JPH10229001A - Surface-mounted type fixed resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-mounted type fixed resistor which has a simple structure, a small size, and a good heat radiating property, and can be manufac tured easily. SOLUTION: A surface-mounted type fixed resistor is provided with a rectangular thin plate-like heat radiator 12, made of an insulating material composed of a ceramic, etc., a resistor 14 composed of a metallic sheet, which is laminated upon the heat radiator 12 and both end sections of which are bent in U-shapes as engaging sections along both end sections of the heat radiator 12, and an engaging section 16 which is integrally formed with the side faces of the resistor 14 and bent along the other both end sections of the heat radiator 12. The surface of the resistor 14 is coated with a heat-resistant epoxy resin, etc., and the heat-resistant resin film is exposed to the outside space.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-mounted fixed resistor having a predetermined resistance value, which is mounted on a circuit board of an electronic device.

[0002]

2. Description of the Related Art Conventionally, a resistor mounted on a circuit board is:
As disclosed in Japanese Utility Model Laid-Open No. 5-82002,
In some cases, a metal resistor was buried in a mold resin body having electrical insulation with both ends protruding. Also, instead of molding resin, the central part of the resistor is housed in a case, and this case is filled with a heat-resistant, heat-dissipating, and electrically insulating filler, and both ends of the resistor are molded resin or case. Some of them were bent downward in a U-shape along the lines to form electrode portions that were soldered to the surface of the circuit board.

Further, as disclosed in Japanese Patent Application Laid-Open No. 6-267707, there has been proposed a metal resistor in which both side surfaces are sandwiched between insulating members with both ends protruding. ing. In this resistor, both ends of the resistor are bent so as to enclose the ends of one of the insulating members, and serve as electrode portions that are soldered to the surface of the circuit board.

[0004]

In the former case of the above-mentioned prior art, it is necessary to perform an operation of integrally molding a resistor with a mold resin body or to fill a case with a filler, which complicates the manufacturing process. there were.

In the latter case of the prior art, the cost is high because the resistor is sandwiched between insulating members, and the work of bonding the resistor to the resistor in a sandwich manner is complicated and poor in workability.

The present invention has been made in view of the above-mentioned problems of the conventional technology, and has a simple structure and is easy to manufacture.
It is an object of the present invention to provide a small surface mount fixed resistor having good heat dissipation.

[0007]

According to the present invention, there is provided a thin plate-shaped radiator which is an insulator such as a rectangular ceramic, and both ends of which are laminated on the radiator and whose both ends are formed in a U-shape along both ends of the radiator. A resistor made of a metal plate that is bent into a mold to form an engaging portion, and an engaging portion that is integrally formed on the side surface of the resistor and that is bent along the other end of the heat radiator are integrally formed. Surface mounted fixed resistor. Further, the surface of the resistor is coated with a resin such as a heat-resistant epoxy resin, and the coating of the heat-resistant resin is exposed to an external space.

In the surface mount type fixed resistor according to the present invention, one side of the resistor is open to the air, and the other side is provided with a heat radiator made of ceramics having relatively excellent heat conduction. The heat generated in is efficiently dissipated, and the temperature of the resistor does not become high.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show a surface-mounted fixed resistor 10 according to a first embodiment of the present invention. The fixed resistor 10 has a rectangular plate-shaped radiator 12, and the radiator 12 is made of ceramics such as alumina porcelain. is made of. Heat radiator 1
2, a plate-shaped resistor 14 made of a copper-nickel alloy or the like is provided on one side surface. As shown in FIG. 3, the resistor 14 is formed to have substantially the same width as the radiator 12, and both ends thereof are engagement portions formed to be longer than the radiator 12 so as to wrap both ends of the radiator 12. The engaging portion forms an electrode 18 described later.

On both side edges near the center of the resistor 14, projecting portions 16 are formed, each serving as an engaging portion projecting sideways.
The radiator 12 is held so as to be wrapped in a U-shape. Solder plating 19 is applied to the front and back surfaces of the engaging portion of the resistor 14 and both ends forming the electrode 18, and the heat resistant epoxy coating 17 is applied to the front and back surfaces of the other portions of the resistor 14.

The heat radiator 12 and the resistor 14 are integrated by caulking or an adhesive, and both ends of the resistor 14 extending laterally from the heat radiator 12 are aligned along the side edge of the heat radiator 12. The electrode 18 is bent in the shape of a triangle, holds the heat dissipator 12, and is soldered to the surface of a circuit board (not shown). The protruding portion 16 is also bent in a U-shape along side edges of the heat radiator 12 that are substantially perpendicular to both ends covered with the resistor 14, and holds the heat radiator 12.

The surface mount type fixed resistor 10 of this embodiment
Is used in such a manner that a pair of electrodes 18 are respectively brought into contact with the surface of a land formed on a circuit board (not shown), and are surface-mounted by soldering.

The surface mount type fixed resistor 10 of this embodiment
According to this, a part of the heat generated in the resistor 14 during use is transmitted to the radiator 12 and is efficiently radiated, and the surface of the resistor 14 is also efficiently radiated into the air. For this reason,
The operating temperature does not increase and the size can be reduced. Further, the surface-mount type fixed resistor 10 has a simple shape and a simple structure, so that the assembling work is easy and the cost is low. Since the electrodes 18 are previously plated with solder, soldering to the circuit board is easy and workability is good.

Next, another embodiment of the surface mount type fixed resistor according to the present invention will be described with reference to FIGS. Here, the same members as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. First, the surface mount type fixed resistor 20 shown in FIGS. 5 to 8 has a small protrusion 26 which is an engagement portion of the resistor 24 and is formed to have a protrusion amount enough to hold the side surface of the heat radiator 12. It is. According to the surface-mounted fixed resistor 20 of this embodiment, only the electrode portion 28 is located on the bottom surface side, so that a short circuit with other wiring on the circuit board can be prevented.

Further, in still another surface mount type fixed resistor 30 shown in FIGS. 9 to 12, a projecting portion 36 which is an engagement portion of a resistor 34 holding the heat radiator 12 is formed by forming both side edges of an electrode portion 38. It is formed in each part. As a result, only the electrode portion 38 is located on the bottom surface side, and it is possible to prevent a short circuit with other wiring on the circuit board, and to hold the radiator 12 by the four projecting portions 36, so that the radiator 12 can also have high holding strength.

The surface mount type fixed resistor according to the present invention is not limited to the above embodiment. For example, the resistor may be a copper-nickel alloy, a nickel-chromium alloy, nickel silver or other desired resistance. Any metal can be used as long as it can be obtained, and the material and the like of the heat radiator can be appropriately changed.

[0017]

The surface mount type fixed resistor according to the present invention has a simple structure, is easy to manufacture, and has a low cost, with the radiator held by the resistor. Furthermore, it is small and excellent in heat dissipation.

[Brief description of the drawings]

FIG. 1 is a front view of a surface-mounted fixed resistor according to an embodiment of the present invention.

FIG. 2 is a plan view (A) and a right side view (B) of the surface-mounted fixed resistor of this embodiment.

FIG. 3 is a plan view showing an unfolded state before the resistor of this embodiment is attached to a heat radiator.

FIG. 4 is a front view showing an unfolded state before the resistor according to the embodiment is attached to a radiator.

FIG. 5 is a plan view illustrating a developed state of a resistor according to another embodiment of the present invention before being attached to a heat radiator.

FIG. 6 is a front view showing an unfolded state of the resistor of this embodiment before being attached to a heat radiator.

FIG. 7 is a plan view (A) and a right side view (B) of the surface-mounted fixed resistor according to the present embodiment.

FIG. 8 is a front view of the surface mount fixed resistor according to the embodiment.

FIG. 9 is a plan view showing a developed state of a resistor according to yet another embodiment of the present invention before being attached to a heat radiator.

FIG. 10 is a front view showing a developed state of the resistor according to the embodiment before being attached to a heat radiator.

FIG. 11 is a plan view (A) and a right side view (B) of the surface-mounted fixed resistor of this embodiment.

FIG. 12 is a front view of the surface-mounted fixed resistor according to the embodiment.

[Explanation of symbols]

 10, 20, 30 Surface mount type fixed resistor 12 Heat radiator 14, 24, 34 Resistor 16, 26, 36 Projection 18, 28, 38 Electrode

Claims (2)

[Claims] 1. A radiator made of a thin plate-like insulator, a resistor made of a metal plate laminated on the radiator and having both ends bent in a U-shape along the end of the radiator, An engaging portion formed on the side surface of the resistor and bent along the other end of the heat radiator is provided, and the surface of the resistor is in contact with an external space via a predetermined coating. Surface mount type fixed resistor. 2. The heat dissipator is made of ceramic, four sides of the heat dissipator are held by engagement portions of the resistor, and the surface of the resistor is coated with a heat-resistant resin. 2. The surface-mounted fixed resistor according to claim 1, wherein the fixed resistor is exposed to an external space.