JPH0639496Y2 - Fixing structure of FPC to insulating case - Google Patents

Description

[Detailed Description of the Invention] Industrial field of application The present invention relates to an improvement of a fixing structure between an FPC and an insulating case in an electric junction box having an FPC (flexible printed board) as a circuit component.

2. Description of the Related Art Conventionally, as a fixing structure of this type, as shown in FIGS.
There is a type in which a plurality of circular holes 2 are provided in a PC 1 and a boss 4 having a truncated conical portion 4a at a tip portion protruding from an insulating case 3 is press-fitted. The hole diameter a and the boss outer diameter b have a relationship of a <b.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional press-fitting and fixing structure, stress is applied to the edge of the circular hole 2 to cause tearing, and as shown in FIG. Since it is necessary to absorb the tolerance by making it larger than the distance l'between the bosses 4 and 4,
There was a risk that the FPC1 could not be fixed loosely and tidily, and could swing and short-circuit with other electronic components when the vehicle was running.

An object of the present invention is to provide a fixing structure that does not cause such a problem.

Means for Solving the Problems As shown in FIGS. 1 to 3, an FPC fixing structure of an FPC of the present invention includes a boss 4 having a frustoconical portion 4a at its tip as shown in FIGS. In the fixing structure in which the boss 4 is projected and the boss 4 is press-fitted into the circular hole 2 provided in the FPC 1, the inner diameter c of the circular hole 2 is formed smaller than the end diameter e of the truncated conical portion 4a, and the circular shape A chrysanthemum-shaped notch 2a is provided at the hole edge of the hole 2, and a diameter d of an outer circumference circle 2b of the notch S is formed to be larger than an outer diameter f of the boss 4, and a mating case 5 facing the insulating case 3 is formed. Is provided with a receiving cylinder 6 for the boss 4, and the boss 4 is inserted into the receiving cylinder 6 while the cutting piece S of the circular hole 2 is pushed open by the boss 4 to receive the cutting piece S. It is characterized by being sandwiched between 6 and the boss 4.

In FIG. 1, the insulating case 3 is formed as an under case of the electric junction box A, and is paired with the opposing upper case 5 which is an opposite case, and the FPC 1 is housed and fixed in both cases. In this embodiment, four bosses 4 are provided on the under case 3 and four receiving cylinders 6 corresponding to the inner wall of the upper case 5 are provided on the under case 3. The inner diameter g of the receiving cylinder 6 is larger than the outer diameter f of the boss 4. Further, a frame-shaped connector insertion portion 7 is formed in the upper case 5, and the group of terminals 8 press-fitted and fixed in the hole 7a at the bottom of the insertion portion 7 is soldered to the land 9a of the circuit conductor 9 of the FPC 1. Connected.

Action As shown in Figs. 4 and 5, when the tip of the boss 4 (the truncated conical portion 4a) is lightly pressed against the circular hole 2 of the FPC 1, the hole diameter is expanded by the notch 2a, and the notch S is opened to make the truncated head. Conical part 4a
It will be in a state of getting on the side of. Therefore, when the upper case 5 is covered, the boss 4 is expanded while the notch piece S is further expanded.
Enters the receiving cylinder 6, and the FPC 1 is sandwiched and fixed between the insulating case 3 and the receiving cylinder 6.

In this way, by providing the cut 2a in the circular hole 2,
FPC1 can be fixed without applying stress,
The dimensional tolerance can be absorbed naturally, and the cut piece S is a boss 4.
Since it closely contacts the outer peripheral surface of FPC1, there is no displacement of FPC1.

EFFECT OF THE INVENTION The present invention is a FPC in which an insulating case is provided with a protruding boss having a truncated cone shape, and the boss is press-fitted into a circular hole provided in the FPC.
In the fixing structure to the insulating case, the inner diameter of the circular hole is formed to be smaller than the end diameter of the frusto-conical portion, and a chrysanthemum-shaped notch is provided at the hole edge of the circular hole. Form the diameter of the outer circle larger than the outer diameter of the boss,
The receiving case for the boss is provided on the mating case opposite to the insulating case, and the boss is inserted into the receiving tube with the cut piece of the circular hole being pushed open by the boss to receive the cut piece. Since it has a structure sandwiched between the cylinder and the boss, it can be clamped and fixed easily and securely without applying stress to the FPC and without worrying about dimensional tolerances, eliminating the conventional press-fitting process and tearing the FPC by press-fitting. Can be eliminated.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an electric junction box using the fixing structure of the present invention, FIGS. 2a and 2b are perspective views (a) and plan views (b) of a circular hole portion of an FPC, and FIG. 3 is a book. FIG. 4 is a sectional view of the fixing structure of the invention in a separated state, FIG. 4 is a sectional view of the same semi-fixed state, FIG. 5 is a perspective view of the same fixing state, and FIGS. It is a figure. 1 ... FPC, 2 ... circular hole, 2a ... notch, 2b ... outer circle, 3 ... insulating case (undercase), 4 ... boss,
4a: truncated cone, S: notch

Claims (1)

[Scope of utility model registration request] 1. A boss having a frustoconical end portion protruding from an insulating case, and the boss being press-fitted into a circular hole provided in an FPC.
In the fixing structure of the PC to the insulating case, the inner diameter of the circular hole is formed smaller than the end diameter of the frustoconical portion, and a chrysanthemum-shaped notch is provided at the hole edge of the circular hole, and the notch The outer diameter of the outer diameter of the boss is formed larger than the outer diameter of the boss, the receiving case for the boss is provided in the mating case facing the insulating case, and the notched piece of the circular hole is pushed open by the boss, A fixing structure characterized in that the boss is inserted into the receiving cylinder, and the cut piece is sandwiched between the receiving cylinder and the boss.