JPH0711520Y2 - Printed wiring board fixing structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a structure for fixing a printed wiring board to a frame that also serves as a shield plate.

(B) Conventional technology When the printed wiring board (PCB) mounted on the frame is divided into multiple circuit blocks, such as high-frequency equipment such as CATV tuners, the grounding performance and shielding of each circuit block are important. To be done.

Therefore, conventionally, as shown in FIG. 6, the PCB 3 is fitted into the frame 1 having the partition plate 2 for dividing the individual circuit blocks, and the rear shield plate 4 is fitted into the predetermined circuit block. Electrical connection between the earth land 6 of the PCB 3 and the frame 1 is achieved through the projections 5 formed on the frame 1 and the rear shield plate 4, and the frame 1 is provided with a function as a shield plate. That is, the rear shield plate 4 is provided with the claws 7 for soldering.
Was soldered to the frame 1, the claws 7 were soldered to the earth land 6, and the projections 5 provided on the frame 1 and the partition plate 2 were soldered to the earth land 6.

Such a high frequency device A is assembled in the following procedure.
That is, as shown in FIG. 7 and FIG. 8, the PCB 3 is press-fitted into the frame 1 to bend over the PCB 3 so as to pass over the protrusion 5, so that the PCB 3 is engaged with the engaging portion 8 formed in the frame 1.
At the same time as it is locked to, it is sandwiched between the engaging portion 8 and the projection 5 and temporarily fixed. After that, the rear shield plate 4 is press-fitted into the frame 1 and temporarily fixed. Then, it is immersed in the solder bath 9 as shown in FIG. As a result, the soldered portions, that is, the rear shield plate 4, the frame 1 and the partition plate 2, the claws 7 of the rear shield plate 4 and the earth lands 6, the protrusions 5 and the earth lands 6 and the like are simultaneously soldered. Note that the electronic components 10 and the like are previously attached to the PCB 3, and these electronic components 10 are also soldered to the predetermined soldering lands of the PCB 3 at the same time when they are immersed in the solder bath.

(C) Problems to be Solved by the Invention Since the protrusions 5 need to have a large overlapping area with respect to the earth land 6 to maintain reliability of solderability, the protrusion width of the protrusions 5 must be relatively large. In addition, the number is required to be at least the number of the earth lands 6 formed in each circuit block of the PCB 3. Therefore, PCB3
The PCB 3 had to be bent relatively large when the was pressed into the frame 1, which caused defects such as peeling of the circuit pattern formed on the PCB 3. In particular, the bending width was large at the central portion of the PCB 3, and defects such as peeling of the earth land 6 at that portion were likely to occur. In order to suppress the occurrence of such a defect, the protrusion width of the protrusion 5 may be made small. However, when this is done, the overlapping area of the protrusion 5 and the earth land 6 becomes narrow, and the reliability of solderability deteriorates. However, solder defects are likely to occur.

Further, in the past, although the frame 1 and its partition plate 2 are also used as a shield frame, an auxiliary plate such as a rear shield plate 4 is separately used to separate the earth land 6 from the frame 1 and the partition plate 2. It is necessary to establish electrical continuity, and the rear shield plate 4 is likely to cause deformation and variations in press-fitting accuracy when press-fitting into the frame 1. Therefore, the soldering claw 7 and the earth land 6 are soldered together. Sometimes it was loose.

This invention was made in view of the above circumstances.By devising the structure of the frame, the PCB can be fitted into the frame without much deformation, and the rear shield does not deteriorate the shield performance. An object of the present invention is to provide a fixing structure for a PCB that can eliminate the need for an auxiliary plate such as a plate.

(D) Means for Solving the Problems In the PCB fixing structure according to the present invention, a printed wiring board is fitted into a frame which also has a partition plate inside the outer frame and which also serves as a shield plate. A plurality of claw pieces divided from the adjacent portion are formed at a plurality of positions of the partition plate which is standing up by,
A printed wiring formed on the claw piece, the outer frame, and the partition plate, the claw piece being bent in an inclined state in which the vicinity of the base of the claw piece is almost in contact with the printed wiring board and is gradually separated from the partition plate from the vicinity of the base to the tip. The printed wiring board is sandwiched by an engaging portion that supports the board, and at least a part of the claw pieces faces an earth land of the printed wiring board.

(E) Action According to this configuration, the PC is in a state where the claw is not bent.
Since B can be fitted into the frame, doing so allows the PCB to fit into the frame without bending. Further, since the PCB fitted in the frame is pinched and fixed (temporarily fixed) by the claw pieces bent after the fitting and the engaging portions of the frame, the frame is provided with the protrusion described in the conventional example. It is not always necessary, or even if it is necessary, the number of protrusions can be reduced compared to the past, and since the protrusion corresponding to the earth land at the center of the PCB can be omitted, the PCB is press-fitted into the frame. Even if it is necessary, it is not necessary to bend the circuit pattern so that it peels off.

(F) Embodiment FIG. 1 is a perspective view of a high frequency device A employing a PCB fixing structure according to an embodiment of the present invention. The frame 1 of the high frequency device A also serves as a shield plate, and is provided with an outer frame 11 and a partition plate 12 for partitioning individual circuit blocks of the PCB 2. The projection 5 is formed at a proper position on the outer frame 11, while the claw pieces 14 divided from the adjacent portion by the slit-shaped grooves 13 are formed at a plurality of positions on the partition plate 12. The root portion 14a of 14 is the fifth
It is thinned by the groove 15 shown in the figure.

The PCB3 has slit-like narrow grooves that fit into the partition plate 12 above.
Circuit patterns such as 16 and earth land 5 are formed. The earth lands 6 include those corresponding to the claw pieces 14 and those corresponding to the protrusions 5.

As shown in FIG. 2 and FIG. 3, when assembling the PCB 3 into the frame 1, the PCB 3 is bent and press-fitted into the frame 1 to overcome the protrusion 5 and the PCB 3 is engaged with the frame 1. At the same time as engaging with the portion 8, it is sandwiched between the engaging portion 8 and the protrusion 5. At this time, the nail piece
14 is unfolded. Further, since the protrusion 5 is provided only on the outer frame 11 of the frame 1 and not on the partition plate 12, the deflection width of the PCB is larger than that of the conventional one in which the partition plate is also provided with the protrusion. Is less,
As a result, the risk of peeling the circuit pattern of the PCB is reduced. In particular, since there is no protrusion in the central part where the bending width of the PCB is the largest, there is almost no fear of peeling the circuit pattern. Such an action is similarly exhibited even when the protrusion width of the protrusion 5 provided on the outer frame 11 is increased to increase the overlapping area with the earth land 6.

The PCB3 assembled on the frame 1 as described above
As shown in FIG. 4, the claw piece 14 is bent from the root portion 14a thereof into a tilted state, and the claw piece 14 and the engaging portion 8 allow the PCB 3 to move.
Hold and fix (temporarily fix). In this case, the claw piece 14 corresponding to the earth land 6 is bent toward the earth land 6 side to face the earth land 6, thereby preparing for the next soldering step. Note that the sandwiching state of the PCB 3 between the claw piece 14 and the engaging portion 8 does not necessarily have to be fixed so that the PCB 3 does not move, but the bending angle of the claw piece 14 is made shallow to allow the PCB 3 to engage with the claw piece 14. It may be in a state of slightly moving with the joint portion 8, and the present invention also includes such a state.

Since the root portion 14a of the claw piece 14 is thinned as described above, the claw piece 14 can be formed by simply pressing the inclined surface 21 of the projecting jig 20 against the tip of the claw piece 14 as shown in FIG. Is the root part
Easy and sure bending from 14a with high accuracy. Further, if the level of the groove 15 for thinning the root portion 14a of the claw piece 14 is set within the thickness range of the PCB 3, when the claw piece 14 is bent, the PCB is engaged by the claw piece 14. The joint portion 8 is strongly pressed and more securely fixed. By immersing the frame 1 on which the PCB 3 is temporarily fixed in the solder bath in this manner, the earth land 6 and the claw pieces 14 or the protrusions 5 are reliably soldered, and a reliable shield property is secured. At the same time, the electronic components previously attached to the PCB 3 are also soldered to the predetermined soldering lands.

In this embodiment, the projection 5 is provided on the outer frame 11 of the frame 1. However, the projection 5 is not essential, and instead of the projection 5, a claw piece having the same structure as the claw piece 14 may be formed. ,
This will allow the PCB3 to fit into the frame 1 without bending.

(G) Effect of the Invention According to this invention, the PCB can be fitted into the frame without being press-fitted, or even if it is necessary to press-fit, the PCB does not need to be bent so much. With this, defects such as separation of circuit patterns such as earth lands do not occur.

In addition, the PCB fitted in the frame is not only securely fixed by being pinched by the claw pieces bent after the fitting and the engaging portions of the frame, but also because the claw pieces face the earth land, By soaking in the solder bath, reliable soldering is performed, and the solder is not loose. Therefore, there is an effect that reliability of solderability between the earth land and the frame is improved and a reliable shield property is exhibited, and accordingly, an auxiliary plate such as a rear shield plate becomes unnecessary. Also, near the base of the claw piece provided on the partition plate is almost in contact with the PCB, and since it is bent in a tilted state that gradually separates from the partition plate from the vicinity of the root to the tip, part of the partition plate is used as a claw piece. Almost no recesses or gaps are formed in the partition plate due to the bending, and this has the effect of reliably shielding between the sections of the PCB. Also, because the PCB is sandwiched between the claw pieces and the engaging portion provided on the partition plate so that the PCB is held inside the frame, even if the PCB is relatively large, the PCB will not bend. There is an effect that it is securely fixed in the frame without peeling. Further, it is not necessary to provide the outer frame with the claw piece, and since the concave portion and the gap due to the bending of the claw piece are not formed in the outer frame, the shield property of the outer frame is not impaired.

[Brief description of drawings]

FIG. 1 is a perspective view of a high-frequency device adopting a PCB fixing structure according to an embodiment of the present invention, FIGS. 2 and 3 are sectional views showing a procedure of assembling the PCB to a frame, and FIG. Fig. 5 is a cross-sectional view of the PCB sandwiched between the mating part, Fig. 5 is a perspective view showing the claw pieces and the jig, and Fig. 6 is a conventional PCB
FIG. 7 is a perspective view of a high-frequency device adopting the fixing structure of FIG. 7, FIGS. 7 and 8 are sectional views showing a procedure for press-fitting a PCB into a frame, and FIG. 9 is an explanatory view of a soldering process. 1 ... frame, 3 ... PCB (printed wiring board), 6
...... Earthland, 8 ...... engagement part, 14 ...... claw pieces.

Claims (1)

[Scope of utility model registration request] 1. A printed wiring board is fitted into a frame which also has a partition plate inside an outer frame and which also serves as a shield plate, and a portion adjacent to a plurality of the partition plates rising inside the printed wiring board. A plurality of claw pieces divided from the claw pieces are formed, and the claw pieces bent in a tilted state in which the vicinity of the base of the claw pieces is almost in contact with the printed wiring board and gradually separated from the partition plate from the vicinity of the base to the tip. The printed wiring board is sandwiched by an engaging portion that supports the printed wiring board formed on the outer frame and the partition plate, and at least a part of the claw pieces is used as an earth land of the printed wiring board. A printed wiring board fixing structure characterized by facing each other.