JP4332391B2 - Manufacturing method of resistors with lead terminals - Google Patents

Description

The present invention relates to a method for manufacturing a vertically mounted resistor with a lead terminal in which a resistor body is held on a mounting surface in a standing posture.

  Resistors with lead terminals with lead terminals protruding from both ends of the resistor body may be mounted sideways on the circuit board. However, in order to increase the mounting density and heat dissipation effect, the resistors are raised on the circuit board. Often implemented in a posture. FIG. 9 is a front view showing a conventional example of such a vertically placed resistor with lead terminals. A resistor 1 with lead terminals shown in FIG. 1 includes a substantially cylindrical resistor body 2 and a pair of lead terminals 3 and 4 projecting from both ends of the resistor body 2. Of the lead terminals 3 and 4 made of wire, one lead terminal 3 is short, but the other lead terminal 4 is longer than that and has a base end bent into a substantially U shape. When such a resistor 1 with lead terminals is mounted on a circuit board (not shown), the tips of the pair of lead terminals 3 and 4 are respectively inserted into corresponding lead mounting holes of the circuit board and soldered to lands. The resistor body 2 is held on the mounting surface in an upright posture. In addition, although this kind of resistor 1 with a lead terminal may be directly mounted on a circuit board, in order to improve self-supporting strength, it may be mounted together with a holder (for example, refer patent document 1). ).

When manufacturing such a conventional resistor 1 with a lead terminal, first, as shown in FIG. 10 (a), a carbon film 6 is provided on the surface of an insulator 5 made of an insulating material such as ceramic to form a resistor element 7. Form. Next, as shown in FIG. 10 (b), after attaching electrode caps 8 to both ends of the resistor element 7, as shown in FIG. 10 (c), a spiral groove 6a is provided in the carbon coating 6 for resistance. By adjusting the value, an unpainted resistor 2a set to a desired resistance value is obtained. Next, as shown in FIG. 10 (d), wire rods 9 and 10 extending in the axial direction of the unpainted resistor 2 a are welded to the end faces of the electrode caps 8. Thereafter, as shown in FIG. 10 (e), the resistor body 2 is formed by painting the protective film 2b on the unpainted resistor 2a. Although not shown in the drawing, a seal or color code indicating a set resistance value or the like is displayed on the protective film 2b, and then one wire 9 is cut to form the short first lead terminal 3, and the other The wire rod 10 is formed into a folded shape to form the second lead terminal 4, thereby completing the resistor 1 with a lead terminal shown in FIG.
Japanese Utility Model Publication No. 1-1115291 (page 4, FIG. 2)

  By the way, the conventional resistor 1 with lead terminals as shown in FIG. 9 has no difference in the basic configuration even if the size of the resistor body 2 is different. There is a merit that a resistor can be manufactured, and this is a major factor for realizing cost reduction. For example, in the manufacturing process shown in FIG. 10 (d), an expensive machine is necessary to align the unpainted resistor 2a and the wires 9 and 10 and perform highly reliable welding efficiently. If different machines are prepared according to the size of the resistor body 2 (unpainted resistor 2a), enormous capital investment will be required. Since the wire rods 9 and 10 are chucked and welded using a machine, a wide variety of resistors with lead terminals can be manufactured at a very low cost.

  However, in the resistor 1 with a lead terminal manufactured using such a general-purpose machine, the lengths of the wires 9 and 10 are standardized. Therefore, the longitudinal dimension (axial dimension) of the resistor body 2 is somewhat long. As a result, the length of the second lead terminal 4 formed into a folded shape is insufficient. That is, the second lead terminal 4 includes a base end portion that is folded back in a substantially U shape, an intermediate portion that extends along the resistor body 2, and a distal end portion that extends along the first lead terminal 3. Therefore, when the resistor main body 2 is long and the intermediate portion becomes long, the tip portion becomes relatively short, and when the tip portion becomes excessively short, the resistor 1 with lead terminals cannot be mounted. Therefore, the conventional resistor 1 with a lead terminal that can be manufactured at low cost using a general-purpose machine has a problem that it cannot cope with the necessity of increasing the length of the resistor body 2.

The present invention has such has been made in view of the circumstances of prior art, and its object is to provide a vertical-type method for producing inexpensive with lead terminal resistor to accommodate elongate of resistor body There is.

To achieve the above object, the present invention provides a resistor body production method with the lead terminal resistor that is implemented by inserting the lead terminals to the lead mounting hole of the circuit board so that the standing posture, the resistor A wire welding process for welding a wire extending in the axial direction of the resistor body to both ends of the body, and a short lead for forming a short first lead terminal by cutting one of the wires after the wire welding process The extension wire is formed by abutting one end face of the extension wire cut and removed in the short lead forming step with the distal end surface of the other wire after the forming step and the wire welding step and performing cold pressure welding. And a cold pressure welding process for forming a long lead formed by adding the first lead to the other wire, and forming a second lead terminal formed into a folded shape from the long lead.

In such a method of manufacturing a resistor with a lead terminal, a cold welding process of forming a long lead by adding an extension wire to the tip of a wire welded to one end of the resistor body by a cold welding method Since the second lead terminal having a folded shape is formed from the long lead, the second lead terminal having a desired length can be easily formed. In addition, since the wire material cut and removed in the short lead forming process is used as an extension wire in the cold welding process, the wire can be used effectively, saving material costs, and shortening the cold welding process. It can be efficiently performed continuously with the forming step. In addition, since each other process can be performed using a general purpose machine, a new capital investment is unnecessary. Therefore, even if the length required for the second lead terminal is increased with the increase in the length of the resistor body, it is possible to cope with a low cost only by a minimum cost increase.

In the manufacturing method of the longitudinally mounted resistor with lead terminals according to the present invention, a long lead is formed by adding an extension wire to the tip of the wire welded to one end of the resistor body by a cold welding method. Since the second lead terminal having the folded shape is formed from the long lead, the second lead terminal having a desired length can be easily formed. In addition, the wire material cut and removed in the short lead forming process is used as an extension wire in the cold welding process, so that the wire can be used effectively and material costs can be saved, and the cold welding process can be shortened. It can be efficiently performed continuously with the forming step. Therefore, even if the length required for the second lead terminal is increased with the increase in the length of the resistor main body, it is possible to cope with the cost with a minimum cost increase .

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a longitudinally mounted resistor having lead terminals according to an embodiment of the present invention, and FIG. FIG. 3 is an explanatory diagram showing in detail the cold welding process during the manufacturing process, FIG. 4 is an enlarged view of the main part of FIG. 3, and FIG. 5 is an enlarged view of the pressure bonding surface of the die shown in FIG. 6 is a sectional view taken along line AA in FIG. 5, FIG. 7 is a sectional view taken along line BB in FIG. 5, and FIG. 8 is a side view taken along line CC in FIG.

  A resistor 11 with lead terminals shown in FIG. 1 is composed of a resistor body 12 having a substantially cylindrical shape and a pair of lead terminals 13 and 14 projecting from both ends of the resistor body 12. One lead terminal 13 of the lead terminals 13 and 14 made of wire is short, but the other lead terminal 14 formed into a folded shape is greatly lengthened by cold welding described later. It has been extended. The long lead terminal 14 includes a base end portion 14 a folded back in a substantially U shape, an intermediate portion 14 b extending along the resistor body 12, and a distal end extending along the first lead terminal 13. It consists of a part 14c, and a part of the intermediate part 14b is a joint part P formed by cold welding. When the resistor 11 with lead terminals is mounted on a circuit board (not shown), the tip portion of the lead terminal 13 and the tip portion 14c of the lead terminal 14 are respectively connected to the corresponding lead mounting holes of the circuit board. The resistor body 12 is inserted and soldered to the land so that the resistor body 12 is held on the mounting surface in a standing posture.

  In the manufacturing method of the resistor 11 with the lead terminal configured as described above, the steps until the resistor main body 12 is formed by coating the protective film on the unpainted resistor having the wire projecting at both ends are the same as the conventional method described above. This is basically the same as the technology (see FIG. 10). That is, a carbon film is first provided on the surface of an insulator made of an insulating material such as ceramic to form a resistor element, electrode caps are attached to both ends of the resistor element, and then a spiral groove is provided in the carbon film. An unpainted resistor set to a desired resistance value is obtained by adjusting the resistance value. And after welding the wire which extends in the axial direction of an unpainted resistor to the end surface of each electrode cap, the resistor main body 12 is formed by coating a protective film on the unpainted resistor. Then, a stamp or color code indicating a set resistance value or the like is displayed on the protective film, and the state shown in FIG. That is, in FIG. 2A, wire members 15 and 16 extending in the axial direction are welded to both ends of the resistor main body 12, and the surface (protective film) of the resistor main body 12 is not shown. A seal or color code is displayed.

  The next manufacturing process is a short lead forming process shown in FIG. 2 (b), in which one of the wires 15 in FIG. 2 (a) is cut at an appropriate position to make a short first lead having a predetermined dimension. Terminal 13 is formed. At this time, the cut-and-removed portion 15a of the wire 15 indicated by a chain line is used as an extension wire in a subsequent cold pressing process. That is, in the next cold welding process, as shown in FIG. 2C, the second lead terminal 14 is obtained by adding the extension wire 15a to the tip of the other wire 16 by a known cold welding method. A long lead 17 is formed.

  The work procedure of the cold welding process will be described. First, as shown in FIGS. 3A and 4A, the wire 16 projecting from one end of the resistor body 12 and the wire 15 are cut. The extension wire 15a, which is the removed portion, is arranged in a straight line inside the die 20. This die 20 is configured by combining four blocks 21 to 24 whose shapes of the pressure bonding surfaces 21a to 24a are symmetrical to each other, and a semicircle is formed at the center of one side edge of each of the pressure bonding surfaces 21a to 24a. A ridge-shaped bulging portion 25 is formed, and a concave groove 26 that extends in a straight line to the chucking surfaces 21 b to 24 b adjacent to the pressure bonding surfaces 21 a to 24 a and reaches the top of the bulging portion 25. It is formed (see FIGS. 5 to 8). That is, the wire 16 is disposed between the opposing concave grooves 26 of the blocks 21 and 22, and the extension wire 15 a is disposed between the opposing concave grooves 26 of the blocks 23 and 24. By bringing the end faces into contact with each other, the state shown in FIGS. 3 (a) and 4 (a) is obtained.

  Then, while the end faces of both wires 16 and 15a are abutted with each other, as shown in FIGS. 3 (b) and 4 (b), the spacing between the blocks 21 and 22 is narrowed to oppose each other. The wire 16 is chucked by 22b, and the extension wire 15a is chucked by the opposing chucking surfaces 23b and 24b with the interval between the blocks 23 and 24 narrowed. Thereafter, as shown in FIGS. 3 (c) and 4 (c), pressure is applied in such a direction as to narrow the distance between the blocks 21, 22 and the blocks 23, 24, and the two wires 16, 15a are brought into contact with each other. A long lead 17 formed by adding the wire 15a for extension to the wire 16 is formed by performing cold pressure welding in which the portions are crimped and joined. Note that, as a result of such cold welding, burrs 18 as shown in FIG. 2C and FIG. 4D are generated at the joints P of the two wires 16 and 15a. There is no problem because a space for the burr 18 to escape is defined in the surrounding area. Thereafter, as shown in FIGS. 3D and 4D, the pressurization and chucking by the blocks 21 to 24 are released, and the long lead 17 is removed from the die 20.

  When the cold welding process is completed in this way, a burr removing process for removing the burr 18 remaining on the long lead 17 for the second lead terminal 14 is performed, and the state shown in FIG. Then, in the next long lead cutting step, the long lead 17 is cut at an appropriate position as shown in FIG. 2E to form the second lead terminal 14 having a desired length. Thereafter, the second lead terminal 14 is formed into a folded shape in the next bending step, and the resistor 11 with lead terminal shown in FIG. 1 is completed.

Thus, the manufacturing method of the resistor 11 with a lead terminal according to the present embodiment is short-sized by projecting the wire members 15 and 16 at both ends of the resistor body 12 and cutting one wire member 15 at an appropriate position. After forming the first lead terminal 13, a long lead 17 is formed by adding an extension wire 15a, which is a cut and removed portion of the wire 15, to the tip of the other wire 16 by cold welding. Since the second lead terminal 14 is formed from the long lead 17, the second lead terminal 14 can be formed to a desired length only by adding a simple cold welding process to a conventional manufacturing process. A general-purpose machine can be used in each process other than the cold pressure welding process. In addition, in this embodiment, the wire rod can be effectively used because the cut and removed portion of the wire rod 15 generated in the short lead forming step is used as the extension wire rod added to the tip of the wire rod 16 in the cold pressure welding step. Thus, the material cost can be saved and the cold welding process can be efficiently performed continuously with the short lead forming process. Therefore, even when the length of the folded second lead terminal 14 has to be increased as the resistor body 12 becomes longer, it is possible to cope with the cost reduction with a minimum cost increase.

It is a front view of the resistor with a lead terminal concerning the example of an embodiment of the present invention. It is manufacturing process explanatory drawing of the resistor shown in FIG. It is explanatory drawing which shows the cold pressure welding process in the manufacturing process of FIG. 2 in detail. It is a principal part enlarged view of FIG. FIG. 4 is an enlarged view of a pressure bonding surface of the die shown in FIG. 3. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is a side view which follows the CC line of FIG. It is a front view of the resistor with a lead terminal which concerns on a prior art example. It is manufacturing process explanatory drawing of the resistor shown in FIG.

DESCRIPTION OF SYMBOLS 11 Resistor with lead terminal 12 Resistor main body 13 1st lead terminal 14 2nd lead terminal 15, 16 Wire material 15a Extension wire material 17 Long lead 20 Dies 21-24 Block 21a-24a Pressure bonding surface 21b-24b Chucking surface

Claims (1)

In the method of manufacturing a resistor with a lead terminal that is mounted by inserting the lead terminal into the lead mounting hole of the circuit board so that the resistor body is in a standing posture,
A wire welding step of welding a wire extending in the axial direction of the resistor body to both ends of the resistor body;
A short lead forming step of forming a short first lead terminal by cutting one of the wires after the wire welding step;
After the wire welding step, one end surface of the extension wire cut and removed in the short lead forming step is brought into contact with the distal end surface of the other wire material, and cold welding is performed, whereby the extension wire material is connected to the other wire material. A cold welding process for forming a long lead formed by adding to the wire,
A method of manufacturing a resistor with a lead terminal, wherein a second lead terminal formed into a folded shape is formed from the long lead.

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