JP2009238541A - Contact arrangement - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact arrangement capable of preventing sticking due to burning of a crossbar shaft owing to arcs generated when the contacts are forcibly opened. <P>SOLUTION: The contact arrangement includes a crossbar 30 and a switching mechanism 4. The crossbar 30 supports respective moving terminals 3 and works the moving terminals 3 in conjunction with each other. The switching mechanism 4 includes a plurality of link members 41 for transmitting rotation of a handle 40 to the crossbar 30 to make respective moving contacts 3a touch and detach from respective fixed contacts 2a. The crossbar 30 can freely rotate with its shaft 30a as an axis between a position at which the moving contact 3a touches the fixed contact 2a and a position at which the moving contact 3a detaches from the fixed contact 2a. A terminal assembly 2 has an extension piece 22 which is opposite to each contact and approximately parallel to the contact open/close direction. The extension piece 22 has a gas relief hole 22a at a position opposite to the operation range of the moving contact 3a to release arc gas which is generated when contacts are opened forcibly. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a contact device used for a circuit breaker or a switch.

  Conventionally, a contact device having means for preventing thermal energy from increasing between contacts due to an arc generated when an overcurrent such as a short-circuit current or an overload current flows and forcibly opens is known. Some are disclosed in Document 1. The contact device described in Patent Document 1 includes a plurality of power supply side terminal portions and load side terminal portions respectively disposed on both sides of the container body, contact portions disposed on the power supply side terminal section side, and the interior of the container body. An open / close mechanism that opens and closes the contact device in conjunction with the operation of an externally operated operating handle, and is opened and closed when an overcurrent such as a short-circuit current or overload current flows through the contact portion. And an overcurrent interruption mechanism that releases the mechanism and forcibly opens the contact portion. In addition, this contact device is equipped with a contact portion, a power supply side terminal portion, a load side terminal portion, and an overcurrent cutoff mechanism at each pole, and each overcurrent cutoff mechanism has a switching mechanism including an operation handle in common with each pole. And it becomes the structure linked with a contact part.

  The contact portion is fixed to a fixed contact fixed to a terminal plate extending from the power supply side terminal portion, and a movable contact that is rotatable between a position in contact with the fixed contact and a position away from the fixed contact. It consists of a movable contact that is placed opposite. The movable contact of each pole is housed in the body so as to straddle each pole, and is rotatably held by each pole-linked crossbar that rotates around the shaft portion according to the operation of the operation handle. ing.

In the vicinity of the movable contact in the movable contact, there is a fixed contact so that the distance between the fixed contact and the movable contact is smaller than the separation distance between the fixed contact and the movable contact with the opening operation of the movable contact. Electrode pieces made of a conductive material always facing each other with a gap are provided. Thus, the arc current generated at the time of forced opening spreads not only to the movable contact but also to the electrode piece, so that an increase in arc voltage can be suppressed, and the current is reduced to a substantially zero point while suppressing an increase in thermal energy. It can be blocked at the position.
Japanese Patent No. 2734615

  However, in the above conventional example, an electromagnetic force directed to the shaft portion side of the crossbar is generated by the current flowing between the contacts during forced opening, and the arc jumps to the shaft portion side of the crossbar and burns the shaft portion. There was a problem that the crossbar could not be rotated.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a contact device capable of preventing the shaft portion of the crossbar from being burned by an arc generated during forced opening.

  In order to achieve the above object, the invention according to claim 1 is a pair of terminal portions corresponding to input / output, a terminal plate having a fixed contact and connected to one terminal portion, and a movable contacting and separating from the fixed contact. A contact spring that has a contact and a movable contact that is connected to the other terminal portion is housed in a container for each of one or more poles, and applies a contact pressure when each movable contact contacts each fixed contact A crossbar that supports each movable contact while holding it between each movable contact and operates each movable contact in conjunction with the handle, and a handle that is rotatable between an on position and an off position. An opening / closing mechanism composed of a plurality of link members that contact and separate each movable contact with each fixed contact by transmitting the turning operation of the handle to the crossbar, and a force accumulated in a direction that breaks the balance of the opening / closing mechanism. Latch member that holds the balance of the open / close mechanism and fixed When an overcurrent flows between the point and the movable contact, the contact device includes an overcurrent interruption mechanism that drives the latch member to break the balance of the switching mechanism and forcibly opens the movable contact from the fixed contact, The crossbar is rotatable between the position where the movable contact comes into contact with the fixed contact and the position where the movable contact contacts the fixed contact, with the shaft provided on the shaft as an axis, and the terminal plate is substantially parallel to the contact and separation direction of the contact. And it has an extension piece facing each contact, and the extension piece is provided with an escape hole for releasing the arc gas generated at the time of forced opening at a position facing the operation range of the movable contact. To do.

  According to the present invention, the gas pressure is reduced by escaping the arc gas generated when the arc is generated, and the electromagnetic force in the direction toward the shaft portion of the crossbar between the contacts is compared with the case where no escape hole is provided in the terminal plate. Since the force can be weakened, it becomes difficult for the arc to fly to the crossbar shaft side, and therefore, the crossbar shaft portion can be prevented from being burned by the arc generated during forced opening.

  Hereinafter, embodiments of a contact device according to the present invention will be described with reference to the drawings. In the following description, the top, bottom, left, and right in FIG. In this embodiment, the three poles are opened and closed by a single opening / closing mechanism. As shown in FIGS. 1A to 1C, the terminal blocks 13 are respectively provided at the left and right ends of the substantially rectangular parallelepiped body 1. The left terminal block 13 is provided with three (one in the figure) power supply side terminal portions A along the width direction of the container 1, and the right terminal block 13 has a load side terminal portion B. Are arranged in parallel along the width direction of the vessel 1 (one in the figure). Each terminal block 13 is formed with an insulating wall 13a that insulates between adjacent power supply side terminal portions A and between load side terminal portions B. In each pole, a terminal plate 2 having a fixed contact 2a between the power supply side terminal portion A and the load side terminal portion B and connected to the power supply side terminal portion A, and a movable contact 3a contacting and separating from the fixed contact 2a. And the movable contact 3 connected to the load side terminal portion B is housed. The container 1 also includes an opening / closing mechanism 4 that opens and closes the contacts of each pole and an overcurrent blocking mechanism 5 that forcibly opens the contacts when an overcurrent flowing between the contacts is detected when the contacts are closed. Has been.

  The container body 1 is covered with a flat base 10 made of a synthetic resin molded product, a substantially rectangular parallelepiped body 11 made of a synthetic resin molded product disposed above the base 10, and an upper surface of the body 11. A box-shaped cover 12 made of a synthetic resin molded product having an open bottom surface is coupled to each other. An insulating wall 11a (see FIG. 1C) that divides the internal space into each pole is formed inside the body 12, and insulation between adjacent poles is achieved. Further, a substantially rectangular window hole 12a is provided in the upper surface of the cover 12 so as to expose an operation portion of the handle 40 described later. 2 (a) and 2 (b), two substantially rectangular air holes 11b are provided above the cross bar 30 (described later) of the body 12 and above the armature 53 (described later). An introduction hole 11c is provided. The vent hole 11b and the introduction hole 11c form a vent path for guiding the arc gas generated when the arc is generated to the armature 53.

  As shown in FIGS. 1A and 1B, the terminal plate 2 is made of a conductive material such as copper, for example, and has a screw hole 20a into which the terminal screw 14 of the power supply side terminal portion A is screwed. The terminal piece 20, the contact piece 21 to which the fixed contact 2 a made of a conductive material having higher arc resistance than copper such as silver, for example, is fixed, and the extended piece 22 that couples the terminal piece 20 and the contact piece 21. It is comprised by the substantially Z shape. The extension piece 22 has an insulating valve plate 23 made of an insulating material having elasticity, and a plurality of (four in the figure) substantially rectangular exhaust holes 24 a that are closed by the valve plate 23. An exhaust plate 24 made of a material is attached. Further, the extension piece 22 is provided with a substantially rectangular escape hole 22a through which arc gas generated by the generation of the arc is released at a position facing the operating range of the movable contact 3a.

  The valve plate 23 is bent outward due to the gas pressure of the arc gas generated when the arc is generated, and discharges the arc gas to the outside through the exhaust holes 24 a of the exhaust plate 24. Since the valve plate 23 closes the exhaust hole 24a except when an arc is generated, the valve plate 23 functions to prevent foreign matters such as dust from entering the inside of the vessel 1.

  The exhaust plate 24 is disposed so as to overlap the thickness direction of the exhaust plate 24. The arc extinguishing gas generating plate 24b generates arc extinguishing gas by the heat of the arc generated when the contact is opened, and the arc extinguishing gas generating plate 24b. A plurality (three in the figure) of grids 24c held by the exhaust plate 24 are provided. For this reason, the arc gas generated with the generation of the arc is discharged out of the body through the exhaust hole 24a of the exhaust plate 24, and the arc is divided and cooled by the grid 24c, and the arc extinguishing generated from the arc extinguishing gas generating plate 24b. The arc is extinguished by sex gas. Further, the contact piece 21 is provided with a contact protection plate 25 which is disposed so as to surround the fixed contact 2a to protect the fixed contact 2a and prevent the arc from re-igniting.

  As shown in FIG. 3A, the movable contact 3 is formed in a long flat plate shape from a conductive material such as copper, for example, and has an arc resistance higher than that of copper such as silver at one end portion in the longitudinal direction. A movable contact 3a made of a highly conductive material is fixed so as to face the fixed contact 2a. Further, in the vicinity of the movable contact 3a, an electrode piece 3b made of a conductive material having a melting temperature higher than that of the movable contact 3, such as iron, is provided. The electrode piece 3b is arranged so that the distance between the fixed contact 2a and the electrode piece 3b is smaller than the distance between the contacts during the opening operation of the contacts, and an arc generated at the time of opening is generated. An increase in arc voltage is suppressed so as to spread toward the electrode piece 3b, and an increase in thermal energy is suppressed. Connected to the other end in the longitudinal direction of the movable contact 3 is a connection line 31 composed of a braided wire that is electrically connected to the load side terminal portion B and a coil 51 described later. Thus, at the time of closing, the power supply side terminal portion A and the load side terminal portion B are electrically connected via the terminal plate 2, the movable contact 3 and the connection line 31.

  A rotary shaft 33 is provided at substantially the center of the movable contact 3, and the rotary shaft 33 is rotatably held by being held inside a cross bar 30 provided continuously across the poles. As shown in FIG. 1 (b), the cross bar 30 connects a plurality of (three in the drawing) holding portions 30b, which hold the movable contacts 3 of each pole at a predetermined interval, to each other by a shaft portion 30a. In each holding portion 30b, a contact pressure spring 32 (see FIG. 3A) formed of a coil spring is held in a compressed state between the inner surface of the holding portion 30b and the other end portion of the movable contact 3. Yes.

  As shown in FIG. 3A, the urging direction of the contact pressure spring 32 includes a point a where the holding portion 30b and the contact pressure spring 32 are in contact, and a point b where the movable contact 3 and the contact pressure spring 32 are in contact. And the point c of the rotary shaft 33. That is, when the normal contact is opened and closed, the movable contact 3 is biased counterclockwise because the point b is positioned above the straight line connecting the point a and the point c. Due to the electromagnetic repulsive force between the contacts, the movable contact 3 rotates clockwise against the urging force of the contact pressure spring 32, and the point b is located below the straight line connecting the points a and c. Therefore, the movable contact 3 is urged clockwise.

  The opening / closing mechanism 4 is connected to the handle 40, which is rotatably held by the body 12 and has an operation portion protruding outside through the window hole 12 a of the cover 12, and the handle 40 and the crossbar 30. And a plurality of link members 41 for interlocking the crossbar 30 in accordance with the rotational movement. The handle 40 is rotatable between an ON position (see FIGS. 3A and 3B) for closing the contact and an OFF position (see FIGS. 3C and 3D) for opening the contact. When the handle 40 is turned to the on position, the cross bar 30 is turned counterclockwise, and when the handle 40 is turned to the off position, the cross bar 30 is turned clockwise. . Thus, in conjunction with the closing operation of the handle 40, the opening / closing mechanism 4 rotates the cross bar 30 counterclockwise about the shaft portion 30a, so that the movable contact 3a comes into contact with the fixed contact 2a, and the contact pressure A contact pressure is applied between the contacts by the biasing force of the spring 32. Further, in conjunction with the opening operation of the handle 40, the opening / closing mechanism 4 rotates the cross bar 30 clockwise about the shaft portion 30a, whereby the movable contact 3a is separated from the fixed contact 2a. In addition, since the structure of such an opening-and-closing mechanism 4 is known, detailed description shall be abbreviate | omitted here.

  As shown in FIG. 3A, the overcurrent interrupting mechanism 5 includes a fixed core 50 disposed on the terminal plate 6 of the load side terminal portion B so that the longitudinal direction is along the vertical direction, and the fixed core 50. One end is provided at the upper end of the yoke 52 so as to face the upper end of the fixed coil 50, the coil 52 wound around the coil 51, the yoke 52 attached to the side of the fixed core 50. An armature 53 that is supported and urged clockwise by a return spring 54 that is a coil spring, and a latch member 55 that is positioned on the locus of rotation of the armature 53 and that interlocks with the link member 41 of the opening / closing mechanism 4. Composed.

  The armature 53 is located away from the upper end portion of the fixed core 50 by the urging force of the return spring 54 except when an overcurrent is generated. However, when an overcurrent is generated, the fixed core 50 is caused by an overcurrent flowing through the coil 51. Is excited and attracts the armature 53, so that the armature 53 rotates counterclockwise against the urging force of the return spring 54 and comes into contact with the upper end portion of the fixed iron core 50. At this time, in the process in which the armature 53 comes into contact with the upper end portion of the fixed iron core 50, the other end portion of the armature 53 comes into contact with the latch member 55 to rotate the latch member 55 clockwise. The latch member 55 holds the balance of the opening / closing mechanism 4 in a state where the force in the direction of breaking the balance of the opening / closing mechanism 4 is accumulated. When the latch member 55 is driven as described above, The force in the direction of breaking the balance is released, and the opening / closing mechanism 4 rotates the cross bar 30 clockwise to forcibly open the contact.

  At the time of forced opening, an arc is generated between the contacts, and this arc is attracted toward the shaft portion 30 a of the crossbar 30 by the electromagnetic force generated by the current flowing through the extension piece 22. Here, considering the electromagnetic force acting on an arbitrary point between the contacts, when the escape hole 22a is provided in the extension piece 22 as in the present embodiment, the escape hole 22a is not provided in the extension piece 22 Since the distance between the one point and the part through which the current flows in the terminal plate 2 is longer than the first point, the electromagnetic force in the direction toward the shaft portion 30a of the crossbar 30 at any one point between the contacts is weakened. .

  As described above, in the present embodiment, the terminal plate 2 is provided with the extended piece 22 that is substantially parallel to the contact / separation direction of the contact and faces each contact, and the extended piece 22 faces the operation range of the movable contact 3a. Since the escape hole 22a for escaping the arc gas generated at the forced opening is provided at the position, the gas pressure is reduced, and the cross bar 30 between the contacts is compared with the case where the terminal board 2 is not provided with the escape hole 22a. Since the electromagnetic force in the direction toward the shaft portion 30a is weakened, it is difficult for the arc to fly to the shaft portion 30a of the crossbar, and therefore the shaft portion 30a of the crossbar 30 is prevented from being burned by the arc generated during forced opening. Can do.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows embodiment of the contact device which concerns on this invention, (a) is a whole perspective view, (b) is a disassembled perspective view of a power supply side terminal part, (c) is a perspective view of a power supply side terminal part. . (A) is a perspective view which shows a closing state same as the above, (b) is a perspective view which shows an opening state same as the above. (A), (b) is sectional drawing which shows a closing state same as the above, (c), (d) is sectional drawing which shows an opening state same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 2 Terminal board 22 Extension piece 22a Escape hole 2a Fixed contact 3 Movable contactor 3a Movable contact 30 Crossbar 30a Shaft part 4 Opening / closing mechanism 40 Handle 41 Link member 5 Overcurrent interruption mechanism 55 Latch member A Power supply side terminal part B Load side terminal

Claims (1)

  A pair of terminal portions corresponding to input / output, a terminal plate having a fixed contact and connected to one terminal portion, and a movable contact having a movable contact contacting and separating from the fixed contact and connected to the other terminal portion Is housed in the container for each of one or more poles, and each movable contact is movable while holding a contact pressure spring between each movable contact to apply contact pressure when each movable contact contacts each fixed contact. By having a crossbar for supporting the contactor and operating each movable contactor in conjunction with each other, and a handle that can be rotated between an on position and an off position, and transmitting the rotation of the handle to the crossbar. An opening / closing mechanism composed of a plurality of link members that bring each movable contact into and out of each fixed contact, a latch member that maintains the balance of the opening / closing mechanism in a state in which the force in the direction that breaks the balance of the opening / closing mechanism is accumulated, a fixed contact, and a movable Latch when overcurrent flows between contacts A contact device having an overcurrent interrupting mechanism that drives the material to break the balance of the opening and closing mechanism and forcibly opens the movable contact from the fixed contact, and the crossbar has a shaft portion provided on itself. The movable contact as an axis is rotatable between a position where the movable contact is in contact with the fixed contact and a position where the movable contact is separated, and the terminal plate has an extension piece which is substantially parallel to the contact / separation direction of the contact and faces each contact. The contact piece is characterized in that the extended piece is provided with a relief hole for escaping arc gas generated during forced opening at a position facing the operating range of the movable contact.

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