JPS6139336A - Fuse - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a fuse that, when a short-circuit accident occurs in an electric circuit and excessive current flows, fuses to quickly cut off the current and protect equipment and circuits. It is.

[Conventional technology]

FIG. 6 and FIG.
2 is a cross-sectional view showing the conventional fuse and its operation display device shown in FIG. A terminal metal made of copper (3) is attached to the insulating tube (1) and connected to an electric circuit (not shown), and a terminal metal made of silver or the like is attached to the terminal metal (2). A main fuse element (4) made of a low-resistance material is installed on one terminal metal (2), and when the main fuse element (3) is blown, the display fuse element (1G) is blown and the display member (2) is blown. An operation display device that is projected to indicate that the fuse has operated; (6) is the operation display device 1;
The terminal metal (2) excluding the inside of (4) (filled in the insulating tube (1) closed with 21, and the fuse element (3)
This is an arc extinguishing agent made of silica sand that extinguishes the arc generated after the steel is fused. FIG. 7 shows the operation display device (4
], (6) is an enlarged view of one of the terminal metals (2) surrounding the opening (2a) made in the center of the terminal metal (2).
) is attached to the display chamber made of an insulator to prevent the arc extinguisher (5) from flowing in, (sb) is an opening provided at the bottom (6a) of the display chamber (6), and (7) is the display chamber (6). ) and has a cylindrical shape that is thinner than the opening (2a) of the terminal metal (2) and has a tip (7a).
) and a display cap (8) having a small opening (7b) at the other end and a flange (7C) larger than the opening (2a); (8) is housed in the display cap (7); 7), and the other end is in contact with the inner surface of the tip (7a) of the display chamber (
(9) a biasing device consisting of a push spring that comes into contact with the bottom (6a) of 6) and applies a biasing force to the display cap (7) so as to project outward from the opening (2a) of the terminal metal (2); is a head (9) larger than the tip opening (7b) of the display cap (7).
a) and the body (9b), which is thinner than the opening (7b), and the body (9b) is drawn into the inside through the tip opening (7b) of the display cap (7) and passes through the inside of the biasing device (8). an indicator rod which extends close to the bottom (6a) of the indicator chamber (6) and is adapted to allow the head (9a) to hold the indicator cap (7) when the body (9b) is held; (6)
The display member s Qo is composed of a display cap (7) and a display rod (9). Both ends of the display member s Qo are connected to the terminal metal (2) (21), and the display member s Qo is connected to the terminal metal (2) (21) and enters the display chamber (6) from the opening (6b) on the way. a display fuse element made of a high-resistance material such as nichrome wire, which passes through a cross hole (9C) at the opposite end of the body (9b) of the display rod (9) and holds the display member side; (b) By pressing the line display fuse element (1 (I) against the wall of the opening (6b) of the display chamber, the display fuse element σQ resists the biasing force of the biasing device (8) and displays the display member (2).
It is a wedge-shaped insulating plug that is fixed so as to hold it in a closed state.

FIG. 8 shows another example of the structure of the conventional fuse operation display device disclosed in Japanese Utility Model Application No. 58-140081, and is an enlarged cross-sectional view of the main part. In this example, the display member (2) and the biasing device (8) are housed in a recess (1a) provided in the insulating tube (1), and when the recess (1a) has the configuration shown in FIG. 7 above, It functions as a display room (6). In addition, the display fuse element α0 that holds the display member (2) in place has a small hole (1b) formed at the bottom of the recess (la).
) into the insulating cylinder, and by fixing both ends to the terminal metal under tension, the display member (2) can be held in place without being fixed by the plug (b) in the case of the configuration shown in Fig. 7 above. There is.

FIG. 9 shows yet another different configuration example of the conventional fuse operation display device shown in U.S. Pat. be.

In this example, the display device (4) is attached to one terminal metal (2) as in the case of the configuration shown in FIG. 7 above. In the figure, (2) is a cylindrical member made of copper or iron that surrounds the opening (2a) made in the center of the terminal metal (2) and is attached to the terminal metal (2), and cA4 is the cylindrical member (2).
It is a lid made of an insulating material that seals the end of the cylindrical member (14a) and has a small hole (14a) in the center.
18a). The display element αQ passes through the transverse hole (9C) of the display rod (9) and holds the display member side in place, and one end of it passes through the cylindrical part #1's protrusion (18b).
), and is further fixed by caulking, and the other end of 1 is pulled out through the small hole (14a) of the lid (B) and connected to the other terminal metal (2), and then the other end is pulled out through the small hole (14a) of the lid (B) and connected to the other terminal metal (2). 14
It is fixed with a crimp sleeve (g) at the point where it comes out from a). In this example, the cylindrical member 0 and the lid (B) form the display/chamber a, and only one of the display fuse elements αO, which holds the display member side, is led out from the display chamber QQ. This is a major difference from the case in Figure 5.

Next, the operation will be explained. Mainly Figures 6 and 7
Although the case of the configuration shown in the figure will be explained as an example, the case of the other configurations shown in FIG. 8 or FIG. 9 is basically the same.

Main fuse element (3) and display fuse element)
(L[) is electrically connected in parallel,
The main fuse element (3) is made of low resistance silver,
Since the display fuse element QG is made of high-resistance nichrome, most of the current normally flows through the main fuse element (3). If an excessive current such as a short circuit current flows through the fuse, the main fuse element (
3) melts and becomes high resistance, and the current flows to the display fuse element (10) and when the display fuse element (10) melts, an arc is generated in both the main fuse element (3) and the display fuse element head, and this arc The arc is extinguished by the action of the arc extinguisher (5), thereby cutting off the excessive current.Then, the display member (2), which is released from the hold by the display fuse (1G), is activated by the biasing device ( The terminal metal (2) moves outward from the opening (2a) by the biasing force of 8) and protrudes until the flange (7c) of the display cap (7) comes into contact with the inner surface of the terminal metal (2) and stops, thereby closing the fuse. indicates that it has operated.After the operation, the display member (2) is held back and the display chamber (6)
A hole aη as shown in FIG. 10 is formed where the part (10c) of the display fuse element led out into the arc-quenching agent (5).

Here, the display fuse element (10) is fused at the part (1(ia)) buried in the arc-extinguishing agent (6) with good thermal conductivity.
It first occurs in the air part (10b) with poor heat conduction that holds the display member (2) in the display chamber (6), and then progresses to the part in the arc-quenching agent (FOA). Generally, the (10) of the display fuse element is
a) Both (10b) are made to have the same thickness, but in order to more reliably melt the part (10b) that holds the display member 4 in place first, the part (tOa) in the arc extinguisher is thicker than the part (tOa). The portion (10b) that holds the member in place may be made thinner or made of a material with higher resistance.

[Problem that the invention seeks to solve]

In conventional fuses, the temperature inside the fuse becomes extremely high due to the occurrence of an arc following the melting of the fuse element due to excessive current, resulting in high pressure. Stop and display room (
6) The internal gas blows out from the hole (171) formed by fusing the part (10c) of the display fuse element leading from l (la), tH into the arc quenching agent (5),
Furthermore, this ejects out of the fuse from the opening (2a) of the terminal metal (2). After that, the heat from the fuse is gradually transferred to the surrounding air and is cooled down, until the temperature of the fuse becomes equal to the temperature of the atmosphere.

During the cooling period after this internal gas is released, the air pressure inside the fuse becomes negative, and this time, on the contrary, the atmosphere is sucked in through the hole Qη formed by melting the part (10c) of the fuse element shown above. do. At this time, if the atmospheric humidity is high, moisture will be sucked into the fuse, and especially if the fuse is for outdoor use and operates during rain, rainwater will be sucked in. Fuse element (
After the arc generated at 3) and oo is extinguished by the action of the surrounding arc extinguishing agent (6), this is due to the arc extinguishing agent (5) in which the constituent metals of the fuse element have diffused into the melted arc extinguishing agent (5). ) (FULGURITE), but when the above moisture is inhaled, this falgelite and the arc extinguisher absorb water, lowering the insulation resistance and causing another flash short. There was.

This invention was made to solve the above-mentioned problems, and the purpose is to obtain a fuse that does not inhale air or rainwater and does not cause re-flash even when the fuse is cooled down after operation. shall be.

[Means for solving problems]

The fuse according to the present invention is provided with a rubber-like member attached to the display chamber at a portion where the display fuse element leads out from the display chamber into the arc extinguisher, and the display fuse element is inserted through the rubber-like member or into the display chamber. This is derived from the boundary between the rubber-like member and the rubber-like member.

[Effect]

Even if the fuse in this invention operates and the internal pressure becomes high, the rubber member is pressurized and deformed, and the display fuse element melts and closes the hole formed, allowing the inner balance body to move outside. Avoid blowing out. Therefore, after cooling, high humidity air or rainwater is not inhaled, and flash flashing is prevented.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 8. Figures 1, 2, and 8 are Figures 7 and 8, respectively.
9 shows an example in which the present invention is applied to the fuse of the conventional structure shown in FIG.
+ (1a) + (to) is a rubber-like member attached to the above-mentioned display chamber in the part led out into the arc extinguisher (5), and the display fuse element <10 is this rubber-like member (material ) and is derived. The rest of the configuration is the same as the conventional one, so the explanation will be omitted.

Here, the rubber-like member (to) is a material that is elastic and has no air permeability, and is a constituent member (a) of the display chamber.
e Q) t a and display fuse element αO
A suitable material is one that adheres to the surface and acts as a seal. As an example of such a device, it has been confirmed through experiments that it is effective to apply liquid or grease-like silicone ATV rubber and harden it during the adhesion process after assembling the operation display device. Also displayed on silicone rubber)
It was also effective to stick silicone rubber with adhesive after penetrating the hole.

Next, the operation will be explained. The case of the configuration shown in FIG. 1 will be explained as an example, but the other configurations shown in FIG. 2 or FIG. 8 are basically the same.

Displayed when excessive current flows through the fuse (fuse) (
When 1. is fused, the unretained display part is pressed against the opening (2a) of the terminal metal (2) by the biasing force of the biasing device (8).
) to indicate that the fuse has operated, but
At this time, after operation, the part (10
A small hole α as shown in Figure 6 is created where there was c), but the temperature inside the fuse is low (3)
(Due to the melting of the JO and the generation of the arc, the pressure has become very high, so even if the gas inside the fuse tries to blow out through the small hole (to) above, it will not flow as shown by the arrow in Figure 5. The rubber-like member is pressurized and deformed by the high pressure from the surrounding area, closing the small hole a and preventing the gas inside the fuse from blowing out to the outside.Therefore, even if the fuse cools down afterwards, Unlike fuses, the internal pressure becomes negative and air and rainwater are not inhaled. Therefore, there is no drop in insulation resistance due to water absorption by falgelite and arc quenching agent, eliminating the risk of re-flash short circuiting. Can be done.

In the above embodiment, the display fuse element 01) is connected to the arc extinguisher (6) from the display chamber (6);
A rubber-like member (7) is attached to the partial positive display chamber leading into the display fuse element (6), and the display fuse element (10) is inserted through this rubber-like member (to). However, as shown in FIG. 4, the display fuse element Ql) may be led out from the boundary between the display chamber and the rubber-like member.

In addition to the above-mentioned structure, the operation display device may be installed protruding outside the terminal metal as shown in Fig. 1 of JP-A-57-101818, and there are various other structures. The present invention is also effective for operation display devices having different configurations.

Furthermore, in the above embodiment, the main fuse element (3) and the display fuse element (Qtl) are provided in parallel. However, in the case of a fuse with an extremely small rated current, the display fuse element QO may also serve as the main fuse element (3), and the present invention is also effective for such a fuse.

〔Effect of the invention〕

As described above, according to the present invention, since the rubber-like member attached to the display chamber is provided at the part where the fuse element leads out from the display chamber into the arc extinguisher, even if the fuse operates and the internal pressure becomes high pressure. Internal gas does not blow out to the outside, and high humidity air and rainwater are not inhaled after cooling, which has the effect of preventing a drop in insulation resistance and re-flash shorting.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a fuse according to an embodiment of the present invention, particularly showing its operation display device and its vicinity, and FIGS. 2 and 8 are cross-sectional views showing examples in which the present invention is implemented in fuses of other different structures. 4 is a cross-sectional view showing a fuse operation display device and its vicinity according to another embodiment of the present invention, FIG. 5 is a cross-sectional view showing the main part of the fuse of the present invention after operation, and FIG. is a cross-sectional view of a conventional fuse,
7 to 9 are sectional views showing different conventional fuse operation display devices and their vicinity, and FIG. 10 is a sectional view showing the main parts of the conventional fuse after operation. In the figure, (4) is an operation display device, (5) is an arc extinguisher,
(6) * (la) a 04 is a display chamber, (8) is a biasing device, Ql) is a Hahi W-'s element, (2) is a display member, and (to) is a rubber-like member. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (3)

[Claims] (1) A display member, a biasing device that biases the display member to protrude from the fuse, a display chamber that houses the display member and the biasing device, and a display chamber that is normally connected to the biasing force of the biasing device. a fuse element that resists the display member and releases the display member by fusing when activated;
In a fuse including an arc extinguishing agent filled in the fuse except for the display chamber, a rubber-like member attached to the display chamber is provided at a portion where the fuse element leads out from the display chamber into the arc extinguisher. . A fuse, characterized in that the fuse element passes through the rubber-like member or is led out from a boundary between the display chamber and the rubber-like member. (2) The fuse according to claim 1, wherein the rubber-like member is silicone RTV rubber that is in a liquid or grease state during the adhesion process and is hardened after the adhesion process. (3) The fuse according to claim (1), characterized in that a rubber-like member is attached to the display chamber.