JPH0229652Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an improvement in a resistance temperature fuse.

<Prior art and problems> A temperature fuse element is provided in close proximity to the electrical resistor in terms of heat conduction, and when the electrical resistor reaches a predetermined temperature due to heat generated by electricity, the temperature fuse element is blown to cut off the circuit current. This is known, and the structure in close proximity to the electrical resistor and temperature fuse element is called a so-called resistance temperature fuse.

FIG. 3A shows an example of a known resistance temperature fuse, in which 1' is an inorganic heat-resistant insulating substrate such as ceramics, and 2' is a temperature fuse element (for example, a low melting point alloy foil) provided at one end of the insulating substrate. , 3' is flux, 4a', 4b' are foil conductors provided on an insulating substrate, 5' is a layered electrical resistor provided in the middle of one of the foil conductors 4a', 7' is an insulating overcoat, 6a ′、
6b' is a lead conductor.

In Fig. 3A, if the current applied becomes excessive and the electrical resistor 5' generates heat, this heat is transferred to the fuse element 2', which causes the fuse element 2' to melt and cut off the circuit current. . However, the heat transfer from the electrical resistor 5' to the fuse element 2' is limited to the conductor 4 on the side to which the electrical resistor 5' is connected.
Thermal conduction is mainly through a', and as shown in FIG. 3B, the temperature fuse element fuses near one end 21a' to which this conductor 4a' is connected, and only on one end side. However, the other end 21b' remains fused and is difficult to form into a spherical shape. Therefore, it is not possible to provide a large insulation distance at the fused portion, and it is difficult to ensure reliable interruption.

<Purpose of the invention> The purpose of the invention is to
It is an object of the present invention to provide a resistance temperature fuse which can be spherically shaped on both sides of the fuse and can be shut off reliably.

<Structure of the invention> The resistance-temperature fuse according to the invention includes a fusible metal body provided at one end of an insulating substrate, conductors connected to both ends of the fusible metal body, and conductors connected to both ends of the insulated substrate. In a resistance-temperature fuse in which an electric resistor is provided in the middle of one of the conductors, the thermal conductivity of the portion of the one conductor from the electric resistor to the fusible metal body corresponds to that of the other conductor. This structure is characterized in that the thermal conductivity of the parts is made equal to each other.

<Explanation of Examples> The present invention will be explained below with reference to the drawings.

In FIG. 1, 1 is a heat-resistant insulating substrate;
For example, a ceramic plate can be used.
2 is a temperature fuse element, which uses a low melting point alloy foil. 3 is flux. 4a and 4b are foil-like conductors, which are integrally provided on the insulating substrate 1 and can be formed by etching.
5 is a layered electrical resistor, which is provided in the middle of one conductor 4a. Lead conductors 6a and 6b are connected to each conductor 4a and 4b. 7 is an overcoat insulator. 41a is one conductor portion extending from the electrical resistor 5 to the temperature fuse element 2;
1b is the other conductor portion corresponding to this conductor portion 41a. The reference point of the electrical resistor for these conductor portions is X-
For X-rays, by making the width of one conductor portion 41a smaller than the width of the other conductor portion 41b, the thermal conductivity from the electrical resistor 5 to the temperature fuse element 2 via the conductor portion 41a is reduced. , electrical resistor 5
The thermal conductivity from the temperature fuse element 2 through the insulating substrate portion C and the other conductor portion 41b is approximately equal.

In the above embodiment, as shown in FIG. 2, the length of one conductor portion 41a is
It may be made longer than the length b so that the thermal conductivity of one heat conduction path is approximately equal to the thermal conductivity of the other heat conduction path.

<Effect of the invention> As described above, in the resistance-temperature fuse according to the present invention, since the thermal conductivity from the electrical resistor to both ends of the temperature fuse element can be made almost equal, the temperature fuse element can be melted evenly from both ends. , both sides of the temperature fuse element melting point can be made spherical. Therefore, the insulation distance at the melting point can be increased, and reliable melting can be ensured.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a resistance temperature fuse according to the present invention, Fig. 2 is an explanatory diagram showing another embodiment of the invention, Fig. 3A is an explanatory diagram showing a conventional resistance temperature fuse, and Fig. 3B is an explanatory diagram showing a conventional resistance temperature fuse. FIG. 2 is an explanatory diagram showing the operating state of a conventional resistance temperature fuse. In the figure, 1 is an insulating substrate, 2 is a fusible metal body,
41a is one conductor portion, 41b is the other conductor portion, and 5 is an electric resistor.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A fusible metal body is provided at one end of an insulating substrate, each conductor to be connected to both ends of the fusible metal body is provided on the insulated substrate, and one of these two conductors is provided on the insulating substrate. In a resistance temperature fuse in which an electrical resistor is provided in the middle of one of the conductors, the thermal conductivity of the one conductor section extending from the electrical resistor to the fusible metal body is determined by the thermal conductivity of the other conductor section corresponding to the same section. A resistance temperature fuse characterized by being configured to have a thermal conductivity equal to the thermal conductivity. (2) The temperature fuse according to claim 1 of the utility model registration claim, wherein the width of one of the conductor parts from the electric resistor to the fusible metal body is smaller than the width of the other conductor part corresponding to the same part. . (3) The temperature set forth in claim 1 of the utility model registration claim in which the length of one of the conductor parts from the electric resistor to the fusible metal body is longer than the length of the other conductor part corresponding to the same part. Hughes.