JP2973285B2 - Fixing structure of film and mounting plate and fixing structure of terminal of flexible board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for fixing a film to a mounting plate and a structure for fixing a terminal portion of a flexible substrate mounted on the mounting plate.

[0002]

2. Description of the Related Art Conventionally, various electronic components such as rotary variable resistors have been required to be thin and small.

FIG. 7 is an exploded perspective view showing a conventional rotary variable resistor of this kind. As shown in the figure, the conventional rotary variable resistor is configured such that a flexible substrate 90 is mounted on a thin metal mounting plate 80, and a knob 100 is rotatably mounted thereon.

[0004] Here, a metal terminal strip 93 is fixed on an end of each pattern 91 provided on the flexible substrate 90 to form a terminal section 96.

[0005] By inserting a knob support projection 83 provided at the center of the mounting plate 80 into a hole 95 provided at the center of the flexible board 90, the flexible board 90 is inserted.
Is mounted on the mounting plate 80, and the two tongue-shaped locking projections 85, 85 provided on the outer periphery of the mounting plate 80 are bent toward the upper surface side of the terminal portion 96 of the flexible substrate 90, thereby forming the terminal portion 96. Is fixed. Note that one of the locking projections 85
Is shown by a dotted line.

When the tip of the knob support projection 83 of the mounting plate 80 is inserted into the hole 101 provided at the center of the knob 100 and the tip is swaged, the rotary variable resistor 80 is completed.

When the knob 100 is rotated, a slider (not shown) attached to the lower surface of the knob 100 slides on each pattern 91, and the resistance between the metal terminal pieces 93 changes.

The reason why the both ends of the terminal portion 96 of the flexible substrate 90 are fixed using the locking projections 85 of the mounting plate 80 is as follows.

That is, since the mounting plate 80 and the flexible substrate 90 are separate bodies, unless the terminal portion 96 is fixed to the mounting plate 80, the rotary variable resistor is mounted on another substrate (not shown). Then, when an attempt is made to solder between the pattern of the other substrate and each metal terminal piece 93, the terminal portion 96 floats from the mounting plate 80, or the flexible substrate 90 bends due to heat during solder reflow. Sisters,
Because of these, there is a possibility that the soldering cannot be performed reliably.

[0010]

However, in the above-mentioned conventional example, the locking projection 85 and the locking protrusion 85 are further provided on the portion of the flexible board 90 on which the metal terminal strip 93 is provided.
85, the locking projections 85, 85
The thickness of the terminal portion 96 is increased by the thickness (about 0.3 mm).

Since the knob 100 is located on the bent locking projection 85, the rotary variable resistor 80
The overall thickness is increased.

Conversely, if the thickness is to be reduced, the portions of the flexible board 90 where the metal terminal pieces 93 do not exist at both ends of the terminal portion 96 are so arranged that the knob 100 is not located on the bent locking projections 85, 85. It is necessary to extend left and right, and fix both ends of the extended terminal portion 96 by locking projections 85, 85.

However, with this configuration, the size of the rotary variable resistor as a whole increases, which hinders downsizing.

By the way, in addition to the fixing structure, the mounting plate 80
A method is also conceivable in which an upwardly-facing protrusion is provided, and the protrusion is fixed to portions of the flexible substrate 90 at both ends of the terminal portion 96 where the metal terminal pieces 93 do not exist by pressing. According to this method, the height of the projections can be reduced to the thickness of the portion of the terminal portion 96 where the metal terminal pieces 93 are provided, and the area of the projections does not increase.

However, in the case of this fixing structure, a mechanical impact force called a press is applied to the pattern 91 and the metal terminal strip 93.
Since the film is added to the portion very close to the portion where the metal terminal piece 93 is connected, the film constituting the terminal portion 96 is strongly pulled, and the electrical connection between the metal terminal piece 93 and the pattern 91 is broken, which may result in poor conduction. Was.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a structure for fixing a film and a mounting plate, which can be easily made thin and small, and in which there is no possibility of poor conduction of terminals. An object of the present invention is to provide a terminal portion fixing structure for a flexible substrate.

[0017]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention comprises a film made of a thermoplastic synthetic resin, and a mounting plate made of a metal plate. A small protrusion protruding from the film is provided, and when the film is placed on the mounting plate, a portion of the film contacting the small protrusion is opposite to a portion of the film contacting the small protrusion.
Heated by ultrasonic vibration of ultrasonic horn in contact with the side
The small projections are pressed by pressing
And insert the ultrasonic horn into the
Abuts the tip of the small projection protruded into the
By fixing the two
The fixed structure of the lum and the mounting plate was constructed. Also, the present invention
Put the desired pattern on the top surface of the plastics
And a metal terminal strip at the end of the pattern.
From a flexible board fixed as a terminal part and a metal plate
And a mounting plate comprising:
Place it on top and attach the terminal part of the flexible board
Terminal part fixing structure of flexible substrate fixed to the board
In the above, the terminal portion of the flexible board of the mounting plate
Protrudes in the direction of the flexible substrate
A small projection is provided, and the flexible substrate is placed on the mounting plate.
When the film is placed on the terminal,
Abutting against the opposite side of the portion where the small projection of the film abuts
Was heated and softened by the ultrasonic vibration of the ultrasonic horn
By pressing in the state, the small projection is placed in the film of the terminal part.
And place the ultrasonic horn in the film.
Crushing the tip of the small projection by contacting the tip of the small projection
By fixing between the two
The terminal part fixing structure of the metal substrate was constructed.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an exploded perspective view showing a rotary variable resistor 10 according to one embodiment of the present invention.

As shown in FIG.
0 is the flexible board 30 and the knob 5 on the mounting plate 20.
0 is attached. Hereinafter, each component will be described.

The mounting plate 20 is provided with a support projection 21 which is formed in a cylindrical shape and protrudes substantially at the center of a thin metal plate (for example, 0.3 mm in thickness). A stopper 23 is provided, which is bent toward, and a support table 25 is provided at four locations around the stopper 23 so that the surface of the mounting plate 20 is cut and raised in a trapezoidal shape.

Small projections 27, 27 are provided on both ends of a portion of the mounting plate 20 on which a terminal portion 39 of the flexible substrate 30 described below is mounted so as to protrude upward (ie, toward the flexible substrate 30). Is provided.

The small projections 27 constitute a terminal portion 39 of the flexible substrate 30 whose height is described below.
The thickness is slightly shorter than the combined thickness of the films 31, 45, and the leading edges 27a, 27a are sharpened sharply.

Next, as shown in FIG.
No. 0 is provided with a through-hole 33 in the center of a film 31 made of thermoplastic synthetic resin such as PET (polyethylene terephthalate) and provided with four ring-shaped patterns (a current collecting pattern and a resistor pattern) 35 around the through-hole 33. Further, a terminal portion 39 to which five metal terminal pieces 37 are fixed is provided at an end portion of each pattern 35.

A rectangular through hole 41 and a concave portion 43 are provided on the side of the flexible substrate 30.

Here, FIG. 2 shows the terminal 39 as shown in FIG.
FIG. 3 is an enlarged cross-sectional view taken along line A. As shown in the figure, the terminal portion 39 has a metal terminal strip 37 placed on the end of each pattern 35, and a terminal fixing film 45 made of PET film placed thereon. The film 31 on both sides of the film 37 and the terminal fixing film 45 are ultrasonically welded by an ultrasonic horn so that the metal terminal pieces 37 are strongly sandwiched and fixed.

Returning to FIG. 1, the knob 50 is formed by molding a molding resin into a substantially disk shape, and has a through hole 51 in the center thereof for rotatably inserting the support projection 21 of the mounting plate 20. Is provided.

A slider (not shown) made of metal, which is in sliding contact with each pattern 35 provided on the flexible substrate 30, is attached to the lower surface of the knob 50.

In order to assemble the rotary variable resistor 10, first, the flexible substrate 30 is mounted on the mounting plate 20.
Is placed. At this time, the support projection 21 of the mounting plate 20 penetrates the through hole 33 of the flexible substrate 30 and the stopper 2
3 penetrates the concave portion 43, one of the supports 25 passes through the through hole 41, and the other three supports 25 are located around the flexible substrate 30.

At this time, the vicinity of both ends of the back surface of the terminal portion 39 of the flexible board 30 is in contact with the tip sides 27a, 27a of the small projections 27, 27 of the mounting plate 20.

FIG. 3, FIG. 4 and FIG.
Of the terminal portion 39 using the small projection 27
It is a principal part expanded side sectional view which shows the method of fixing so that it may closely contact on 0.

That is, as shown in FIGS. 3A and 3B, the ultrasonic horn 40 is located on the terminal portion 39 of the flexible substrate 30 and directly above the small projection 27 of the mounting plate 20.
Place. The mounting plate 20 is mounted on a support (not shown).

Next, as shown in FIGS. 4A and 4B, the ultrasonic horn 40 is lowered to come into contact with the upper surface of the terminal portion 39, and the ultrasonic horn 40 is driven so that the terminal portion 39 is ultrasonically driven. When the ultrasonic horn 40 is slightly pressed while being heated, the contact portion of the ultrasonic horn 40 is heated and softened, and the small projection 27 is fixed to the film 31 constituting the terminal portion 39 by the pressing force of the ultrasonic horn 40 applied at the same time. The lower surface of the film 31 comes into close contact with the upper surface of the mounting plate 20. Since the small projections 27 are pierced into the films 31 and 45 while being softened by the ultrasonic heating, there is no impact, and there is no adverse effect on the portion where the pattern 35 and the metal terminal piece 37 are electrically connected.

The tip side 2 of the small projection 27 pierced
7 a is in contact with the lower surface of the ultrasonic horn 40 and is deformed flat by the ultrasonic vibration of the ultrasonic horn 40.

When the tip side 27a of the small projection 27 is deformed by using the ultrasonic horn 40 as described above, it is desirable that the lower surface of the ultrasonic horn 40 is made of a super hard material.

Then, as shown in FIGS. 5A and 5B,
If the ultrasonic horn 40 is removed, the mounting plate 20 and the terminal 3
Fixation between 9 is completed.

As described above, the small protrusions 27 are formed on the synthetic resin film 3 constituting the terminal portions 39 of the flexible substrate 30.
1, 45, and the tip side 27a is crushed, so that the fixing plate 20 and the terminal portion 39 can be fixed.

FIG. 6 is an enlarged side sectional view of a main part showing another embodiment of the present invention. Also in this embodiment, the small projection 27 is pierced into the synthetic resin films 31 and 45 by the same ultrasonic horn 40 as shown in FIG. 3, but in this embodiment, the tip side 27a of the small projection 27 is crushed. Absent.

Even with this configuration, the small projections 27 pierce the synthetic resin films 31 and 45 that have been heated and softened, so that the synthetic resin films 31 and 45 can be cooled.
Due to the contraction force of 45, the small projections 27 are sandwiched between the synthetic resin films 31 and 45 from both sides thereof, so that the small projections 27 can be fixed.

In the case where the terminal portion 39 does not come off from the mounting plate 20 when the rotary variable resistor 10 is solder-reflowed onto another substrate or the like, if the fixing force of a sufficient degree is sufficient, the fixing of the above structure is sufficient. .

In each of the above embodiments, the present invention has been described with respect to an example in which the terminal portion of the flexible substrate for a rotary electronic component is fixed to the mounting plate. However, the present invention is not limited to this, and other various films may be used. It can be used as a fixing structure for mounting to a mounting plate made of a metal plate.

[0041]

As described above in detail, according to the present invention, fixing between the mounting plate and the film (the terminal portion of the mounting plate and the flexible substrate) can be easily performed without increasing the thickness of the fixing portion. Can do it. According to the present invention,
There is no shock because the small projections are pierced into the film while being softened by ultrasonic heating, so even if this fixing structure is provided near the terminal part of the flexible substrate, the electrical connection between the pattern of the flexible substrate and the metal terminal piece Has no adverse effect on

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a rotary variable resistor 10 according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view taken along line AA of a terminal section 39 shown in FIG.

FIG. 3 is an enlarged side sectional view of a main part showing a method of fixing a terminal portion 39 to a mounting plate 20.

FIG. 4 is an enlarged side sectional view of a main part showing a method of fixing the terminal portion 39 to the mounting plate 20.

FIG. 5 is an enlarged side sectional view of a main part showing a method of fixing the terminal portion 39 to the mounting plate 20.

FIG. 6 is an enlarged side sectional view of a main part showing another embodiment of the present invention.

FIG. 7 is an exploded perspective view showing a conventional rotary variable resistor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rotary variable resistor 20 Mounting plate 27, 27 Small protrusion 30 Flexible board 31 Film 35 Pattern 37 Metal terminal strip 39 Terminal part 45 Terminal fixing film 50 Knob

Claims (2)

(57) [Claims] 1. A film comprising a thermoplastic synthetic resin,
A mounting portion made of a metal plate, a small projection protruding in the film direction at a predetermined position of the mounting plate, and a film portion with which the small projection abuts when the film is placed on the mounting plate. A portion where the small projection of the film contacts
Due to the ultrasonic vibration of the ultrasonic horn
The small projections are pressed by heating and softening.
Push the ultrasonic horn into the film
Abuts on the tip of the small projection that protrudes into the film.
A fixing structure of a film and a mounting plate, characterized in that the both ends are fixed by crushing the ends . 2. A flexible board which forms a desired pattern on an upper surface of a film made of a thermoplastic synthetic resin and has a metal terminal piece fixed to an end of the pattern to form a terminal, and a mounting plate made of a metal plate. Wherein the flexible substrate is mounted on a mounting plate, and a terminal portion of the flexible substrate is fixed to the mounting plate. A small projection protruding in the direction of the flexible substrate is provided in a portion where the portion is placed, and the film portion of the terminal portion that contacts the small projection when the flexible substrate is placed on the mounting plate is reduced in size.
Ultrasonic horn in contact with the opposite side of the part where the projection contacts
Pressed while softened by heating by ultrasonic vibration of
By pushing the small projection into the film of the terminal part
In both cases, the ultrasonic horn protrudes into the film
By contacting the tip and crushing the tip of the small projection,
The terminal part fixing structure of the flexible substrate, characterized by fixing the terminal.