JP3052631B2 - Circuit breaker - Google Patents

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 gas discharge path.

[0002]

2. Description of the Related Art In a circuit breaker of this type, a high-temperature gas generated when an abnormal current such as a short-circuit current flows and is cut off is discharged to the outside from a gas discharge passage provided in a case.
The case is made of an insulating material such as plastic, so the parts exposed to the passage of hot gas are burned
(Carbonization) in such a case, and in such a case, insulation is deteriorated and insulation performance is deteriorated. Since the gas discharge channel is accessible to the outside end (exhaust port), special care must be taken to prevent insulation degradation due to hot gas.

In order to solve this problem, as shown in FIG. 5, there is a prior art in which a perforated exhaust plate H made of an insulating material is disposed near an outer end (exhaust port) of a gas exhaust passage. In the figure,
1 is a case, 3 is a contact accommodating chamber, 4 is a gas discharge path, 11 is a contact device having a fixed contact 12 or a movable contact 14, 16 is a contact opening / closing mechanism having a handle 17, a cradle 18 and a reversing spring 19, Reference numeral 20 denotes an abnormal current detection device having a bimetal 21 and a latch movable piece 23. The perforated exhaust plate H prevents foreign matter from entering the case 1 and restricts the amount of high-temperature gas discharged to prevent insulation deterioration on the outer side.

[0004] In some cases, a step is provided at an outer end (exhaust port) of a gas discharge path. In the case where the step is provided, the outer portion after the step is less likely to be exposed to the high-temperature gas, and the creepage distance from the insulation-deteriorated portion is increased, thereby preventing the outer portion from deteriorating in insulation.

[0005]

The former circuit breaker described above is preferable in terms of ensuring insulation performance.
If the number of parts is increased or the assembling work becomes troublesome, and if the amount of discharged high-temperature gas is excessively restricted, the internal pressure may be increased and the shutoff performance may be reduced.

[0006] In the latter circuit breaker, there is a question about the assurance of the reliable insulation performance with a simple step. That is, even if the insulation deterioration on the outer side portion can be prevented, if the depth of the step is not sufficient, a human hand touches the portion where the insulation deterioration has occurred, and there is a safety problem. On the other hand, when the depth of the step is increased, the whole becomes larger.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a circuit breaker that does not allow a human to touch a portion of a gas discharge passage where insulation is deteriorated. Another object of the present invention is to provide a circuit breaker that can ensure insulation performance.

[0008]

According to a first aspect of the present invention, there is provided a circuit breaker in which a contact device, a contact opening / closing mechanism, an abnormal current detection device, and the like are housed in a case made of an insulating material. In the circuit breaker having a gas discharge passage communicating with the contact accommodating chamber for discharging gas generated at the time of contact opening / closing operation in the case, the gas discharge passage forms a gas discharge passage at an outer end thereof. The configuration is such that an enlarged diameter portion having a predetermined amount and a predetermined depth greater than the entire circumference of the inner contour is formed.

Further, the circuit breaker according to claim 2 has a configuration in which a plurality of gas discharge paths according to claim 1 are formed.

[0010]

According to the configuration of the first aspect, even if the inner part of the gas discharge path is deteriorated in insulation, the insulation resistance test using the test finger specified by the Electrical Appliance and Material Control Law can be cleared and the insulation deterioration can be achieved. It can be ensured that human hands do not touch the part that has been made.

According to the second aspect of the present invention, in addition to the operation of the first aspect, the high-temperature gas can be satisfactorily exhausted, and the shut-off performance can be reliably ensured.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. Members having the same basic functions as those of the conventional one are denoted by the same reference numerals.

Reference numeral 1 denotes a case, which is formed by abutting two case halves (base and cover) 2, 2 formed in a box shape having an opening on one side with an insulating material such as phenol resin, for example. (Not shown). Case 1 is a contact device that is a common component of circuit breakers.
11, contact switching mechanism 16, abnormal current detection device 20, frame
It houses 24 mag.

The contact device 11 has a fixed contact 12 to which a fixed contact 13 is fixed and a movable contact 14 to which a movable contact 15 is fixed. The contact opening / closing mechanism 16 includes a handle 17 and a cradle 18
And a reversing spring 19 and the like that are compression-suspended between the cradle 18 and the movable contact 14 to drive the movable contact 14. The abnormal current detecting device 20 is fixed to the bimetal 21 via the bimetal 21 and the leaf spring 22, and has a latch movable piece 23 for locking and releasing the cradle 18 and the like. The frame 24 supports and fixes each member.

In the case 1, the upper and lower walls and the left and right side walls are not uniform in thickness, and the inner wall side considers the arrangement, fixation, positioning, etc. of the members to be housed, and the outer wall side considers attachment and attachment of terminal members. And design as appropriate. Below the inside of the wall of the case 1, there is a contact accommodating chamber 3 for accommodating fixed and movable contacts 13 and 15, and for allowing the movable contact 15 to open and close. In order to discharge gas generated at the time of the contact opening / closing operation, a gas discharge passage 4 for communicating the contact housing chamber 3 with the outside is formed with a side wall cut off. In this embodiment, the gas discharge path 4 is provided on both the power supply terminal side and the load terminal side.

More specifically, the gas discharge path 4 is
It is formed by branching into a discharge path 5 and a second discharge path 6. After branching, the two discharge passages 5 and 6 have a rectangular cross section and have an inner contour having a predetermined dimension, and are directed outward, and formed with enlarged diameter portions 7 and 8 at their outer ends. The enlarged diameter portions 7, 8 are important in order to prevent human hands from touching the inner portion of each of the discharge passages 5, 6, which form the inner contour, and to prevent the whole from becoming larger. It is larger by a predetermined amount and has a predetermined depth with respect to the outline.

In this embodiment, the length L1 of the short side of the inner contour
Is L1 ≦ 2.8mm, and the extension L2 from the inner contour is L2 ≦ 1.0mm
And the depth L3 is set to 1.0 mm ≦ L3 ≦ 2.0 mm. this is,
The test finger specified by the Electrical Appliance and Material Control Law shown in FIG.
8 satisfies the condition that it does not contact the inner part of each of the discharge paths 5 and 6 forming the inner contour and clears the specified insulation resistance test.

Reference numeral 25 denotes a terminal device on the power supply side, and the terminal plate also serves as the fixed contact 12, to which a terminal screw 27 is screwed through a washer 26. 28 is a terminal device on the load side,
Terminal screw 31 is screwed into 29 through washer 30. Reference numeral 32 denotes a braided wire for electrically connecting the load-side terminal plate 29 and the bimetal 21.

In this circuit breaker, as shown in FIG. 1, the cradle 18 is latched to the latch movable piece 23 in a latched state, and the reversing spring 19 presses the movable contact 14 to close both contacts 13, 15. When the abnormal current detection device 20 is activated due to an overcurrent or a short-circuit current flowing in the configuration state, the cradle 18 is disengaged from the latch movable piece 23 and performs a trip operation. That is, the cradle 18 rotates counterclockwise by the spring force of the reversing spring 19,
Eventually, the direction of action of the spring force of the reversing spring 19 on the movable contact 14 is reversed, and both contacts 13 and 15 are opened to cut off the electric circuit. At this time, an arc is generated between the two contacts 13 and 15, and a high-temperature gas is generated in accordance with the arc. However, the arc is extended and current limiting is interrupted, and the high-temperature gas is discharged to the gas discharge path 4, that is, the first and second gas. It is discharged to the outside through the discharge paths 5, 6.

During the discharge of the high-temperature gas, the inner parts of the first and second discharge paths 5, 6 which define the inner contour may be exposed to the high-temperature gas to deteriorate the insulation. Since the large-diameter portions 7, 8 at the end portions are not exposed to the high-temperature gas, insulation deterioration does not occur. Therefore, the first and second discharge paths 5,
6 Even if the inner part of the insulation deteriorates, even if human hands touch the large diameter parts 7, 8 of the parts, they will not touch the deteriorated part of the insulation, and the test finger specified by the Electrical Appliance and Material Control Law shall be used. The insulation resistance test can be cleared. Further, since the exhaust plate is not used unlike the conventional one, the number of parts can be reduced, the assemblability can be improved, and the high-temperature gas can be evacuated satisfactorily, so that the shut-off performance can be ensured.

In the embodiment, a plurality of gas discharge paths are described, but the number may be determined as appropriate according to the shutoff performance. Further, the case has been described in which the case halves having substantially the same width are butted and caulked, but it is needless to say that one may be box-shaped and the other may be lid-shaped.

[0022]

The circuit breaker according to the present invention can clear the insulation resistance test using a test finger specified by the Electrical Appliance and Material Control Law even if the inner part of the gas discharge passage deteriorates in insulation. It is possible to ensure that the insulation-degraded portion is not touched by human hands.

According to the circuit breaker of the second aspect, in addition to the function and effect of the first aspect, the high-temperature gas can be satisfactorily exhausted, and the interruption performance can be ensured.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a side view in which one half of a case is removed.

FIG. 2 is a side view seen from a direction different from 90 ° in FIG. 1;

FIG. 3 is an enlarged view of a main part of FIG. 1;

FIGS. 4A and 4B are explanatory diagrams of a test finger specified in the Electrical Appliance and Material Control Law.

FIG. 5 is a side view showing a conventional example, in which the inside is seen.

[Explanation of symbols]

 1 Case 2 Case half body constituting the case 3 Contact housing chamber of the case 4 Gas discharge path 5 First discharge path of gas discharge path 6 Second discharge path of gas discharge path 7 Large diameter section of first discharge path 8 Second Large diameter section of discharge path 11 Contact device 16 Contact switching mechanism 20 Abnormal current detector 24 Frame

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tatsuo Hiroshima 1048 Kadoma Kadoma, Osaka Pref.Matsushita Electric Works, Ltd. References Hikaru Hei 1-159331 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01H 73/06 H01H 71/02

Claims (2)

(57) [Claims] 1. A gas discharge device which accommodates a contact device, a contact opening / closing mechanism, an abnormal current detection device, and the like in a case made of an insulating material, and communicates with a contact accommodating chamber in this case to discharge gas generated during the contact opening / closing operation. In the circuit breaker having a passage, the gas discharge passage is provided at its outer end with an expansion having a predetermined amount and a predetermined depth greater than the entire circumference of an inner contour forming the gas discharge passage. A circuit breaker formed with a diameter. 2. The circuit breaker according to claim 1, wherein a plurality of said gas discharge paths are formed.