JP2011142012A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lower-cost and space-saving circuit breaker with a switching mechanism part having improved durability. <P>SOLUTION: The circuit breaker includes a switching mechanism 40 constituted of a lower link 46 for driving a cross bar 30, a lever 44 to be turned in engagement with the latch of a tripping device 33 during tripping while being journaled to a bearing portion of a frame, an upper link 45 journaled to the lever 44 and joined to the lower link 46 via a spring pin 47, and constituting a toggle link together with the lower link 46, a main spring 48 joined at its driven side to the spring pin 47, and a handle arm 42 joined to the driving side of the main spring 48 and turnably journaled to the frame 43 fixed to a casing. The lever 44 including a lever turning shaft part 44a is formed from a single metal plate, and the lever turning shaft part 44a has a circular portion 44a2 whose center angle is greater than 180&deg;. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a circuit breaker such as a circuit breaker for wiring or an earth leakage breaker, and more particularly to an improvement in durability of an opening / closing mechanism.

In general circuit breakers, a quick contact mechanism using a well-known toggle link is adopted, and it is more advantageous for miniaturization because the lever's pivot shaft does not penetrate the mechanism part because the restriction of the main spring moving space is reduced. It is. Further, the rotation of the lever needs to be transmitted to the accessory device across the interphase wall. However, it is preferable that the member for transmitting the rotation of the lever is configured as close to the rotation shaft of the lever as possible in order to ensure insulation between the phases.
Due to such restrictions, in the conventional circuit breaker, a part of the lever is bent to form a rotating shaft (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2008-140692 (FIG. 8)

As described above, in the conventional circuit breaker, the section of the pivot shaft of the lever is substantially square, and the contact with the shaft hole is limited to the corner or end face, and the contact surface pressure increases, so the opening / closing operation is repeated. As a result, abnormal wear and misalignment occur.
It is also possible to form the lever's pivot shaft by burring instead of bending, but there is a limit to the launch height, and if there are other parts such as a toggle link between the lever and the frame There is a problem in that it is difficult to ensure the strength of the pivot shaft of the lever because it is necessary to drive out the plate thickness three times or more.
On the other hand, it is conceivable to join the rotating shaft composed of different parts to the lever, but it is difficult to satisfy the problems such as securing the joining space, dimensional accuracy and strength, and reducing the parts cost and assembly cost at the same time. there were.

  The present invention has been made to solve the above-described problems, and provides a circuit breaker that can improve the durability of an opening / closing mechanism.

  A circuit breaker according to the present invention includes a movable contact having a movable contact at one or both ends, a fixed contact contacting and moving away from the movable contact, a cross bar holding the movable contact and pivotally supported freely. The lower link that drives this crossbar, the lever that engages with the latch of the trip device, and is pivotally supported by the bearing portion of the frame when tripping, and the spring pin that is pivotally supported by this lever and is also pivoted to the lower link The main link is coupled to the lower link and forms a toggle link with the lower link, the main spring is coupled to the driven side of the spring pin, and the drive side of the main spring is coupled to be fixed to the casing of the circuit breaker. A handle arm pivotally supported by the frame, and the lever is formed of a single metal plate including the pivot shaft portion of the lever, and the pivot shaft portion has a central angle of 180 degrees. Ri and has a large arc-shaped portion.

  According to this invention, since the arcuate portion whose central angle is larger than 180 degrees is provided on the rotation shaft portion of the lever in the opening / closing mechanism portion and the contact with the bearing portion of the frame is the surface contact, the contact surface pressure is reduced. It is possible to improve the durability of the opening / closing mechanism.

It is a perspective view which shows the trip state of the circuit breaker in Embodiment 1 of this invention. It is side surface sectional drawing which shows the trip state of the circuit breaker in Embodiment 1 of this invention. It is side surface sectional drawing which shows the OFF state of the circuit breaker in Embodiment 1 of this invention. It is side surface sectional drawing which shows the ON state of the circuit breaker in Embodiment 1 of this invention. It is a principal part perspective view which extracts and shows the opening-closing mechanism part, movable contact, and crossbar from the circuit breaker in Embodiment 1 of this invention. It is a perspective view which shows the lever of the circuit breaker in Embodiment 1 of this invention. It is a side view which shows the lever of the circuit breaker in Embodiment 1 of this invention. It is a side view which shows the lever rotating shaft part of the lever of the circuit breaker in Embodiment 1 of this invention. It is a perspective view which shows mounting | wearing of the lever rotation transmission member to the switching mechanism part of the ON state of the circuit breaker in Embodiment 1 of this invention. It is explanatory drawing which shows the load concerning the lever of the circuit breaker in Embodiment 1 of this invention. It is a principal part enlarged view which shows the engaging part of the lever and latch of the circuit breaker in Embodiment 1 of this invention. It is a side view which shows the lever rotating shaft part of the lever of the circuit breaker in Embodiment 2 of this invention.

Embodiment 1 FIG.
1 is a perspective view showing a trip state of a circuit breaker according to Embodiment 1 of the present invention, FIG. 2 is a side sectional view showing a trip state, FIG. 3 is a side sectional view showing an off state, and FIG. 4 is an on state. FIG. 5 is a perspective view of the main part extracted from the open / close mechanism, the movable contactor, and the crossbar, FIG. 6 is a perspective view of the lever 44, and FIG. 7 is a side view of the same lever 44. 8 is a side view of the lever rotation shaft portion 44a, FIG. 9 is a perspective view showing attachment of the lever rotation transmission member 13 to the ON / OFF mechanism portion, and FIG. 10 is a direction of a load applied to the lever rotation shaft portion 44a. (A) shows an on state, (b) shows an off state, and (c) shows a trip state. FIG. 11 is an enlarged view of a main part showing an enlarged engagement portion 44b of the lever 44 with the latch 34.

  In FIG. 1, a circuit breaker 100 is configured by using a housing 10 including a base 11 and a cover 12 made of an insulating material. On the base 11, circuit breaker units 20A, 20B, and 20C for each of the three phases are arranged in parallel with each other, and an opening / closing mechanism unit 40 is arranged above the center circuit breaker unit 20B. The base 11 has a pair of outer walls 11A and 11B and a pair of partition walls 11C and 11D. A circuit breaker unit 20A is disposed between the outer wall 11A and the partition wall 11C, a circuit breaker unit 20B is disposed between the partition walls 11C and 11D, and a circuit breaker unit 20C is disposed between the partition wall 11D and the outer wall 11B. Is placed. The cover 12 covers the circuit breaker units 20A, 20B, and 20C of each phase on the base 11 and the opening / closing mechanism 40, and the operation handle 41 of the opening / closing mechanism 40 protrudes from the cover 12. In FIG. 1, the cover 12 cuts out portions covering the circuit breaker units 20 </ b> A and 20 </ b> B, and illustrates the inside thereof.

  The circuit interruption units 20A, 20B, and 20C for each phase are configured in the same manner, and specific configurations thereof are shown in FIGS. 2, 3, and 4. FIG. 2, 4 and 5 show the central circuit breaking unit 20B, but the other circuit breaking units 20A and 20C are configured in the same manner. 2, 3, and 4, the crossbar 30 is common to the circuit breaker units 20 </ b> A, 20 </ b> B, and 20 </ b> C for each phase, and is orthogonal to the circuit breaker units 20 </ b> A, 20 </ b> B, and 20 </ b> C for each phase. Are arranged on the base 11.

  The circuit breaker units 20A, 20B, and 20C for each phase include a power supply side terminal 24 provided on the base 11, a fixed contact 21 extended from the power supply side terminal 24, and a movable contact 22 that contacts and separates from the fixed contact 21. The movable contact 22 is provided at one end and is rotatably held by the crossbar 30; an overcurrent tripping device 33 connected to the movable contact 23; and an overcurrent tripping It has a load-side terminal 25 connected to the device 33 and provided on the base 11. When the movable contact 22 comes into contact with the fixed contact 21, the electrical circuit between the terminals 24 and 25 is turned on. When the movable contact 22 is separated from the fixed contact 21, the electrical circuit between the terminals 24 and 25 is turned off. It becomes.

  As shown in FIGS. 2, 3, and 4, the cross bar 30 is disposed at the bottom of the base 11 and extends so as to be orthogonal to the paper surface of FIGS. 2, 3, and 4. The cross bar 30 is rotated about its axis by the opening / closing mechanism 40, and the movable contacts 23 in the circuit breaker units 20A, 20B, and 20C of the respective phases are attached. When the cross bar 30 rotates about its axis, the movable contactors 23 of the circuit breaker units 20A, 20B, and 20C of the respective phases are simultaneously rotated. The contact 22 contacts and separates from the fixed contact 21.

  As shown in FIG. 5 in addition to FIGS. 2, 3, and 4, the opening / closing mechanism 40 includes a frame 43 formed by a pair of opposed frame plates and a rotational axis P on the frame 43. A substantially U-shaped handle arm 42 (not shown in FIG. 5; shown in FIGS. 2, 3, and 4) that is pivotally supported and fixed to the handle arm 42 and is manually operated. It is unitized by an operation handle 41 (not shown in FIG. 5; shown in FIGS. 2, 3 and 4). The inside is engaged with the latch 34 of the overcurrent tripping device 33 and is pivotally supported on the frame bearing portion 43a of the frame 43 by the rotating shaft 44a. The lever 44 is pivotally supported by the link support shaft Q. And a lower link 46 (not shown in FIG. 5; not shown in FIG. 5, but shown in FIGS. 2, 3 and 4) which is engaged with the upper link 45 via a spring pin 47. ), And a pair of main springs 48 stretched around the driven pin 48b and the drive side 48a on the handle arm 42, respectively.

  2, 3, and 4, the upper link 45 is rotatably supported at the upper end thereof by the link support shaft Q of the lever 44, and the lower link 46 has a lower end at the crossbar. 30 is rotatably connected. The operation handle 41 protrudes upward from the cover 12 and is rotated about the rotation axis P by manual operation. By the rotation of the operation handle 41, the handle arm 42 is also rotated around the rotation center point P together with the operation handle 41. The handle arm 42 is in the intermediate position in the trip state shown in FIG. 2, is in the left inclined position in the off state shown in FIG. 3, and is in the right inclined position in the on state shown in FIG.

  As shown in FIGS. 6 and 7, the lever 44 is formed of a single metal plate including the lever rotation shaft portion 44 a and is disposed on the inner surface side of each side plate of the handle arm 42. The lever rotation shaft portion 44a is formed by driving the lever rotation shaft portion to form an arc-shaped portion after bending a metal plate portion serving as the lever rotation shaft portion 44a by 90 degrees in the axial direction. . For example, as shown in FIG. 8, a cross section of the lever rotation shaft 44a of the lever 44 is formed in a substantially arc shape having a dogleg-shaped rotation transmission recess 44a1 by driving and a central angle larger than 180 degrees. Arc-shaped portion 44a2. The arcuate portion 44a2 serves as a contact portion that makes surface contact with the frame bearing portion 43a of the frame 43 in a wide range.

  Further, as shown in FIG. 9, the lever 44 has the protrusion 13 a of the lever rotation transmission member 13 fitted in the rotation transmission recess 44 a 1 of the lever 44. The lever rotation transmission member 13 transmits the rotation of the lever 44 to an internal accessory device or the like housed in the circuit breaker 100 during a trip.

  Further, since the axial length of the lever rotation shaft portion 44a is formed by driving after bending the metal plate, it can be formed larger than the thickness of the metal plate forming the lever 44. The rotating shaft portion can be formed even with a length more than double.

Next, on, off and trip operations of the circuit breaker 100 will be described.
As shown in FIG. 3, in the off state, the movable contact 22 is separated from the fixed contact 21, and the fixed contact 21 and the movable contact 22 are in the separated state. In the off state, the handle arm 42 is in the left inclined position, and the lower link 46 is in the lateral state. When the operation handle 41 is operated clockwise in the off state shown in FIG. 3, the handle arm 42 together with the operation handle 41 rotates clockwise around the rotation center point P, and the handle The arm 42 rotates to the right inclined position shown in FIG. By the rotation of the handle arm 42, the drive side 48 a of the main spring 48 moves in the clockwise direction around the rotation center point P of the handle arm 42. The movement of the drive side 48a of the main spring 48 changes the load direction of the main spring 48, and the spring pin 47 moves to the right from the position shown in FIG. As shown in FIG. 4, the movement of the spring pin 47 brings the lower link 46 into an upright state, and the cross bar 30 rotates in the clockwise direction, so that the movable contact 22 on the movable contact 23 is fixed to the fixed contact 21. Will be in the on state.

  In the on state shown in FIG. 4, when the operation handle 41 is operated in the counterclockwise direction, the handle arm 42 rotates together with the operation handle 41 in the counterclockwise direction around the rotation center point P. The handle arm 42 rotates to the left inclined position shown in FIG. By the rotation of the handle arm 42, the drive side 48 a of the main spring 48 moves counterclockwise about the rotation center point P of the handle arm 42. The movement of the drive side 48a of the main spring 48 changes the load direction of the main spring 48, and the spring pin 47 moves to the left from the position shown in FIG. By the movement of the spring pin 47, as shown in FIG. 3, the lower link 46 returns to the horizontal state, the cross bar 30 rotates counterclockwise, and the movable contact 22 on the movable contact 23 is fixed. It is separated from the contact 21 and is turned off.

  When the overcurrent tripping device 33 operates in the on state shown in FIG. 4, when the overcurrent tripping device 33 pushes and rotates the trip bar 35, the latch 34 is unlocked by the trip bar 35. As a result, the latch 34 is free to rotate, and the latch 34 and the lever 44 are disengaged. Since the lever 44 is always urged clockwise by the main spring 48, the lever 44 is rotated clockwise when the engagement with the latch 34 is released. By the rotation of the lever 44, the handle arm 42 is rotated from the right inclined position shown in FIG. 4 to the intermediate position shown in FIG. Due to the rotation of the handle arm 42, the drive side 48 a of the main spring 48 moves relatively to the right side of the spring pin 47, and an upward force starts to act on the spring pin 47. Due to the upward movement of the spring pin 47, the cross bar 30 is lifted upward, and the lower link 46 is in an intermediate standing state shown in FIG. 2, and the movable contact 22 on the movable contact 23 is opened from the fixed contact 21. The trip state shown in FIG. 2 is established.

  Next, the load F2 applied to the lever rotation shaft 44a will be described. As shown in FIG. 10, the load F <b> 2 applied to the lever rotation shaft 44 a is applied to the lever rotation shaft portion 44 a as a reaction force of the force F <b> 1 that the upper link 45 pushes up the link support shaft Q of the lever 44. Here, the force F1 that pushes up the link support shaft Q is urged by a pair of main springs 48 stretched around a spring pin 47 that connects the upper link 45 and the lower link 46.

  The lever rotates even in the on state of FIG. 10 (a), the off state of FIG. 10 (b), the trip state of FIG. 10 (c), and in the middle of the transition from the on state to the trip state. In order to reduce the contact surface pressure between the shaft portion 44a and the frame bearing portion 43a, the lever rotating shaft portion of the external force applied to the lever rotating shaft portion 44a in the cross section perpendicular to the axis of the lever rotating shaft portion 44a of the lever 44 is provided. The component in the direction perpendicular to 44a is configured such that the load F2 is always applied to the arcuate portion 44a2 of the lever rotation shaft portion 44a.

  As shown in FIG. 11, the engaging portion 44b of the lever 44 with the latch 34 is formed of a curved surface. When the overcurrent is detected and the tripping device 33 is operated, the latch 34 becomes free to rotate, and receives the load from the lever 44 and moves from the solid line 34-1 position to the two-dot chain line 34-2 position. At this time, the load applied to the latch 34 by the lever 44 changes from G1 to G2 due to the curved surface provided in the engaging portion 44b. At this time, the distance from the rotation axis center 34a of the latch 34 to the contact point between the lever 44 and the latch 34 as the action point changes from the length A before the movement to the length B after the movement. The load G2 after the movement is equal to or slightly larger than the load G1 before the movement, and the distance from the rotation axis 34a of the latch 34 to the action point is B (after movement) ≧ A (before movement). In the process of disengaging from 34, the rotational moment that the latch 34 receives from the lever 44 increases.

  According to the present embodiment, the lever 44 is formed of a single metal plate including the lever rotation shaft portion 44a, and the lever rotation shaft portion 44a is provided with an arcuate portion 44a2 having a central angle larger than 180 degrees. Therefore, the arcuate portion 44a2 is in surface contact with the frame bearing portion 43a of the frame 43 in a wide range, the contact surface pressure can be kept low, and the durability of the opening / closing mechanism portion during repeated operation can be improved. , Positional deviation can be suppressed.

  Further, since the axial length of the lever rotation shaft portion 44a is formed by driving after bending the metal plate, it can be larger than the thickness of the metal plate forming the lever 44. It is possible to sufficiently secure the connecting portion.

  Further, in each of the on state, the off state, and the trip state, in a cross section perpendicular to the axis of the lever rotation shaft portion 44a of the lever 44, an external force applied to the lever rotation shaft portion 44a is perpendicular to the lever rotation shaft portion 44a. Since the component always applies a load to the arcuate portion 44a2 of the lever rotation shaft portion 44a, the contact surface pressure of both the lever rotation shaft portion 44a and the frame bearing portion 43a can be suppressed, and the opening / closing mechanism portion during repeated operation The durability of the opening / closing mechanism is improved.

  Further, since the lever rotating shaft portion 44a is formed by bending after a single metal plate is bent, the strength of the shaft portion can be improved, and the misalignment at the time of joining and the accumulation of component dimensional errors are reduced. It is possible to reduce the part cost and the assembly cost.

  Further, the lever rotation shaft 44a of the lever 44 is provided with a rotation transmission recess 44a1 by driving, and the protrusion 13a of the lever rotation transmission member 13 is fitted into the rotation transmission recess 44a1, so that the lever rotation transmission member 13 is fitted. The relative rattling in the rotation direction of the lever rotation shaft portion 44a can be efficiently suppressed in a limited space.

  Further, since the lever rotation transmission member 13 is provided in the rotation transmission recess 44a1 of the lever 44, the rotation of the lever 44 at the time of trip can be easily transmitted to an internal accessory device or the like disposed in the circuit breaker 100. Can do.

  Further, by providing a curved surface at the engaging portion 44b of the lever 44 with the latch 34, the tripping device 33 is activated by detecting an overcurrent, and the latch 34 is locked in the process of releasing the engagement with the latch. Since the rotational moment applied to the latch 34 is increased without increasing the load applied to the tripping device 33, the trip operation can be stabilized and the reliability of the circuit breaker can be improved.

  In this embodiment, an example of a one-point cut-off type circuit breaker having a movable contact at one end of the movable contact has been described. However, a two-point cut-off type circuit breaker having movable contacts at both ends of the movable contact is described. Needless to say, the opening / closing mechanism in the present embodiment can be applied to the container, and the same effects as in the present embodiment can be obtained.

Embodiment 2. FIG.
FIG. 12 is a side view showing the lever rotation shaft portion 44a in the second embodiment.
In the present embodiment, as shown in FIG. 12, the arcuate portion 44a2 of the lever rotation shaft portion 44a has an arc portion 44a3 having a central angle of about 180 degrees and an extension portion on the circumscribed circle of the arc portion. The contact portion 44 a 4 is provided and contacts the frame bearing portion 43 a of the frame 43. The central angle of the arcuate portion 44a2 is configured to be greater than 180 degrees within a range in which the arc portion 44a3 and the contact portion 44a4 are added. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In the first embodiment, the end surface, which is a cut surface of a single metal plate that forms the lever 44, is also subjected to a forming process such as driving or cutting into an arc, but in the present embodiment, the end surface of the lever 44 is The contact portion 44a4 that contacts the frame bearing portion 43a of the frame 43 is used as it is. It is better that the tip of the contact portion 44a4 is not point-contacted with the frame bearing portion 43a, for example, by chamfering or cutting.

  According to the present embodiment, the lever 44 is formed of a single metal plate including the lever rotation shaft portion 44a, and the lever rotation shaft portion 44a is provided with an arcuate portion 44a2 having a central angle larger than 180 degrees. Therefore, the arc-shaped portion 44a2 contacts the frame bearing portion 43a of the frame 43 in a wide range, the contact surface pressure can be kept low, and the durability of the opening / closing mechanism portion during repeated operation can be improved. Misalignment can be suppressed.

  Moreover, since the process of the end surface of the single metal plate which forms the lever 44 was simplified, a part of process of forming the lever rotating shaft part 44a can be omitted, and the cost can be reduced.

  In the above description, the circuit breaker has been described. However, it is a matter of course that this type of switch can be used in general, and even if minor changes are made, it does not depart from the scope of the invention.

21 fixed contact, 22 movable contact, 23 movable contact, 30 crossbar,
33 Tripping device, 34 Latch, 42 Handle arm, 43 Frame,
44 lever, 44a lever rotating shaft part, 44a2 arcuate part,
47 Spring pin, 48 Main spring,
45 Upper link, 46 Lower link, 100 Circuit breaker.

Claims (8)

A movable contact having a movable contact at one or both ends, a fixed contact contacting and moving away from the movable contact, a cross bar holding the movable contact and pivotally supported freely, and a lower drive for driving the cross bar A link and a lever that engages with the latch of the tripping device and is pivotally supported by the bearing portion of the frame at the time of trip, and is pivotally supported by the lever and coupled to the lower link via a spring pin. An upper link that forms a toggle link together with the lower link, a main spring coupled to the driven side of the spring pin, and a drive side of the main spring coupled to a frame fixed to the casing of the circuit breaker A handle arm freely pivoted,
The lever is formed of a single metal plate including a pivot shaft portion of the lever, and the pivot shaft portion has an arcuate portion having a central angle larger than 180 degrees. 2. The circuit breaker according to claim 1, wherein the lever includes a rotation transmission concave portion that is provided on a rotation shaft portion of the lever and transmits the rotation of the lever. 3. The circuit breaker according to claim 2, further comprising a lever rotation transmission member that is fixed to the rotation shaft portion of the lever and has a protrusion that is fitted into the rotation transmission recess. 3. The circuit breaker according to claim 1, wherein the arc-shaped portion provided on the rotation shaft portion of the lever is an arc. 4. The arc-shaped portion provided on the pivot shaft portion of the lever is provided on an arc portion forming a part of the arc-shaped portion and an extension portion on a circumscribed circle of the arc portion, and is provided on the bearing portion of the frame. The circuit breaker according to claim 1, further comprising a contact portion that contacts the circuit breaker. The circuit breaker according to claim 1 or 2, wherein the pivot shaft portion of the lever has an axial length larger than a plate thickness of the lever. In the cross section perpendicular to the axis of the pivot shaft of the lever, the component in the direction perpendicular to the axis of the external force applied to the lever shaft is always directed to the arcuate portion provided in the pivot shaft of the lever. The circuit breaker according to claim 1 or 2, wherein the circuit breaker is provided. The engagement surface of the lever with the latch is formed in a curved surface, and the rotational moment that the latch receives from the lever increases in the process of releasing the engagement with the latch. 2. The circuit breaker according to 2.

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