JPH0677674A - Joint structure of electrical junction box and electronic circuit unit - Google Patents

Abstract

PURPOSE:To prevent looseness of a bus-bar wiring board inside an electrical junction box and then a failure caused by it by bringing the surface at the connection side of the electronic circuit unit into press contact with the outer surface of a main cover. CONSTITUTION:The title structure is a joint one between an electrical junction box 1' housing a bus-bar wiring board 5 between a main cover 3 and an under cover 4 and an electronic circuit unit 2 incorporating a functional circuit. Then, a boss 20 for clamping is provided in one piece on the inner surface (upper surface) of the under cover 4 instead of providing the boss for clamping at the main cover 3. Further, the boss 20 for clamping is allowed to protrude from the upper surface of the main cover 3 via through holes 21 and 22 which are formed on the bus-bar wiring board 5 and the main cover 3, respectively. With this kind of structure, the looseness of the bus-bar wiring board 5 inside the electrical junction box 1' is eliminated and wear due to sliding for the connection part of connectors can be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure of an electric connection box having a busbar wiring board accommodated between a main cover and an undercover, and an electronic circuit unit containing a functional circuit.

[0002]

2. Description of the Related Art An electronic wiring unit having a built-in functional circuit and an electric connection box having a busbar circuit mainly having a branching function are combined to form one automobile wiring device. It is publicly known, for example, in Japanese Patent Laid-Open No. 64-16117.

In connecting the electric connection box and the electronic circuit unit, the circuits are electrically connected by a connector, but mechanically, the two are connected by using a tapping screw, for example.

An example thereof is shown in FIGS. 4 and 5
6 is an exploded view of the connection structure of the electric junction box 1 and the electronic circuit unit 2, and FIG. 6 shows a state in which both are connected.

The electric junction box 1 includes a bus bar 5a and an insulating plate 5b (see FIG. 5) between the main cover 3 and the under cover 4.
(See the above) and a plurality of bus bar wiring boards 5 are stacked and accommodated. As shown in FIG. 5, the main cover 3 and the under cover 4 are engaged with each other at an engaging portion 6 to be integrated.

In this case, in consideration of the stacking error (dimensional variation) of the bus bar wiring board 5, the dimension a from the engaging portion 6 to the upper end of the bus bar wiring board 5 and the inner surface of the main cover 3 from the engaging portion 6 are considered. The relationship with the dimension b up to is set to a ≦ b.

A cylindrical connector housing 7 is provided on the outer surface of the main cover 3 so that the end portion of the bus bar 5a projects as a male terminal 8 into the connector housing 7, whereby one connector 9 is formed. It is configured.

A plurality of screw tightening bosses 10 are provided on the outer surface of the main cover 3 so as to be coupled to the electronic circuit unit 2. This screw tightening boss 10
On the end face of the, prepared hole 1 for screwing the tapping screw 11
0a is open.

On the other hand, the electronic circuit unit 2 has a structure in which a printed wiring board 14 on which functional elements are mounted is sandwiched between a unit lower case 12 and a unit upper case 13.
When the tapping screw 11 is tightened to the electric junction box 1 side,
The case 12 and the printed wiring board 14 are fastened together by the tapping screw 11.
At this time, the end of the printed wiring board 14 is also sandwiched between the edges of the unit lower case 12 and the unit upper case 13.

On the printed wiring board 13, a mating connector terminal 15 is fixed downward, and when the electronic circuit unit 2 and the electric junction box 1 are mechanically coupled, both connectors 9, 15 are connected to each other. The lower case 13 and the lower case 13 are fitted to each other through the opening 16.

Unit lower case 1 of electronic circuit unit 2
A concave portion 17 for accommodating the screw tightening boss 10 is formed on the lower surface of 3. Also, the unit upper case 1
A recess 18 for accommodating the head of the tapping screw 11 is formed on the upper surface of 2.

The height of the screw tightening boss 10,
In other words, from the outer surface of the main cover 3, the screw tightening boss 1
The relation between the dimension c to the apex of 0 and the height of the recess 17 for accommodating the screw tightening boss 10, that is, the dimension d from the lower surface of the unit lower case 12 to the top wall 19 of the recess 17 is c ≦ d. Is set to.

The electric junction box 1 and the electronic circuit unit 2 thus formed are connected as shown in FIG.
That is, the screw tightening boss 10 on the electric junction box 1 side is inserted into the recess 17 on the electronic circuit unit 2 side, and the tapping screw inserted into the recess 17 from above through the top wall 19 of the recess 17. The tip of 11 is screwed into the prepared hole 10a of the screw tightening boss 10 inserted in the recess 17, whereby the electronic circuit unit 2 is strongly fastened to the main cover 3 of the electrical junction box 1 and integrated. Various wiring devices are assembled.

[0014]

By the way, in this way, the electric connection box 1 and the electronic circuit unit 2 are connected to each other by the tapping screw 11.
When connected with, the bus bar wiring board 5
A gap H1 is formed between the upper end of the main cover 3 and the inner surface of the main cover 3, and a gap H2 is formed between the upper end of the screw tightening boss 10 and the top wall 19 of the recess 17 on the electronic circuit unit 2 side. . As a result, the bus bar wiring board 5 rattles due to the vibration of the automobile, etc., and wear is caused between the terminals of the connectors 9 and 15 due to the vibration. There was a problem that corrosion occurs in the.

The rattling of the bus bar wiring board can be prevented by a method such as heat welding as described in, for example, Japanese Utility Model Laid-Open No. 62-62478, but the work is troublesome. It was unsuitable to apply to the connecting structure of the electric connection box and the electronic circuit unit which are separate parts.

In consideration of the above circumstances, the present invention is a combination of an electric connection box and an electronic circuit unit capable of preventing rattling of a bus bar wiring board in the electric connection box and preventing occurrence of a failure due to the rattling. It is intended to provide a structure.

[0017]

According to the present invention, there is provided a combination structure of an electric connection box having a busbar wiring board accommodated between a main cover and an undercover and an electronic circuit unit having a functional circuit incorporated therein. A boss for screw tightening is provided on the inner surface of the screw boss, and the boss for screw tightening is penetrated through each through hole formed in the bus bar wiring board and the main cover to project from the outer surface of the main cover. The end surface is characterized in that the surface of the electronic circuit unit on the coupling side is brought into pressure contact with the outer surface of the main cover by tightening a screw inserted through the unit upper case from the side opposite to the coupling side. There is.

[0018]

According to the above-described coupling structure, the surface of the electronic circuit unit on the coupling side is pressed against the main cover by fastening the tapping screw, so that the main cover is pushed and the distance between the main cover and the under cover is narrowed. . Therefore, the bus bar wiring board housed during this period is sandwiched between the main cover and the under cover, and rattling does not occur.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In addition, in these figures, FIGS.
The same components as those of the electric junction box and the electronic circuit unit shown in FIG.

In the coupling structure of this embodiment, the screw fastening boss 20 is not provided on the main cover 3, but the screw fastening boss 20 is provided on the inner surface (upper surface) of the under cover 4.
Are projected integrally. The screw tightening boss 20 penetrates through the through holes 21 and 22 formed in the bus bar wiring board 5 and the main cover 3, respectively, and projects from the upper surface of the main cover 3.

The other structure is the same as that of the conventional example shown in FIGS. However, here, the relationship of the respective dimensions of a, b, c, and d is set so that (ba) = (dc) (see FIG. 2).

The electrical connection box 1'and the electronic circuit unit 2 formed in this way are connected to each other as shown in FIG.
The boss side 20 for tightening the screw is the electronic circuit unit 2
Of the tapping screw 11 that is inserted into the concave portion 17 on the side and that is inserted into the concave portion 17 from above through the top wall 19 of the concave portion 17 of the screw tightening boss 20 that is inserted into the concave portion 17. It is screwed into the prepared hole 10a. As a result, the lower surface of the electronic circuit unit 2 is pressed against the upper surface of the main cover 3, and the integrated wiring device is assembled.

According to this structure, the main cover 3 of the electric junction box 1'is pushed downward by the lower surface of the electronic circuit unit 2, so that the inner surface of the main cover 3 contacts the upper end of the bus bar wiring board 5. Therefore, the gap between the upper end of the bus bar wiring board 5 and the inner surface of the main cover 3 is eliminated by the screw fastening. At the same time, the gap between the upper end of the screw tightening boss 20 and the top wall 19 of the recess 17 on the electronic circuit unit 2 side also disappears. Therefore, the bus bar wiring board 5 is prevented from rattling and the tapping screw 11 is prevented from being loosened.

[0024]

As described above, according to the coupling structure of the present invention, the bus bar wiring board in the electrical junction box is free from rattling and wear due to sliding on the connector coupling portion is avoided.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an electric connection box and an electronic circuit unit according to an embodiment of the present invention.

FIG. 2 is an exploded side sectional view of an embodiment of the present invention.

FIG. 3 is an assembled side sectional view of an embodiment of the present invention.

FIG. 4 is an exploded perspective view showing a conventional electrical junction box and electronic circuit unit.

FIG. 5 is an exploded side sectional view of a conventional example.

FIG. 6 is an assembled side sectional view of a conventional example.

[Explanation of symbols]

 1'Electric junction box 2 Electronic circuit unit 3 Main cover 4 Under cover 5 Bus bar wiring board 11 Tapping screw 12 Unit upper case 17 Recessed portion 19 Top wall 20 Screw tightening bosses 21, 22 Through holes

Claims (1)

[Claims] 1. A connection structure of an electric connection box containing a bus bar wiring board between a main cover and an under cover and an electronic circuit unit having a functional circuit built therein, wherein a screw tightening boss is provided on an inner surface of the under cover. The screw tightening boss protrudes from the outer surface of the main cover by penetrating the through holes formed in the busbar wiring board and the main cover, and the end surface of the screw tightening boss is opposite to the coupling side. From the electrical connection box and the electronic circuit unit, the surface of the coupling side of the electronic circuit unit is brought into pressure contact with the outer surface of the main cover by tightening the screw inserted through the unit upper case. Bond structure.