JPH09204868A - Breaker trip device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent partial saturation of a yoke even if excess current flows in a breaker, prevent drop in attraction force to a movable iron core, and surely break an electric circuit by thickening the bottom part section of a U-shaped yoke than the side part section. SOLUTION: For example, when the bottom part cross section of a U-shaped yoke is intended to make two times the two side part cross sections, a part corresponding to the side part of a plate body equivalent to two times thickness is cut or forged to form the same shape, and the thin part is bent in a U shape to form a yoke. The partial saturation of the yoke 3 is not produced, the magnetic efficiency of a magnetic circuit comprising the yoke 3 and a movable iron core 2 is not decreased, the attraction force to the movable iron core is not also decreased. Even if excess current in a relatively large region flows, the movable iron core 2 is attracted to the yoke and an electric circuit can be broken.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker tripping device for operating a breaker by detecting an overcurrent in a relatively large area.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIGS. FIG. 8 is a cross-sectional view of the breaker trip device.
FIG. 9 is a sectional view of the yoke. FIG. 10 is a perspective view of the yoke. FIG. 11 is a cross-sectional view for explaining the saturation of the yoke.

As shown in FIG. 8, the breaker tripping device includes a bimetal 1 corresponding to an electric path, a movable iron piece 2, a yoke 3, and a return spring 4.

The movable iron core 2 is a magnetic strip-shaped body having shaft portions 5 on both sides and a lock receiving portion 6 for tripping.
And a bimetal interlocking section 7.

The bimetal 1 is a direct heat type bimetal for detecting an overcurrent. The bimetal 1 is disposed to face the movable iron piece 2 and engages with the bimetal interlocking portion 7. When an overcurrent flows, the movable iron piece is bent by heat generation. 2 is driven against the spring force of the return spring 4. The upper end of the bimetal 1 is fixedly connected to the load terminal 8 a as a fixed portion and is electrically and mechanically connected. The lower end of the bimetal 1 is used as an operating portion to lock the bimetal interlocking portion 7 and to be connected to the lead wire 9. .

As shown in FIG. 9, the yoke 3 has a substantially U-shaped cross section, and the bimetal 1 penetrating inward.
And a side surface 3b, 3c extending from both ends of the bottom surface 3a. The bottom surface 3a and the side surfaces 3b and 3c have substantially the same thickness. The yoke 3 is for detecting overcurrent in a relatively large area. When the overcurrent in a relatively large area flows through the bimetal 1, the return spring 4 is used.
Is a magnetic material that attracts the movable iron piece 2 against the spring force of the magnetic iron.

[0007] The return spring 4 is driven by the spring force to move the movable iron piece 2.
To return in a direction away from the bimetal 1.

Reference numerals 8a and 8b denote load terminals and reference numeral 10 denotes a cradle serving as a latch link to be locked in the locking receiving portion.

The lead wire 9 and the load terminal 8 which are electric paths
When an overcurrent flows through the bimetal 1 through the a and 8b, the bimetal 1 gradually bends in the direction of arrow A, and the movable iron piece 2 is pressed against the bimetal 1 at the bimetal interlocking portion 7. And the movable iron piece 2 rotates counterclockwise B direction against the spring force of the return spring 4 about the shaft portion 5 as an axis,
The cradle 10 is removed from the lock receiving portion 6. When the movable iron piece 2 is tripped and the cradle 10 is tripped, the cradle 10 rotates counterclockwise, and the reversing spring 1
Since 1 is inverted to open the movable contact 12, the electric circuit is cut off.

On the other hand, when an overcurrent in a relatively large area flows in the electric path, as shown in FIG. 9, the magnetic flux generated around the bimetal 1 by the current flowing in the bimetal 1 causes a gap between the yoke 3 and the movable iron piece 2 and the gap between them. It flows through the magnetic path C including the portion G. Then, the movable iron piece 2 is instantly sucked into the yoke 3 faster than the bending operation of the bimetal 1 so that the gap G becomes smaller. Due to the suction, the movable iron piece 2 rotates counterclockwise in the direction B around the shaft 5, and the cradle 10 locked on the movable iron piece 2 is pulled off. Then, the movable iron piece 2 is tripped to operate the cradle 10.
When the cradle 10 is tripped, the cradle 10 rotates counterclockwise, and the reversing spring 11 reverses to drive the movable contact 12 so that the electric path is cut off.

[0011]

By the way, in general, the breaker sets the instantaneous touching current to several times the rated current.
When an excessive current such as an instantaneous moving current flows, the magnetic flux density of the substantially U-shaped yoke 3 shifts from a linear region to a saturated region.

However, in the substantially U-shaped yoke 3 shown in FIG. 10, since a large amount of magnetic flux passes through the bottom surface portion 3a which is the cross section E of the yoke 3, as shown by the hatched portion in FIG. Saturation begins. Then, partial saturation occurs in the substantially U-shaped yoke 3 to increase the magnetic resistance, and it becomes difficult for the magnetic flux to pass through the gap G. Therefore, there is a problem that the magnetic efficiency of the magnetic path formed by the yoke 3 and the movable iron core 2 deteriorates, and the attraction force to the movable iron core 2 decreases.

The present invention has been made in order to solve the above problems, and the yoke is not partially saturated even if an excessive current flows through the breaker, and the attraction force to the movable iron core does not decrease, so that the breaker can be securely operated. Another object of the present invention is to provide a tripping device for a breaker that cuts off an electric circuit.

[0014]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides the invention as set forth in claim 1, in which the electric path and the bottom surface portion extend from both ends of the bottom surface portion and face each other. A U-shaped yoke having a side surface portion and surrounding the electric path by the bottom surface portion and the side surface portion, and a tip facing the end portion of the side surface portion of the yoke, which is attracted by the yoke excited when an overcurrent flows through the electric path to form the electric path. In a device for tripping a breaker having a movable iron piece for blocking, a cross section of a bottom surface portion of the U-shaped yoke is thicker than a cross section of a side surface portion.

According to a second aspect of the invention, an electric circuit,
A U-shaped yoke having a bottom surface portion and side surface portions extending from both ends of the bottom surface portion and facing each other and enclosing the electric path by the bottom surface portion and the side surface portion, and facing the tip of the side surface portion of the yoke and passing through the electric path. In a tripping device of a breaker having a movable iron piece that is attracted to a yoke excited when a current flows and interrupts an electric path, a plate-shaped ferromagnetic piece is provided on an inner surface of a bottom portion of the yoke, and a bottom surface of the yoke is provided. It is characterized in that the total cross section including the cross section of the portion and the cross section of the ferromagnetic piece is made thicker than the cross section of the side surface portion.

According to the invention of claim 3, an electric circuit and
A U-shaped yoke having a bottom surface portion and side surface portions extending from both ends of the bottom surface portion and facing each other and enclosing the electric path by the bottom surface portion and the side surface portion, and facing the tip of the side surface portion of the yoke and passing through the electric path. In a trip device for a breaker, which has a movable iron piece that is attracted by a magnetized yoke when a current flows and interrupts an electric path, the yoke has two L-shaped L-shaped members each having a substantially uniform thickness. It is characterized in that one surface of each of the U-shaped ferromagnetic pieces is overlapped with each other and the other surfaces thereof are opposed to each other to form a U-shape.

According to a fourth aspect of the invention, an electric circuit and
A U-shaped yoke having a bottom surface portion and side surface portions extending from both ends of the bottom surface portion and facing each other and enclosing the electric path by the bottom surface portion and the side surface portion, and facing the tip of the side surface portion of the yoke and passing through the electric path. In a tripping device of a breaker having a movable iron piece that is attracted by a magnetized yoke when a current flows and cuts off an electric path, a side surface tip is narrowed to reduce a tip surface facing the movable iron piece. It is what

According to a fifth aspect of the invention, a through hole is provided in the bottom surface of the yoke and the body of the breaker, a screw hole is provided in the ferromagnetic piece, and a screw of the ferromagnetic material is provided in the body of the breaker. It is characterized in that it is inserted into the through hole and the through hole of the bottom surface of the yoke and screwed with the ferromagnetic piece.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of a trip device for a breaker according to the present invention will be described with reference to FIGS. 1 to 3, a second embodiment will be described with reference to FIG. 4, and a third embodiment will be described. The fourth embodiment will be described with reference to FIG. 5, based on FIG. 6, and the fifth embodiment will be described with reference to FIG.

[First Embodiment] FIG. 1 is a sectional view of a tripping device of a breaker. FIG. 2 is a perspective view of the yoke.
FIG. 3 is an explanatory diagram of a method for manufacturing a yoke. In FIG. 1, the same parts as those of the breaker trip device described in the above-mentioned conventional technique are designated by the same reference numerals, and detailed description of the same parts will be omitted.

The breaker trip device of the first embodiment shown in FIG. 1 is different from the breaker trip device described in the above-mentioned prior art in that it has the following features.

That is, as shown in FIG. 2, the cross-sectional area of the cross-section D of the bottom surface portion 3a of the yoke 3 is approximately twice the cross-sectional area of the cross-section E of the bottom surface portion 3a of the yoke 3 described in the prior art. Is. For example, as shown in FIG. 3, the yoke 3 has a cross-sectional area of a cross section E of the bottom surface portion 3a of the yoke 3 described in the related art.
The side portion indicated by diagonal lines is cut or forged from the plate body which is approximately twice the size of the above to form the same shape, and the thinned portion is bent and formed.

Since the cross-sectional area of the cross section D of the bottom surface portion 3a is doubled, partial saturation of the yoke 3 does not occur. Therefore, the magnetic efficiency of the magnetic path formed by the yoke 3 and the movable iron core 2 does not decrease, and the attraction force to the movable iron core 2 does not decrease.
Therefore, when an overcurrent in a relatively large area flows,
The movable iron core 2 is attracted to the yoke 3 and the electric path is cut off.

[Second Embodiment] FIG. 4 is a perspective view of a yoke. In the second embodiment, detailed description of the same parts as those of the breaker trip device described in the above-mentioned conventional technique will be omitted.

The breaker tripping device of the second embodiment is different from the breaker tripping device described in the above-mentioned prior art in that it has the following features.

That is, as shown in FIG. 4, the ferromagnetic piece 13 is provided on the bottom surface 3a of the yoke 3 by means such as caulking or welding.

The cross section F of the ferromagnetic piece 13 has substantially the same area as the cross section E of the bottom surface portion 3a of the yoke 3 having a substantially U-shape. Therefore, the total cross-sectional area of the ferromagnetic piece 13 and the bottom surface portion 3a of the yoke 3 is approximately twice the cross-sectional area of the cross-section E of the bottom surface portion 3a.

Since the total cross-sectional area is twice as large as the cross-sectional area of the cross section E of the bottom surface portion 3a, partial saturation of the yoke 3 does not occur. Therefore, the magnetic efficiency of the magnetic path formed by the yoke 3 and the movable iron core 2 does not decrease, and the attraction force to the movable iron core 2 does not decrease. Therefore, when an overcurrent flows in a relatively large area, the movable core 2 is attracted to the yoke 3,
The circuit is cut off.

Further, since the ferromagnetic piece 13 is provided on the yoke 3, it is possible to use the conventionally manufactured yoke as it is and prevent the reduction of the attraction force.

[Third Embodiment] FIG. 5 is a perspective view of a yoke. In the third embodiment, detailed description of the same parts as those of the breaker trip device described in the above-mentioned conventional technique will be omitted.

The breaker tripping device of the third embodiment is different from the breaker tripping device described in the above-mentioned prior art in that it has the following features.

That is, as shown in FIG.
L-shaped ferromagnetic material pieces 14a, 1 of the same shape bent into a letter shape
One side of 4b is superposed, the other side is opposed to each other to form a U-shape, and the superposed sides are fixed to form the yoke 14.

Cross sections G of the L-shaped ferromagnetic pieces 14a, 14b,
H is the bottom surface portion 3a of the yoke 3 as described in the related art.
The cross-sectional area is substantially the same as the cross-sectional area of the cross-section E. Therefore, the cross-sectional area of the bottom surface portion 14c of the yoke 14 formed by stacking the L-shaped ferromagnetic material pieces 14a and 14b is approximately twice the cross-sectional area of the bottom surface portion 3a of the yoke 3.

Since the cross-sectional area of the bottom surface portion 14c is twice as large as the cross-sectional area of the bottom surface portion 3a of the conventional yoke 3, partial saturation of the yoke 14 does not occur. Therefore, the magnetic efficiency of the magnetic path formed by the yoke 14 and the movable iron core 2 does not decrease, and the attraction force to the movable iron core 2 does not decrease. Therefore,
When an overcurrent flows in a relatively large area, the movable iron core 2 is attracted to the yoke 3 and the electric path is cut off.

Further, the cross-sectional area of the bottom surface portion 14c is approximately twice as large as the cross-sectional area of the bottom surface portion of the conventional yoke by using the L-shaped ferromagnetic material piece produced without requiring the production process of cutting or forging. Therefore, the yoke 14 can be easily manufactured.

[Fourth Embodiment] FIG. 6 is a perspective view of a yoke. In the fourth embodiment, detailed description of the same parts as those of the breaker trip device described in the above-mentioned conventional technique will be omitted.

The breaker tripping device of the fourth embodiment is different from the breaker tripping device described in the above-mentioned prior art in that it has the following features.

That is, as shown in FIG. 6, the tip portions of the side surface portions 3b and 3c of the yoke 3 are reduced in width to form a trapezoid, and the surfaces I and J facing the movable iron piece 2 are the same as those of the conventional yoke. This is a configuration that is approximately half the area.

Generally, the suction force F is expressed by the following equation.

[0040]

[Equation 1]

In equation (1), φ is the magnetic flux in the gap, μ0 is the magnetic permeability of air, and S is the cross-sectional area of the gap.

In an electromagnet device such as a relay, since a region that is not magnetically saturated is used, the gap cross-sectional area S
Is increased, the magnetic flux decreases from the gap due to the decrease in magnetic resistance.
Becomes larger. In this case, since the increase in the square of the gap magnetic flux φ is larger than the increase in the gap cross-sectional area S, the attractive force F increases. However, in the short-circuit sensor of the breaker, since the magnetically saturated region is also used, even if the gap section cross-sectional area S is increased, the gap section magnetic flux φ is not increased, and if the gap section cross-sectional area S is increased, the suction is attracted. The force F decreases.

Therefore, since the surfaces I and J of the yoke 3 facing the gap portion G corresponding to the area S of the cap portion are half the area of the same portion of the conventional yoke, the yoke 3
Even when the magnetic field is saturated and the magnetic flux φ in the gap portion does not increase, the attractive force F is approximately doubled. Therefore, when an overcurrent in a relatively large area flows, the movable iron core 2 is attracted to the yoke 3 and the electric path is cut off.

[Fifth Embodiment] FIG. 7 is a perspective view of a yoke. In the fifth embodiment, detailed description of the same parts as those of the breaker trip device described in the second embodiment will be omitted.

The breaker tripping device of the fifth embodiment is different from the breaker tripping device described in the second embodiment, and is characterized by the following structure.

That is, as shown in FIG. 7, a through hole 3d is provided in the bottom surface 3a of the yoke 3, and the through hole 3 is also provided in the ferromagnetic piece 13.
A screw hole 13a which is slightly smaller than d is provided, and the ferromagnetic material piece 13 is
The yoke 3 is screwed onto the inner surface of the body of the breaker by means of the ferromagnetic screw 15.

The total cross-sectional area of the ferromagnetic piece 13 and the bottom surface portion 3a of the yoke 3 is approximately twice the cross-sectional area of the cross-section E of the bottom surface portion 3a. Further, although the through hole 3d and the screw hole 13a are provided, the screw 15 is screwed, so that the total cross-sectional area does not decrease.

Therefore, the ferromagnetic piece 13 and the screw 15 are
The yoke 3 is attached to a predetermined position on the inner surface of the body of the breaker, and the total cross-sectional area of the bottom surface portion 3a of the yoke 3 is determined by the bottom surface portion 3.
The cross-sectional area of the cross section E of a is approximately doubled to prevent partial saturation of the yoke 3.

Therefore, the magnetic efficiency of the magnetic path composed of the yoke 3 and the movable iron core 2 does not decrease, the attraction force to the movable iron core 2 does not decrease, and when the overcurrent in a relatively large area flows, the movable iron core 2 is attracted to the yoke 3, and the electric path is cut off.

In the first to third and fifth embodiments, it is described that the total cross-sectional area of the bottom surface portion 3a is approximately doubled, but the value is limited to doubled. Instead, it is sufficient if the cross-sectional area of the bottom portion is increased.

Further, in the fourth embodiment, the description has been made assuming that the tip area of the side surface portion is halved, but the value is not limited to ½ and the tip portion is not limited to ½. Any area can be used as long as the area is reduced.

[0052]

Since the tripping device of the breaker of the present invention is constructed as described above, in the invention of claim 1, the cross section of the bottom portion of the U-shaped yoke is the cross section of the side portion. Since it is made thicker, partial saturation of the yoke does not occur, the magnetic efficiency of the magnetic path consisting of the yoke and the movable iron core does not decrease, and the attractive force to the movable iron core does not decrease, so when overcurrent flows, Has an effect that it is possible to provide a breaker tripping device in which the movable iron core is attracted to the yoke and the electric circuit can be surely cut off.

According to the second aspect of the present invention, since the plate-like ferromagnetic material piece is provided on the inner surface of the bottom surface of the yoke, it is possible to use a yoke that has already been manufactured, and The total cross-section including the cross-section of the bottom surface and the cross-section of the ferromagnetic piece is made thicker than the cross-section of the side surface, so that partial saturation of the yoke does not occur and the magnetic efficiency of the magnetic path consisting of the yoke and the movable core decreases It is also possible to provide a breaker tripping device that does not lower the attraction force to the movable iron core, and therefore, when an overcurrent flows, the movable iron core is attracted to the yoke and the electric circuit can be reliably cut off. It has the effect of being able to.

According to the third aspect of the invention, the yoke has two Ls each having an approximately uniform thickness and formed in an L-shape.
Since one surface of each of the U-shaped ferromagnetic material pieces is overlapped and the other surfaces of each of the ferromagnetic material pieces are opposed to each other to form a U-shape,
The magnetic efficiency of the magnetic path formed by the yoke and the movable iron core does not decrease, and the attraction force to the movable iron core does not decrease, therefore,
When the overcurrent flows, the movable iron core is attracted to the yoke, and it is possible to provide the trip device of the breaker that can surely interrupt the electric path.

According to the fourth aspect of the invention, since the tip of the side surface portion is narrowed to reduce the tip surface facing the movable iron piece, the yoke is saturated and the magnetic flux in the gap portion does not increase. Even when the overcurrent flows, the movable iron core is attracted to the yoke, and the breaker tripping device that reliably shuts off the electric path can be provided.

According to a fifth aspect of the present invention, a through hole is provided in the bottom surface of the yoke and the body of the breaker, a screw hole is provided in the ferromagnetic piece, and a screw of the ferromagnetic material is provided in the body of the breaker. Since it is inserted into the through hole and the through hole of the bottom surface of the yoke and screwed with the ferromagnetic piece, the ferromagnetic piece and the screw attach the yoke to a predetermined position on the inner surface of the body of the breaker. At the same time, the total cross section of the bottom surface of the yoke is thickened to prevent partial saturation of the yoke, the magnetic efficiency of the magnetic path consisting of the yoke and the movable iron core does not decrease, and the attraction force to the movable iron core does not decrease, Therefore, when the overcurrent flows, the movable iron core is attracted by the yoke, and it is possible to provide the breaker tripping device that can surely interrupt the electric path.

[Brief description of drawings]

FIG. 1 is a sectional view of a breaker trip device according to the present invention.

FIG. 2 is a perspective view of a yoke.

FIG. 3 is an explanatory diagram of a method of manufacturing a yoke.

FIG. 4 is a perspective view of a yoke.

FIG. 5 is a perspective view of a yoke.

FIG. 6 is a perspective view of a yoke.

FIG. 7 is a perspective view of a yoke.

FIG. 8 is a cross-sectional view of a conventional trip device for a breaker.

FIG. 9 is a cross-sectional view of a yoke.

FIG. 10 is a perspective view of a yoke.

FIG. 11 is a cross-sectional view illustrating saturation of the yoke.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric circuit 2 Movable iron piece 3 Yoke 3a Bottom part 3b Side part 3c Side part 3d Through hole 13 Ferromagnetic material piece 13a Screw hole 14 Yoke 14a L-shaped ferromagnetic material piece 14b L-shaped ferromagnetic material piece

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoyuki Sawada 1048, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd.

Claims (5)

[Claims] 1. A U-shaped yoke having an electric path, a bottom surface portion and side surface portions extending from both ends of the bottom surface portion and facing each other, and a U-shaped yoke surrounding the electric path by the bottom surface portion and the side surface portion, and a tip of the side surface portion of the yoke. And a movable iron piece that is attracted by the excited yoke when an overcurrent flows in the electric path and interrupts the electric path, in the trip device of the breaker, the cross section of the bottom surface of the U-shaped yoke is a side surface. A device for tripping a breaker, which is thicker than the cross section of the portion. 2. A U-shaped yoke having an electric path, a bottom surface portion and side surface portions extending from both ends of the bottom surface portion and opposed to each other, and enclosing the electric path with the bottom surface portion and the side surface portion, and a tip of the side surface portion of the yoke. A tripping device of a breaker having a movable iron piece that opposes to and that is attracted to a yoke excited when an overcurrent flows in the electric path to cut off the electric path. A device for tripping a breaker, characterized in that a body piece is provided, and a total cross-section including a cross-section of a bottom surface portion of a yoke and a cross-section of a ferromagnetic material piece is made thicker than a cross-section of a side surface portion. 3. A U-shaped yoke having an electric path, a bottom surface portion and side surface portions extending from both ends of the bottom surface portion and facing each other, and a U-shaped yoke surrounding the electric path by the bottom surface portion and the side surface portion, and a tip of the side surface portion of the yoke. And a movable iron piece that is attracted to a yoke excited when an overcurrent flows in the electric path and shuts off the electric path when the overcurrent flows in the electric path. A device for tripping a breaker, characterized in that one of the two L-shaped ferromagnetic pieces formed in a shape is overlapped with each other, and the other surfaces of the two pieces are opposed to each other to form a U-shape. . 4. A U-shaped yoke having an electric path, a bottom surface portion and side surface portions extending from both ends of the bottom surface portion and facing each other, and a U-shaped yoke surrounding the electric path by the bottom surface portion and the side surface portion, and a tip of the side surface portion of the yoke. A tripping device of a breaker having a movable iron piece that is attracted by a magnetized yoke and shuts off the electric path when an overcurrent flows in the electric path in the trip device of the breaker. Breaker tripping device characterized in that the tip surface is made smaller. 5. A through hole is provided in the bottom surface of the yoke and the body of the breaker, a screw hole is provided in the ferromagnetic piece, and a screw of the ferromagnetic material is provided between the through hole of the body of the breaker and the bottom surface of the yoke. 3. The breaker trip device according to claim 2, wherein the trip device is inserted into the through hole and screwed with the ferromagnetic piece.