JP2530294Y2 - High current fuse - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a high-current fuse connected for protection to, for example, a starter motor of an automobile.

2. Description of the Related Art Conventionally, large current fuses used for protecting a motor load circuit such as a power window circuit of an automobile are disclosed in Japanese Utility Model Publication Nos. 59-41563, 59-66874 and 60-6774.
No.-6988, Japanese Utility Model Application Laid-Open No. 61-96442, and the like. For example, as shown in FIG.
It is composed of a plate-shaped fuse element 2 and a heat absorber 14. When a current flows and heat is generated in the fuse element 2 of this fuse, this heat is transmitted to the heat absorber 14 and is also conducted to the terminal 3, so that it is cut off for a short-time transient current or a lock current. It has a slow blow characteristic that cuts off when the layer is short-circuited.

In the above conventional fuse for a large current, which has this characteristic,
A high-melting point metal material having a melting point of about 1000 ° C. punched out of a copper alloy thin metal plate is used.

[Problems to be solved by the invention]

However, in the above-mentioned high current fuse, since a high melting point metal material is used, the fuse element is held at a high temperature of about 1000 ° C. for a long time in the case of a layer short, that is, in a fusing region. In some cases, the resin case may be damaged, and in the worst case, the case may be melted. Further, in the fusing region, the amount of heat transferred from the fuse element to the fuse terminal to the connection wire increases, and there is a risk that the insulation coating of the connection wire melts and emits smoke.

Accordingly, there has been no large-current fuse used for protection of a starter motor for an automobile or the like which has to handle a larger current than a conventional large-current fuse using a power window or the like.

Here, as one solution to the above problem, as shown in FIGS. 6 (a) and 6 (b), a fuse element 2 made of a low melting point alloy is provided between two heat storage blocks 1 for lowering the fusing temperature of the fuse. It is conceivable that the element 4 is formed by attaching one end of the fuse terminal 3 to each heat storage block, and the element 4 is housed in the resin case 6 and the melt stopper 9 is fitted below the element 4.

However, it is difficult to handle a very large current with a fuse simply using a low melting point alloy, and if the fuse is not blown badly at the time of blowing, the fuse will not be normally blown as shown in FIG. As described above, the fuse accumulated in the stopper 9 may be in a bridge state with the regenerator block 1 to keep energizing the circuit and melt the case 6.

In view of the above, an object of the present invention is to reduce the melting temperature by using a low melting point alloy by devising the element, and to further ensure that the circuit is cut off by a fuse.

[Means for solving the problem]

In order to solve the above problems, a fuse element is provided between a pair of heat storage blocks having terminals to which electric wires and cables are connected to form an element, and the element is housed in a resin case and projected out of the terminal case. And a fuse for a large current provided with a stopper for storing a molten material below the fuse element, wherein the element is a block body integrally cast from molten metal, and the volume of each heat storage block is the volume of the fuse element. While larger than the above, the element is formed of a Sn-Pb alloy, a Sn-Bi alloy, or a low melting alloy obtained by adding an additive to a Sn-Bi alloy, and the fusing temperature of the fuse element is set to 120 ° C or more. 335 ° C
The fuse element is blown below the fuming temperature (150 ° C. to 200 ° C.) of the insulating coating of the cable in which the fuse element is used.

At this time, a partition may be provided on the upper surface of the melt reservoir of the stopper in parallel with the heat storage block, and the partition may be formed close to the top fuse element of the partition.

Further, the fuse for a large current can be used in a starter motor circuit for a vehicle.

[Action]

In the thus configured high current fuse according to the present invention, when a current flows, the fuse element generates heat, and this heat is conducted from the fuse element to the fuse terminal, and a larger volume than the interposed fuse element. The heat is stored in the heat storage block and the amount of heat transferred to the fuse terminal is reduced. Therefore, the fuse element does not blow at a steady current, and the insulating coating of the cable connected to the fuse terminal does not emit smoke.

On the other hand, when a current exceeding the steady current value of the load flows,
The fuse element is made of a low melting point alloy to reduce the fusing temperature.
Set the temperature in the range of 120 ° C to 335 ° C to set the smoke temperature (150 ° C) of the insulation coating of the cable in which the fuse element is used.
(200 ° C. to 200 ° C.) or less, so that smoke from the insulating coating of the cable connected to the fuse terminal can be prevented.

Further, when the stopper is provided with a partition, the melted molten metal is separated and stored by the partition.

〔Example〕

This embodiment will be described below with reference to FIGS. 1 to 3 and also to FIG.

As shown in FIG. 2, a high-current fuse 8 shown in FIG. 1 includes a resin case 6 having an opening at the bottom 7 and a detachable top plate cover 5 for confirmation. The element 4 housed in 6 is made up of a stopper 9 fitted to the element 4 and closing the bottom 7 of the case 6.

The same resin case as that of the conventional example is used for the resin cases 5 and 6.

The element 4 is composed of a fuse block 2 having the fuse element 2 provided in each of the two heat storage blocks 1 as a block body, and a fuse terminal 3 attached to each of the heat storage blocks 1.

The fuse block 2 is a block body having a sufficient thickness, and therefore has a larger cross-sectional area than a conventional plate-shaped fuse element.

The fuse block 2 and the heat storage block 1 are mainly made of a Sn-Pb alloy, a Sn-Bi alloy, a Sn-Pb alloy, or a low-melting material obtained by adding an additive such as Cd, In, or Sb to a Sn-Bi alloy. And fuse temperature of fuse block 2 to 12
Between 0 ° C. and 339 ° C., the smoke temperature of the insulating coating of the connecting wires used is determined, for example, by the type of plasticizer. 150
The temperature is set at about ℃ to 200 ℃.

The heat storage block 1 is cast integrally with the fuse block 2 so as to have a larger volume than the fuse block 2. For this reason, the heat generation of the fuse block 2 is smoothly transmitted to the heat storage block 1, and the temperature rise of the fuse block 2 is slow-blown by the heat storage block 1 having a larger heat capacity than the fuse block 2.

This slow blow is, as a recommendation, to prevent the fuse block 2 from being blown by an instantaneous transient large current, but by a large current flowing for a certain period of time. Has a time constant and is a characteristic optimal for protection of, for example, a starter motor or a lamp load of an automobile having a large starting current.

On the other hand, as shown in the figure, one of the L-shaped fuse terminals 3 formed by stamping a metal plate is embedded in the heat storage block 1, and the fuse block 2 and the heat storage block 1 are integrally formed as described above. Due to the heat storage effect of the large heat capacity, the heat conducted to the fuse terminal 3 is reduced.

When the element 4 is housed in the case 6, the other end of the fuse terminal 3 projects out of the case 6, as shown in FIG.

A spur 9 is fitted to the bottom 7 of the case 6 in which the element 4 is housed, and receives a blown fuse to prevent leakage outside the case 6.

As shown in FIG. 3 (a), the stopper 9 is arranged in the center of the melt reservoir 10 in parallel with the heat storage block 1 and the top is the fuse block 2 (fuse element).
Is provided in the vicinity of the partition 11. Therefore, when the fuse block 2 is blown as shown in FIG. 2B, the blown fuses are separated from the left and right melt reservoirs 10 by the partition wall 11.
Accumulates in the center and separates at the center to avoid contact. For this reason,
As shown in FIG. 5, the blow fuse 12 does not form the bridge 13 with the heat storage block 1.

This embodiment is configured as described above.
When a starter motor circuit cable is connected to the fuse terminal 3 of the high current fuse 8 shown in FIG. 1 and the starter switch is turned on to start the starter motor, a large starting current flows through the element 4. However, the fuse block 2 is slow blown by the heat storage block 1 provided integrally. At this time, the fuse block 2 does not melt and the starter motor can be started normally.

On the other hand, for example, when the starter motor is locked during operation and a lock current longer than the starting current flows, the fuse block 2 and the heat storage block 1
The heat stored in the fuse block 2 reaches the fusing temperature of the fuse block 2, and the fuse block 2 is blown as shown in FIG.

Also, even if the fuse blows badly,
The blown fuse 12 is stored separately in the left and right sides, and reliably shuts off the current even if a bridge 13 is formed between the fuse 12 and the heat storage block.

At the time of this fusing, the fuse block 2 and the heat storage block 1
Is a low melting point alloy, so that the fusing temperature can be greatly reduced, and the temperature does not reach the temperature at which the case 6 melts.

Further, the fusing temperature is lower than the fuming temperature of the cable coating.
Since the heat conducted to the fuse block 2 is reduced by the heat storage effect of the heat storage block 1 having a larger volume than the fuse block 2, the cable does not emit smoke.

〔effect〕

Since the present invention is configured as described above, the fusing area temperature, which is a drawback of the conventional high-current fuse, is reduced, and the case is melted due to prolonged heat generation in a high-temperature state in the fusing area. Smoking can be prevented.

Further, the provision of the stopper can prevent re-energization by the bridge of the blown fuse, so that the safety is high. Therefore, it is optimal to use the fuse for a large current in, for example, a starter motor circuit for a vehicle.

[Brief description of the drawings]

1 to 3 show an embodiment of a high current fuse according to the present invention. FIG. 1 is a perspective view, FIG. 2 is an exploded perspective view, FIG. 3 is an operation view, and FIG. FIG. 5 is an operation diagram when a fuse is blown, FIG. 5 is an operation diagram when an element of the element heat storage element is made of a low melting point alloy, and FIG. 6 is a perspective view and an exploded perspective view of a conventional example where the element is made of a low melting point alloy. FIG. 7 and FIG. 7 are a perspective view and an exploded perspective view of a conventional example constituted by a plate-like element. DESCRIPTION OF SYMBOLS 1 ... Regenerator block, 2 ... Fuse element (fuse block), 3 ... Fuse terminal, 4 ... Element, 6 ... Resin case, 8 ... Fuse for large current, 9
... stopper, 11 ... partition wall.

Claims (3)

(57) [Scope of request for utility model registration] 1. A fuse element 2 is provided between a pair of heat storage blocks 1 each having a terminal 3 to which an electric wire cable is connected to form an element 4. The element 4 is housed in a resin case 6, and the terminal 3 is In a large current fuse 8 projecting out of the case 6 and provided with a stopper 9 for storing a molten material below the fuse element 4, the element 2 is formed into a block body integrally formed of molten metal, and each heat storage element is provided. The volume of the block 1 is made larger than the volume of the fuse element 2, and the element 4 is formed of a Sn-Pb alloy, a Sn-Bi alloy, or a low-melting alloy obtained by adding an additive to a Sn-Bi alloy. And the fusing temperature of the fuse element 2 is set to 120 ° C to 335 ° C.
Set within the range of ° C., the smoke temperature of the insulation coating of the cable in which the fuse element 2 is used (150 ° C. to 200 ° C.)
A fuse 8 for a large current, which is blown below. 2. A partition wall 11 parallel to the heat storage block 1 is provided on the upper surface of the melt reservoir 10 of the stopper 9, and the top of the partition wall 11 is formed close to the fuse element 2. The high-current fuse according to claim 1. 3. A high-current fuse according to claim 1, wherein said high-current fuse is used in a starter motor circuit for a vehicle.