JPH0576072U - Board ground connection structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a ground connection structure for a substrate, which uses a component instead of a ground screw to reduce the material cost and the assembly cost and can surely drop the ground. In a ground connection structure of a substrate, which has a ground pattern 3 on an insulating layer 4 laminated on a substrate 5, and the ground pattern 3 and the substrate 5 are grounded, a hole 6 of the substrate 5 is provided. A ground connection mechanism for a board, in which the metal pin 1 is fixed to the above and the metal pin 1 and the ground pattern 3 are connected by soldering.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a substrate ground connection structure applicable to, for example, a spindle motor for a floppy disk drive.

[0002]

[Prior Art]

 In a general 5-inch or 3.5-inch floppy disk drive, etc., a ground pattern is provided on the substrate on which a pattern is formed, and a structure is formed in which a ground is provided to other parts. There is. An example of the ground connection structure of such a substrate will be described with reference to the drawings. In FIG. 5, the entire one surface of the iron substrate 15 is covered with the insulating layer 14. A grounding pattern 13 is formed on the insulating layer 14, and a hole portion 16 penetrating the insulating layer 14 and the substrate 15 from the ground pattern 13 is formed. The ground screw 11 is tightened. When the ground screw 11 is tightened, it penetrates through the ground pattern 13, the insulating layer 14 and the substrate 15, and the tip portion projects to the surface of the floppy disk drive main body 17 side opposite to the insulating layer 14.

The ground pattern 13 and the iron substrate 15 are electrically connected via the ground screw 11, and it is possible to ground the ground pattern 13 to the substrate 15 via the ground screw 11.

[0004]

[Problems to be solved by the device]

 In the earth connection structure of the board as described above, the earth screw 11 which is a dedicated component and which is expensive is used, and the earth screw 11 is fixed to the iron board 15 only by tightening. As described above, when the earth screw 11 is tightened and fixed, the earth screw 11 may be insufficiently tightened or the earth screw 11 may be loosened for some reason. In such a case, the ground does not fall normally.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to surely remove the ground while reducing the material cost and the assembly cost by using a part replacing the ground screw. Another object of the present invention is to provide a ground connection structure for a substrate.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a ground connection structure of a base plate, which has an ground pattern on an insulating layer laminated on a substrate, and grounds the ground pattern and the substrate. The metal pin is fixed to the hole of the substrate, and the metal pin and the ground pattern are connected by soldering.

[0007]

[Action]

 The ground can be dropped by forming a hole penetrating the board from the ground pattern on the board, inserting the metal pin, and soldering and joining the ground pattern and the metal pin.

[0008]

【Example】

 Hereinafter, a ground connection structure of a substrate according to the present invention will be described with reference to the drawings. In FIG. 1, an insulating layer 4 is formed on a conductive substrate 5 made of iron or the like, and an earth pattern 3 is formed on the insulating layer 4. On such a substrate 5, a hole portion 6 penetrating from the ground pattern 3 side is formed. The hole 6 has a circular cross-sectional shape, and the diameter thereof is large enough to allow the metal pin 1 to be inserted by press fitting. As shown in FIG. 2, the metal pin 1 has a prismatic shape and a square cross section. The metal pin 1 is made of iron or copper having excellent conductivity and good solderability, or the surface of which is plated with a material having good solderability, and the dimension is longer than the thickness of the substrate 15, and In order to facilitate insertion into the hole 6 as indicated by reference numeral 1a, the corners of the bottom are chamfered as necessary. The chamfered portion 1a may be formed at both ends of the metal pin 1 or may not be formed at all.

Cream solder 2 is applied to the ground pattern 3 of the substrate 5 in advance, the metal pin 1 is attached in the hole 6 by press fitting, and after the press fitting, it is heated in a reflow furnace. When the prismatic metal pin 1 is inserted into the circular hole 6, a gap 7 remains around the metal pin 1 as shown in FIG. 3, but this gap is generated by heating in the reflow furnace. The cream solder 2 flows into the ground pattern 3 from above the ground pattern 3 to fill the gap 7 to enhance the fixing strength and conductivity of the metal pin 1.

As described above, since the metal pin 1 is assembled to the substrate 5 by reflow soldering, the metal pin 1 can be firmly fixed while being electrically connected to the substrate 5. Therefore, the ground can be surely dropped. Further, since the metal pin 1 is soldered, it does not loosen afterwards and has high reliability. Further, since the general prismatic metal pin 1 is used, it is not necessary to use a costly component dedicated to grounding, and the material cost can be reduced as compared with the conventional one.

The earth connection structure using the metal pin 1 is formed on the substrate through the following steps. A circular hole 6 is formed in the substrate composed of the substrate 5, the insulating layer 4 and the earth pattern 3 from the side of the earth pattern 3 by pressing. After the cream solder is printed on the ground pattern 3 on the board, electronic parts such as ICs and resistors are mounted. The metal pin 1 is press-fitted into the substrate and temporarily assembled. Put in a reflow furnace and reflow solder the temporary assembly part of the metal pin 1.

As can be seen from the manufacturing process described above, the metal pin 1 is assembled by a process of placing it in a reflow furnace and soldering it like other components such as IC and resistors, and thus manufacturing the conventional ground connection structure. The assembly process is reduced compared to the process. This also leads to a reduction in assembly costs. In addition, such a manufacturing process is suitable for manufacturing by an automatic machine, and the effect is even greater if it is manufactured by an automatic machine.

If the metal pin 1 is press-fitted into the hole 6 with a large impact, scattering of the applied cream solder 2 and displacement or scattering of mounted electronic parts such as ICs and resistors may occur. Be reminded. In this way, if the impact when the metal pin 1 is press-fitted is anxious, the manufacturing procedure described above is partially changed, and the metal pin 1 is temporarily press-fitted into the hole 6 formed through the ground pattern 3. After assembling, apply cream solder 2 to mount electronic parts. However, the cream solder 2 can be applied only to the flat surface portion, and cannot be applied to the three-dimensional portion where the metal pin 1 projects from the substrate. Therefore, when the metal pin 1 is temporarily assembled by press fitting, the uppermost part of the metal pin 1 is aligned with the ground pattern 3. By doing this, the protrusion by the metal pin 1 on the ground pattern 3 side of the base plate 5 is eliminated and the surface becomes flat, so that the cream solder 2 is applied to the portion of the ground pattern 3 where the metal pin 1 is temporarily assembled. You will be able to. After that, electronic parts such as ICs and resistors are mounted, placed in a reflow furnace, and the electronic parts and the metal pins 1 are soldered and connected to the substrate 5. Through the procedure described above, the ground connection structure for the substrate as shown in FIG. 4 is formed.

In the present invention, the case where the hole 6 is a round hole, and the shape of the metal pin 1 is a prism and the cross-sectional shape is square has been described as an example, but the present invention is not limited to this. The shape is not particularly limited as long as a gap is created in the hole of the substrate when the metal pin is press-fitted. Therefore, contrary to the above-mentioned embodiment of the present invention, the cross-sectional shape of the metal pin may be round so that the hole has a square shape. The cross-sectional shape of the pin may be a square or more equilateral polygon (hexagon, octagon, dodecagon). Alternatively, a hoop-shaped wire may be pressed into the hole of the substrate and cut to form a metal pin. The same effect as that of the above-described embodiment can be expected.

In the embodiment, the board is made of a conductive material such as an iron plate, but the material is not limited to this, and an insulating material such as phenol may be used. In this case, the metal pin is crimped to another conductive earth member to make it conductive. It is possible to drop the ground from the ground pattern to another conductive ground member via the metal pin.

[0016]

[Effect of the device]

 According to the present invention, since the ground connection structure of the board is formed by forming the holes in the board and connecting the metal pins by soldering, the reliability such as the strength of the ground is improved and the material cost is reduced. Can be reduced. In addition, it is possible to reduce the assembly process and the assembly cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a substrate ground connection structure according to the present invention.

FIG. 2 is a perspective view showing an example of a metal pin used for the ground connection structure of the same substrate.

FIG. 3 is an enlarged view of essential parts showing an example immediately after press-fitting of metal pins on the same substrate.

FIG. 4 is a sectional view showing another embodiment of the same substrate.

FIG. 5 is a cross-sectional view showing an example of a conventional board grounding structure.

[Explanation of symbols]

 1 Metal Pin 2 Solder 3 Ground Pattern 4 Insulating Layer 5 Board 6 Hole

Claims (1)

[Scope of utility model registration request] 1. A ground connection structure for a board, comprising a ground pattern on an insulating layer laminated on the board, wherein the ground pattern and the board are grounded, and a metal pin is fixed to a hole of the board. In addition, the ground connection structure of the substrate is formed by soldering the metal pin and the ground pattern.