring as the drive spring for the movable contact seems to be able to cope with a simple structure at first glance, the spring characteristics are actually used for the opening and closing operations of the movable contact. It is difficult to reverse them together, and it takes a considerable amount of force to reverse the snap spring while the movable contact is moving to the closing / opening position. In addition, the opening speed of the movable contact may be reduced to reduce the breaking characteristics.

  The present invention has been made in view of the above points, and skillfully utilizes a spring member incorporated in a contact holder as a contact pressure spring of a movable contact, based on the configuration of the circuit breaker shown in FIG. Accordingly, it is an object of the present invention to provide an improved circuit breaker that can secure high breaking performance with a simple structure without requiring a change such as adding new parts.

In order to achieve the above object, according to the present invention, the rotary bridge movable contact is loosely fitted and held in the contact holder, and when an overcurrent flows, the fixed contact and the movable contact A circuit breaker that drives the movable contact toward the open position with an electromagnetic repulsive force acting between them, and the contact holder has two sets of spring members that function as contact pressure springs for the movable contact. In a configuration in which the contact of the movable contact is pressed and urged to the fixed contact by the spring load of the spring member at the closed position, arranged in an axially symmetrical position with respect to the rotation center of the child,
The load acting point of the spring member on the movable contact is biased in the closing direction in the vicinity of the closing position, and the direction of the acting line of the spring load is reversed in the vicinity of the opening position so that the moving contact is The position is set so as to be urged in the opening direction (Claim 1), and specifically, configured in the following manner.

  (1) The spring member is a torsion coil type double torsion spring, and both ends of the spring are engaged with the contact holder, and the center offset arm is engaged with the back of the movable contact. Is arranged at a position symmetrical to the axis of rotation.

  (2) A leaf spring is used as the spring member, and the leaf spring is bent and spanned between the contact holder and the back of the movable contact so as to be laid in an axially symmetric position with respect to the center of rotation. Item 3).

  (3) In the preceding paragraphs (1) and (2), in order to obtain a stable contact pressure by absorbing the imbalance of the contact pressure acting on the two contact points of the bridge-type movable contactor at the closed position, the movable contact An elongated hole is opened at the center of rotation of the child along the direction connecting the load application points of the two spring members, and the elongated member is supported by the contact holder through the support shaft. .

  (4) Further, in order to simplify the assembly structure of the current interrupting portion, a support shaft that penetrates the movable contact is also used as a support shaft of the contact holder (claim 5).

  (5) Aside from the movable contact and the support holder spindle in (5), a drive pin that penetrates the contact holder of each phase arranged in a horizontal row is provided, and the drive pin is linked to the opening / closing mechanism. The movable contacts of each phase can be collectively operated (claim 6).

In the present invention, two sets of spring members functioning as contact pressure springs of the movable contact are arranged on the contact holder in an axially symmetrical manner with respect to the rotation center of the movable contact, and the spring load of the spring member is at the closed position. In the circuit breaker that presses and urges the contact of the movable contact to the fixed contact,
The load acting point of the spring member on the movable contact is biased in the closing direction in the vicinity of the closing position, and the direction of the acting line of the spring load is reversed in the vicinity of the opening position so that the moving contact is It shall be set to a position that urges in the opening direction, and here a double torsion spring or a leaf spring is adopted as the spring member,
The movable contact opened by the electromagnetic repulsive force acting between the fixed contact and the movable contact when the short-circuit current is interrupted can be held at the open position, thereby extending the arc generated between the contacts. In the middle of the opening operation when the overcurrent is interrupted, the speed of the movable contactor can be further accelerated without decelerating, and high interrupting performance can be obtained. Moreover, it is possible to easily cope with this by simply using the spring member provided as the contact pressure spring of the movable contact and changing the load acting point with the movable contact without adding any parts.

  Moreover, according to the structure of Claim 4, it is possible to stably balance the contact pressure applied to the two contacts of the bridging contact by suppressing the influence of contact consumption due to the repetition of the current interruption operation. Further, by adopting the configurations of claims 5 and 6, the structure can be simplified.

  The present invention utilizes two sets of spring members equipped in the contact holder as contact pressure springs of the movable contact, and prevents the movable contact from rebounding during the opening operation, thereby improving the breaking performance. The load acting point on the movable contact of the spring member is biased in the closing direction in the vicinity of the closing position, and as a means for this, the direction of the acting line of the spring load is in the vicinity of the opening position. The position is set so as to reverse and urge the movable contact in the opening direction, and a specific mode thereof will be described based on the following embodiment. In the drawings of the respective embodiments, members corresponding to those in FIGS. 5 and 6 are denoted by the same reference numerals and description thereof is omitted.

  1 (a) to 1 (d) show an embodiment corresponding to claim 2 of the present invention. In this embodiment, the current interrupting portion is basically the same as the configuration of FIG. 5, but two sets of double torsion springs 7 mounted on the contact holder 5 as contact pressure springs of the movable contact 4 are as follows. Is arranged. That is, the double torsion springs 7 arranged above and below the movable contact 4 are displaced from side to side so as to be axially symmetric with respect to the support shaft 9 provided at the rotation center of the movable contact 4. The offset arm portion 7b protruding from the center of the double torsion spring 7 is made shorter than the configuration of FIG. 5, and the tip of the arm portion is fitted into the engagement recess 4b formed on the back surface of the movable contact 4 so that the movable contact is possible. I'm hanging on a child.

  With this configuration, at the closed position in FIG. 1 (a), the spring loads f1 and f2 of the double torsion spring 7 act on the movable contact 4 as a couple and press the movable contact 4a against the contacts of the fixed contacts 2 and 3. Thus, contact pressure is applied between the contacts. When a short-circuit current flows from this state to the main circuit and the movable contact 4 is opened by receiving the electromagnetic repulsive force, the movable contact 4 takes the state shown in FIG. Turn to the open position of (c). Here, as the opening distance between the fixed contact / movable contact increases, the direction of the line of action of the spring loads f1, f2 of the double torsion spring 7 changes as shown by the vector shown in FIG. 1 (b). In this state, the spring loads f1 and f2 cancel each other, and the spring load acting on the movable contact 4 becomes zero. If the opening distance further increases after passing through this point, as shown in FIG. 1 (c). The lines of action of the spring loads f1 and f2 are reversed in the direction opposite to that shown in FIG. 1 (a), and the movable contact 4 is biased in the opening direction in response to this spring load. A characteristic diagram showing the relationship between the spring load and the opening distance of the movable contact is as shown in FIG.

  As a result, the movable contact 4 that is opened by the electromagnetic repulsive force when the short-circuit current is interrupted does not receive a large deceleration force in the course of the opening process, and doubles when it passes through the intermediate point (state shown in FIG. 1 (b)). In response to the spring loads f1 and f2 of the torsion spring 7 and further accelerated, the movable contact 4 does not rebound from the fully open position even if the electromagnetic repulsion disappears due to current interruption when the fully open position is reached. As a result, high shutoff performance can be secured.

  Moreover, as is apparent from the illustrated structure, it can be handled without adding parts to the contact holder 5 as compared with the structure of FIG.

  Next, an embodiment corresponding to claims 3 and 4 of the present invention is shown in FIGS. In this embodiment, the double torsion spring 7 in the first embodiment is replaced with a plate spring 10 having a simple structure. As shown in the figure, the movable contactors are bent in the two sets of plate springs 10. 4 is installed between the upper and lower back surfaces and the contact holder 5, and in the closed position shown in FIG. 2 (a), the contact of the movable contact 4 is urged against the fixed contact by the spring loads f1 and f2 of the leaf spring 10. doing. A shaft hole through which the support shaft 9 passes is opened at the center of rotation of the movable contact 4, and this shaft hole extends along a line connecting the engagement points of the two sets of leaf springs 10 and the movable contact 4. It is formed as a long hole 4b.

  With this configuration, when the movable contact 4 is opened by an electromagnetic repulsive force due to a short circuit current of the main circuit, the spring load acting on the movable contact 4 as the distance between the electrodes increases as in the first embodiment. The direction of the lines of action of f1 and f2 changes, whereby the movable contact 4 is held at the fully open position in FIG. 2 (c) through the state of FIG. 2 (b). Further, the contact 4a of the movable contact 4 is consumed by repetition of the current interruption operation, and the contact consumption amount differs between the two contacts formed at both ends of the bridge-shaped movable contact 4, as shown in the figure. Since the center shaft hole of the movable contact 4 is loosely supported on the support shaft 9 as a long hole 4b, the spring loads of the two leaf springs 10 are movable contacted in the closed state regardless of variations in contact consumption. A stable contact pressure can be applied by acting in a balanced manner between the two movable / fixed contacts of the child 4.

  Moreover, by adopting the leaf spring 10 as the spring member, the structure of the parts is simpler than the double torsion spring 7 of the first embodiment, and the contact holder can be downsized.

  Next, an assembly structure of a current breaker according to the first and second embodiments and a three-phase circuit breaker constructed by combining the current breakers for three phases is shown in FIGS. 3 and 4 as third and fourth embodiments. Show.

  In FIG. 3, in this embodiment, for each current interrupting portion of each phase constituting the three-phase circuit breaker, the support shaft 9 penetrating the rotation center of the movable contact 4 in the previous embodiment is connected to the contact holder 5. The structure is also used as a spindle.

  That is, the support shaft 9 is passed through the center of rotation of the contact holder 5, and the shaft end is supported by a bearing portion (not shown) formed inside the case 1 (division structure) of the current interrupting portion, The movable contact 4 and the contact holder 5 are pivotally supported. In addition to the support shaft 9, a common drive pin 11 is provided for each phase passing through the contact holder 5 and the arc-shaped shaft hole 1 a opened in the side wall surface of the case 1. After passing through the current interrupting portions of the respective phases arranged, they are connected to an operation handle (rocker handle) 13 via an opening / closing mechanism 12 of a circuit breaker.

  When the operation handle 13 is tilted to the ON / OFF position in the above configuration, the drive pin 11 moves in the vertical direction via the opening / closing mechanism 12, and the contact holder 5 of the current interrupting portion of each phase is linked to the support shaft 9. To move the movable contact 4 to the open and closed positions.

  According to this assembly structure, the single support shaft 9 is shared so that the movable contact 4 and the contact holder 5 are pivotally supported, and another drive pin 11 is provided between the current interrupting portions of each phase. As a result, the movable contact 4 and the contact holder 5 can be pivotally supported and the current interrupting portion of each phase can be linked to the opening / closing mechanism 12 with a small number of parts and a simple structure.

  Next, an application example of the above-mentioned Example 3 is shown in FIG. That is, in the configuration of Example 3 (see FIG. 3), in the assembled state in which the current blocking portions for three phases are arranged side by side, the support shafts 9 provided for each phase are not aligned and aligned. There is a problem that when the current blocking portions for three phases are operated to be turned on and off in conjunction with each other via the drive pin 11, a turning operation or the like occurs and the smooth operation cannot be performed.

  Therefore, in this embodiment, in order to compensate for the variation in the assembly accuracy and to smoothly operate the current interrupting portions of the respective phases, the two drive pins 11 straddle the current interrupting portions of the respective phases. Is installed at a position offset from the rotation center of the contact holder 5, and the supporting shaft 9 provided at the current interrupting portion of each phase is supported by bearing in a fixed position in any one of the three phases, and the remaining two phases As for the support shaft 9, it is loosely supported on the bearing portion of the case 1 so that the support of the support shaft 9 has some backlash, and the drive force is cut off from the opening / closing mechanism 12 via the two drive pins 11. The contact holder 5 is driven to the ON / OFF position.

  As a result, even if there is some variation in assembly accuracy in a state where the current interrupting portions of the respective phases are coupled, the current interrupting portions of the respective phases can be smoothly operated in an interlocked manner without causing problems such as turning.

FIG. 5 is an operation explanatory diagram of the current interrupting unit corresponding to the first embodiment of the present invention, where (a), (b), and (c) are diagrams showing the operating states of the closing, opening, and opening positions, respectively. ) Is a characteristic diagram showing the relationship between distance between poles and spring load FIG. 6 is an operation explanatory diagram of a current interrupting unit corresponding to Example 2 of the present invention, and (a), (b), and (c) are diagrams showing the operating states of the closing, opening, and opening positions, respectively. The disassembled perspective view showing the assembly structure of the three-phase circuit breaker corresponding to Example 3 of this invention The disassembled perspective view showing the assembly structure of the three-phase circuit breaker corresponding to Example 4 of this invention BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the conventional electric current interruption part of the circuit breaker used as the implementation object of this invention, (a), (b) is a top view showing an internal structure, respectively, (c) is a movable contactor and a contactor Perspective view showing assembly structure with holder FIG. 5 is an operation explanatory diagram of FIG. 5, (a) and (b) are diagrams showing the operating state of the closed and open positions, respectively, and (c) is a characteristic diagram showing the relationship between the distance between the poles and the spring load.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Case of current interruption part 2,3 Fixed contact 4 Movable contact 4a Movable contact 4b Elongated hole 5 Contact holder 7 Double torsion spring (spring member)
7b Offset arm part 9 Support shaft 10 Leaf spring (spring member)
11 Drive pin 12 Opening / closing mechanism 13 Operation handle

Claims (6)

The rotary bridge movable contact is loosely fitted and held in the contact holder, and when the overcurrent flows, the movable contact is opened by the electromagnetic repulsive force that acts between the fixed contact and the movable contact. A circuit breaker that is driven toward the two contacts, wherein the contact holder is provided with two sets of spring members that function as contact pressure springs of the movable contact in an axially symmetrical manner with respect to the rotational center of the movable contact In the closed position, the contact of the movable contact is pressed against the fixed contact with the spring load of the spring member.
The spring load acting point on the movable contact of the spring member is biased in the closing direction in the vicinity of the closing position, and the direction of the acting line of the spring load is reversed in the vicinity of the opening position so that the moving contact is reversed. The circuit breaker is characterized in that it is set at a position where it is energized in the opening direction. 2. The circuit breaker according to claim 1, wherein the spring member is a torsion coil type double torsion spring, and both ends of the spring are engaged with the contact holder, and the center offset arm is engaged with the back surface of the movable contact. The circuit breaker is characterized in that the circuit breaker is arranged at an axially symmetric position with respect to the center of rotation. 2. The circuit breaker according to claim 1, wherein the spring member is a leaf spring, and in a state in which the spring is bent, the spring member straddles between the contact holder and the back surface of the movable contact and is axially symmetric with respect to the center of rotation. A circuit breaker that is installed at a position. The circuit breaker according to claim 2 or 3, wherein an elongated hole is opened at a rotation center of the movable contactor along a direction connecting the load action points of the two sets of spring members, and the elongated hole is contacted through a support shaft. A circuit breaker characterized in that the child holder is pivotally supported. The circuit breaker according to any one of claims 1 to 4, wherein a support shaft penetrating the movable contact serves also as a support shaft of the contact holder. 6. The circuit breaker according to claim 5, further comprising a drive pin that is connected to an opening / closing mechanism through a contact holder of each phase arranged in a horizontal row separately from the movable contact and the support shaft of the contact holder. A circuit breaker characterized by that.

Images