JP5478756B2 - Circuit breaker - Google Patents

Description

  The present invention relates to a circuit breaker for wiring circuit breakers and earth leakage circuit breakers, and more particularly to a structure of a current breaker.

  Conventionally, in a circuit breaker, not only the function of opening and closing the electric circuit by operating the operation handle provided in the circuit breaker, that is, not only the switch function but also the burning of electric wires and load equipment due to overcurrent etc. It plays a role of cutting off the electric circuit to prevent it. One of the parts for satisfying these functions of the circuit breaker is a movable contact that contacts the stationary contact in the closed state and separates from the fixed contact in the opened state. For the connecting conductor connected to this movable contact, a flexible shunt made of copper flat knitted wire or laminated thin plates is used for small circuit breakers with a rated current of 30 to 100A subject to space restrictions. Has been.

  However, this shunt has a problem of fatigue disconnection in the opening / closing function described above, and the opening / closing life has to be limited. Therefore, as one means for improving the open / close life, the movable contact and the connection conductor are brought into sliding contact, and the contact spring disposed outside the connection conductor is used to increase the contact pressure between the movable contact and the connection conductor. An energization mechanism is known. The electrical contact between the movable contact and the connecting conductor is generally called a shuntless energization mechanism because a shunt is not used.

  Since this shuntless energization mechanism necessarily has a sliding surface, for example, the possibility that dust or the like enters the sliding surface cannot be denied. In addition, the possibility that the sliding surface may be oxidized or nitrided cannot be denied. If dust enters the sliding surface, oxidation of the sliding surface, etc., the electrical resistance of the sliding surface will increase, causing abnormal heat generation of the circuit breaker, impairing the reliability of the circuit breaker. It will be.

  Further, there is known a two-point circuit breaker which is a shuntless energization mechanism and opens / closes at two points (see, for example, Patent Document 1). This circuit breaker will be described with reference to FIGS. The circuit breaker 101 includes a first fixed contact 102 having a first fixed contact 121, a second fixed contact 103 having a second fixed contact 131, and a first fixed contact 121 facing the first fixed contact 121. And a movable contact 104 having a second movable contact 142 facing the first movable contact 141 and the second fixed contact 131 and performing an opening / closing operation.

  The first fixed contact 102 and the second fixed contact 103 are arranged in parallel, and the movable contact 104 has two movable contacts at the U-shaped arm tip. The movable contact 104 rotates around a shaft 107 to perform an opening / closing operation. In this circuit breaker 101, arcs are generated between the first fixed contact 121 and the first movable contact 141 and between the second fixed contact 131 and the second movable contact 142 at the time of opening, but the mutual arcs are generated. Since the current direction is opposite, an electromagnetic repulsive force is generated and the arcs move in the G direction. Due to this arc, the contact melts and evaporates and is consumed, and when the arc is unevenly distributed outside the contact, the consumable part concentrates outside the contact and the contact is reduced. Therefore, contact failure tends to occur at the time of closing. In order to prevent this contact failure, a magnetic plate 108 is provided between the two pairs of fixed contact and movable contact, and this magnetic plate 108 weakens the electromagnetic repulsive force and reduces the outward movement of the arc. Yes.

  However, in such a circuit breaker 101, since the extension of the arc is prevented by the magnetic plate 108, an increase in the arc voltage is suppressed and a high current limiting effect cannot be obtained.

JP 2007-280928 A

  An object of the present invention is to solve the above problem, and to provide a circuit breaker in which an arc between contacts expands at the time of opening and a high current limiting effect is obtained, and damage to the contacts is suppressed.

  In order to achieve the above object, the first aspect of the present invention provides a first fixed contact having a first fixed contact, a second fixed contact having a second fixed contact, and the first fixed contact. A circuit breaker comprising: a first movable contact facing the first movable contact; and a second movable contact facing the second fixed contact; and a movable contact that opens and closes. Between the first movable contact and the second movable contact, there is a parallel electric circuit portion that is substantially parallel to a straight line connecting the first fixed contact and the first movable contact at the time of contact opening, When the contact of the movable contact opens from each contact of the first fixed contact and the second fixed contact, the current direction in the parallel electric circuit portion to be interrupted by the opening and the first The direction of current from the fixed contact to the first movable contact is opposite, and the parallel circuit portion The magnetic field of the flowing current acts on the arc between the first fixed contact and the first movable contact, and the second fixed contact has the second movable contact and the second fixed contact when the contact is opened. When the contact of the movable contact is opened from each contact of the first fixed contact and the second fixed contact, The current direction in the second parallel circuit portion to be interrupted by opening is opposite to the current direction from the second movable contact to the second fixed contact, and the second parallel circuit portion The magnetic field of the current that flows through the arc acts on the arc between the second movable contact and the second fixed contact.

  According to a second aspect of the present invention, in the circuit breaker according to the first aspect of the present invention, the circuit breaker further includes a casing that covers the fixed contact and the movable contact, and the casing is the second movable contact at the time of opening. With respect to a straight line connecting the first fixed contact and the second fixed contact, an exhaust port is provided on the side opposite to the second parallel electric circuit portion.

  According to a third aspect of the present invention, in the circuit breaker according to the first or second aspect, when the second parallel electric circuit section is viewed from the second movable contact, the second parallel electric circuit section A part or all of the second parallel electric circuit portion is covered with an insulator so that part or the whole is not visible.

  According to the first aspect of the present invention, since the arc between the first fixed contact and the first movable contact is extended by the magnetic field of the current flowing through the parallel electric path portion, a high current limiting effect is obtained. Damage to the fixed contact and the first movable contact is suppressed. In addition, since the arc between the second movable contact and the second fixed contact is extended by the magnetic field of the current flowing through the second parallel electric path section, a high current limiting effect can be obtained. Damage to the fixed contact 2 is suppressed.

  According to the invention of claim 2, since the gas generated by the arc between the second movable contact and the second fixed contact is discharged from the exhaust port, the arc is extended toward the exhaust port by the gas. Since the gas exhaust direction and the direction of the Lorentz force that the arc receives from the current flowing through the second parallel circuit portion are the same, the arc further expands to obtain a high current limiting effect, and the second movable contact and the second The damage of the fixed contact is further suppressed.

  According to invention of Claim 3, since the 2nd parallel electric circuit part is covered with the insulator, when a movable contactor is removed, it is between a 2nd parallel electric circuit part and a 2nd movable contact. Short circuit is prevented, and damage to the second parallel circuit portion is prevented.

The lineblock diagram of the circuit breaker concerning a 1st embodiment of the present invention. (A) is the side view at the time of closing of the circuit breaker, (b) is the side view at the time of opening of the circuit breaker. The side view of the circuit breaker which concerns on the 2nd Embodiment of this invention. The side view of the circuit breaker which concerns on the 3rd Embodiment of this invention. The block diagram of the circuit breaker which concerns on the 4th Embodiment of this invention. (A) is the side view at the time of closing of the circuit breaker, (b) is the side view at the time of opening of the circuit breaker. The block diagram of the circuit breaker which concerns on the 5th Embodiment of this invention. The side view of the circuit breaker which concerns on the 6th Embodiment of this invention. The side view of the circuit breaker which concerns on the 7th Embodiment of this invention. The side view of the circuit breaker which concerns on the 8th Embodiment of this invention. The block diagram of the conventional circuit breaker. The front view of the circuit breaker.

(First embodiment)
A circuit breaker 1 according to a first embodiment of the present invention will be described with reference to FIG. The circuit breaker 1 includes a first fixed contact 2 connected to one of the commercial power source or the load device, a second fixed contact 3 connected to the other of the commercial power source or the load device, and a first fixed A movable contact 4 that opens and closes with the contact 2 and the second fixed contact 3, and a housing 5 (indicated by a one-dot chain line; not shown in the following) covering each contact and the like. The first fixed contact 2 and the second fixed contact 3 are provided in parallel in two upper and lower stages, the first fixed contact 2 has a first fixed contact 21 on the upper surface, The second stationary contact 3 has a second stationary contact 31 on the upper surface. The movable contact 4 is U-shaped, has a first movable contact 41 opposed to the first fixed contact 21 on the lower surface of the upper side, and a second opposed to the second fixed contact 31 on the lower surface of the lower side. A movable contact 42 is provided.

  The movable contact 4 has a parallel electric circuit portion 43 between the upper side and the lower side, which is substantially parallel to a straight line connecting the first fixed contact 21 and the first movable contact 41 when the contact is opened. The current direction in the parallel electric circuit portion 43 and the current direction from the first fixed contact 21 to the first movable contact 41 are opposite to each other. The movable contact 4 also has arc runners 44 and 45 at the top ends of the upper side and the lower side, respectively, and the second fixed contact 3 has an arc runner 32 at the tip. The movable contact 4 slides up and down to perform an opening / closing operation. The circuit breaker 1 detects the current and voltage in the second fixed contact 3 by a detection unit (not shown), and when an abnormality such as an overcurrent is detected, the tripping unit (not shown) moves the movable contact. The child 4 is slid and removed, and the electric circuit is interrupted.

  Next, the breaking operation of the circuit breaker 1 will be described with reference to FIGS. 2 (a) and 2 (b). As shown in FIG. 2A, at the time of closing, the first fixed contact 21 is in contact with the first movable contact 41 and the second fixed contact 31 is in contact with the second movable contact 42. Electric power is transmitted to the load device via the first fixed contact 2, the movable contact 4, and the second fixed contact 3. Subsequently, when an energization abnormality such as overcurrent occurs, the movable contact 4 is pulled upward from the first fixed contact 2 and the second fixed contact 3 as shown in FIG. At this time, an arc is generated between the first fixed contact 21 and the first movable contact 41 and between the second movable contact 42 and the second fixed contact 31.

  If the current direction in the arc generated between the first fixed contact 21 and the first movable contact 41 at this time is the A direction, the current direction in the parallel circuit portion 43 is the B direction. In the vicinity of the arc, a magnetic field is generated with the paper surface facing from the front to the back. This magnetic field causes the arc to expand in an arc shape under the Lorentz force in the C direction. Along with this, the arc voltage increases, and a high current limiting effect is obtained. For this reason, the arc disappears quickly, and damage to the first fixed contact 21 and the first movable contact 41 is suppressed. Further, since the arc moves to the arc runner 44 and the first fixed contact 2 which are the tips of the movable contact 4 by Lorentz force, the one-side reduction of the first movable contact 41 and the first fixed contact 21 is reduced. This makes it difficult for contact failure to occur. Moreover, since the 1st stationary contact 2, the 2nd stationary contact 3, and the movable contact 4 are arrange | positioned at the up-down direction, the width | variety of the circuit breaker 1 can be narrowed.

  According to the present embodiment, since the arc between the first fixed contact 21 and the first movable contact 41 is extended by the magnetic field of the current flowing through the parallel electric path portion 43, a high current limiting effect is obtained. Damage to the fixed contact 21 and the first movable contact 41 is suppressed.

(Second Embodiment)
A circuit breaker according to a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the description of the same configuration as the circuit breaker of the first embodiment is omitted. In addition to the configuration of the first embodiment, the circuit breaker 1 of the present embodiment has an exhaust port 51 for exhausting gas generated by the arc in the housing 5 (see FIG. 1). The exhaust port 51 is provided in a direction opposite to the parallel electric path portion 43 with respect to a straight line connecting the first fixed contact 21 and the first movable contact 41 when the contact is opened. The movable contact 4 is pulled off and an arc is generated between the first fixed contact 21 and the first movable contact 41, and the gas generated by the arc is discharged from the exhaust port 51. Since the exhaust direction of this gas and the direction of the Lorentz force that the arc receives from the current flowing through the parallel electric path portion 43 are the same, the arc is further extended as compared with the first embodiment.

  According to the present embodiment, since the gas generated by the arc is discharged from the exhaust port 51, the arc is further extended toward the exhaust port 51 by the gas to obtain a high current limiting effect, and the first fixed contact 21 and the damage to the first movable contact 41 are further suppressed.

(Third embodiment)
A circuit breaker according to a third embodiment of the present invention will be described with reference to FIG. In addition to the configuration of the first embodiment, the circuit breaker 1 of the present embodiment includes an insulator 61 that prevents a short circuit between the first fixed contact 21 and the parallel electric circuit portion 43. The insulator 61 covers the entire parallel circuit section 43 so that the parallel circuit section 43 cannot be seen when the parallel circuit section 43 is viewed from the first fixed contact 21. The insulator 61 is made of an insulating material such as nylon or PBT, for example, and is fixed to the parallel electric circuit portion 43.

  According to the present embodiment, since the parallel electric circuit portion 43 is covered with the insulator 61, a short circuit between the parallel electric circuit portion 43 and the first fixed contact 21 when the movable contact 4 is removed. Is prevented, and damage to the parallel electric circuit portion 43 is prevented. The insulator 61 may cover a part of the parallel electric path portion 43.

(Fourth embodiment)
A circuit breaker according to a fourth embodiment of the present invention will be described with reference to FIGS. In addition to the configuration of the first embodiment, the circuit breaker 1 according to the present embodiment includes a first fixed contact 21 between the first fixed contact 21 and the parallel circuit portion 43 at the time of closing and at the time of opening. The first fixed insulator 62 for shielding the parallel electric circuit portion 43 from the first fixed insulator 62 is provided. The fixed insulator 62 shields the parallel electric circuit portion 43 so that the parallel electric circuit portion 43 cannot be seen when the parallel electric circuit portion 43 is viewed from the first fixed contact 21.

  The movable contact 4 of the present embodiment has an extended electric circuit portion 46 that rises upward from the upper side, and a connecting portion 47 that connects the parallel electric circuit portion 43 to the extended electric circuit portion 46. The first fixed insulator 62 has an L-shape, and is arranged so as to be positioned below the space surrounded by the parallel electric circuit portion 43, the extended electric circuit portion 46, and the connecting portion 47 and the first fixed contact 2. It is attached to the chassis (not shown) of the circuit breaker 1. The first fixed insulator 62 is made of an insulating material such as nylon or PBT, for example. With such a configuration, even when the movable contactor 4 performs an opening / closing operation, the first fixed insulator 62 is connected to the parallel electric path portion 43 and the lower side of the movable contactor 4 with the first fixed contact 21 and the first fixed contact. It can be shielded from the child 2.

  According to the present embodiment, since the parallel electric path portion 43 is shielded from the first fixed contact 21, when the movable contact 4 is pulled off, the parallel electric path portion 43 is between the parallel electric path portion 43 and the first fixed contact 21. Is prevented, and the parallel electric path portion 43 is prevented from being damaged. Further, since the first fixed insulator 62 is attached not to the movable contact 4 but to the chassis, there is little possibility that the first fixed insulator 62 is detached by the opening / closing operation of the movable contact 4, and the circuit breaker 1. Reliability is improved. Moreover, when the side length parallel to the parallel electric circuit part 43 of the 1st fixed insulator 62 is shortened, the movable contactor 4 may be the same shape as 1st Embodiment. In that case, the first fixed insulator 62 is attached so that a part of the parallel electric circuit portion 43 cannot be seen when the parallel electric circuit portion 43 is viewed from the first fixed contact 21. Further, the first fixed insulator 62 is not limited to the L shape, and may be an I shape without the lower side of the first fixed contact 2.

(Fifth embodiment)
A circuit breaker according to a fifth embodiment of the present invention will be described with reference to FIG. The circuit breaker 1 of the present embodiment has a second fixed insulator 63 that guides the opening / closing operation of the movable contact 4 in addition to the configuration of the fourth embodiment. The fixed insulator 63 is attached to the chassis on the side opposite to the first fixed insulator 62 with respect to the parallel electric circuit portion 43, and the parallel electric circuit portion 43 is sandwiched between the fixed insulator 63 and the first fixed insulator 62. Then, the opening / closing operation of the movable contact 4 is guided. The second fixed insulator 63 is made of an insulating material such as nylon or PBT, for example.

  According to this embodiment, since the opening / closing operation of the movable contact 4 is guided by the first fixed insulator 62 and the second fixed insulator 63, the opening / closing operation of the movable contact 4 is stabilized, and the circuit The reliability of the circuit breaker 1 is improved.

(Sixth embodiment)
A circuit breaker according to a sixth embodiment of the present invention will be described with reference to FIG. In addition to the configuration of the first embodiment, the circuit breaker 1 of the present embodiment includes a second parallel electric circuit portion 33 that extends an arc between the second movable contact 42 and the second fixed contact 31. 2 fixed contacts 3. The second parallel electric circuit portion 33 rises upward from the second fixed contact 3, is substantially parallel to a straight line connecting the second movable contact 42 and the second fixed contact 31, and the second The current direction in the parallel electric path portion 33 and the current direction from the second movable contact 42 to the second fixed contact 31 are opposite to each other.

  According to this embodiment, when the movable contactor 4 performs the opening operation, if the direction of the current in the arc between the second movable contact 42 and the second fixed contact 31 is the D direction, Since the direction of the current in the parallel electric circuit section 33 is the E direction, a magnetic field is generated in the vicinity of the arc from the back to the front. As in the first embodiment, this magnetic field causes the arc to receive a Lorentz force in the F direction and expands in an arc shape, so that a high current-limiting effect is obtained, and the second movable contact 42 and the second fixed contact 31 are damaged. It can be suppressed. Moreover, since the arc moves to the arc runner 45 that is the tip of the movable contact 4 or the arc runner 32 that is the tip of the second fixed contact 3 by Lorentz force, the second movable contact 42 and the second fixed contact Decrease of 31 is reduced, and contact failure of the contact is less likely to occur.

(Seventh embodiment)
A circuit breaker according to a seventh embodiment of the present invention will be described with reference to FIG. In addition to the configuration of the sixth embodiment, the circuit breaker 1 of the present embodiment has an exhaust port 52 for exhausting gas generated by the arc in the housing 5. The exhaust port 52 is provided in a direction opposite to the second parallel electric circuit portion 33 with respect to a straight line connecting the second movable contact 42 and the second fixed contact 31 when the contact is opened. This exhaust port 52 is generated by an arc when the movable contact 4 is pulled off and an arc is generated between the second movable contact 42 and the second fixed contact 31 as in the second embodiment. The exhausted gas is discharged from the exhaust port 52. Since the gas is exhausted from the exhaust port 52, the arc is extended toward the exhaust port 52 by the gas. Since the gas exhaust direction and the direction of the Lorentz force that the arc receives from the current flowing through the second parallel circuit portion 33 are the same, the arc is further extended as compared with the sixth embodiment. As a result, a high current limiting effect is obtained, and damage to the second movable contact 42 and the second fixed contact 31 is further suppressed.

(Eighth embodiment)
A circuit breaker according to an eighth embodiment of the present invention will be described with reference to FIG. In addition to the configuration of the sixth embodiment, the circuit breaker 1 of the present embodiment has an insulator 64 that prevents a short circuit between the second movable contact 42 and the second parallel electric circuit portion 33. Yes. The insulator 64 covers the entire second parallel electric circuit portion 33 so that the second parallel electric circuit portion 33 cannot be seen when the second parallel electric circuit portion 33 is viewed from the second movable contact 42. Yes. The insulator 64 is made of an insulating material such as nylon or PBT, for example, and is fixed to the second parallel electric circuit portion 33. The insulator 64 may cover a part of the second parallel electric path portion 33.

  According to this embodiment, since the second parallel electric circuit portion 33 is covered with the insulator 64, the second movable contact 42 and the second parallel electric circuit portion are removed when the movable contact 4 is removed. Short circuit with 33 is prevented, and damage to the second parallel circuit portion 33 is suppressed. The insulator 64 may guide the opening / closing operation of the movable contact 4. Thereby, the opening / closing operation | movement of the movable contactor 4 is stabilized, and the reliability of the circuit breaker 1 improves.

  In addition, this invention is not restricted to the structure of the said embodiment, A various deformation | transformation is possible in the range which does not change the meaning of invention. For example, the above embodiments may be combined. In each embodiment, a single-pole circuit breaker is shown, but a plurality of poles may be used.

DESCRIPTION OF SYMBOLS 1 Circuit breaker 2 1st stationary contact 21 1st stationary contact 3 2nd stationary contact 31 2nd stationary contact 33 2nd parallel electrical circuit part 4 Movable contact 41 1st movable contact 42 2nd Movable contact 43 parallel electric path portion 5 casing 51, 52 exhaust port 61, 64 insulator 62 first fixed insulator 63 second fixed insulator

Claims (3)

A first fixed contact having a first fixed contact; a second fixed contact having a second fixed contact; a first movable contact facing the first fixed contact; and the second fixed contact. In a circuit breaker comprising a movable contact having a second movable contact facing the contact and performing an opening and closing operation,
The movable contact is parallel between the first movable contact and the second movable contact and is substantially parallel to a straight line connecting the first fixed contact and the first movable contact when the contact is opened. Has an electrical circuit,
When the contact of the movable contact opens from each contact of the first fixed contact and the second fixed contact, the current direction in the parallel electric circuit portion to be interrupted by the opening and the first The current direction from the fixed contact to the first movable contact is opposite, and the magnetic field of the current flowing through the parallel circuit portion acts on the arc between the first fixed contact and the first movable contact,
The second fixed contact has a second parallel electric circuit portion that is substantially parallel to a straight line connecting the second movable contact and the second fixed contact at the time of contact opening.
When the contact of the movable contact opens from each contact of the first fixed contact and the second fixed contact, the current direction in the second parallel circuit portion to be interrupted by the opening and the current The current direction from the second movable contact to the second fixed contact is opposite, and the magnetic field of the current flowing through the second parallel circuit portion is between the second movable contact and the second fixed contact. Circuit breaker characterized by acting on arc. A housing that covers each of the fixed contacts and the movable contacts;
The casing has an exhaust port on a side opposite to the second parallel electric path portion with respect to a straight line connecting the second movable contact and the second fixed contact at the time of opening. The circuit breaker according to claim 1.   When the second parallel electric circuit portion is viewed from the second movable contact, part or all of the second parallel electric circuit portion is not visible so that part or all of the second parallel electric circuit portion is not visible. The circuit breaker according to claim 1 or 2, wherein the circuit breaker is covered with an insulator.

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