Surge-resistant wire-wound resistor and method for manufacturing same

Abstract

The present invention relates to a surge-resistant wire-wound resistor and a manufacturing method thereof, wherein soldering points, at which a cap at each end of the wire-wound resistor is soldered, are electroplated with an electroplated metal layer to significantly improve the reliability of soldering points. The surge-resistant wire-wound resistor comprises a ceramic rod; one or more than one wound metal wire; a first cap and a second cap; a first lead wire and a second lead wire, wherein the first cap and the second cap are respectively electroplated to have a first cap electroplated layer and a second cap electroplated layer.

Claims

1. A surge-resistant wire-wound resistor, comprising: a ceramic rod which has a first end and a second end; one or more than one wound metal wire which has a wire head and a wire tail and is helically wound around the ceramic rod from the first end to the second end; a first cap and a second cap which are respectively disposed along an axis of the ceramic rod and extending outwardly from the first end and the second end, wherein the wire head and the wire tail are respectively soldered onto surfaces of the first cap and the second cap at the first cap and the second cap, and the first cap and the second cap are then respectively electroplated with a first cap electroplated layer and a second cap electroplated layer; a first insulating layer which is disposed on a surface of the ceramic rod and covers surfaces of the ceramic rod and the wound metal wire; a first lead wire and a second lead wire which are respectively disposed along an axially extended line of the ceramic rod and extending outwardly from the first cap and the second cap; and a second insulating layer which is disposed on and covers a surface of the first insulating layer and surfaces of the first cap electroplated layer and the second cap electroplated layer.

2. The surge-resistant wire-wound resistor of claim 1, wherein the first cap electroplated layer is selected in material from the group consisting of tin, copper, iron, silver, nickel and alloys thereof.

3. The surge-resistant wire-wound resistor of claim 2, wherein the thickness of the first cap electroplated layer is from 1 m to 10 m.

4. The surge-resistant wire-wound resistor of claim 1, wherein the second cap electroplated layer is in material selected from the group consisting of tin, copper, iron, silver, nickel and alloys thereof.

5. The surge-resistant wire-wound resistor of claim 4, wherein the thickness of the second cap electroplated layer is from 1 m to 10 m.

6. The surge-resistant wire-wound resistor of claim 1, wherein a material of the first insulating layer is epoxy resin, nonflammable silicone paint or enamel paint.

7. The surge-resistant wire-wound resistor of claim 1, wherein a material of the second insulating layer is epoxy resin, nonflammable silicone paint or enamel paint.

8. A manufacturing method for a surge-resistant wire-wound resistor, comprising: providing a ceramic rod; mounting a first cap and a second cap respectively on a first end and a second end of the ceramic rod; winding a wound metal wire around the circumference of the ceramic rod; soldering two ends of the wound metal wire onto the first cap and the second cap; coating a first insulating layer on surrounding of the ceramic rod; electroplating a cap electroplated layer respectively on surfaces of the first cap and the second cap; connecting a first lead wire and a second lead wire to an axially extended line of the ceramic rod and extending the first and second lead wires outwardly from the first cap and the second cap; and coating a second insulating layer on a surface of the first insulating layer and surfaces of the first cap electroplated layer and the second cap electroplated layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram showing that a conventional wire-wound resistor is soldered obliquely.

(2) FIG. 2 is a side view diagram of a conventional wire-wound resistor.

(3) FIG. 3A is a side view diagram of the first embodiment of a wire-wound resistor of the present invention.

(4) FIG. 3B is a side view diagram of the second embodiment of a wire-wound resistor of the present invention.

(5) FIG. 4A is a diagram illustrating a cross section of the first embodiment of a wire-wound resistor of the present invention.

(6) FIG. 4B is a diagram illustrating a cross section of the second embodiment of a wire-wound resistor of the present invention.

(7) FIG. 5 is a schematic diagram showing a soldering point of a wire-wound resistor of the present invention.

EXAMPLES

(8) As shown in FIG. 3A, FIG. 3B, FIG. 4A and FIG. 4B, according to the first example of the present invention (the MELF type of wire-wound resistor), the present invention provided a surge-resistant wire-wound resistor 20, comprising:

(9) a ceramic rod 21 which had a first end 211 and a second end 212;

(10) one or more than one wound metal wire 23 which had a wire head 231 and a wire tail 232 and was helically wound around the ceramic rod from the first end 211 to the second end 212;

(11) a first cap 221 and a second cap 222 which were respectively disposed along an axis of the ceramic rod 21 and extending outwardly from the first end 211 and the second end 212, wherein the wire head 231 and the wire tail 232 were respectively soldered on the surfaces of the first cap 221 and the second cap 222 at the first cap 221 and the second cap 222, and the first cap 221 and the second cap 222 were respectively electroplated with a first cap electroplated layer 2211 on the surface of the first cap 221 and a second cap electroplated layer 2221 on the surface of the second cap 222; and
a first insulating layer 2111 which was disposed on the surface of the ceramic rod 21 and covered the surfaces of the ceramic rod 21 and the wound metal wire 23.

(12) According to the second example of the present invention (a type of the wire-wound resistor with winding wires), the present invention provided a surge-resistant wire-wound resistor 420, comprising:

(13) a ceramic rod 421 which had a first end 4211 and a second end 4212; one or more than one wound metal wire 423 which had a wire head 4231 and a wire tail 4232 and was helically wound around the ceramic rod 421 from the first end 4211 to the second end 4212;

(14) a first cap 4221 and a second cap 4222 which were respectively disposed along an axis of the ceramic rod 421 and extending outwardly from the first end 4211 and the second end 4212, wherein the wire head 4231 and the wire tail 4232 were respectively soldered on the surfaces of the first cap 4221 and the second cap 4222 at the first cap 4221 and the second cap 4222, and the first cap 4221 and the second cap 4222 were respectively electroplated with a first cap electroplated layer 42211 on the surface of the first cap 4221 and a second cap electroplated layer 42221 on the surface of the second cap 4222;
a first insulating layer 42111 which was disposed on the surface of the ceramic rod 421 and covered the surfaces of the ceramic rod 421 and the wound metal wire 423;
a first lead wire 4241 and a second lead wire 4242 which were respectively disposed along an extended line of the axle center 4213 of the ceramic rod 421 and extending outwardly from the first cap 4221 and the second cap 4222; and
a second insulating layer which was disposed on and covered the surface of the first insulating layer 42111 and the surfaces of the first cap 4221 and the second cap 4222.

(15) The ceramic rod 21, 421 of the present invention was made of, but not limited to, insulating materials. Any insulating cylinders which could achieve the goal of the present invention could be used, for example, a white ceramic rod or a glass fiber cylinder.

(16) The first cap 221, 4221 and the second cap 222, 4222 were mounted on two ends of the ceramic rod 21, 421. Materials of the first cap 221, 4221 and the second cap 222, 4222 could be, but not limited to, metals such as iron, steel, aluminum, copper, or other alloys or graphite materials. Any materials which could fulfill the function of the cap could be used.

(17) As shown in FIG. 3A and FIG. 3B, the wire head 231, 4231 was soldered onto the first cap 221, 4221 at a wire-head soldering point 2311, 42311; the wire tail 232, 4232 was soldered onto the second cap 222, 4222 at a wire-tail soldering point 2321, 42321.

(18) As shown in 4A and FIG. 4B, the first cap electroplated layer 2211, 42211 and the second cap electroplated layer 2221, 42221 of the present invention were respectively formed on the first cap 221, 4221 and the second cap 222, 4222 by using an industrial electroplating process, wherein the electroplated layer of the first cap electroplated layer 2211, 42211 and the second cap electroplated layer 2221, 42221 were in material selected from the group consisting of, but not limited to, tin, copper, iron, silver, nickel and alloys thereof.

(19) As shown in FIG. 5, as to the wire-wound resistor of the present invention, the wire tail 332 of the wound metal wire 33 wound around the ceramic rod 31 was soldered onto the surface of the cap 322, and a cap electroplated layer 3221 was formed on the soldering point 3321.

(20) As shown in FIG. 3A and FIG. 4A, according to the first example of the present invention, the present invention provided a manufacturing method for a surge-resistant wire-wound resistor, comprising the steps of:

(21) providing a ceramic rod 21;

(22) mounting a first cap 221 and a second cap 222 respectively on a first end 211 and a second end 212 of the ceramic rod 21;

(23) winding a wound metal wire 23 around the circumference of the ceramic rod 21;

(24) soldering two ends of the wound metal wire 23 onto the first cap 221 and the second cap 222;

(25) coating a first insulating layer 2111 on surrounding of the ceramic rod 21; and

(26) electroplating surfaces of the first cap 221 and the second cap 222 to form a cap electroplated layer 2211 and a cap electroplated layer 2221, respectively.

(27) As shown in FIG. 3B and FIG. 4B, according to the second example of the present invention, the present invention provided a manufacturing method for a surge-resistant wire-wound resistor, comprising:

(28) providing a ceramic rod 421;

(29) winding a wound metal wire 423 around the circumference of the ceramic rod 421;

(30) mounting a first cap 4221 and a second cap 4222 respectively on a first end 4211 and a second end 4212 of the ceramic rod 421;

(31) soldering two ends of the wound metal wire 423 onto the first cap 4221 and the second cap 4222;

(32) coating a first insulating layer 42111 on surrounding of the ceramic rod;

(33) electroplating surfaces of the first cap 4221 and the second cap 4222 respectively to form a cap electroplated layer 42211 and a cap electroplated layer 42221;

(34) connecting a first lead wire 4241 and a second lead wire 4242 to an extended line of the axial center of the ceramic rod 421 and extending them outwardly from the first cap 4221 and the second cap 4222; and

(35) coating a second insulating layer 42112 on a surface of the first insulating layer 42111 and surfaces of the cap electroplated layer 42211 and the cap electroplated layer 42221.

(36) In the present invention, because the first cap and the second cap were respectively electroplated to have a cap electroplated layer, the strength of the soldering points was increased, the failure rate was decreased, and the reliability of the soldering points was further improved. Therefore, the failure rate of the surge-resistant soldering point of the wire-wound resistor provided by the present invention was less than 0.1 ppm.

(37) The wire-wound resistor provided by the present invention could be used not only in surge-resistant circuits, but also in spark plug covers for the motor vehicle and motorcycle industry and ignition systems for automobiles.

(38) The structures and examples aforementioned are illustrated for fully realizing the present invention and should not be construed to limit the scope of the invention. One skilled in the art may modify and vary the examples without departing from the spirit and scope of the present invention.