JP2002246204A - Wire wound resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire wound resistor which is very stable when it is mounted and equipped with a joint of improved stability between a winding and a cap. SOLUTION: A resistive winding 13 is provided on an insulating cylindrical core 11, and a metal cap 21 is fixed to each end of the cylindrical core 11 to serve as the leading electrodes of the winding 13. A thin-walled part 21b is provided to the side of the metal cap 21 facing the winding 13, and the end 13b of the winding 13 is connected to the cap 21 as being fixed to the thin- walled part 21b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistor winding provided with a resistor winding on an insulating cylindrical core, and caps serving as lead electrodes of the winding fitted to both ends of the cylindrical core. The present invention relates to a wire wound resistor whose part is covered with an exterior resin.

[0002]

2. Description of the Related Art Wire wound resistors have a relatively large power capacity, and have been widely used for applications such as resistors connected to a power supply since ancient times. FIG. 4 schematically shows the structure of a conventional wound resistor. A resistor winding 13 is wound around an insulating cylindrical core 11 of ceramics or the like, and is connected and fixed to metal caps 15 with lead terminals disposed at both ends of the cylindrical core 11. Here, metal caps 15, 15
Are fitted to both ends of the insulating cylindrical core and serve as extraction electrodes of the resistor winding. The resistor winding 13 between the caps 15 on both sides is covered and protected by an exterior resin 17.

In such a conventional wound resistor, as shown in FIG. 5, the end 13a of the winding 13 is fixed to the vicinity of the winding-side end 15a of the cap 15 by welding. Therefore, assuming that a leadless winding resistor using only a metal cap without a lead terminal as an extraction electrode is used, the resistor winding and the joint to the cap are protected and covered with the exterior resin 17. In some cases, a bulge 17a may occur in the exterior resin at the joint. For this reason, there has been a problem that mounting failure due to mechanical stress, disconnection or the like occurs.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has a high stability at the time of mounting and an improved winding stability of the connection between the winding and the cap. An object is to provide a wire resistor.

[0005]

According to the present invention, there is provided a winding resistor comprising:
In a winding resistor in which a resistor winding is provided on an insulating cylindrical core and metal caps serving as extraction electrodes of the winding are fitted to both ends of the cylindrical core, * a thin wall is provided on the winding side of the cap. And an end portion of the winding is fixed to the thin portion and connected to the cap.

Here, the thickness of the thick portion of the cap is
The thickness of the thin portion of the cap is larger than the sum of the outer diameter of the windings.

According to the present invention described above, since the lead-out terminal of the winding is fixed to the thin portion of the metal cap and the winding is connected to the cap, even if the connection portion is covered with the exterior resin, that portion is also provided. No swelling occurs. Therefore, stability at the time of mounting is high, and problems such as disconnection due to mechanical stress do not occur.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a winding resistor according to an embodiment of the present invention. This wire wound resistor is a leadless wire wound resistor having no lead terminal, and has high pulse withstand capability and power capacity. A resistor winding 13 is wound around an insulating cylindrical core 11 made of ceramics or glass or resin,
At both ends, metal caps 21 serving as winding lead electrodes are arranged. The connection between the winding 13 and the cap 21 and the winding are covered with the exterior resin 17 and protected. Here, the cap 21 has a thin portion 21b, and the end portion 13b of the winding 13 is fixed to the outer peripheral surface of the thin portion by welding. For this reason, the thickness of the thin portion 21b is designed so that the welded connection portion is smaller than the outer shape of the thick portion 21a of the cap. Does not occur.

FIG. 2 shows the details of the connection between the cap and the winding, and FIG. 3 shows an example of the configuration of the cap.

As shown in FIG.
Is fixed to the outer peripheral surface of the thin portion 21b of the cap 21 by welding. Here, the thick portion 21a of the cap 21
Is about 0.3 mm, and the thickness of the thin portion 21b is about 0.1 mm. On the other hand, the wire diameter of the winding 13 is about 0.1 mm, and the exterior resin 17 is applied so as to have a diameter slightly smaller than the same diameter as the thick part of the cap. Therefore, even if the end portion 13b of the winding is fixed to the thin portion 21b by welding, the total thickness thereof is about 0.2 mm and is embedded in the exterior resin 17. Therefore, the exterior resin 17
No swelling due to the connection between the cap and the winding occurs.

As described above, according to the winding resistor of the present invention,
The outer peripheral surface of the exterior resin 17 is uniformly and smoothly formed with a diameter slightly smaller than the outer diameter of the thick portion of the cap. Therefore, when mounting on a circuit board or the like, surface mounting using a metal cap as an electrode becomes possible. Further, since there is no raised portion of the exterior resin caused by the connection portion unlike the related art, stable mounting can be performed without causing troubles such as solderability due to the raised portion. Also,
The presence of the conventional raised portion causes mechanical stress on the winding connection portion due to contact with the circuit board surface during mounting, but as described above, the raised portion in the wound resistor of the present invention does not Such stress does not occur because it does not exist. Therefore, it is possible to prevent an accident such as disconnection during mounting or subsequent use.

[0013]

In general, according to the present invention, there is provided a leadless winding resistor having high mounting stability and mounting reliability, high pulse withstand capability and high power capacity.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a winding resistor according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing the vicinity of a connection portion between a cap and a winding in FIG. 1;

FIG. 3 is a perspective view showing a structural example of a cap.

FIG. 4 is a perspective view showing a conventional wound resistor.

5 is an enlarged sectional view showing the vicinity of a connection between a cap and a winding in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Cylindrical core 13 Winding 13b Winding end part 15, 21 Cap 17 Exterior resin 21a Cap thick part 21b Cap thin part

Claims (2)

[Claims] 1. An insulating cylindrical core provided with a resistor winding,
In a winding resistor in which a metal cap serving as an extraction electrode of the winding is fitted to both ends of the cylindrical core, a thin portion is provided on the winding side of the cap, and the thin portion has an end portion of the winding. A wire wound resistor, wherein the wire is fixed and connected to the cap. 2. The wound resistor according to claim 1, wherein the thickness of the thick portion of the cap is larger than the sum of the thickness of the thin portion of the cap and the outer diameter of the winding.