JP2001101962A - Circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit breaker for breaking short current that has small size and is not much affected by magnetic influence between abut poles. SOLUTION: The circuit breaker comprises a monopole breaking unit 10 including a fixed contactor 14 having a fixed contact 14a, a movable contactor 16 having a movable contact 16a opposing the fixed contact 14a, and a unit case 12 having a torsion spring for biasing the movable contact 16a to the fixed contact 14a, a device part 34 for switching the movable contactor 16, and a base 30 for containing the monopole breaking unit 10 and a device part 34. A U-shaped magnetic body 50 is located in exterior of the unit case 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker having a double case structure having an inner housing made of another insulating member inside a base.

[0002]

2. Description of the Related Art FIG.
FIG. 9 is a schematic exploded perspective view of a conventional circuit breaker disclosed in Japanese Patent Application Publication No. 9-No. In the drawing, reference numeral 1 denotes a single pole breaking unit, in which a fixed contact (not shown) and a movable contact (not shown) rotatably provided on a holder (not shown).
Having. Reference numeral 2 denotes a mechanism for rotating the movable contact, and reference numeral 3 denotes a communication rod for transmitting the operation of the mechanism 2 to the movable contact. Reference numeral 4 denotes a base for housing the single pole breaking unit 1, the mechanism 2, and a detection unit (not shown) for detecting an overcurrent connected to the single pole breaking unit 1, and a cover (not shown) includes a base. 4 screwed.

Next, the operation of a conventional circuit breaker will be described. Since the cutoff unit that cuts off the current inside is isolated for each single pole, the pressure generated inside the single pole cutoff unit 1 generated when cutting off an excessive current such as a short-circuit current is high. Since the arc is efficiently narrowed, a circuit breaker having a large breaking capacity can be obtained without increasing the size of the circuit breaker.

[0004]

In the conventional circuit breaker as described above, the breaking capacity can be increased with the same external dimensions, but a large current flows through the movable contact as the breaking capacity increases. Then, there is a problem that the magnetism generated by this current increases, that is, the magnetic flux density increases. For example, there is a problem that an increase in the magnetic flux density causes a malfunction of an electromagnetic trip device or the like that operates by an electromagnetic force outside the single-pole shutoff unit 1. Further, in the case of a multi-pole circuit breaker, the movable contact is attracted or repelled between adjacent poles, and the movable contact comes into contact with the inner wall of the case of the single-pole breaking unit 1 or the movable contact Is provided for each pole, and since the single-pole blocking unit 1 moves together with the holder, there is a problem that a strong strength is required for the side wall of the base 4 or an electric connection with the detection unit side. There was a problem that connection was difficult.

Further, since the pressure generated inside the single-pole breaking unit 1 is high, it is necessary to use a high-strength material for the case of the single-pole breaking unit 1 and make it thicker. There was a problem to do. Furthermore, since the movable contact repelled by the electromagnetic force collides with the inside of the case of the single-pole breaking unit 1, it is necessary to use a high-strength material for the case and make the case thicker, and the single-pole breaking unit becomes large. There was a problem.

As described above, a circuit breaker having a single pole breaking unit 1 uses substantially the same components as those of a so-called single case circuit breaker not having a single pole breaking unit 1. When this is done, the breaking capacity can be increased. In some cases, a magnetic material is used for a single-case circuit breaker, but the magnetic material is used for high-speed opening of a movable contact or induction of an arc.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a circuit breaker capable of shielding magnetism generated outside a unit case of a single pole breaking unit. It is another object of the present invention to provide a circuit breaker in which a unit case of a single-pole breaking unit can be made small.

[0008]

In a circuit breaker according to the present invention, a first contact having a first contact and a second contact having a second contact facing the first contact are provided. ,
A single pole breaking unit having a unit case accommodating a biasing means for biasing the second contact to the first contact, a mechanism for opening and closing the second contact, and the single pole breaking unit A circuit breaker comprising: a base accommodating the mechanism; and a magnetic body for shielding magnetism generated according to a breaking current at the time of breaking, outside the unit case.

The magnetic body has a U-shaped cross section. In addition, the magnetic body is formed by stacking a plurality of plate-shaped ones. The U-shaped bottom is provided in the direction in which the second contact of the unit case is separated. Further, a U-shaped bottom is provided between the rotation center of the second contact and the second contact.

[0010] Further, a concave portion formed in the unit case is formed so that both U-shaped legs are fitted into the concave portion. The magnetic body and the unit case have the same width. The U-shaped legs of the magnetic body sandwich the unit case. Further, a magnetic body is provided outside the unit case at a portion where the second contact rotates due to the electromagnetic repulsion and comes into contact with the inside of the unit case.

Further, a magnetic body is arranged between adjacent unit cases. Also, a circuit breaker accommodating a plurality of single pole breaking units side by side on a base, wherein the unit cases of the single pole breaking units at both ends are surrounded by a magnetic body having a U-shaped cross section. Furthermore, an overcurrent detection unit that is housed in the base, is electrically connected in series between the second contact and the external terminal, and detects an overcurrent of the electric circuit by magnetism is provided. A magnetic body is provided between the first and second parts.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is an exploded perspective view showing the configuration of the circuit breaker according to Embodiment 1 of the present invention. FIG. 2 is a side view showing a partial cross section of the circuit breaker of FIG. 1, and shows a state where the movable contact is in an ON state.
FIG. 3 is a perspective view showing a state where the movable contact of the single pole breaking unit of the circuit breaker shown in FIG. 1 is in a repulsive state. FIG. 4 is a perspective view for explaining the assembling of the single-pole breaking unit shown in FIG. 1, and illustration of internal components is omitted.

In FIGS. 1 to 4, reference numeral 10 denotes a single pole breaking unit, which is a unit case 1 made of an insulating resin material.
2. Fixed contact 14 (first contact) to which fixed contact 14a (first contact) is attached, movable contact 16 (second contact) to which movable contact 16a (second contact) is attached ),
Holder 18 formed of an insulating resin material that rotatably holds movable contact 16, intermediate connection conductor 2 having one end connected to movable contact 16 and the other end connected to detection unit 36.
2. It has an arc-extinguishing grid 24 and the like. The unit case 12 is formed by tightly joining the left case 12A and the right case 12B with screws or rivets (not shown) or the like, and the upper part of the arc-extinguishing grid 24 (see FIG. A collision portion 16b is provided at an upper portion (see FIG. 2) of an intermediate portion between the moving center and the movable contact 16a. 19
Reference numeral denotes a torsion spring for urging the movable contact 16 in the clockwise direction in FIG. 2, and the movable contact 16a receives an urging force from the fixed contact 14a when the movable contact 16 is in the ON state.

Reference numeral 20 denotes a connecting rod penetrating through the holder 18 of each pole and cooperating with a toggle link mechanism (not numbered) of the mechanism section 34. 30 is a unipolar cutoff unit 1
0, a base in which the mechanism unit 34 and the detection unit 36 are housed. The single-pole unit 10 is housed in the base 30 in a state where the three-pole unit is integrated via a spacer (not shown). Note that a configuration may be employed in which the single pole cutoff units 10 are closely attached to each other without a spacer. 32 is a cover, and the base 3
Screwed to zero. Reference numeral 36 denotes a detection unit having an overcurrent trip device and the like inside the unit case 38, and reference numeral 40 denotes a terminal that is electrically connected to the intermediate connection conductor 22 and connects an electric wire (not shown) to the outside of the main body. 50 is U
FIG. 3 is a U-shaped magnetic body formed of a steel plate bent into a U-shape, and is composed of a leg 50b and a connecting portion 50a.
Are arranged in the unit case 12 from the direction of arrow A shown in FIG. The U-shaped magnetic body 50 is provided with all the unipolar cutoff units 1
0, that is, at the installation pole of the mechanism section 2 and other poles.

In the circuit breaker configured as described above, since the U-shaped magnetic body 50, which is a magnetic body, is provided outside the unit case 12, magnetism generated outside the unit case 12 can be shielded. Therefore, it is possible to prevent the electromagnetic trip device or the like operated by the electromagnetic force from malfunctioning. Further, since the unit case 12 is formed of an insulating material, it is not necessary to insulate the U-shaped magnetic body 50. In the case of a multi-pole circuit breaker, the U-shaped magnetic body 5
Since the zero leg portion 50b is disposed between the poles, deformation of the movable contact 16 due to a large current, suction and repulsion of the movable contact with an adjacent pole, and movement of the single-pole blocking unit 1 together with the holder. And the size of the base 30 can be reduced, or it can be electrically connected easily to the detection unit 36 from the viewpoint of mechanical strength against movement of the connection portion.

The U-shaped magnetic body 50 is a magnetic body having a U-shaped cross section, and the leg 50b sandwiches the unit case 12, thereby contributing to the reinforcement of the unit case 12.
For example, the thermal energy of the arc generated at the time of current interruption melts the insulator, for example, the unit case 12, inside the single-pole breaking unit 10, and the internal pressure of the single-pole breaking unit 10 rises sharply. Since the U-shaped magnetic body 50 can receive the single-pole cutoff unit 10
Can be prevented from being destroyed. In particular, the U-shaped magnetic body 5
0 leg 50b is the right case 12A of the unit case 12.
And the left case 12B.
Riveting, screwing, and the like, which are necessary for fixing the A and 12B, can be reduced, or a predetermined fixing force can be obtained without requiring other fixing means.

Further, the connecting portion 50a of the U-shaped magnetic body 50
Is provided in the rotating direction of the movable contact 16 (in the direction of the upper surface of the unit case 12 in FIG. 2), an excessive current such as a short-circuit current flows through the circuit breaker, and the fixed contact 14
And the electromagnetic repulsive force caused by the excessive current flowing through the movable contact 16, the movable contact 16 rotates in a direction away from the fixed contact 14, and the connecting portion 50 a receives an impact force when the movable contact 16 collides with the collision portion 12 b. In addition, the size and destruction of the unit case 12 can be prevented. Particularly, as in the first embodiment, the connecting portion 50a of the U-shaped magnetic body 50 is provided between the rotation center of the movable contact 16 and the movable contact 16a in the rotating direction of the movable contact 16. As a result, the impact force can be more effectively received.

Further, the connecting portion 50a of the U-shaped magnetic body 50
Are provided in the direction of rotation of the movable contact 16, and the legs 50b extend downward from the upper surface in FIG. 2, so that the repulsive magnetism can be strengthened and the movable contact 16 can be opened at a high speed. The maximum current when the short circuit is interrupted is determined by the two contacts 14a,
Since it occurs not during the contact of the movable contact 16a but during the rotation of the movable contact 16, it is more useful than when the connecting portion 50a is provided in the counter-rotating direction of the movable contact 16.

Here, the thickness of the U-shaped magnetic body 50 is 1 mm or more, preferably 2 mm or more from the viewpoint of magnetic shielding, reinforcement against the pressure resistance of the unit case 12, and reinforcement against the collision of the movable contact 16. Also, from the viewpoint of magnetic shielding, it is satisfactory if the thickness and area can almost shield the magnetic flux generated when the maximum rated current is interrupted,
In order to achieve the above-mentioned effect, it is sufficient that the thickness and the area are such that the magnetic flux generated when a half of the maximum rated current is cut off can be almost shielded.

Although the circuit breaker having the three-pole single-pole breaking unit 10 has been described, a circuit breaker other than three-pole, for example, a single-pole, two-pole, or four-pole circuit breaker may be used. Also, the case where the first contact (fixed contact 14a) is fixed has been described, but the first contact may also be a movable double repulsion type single pole breaking unit. In addition, a single-pole single-pole cutoff unit 10 having a pair of contacts 14 and 16
However, a two-point single-pole cutoff unit as disclosed in JP-A-5-217489 may be used. However, in the case of the single-pole single-pole breaking unit 10 shown in the first embodiment, the movable contact 16 for breaking the same short-circuit current is compared with the two-point single-pole breaking unit.
Since the impact force on the collision portion 12b is large, the U-shaped magnetic body 50 is more useful. In the case of the single-pole cutoff unit 10, the collision portion 12b is provided at the center of the upper surface of the unit case 12 in FIG. 2, so that the U-shaped magnetic body 50 can be sandwiched at the center of the unit case 12. Good tightening balance.

Embodiment 2 FIG. FIG. 5 is a side view showing a cross section of a part of the single pole breaking unit of the circuit breaker according to Embodiment 2 of the present invention, and FIG. 6 is a cross sectional view taken along the line VI-VI of FIG. 5 and 6, reference numeral 12d denotes a concave portion on the outer peripheral portion of the unit case 12, into which the leg portion 50b of the U-shaped magnetic body 50 fits.
2 and the U-shaped magnetic body 50 have substantially the same width. Reference numeral 62 denotes a voltage trip device that trips the circuit breaker with an external signal, and is disposed above the single-pole breaking unit 10 via a cover 60 formed of an insulating material. 64 is a plunger of the voltage trip device 62, which protrudes by an external signal,
The trip bar 66 of the mechanism 34 is rotated to open the movable contact 16. The other configuration is the same as that of the first embodiment, and a description thereof will be omitted.

With the above configuration, there is a device having a magnetic circuit relatively close to the conductive portion of the circuit breaker, such as a voltage trip device that is an accessory device of the circuit breaker. However, since the connecting portion 50b of the U-shaped magnetic body 50 is disposed between the unipolar cutoff unit 10 and the voltage trip device 62 having a magnetic circuit, the magnetic tripping effect of the connecting portion 50b causes the voltage trip device to drop. 1
The malfunction of the magnetic circuit device as in No. 3 can be prevented. The same effect can be obtained by disposing a magnetic shield made of a magnetic material around a magnetic circuit device such as the voltage trip device 13 instead of the U-shaped magnetic material 50.

As shown in FIG. 6, the movable contact 16
Operates in the direction of the arrow due to the electromagnetic repulsion caused by the large current generated between the fixed contact 14 and the fixed contact 14, but if the U-shaped magnetic body 50 is installed, the magnetic flux of the current flowing through the movable contact 16 is strengthened. Since the opening speed can be improved, excellent current limiting performance can be obtained. Further, since the leg portion 50b of the U-shaped magnetic body 50 is fitted into the concave portion 12d on the outer peripheral portion of the unit case 12, the assembling is easy and the assembling accuracy is high. Further, since the unit case 12 and the U-shaped magnetic body 50 have substantially the same width, it is easy to unitize the single-pole breaker unit 10, and the single-pole breaker is excellent in compatibility between the single-pole breaker and the multipole breaker. A unit 10 can be provided.

Embodiment 3 FIG. FIG. 7 is a side view showing a unipolar cutoff unit according to Embodiment 3 of the present invention, and FIG. 8 is a sectional view taken along line VIII-VIII in FIG.

In FIGS. 7 and 8, reference numeral 52 denotes a U-shaped magnetic body having legs 52b, which is disposed at a position surrounding the fixed contact 14. The other configuration is the same as that of the above-described embodiment, and a description thereof will be omitted. With this arrangement, the U-shaped magnetic body 52 can receive the internal pressure when a large current is interrupted, thereby preventing the unipolar interrupting unit 10 from being broken. Since the U-shaped magnetic body 52 is arranged, there is no need to insulate the U-shaped magnetic body 52, and in the case of a multi-pole circuit breaker, the legs 52b of the U-shaped magnetic body 52 are arranged between the poles. Therefore, the effect of shielding the magnetic flux of the other pole can be obtained by the leg portion 52b.

Further, when a large current is interrupted, the magnetic flux of the current flowing through the fixed contact 14 is strengthened and an electromagnetic force for opening the movable contact 16 is generated, so that the opening speed is improved and excellent current limiting performance is achieved. Obtainable.

As shown in FIGS. 7 and 8, if the leg portion 52b of the U-shaped magnetic body 52 is extended to a position surrounding the terminal portion 14b connected to the electric wire of the fixed contact 14, the multipole circuit can be interrupted. In the case of a container, the inter-electromagnetic force applied to the electric wire connected to the terminal portion 14b or the external force when the electric wire is tightened to the terminal portion 21 causes the terminal portion 2
1 can be prevented from being destroyed.

Embodiment 4 FIG. 9 is a side view showing a partial cross section of the unipolar cutoff unit according to Embodiment 4 of the present invention, and FIG. 10 is a cross sectional view taken along line XX of FIG.

9 and 10, reference numeral 54 denotes a leg 54b.
And is arranged at a position surrounding the grid 24. The other configuration is the same as that of the above-described embodiment, and a description thereof will be omitted. With such an arrangement, the U-shaped magnetic body 54 can receive the internal pressure when a large current is interrupted, so that the destruction of the unipolar interrupting unit 10 can be prevented. Since the U-shaped magnetic body 54 is arranged, there is no need to insulate the U-shaped magnetic body 54. In the case of a multi-pole circuit breaker, the legs 54b of the U-shaped magnetic body 54 are arranged between the poles. Therefore, an effect of shielding the magnetic flux of the other pole can be obtained by the leg portion 54b.

Further, by disposing the U-shaped magnetic body 54,
At the time of current interruption, the electromagnetic force that guides the arc generated between the fixed contact 14 and the movable contact 16 to the grid 24 can be enhanced, and the arc traveling performance can be improved.

Embodiment 5 FIG. 11 is a side view showing a partial cross section of the unipolar cutoff unit according to Embodiment 5 of the present invention, and FIG. 12 is a cross sectional view taken along line XII-XII in FIG.

11 and 12, reference numeral 56 denotes a U-shaped magnetic body having a connecting portion 56a and a leg portion 56b, and is disposed at a position surrounding the intermediate conductor 22. Reference numeral 15 denotes an axis serving as a center of rotation of the movable contact 16, and reference numeral 17 denotes a coil spring that biases the intermediate connection conductor 22 toward the movable contact 16. The other configuration is the same as that of the above-described embodiment, and a description thereof will be omitted. With this arrangement, the U-shaped magnetic body 56 can receive the internal pressure when a large current is interrupted, so that the single-pole shut-off unit 10 can be prevented from being broken. Since the U-shaped magnetic body 24 is arranged, there is no need to insulate the U-shaped magnetic body 56,
In the case of a multipole circuit breaker, the legs 5 of the U-shaped magnetic body 56
Since the poles 6b are arranged between the poles, an effect of shielding the magnetic flux of the other pole can be obtained by the legs 56b.

The connecting portion 56a of the U-shaped magnetic body 56
However, the magnetic flux from the unipolar cutoff unit 10 can be shielded from the overcurrent trip device built in the detection unit 36 connected to the intermediate conductor 22.

Embodiment 6 FIG. FIG. 13 is a partial side view showing a single-pole breaker unit according to Embodiment 6 of the present invention, and FIG. 14 is a cross-sectional view of the multipole breaker along line IXV-IXV in FIG.

In FIGS. 13 and 14, reference numeral 60 denotes a U-shaped magnetic body having a connecting portion 60a and a leg portion 60b, and is located at a position surrounding the outermost of a plurality of single-pole breaking units 10 constituting a multi-pole breaker. Are located. The other configuration is the same as that of the above-described embodiment, and a description thereof will be omitted. With this arrangement, the U-shaped magnetic body 26 is arranged on the outer peripheral portion of the single-pole cutoff unit 10, so that the U-shaped magnetic body 6
0 does not need to be insulated and the legs 60 of the U-shaped magnetic body 60
Since b is disposed on the side surface of the outermost single-pole breaking unit 10, this leg portion 60b obtains a magnetic shielding effect for preventing a malfunction when another circuit breaker is installed relatively close. Can be.

Further, since the U-shaped magnetic body 60 integrates multiple poles, it is easy to disperse the force applied to the base 30, so that the electromagnetic force between the poles applied to the electric wire connected to the terminal portion 14b and the electric wire can be reduced. Due to the external force when tightening to the terminal part 14b,
The base 30 can be prevented from being broken.

Embodiment 7 FIG. 15 is a perspective view showing a detection unit according to Embodiment 7 of the present invention. FIG.
5, reference numeral 41 denotes the detection unit 36 and the unipolar cutoff unit 10
62 is a U-shaped magnetic body having a connecting portion 62a and a leg portion 62b,
It is arranged at a position surrounding the detection unit 36 and opposed to the unipolar cutoff unit 10. The other configuration is the same as that of the above-described embodiment, and a description thereof will be omitted.

As described above, since the U-shaped magnetic body 62 is arranged on the outer periphery of the detection unit 36, the U-shaped magnetic body 6
2 need not be insulated, and the leg 62 of the U-shaped magnetic body 62
With b, a magnetic shielding effect for preventing a malfunction when another circuit breaker is installed relatively close can be obtained. Further, the connecting portion 62a of the U-shaped magnetic body 62 can magnetically shield the magnetic flux from the unipolar cutoff unit 10 and prevent malfunction of the overcurrent tripping device built in the detection unit 36. it can.

In the case of a multi-pole circuit breaker, the detecting unit 36 is driven by an interelectrode electromagnetic force applied to the electric wire connected to the terminal portion 40 and an external force when the electric wire is tightened to the terminal portion 40.
Can be prevented from destruction of the portion in contact with the terminal portion 40.

Embodiment 8 FIG. FIG. 16 is a top view showing a square-shaped magnetic body according to Embodiment 8 of the present invention, and FIG. 17 is a side view showing a unipolar cutoff unit.

In FIGS. 16 and 17, reference numeral 64 denotes a square-shaped magnetic body, which is installed at a position surrounding the outer peripheral portion of the single-pole breaking unit 10. The other configuration is the same as that of the above-described embodiment, and a description thereof will be omitted. With this arrangement, not only the mechanical strength is increased but also the effects of the fifth and sixth embodiments can be expected as compared with the case where a U-shaped magnetic body is used. Note that the U-shaped magnetic body can be combined with each other in the case of the U-shaped magnetic body described in the above-described embodiment, and the effect of improving the strength can be obtained.

Embodiment 9 FIG. FIG. 18 is a perspective view showing a single pole cutoff unit according to Embodiment 9 of the present invention.

In FIG. 18, reference numeral 66 denotes a flat plate-shaped magnetic body, in which a concave portion 12c provided on the side surface of the unit case 12 of the unipolar cutoff unit 10 is provided. The other configuration is the same as that of the above-described embodiment, and a description thereof will be omitted. Thus, the concave portion 1 on the outer peripheral portion of the unit case 12
Since the plate-shaped magnetic body 66 is arranged in 2c, there is no need to insulate the plate-shaped magnetic body 32, and the effect of shielding the magnetic flux of the other pole can be obtained. Further, since the plate-shaped magnetic body 32 is provided substantially at the center of the side surface of the unit case 12, in other words, substantially coincident with the rotation locus of the movable contact 16, the magnetic shielding efficiency is extremely high.

Embodiment 10 FIG. FIG. 19 is a perspective view showing a unipolar cutoff unit according to Embodiment 10 of the present invention.

In FIG. 19, reference numeral 68 denotes a plurality of magnetic members 6
8a, which is provided on the outer peripheral portion of the single pole cutoff unit 10. The other configuration is the same as that of the above-described embodiment, and a description thereof will be omitted. As described above, since the magnetic body 68a is formed by lamination, the influence of the eddy current can be reduced, and the effect of controlling the magnetic flux of the magnetic body as described above can be improved as compared with the integrated magnetic body. .

[0046]

In the circuit breaker according to the present invention,
A first contact having a first contact, a second contact having a second contact facing the first contact, and a bias for biasing the second contact to the first contact A circuit breaker comprising: a single-pole breaking unit having a unit case for housing the means; a mechanism for opening and closing the second contact; and a base for housing the single-pole breaking unit and the mechanism. Since the magnetic body that shields the magnetism generated in response to the breaking current at the time of breaking is provided outside the unit case, the magnetism generated outside the unit case of the single pole breaking unit can be blocked.

Since the magnetic body has a U-shaped cross section,
A magnetic body is arranged between the poles of the single-pole breaking unit, and the movable contact deforms due to a large current, attracts or repels the movable contact with an adjacent pole, or the single-pole breaking unit 1 moves together with the holder. Can be reduced.

Further, since a plurality of plate-like magnetic materials are stacked, the influence of eddy current can be reduced and the magnetic shielding is excellent.

Further, since the U-shaped bottom is provided in the direction in which the second contact of the unit case is separated, the movable contact 16 is moved at a high speed when the movable contact is separated from the fixed contact by the electromagnetic repulsive force. Can be opened.

Further, since the U-shaped bottom is provided between the rotation center of the second contact and the second contact, the movable contact moves away from the fixed contact by the electromagnetic repulsion. Since the bottom part receives a part of the impact force when it rotates and collides with the collision part of the unit case, the unit case can be reduced in size and prevented from being broken.

Further, since the U-shaped legs are formed so as to fit into the recess formed in the unit case and the recess, the assembling is easy and the assembling accuracy is high.

Further, since the magnetic body and the unit case have the same width, it is easy to unitize and the compatibility between the single pole breaker and the multi pole breaker is excellent.

Further, since the U-shaped legs of the magnetic material sandwich the unit case, the unit case is mechanically reinforced, which contributes to downsizing of the unit case.

Also, since the second contact is rotated by electromagnetic repulsion and a magnetic body is provided outside the unit case at a portion which comes into contact with the inside of the unit case, the movable contact separates from the fixed contact due to the electromagnetic repulsive force. Since the bottom part receives the impact force when it rotates in the direction and collides with the collision part of the unit case, the unit case can be reduced in size and prevented from being broken.

Further, since the magnetic material is arranged between adjacent unit cases, deformation of the movable contact caused by a large current, suction and repulsion of the movable contact with the adjacent pole, or a single pole breaking unit together with the holder. 1 can be reduced from moving.

Also, a circuit breaker accommodating a plurality of single pole breaking units side by side on a base, wherein the unit cases of the single pole breaking units at both ends are surrounded by a magnetic material having a U-shaped cross section. The base can be prevented from breaking.

Further, an overcurrent detecting portion is provided in the base, electrically connected in series between the second contact and the external terminal, and detects an overcurrent of the electric circuit by magnetism. Since a magnetic body is provided between the overcurrent detection unit and the overcurrent detection unit, the influence of the magnetism of the overcurrent detection unit can be reduced.

[Brief description of the drawings]

FIG. 1 is a fragmentary side view showing a circuit breaker according to Embodiment 1 of the present invention, showing a state where the circuit breaker is in an ON state.

FIG. 2 is a perspective view showing a single-pole breaking unit of the circuit breaker shown in FIG. 1 when the movable contact is in a repulsive state.

FIG. 3 is an exploded perspective view showing a configuration of the circuit breaker shown in FIG.

FIG. 4 is a perspective view illustrating the assembling of the unipolar cutoff unit shown in FIG. 1;

FIG. 5 is a partial side view showing a single pole breaking unit of the circuit breaker according to Embodiment 2 of the present invention.

FIG. 6 is a sectional view taken along line VV in FIG. 5;

FIG. 7 is a partial side view showing a single pole cutoff unit according to Embodiment 3 of the present invention.

FIG. 8 is a sectional view taken along lines VIII-VIII in FIG. 7;

FIG. 9 is a partial side view showing a single pole cutoff unit according to Embodiment 4 of the present invention.

FIG. 10 is a sectional view taken along line XX in FIG. 9;

FIG. 11 is a partial side view showing a unipolar cutoff unit according to Embodiment 5 of the present invention.

FIG. 12 is a sectional view taken along lines XII-XII in FIG. 11;

FIG. 13 is a partial side view showing a single pole cutoff unit according to Embodiment 6 of the present invention.

FIG. 14 is a cross-sectional view of the multi-pole circuit breaker along line IXV-IXV.

FIG. 15 is a perspective view showing a detection unit according to Embodiment 7 of the present invention.

FIG. 16 is a top view showing a square-shaped magnetic body according to Embodiment 8 of the present invention.

FIG. 17 is a partial side view showing a single pole cutoff unit according to Embodiment 8 of the present invention.

FIG. 18 is a perspective view showing a single pole cutoff unit according to Embodiment 9 of the present invention.

FIG. 19 is a perspective view showing a unipolar cutoff unit according to Embodiment 10 of the present invention.

FIG. 20 is a schematic exploded perspective view of a conventional circuit breaker.

[Explanation of symbols]

10 single pole shut-off unit, 12 unit case,
12d recess, 14 fixed contact, 16 movable contact, 19 torsion spring, 20 connecting rod,
30 base, 32 cover, 34 mechanism,
36 detection units, 40 terminals, 50, 5
2, 54, 56, 60, 62 U-shaped connecting conductor, 5
0a joint, 50b leg, 64 square magnetic material

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takao Mitsuhashi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Mitsuru Month 2-3-2 Marunouchi, Chiyoda-ku, Tokyo 3 F term in Ryo Denki Co., Ltd. (reference) 5G030 AA01 BA02 BA05 DE01 FA02 FC04 XX08

Claims (12)

[Claims] A first contact having a first contact, a second contact having a second contact opposing the first contact,
A single pole breaking unit having a unit case accommodating a biasing means for biasing the second contact to the first contact, a mechanism for opening and closing the second contact, and the single pole breaking unit A circuit breaker comprising: a base accommodating the mechanism unit; and a magnetic body for shielding magnetism generated according to a breaking current at the time of breaking, outside the unit case. . 2. The circuit breaker according to claim 1, wherein the magnetic body has a U-shaped cross section. 3. The circuit breaker according to claim 2, wherein a plurality of plate-like magnetic bodies are stacked. 4. The U-shaped bottom is the second part of the unit case.
3. The circuit breaker according to claim 2, wherein the contact is provided in a direction in which the contacts are separated. 5. The circuit breaker according to claim 4, wherein the U-shaped bottom is provided between the center of rotation of the second contact and the second contact. 6. The circuit breaker according to claim 2, wherein a concave portion formed in the unit case is formed so that both U-shaped legs fit into the concave portion. 7. The circuit breaker according to claim 2, wherein the magnetic body and the unit case have the same width. 8. The circuit breaker according to claim 2, wherein the U-shaped legs of the magnetic material sandwich the unit case. 9. The circuit breaker according to claim 8, wherein a magnetic body is provided outside the unit case at a portion where the second contact rotates by electromagnetic repulsion and abuts on the inside of the unit case. 10. The circuit breaker according to claim 1, wherein a magnetic body is disposed between adjacent unit cases. 11. A circuit breaker for accommodating a plurality of single pole cutoff units side by side on a base, wherein unit cases of the single pole cutoff units at both ends are surrounded by a magnetic material having a U-shaped cross section. The circuit breaker according to claim 1, wherein 12. An overcurrent detection unit which is housed in a base, is electrically connected in series between the second contact and an external terminal, and detects an overcurrent of an electric circuit by magnetism. 2. The circuit breaker according to claim 1, wherein a magnetic body is provided between the circuit breaker and the current detector.