JPS6348081Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a resistor that is integrated with a temperature fuse using an inorganic material such as cement.

Among the electrical elements in an electrical circuit, the resistor is the element that is most likely to generate heat due to abnormal current in the circuit.To prevent fires caused by abnormal current in the electrical circuit,
It is effective to attach a temperature fuse to the resistor.

In this case, since the heat transfer characteristics between the resistor and the temperature fuse depend on the attachment state of the temperature fuse, the resistor and the temperature fuse are arranged at a predetermined interval, and they are connected to each other by cement, etc. A resistor with a temperature fuse has been proposed which is integrated with an inorganic material to stabilize the heat transfer characteristics.

However, according to the experience of the inventors of the present invention, there are considerable variations in the heat transfer characteristics of the temperature fuse-equipped resistors manufactured as described above. The main reason for this is that in conventional resistors (wound resistors), the cap-shaped terminal 1'
There is a step 3' between the end of the core 2' (made of porcelain) and a gap between this step 3' and the wound resistance wire 4'.
g' exists, and this gap g' may or may not be filled with the cement. Therefore, if the gap is unfilled, the gap will generate abnormal heat in spots due to the high thermal resistance of the air existing in the gap, and the gap will be in an unfilled state and a filled state. There are differences in the heat generation state of the resistor under abnormal current depending on the case, and as a result, a difference also occurs in the state of heat transfer to the temperature fuse.

Therefore, in order to commercialize the temperature fuse resistor, it is necessary to modify the resistor in such a way that the above-mentioned disadvantages can be eliminated.

The resistor according to the present invention has been devised in view of the above-mentioned points, and has small diameter parts provided at both ends of a cylindrical heat-resistant core, and each of these small diameter parts has an outer diameter that is the same as the outer diameter of the core. A cap-shaped terminal is fitted into the core, a resistance wire is wound around the core, and each end of the resistance wire is joined to the outer peripheral surface of each cap-shaped terminal.

The present invention will be explained below with reference to the drawings.

FIG. 2 shows a wire-wound resistor according to the present invention.

In FIG. 2, reference numeral 1 denotes a cylindrical heat-resistant core, for example, a porcelain bar, and small-diameter portions 11, 11 are provided at both ends. Reference numerals 12 and 12 indicate end faces of the small diameter portion. 2 is a cap-shaped terminal having a lead conductor 21, which is fitted into the small diameter portion 11 at each end of the core;
The cap end and the end face of the small diameter portion are butted together. The outer diameter of the cap-shaped terminal 2 is made equal to the outer diameter of the core 1, and therefore, the outer circumferential surface of the cap-shaped terminals 2, 2 and the outer circumferential surface of the core 1 are flush with each other. 3 is a resistance wire wound on the core 1, and each end 31, 3
1 is joined to the outer peripheral surface of each cap-shaped terminal 2, 2 by welding or the like. The wound resistance wire is thus in complete contact with the cap-shaped terminal as well as with the porcelain core.

FIG. 3A shows a resistor with a temperature fuse using the resistor according to the present invention.

In FIG. 3A, A is a porcelain case, B is a resistor of the present invention, C is a temperature fuse, and D is cement filled in case A. In this resistor with a temperature fuse, the outer circumferential surface of the cap-shaped terminal 2 of the resistor B and the outer circumferential surface of the magnetic core 1 are flush with each other, and there is a gap between them at g' in FIG. Since there is no level difference as shown and the resistance wire end 31 is in contact with the cap-shaped terminal 2 and the core 1, it is possible to eliminate the unfilled portion of cement that causes the hot spot, and the temperature fuse between the resistor B and the temperature fuse can be eliminated. The heat transfer characteristics between C and C can be made constant without variation.

However, as shown in FIG. 3B showing the bb section of FIG. 3A and FIG. 3C showing the cc section of FIG. An inside corner e occurs between the wound resistance wire 3 and the outer peripheral surface of the porcelain core 1, and this corner may not be filled with cement. conducts easily to the cap-shaped terminal 2 and the magnetic core 1 that are in contact with the resistance wire 3 because their contact surfaces have low thermal contact resistance, and the void e that is not filled with cement mostly participates as a thermal resistor. As a result, the above cement-free areas are
It does not substantially affect the heat transfer properties described above.

As mentioned above, the present invention is extremely useful as a resistor for a temperature fuse resistor to make the heat transfer characteristics of the temperature fuse resistor constant without variation, and contributes to the industrialization of temperature fuse resistors. However, it is large.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a conventional resistor, Fig. 2 is an explanatory diagram showing a resistor according to the present invention, and Fig. 3A is an explanatory diagram showing a resistor with a temperature fuse using the resistor according to the present invention. Figure 3B and Figure 3C are explanatory diagrams of b-b cross-section and c-c in Figure 3A, respectively.
It is an explanatory view of c cross section. In the figure, 1 is a cylindrical heat-resistant core, 11, 11
2 is a small diameter portion, 2, 2 is a cap-shaped terminal, and 3 is a wound resistance wire.

Claims (1)

[Scope of utility model registration request] Small diameter parts are provided at both ends of the cylindrical heat-resistant core, cap-shaped terminals having the same outer diameter as the core are fitted into each of these small diameter parts, and a resistance wire is wound on the core to connect the resistor. A resistor characterized in that each end of the wire is joined to the outer peripheral surface of each of the cap-shaped terminals.