JP3883447B2 - Instrument board fixing structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an instrument board fixing structure for fixing a board incorporated in an automobile instrument such as a speedometer in a case of the instrument.
[0002]
[Prior art]
When a board with electronic components mounted is installed in an automotive instrument such as a speedometer, the board is fixed in the case by screwing a screw through a hole in the board into a screw boss protruding from the inner surface of the case. It is common to use a method to do this.
[0003]
A substrate fixing structure in a conventional instrument will be described with reference to FIGS.
As shown in FIG. 6, a plurality of screw bosses 2 are appropriately provided on the inner surface of a synthetic resin case 1 in which a substrate 4 on which electronic components are mounted is incorporated.
Then, when fixing the substrate 4 to the case 1, as shown in FIG. 7, with the holes 5 provided in the substrate 4 placed on the screw bosses 2, the screws 3 are placed from above. By screwing using a screwdriver or the like, the screw 3 penetrating the hole 5 is fastened to the pilot hole 2 a of the screwing boss 2, and the substrate 4 is fixed to the case 1.
[0004]
[Problems to be solved by the invention]
By the way, the method of fixing the substrate 4 to the case 1 using the screws 3 as described above requires an operation of screwing the screws 3 into the screwing bosses 2 one by one, so that the assembly is very troublesome.
[0005]
Further, when the screw 3 is fastened to the screw boss 2, the depth of the lower hole 2a for engaging with the effective screw portion of the screw 3 is required to some extent. Therefore, it is necessary to set the height of the portion (tip surface) that receives the substrate 4 to be equal to or greater than the effective screwing length of the screw 3 in the screwing boss 2, and as a result, the thickness of the entire instrument increases. As a result, there is a problem that the whole instrument is thinned.
Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide an instrument board fixing structure capable of realizing a simplified assembly process and an overall thinning.
[0006]
[Means for Solving the Problems]
The above object of the present invention is a substrate fixing structure for an instrument that fixes the substrate to the inner surface of the case by forcibly press-fitting a press-fitting boss projecting from the inner surface of the case into the fixing hole formed in the substrate. There,
The instrument is fixed to a board, wherein a peripheral wall defining a sealed space around the press-fitting boss is projected on the inner surface of the case so as to surround the press-fitting boss when a tip part abuts on the board. Achieved by structure.
[0007]
According to the above configuration, the substrate can be fixed to the case simply by forcibly pressing the press-fitting boss into the fixing hole of the substrate.
Therefore, a troublesome process such as tightening a screw is not necessary, and the assembly process can be simplified. In addition, since it is not necessary to make a screwing hole in the press-fitting boss, the height of the press-fitting boss can be made lower than that of the screwing boss.
[0008]
Furthermore, because it is fixed by forced press-fitting, by setting the fit between the press-fitting boss and the fixing hole with a tight fit, the board can be fixed to the case without rattling, due to vibration. Troubles such as damage to parts in the instrument and generation of abnormal noise can be solved.
[0009]
In addition, since the peripheral wall defining the sealed space around the press-fitting boss is projected so as to surround the press-fitting boss when the tip part abuts against the substrate, the press-fitting boss is forced to the fixing hole of the substrate. The shavings generated when press-fitting into the case are not scattered in the case.
Therefore, there is no possibility that the scraps generated during press-fitting will wrap around the front of the instrument and cause defects in appearance, or adversely affect the interior parts (intrusion into movable parts, etc.).
[0010]
Preferably, the press-fitting boss comprises a columnar press-fitting part protruding on the base and a truncated cone-shaped insertion part formed at the tip of the press-fitting part, and on the outer peripheral surface of the press-fitting part. Are formed with a plurality of rib protrusions extending along the axial direction.
In this case, since the frustoconical insertion portion is provided at the tip of the press-fitting boss, the press-fitting boss can be easily inserted into the fixing hole. Also, when the press-fitting boss is press-fitted, the rib protrusions formed on the outer peripheral surface of the press-fitting part are press-fitted while rubbing against the periphery of the fixing hole, so the press-fitting resistance is smaller than when the entire circumference of the press-fitting part is rubbing. , Easy to press fit.
[0011]
The press-fitting boss is configured as a polygonal column projecting on the base, and the polygonal column has a cross section in which a plurality of ridges are radially formed.
In this case, when the press-fitting boss is press-fitted, the protrusion is press-fitted while rubbing against the periphery of the fixing hole, so that the press-fitting resistance is smaller than when the entire circumference of the press-fitting part is rubbing, and the press-fitting is easy.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
1 is an exploded perspective view for explaining a board fixing structure of an instrument according to an embodiment of the present invention, FIG. 2 is an enlarged perspective view of a portion II in FIG. 1, and FIG. 3 is a fixing hole of the board shown in FIG. It is a longitudinal cross-sectional view for demonstrating the press injection process of the press injection boss | hub with respect to.
[0013]
A case 11 made of synthetic resin shown in FIG. 1 is a case of a speedometer unit which is an automobile instrument, and a substrate 10 on which electronic components are mounted is incorporated.
A plurality of press-fitting bosses 12 are appropriately projected on the inner surface of the case 11 into which the substrate 10 is incorporated. By forcibly press-fitting the press-fitting bosses 12 into the fixing holes 15 formed in the substrate 10, The substrate 10 is fixed to the inner surface of the case 11.
[0014]
As shown in FIG. 2, the press-fitting boss 12 includes a cylindrical press-fitting part 12b projecting from the upper surface of the base part 12a, and a truncated cone-shaped insertion part formed continuously at the tip of the press-fitting part 12b. 12c.
The base portion 12a is configured as a cylindrical body having a diameter larger than that of the press-fitting portion 12b, and an upper end surface of the base portion 12a is a contact surface that contacts and positions the substrate 10.
[0015]
Four rib protrusions 12d extending along the axial direction are formed on the outer peripheral surface of the press-fit portion 12b at equal intervals along the circumferential direction. And the upper end part of these rib protrusion 12d is formed so that it may continue without a level | step difference to the conical surface of the said insertion part 12c.
The apparent outer diameter of the press-fit portion 12b including these rib protrusions 12d is slightly larger than the inner diameter of the fixing hole 15.
[0016]
Further, a cylindrical peripheral wall 13 protrudes from the inner surface of the case 11 so as to surround each press-fitting boss 12. The distal end portion of the peripheral wall 13 is set to the same height as the upper end surface of the base portion 12a, and comes into contact with the substrate 10 positioned in contact with the upper end surface of the base portion 12a. A sealed space 16 can be defined around the periphery.
[0017]
Next, the press-fitting process of the press-fitting boss 12 into the fixing hole 15 of the substrate 10 will be described with reference to FIG.
When the substrate 10 is assembled to the case 11, the fixing holes 15 of the substrate 10 are pressed toward the corresponding press-fitting bosses 12, and the press-fitting bosses 12 are inserted into the fixing holes 15. At this time, since the truncated cone-shaped insertion portion 12 c provided at the tip of the press-fitting boss 12 guides the insertion of the fixing hole 15, the press-fitting boss 12 can be easily inserted into the fixing hole 15.
[0018]
The press-fitting boss 12 is forcibly press-fitted into the fixing hole 15 while the rib projection 12d of the press-fitting portion 12b rubs against the inner peripheral edge of the fixing hole 15, and the inner peripheral surface of the fixing hole 15 and the rib The substrate 10 is fixed to the case 11 without rattling by friction with the outer peripheral surface of the protrusion 12d.
Therefore, troubles such as damage to parts in the instrument and generation of abnormal noise due to vibration can be avoided.
At this time, since the four rib projections 12d projecting at equal intervals along the circumferential direction on the outer peripheral surface of the press-fit portion 12b rub against the inner peripheral edge of the fixing hole 15, the entire circumference of the press-fit portion 12b. The press-fit resistance becomes smaller than when the two rub against each other, and the press-fit becomes easier.
[0019]
As described above, according to the board fixing structure of the meter according to the present embodiment, the board 10 can be fixed to the case 11 only by forcibly press-fitting the press-fitting boss 12 into the fixing hole 15 of the board 10.
Therefore, a troublesome process such as tightening a screw is not necessary, and the assembly process can be simplified. Further, since it is not necessary to make a screwing hole in the press-fitting boss 12, the height of the press-fitting boss 12 can be made lower than that of the screwing boss 2 shown in FIG. This can contribute to the thinning of the entire instrument.
[0020]
When the press-fitting boss 12 is forcibly press-fitted into the fixing hole 15 as described above, the press-fitting boss 12 or the scraped scrap 20 of the substrate 10 is removed from the rubbing portion as shown in FIG. May occur. However, a peripheral wall 13 protrudes around the press-fitting boss 12, and the shaving residue 20 falls into the peripheral wall 13 and is stored.
[0021]
As shown in FIG. 3B, in the state where the press-fitting boss 12 is completely press-fitted into the fixing hole 15, the tip of the peripheral wall 13 abuts against the substrate 10 to seal the inside of the peripheral wall 13, Since the sealed space 16 is defined around the press-fitting boss 12, the scrap residue 20 accommodated in the sealed space 16 is not scattered in the case 1 outside the peripheral wall 13.
[0022]
Therefore, according to the board fixing structure of the meter according to the present embodiment, the shavings 20 generated at the time of press-fitting rotate around the front of the instrument despite the press-fitting of the press-fitting boss 12 into the fixing hole 15 of the board 10. There is no risk of troubles such as appearance defects or adverse effects on interior parts (intrusion into moving parts, etc.).
[0023]
In addition, the structure of the press-fitting boss, the fixing hole, and the peripheral wall in the substrate fixing structure of the instrument of the present invention is not limited to the structure of the above-described embodiment, and various configurations can be adopted based on the spirit of the present invention. Needless to say.
For example, in the above embodiment, four rib protrusions 12d are provided at regular intervals along the circumferential direction on the outer peripheral surface of the press-fit portion 12b. However, like the press-fit boss 12B shown in FIG. Two rib protrusions 12d may be provided on the outer peripheral surface of the press-fitted portion 12b at regular intervals along the circumferential direction. It can be projected.
[0024]
The shape of the press-fitting boss of the present invention may be any shape as long as it can exert an effective engaging action with respect to the fixing hole 15 of the substrate 10.
For example, the press-fitting boss 22 shown in FIG. 5 is configured as a polygonal column 22b protruding on the base 22a, and the polygonal column 22b has a cross-shaped shape in which four ridges 22c are radially formed. It has a cross section.
[0025]
Also in this case, since each protrusion 22c can be forcibly press-fitted while being rubbed against the inner peripheral edge of the fixing hole 15, it can be easily press-fitted with a small press-fitting resistance. A guide taper portion 22d for facilitating insertion into the fixing hole 15 is provided at the tip corner portion of each protrusion 22c.
[0026]
In the above-described embodiment, the case where the substrate 10 is fixed to the case 11 of the speedometer unit has been described as an example. However, the present invention is not limited to an automobile instrument such as a speedometer, and the substrate fixing structure of various instruments is used. Of course, it can be applied.
[0027]
【The invention's effect】
As described above, according to the instrument substrate fixing structure of the present invention, the substrate can be fixed to the case only by forcibly pressing the press-fitting boss into the fixing hole of the substrate.
Therefore, a troublesome process such as tightening a screw is not necessary, and the assembly process can be simplified. Further, since it is not necessary to make a hole for screwing in the press-fitting boss, the height of the press-fitting boss can be made lower than that of the screwing boss, which contributes to a reduction in the thickness of the entire instrument.
[0028]
Furthermore, because it is fixed by forced press-fitting, by setting the fit between the press-fitting boss and the fixing hole with a tight fit, the board can be fixed to the case without rattling, due to vibration. Troubles such as damage to parts in the instrument and generation of abnormal noise can be solved.
[0029]
In addition, since the peripheral wall defining the sealed space around the press-fitting boss is projected so as to surround the press-fitting boss when the tip part abuts against the substrate, the press-fitting boss is forced to the fixing hole of the substrate. The shavings generated when press-fitting into the case are not scattered in the case.
Therefore, even though the press-fitting boss is forcibly pressed into the fixed hole, the shavings generated during press-fitting can enter the front of the instrument, causing defects in the appearance, and adverse effects on interior parts (to the moving parts). There is no risk of trouble such as intrusion of
[Brief description of the drawings]
FIG. 1 is an exploded perspective view for explaining a board fixing structure of a meter according to an embodiment of the present invention.
FIG. 2 is an enlarged perspective view of a portion II in FIG.
3 is a longitudinal sectional view for explaining a press-fitting process of a press-fitting boss with respect to a fixing hole of a substrate shown in FIG. 1;
4 is an enlarged perspective view showing a modification of the press-fitting boss shown in FIG. 2. FIG.
FIG. 5 is an enlarged perspective view of a press-fitting boss according to another embodiment of the present invention.
FIG. 6 is an exploded perspective view for explaining a substrate fixing structure of a conventional instrument.
7 is a longitudinal sectional view of the screwing boss shown in FIG. 6. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Board | substrate 11 Case 12 Press-fit boss 12a Base part 12b Press-fit part 12c Insertion part 12d Rib protrusion 13 Peripheral wall 16 Sealed space 20 Cutting residue

Claims (3)

A board fixing structure of the instrument for fixing the board to the inner surface of the case by forcibly press-fitting a press-fitting boss projecting on the inner face of the instrument into a fixing hole drilled in the board,
A fixed board for an instrument, wherein a peripheral wall defining a sealed space around the press-fitting boss is projected on the inner surface of the case so as to surround the press-fitting boss when a tip part abuts on the board. Construction. The press-fitting boss comprises a columnar press-fitting portion protruding on the base and a frustoconical insertion portion formed at the tip of the press-fitting portion, and the outer peripheral surface of the press-fitting portion has an axial direction The board fixing structure for an instrument according to claim 1, wherein a plurality of rib protrusions extending along the line are formed. The press-fitting boss is configured as a polygonal column projecting on a base, and the polygonal column has a cross section in which a plurality of protrusions are radially formed. Instrument board fixing structure.

Images