JP2001326442A - Fet mounting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an FET mounting structure, by which a plurality of FETs can be easily and efficiently mounted on a circuit board. SOLUTION: FETs 1 are mounted on a circuit board 3 via a resin plate 2. Truncated cone shaped guide holes 23, 24 are formed in the resin plate to guide lead terminals 12 to mounting positions on the circuit board. Even when there are variations in bending directions and positions of lead terminal end portions 12a, these lead terminal ends 12b can be aligned at constant positions by inserting them into the guide holes. By utilizing the resin plate 2, the work of inserting and fixing the lead terminal ends 12b into the circuit board 3 can be done easily and efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FET mounting structure capable of mounting an FET on a circuit board with good workability.

[0002]

2. Description of the Related Art An FET (electrolytic effect transistor) is widely used as a switching element for switching energization of a coil in a motor driver or the like. This FET generally includes a flat rectangular chip as its main body and three lead terminals extending from the side of the chip. The leading end of the bent lead terminal is inserted into an insertion hole formed on the surface of the circuit board and welded.

[0003]

However, in the conventional FET mounting work, especially when mounting a large number of FETs on a circuit board, the bending angles of the respective lead terminals of the FETs vary, or the bending angles may vary. However, there is a problem that the work of inserting and fixing the lead terminals to the circuit board cannot be easily performed due to the fact that they are not right angles.

[0004] In view of this point, an object of the present invention is to solve the problem of F
An object of the present invention is to propose an FET mounting structure capable of efficiently performing an operation of mounting an ET on a circuit board.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an FET mounting structure for mounting a plurality of FETs on a circuit board, comprising a resin plate mounted on a surface of the circuit board. A guide hole for inserting each of the lead terminals of each FET is formed in the resin plate, and the guide hole is formed so as to be at a fixed angle with respect to the surface of the circuit board, A lead terminal of the FET is inserted into the circuit board through the guide hole.

Here, in order to facilitate the work of inserting the lead terminals, the opening of the guide hole on the lead terminal insertion side is larger than the opening on the front surface side of the circuit board. It is desirable to have such a truncated cone shape.

Generally, since the lead terminals are bent at right angles, the guide holes are vertical guide holes perpendicular to the surface of the circuit board.

In this case, the heat sink may be attached to the FET such that the FET is interposed between the heat sink and the resin plate.

Next, the present invention relates to a method of mounting an FET using the resin plate having the above-mentioned structure, wherein the tip of a lead terminal of the FET is inserted into the guide hole formed in the resin plate, and the The resin plate after the lead terminal is inserted is attached to the surface of the circuit board.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an FET mounting structure according to the present invention will be described below with reference to the drawings.

FIG. 1 is a view for explaining the FET mounting structure of the present embodiment, and FIG. 1A is a schematic view of a resin plate.
(B) is a configuration diagram showing a state where the FET is mounted on a circuit board. Explaining with reference to these drawings, in the FET mounting structure of the present example, many FETs 1 are mounted on the surface of the circuit board 3 via the resin plate 2.

The resin plate 2 has an elongated rectangular parallelepiped shape, a back surface 21 is a circuit board mounting surface, and a plurality of guide holes 23 and 24 are formed on the front surface 22 in two rows. (In FIG. 1A, only one row of guide holes 23 is shown.) Each guide hole 2 in this example
3 and 24 have a truncated cone shape so that the opening on the side of the surface 22 is large, and are perpendicular to the circuit board surface 31.

Each of the FETs 1 has a flat rectangular parallelepiped chip 11 and an end face 3 of the chip 11.
The lead terminals 12 are provided, and each lead terminal 12 is bent at a right angle at a middle position thereof, and a tip portion 12a extends vertically.

Next, a procedure for attaching the FET 1 to the circuit board 3 using the resin plate 2 having the above configuration will be described. First, as shown in FIG. 1A, the lead terminal tip portions 12a of the FETs 1 are inserted into the respective guide holes 23 and 24 of the resin plate 2 from the plate surface 22 side. In this insertion operation, each of the guide holes 23 and 24 has a truncated cone shape, and the opening on the side of the plate surface 22 is large, so that the insertion can be easily performed. In addition, even if the directions of the lead terminal tip portions 12a are not aligned, they are smoothly guided by the inner peripheral surface of the conical guide hole. As a result,
The lead terminal tips 12b protruding downward from the small openings of the guide holes 23 and 24 on the side of the plate back surface 21 are aligned at a predetermined position.

Thereafter, the resin plate 2 on which the FET 1 has been mounted is placed on a predetermined position on the front surface 31 of the circuit board 3, and the fixing screws 4 and the like are mounted on the circuit board front surface 31 from the back side of the board. Secure with fastening hardware.

Here, each lead terminal tip 12b of each FET 1 attached to the resin plate 2 is positioned by the guide holes 23 and 24. Therefore, when the resin plate 2 is mounted on the circuit board surface 31, each lead terminal tip 12b is
In a state in which it exactly faces the corresponding insertion portion. Therefore, if each FET is pushed, each FET1
Of the lead terminal 12b can be inserted into the circuit board 3 and fixed.

Thereafter, the heat radiating plate 5 is attached to the surface of the chip 11 of each FET 1 on the side opposite to the resin plate 2 by a fastener such as a fixing screw 6. Each FET1
Since the chip 11 is mounted on the resin plate surface 22, the mounting height of each FET on the circuit board is uniform by the plate surface 22. Therefore, each F
The degree of adhesion of the ET1 to the heat sink 5 is improved. That is, since the surface of the chip 11 of each FET 1 is aligned,
Each of the FETs 1 is in a state of being in close contact with the plate-shaped heat sink 55. As a result, the heat dissipation of the FET can be improved.

Furthermore, in this example, since each FET 1 is mounted on the circuit board 3 via the resin plate 2, the heat generated by each FET 1 is not directly transmitted to the circuit board 3, so that the heat generated by the FETs causes Adverse effects can be suppressed.

[0019]

As described above, according to the FET mounting structure and the mounting method of the present invention, a resin plate having a guide hole for inserting an FET lead terminal is prepared, and each of the FET plates is inserted through the resin plate. Are inserted into the circuit board.

Therefore, according to the present invention, even if there are variations in the positions of the tips of the lead terminals of the FETs, these variations are corrected by the guide holes in the resin plate. Therefore, the work of attaching the FET to the circuit board can be performed simply and efficiently.

Further, in the present invention, since the guide hole has a truncated conical shape, even if the bending direction and the like of each lead terminal vary, they can be easily inserted into the guide hole and their tips can be set to predetermined positions. Can be guided to the location.

Further, since the resin plate is interposed between each FET and the circuit board, it is possible to suppress or avoid the adverse effect of the heat generated by the FETs on the circuit board.

Further, each FE is formed by a resin plate.
Since the mounting heights of the T with respect to the circuit board can be made uniform, the heat sink can be brought into close contact with these FETs. Therefore, heat generated from the FET can be efficiently released.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams for explaining an FET mounting structure to which the present invention is applied. FIG. 1A is a configuration diagram of a resin plate, and FIG. 1B is a configuration showing an FET mounted on a circuit board. FIG.

[Explanation of symbols]

 Reference Signs List 1 FET 11 Chip 12 Lead terminal 12a Lead terminal tip 12b Lead terminal tip 2 Resin plate 21 Back plate 22 Plate surface 23, 24 Guide hole 3 Circuit board 31 Circuit board surface 4, 6 Fixing screw 5 Heat sink

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E313 AA07 AA11 CE01 CE11 FF08 FF22 5E336 BB01 BC04 BC14 CC03 CC57 DD02 EE12 GG03 5F036 AA01 BA04 BA23 BB01 BC03

Claims (5)

[Claims] An FET mounting structure for mounting a plurality of FETs on a circuit board, comprising: a resin plate mounted on a surface of the circuit board, wherein the resin plate has lead terminals of each FET. A guide hole for insertion is formed, the guide hole is formed so as to be at a fixed angle with respect to the surface of the circuit board, and the lead terminal of the FET is inserted into the circuit board through the guide hole. An FET mounting structure, characterized in that: 2. The FET according to claim 1, wherein the guide hole has a truncated conical shape such that an opening on the lead terminal insertion side is larger than an opening on the front surface side of the circuit board. Mounting structure. 3. The FET mounting structure according to claim 1, wherein the lead terminal is bent at a right angle, and the guide hole is a vertical guide hole perpendicular to a surface of the circuit board. 4. The FET mounting structure according to claim 3, further comprising a heat radiating plate to which the FET is mounted, wherein the FET is sandwiched between the heat radiating plate and the resin plate. 5. The method for mounting an FET using a resin plate according to claim 1, wherein a tip of a lead terminal of the FET is inserted into the guide hole formed in the resin plate, and a lead of each FET is mounted. A method for mounting an FET, comprising mounting the resin plate after the terminal is inserted on a surface of the circuit board.