JPH0214127Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a grounding connection structure for connecting a heat radiator attached to an electrical component to a wiring board and grounding it.

(Prior art) As a control device that controls an AC motor, for example, the circuit of a control semiconductor element is connected to a printed board (wiring board), and power components such as power transistors that require separate heat radiation are connected to a heat radiator. The assembly is carried out by attaching and fixing both to both sides of the framework.

When using a non-conductive plastic frame for the above framework, use a grounding cable or connecting fittings to connect the printed circuit board's grounding line to the heatsink in order to prevent the negative effects of high-frequency noise induced from the power transistor. It is necessary to connect and ground the heatsink itself.

It is difficult to use a grounding cable in an automatic assembly process because it requires special equipment design, and a connection fitting made of sheet metal is used for grounding the radiator.

FIG. 3 is an explanatory diagram showing an example of this type of connection fitting. The upper part of the heatsink is screwed to contact the ground pattern surface of the printed circuit board, thereby grounding the heatsink itself.

(Problem to be solved by the invention) When using the above-mentioned connecting fittings, it is possible to ground the radiator because the fittings are made from sheet metal, but it is difficult to connect the connecting fittings on the radiator during the assembly process. At the same time, problems have arisen that require an increase in mounting space and restrictions on the wiring pattern on the bottom surface of the printed circuit board.

The present invention was developed in view of these problems, and its purpose is to fix the heat sink attached to the power components on one side of the plastic frame, and hold the electrical circuit wiring board on the other side. The radiator is for grounding the radiator held a predetermined distance away, and the radiator can be connected to the ground line of the wiring board, and the overall assembly process can be increased. An object of the present invention is to provide a grounding connection structure which reduces restrictions on the wiring pattern of a printed board.

(Means for Solving the Problems) According to the present invention, a radiator is fixed to one side of a plastic frame, and a wiring board for an electric circuit is fixed to the other side at a predetermined distance from the radiator. In the structure in which the heat sink is connected to the ground pattern of the wiring board, a connecting tool made of a good electrical conductor is provided on the wiring board side of the plastic frame, and the heat sink is fixed to one end surface of the connecting tool. A mounting hole through which a screw can be inserted is formed, and a claw part is formed on the other end surface to come into contact with the side surface of the holding part of the plastic frame that holds the wiring board, and this connector is inserted into the mounting hole. The wiring board is electrically connected to the radiator by the screws, and when the wiring board is fixed, the end surface on which the claw portion is formed comes into contact with the ground pattern of the wiring board. A grounding connection structure is provided.

(Function) In this invention, one end of the connector is fixed to the plastic frame together with the radiator using the fixing screw of the radiator, and the other end is clamped to the plastic frame while being sandwiched between the printed board and the holding part. The connector is electrically connected to the ground pattern of the printed circuit board, and the other end of this connector has a claw that comes into contact with the side surface of the holding part, so the heatsink can be connected via this connector. In addition to being securely grounded, there is no possibility that the connecting tool will move relative to the holding part during the screw-fastening process during assembly and that their relative positions will not shift.

(Example) Next, an example of the present invention will be described in detail using the drawings.

FIG. 1 is an explanatory view showing one embodiment of the grounding connection structure of the present invention, and FIG. 2 is a perspective view of the connection tool.

In Figure 1, reference numeral 1 is a printed board (wiring board), which is provided with wiring patterns for control semiconductor circuits and power circuits, various electrical components are attached to the top surface, and the bottom surface is is provided with copper foil parts for power circuits and grounding patterns.

Numeral 11 is a screw hole through which a mounting screw 12 is inserted when fixing the printed board 1 to the plastic frame 2, and a copper foil in the pattern of the ground line of the printed board 1 is exposed on the lower surface of the screw hole 11. There is.

The broken line portion of the illustrated printed circuit board 1 shows an example of the copper foil of the ground line on the lower surface.

The plastic frame 2 is made of a molded synthetic resin material, holds the printed board 1 on its upper part, and fixes the heat radiator 3 on its lower part. It is intended as a control unit.

The plastic frame 2 has a holding post 22 inside the upper frame 21, and the upper surface of the holding post 22 and the upper surface of the beam 23 are portions on which the printed board 1 is placed. Further, reference numeral 24 designates mounting holes for the heat radiator 3, and a plurality of holes are bored in the inner frame 25 of the plastic frame 2 in correspondence with the positions of the screw holes 31 of the heat radiator 3.

Reference numeral 4 denotes a connector, which is a part formed by sheet metal processing of a good electrical conductor, such as a copper plate or a brass plate, and its side surface is Z-shaped as shown in FIG. A screw 34 for fixing the heat radiator 3 is tightened to the lower surface of the connector 4, and the heat radiator 3 is tightened to the bottom surface of the connector 4.
A mounting hole 42 is formed to be electrically connected to the mounting hole 42, and the upper surface portion of the other end is in contact with the ground line pattern of the printed board 1, and the mounting screw 12 is inserted therein.
A mounting hole 41 is formed through which the mounting hole 41 can be inserted.

Further, the connecting tool 4 has a claw portion 43 on the lower side of its upper surface portion, which comes into contact with the side surface of the holding column 22 of the printed board 1. This can be done, for example, by the holding column 22.
If it has a square prism shape, the claw part 4
3, and when the connecting tool 4 is placed over the upper part of the holding column 22, it is configured so that the positions of the two do not shift during screw-fastening work.

Also, the height dimension of the connector 4 is the holding column 22.
The mounting hole 41 corresponds to the height of the holding column 22.
The mounting hole 42 is configured to match the mounting hole 24 of the middle frame 25 in the upper screw hole.

The heat radiator 3 radiates heat generated during operation of the power transistor 32 into the air, and is made of aluminum alloy or the like in a shape having a large number of heat radiating fins 33.
It is fixed to the plastic frame 2 with mounting bolts 34 through mounting holes 24 in the middle frame 25.

Next, the assembly of the printed board 1, plastic frame 2, radiator 3, connector 4, etc. in this embodiment will be explained.

First, the connecting tool 4 is placed on the holding column 22 of the plastic frame 2 at a predetermined position, and the radiator 3 is screwed with the mounting bolt 34 through the lower mounting hole 42 of the connecting tool 4 and the mounting hole 24 of the middle frame 25. Tighten the hole 31 to fix the heat sink 3 to the plastic frame 2.

Next, the printed board 1 is placed on the holding column 22 or beam 23 covered with the connecting tool 4, and the mounting screw 12 is
The printed board 1 is held in the plastic frame 1 by being tightened to the holding column 22 through the screw hole 11 of the printed board 1.

Through the above assembly process, the potential of the radiator 3 becomes the same potential as the ground line on the lower surface of the printed board 1 via the bolt 34 and the connector 4, that is, the radiator 3 is grounded.

Although the present invention has been described above with reference to the above embodiment, various modifications can be made within the scope of the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the invention) According to the invention, one side of the connecting device made of a good electrical conductor is screwed to the radiator, and the other side is sandwiched between the plastic frame and the printed board, and the grounding pattern of the printed board is Since it is in contact with the radiator, it is possible to easily ground the heatsink without increasing the work process for grounding.Furthermore, it has the effect of not increasing the mounting space or affecting the pattern on the bottom surface of the printed circuit board. is obtained.

According to the present invention, sufficient grounding can be obtained by placing the connecting tool on the holding column from above and tightening the heat sink or printed board, so that automatic assembly by a robot or the like can be easily performed.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing one embodiment of the grounding connection structure of the present invention, Fig. 2 is a perspective view of the connecting device, and Fig. 3
The figure is an explanatory diagram showing an example of a conventional connecting fitting. 1...Printed board (wiring board), 2...Plastic frame, 3...Radiator, 4...Connecting tool, 2
2...Holding pillar.

Claims (1)

[Scope of utility model registration request] A structure in which a radiator is fixed to one side of a plastic frame, and a wiring board for an electric circuit is fixed to the other side at a predetermined distance from the radiator, and the radiator is connected to a ground pattern of the wiring board, A connecting tool made of a good electrical conductor is provided on the wiring board side of the plastic frame, and one end surface of this connecting tool has a mounting hole through which a screw for fixing the heat sink can be inserted, and the other end surface has a mounting hole through which a screw for fixing the heat sink can be inserted. is formed with a claw part that comes into contact with the side surface of the holding part of the plastic frame that holds the wiring board, and this connecting tool is electrically connected to the heat sink by a screw inserted into the mounting hole. . A grounding connection structure, characterized in that when the wiring board is fixed, the end face on which the claw portion is formed comes into contact with a grounding pattern of the wiring board.