JPH0668768A - Circuit breaker - Google Patents

Abstract

PURPOSE:To increase short-circuit breaking capacity only by addition of a small part while using a comparatively inexpensive material as a case by arranging an insulating color in the middle of an air exhaust passage, and forming the insulating collar of a material having excellent arc resistance. CONSTITUTION:An air exhaust passage 1a and a slightly long recessed place 2a to communicate space where fixed and movable contact points 5 and 7 carry out opening and closing operation with the outside, are arranged in a thick wall part of the left and right side walls of a body 2 constituting a case 1, and an installation part 2g in which an insulating collar 23 is embedded, is arranged consecutively in a part of the recessed place 2a. This color 23 is molded in a square cylinder shape having comparatively short axial directional length by means of a material having excellent arc resistance, and is embedded in the installation part 2g of the body 2. Arc gas generated when both the contact points 5 and 7 are opened separately, passes through the collar 23 when being discharged through the air exhaust passage 1a. Thereby, since insulation can be secured between an inside charging part and an outside port end of the air exhaust passage 1a, short-circuit breaking capacity can be increased only by adding a small part while using a comparatively inexpensive material as the case 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker using a case made of a relatively inexpensive insulating material.

[0002]

2. Description of the Related Art There is a general circuit breaker having a structure shown in FIG. In the figure, reference numeral 2 denotes a body that constitutes a case 1 made of an insulating material such as plastic together with a cover outside the figure, and has a box-like shape with one surface open. 4 is a fixed contact with fixed contact 5, 6 is a moving contact
Movable contact with 7, 8 is handle, 9 is handle 8
The opening / closing mechanism section including the handle 8 that opens and closes the fixed and movable contacts 5 and 7 by the operation, and 13 is the abnormal current detection means that acts on the opening and closing mechanism section 9 to perform the trip operation when an abnormal current flows. .

The case 1 has fixed and movable contacts 5, 7
Exhaust passage 1a for communicating the space where the person opens and closes to the outside
have. This exhaust passage 1a has fixed and movable contacts 5,7.
The arc gas generated when is separated is discharged to the outside.

In such a circuit breaker, when a large amount of high-temperature arc gas is generated and exposed to the case 1 like short circuit interruption, the exhaust passage 1a of the case 1 and its surroundings may be carbonized. is there. Then, the internal charging section and the exhaust passage 1a
The insulation performance between the outer rims of the will deteriorate, resulting in a risk of electric shock.

Therefore, when the case 1 is made of a relatively inexpensive plastic, that is, a material having normal arc resistance, the short circuit breaking capacity becomes small. In order to increase the short-circuit breaking capacity, Case 1 had to be made of an expensive material having good arc resistance.

By the way, in a circuit breaker in which cost reduction is also an important issue, there is a demand to use a relatively inexpensive plastic case and to increase the short-circuit breaking capacity. Therefore, for example, it has been proposed that convex portions and concave portions are alternately formed in the exhaust passage along the longitudinal direction thereof to increase the creepage distance between the internal charging portion and the outer rim of the exhaust passage. In addition, Japanese Patent Publication No. 32-8831 proposes a method in which a silicone resin is applied to a portion where insulation deterioration occurs.

[0007]

In the above-mentioned exhaust passage, the convex portions and the concave portions are alternately formed along the longitudinal direction of the exhaust passage to increase the creepage distance between the internal charging portion and the outer edge of the exhaust passage. There is no change in that the parts and the recesses deteriorate, and although the short-circuit breaking capacity is small, there is an effect in improving safety, but it is not so much expected to increase the short-circuit breaking capacity.

Further, although the one proposed in Japanese Patent Publication No. 32-8831 is effective in increasing the short-circuit breaking capacity, the coating process of the silicone resin is troublesome and the cost reduction cannot be expected so much.

The present invention has been made in view of the above circumstances, and an object thereof is to make a circuit breaker capable of increasing a short-circuit breaking capacity by adding a small component while using a relatively inexpensive material for a case. To provide the vessel.

[0010]

In order to solve the above problems, a circuit breaker according to the present invention includes a fixed contact having a fixed contact, a movable contact having a movable contact, and a fixed contact by a handle operation. An opening / closing mechanism section including a handle for opening / closing the movable contact, an abnormal current detecting means that acts on the opening / closing mechanism section to perform a trip operation when an abnormal current flows, and the above-mentioned members are housed and arc gas is discharged. In a circuit breaker provided with an insulating material case having an exhaust passage, an insulating collar through which arc gas passes is disposed in the middle of the exhaust passage, and the insulating collar is made of a material having good arc resistance. It is formed as a structure.

Further, the case is composed of a box-shaped body having a substantially one-sided opening and a flat plate-like cover, and a recess which serves as a substantial exhaust passage is formed in the body, and an insulation is provided in a part of the recess. It is preferable that a mounting portion in which the collar can be fitted is continuously provided.

[0012]

According to this structure, even if the insulation of the exhaust passage is deteriorated, the insulating collar made of a material having a good arc resistance is disposed in the middle of the exhaust passage. Insulation between outer rims can be secured.

Further, if the mounting portion is connected to the body, the process of fitting the insulating collar can be simplified.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In addition, the same code | symbol is attached | subjected to the member with the same basic function as the conventional thing.

Reference numeral 1 denotes a case, which is composed of a body 2 and a cover 3 which are made of a relatively inexpensive insulating material such as general-purpose phenol resin. The body 2 is in the shape of a box with one side open, and has a handle opening 2b on the top wall and fixed contact attachments 2c and terminal board attachments 2d on the left and right sidewalls that are cut out from the opening end. There is. The upper and lower walls and the left and right side walls are not of uniform thickness, and the inner wall side is appropriately designed in consideration of the arrangement, fixing, positioning, etc. of the member to be housed, and the outer wall side is designed in consideration of the attachment of the terminal member. In these thick-walled parts, tapping screws 21 and 21, fixing holes 2e and 2e for fixing the cover, and relief parts 2f and 2f for the terminal screw, as well as a space for opening and closing the fixed and movable contacts, which will be described later, are provided. A slightly long recess 2a is provided which serves as an exhaust passage 1a for communicating with the outside. That is, the exhaust passage 1a is formed by closing the recess 2a with the cover 3.

Further, a mounting portion 2g into which an insulating collar described later can be fitted is connected to a part of the recess 2a. In addition, a fulcrum portion 2h of the handle, a support portion 2j of the frame, etc. are provided on the bottom.

The cover 3 has a flat plate shape that closes the opening of the body 2 and has insertion holes 3e, 3e, ─ for the tapping screws 21, 21, ─ at positions corresponding to the pilot holes 2e, 2e, ─. is doing.

Reference numeral 4 denotes a fixed contact, which is bent to have a length from the inside to the outside of the body 2 when mounted on the fixed contact mounting portion 2c. The fixed contact 4 has a fixed contact 5 fixed to one end located on the inner side of the body 2, and the other end on the outer side also serves as a terminal plate. Therefore, the terminal screw 22 is screwed.

Reference numeral 6 denotes a movable contactor, which has a fixed contact 5 and a movable contact 7 for contacting / separating fixedly attached to one end located below, and a rotatable contact to the other end located above to be rotatably supported by a handle. A spring bearing 6b of a reversing spring is provided in the moving shaft 6a and an intermediate portion.

Reference numeral 8 denotes a handle, which is interlocked with the movable contact 6 in cooperation with an opening / closing mechanism portion described later. The handle 8 has a rotation fulcrum 8h located below it supported by the fulcrum 2h of the body 2, an operation part 8b located above it protruding from the handle opening 2b, and a cradle pressing part 8c to be described later in the middle. Have
It supports the movable contact 6 described above.

Reference numeral 9 denotes an opening / closing mechanism portion including the handle 8, which opens and closes the fixed and movable contacts 5 and 7 by operating the handle 8 and performs a trip operation when an abnormal current detecting means described later operates. The opening / closing mechanism unit 9 includes a cradle 10, a frame 11 that supports the cradle 10, a reversing spring 12, and the like. The frame 11 has a fitting portion 11j fitted to the support portion 2j of the body 2 on the base portion 11a, and the support piece 11b of the cradle 10 and a bimetal support piece 11c described later are formed by bending.

The cradle 10 has a generally V-shape, one end of which is movably supported by a supporting piece 11b of the frame 11, and the other end of which is a locked portion 10a which is locked by an abnormal current detecting means described later,
In the middle part, the spring bearing 10b of the reversing spring and the pressing part of the handle 8 are
It has a pressed portion 10c corresponding to 8c. Reversing spring 12
Is in the form of a coil, and has movable contact 6 and cradle 10
It is compression-suspended between the spring supports 6b and 10b. Therefore the reversing spring
The spring 12 always biases the cradle 10 in the counterclockwise direction, and biases the movable contact 6 in the contact point contact direction or the contact point separation direction depending on the positions of the handle 8 and the cradle 10.

Reference numeral 13 is an abnormal current detecting means, which acts on the opening / closing mechanism section 9 to perform a trip operation when an abnormal current flows in the electric path. The abnormal current detection means 13 is composed of a bimetal 14, a suction piece 15, a locking piece 16, an elastic piece 17, and the like. Bimetal 14
The base end of the elastic piece 17 is fixed to the bimetal support piece 11c of the frame 11, the base end of the elastic piece 17 is fixed to the tip end, and the suction piece 15 is held in the middle part. The attracting piece 15 is a U-shaped magnetic plate material. The locking piece 16 has a long plate shape made of a magnetic plate material, and has a rectangular opening at the center thereof, and its upper end surface is used as a locking portion 16a for locking the locked portion 10a of the cradle 10,
The base end is fixed to the tip of the elastic piece 17. In this case, the locking piece
16 is positioned so as to face the end surface of the suction piece 15.

In the abnormal current detection means 13, when an overcurrent flows in the bimetal 14 and it is deformed, the locking piece 16 also moves accordingly, and a short-circuit current flows in the bimetal 14 to cause an adsorption piece.
When a large magnetic flux flows to 15, the locking piece 16 immediately sucks.
It is attracted to the end face of 15 and moves. That is, when an abnormal current such as an overcurrent or a short-circuit current flows in the electric circuit, the locked portion 10a of the cradle 10 is released from the locking portion 16a to perform the trip operation.

18 is a terminal board, 19 is a terminal board 18 and a bimetal 14.
A braided wire for connecting the bimetal 14 and the movable contact 6 is shown at 20.

Reference numeral 23 denotes an insulating collar, which is made of a material having a good arc resistance and is formed into a rectangular tube shape having a relatively short axial length.
It is fitted into the mounting part 2g of the body 2. Insulation collar 23 is
It is attached by attaching the cover 3 to the body 2 with the tapping screws 21, 21 ,. Therefore, the arc gas generated when the contacts 5, 7 are separated from each other passes through the insulating collar 23 when being discharged through the exhaust passage 1a. Materials having good arc resistance are as follows, and the value in [] is the value [sec] indicating the arc resistance of each material.

Unsaturated polyester resin (120-240), melamine resin (110-140), epoxy resin (120-180), PET
(120-130), PBT (75-192), polyamide resin (130-
140), fluororesin (300 or more), electrical phenolic resin (1
08-180). The general-purpose phenol resin used for Case 1 is 10 seconds or less.

FIG. 1 shows a state in which the handle 8 is switched from the ON position to the OFF position, and the locked portion 10a of the cradle 10 is locked to the locking portion 16a of the locking piece 16. At this time, the reversing spring 12 biases the movable contact 6 toward the contact opening side. If handle 8 is rotated counterclockwise from this state,
Turns on. That is, the rotation shaft 6a of the movable contact 6 moves as the handle 8 rotates, and the spring biasing direction of the reversing spring 12 with respect to the movable contact 6 reverses to the contact point contact direction.

In this ON state, when an abnormal current flows in the electric path, the abnormal current detection means 13 operates to release the locked portion 10a of the cradle 10 from the locking portion 16a, and the spring force of the reversing spring 12 causes Rotate the cradle 10 counterclockwise. When the cradle 10 rotates by a certain amount, the spring receiver 10b reaches a position where the spring urging direction of the reversing spring 12 with respect to the movable contact 6 is reversed, and the spring urging direction of the reversing spring 12 becomes the contact opening direction. When it is reversed, the contacts are opened as shown in FIG. 3, and the trip operation is performed. Then, when the trip operation, that is, when both contacts 5 and 7 are separated, arc A and arc gas G are generated, and the high temperature arc gas G is discharged through the exhaust passage including the insulating collar 23.
It passes through 1a and is discharged to the outside.

Since the exhaust passage 1a is formed of general-purpose phenol resin, it is likely to cause insulation deterioration due to exposure to the high-temperature arc gas G, but the insulating collar 23 exists in the middle of the exhaust passage 1a. Insulation can be secured between the internal charging part and the external rim of the exhaust passage. The inventors of the present application measured the insulation resistance after short-circuit interruption for the insulation collar 23 having an axial length L of 1 mm, 2 mm, 4 mm, and 6 mm. Insulation resistance is 12
Value after repeating 0V / 10kA interruption twice, 0.4M in sequence
Ω, 1MΩ, 10MΩ, 30MΩ. Therefore, to ensure this level of breaking capacity, the axial length of the insulation collar 23
L should be 2 mm or more.

The shape of the insulating collar can be molded,
Any suitable material may be adopted as long as it can be fitted in the mounting portion of the body and the arc gas can pass therethrough. Further, the present invention can be applied to various types of circuit breakers except for the structure around the exhaust passage.

[0032]

In the circuit breaker according to the first aspect of the present invention, since the insulating collar formed of a material having a good arc resistance is disposed in the middle of the exhaust passage even if the insulation of the exhaust passage deteriorates,
Insulation can be secured between the internal charging part and the outer rim of the exhaust passage, so that the short-circuit breaking capacity can be increased simply by adding small parts while using a relatively inexpensive material for the case.

According to the circuit breaker of the second aspect, in addition to the effect of the first aspect, the process of fitting the insulating collar can be simplified.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention with a cover removed.

FIG. 2 is an exploded perspective view thereof.

FIG. 3 is a side view showing a state where the trip operation is performed.

FIG. 4 is a side view showing a conventional example without a cover.

[Explanation of symbols]

 1 Case 1a Case exhaust path 2 Body that forms the case 2a Body recess that forms the exhaust path 2g Body mounting part 3 Cover that forms the case 4 Fixed contact 5 Fixed contact 6 Moving contact 7 Moving contact 8 Handle 9 Opening / closing mechanism section 10 Cradle constituting the opening / closing mechanism section 11 Frame constituting the opening / closing mechanism section 12 Reversing spring constituting the opening / closing mechanism section 13 Abnormal current detecting means 14 Bimetal constituting abnormal current detecting means 15 Comprising abnormal current detecting means Adsorption piece 16 Locking piece that constitutes abnormal current detection means 17 Elastic piece that constitutes abnormal current detection means 23 Insulation collar A Arc G Arc gas

Claims (2)

[Claims] 1. A fixed contact having a fixed contact, a movable contact having a movable contact, an opening / closing mechanism section including a handle for opening and closing the fixed and movable contacts by operating a handle, and an abnormal current flowed. In a circuit breaker provided with an abnormal current detection means that sometimes acts on the opening / closing mechanism to perform a trip operation, and a case made of an insulating material having an exhaust passage for accommodating each member and discharging arc gas,
A circuit breaker characterized in that an insulating collar through which arc gas passes is disposed in the middle of the exhaust passage, and the insulating collar is made of a material having good arc resistance. 2. The case comprises a box-shaped body having a substantially one-sided opening and a flat plate-like cover, and a recess is formed in the body as a substantial exhaust passage, and insulation is provided in a part of the recess. The circuit breaker according to claim 1, further comprising a mounting portion to which the collar can be fitted.