JPH06857Y2 - Chassis base structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a chassis base structure, and more particularly to a structure for assembling a printed circuit board on a frame-shaped frame base used in an electronic tuner or the like.

2. Description of the Related Art As shown in FIGS. 4 and 5, a chassis base structure used in an electronic tuner or the like has a metal-made substantially rectangular frame-shaped chassis base (1) and a plurality of electronic components (2). ) (2) ...
And a printed circuit board (3) on which is mounted, and the printed circuit board (3) is positioned and housed in the chassis base (1). The printed circuit board (3) is positioned by inserting the printed circuit board (3) from one open end of the chassis base (1) and providing protrusions (4) on the inner wall surface of the chassis base (1). This is performed by locking the outer peripheral portion of the printed circuit board (3) to (4) .... As shown in FIGS. 6 and 7, an earth land (5) is electrically conductive to the outer peripheral edge of one surface (lower surface in the drawing) of the printed circuit board (3) positioned in the chassis base (1). It is formed as a part of the pattern (6), and the earth land (5) and the chassis base (1) are electrically and mechanically connected by a solder (7) to ground the conductive pattern (6), and The printed circuit board (3) is fixed to the chassis base (1).

In the chassis base structure, the printed circuit board (3) is fixed to the chassis base (1), and the conductive pattern (6) of the printed circuit board (3) is supplied to the ground land (5) for grounding. In addition, the amount of solder (7) was not uniform, and some variation was likely to occur.
If the amount of the solder (7) varies as described above, the fixation of the printed circuit board (3) to the chassis base (1) becomes unstable, and the reliability is significantly reduced. Further, stress may be applied to the solder (7) due to a difference in thermal expansion coefficient between the chassis base (1) and the printed circuit board (3) during a temperature cycle test in manufacturing an electronic tuner, and finally cracks may occur, which is a reliability factor. Sex is significantly reduced.

Therefore, as a concrete means for solving the above problems, a chassis base structure having a structure as shown in FIGS. 8 to 10 has been proposed. As shown in FIG. 8, a notch (8) is formed in the main part of the chassis base (1) corresponding to the earth land (5) of the printed circuit board (3) and crosses the peripheral end face of the printed circuit board (3). To provide a tongue (9). This tongue piece (9) has a narrow base end (9) which extends around the notch (8) of the chassis base (1).
a) and a wide free end portion (9b) extending from the base end portion (9a). As described above, with the printed circuit board (3) positioned and arranged in the chassis base (1), as shown in FIG.
As shown in FIG. 10, the free end portion (9b) of the tongue piece (9) is bent inward of the chassis base (1) to temporarily fix the printed circuit board (3). At this time, the free end portion (9b) of the tongue piece (9) inclined below the printed circuit board (3) is arranged to face the earth land (5) of the printed circuit board (3). If solder is supplied by solder dip processing in this state, a certain amount of solder (10) remains between the earth land (5) of the printed circuit board (3) and the free end portion (9b) of the tongue piece (9), and The earth land (5) and the free end portion (9b) of the tongue piece (9) are electrically and mechanically connected. As a result, the conductive pattern (6) of the printed board (3) is grounded, and the printed board (3) is permanently fixed to the chassis base (1).

In this chassis base structure, the tongue piece (9) acts to secure an appropriate amount of solder (10), so that the collective soldering process can be easily performed, and the printed circuit board (3) is very small on the chassis base (1). Since the tongue (9) is connected to the tongue (9) having a notch (8) on a part of the periphery, the tongue (9) can be moved a minute distance in the width direction and the longitudinal direction, and the temperature cycle in the electronic tuner manufacturing Even if stress is generated between the printed circuit board (3) and the chassis base (1) due to the difference in coefficient of thermal expansion during a test, the tongue (9) absorbs the strain and the connection by the solder (10) is impaired. There is no.

[Problems to be solved by the device]

By the way, in the above-mentioned chassis base structure, since the notch (8) and the tongue piece (9) are stamped and formed on the chassis base (1), it is difficult to bring the adjacent notches (8) and (8) close to each other. Difficult and its notches (8)
There was no choice but to increase the distance between the tongues (9) and (9) provided on (8). Therefore, the earth lands (5) of the printed circuit board (3) have been kept away from each other, but in recent years, the earth lands (5) have been forced to come close to each other due to the downsizing of devices.

[Means for Solving the Problems]

The present invention has been made in view of the above problems, and a technical means for solving the problems is tongue forming a notch that crosses the peripheral end surface of the printed circuit board in a frame-shaped frame base surrounding the printed circuit board. A piece is provided, the free end portion of the tongue piece is bent inward of the frame base to temporarily fix the printed circuit board, and the tongue piece and the outer peripheral portion of the printed circuit board are soldered and integrated. A plurality of tongue pieces whose end portions are formed shorter than the thickness of the printed circuit board are provided.

[Action]

By providing a plurality of tongue pieces in one notch, the earth lands formed on the outer peripheral edge of the printed circuit board can be brought close to each other.

〔Example〕

An embodiment of the chassis base structure according to the present invention will be described with reference to FIGS. 1 to 3.

The chassis base structure according to the present invention has a plurality of, in the embodiment, notches (11) formed in the frame base (1 ') surrounding the printed circuit board (3) across the peripheral end surface of the printed circuit board (3). Two tongues (12) (12) are provided corresponding to the earth lands (5) (5) of the printed circuit board (3). The tongue (12) has a cutout (1
(1) A narrow base end portion (12a) extending along the periphery of the base end portion (12a)
a) with a wide free end (12b) extending from
The length L of a) is formed to be shorter than the plate thickness of the printed circuit board (3), for example, 1 mm or less.

According to the said structure, two tongue pieces (12) (12) are provided in the notch (11).
Since the tongue pieces (12) and (12) adjacent to each other are provided, the distance between the adjacent tongue pieces (12) and (12) can be reduced, whereby the earth lands (5) and (5) can be formed close to the outer peripheral portion of the printed board (3). Further, since the length L of the base end portion (12a) of the tongue piece (12) is made shorter than the plate thickness of the printed circuit board (3), the opening area of the notch (11) can be reduced and the shielding property can be improved. Can be improved.

[Effect of device]

According to this invention, since the distance between adjacent tongues can be reduced, the ground lands of the printed circuit board can be made close to each other, and the size can be reduced, and the length of the base end of the tongue can be reduced. Since the thickness is smaller than the thickness of the printed circuit board, the opening area of the notch is reduced and the shield property is improved.

[Brief description of drawings]

1 to 3 are for explaining an embodiment of a chassis base structure according to the present invention, and FIG. 1 is an enlarged perspective view of an essential part showing a state before assembling a frame base of a printed circuit board, 2 is an enlarged perspective view of an essential part showing a state after the printed circuit board is assembled to the frame base, and FIG. 3 is a sectional view of the essential part of FIG. FIG. 4 is an exploded perspective view showing a concrete example of a conventional chassis base structure, FIG. 5 is a sectional view of the chassis base structure of FIG. 4, and FIG. 6 is a soldering portion of the chassis base structure of FIG. FIG. 7 is an enlarged bottom view of an essential part shown in FIG. 7, FIG. 7 is a side sectional view of FIG. 6, and FIG. 8 is an enlarged perspective view of an essential part showing a state before assembling a chassis base of a printed circuit board in another chassis base structure,
FIG. 9 is an enlarged perspective view of an essential part showing a state after assembly of FIG.
No. 10 is a sectional view of an essential part of FIG. (1 ') ... Frame base, (3) ... Printed circuit board, (11) ... Notch, (12) ... Tongue, (12a) ... Base end, (12b) ... Free end.

Claims (1)

[Scope of utility model registration request] 1. A frame base surrounding a printed circuit board is provided with a tongue by forming a notch that crosses a peripheral end surface of the printed circuit board, and the free end of the tongue is bent inwardly of the base. In the case where the board is temporarily fixed and the tongue piece and the outer peripheral portion of the printed board are soldered and integrated, a plurality of tongue pieces whose base end portion is formed shorter than the board thickness of the printed board is provided in the notch. Characteristic chassis base structure.