JPH0582002U - Power type surface mount low resistor - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a power type surface mount low resistor which has good solderability, mechanical strength, improved reliability, and is capable of automatic surface mount. [Structure] At least nickel silver, copper / nickel (Cu-N
i), a low-resistive body made of any one of nickel-chromium (Ni-Cr) and a mold resin body having electric insulation property, or at least nickel silver, copper-nickel (Cu-Ni), nickel One of a low resistance body made of chromium (Ni-Cr), a case body having heat resistance and electric insulation, and a filler having heat resistance and heat dissipation and electric insulation. A power type surface mount low resistor characterized by comprising:

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a power type surface mount low resistor which also serves as a low resistance element and an external electrode.

[0002]

[Prior Art]

 A conventional power type surface mount resistor (not shown) for low resistance of this type is, for example, a pair of winding resistors, a metal oxide film resistor, a metal film resistor, or the like formed at either end. Connect the external electrode guided to the outside to the internal electrode or the metal cap using solder or the like, and connect the winding resistor and the solder or the like to the connection part and the part of the external electrode near the connection part. It is known that the above is sealed with a mold resin body.

[0003]

[Problems to be solved by the device]

 However, in the case of these conventional techniques, in any case (not shown) such as a wire wound resistor, a metal oxide film coated resistor, or a metal film resistor, those resistors are not included in the molded resin body. Although it is sealed, it is necessary to electrically connect the external electrodes to the internal electrodes or metal caps formed on those winding resistors and the like. However, since an electrical contact resistance is generated at the connection part between the internal electrode or the metal cap and the external electrode, the accuracy and the yield are likely to decrease. In addition, the mechanical reliability of this connection portion is likely to decrease. Furthermore, as the contact resistance at this connection increases, the (Joule) heat tends to concentrate only on the resistor part that is not the connection part, which causes deterioration of the mold resin body in the resistor part and its peripheral part. There is a problem that it becomes easier and eventually the life of the power type surface mount low resistance device is shortened.

The present invention has been made in view of such a point, and a metal or an alloy is used to obtain a low resistance value, so that the low resistance body and the external electrode are combined and integrated. Therefore, it is mechanically strong, reliability is improved, the manufacturing process can be simplified, automatic mounting is possible, production efficiency is good, the cost is low, and the vicinity of both ends of the resistor / external electrode is led out to the outside. It is sealed with a heat-dissipating and electrically-insulating mold resin body, or the case body is filled with a heat-resistant, heat-dissipating and electrically-insulating filler. It is an object of the present invention to provide a power type surface mount low resistor which can be easily surface mounted.

[0005]

[Means for Solving the Problems]

 The power type surface mount low resistance device of the present invention has a low resistance material of at least nickel silver, copper / nickel (Cu-Ni) or nickel / chromium (Ni-Cr), and electrical insulation. It has heat resistance and electrical insulation with a low-resistivity material consisting of a molded resin body or at least one of nickel silver, copper / nickel (Cu-Ni), and nickel / chromium (Ni-Cr). A power type surface mounted low resistance resistor comprising a case body and a filler having heat resistance, heat dissipation and electric insulation.

[0006]

[Action]

 Since the power type surface mount low resistance device of the present invention serves as both a low resistance body and an external electrode and is integrated, mechanical strength and reliability can be improved. In addition, since the manufacturing process can be simplified and the automatic mounting can be performed, the production efficiency can be improved at low cost. In addition, since the both ends of the low-resistor / external electrode are sealed with a heat-dissipating mold resin body so as to be drawn to the outside, a heat-resisting, heat-dissipating and electrically insulating filler is filled in the case Therefore, automatic surface mounting can be easily performed.

[0007]

【Example】

 Hereinafter, an embodiment of the power type surface mount low resistor of the present invention will be described with reference to the drawings.

Reference numeral 1 is a metal plate, and the metal plate 1 is made of a low resistance metal or alloy such as nickel silver, copper-nickel (Cu-Ni), nickel-chromium (Ni-Cr) and the like. A substantially central portion A of the metal plate 1 is sealed with a molding resin body 2 as shown in FIGS. 1 and 2 using a molding die (not shown). The mold resin body 2 is, for example, PPS (polyphenylene sulfide) or liquid crystal polymer having good heat dissipation. Further, the legs 5, 5 of the external electrode formed by the molding are bent so as to be substantially along the outer peripheral side faces 3, 3 and the bottom face 4 of the molded resin body 2. (FIGS. 3 and 4) If necessary, the surfaces of the legs 5, 5 extending substantially horizontally may be plated before the legs 5, 5 are bent. Alternatively, as shown in FIG. 5, in order to further increase the heat radiation effect, the substantially central portion which is a part of the metal plate 1 is housed or inserted into the case body 6 having a good heat radiation property, and the heat resistance of silicone resin or the like is used. The inside of the case body 6 may be filled with a filler 7 having good heat dissipation and having electric insulation. Alternatively, after the case body 6 is filled with the filler 7, a lid body (not shown) may be covered. Here, the filler 7 is not limited to the silicone resin, and may be another resin type or a composite material as long as the material has similar characteristics. In this way, the power type surface mount low resistor 8 of the present invention is obtained.

When the power type surface mount low resistor 8 is surface mounted on, for example, the conductive portion 10 of the printed circuit board 9, as shown in FIG. The legs 5 and 5 of the power type surface mount low resistor 8 and the conductive portions 10 and 10 are connected using solder 11 or the like.

With such a configuration, a mechanically strong low resistor can be obtained, heat generation or heat distribution can be made uniform, and the degree of heat dissipation can be improved. About a 30% decrease in temperature.

[0011]

[Effect of the device]

 According to the present invention, since the low resistance body and the external electrode are integrated, mechanical strength and reliability can be improved. Also, because both ends of the resistor / external electrode are sealed with a heat-dissipating mold resin body so as to be led out to the outside, or a filler having heat resistance, heat dissipation, and electrical insulation is filled in the case body. Since it is used, it has good solderability, facilitates automatic surface mounting, and improves mounting density. Moreover, since the manufacturing process can be simplified and automatic mounting can be performed, mass production efficiency can be improved at low cost.

Further, in the case of a low resistance device, a slight increase or decrease in the resistance value also affects the accuracy of the product, but according to the present invention, there is no connecting portion between the low resistance body and the external electrode, so that unnecessary contact is avoided. It is possible to secure a low resistance value without adding parts. In addition, during energization, current concentration or heat concentration does not occur at the connection part, and heat generation or heat dissipation becomes uniform, so that thermal deterioration or characteristic deterioration of the product does not occur. Further, the heat-dissipating and heat-dissipating fillers, which both have electric insulation and are sealed by the molded resin body, are combined with the case body, so that the heat dissipating effect is increased.

[Brief description of drawings]

FIG. 1 is a plan view of a power type surface mount low resistor in a state in which a foot portion led to the outside of a low resistance body / external electrode according to an embodiment of the present invention is substantially horizontal.

FIG. 2 is a vertical sectional view taken along line XX of FIG.

FIG. 3 is a plan perspective view showing a state in which the foot portion of FIG. 2 is bent substantially along a side surface and a part of a bottom surface of the molded resin body.

FIG. 4 is a vertical cross-sectional view taken along line YY of FIG.

FIG. 5: The metal plate is housed or inserted into the case body, and the case body is covered with a heat-resistant and heat-dissipating filler. FIG. 4 is a vertical cross-sectional view showing a state in which a bending process is performed substantially along a side surface and a part of a bottom surface.

FIG. 6 is a partial cross-sectional view showing a state where the printed circuit board is mounted by soldering.

[Explanation of symbols]

 1. Metal plate 2. Molded resin body 3. Side surface 4. Bottom surface 5. Foot 6. Case body 7. Filler 8. Power type surface mount low resistor 9. Printed circuit board 10. Conductive part 11. solder

Claims (1)

[Scope of utility model registration request] 1. At least nickel silver, copper-nickel (Cu-
Ni) or a nickel / chromium (Ni-Cr) low-resistive body and a mold resin body having electrical insulation, or at least nickel silver, copper / nickel (Cu-Ni), nickel One of a low resistance body made of chromium (Ni-Cr), a case body having heat resistance and electric insulation, and a filler having heat resistance and heat dissipation and electric insulation. A power type surface mount low resistor characterized by comprising: