JP2910843B2 - Circuit breaker - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker that trips a control mechanism by operating an electromagnetic device to open a circuit opening / closing mechanism. 2. Description of the Related Art In this type of apparatus, a control mechanism for maintaining a circuit opening / closing mechanism in a closed state by operating an operating body is tripped by an operation of an electromagnetic device.
The electromagnetic device attracts the armature by a magnetic force generated at the time of abnormality, for example, when an overcurrent flows, and moves the armature to act on the control mechanism to trip the control mechanism. In such a device, it is required that the circuit opening and closing mechanism be surely opened to interrupt the circuit in the event of an abnormality in order to protect the load and prevent an electrical accident. That is, at the time of abnormality, first, it is necessary that the armature of the electromagnetic device surely moves and acts on the control mechanism. Also, since this type of device is often installed in a relatively small case,
It is desired that the assemblability is easy. Conventionally, as a technique relating to the structure of an electromagnetic device, there is one disclosed in Japanese Patent Application Laid-Open No. 48-28972 (prior art 1). FIG. 4 is a sectional side view of the prior art 1, and FIG. 5 is a partially enlarged perspective view of the same. In this case, an armature 43 is provided to face a magnetic pole 42 of a magnetic core in an electromagnetic device 41 provided in a case. This armature 4
3 is rotatably supported by a frame 45 of the electromagnetic device 41 via a holding shaft 44. Also, armature 43
The spring is biased by a tone bar 46 attached to the holding shaft 44 so as to separate from the magnetic pole 42. The tone bar 46 has an armature 4 at one end.
3 and the other end is locked to the frame 45. 47, 47 are circuit opening / closing mechanisms, one of which is connected to a power terminal, and the other of which is connected to a load terminal via an electromagnetic device 41. Reference numeral 48 denotes a control mechanism, which closes the circuit opening / closing mechanism 47 by operating the operation body 49, and trips when the electromagnetic device 41 operates in an abnormal state to open the circuit opening / closing mechanism 47. That is, the control mechanism 48 controls the electromagnetic device 4
A latch body facing the first armature;
When the armature 43 is sucked, the trip occurs because the latch body 50 is pressed. [0005] Another prior art is disclosed in
There is one disclosed in Japanese Patent No. 106068 (prior art 2). FIG. 6 is a perspective view of a part of the prior art 2. As shown in FIG.
Also in this case, an armature 63 is provided facing the magnetic pole 62 of the magnetic core in the electromagnetic device 61.
Is rotatably supported by the frame 64 of the electromagnetic device 61. The armature 63 is separated from the magnetic pole 62 by a tension spring 65 provided between the intermediate portion of the armature 63 and the frame 64. Reference numeral 66 denotes a latch body of a control mechanism (not shown).
Facing. The control mechanism is a circuit opening / closing mechanism (not shown)
Open / close control. In both of the prior arts 1 and 2, since the latch body of the control mechanism is pressed by the relatively distal end of the armature, the length from the rotation supporting portion of the armature to the pressing portion can be increased. It is easy to obtain the required pressing force. However, the prior art 1 has the following problems because the tone bar 46 is used for biasing the armature 43. (1) At the time of assembly, the holding shaft 44 is passed through the frame 45 while being inserted into the tone bar 46, and one end of the tone bar 46 is locked to one side of the armature 43, and the other end is locked to the frame 45. Must. However, these operations must be performed on small parts, in a small space, and against the spring force of the tone bar 46. For this reason, the workability is extremely poor and the productivity is deteriorated, so that it is unavoidable that the cost becomes high. (2) Since the holding shaft 44 is required because the tone bar 46 is used, the number of parts increases and the cost is increased in this respect. (3) As described above, one end of the tone bar 46 is locked to one side of the armature 43, and the other end is locked to one side of the frame 45. A force that leans toward the heart is applied. As a result, the suction force is lost when the electromagnetic device 41 is sucked,
The smoothness of the rotation of the armature 43 is impaired,
Operational stability may be impaired. In the prior art 2, since one end of the tension spring 65 is locked to the rotation support portion side from the surface of the armature 63 facing the magnetic pole 62, the following problem occurs. (1) Since the tension spring 65 is stretched between the frame 64 and the intermediate portion of the armature 63 in a narrow space, the length thereof is short. In the case of the same material and the same winding diameter, the shorter the length,
The spring constant increases. Therefore, the prior art 2 satisfies both of the following requirements: the armature 63 is separated from the magnetic pole 62 by a required tensile force in a normal state, and the latch body 66 is pressed by the armature 63 by the attractive force of the electromagnetic device 61 in an abnormal state. It will be very difficult. That is, in this type of device, the armature 63 needs to be separated from the magnetic pole 62 by a certain tensile force so as not to undesirably press the latch body 66 due to vibration or the like in a normal state. Also, in the event of an abnormality, the armature 16 is attracted by the attraction force of the electromagnetic device 61 while resisting the spring force of the tension spring 65.
3 must act on the latch body 66 reliably. Therefore, reducing the spring constant is advantageous in satisfying the respective requirements in the normal state and the abnormal state. On the other hand, in the case of the tension spring 65 having a short length and a large spring constant as in the prior art 2, if the armature 63 is pulled with a predetermined force at all times, a considerably large suction force is applied in the event of an abnormality. Need to be done. However, it is difficult to design a large attraction force of the electromagnetic device. That is, the circuit breaker is abnormal (for example, overcurrent)
A predetermined delay time is provided between the occurrence of an abnormality and the circuit opening / closing operation in accordance with the level of the error. As the level of the abnormality (for example, overcurrent) increases, the circuit is opened with a shorter delay time. Therefore, if the attraction force of the electromagnetic device 61 is simply designed to be relatively large, another problem arises that, for example, a short-time large current flowing at the time of starting the motor or the like is activated before the predetermined delay time is reached. On the other hand, in order to be able to suck with an abnormally small force, in particular, it is necessary to reduce the normal tensile force. However, in this case, as described above, the latch body is undesirably pressed due to vibration or the like, and malfunctions. Therefore, the normal pulling force is set to an appropriate value. In this case, even if the suction force for sucking the armature 63 of the electromagnetic device 61 is slightly smaller than the designed value, or the tension spring 65 does not work. If the length is slightly less than the designed value, the tension spring 65 cannot be extended by a required amount. For this reason, the electromagnetic device 61
Therefore, it is difficult to reliably rotate the armature 63 until the latch body 66 is pressed by the suction force, and a reliable circuit opening / closing operation cannot be obtained. Alternatively, it is necessary to strictly control the attraction force of the electromagnetic device 61 and the dimensions of the extension spring 65, which makes the device expensive. (2) Since one end of the tension spring 65 is provided at an intermediate portion of the armature 63, one end of the tension spring 65 rubs against the surface of the armature 63. Therefore, this also makes it difficult to stabilize the amount of displacement with respect to the pulling force, or causes loss of the suction force, thereby impairing the operation stability. SUMMARY OF THE INVENTION It is an object of the present invention to provide a circuit breaker which can obtain a stable and reliable shut-off characteristic, is easy to assemble, can reduce the number of parts, and has a surface area corresponding to the hole. According to the present invention, there is provided a circuit opening / closing mechanism having an operating body, a swingable contact arm having a movable contact and urged in a direction away from the fixed contact,
A magnetic core having a magnetic pole at one end, a winding for applying a magnetic flux to the magnetic core, a frame magnetically coupled to the magnetic core, a rising end at a distal end, a base end rotatably held by the frame, and a magnetic pole. An armature disposed opposite to the armature, and a tension spring that is stretched between the frame and the rising piece of the armature so as to be spaced apart from the armature and exerts a spring force to separate the armature from the magnetic pole; And a control mechanism for maintaining the circuit opening and closing mechanism in a closed state by operating the operating body and opening the circuit opening and closing mechanism by rotating the armature. Features. In the present invention, the control mechanism may be any mechanism that can normally maintain the circuit opening / closing mechanism in a closed state, and can trip and open the circuit opening / closing mechanism when the electromagnetic device is activated in the event of an abnormality. Such a control mechanism includes:
Well-known ones can be used, and those skilled in the art can appropriately configure them. As means for locking the tension spring, known means can be used. For example, a small hole is formed in each of the rising pieces of the frame and the armature, and the small hole can be locked. In the circuit breaker according to the present invention, when an abnormality occurs, for example, when an overcurrent flows, the armature is attracted to the magnetic pole by the attraction force of the electromagnetic device. This causes the armature to rotate and act on the control mechanism. Therefore,
The control mechanism trips and opens the circuit switching mechanism to shut off the circuit. The tension spring is stretched between the rising piece of the frame and the tip of the armature,
Its length is formed longer than that of the prior art 2. Therefore, the spring constant of the tension spring decreases. Therefore, it is easy to satisfy both of the following: the armature is separated from the magnetic pole by a required tensile force in a normal state, and the armature is caused to act on the control mechanism by an attractive force of the electromagnetic device in an abnormal state. That is, there is no malfunction due to normal operation, particularly vibration, etc., and in the event of an abnormality, a relatively small suction force reliably acts on the control mechanism. This allows
Even if there are parts variations in the electromagnetic device and the tension spring, the variations can be absorbed and a required amount of the armature can be sucked by the suction force of the electromagnetic device in the event of an abnormality. Therefore, the operation of the armature and the operation of the control mechanism are stabilized. Further, the tension spring does not rub against the surface of the armature, and does not cause loss of suction force or unstable spring force. In assembling, the required parts are assembled in any order, and the armature is supported by the frame, and a tension spring is clamped between the frame and the rising piece of the armature by stopping each end of the armature. Put on. Hereinafter, one embodiment of the present invention will be described. FIG. 1 is a sectional side view of one embodiment of the present invention,
FIG. 2 is an enlarged exploded perspective view of the main part, and FIG. 3 is an enlarged sectional view of the main part. Reference numeral 1 denotes a case, which comprises a base 2 having a closed surface and a cover 3 for covering the opening of the base 2. The case 1 is provided with a power supply terminal 4 and a load terminal 5. Reference numeral 6 denotes a circuit opening / closing mechanism capable of electrically opening and closing the power terminal 4 and the fixed terminal 5. The circuit opening / closing mechanism 6 includes a fixed contact 7, a contact arm 8, and a contact arm 8 arranged in a conductive state with the power terminal 4.
, And has a movable contact 9 facing the fixed contact 7. The contact arm 8 is rotatably supported on the shaft 10. Reference numeral 11 denotes an operation body, for example, an operation handle, which is rotatably supported by a shaft 12 and which closes the circuit opening / closing mechanism 6 when operated. Reference numeral 13 denotes a control mechanism that maintains the state of the circuit opening / closing mechanism 6 closed by the operation of the operation body 11 and trips to open the circuit opening / closing mechanism 6 by the operation of an electromagnetic device described later. Hereinafter, the control mechanism 13 of the present embodiment will be described in detail. A first link body 14 is rotatably connected to the distal end of the operating body 11, and an opening / closing body 15 pressed by the first link body 14 is provided. The opening / closing body 15 has an opening 16 through which the contact arm 8 passes, and the inclined upper surface is in contact with the lower end of the first link body 14. Further, a compression coil spring 17 is provided between the contact arm 8 and the base 2 for applying an elastic force in a direction to open the circuit opening / closing mechanism 6. As a means for applying the elastic force in this manner, the elastic force of the contact arm 8 itself may be used as is well known.
Further, the second link body 1 that rotates with the shaft 18 as a support shaft
9. A spring 20 for urging the second link body 19 clockwise is provided. A pin 21 is provided upright at the free rotation end of the second link body 19. On the other hand, the latch body 22
Is rotatably supported by a shaft 23, and an engagement portion 24 that engages with the pin 21 is formed at one end of the latch body 22. Therefore, the latch body 22 rotates about the shaft 23 so that the engaging portion 24 engages with or disengages from the pin 21. Reference numeral 25 denotes an electromagnetic device. The electromagnetic device 25 of the present embodiment will be described in detail below. A magnetic core 26 has a magnetic pole 27 at one end. Reference numeral 28 denotes a winding through which a current flowing through the contact arm 8 and the load terminal 5 flows, and applies a magnetic flux to the magnetic core 26. Reference numeral 29 denotes a frame which is magnetically coupled to the magnetic core 26 to form a part of a magnetic path. At the tip of the frame 29 is a long and narrow Sekiguchi 30
And a step-like supporting portion 3 located at a part of the closing edge of the closing 30
1 and an edge portion 32 cut and raised from the opening 30 and inclined.
A bent piece 32 having a and a small hole 33 are formed. An armature 34 has a stopper 35 formed at one end to contact the frame 29, and has a rising piece 36 at the other end. The rising piece 36 is formed in, for example, a U-shape. Further, a small hole 37 is formed in the rising piece 36. Reference numeral 38 denotes a tension spring, which is a small hole 33 of the frame 29 and a rising piece 3 of the armature 34.
6 are locked with the small holes 37. An electromagnet 13 is provided upright in the case 1, and the frame 12 is provided along a magnetic core of an iron core 14 of the electromagnet 13. The frame 12 in the present embodiment is connected to the load terminal 5 and serves as a yoke of the power supply electromagnet 13, and the shaft 10 is attached to the frame 12. With such a structure, the contact arm 8 and thus the movable terminal 9
And the load terminal 5 are electrically connected. Next, the operation of the present embodiment will be described. FIG. 1 shows a state in which the circuit opening / closing mechanism 6 is closed.
In this state, when an abnormality occurs, for example, when an overcurrent flows, the armature 34 is moved to the magnetic pole 2 by the attraction of the electromagnetic device 25.
7 is sucked. As a result, the distal end of the armature 34 presses the latch body 22 to rotate the latch body 22 counterclockwise about the support shaft 3. Therefore, the engagement portion 24 of the latch body 22 is disengaged from the pin 21 of the second link body 19. Thereby, the second link body 19 can be turned in the counterclockwise direction, and the opening / closing body 15 is moved by the upper surface of the first link body 14 by the elastic force of the elastic body 17.
Is pushed up while approaching the lower part of the second link body 19 side. In addition, the rotation of the first link body 14 causes the operation body 11 to rotate.
Rotates counterclockwise. At the same time, contact arm 8
Is allowed to rotate upward, and the circuit opening / closing mechanism 6 is opened. As described above, immediately after the control mechanism 13 is tripped by the detection operation of the electromagnetic device 25 and the circuit is cut off, the armature 34 is separated from the magnetic pole 27 by the urging force of the tension spring 38, and the latch body 22 It is pushed by the armature 34 and returns clockwise. Therefore, by tilting the operating tool 11 clockwise, the first link 1
4 descends while correcting the posture vertically. This lowering pushes the opening / closing body 15 and the contact arm 8 moves the opening / closing body 1.
5 to close the circuit opening / closing mechanism 6. At this time, the second link body 19 is
As a result, the pin 21 at the free end of rotation and the engaging portion 24 of the latch body 22 resiliently engage with each other. At the time of assembly, the frame 29 holding the magnetic core 26 and the like and the control mechanism 13 are assembled on the base 2. Before the cover 3 is fixed to the base 2, the frame 29
Armature 34 into Sekiguchi 30
A tension spring 38 is stretched in the small hole 37 of the sixth and the small hole 33 of the frame 29. At this time, since the tension spring 38 is along the armature 34, the mounting operation can be performed on the wide opening side of the base 2. Further, since one end of the latch body 22 is sandwiched by the rising pieces 36 in the process of inserting the armature 34 into the opening 30, the connection between the armature 34 and the latch body 22 can be easily performed. Further, the armature 34 is brought into contact with the frame 29 with the stopper 35 by the urging force of the tension spring 38, and is stabilized by being supported by the edge 32a of the bent piece 32. Further, the edge portion 31a of the support portion 31 and the edge portion 32a of the bent piece 32 located directly above the support portion 31 support the armature 34 in a line contact state. For this reason, the distance between the edge portions 32a, 32a is reduced so that the armature 34
Can be restricted, and the armature 34 can be smoothly rotated. As described above, the present invention employs a tension spring as a spring for urging the armature in a direction away from the magnetic pole, and this tension spring is provided between the frame and the rising piece of the armature. The following effects are obtained because the cable is stretched apart from the surface. (1) Unlike the prior art 1, the armature is not provided with a tilting force that causes the suction force to be lost. (2) Since the length of the tension spring can be made longer than that of the prior art 2, the spring constant can be reduced, and the armature is pulled by a required tension force in a normal state, and the armature is attracted to the magnetic pole by a relatively small force in an abnormal state. And act on the control mechanism. Therefore, it is possible to obtain a reliable circuit opening / closing operation without malfunction and at the time of abnormality. (3) The tension spring does not rub against the surface of the armature, and the operation is not destabilized by losing the suction force or destabilizing the spring force. (4) When assembling the tension spring, it is only necessary to lock the tension spring to the frame and the rising piece of the armature, so that workability is good.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional side view showing an embodiment of the present invention. FIG. 2 is an enlarged perspective view of the same main part. FIG. 3 is an enlarged cross-sectional view of the same main part. 1; FIG. 5 is an enlarged perspective view of a main part of the same; FIG. 6 is a perspective view showing a main part of a prior art 2;
... Control mechanism 25 ... Electromagnetic device 34 ... Armature 38 ... Tension spring

Claims (1)

(57) [Claims] An operating body; a circuit opening / closing mechanism having a movable contact and a swingable contact arm urged in a direction away from the fixed contact; a magnetic core having a magnetic pole at one end, and a winding for applying a magnetic flux to the magnetic core Wire, frame magnetically coupled to magnetic core,
An armature having a rising piece at the distal end and a base end rotatably held by the frame and arranged to face the magnetic pole; and An electromagnetic device having a tension spring for applying a spring force to separate the armature from the magnetic pole so that the armature is attracted to the magnetic pole and turned; and And a control mechanism for opening the circuit opening / closing mechanism by rotating the armature.