JP2009004273A - Contact device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact device in which wear of both a movable contact and a fixed contact due to arc generated upon opening contacts can be suppressed. <P>SOLUTION: An electrode member 50 which is electrically connected to a movable contact 11 and is separated from a fixed contact 10 is installed at a closer part to a base end side than the movable contact 11 of an opposed face to the fixed contact 10 in a movable contactor 9. An arc runner 48 which is electrically connected to the fixed contact 10 and is separated from the movable contact 11 and the electrode member 50 is installed at a closer part of a base end side than the fixed contact 10 of the movable contactor 9 of an opposed face to the movable contact 11 in a fixed contact plate 7. The spacing between the electrode plate 50 and the arc runner 48 becomes smaller than the spacing between the fixed contact 10 and the movable contact 11 during the time the movable contactor 9 moves from a closed contact position in which the movable contact 11 is in contact with the fixed contact 10 to the open contact position so that the movement amount from the fixed contact plate 7 may be larger on the tip side than the base end side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  Conventionally, as this kind of contact device A, for example, as shown in FIG. 3, a fixed contact plate 7 provided with a fixed contact 10 and a movable contact 11 provided with a movable contact 11 at a position facing the fixed contact 10 at the tip. A contact 9 is provided in the housing 2 made of synthetic resin, and the movable contact 9 is moved from the closed position where the movable contact 11 is brought into contact with the fixed contact 10, and the moving amount with respect to the fixed contact plate 7 is proximal at the distal end side. There is a configuration in which a contact is opened by moving it to be larger than the side and moving it to an opening position (see, for example, Patent Document 1).

  In this type of contact device A, when the contact is opened with current flowing between the fixed contact 10 and the movable contact 11, an arc is generated between the fixed contact 10 and the movable contact 11 when the contact is opened. This arc may cause a problem such that the fixed contact 10 and the movable contact 11 are consumed.

Therefore, in the contact device A described in Patent Document 1, the electrode piece 50 that is electrically connected to the movable contact 11 is provided at a portion of the movable contact 9 that faces the fixed contact 10. The electrode piece 50 is configured such that the distance between the fixed contact 10 and the electrode piece 50 is smaller than the distance between the fixed contact 10 and the movable contact 11 while the movable contact 9 is moved from the closed position to the open position. The movable contact 11 is disposed adjacent to the base end side (here, the pivot shaft 12 side). Therefore, an arc generated at the time of opening is between the movable electrode 11 and the fixed electrode 10 and between the electrode piece 50 and the fixed electrode 10 during the period in which the movable contact 9 moves from the closed position to the open position. It can move and the consumption of the movable contact 11 by an arc can be suppressed.
Japanese Patent No. 2734615 (page 2-3, FIG. 1)

  However, even if it is invention of patent document 1, the arc which generate | occur | produces in the stationary contact 10 at the time of opening cannot be prevented. Therefore, although consumption of the movable contact 11 due to arc can be suppressed, consumption of the fixed contact 10 due to arc cannot be suppressed.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a contact device that can suppress wear due to an arc generated at the time of opening both the movable contact and the fixed contact.

  According to the first aspect of the present invention, a fixed contact plate provided with a fixed contact, a movable contact provided with a movable contact at a portion facing the fixed contact at the tip, and a movable contact with respect to the fixed contact plate are predetermined. The movable contact and the fixed contact are opened by moving the movable contact from the closed position where the movable contact is in contact with the fixed contact to the open position. An electrode piece that is a contact device and is electrically connected to the movable contact and spaced apart from the fixed contact at a portion of the movable contact that faces the fixed contact on the base end side of the movable contact The fixed contact plate is electrically connected to the fixed contact on the base contact side of the movable contact with respect to the movable contact and the electrode piece. A spaced arc runner is provided. Ri, the distance between the electrode pieces and the arc runner is movable contact is equal to or smaller than the distance between the fixed contact and the movable contact during movement from the closing position to the opening position.

  According to this configuration, the distance between the electrode piece provided on the movable contact and the arc runner provided on the fixed contact plate is such that the fixed contact and the movable contact are moved while the movable contact moves from the closed position to the open position. Therefore, even if an arc is generated between the movable contact and the fixed contact at the time of opening, this arc will be generated between the electrode piece and the arc runner within the period during which the movable contact moves to the opening position. Move in between. Therefore, compared with the case without an arc runner, the time for generating an arc between the fixed contact and the movable contact is shortened, and the consumption by the arc can be suppressed for both the movable contact and the fixed contact.

  According to a second aspect of the present invention, in the first aspect of the present invention, the arc runner is arranged on the fixed contact plate so that the arc contactor faces the arc runner in the electrode piece when the movable contactor is in the open position. It is characterized in that it is inclined.

  According to this configuration, since the arc runner is substantially parallel to the surface of the electrode piece facing the arc runner when the movable contactor is in the open position, the electrode piece and the arc runner are disposed over the entire area of the electrode piece facing the arc runner. The distance can be made substantially uniform. Therefore, it is possible to prevent the arc generated between the electrode piece and the arc runner from concentrating on one part of the electrode piece or the arc runner. As a result, the arc current flow range can be expanded to reduce the time required for arc extinction. It can be shortened.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the support mechanism is a movable contact by a pivot shaft that is located at a position closer to the base end side than the electrode piece of the movable contact. The movable contact is a portion of the movable contact that faces the fixed contact on the base end side of the electrode piece, and the movable contact is in the open position. In some cases, an insulating piece made of an insulating material is provided at a position on a straight line connecting the arc runner and the pivot shaft.

  According to this configuration, since the insulating piece is interposed between the arc runner and the pivot shaft when the movable contactor is in the open position, it moves between the movable contact and the fixed contact between the electrode piece and the arc runner. It is possible to prevent the arc from moving further toward the pivot shaft. Therefore, it is possible to avoid a problem that the movable contact cannot rotate with respect to the movable frame due to the pivotal shaft being burned by the arc.

  In the present invention, by providing the electrode piece and the arc runner, even when an arc is generated between the movable contact and the fixed contact at the time of opening, this arc is within the period during which the movable contact moves to the opening position. Since it moves between the electrode piece and the arc runner, it is possible to suppress arc consumption for both the movable contact and the fixed contact.

  In this embodiment, the contact device used for the circuit breaker which opens a contact and performs circuit interruption when a short circuit current is detected is illustrated. Below, the whole structure of this circuit breaker is demonstrated easily with reference to FIG. In the following description, the upper, lower, left and right in FIG. Note that this circuit breaker is used with the upper side in FIG. 2 as the upper side.

  The circuit breaker 1 has terminal devices 3 to which electric wires can be connected to both left and right ends of a housing 2 made of synthetic resin, and the contact device A is located at a position near one (left) terminal device 3 in the housing 2. It has. In addition to the contact device A, the housing 2 includes a current detection device (not shown) for detecting a short-circuit current flowing through the contact device A, and a contact device A in conjunction with the operation of the handle 4 protruding from the upper surface of the housing 2. And an opening / closing mechanism 5 for opening and closing the door. The current detection device is composed of an electromagnet device. When the contact device A is in a closed state, the switching mechanism 5 detects that the current detection device detects a short-circuit current and an amateur (not shown) of the current detection device operates. The trip mechanism 6 forcibly opening the contact device A is provided.

  The contact device A includes a fixed contact plate 7 extending from the one terminal device 3 into the housing 2 and a coil (not shown) of a current detection device and the other terminal device (not shown). And a movable contact 9 electrically connected via a flexure 8 (see FIG. 2B). Here, a fixed contact 10 having a rectangular plate shape is fixed to the upper surface of the tip of the fixed contact plate 7 facing the movable contact 9, and fixed to the lower surface of the tip of the movable contact 9 facing the fixed contact 10. A rectangular plate-shaped movable contact 11 capable of contacting and separating from the contact 10 is fixed. The movable contact 9 is pivotally supported on a synthetic resin movable frame 13 by a pivot shaft 12 inserted in the center portion, and the spring receiving pin 14 and the movable frame 13 inserted in the other end portion. It is urged to rotate by a contact pressure spring 16 (see FIG. 2B) provided between the spring projection 15 provided on the inner surface. The movable frame 13 is pivotally supported by the housing 2 so that the movable frame 13 is rotatable with respect to the housing 2. Thus, the movable frame 13 and the shaft portion 17 and the housing 2 support the movable contactor 9 so as to be movable within a predetermined range (between an open position and a closed position described later) with respect to the fixed contact plate 7. The supporting mechanism is configured.

  Here, the urging direction of the movable contact 9 by the contact pressure spring 16 is determined by the positional relationship between the spring protrusion 15 and the spring receiving pin 14 corresponding to both ends of the contact pressure spring 16 and the pivot shaft 12. For example, in the open state shown in FIG. 2A and the closed state shown in FIG. 2B, the spring receiving pin 14 is positioned above the straight line connecting the spring protrusion 15 and the pivot shaft 12, The movable contact 9 is urged counterclockwise in the figure with respect to the movable frame 13.

  The trip mechanism 6 of the opening / closing mechanism unit 5 includes a trip link 19 pivotally supported with respect to the housing 2 by a pivot shaft 18 provided at one end, and first and second connected to the trip link 19. Links 20 and 21 and a spring 22 made of a tension coil spring. The trip link 19 is positioned at a predetermined position shown in FIG. 2 by engaging an engaging portion 23 provided at the other end with the latch portion 24, and the first portion is connected to the center portion via a link shaft 25. One end of the link 20 is connected. The other end of the first link 20 is connected to one end of the second link 21 by a connecting shaft 26, and the other end of the second link 21 is connected to the movable contact 9 by a pivot shaft 12. The The spring 22 is stretched between a connecting shaft 26 that connects both the links 20 and 21 and a pin 28 held by a lever 27 coupled to the handle 4.

  Next, the operation of the circuit breaker 1 having the above-described configuration will be briefly described.

  In the state where the handle 4 is tilted to the right as shown in FIG. 2A, the spring 22 is positioned on the right side of the link shaft 25 that connects the trip link 19 and the first link 20. The pair of links 20 and 21 in FIG. 5 are folded by the bias of the spring 22, and the pivot shaft 12 held by the movable frame 13 is pulled up. As a result, the movable contact 9 is located at the opening position shown in FIG. 2A, the movable contact 11 is separated from the fixed contact 10, and the contact device A is in the open state.

  On the other hand, when the handle 4 is moved to the left from the state shown in FIG. 2A, the spring 22 moves past the position of the link shaft 25 that connects the trip link 19 and the first link 20. The connecting shaft 26 is pulled leftward by the urging, and the pair of links 20 and 21 are extended as shown in FIG. As a result, the movable frame 13 rotates counterclockwise in the drawing and the pivot shaft 12 is lowered, and the movable contact 9 moves to the closed position shown in FIG. When the provided movable contact 11 comes into contact with the fixed contact 10, the contact device A is in a closed state. At this time, the movable contact 9 is urged counterclockwise in the figure by the contact pressure spring 16 to ensure contact pressure between the fixed contact 10 and the movable contact 11.

  Although illustration is omitted, when the current detection device detects a short-circuit current in the closed state shown in FIG. 2B, the amateur of the current detection device operates and shifts to a trip state. That is, when the armature is operated, the engagement between the engagement portion 23 of the trip link 19 and the latch portion 24 is released, and the trip link 19 is rotated counterclockwise in the figure by the bias of the spring 22. When the link shaft 25 connecting the trip link 19 and the first link 20 moves to the left side of the spring 22, the urging force of the spring 22 is reversed, and the pair of links 20 and 21 are folded and moved. The frame 13 rotates clockwise in the figure, and the pivot shaft 12 is pulled up. As a result, the movable contact 9 at the closed position moves so that the amount of movement with respect to the fixed contact plate 7 is larger at the distal end side than at the proximal end side, and moves to the open position, and the movable contact 11 is moved to the fixed contact 10. The contact device A is forcibly opened by being separated from the contact.

  The circuit breaker 1 described above includes a contact device A, a terminal device 3 and a current detection device for each pole, and a current detection device for each pole by using an opening / closing mechanism 5 including a handle 4 in common for each pole. The device and the contact device A are configured to work together.

  Next, the configuration of the contact device A of the present embodiment will be described in detail with reference to FIG.

  The fixed contact plate 7 is made of a conductive material (for example, copper or copper alloy), and has a terminal piece 31 in which a screw hole 30 into which a terminal screw 29 (see FIG. 2) of the terminal device 3 is screwed is formed. A connecting piece 32 extending downward from the right edge of the terminal piece 31 along the thickness direction of the terminal piece 31, and a contact piece 33 extending from the tip edge of the connecting piece 32 to the opposite side (right side) of the terminal piece 31. Is formed in a substantially Z shape, and is fitted into the housing 2. The fixed contact 10 is made of a conductive material (for example, silver or silver alloy) having higher arc resistance than the fixed contact plate 7 and is fixed to the upper surface of the contact piece 33. A semicircular portion 34 having a semicircular shape in plan view protrudes from both sides in the width direction of the tip of the contact piece 33.

  An exhaust barrier 35 formed in a plate shape from an insulating material having elasticity and an exhaust plate 36 formed in a plate shape from an insulating material are provided at the end of the connection piece 32 on the contact piece 33. 35 is erected along the connecting piece 32 with the connecting piece 32 side. The exhaust barrier 35 and the exhaust plate 36 are formed larger in the vertical dimension than the connecting piece 32, and protrude upward from the terminal piece 31. Here, a plurality of exhaust holes 37 are provided in a portion of the exhaust plate 36 protruding above the terminal piece 31, and the exhaust barrier 35 is mounted on the exhaust plate 36 so as to close the exhaust hole 37. An engagement piece (not shown) is formed at a substantially central portion of the exhaust barrier 35, and this engagement piece is engaged with an engagement hole 38 penetrating the substantially central portion of the exhaust plate 36. As a result, the exhaust plate 36 is mounted. Further, a fixing hole (not shown) for mounting a later-described U-shaped magnetic plate 39 is provided below the engagement hole 38 in the exhaust plate 36. The exhaust barrier 35 and the exhaust plate 36 are attached to the housing 2 by inserting both sides into a groove 40 formed in the housing 2, and the terminal chamber 41 in which the terminal device 3 is disposed in the housing 2 and the contact device A are disposed. The contact chamber 42 is partitioned.

  A U-shaped magnetic plate 39 is attached to one surface of the exhaust plate 36 opposite to the exhaust barrier 35. The U-shaped magnetic plate 39 includes a rectangular plate-like base piece 43 along the exhaust plate 36 and a pair of side pieces 44 respectively extending from both sides of the base piece 43 to the opposite side of the exhaust plate 36. The cross section along the contact piece 33 is formed in a U-shape, and is fixed to the exhaust plate 36 by inserting a fitting protrusion (not shown) protruding from the base piece 43 into the fixing hole of the exhaust plate 36. . Here, the U-shaped magnetic plate 39 is fixed to the exhaust plate 36 so as to leave a predetermined gap S1 between the lower surface and the contact piece 33, and further, a portion of the contact piece 33 to which the fixed contact 10 is fixed is fixed. A position in a plane along the contact piece 33 is determined so as to be surrounded by the base piece 43 and the both side pieces 44. The U-shaped magnetic plate 39 and the fixed contact plate 7 are electrically insulated by the exhaust barrier 35 interposed between the front end surface of the fitting protrusion and the connecting piece 32.

  A conductive plate 45 that is electrically connected to the fixed contact plate 7 is attached to the tip (right end) of the contact piece 33. The conductive plate 45 is made of a conductive material (for example, iron, stainless steel, etc.) having a melting temperature higher than that of the fixed contact plate 7, and a fitting groove (not shown) formed in each semicircular portion 34 of the contact piece 33. A coupling piece 47 having a coupling claw 46 to be inserted into the contact piece 33, and an arc runner 48 projecting to the right from the tip edge of the contact piece 33. Here, the arc runner 48 is inclined at a predetermined angle with respect to the contact piece 33 so as to lower the tip side.

  On the other hand, the movable contact 9 is formed in a plate shape orthogonal to the connecting piece 32 and the contact piece 33 of the fixed contact plate 7 with a conductive material (for example, copper or copper alloy). It is pivotally supported with a pivot shaft 12 provided in the section as a fulcrum. Here, in the movable contact 9, a contact mounting portion 49 having a thickness dimension larger than that of the other portion is formed in a portion of the front end portion (left end portion) facing the fixed contact 10. The movable contact 11 is fixed. The movable contact 11 is made of a conductive material (for example, silver or a silver alloy) having higher arc resistance than the movable contact 9.

  An electrode piece 50 electrically connected to the movable contact 11 is attached to the movable contact 9. The electrode piece 50 is formed of a conductive material (for example, iron, stainless steel, etc.) having a melting temperature higher than that of the movable contact 9, and is fitted into a first coupling groove 51 formed on the lower surface of the movable contact 9. The coupling protrusion 52 is provided. The first coupling groove 51 penetrates the movable contact 9 in the thickness direction and is formed in a so-called dovetail shape that becomes wider as the depth increases. The coupling protrusion 52 of the electrode piece 50 is also formed in the first coupling groove 51. It is formed in a corresponding shape. Therefore, the electrode piece 50 is fixed by fitting the first coupling protrusion 52 into the first coupling groove 51 from one side in the thickness direction of the movable contact 9. As shown in FIG. 2, the electrode piece 50 faces the fixed contact 10 and the arc runner 48 at a distance from each other so as to always face the movable contact 11 with respect to the movable contact 11 (here, the pivot shaft 12 side). ). Here, the distance between the electrode piece 50 and the arc runner 48 is set to be smaller than the distance between the fixed contact 10 and the movable contact 11 at least in the open state shown in FIG. A concave portion 53 is formed on the surface (lower surface) of the electrode piece 50 facing the fixed contact 10 and the arc runner 48. When the contact device A is in a closed state, the concave piece 53 causes the electrode piece 50 and the conductive plate 45 (coupled) to be connected. A gap is secured between the piece 47 and the arc runner 48).

  Here, the inclination angle of the arc runner 48 with respect to the contact piece 33 is set so that the arc runner 48 is disposed along the surface of the electrode piece 50 facing the arc runner 48 in the open state shown in FIG. . Thus, in the open state, the opposing surfaces of the electrode piece 50 and the arc runner 48 are substantially parallel, and the distance between the electrode piece 50 and the arc runner 48 in the entire area of the electrode piece 50 facing the arc runner 48. Can be arranged almost uniformly.

  Furthermore, an insulating piece 54 made of an insulating material is attached to the central portion of the lower surface of the movable contact 9. The insulating piece 54 has a second coupling protrusion 56 that is fitted into a second coupling groove 55 formed on the lower surface of the movable contact 9. The second coupling groove 55 is formed in a dovetail shape like the first coupling groove 51, and the coupling protrusion 56 of the insulating piece 54 is formed in a shape corresponding to the second coupling groove 55. However, the opening surface of the first coupling groove 51 is set wider than that of the second coupling groove 55, so that the first coupling protrusion 52 is formed wider than the second coupling protrusion 56. Here, the insulating piece 54 is a position opposite to the movable contact 11 with respect to the electrode piece 50 on the lower surface of the movable contact 9, and in the open state of the contact device A as shown in FIG. It is arranged at a position on a straight line connecting the arcrunner 48 and the pivot shaft 12. In the present embodiment, the electrode piece 50 and the insulating piece 54 are movable so that the lower surface of the movable contact 9 and the lower surfaces of the electrode piece 50 and the insulating piece 54 are substantially flush with each other in the closed state of the contact device A. It is mounted in a recess 57 formed on the lower surface of the contact 9.

  By the way, in the contact device A of this embodiment, as shown in FIG. 1, the insulating material having a higher heat resistance than the synthetic resin material forming the housing 2 is formed in a plate shape around the fixed contact 10 in the housing 2. The formed guard wall 58 is erected. FIG. 1A shows a state in which one guard wall 58 is removed.

  The guard walls 58 are respectively erected at positions on both sides of the contact piece 33 in the width direction of the fixed contact plate 7 and spaced from the inner surface of the housing 2 by the gap S2. The vertical dimension of the guard wall 58 is set to be larger than the connecting piece 32 and smaller than the exhaust barrier 35 and the exhaust plate 36, and the moving range of the movable contact 11 is restricted within the vertical dimension of the guard wall 58. . Here, the guard wall 58 is formed in a U-shape by fitting mounting protrusions 59 projecting from the side pieces 44 of the U-shaped magnetic plate 39 away from each other into mounting holes 60 penetrating the guard wall 58. The structure fixed to the type | mold magnetic board 39 is employ | adopted. Further, a plurality (three in this case) of rectangular air holes 61 are provided in a portion of the guard wall 58 that is above the lower end of the electrode piece 50 in the open state so that the rectangular air holes 61 are arranged vertically. Yes. A notch 62 is provided at the lower end of the guard wall 58 so as to avoid interference with the semicircular portions 34 projecting on both sides of the contact piece 33.

  According to the contact device A having the above-described configuration, when the current is opened between the fixed contact 10 and the movable contact 11 in the closed state, the contact between the fixed contact 10 and the movable contact 11 is opened. An arc is generated. This arc is generated between the movable contact 11 and the fixed contact 10 immediately after the movable contact 11 is separated from the fixed contact 10, but the movable contact 9 is moved from the closed position of FIG. ), The distance between the movable contact 11 and the fixed contact 10 increases as the distance between the movable contact 11 and the fixed contact 10 increases, and the distance between the movable contact 11 and the fixed contact 10 increases. When the distance between the electrode piece 50 and the arc runner 48 becomes larger (that is, when the distance between the electrode piece 50 and the arc runner 48 becomes smaller than the distance between the movable contact 11 and the fixed contact 10), the electrode piece 50 And the arc runner 48.

  In short, the arc generated between the movable contact 11 and the fixed contact 10 moves between the electrode piece 50 and the arc runner 48 within the period in which the movable contact 9 moves from the closed position to the open position, resulting in the result. In particular, as compared with the configuration without the arc runner 48, the time for generating an arc between the movable contact 11 and the fixed contact 10 is shortened, and both the movable contact 11 and the fixed contact 10 can be prevented from being consumed by the arc. it can. Here, since the insulating piece 54 is provided at a position between the arc runner 48 and the pivot shaft 12 in the open state, the arc generated at the time of opening moves between the electrode piece 50 and the arc runner 48. However, the arc 48 does not further move to the vicinity of the pivot shaft 12. Therefore, it is possible to avoid a problem that the pivotal support shaft 12 as the rotation axis of the movable contact 9 with respect to the movable frame 13 is burned by the arc, so that the movable contact 9 cannot be rotated with respect to the movable frame 13.

  In the open state, the opposing surfaces of the electrode piece 50 and the arc runner 48 are substantially parallel, and the distance between the electrode piece 50 and the arc runner 48 is substantially uniform over the entire area of the electrode piece 50 facing the arc runner 48. Therefore, it is possible to prevent the arc generated between the electrode piece 50 and the arc runner 48 from being concentrated on one place of the electrode piece 50 or the arc runner 48. Thereby, compared with the case where an arc concentrates on one place of the electrode piece 50 or the arc runner 48, the range through which the arc current flows can be expanded and the time required for arc extinction can be shortened.

  Further, in the present embodiment, since the exhaust hole 37 is provided in the exhaust plate 36 that partitions the contact chamber 42 and the terminal chamber 41 of the housing 2, the air expands in the contact chamber 42 due to the thermal energy of the arc when the electrode is opened. Even so, the air is exhausted to the terminal chamber 41 through the exhaust hole 37 of the exhaust plate 36 while pushing the exhaust barrier 35 away from the exhaust plate 36.

  In the present embodiment, an arc is generated between the movable contact 11 and the fixed contact 10 and further between the electrode piece 50 and the arc runner 48 at the time of opening in the energized state as described above. Since the guard wall 58 is erected, the guard wall 58 can prevent heat generated when the arc is generated from being transmitted directly to the housing 2. In addition, since there is a gap S2 between the guard wall 58 and the inner surface of the housing 2, heat transfer from the guard wall 58 to the housing 2 is also hindered by the gap S2. Therefore, it is difficult for the heat of the arc to be transmitted to the housing 2, and the synthetic resin material forming the housing 2 around the fixed contact 10 can be prevented from being vaporized by the heat of the arc. Furthermore, even if the synthetic resin material forming the housing 2 around the fixed contact 10 is vaporized, the synthetic resin material is blocked by the guard wall 58 around the fixed contact 10 and adheres to the fixed contact 10. Never do. Therefore, the synthetic resin material does not adhere to the fixed contact 10, and as a result, there is an effect that poor contact between the fixed contact 10 and the movable contact 11 is less likely to occur.

  Furthermore, since the guard wall 58 has a plurality of air holes 61 at a position above the lower end of the electrode piece 50 in the open state, the air expanded by the thermal energy of the arc through the air holes 61 is opened. It is possible to escape outside the space surrounded by the guard wall 58. That is, the air hole 61 is provided above the arc generation position (between the movable contact 11 and the fixed contact 10 or between the electrode piece 50 and the arc runner 48) at the time of opening, so that an arc is generated. High-temperature air sometimes expanded by heat energy can be efficiently released from the air holes 61. Therefore, it is possible to prevent the problem that the air expanded by the heat of the arc expands in the space surrounded by the guard wall 58 and the guard wall 58 is deformed.

  In the present embodiment, the arc is generated in a portion surrounded by the base piece 43 and the both side pieces 44 of the U-shaped magnetic plate 39, so that the U-shaped magnetic plate 39 is made a part of the magnetic path by the arc current. A magnetic field is generated, and the arc is extended toward the base piece 43 by the magnetic field, whereby the time required for arc extinction is shortened.

  In the above embodiment, the contact device A used for the circuit breaker 1 is illustrated as an example of the contact device A of the present invention. However, the contact device A of the present invention is not limited to the circuit breaker 1 having the above-described configuration. It is also possible to apply to other devices.

The structure of the principal part of embodiment of this invention is shown, (a) is a perspective view of the state which removed the movable contact, (b) is a perspective view of the state which attached the movable contact. The structure of the principal part of a circuit breaker same as the above is shown, (a) is sectional drawing of an open state, (b) is sectional drawing of a closed state. It is the partially broken perspective view which shows the principal part of a prior art example.

Explanation of symbols

7 Fixed Contact Plate 9 Movable Contact 10 Fixed Contact 11 Movable Contact 12 Pivot Shaft 13 Movable Frame 48 Arclanner 50 Electrode Piece 54 Insulation Piece A Contact Device

Claims (3)

  A fixed contact plate provided with a fixed contact, a movable contact provided with a movable contact at a portion facing the fixed contact at the tip, and a movable contact supported in a predetermined range with respect to the fixed contact plate A contact device in which the movable contact and the fixed contact are opened by moving the movable contact from the closed position where the movable contact is in contact with the fixed contact to the open position. An electrode piece that is electrically connected to the movable contact and is spaced apart from the fixed contact is provided on a portion of the contact surface of the contact that faces the fixed contact that is closer to the base end than the movable contact. An arc runner that is electrically connected to the fixed contact and separated from the movable contact and the electrode piece is provided on a portion of the surface facing the movable contact at the base end side of the movable contact with respect to the fixed contact. Electrode piece and arm Distance between runners contact device movable contactor is characterized stationary contact and be smaller than the distance between the movable contact during movement from the closing position to the opening position.   The arc runner is inclined with respect to the fixed contact plate so as to be along a surface of the electrode piece facing the arc runner when the movable contact is in the open position. The contact device described.   The support mechanism includes a movable frame that rotatably supports the movable contact by a pivot shaft that is located at a position closer to the base end side than the electrode piece of the movable contact. Of the surface facing the fixed contact, the portion closer to the base end than the electrode piece, and at a position on the straight line connecting the arc runner and the pivot shaft when the movable contactor is in the open position. The contact device according to claim 1, wherein an insulating piece made of an insulating material is provided.

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