JPH0536304Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a chassis base mounting structure, and more particularly to a structure for assembling a printed circuit board to a chassis base used in an electronic tuner or the like.

BACKGROUND ART A chassis base mounting structure A used for an electronic tuner, etc., has a chassis base 1 made of metal in the shape of a substantially rectangular frame, and a plurality of electronic components 2, 2, . . . mounted thereon, as shown in FIGS. 3 and 4. The printed circuit board 3 is attached to the chassis base 1.
Position and store it inside. The printed circuit board 3 is positioned by inserting the printed circuit board 3 from one open end of the chassis base 1, and inserting the printed circuit board 3 into the chassis base 1 through projections 4, 4 provided at important points on the inner wall surface of the chassis base 1.
This is done by locking the outer periphery of the printed circuit board 3 with... As shown in FIGS. 5 and 6, a conductive pattern 5 for grounding is formed on the outer peripheral edge of one surface (lower surface in the figure) of the printed circuit board 3 positioned within the chassis base 1. By supplying solder 6 onto the pattern 5 manually or by a solder dip treatment, the conductive pattern 5 and the chassis base 1 are electrically and mechanically connected to ground the conductive pattern 5, and the printed circuit board 3 is connected to the chassis base 1. Fixed to 1.

Problems to be Solved by the Invention Incidentally, in the chassis base mounting structure A, the printed circuit board 3 is fixed to the chassis base 1, and the conductive pattern 5 of the printed circuit board 3 is fixed to the chassis base 1.
The amount of solder 6 supplied onto the conductive pattern 5 for grounding was not uniform, and some variation was likely to occur. In this way, the above solder 6
If there is variation in the supply amount, the fixation of the printed circuit board 3 to the chassis base 1 becomes unstable, and reliability is significantly reduced. Furthermore, during a temperature cycle test in the manufacture of an electronic tuner, there was a fear that stress would be applied to the solder 6 due to the difference in thermal expansion coefficients between the chassis base 1 and the printed circuit board 3, eventually causing a crack.

Therefore, as a specific means for solving the above problems, a chassis base mounting structure B having a structure as shown in FIGS. 7 to 9 has been proposed. This is the printed circuit board 3 as shown in FIG.
A tongue piece 8 is provided by forming a notch 7 that crosses the end surface of the printed circuit board 3 in a main part of the chassis base 1 corresponding to the grounding conductive pattern 5. The tongue piece 8 consists of a narrow base end 8a extending from the periphery of the notch 7 of the chassis base 1, and a wide free end 8b extending from the base end 8a. With the printed circuit board 3 positioned and arranged in the chassis base 1 as described above, the free end 8b of the tongue piece 8 is bent inward to the chassis base 1 as shown in FIGS. 8 and 9, and the printed circuit board 3 is removed. Temporarily fix. At this time, the free end portion 8b of the tongue piece 8 inclined below the printed circuit board 3 is arranged to face the grounding conductive pattern 5 of the printed circuit board 3. If solder is supplied by solder dip treatment in this state, the conductive pattern 5 of the printed circuit board 3 and the free end portion 8 of the tongue piece 8
A certain amount of solder 9 remains between the conductive patterns 5 and the free ends 8b of the tongues 8, thereby electrically and mechanically connecting them. As a result, the conductive pattern 5 of the printed circuit board 3 is grounded, and the printed circuit board 3 is permanently fixed to the chassis base 1. In addition, in the chassis base mounting structure B, it is necessary to bend the free end 8b of the tongue piece 8 inward to the chassis base 1, and in order to facilitate the bending of the tongue piece 8,
Chassis base mounting structure C shown in Figures and Figure 11
has also been proposed. As shown in FIG. 10, a notch 10 substantially parallel to the printed circuit board 3 is provided in the tongue piece 8 at a position corresponding to the peripheral edge portion m of the printed circuit board 3. This makes it possible to easily bend the free end 8b of the tongue piece 8 inward of the chassis base 1 along the notch 10, as shown in FIG. 11, with the printed circuit board 3 positioned within the chassis base 1. becomes.

However, in the chassis base mounting structures B and C in which the printed circuit board 3 is temporarily fixed to the chassis base 1 by the tongue piece 8 as described above, and the tongue piece 8 is integrated with the outer peripheral part of the printed circuit board 3 by soldering, the tongue piece 8 is 8 inwardly into the chassis base 1, a portion of the tongue 8 is bent by a bending force that presses the free end 8b of the tongue 8 inward around the base end 8a around the root portion of the base end 8a. Stress is applied to the peripheral edge portion m of the printed circuit board 3, which is in contact with the printed circuit board 3.
In this case, the peripheral edge portion m of the printed circuit board 3
At the upper position corresponding to the tongue piece 8 formed by the notch 7
3, there is no protrusion 4 for positioning the printed circuit board (see FIGS. 3 and 4). As a result, the stress acts obliquely upward inside the chassis base 1, causing the problem that the outer peripheral portion of the printed circuit board 3 bends upward, causing the printed circuit board 3 to warp.

Means for Solving the Problems The present invention provides a tongue piece that extends inward from one end of a frame-shaped metal chassis, has a bent middle portion, extends parallel to the inner wall of the chassis, and has an embossed tip. and a printed circuit board having a tongue insertion hole at a position corresponding to the tip of the tongue, the tongue being inserted into the insertion hole and fixed by soldering. .

Function: The tongues of the frame-shaped chassis base and the printed circuit board are inserted in the same direction, and the chassis base is placed on and supported by the printed circuit board and temporarily held by the embossing.

Embodiment An embodiment of the chassis base mounting structure according to the present invention will be described below with reference to FIGS. 1 and 2.
The same reference numerals as in FIGS. 4 and 5 indicate the same parts. In the figure, 1 is a nearly rectangular chassis base made of metal, 3 is a printed circuit board on which a plurality of electronic components are mounted, and 11 is a tongue piece extending inward from one end of the chassis base 1, and one end of the chassis base 1 is printed. A narrow base end 11a is cut out by a certain width according to the storage height of the board 3 and extends inward from the periphery of the notch 12 into the chassis, and a narrow base end 11a is bent inward from the base end 11a toward the chassis axis. The bent part 1 has a wide tip and has an embossment 11c in the center.
1b. 13 is a tongue insertion hole provided on the printed circuit board 3 at a position corresponding to the bent portion 11b of the tongue 11.

According to the above configuration, the chassis base mounting structure D of the present invention has a printed circuit board 3 mounted on the chassis base 1.
When storing and arranging the tongue piece 11, first insert the bent part 11b of the tongue piece 11 into the tongue piece insertion hole 13 from the mounting side of the electronic component 2 (see FIGS. 3 and 4) of the printed circuit board 3.
Insert into. Then, the printed circuit board 3 is locked by the base end 11a and the height position is set, and the embossing 11c of the bent part 11b is press-fitted and engaged with the tongue insertion hole 13, and a solder dip is formed from the bottom surface, which will be described later. When doing so, make sure that the chassis base 1 does not lift up. In this state, the chassis base 1 is permanently fixed to the printed circuit board 3 by soldering the bent portion 11b together with the electronic component 2 using a solder dip using jet soldering, for example. At this time, there is no need to control the solder supply amount, and as shown in Figure 2, the solder
4 is attached to the periphery of the bent portion 11b, so the bonding area becomes large. Also, as in the past, stress due to the difference in thermal expansion coefficient between the chassis base 1 and the printed circuit board 3 is applied to the narrow base end 11a of the tongue piece 11 during temperature cycle tests in electronic tuner manufacturing.
This prevents cracks from occurring in the solder 14.

Effects of the Invention According to the chassis base mounting structure according to the present invention, the tongue piece extends inward from one end of the chassis base and has a tip portion bent in the chassis axis direction.
Since the tongue piece is inserted into the insertion hole of the printed circuit board and fixed by soldering, the tongue piece does not press the outer periphery of the printed circuit board during temporary fixing until soldering, thereby eliminating deformation of the printed circuit board. In addition, the number of man-hours required for temporarily fixing the printed circuit board is reduced, simplifying the work, and the solder joint area of the tongue piece is enlarged to stably fix the tongue to the printed circuit board, thereby improving reliability.

[Brief explanation of the drawing]

Figures 1 and 2 are for explaining one embodiment of the present invention; Figure 1 is an enlarged perspective view of the main parts showing the state before the printed circuit board is assembled to the chassis base;
The figure is an enlarged plan view of main parts showing the state after the printed circuit board is assembled to the chassis base, Figure 3 is an exploded perspective view showing a specific example of the chassis base mounting structure, and Figure 4 is a sectional view of the chassis base mounting structure of Figure 3. , FIG. 5 is an enlarged bottom view of the main parts showing the soldering part of the chassis base mounting structure shown in FIG. 3, FIG. 6 is a side sectional view of FIG. 5, and FIG. Figure 8 is an enlarged perspective view of the main parts showing the state before the chassis base is installed, Figure 8 is an enlarged perspective view of the main parts showing the state after assembly of Figure 7, Figure 9 is a sectional view of Figure 8, and Figure 10 is FIG. 7 is an enlarged perspective view of a main part showing the chassis base mounting structure with a notch provided in the tongue before assembly, and FIG. 11 is a side sectional view showing the state after assembly of FIG. 10. 1... Chassis base, 3... Printed circuit board,
11... tongue piece, 13... tongue piece insertion hole.

Claims (1)

[Scope of utility model registration request] A chassis base having a tongue extending inward from one end of the frame-shaped metal chassis, having a bent intermediate portion, a tip extending parallel to the inner wall of the chassis, and having an embossed tip; and a tip of the tongue. 1. A chassis base mounting structure comprising: a printed circuit board having a tongue insertion hole at a corresponding position; the tongue is inserted into the insertion hole and fixed by soldering.