JPH0128592Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to the structure of a piezoelectric switch that uses an electromotive force generated by applying strain to a piezoelectric plate as a switching signal.
This relates to an improvement of No. 117874 (Utility Model Publication No. 59-20744). In this piezoelectric switch, a dome-shaped spring is reversed by pushing down a plunger, and the piezoelectric plate is distorted by the impact of the reversed dome-shaped spring. However, in a configuration in which a dome-shaped spring is placed directly on a piezoelectric plate, etc., it is difficult to obtain sufficient impact force unless the height and curvature of the dome are carefully selected, making it difficult to design and process the dome-shaped spring. , there was a problem that the operation tended to become unstable.

The present invention was devised to solve these problems, and an object of the present invention is to provide a piezoelectric switch whose dome-shaped spring is easy to manufacture, whose operation is stable, and whose durability can be improved. For this purpose, the present invention is characterized in that a spacer in the form of a ring with a portion cut out is provided below the dome-shaped spring. Embodiments of the present invention will be described below based on the accompanying drawings.

In FIGS. 1 to 3, reference numeral 1 denotes a housing whose upper and lower surfaces are open and terminals 2 are implanted at the four corners. The housing 1 includes a partition plate 1b having a through hole 1a,
It is equipped with a vertical groove 1c that passes through the partition plate 1b provided on the inner side, and has hook-shaped projections 1 on the two sides.
d is provided. 3 is a substantially rectangular flexible printed circuit board having printed wiring 3a on its lower surface, and after terminals 2 are inserted into through holes 3b at the four corners, the terminals 2 are attached and fixed to the four terminals 2 by soldering. In the center of the printed circuit board 3, there is a printed wiring 3.
It is formed by punching out the circumference of a projecting piece 3c having a free end covered by a, and a chip-shaped resistor 4 and a capacitor 5 for output waveform shaping are mounted on the bottom surface of the printed circuit board 3. It is soldered.
6 is polarized in the thickness direction and has electrodes on both sides (not shown)
The piezoelectric plate is a disc-shaped piezoelectric plate which is placed without being fixed on the partition plate 1b, and its upper surface is adhered to a conductive plate 7 made of brass or the like. Conductive plate 7
, a disk portion 7a to which a piezoelectric plate 6 is fixed, and a disk portion 7
By inserting the lead part 7b through the groove 1c into the through hole 3d of the printed circuit board 3 and soldering it, it can be printed together with the piezoelectric plate 6. It is fixed to the substrate 3. A flexible protrusion 3c provided on the printed circuit board 3 is bent upward and soldered to the lower electrode of the piezoelectric plate 6. A spacer 8 and a dome-shaped metal spring 9 are sequentially placed on the conductive plate 7, and a plunger 10 is further placed on the spring 9. As shown in FIGS. 4A and 4B, the spacer 8 is formed into a substantially C-shape in which a part of a ring is cut out, and has a tongue piece 8a extending obliquely upward near the center of its outer periphery. . Note that 8b indicates a notch portion of the ring. Then, as shown in FIG. 5, the spacer 8 has a tongue piece 8a.
is positioned in the groove 1c and molded into the housing 1. The plunger 10 has a flange 10a and a hemispherical protrusion 10b at its lower portion, and is movable up and down. A cover 11 provided with a hole 11a for inserting the plunger 10 is fixed to the housing 1 by engaging two locking pieces 10b formed on the side surface with a protrusion 1d.

In the piezoelectric switch configured in this way, when the plunger 10 is pushed down, the spring 9 pressed by the protrusion 10b suddenly reverses and strikes the conductive plate 7, giving distortion to the piezoelectric plate 6. Electromotive force is taken out to the terminal 2 through the protruding piece 3c. Thereafter, when the force pushing down the plunger 10 is released, the plunger 10 returns to its original position due to the restoring force of the spring 9. In particular, in the present invention, a spacer 8 in the form of a partially cut-out ring is interposed between the dome-shaped spring 9 and the conductive plate 7, so that stable operation can be achieved even if the spring 9 is formed into an extremely thin dome shape. A strong hitting force can be obtained. In the spacer 8 described above, the reason why the tongue piece 8a extending diagonally upward is formed is that the tongue piece 8a is arranged in the groove 1c and brought into contact with the edge of the dome-shaped spring 9. This is to prevent misalignment. Therefore, if the spacer 8' is formed into a generally ring-shaped spacer 8' with a small notch 8'b as shown in FIG. There is no need to provide such a tongue piece 8a.

Note that the notches 8 provided in the spacers 8 and 8'
The sizes of a and 8'a have a large effect on the operation of the dome-shaped spring 9, and by adjusting the dimensions of these notches 8a and 8'a, the stroke and impact force of the dome-shaped spring 9 can be adjusted. It is possible to adjust.

The piezoelectric switch according to the present invention is not limited to the push-button configuration as described above, but can also be configured to push down the plunger with a cantilevered operation button whose one end is rotatably supported. Also, plunger 10
Instead, a combination of a first plunger 12 having a protrusion 12a that contacts a dome-shaped spring as shown in FIG. 7 and a second plunger 14 capable of pressing the plunger 12 via a coil spring 13 is used. This makes it possible to reduce bounce and equalize the force that presses the dome-shaped spring.

As described above, in the present invention, since the spacer is attached under the dome-shaped spring, the dome-shaped spring can be easily manufactured and a piezoelectric switch with stable operation can be obtained. In addition, since the spacer has a shape in which a part of the ring is notched, not only can the stroke and impact force of the dome-shaped spring be adjusted by the size of the notch, but the notch also acts as an air hole, allowing the dome-shaped spring to It also has the effect of smoothing the reversal movement.

[Brief explanation of drawings]

Fig. 1 is a front view showing an embodiment of the piezoelectric switch of the present invention, Fig. 2 is an exploded perspective view of the same, Fig. 3 is a front sectional view of the same, Fig. 4 shows a spacer, and A is a plan view. , B is a front view, FIG. 5 is a plan view of the main parts of the switch showing the mounting state of the spacer, FIG. 6 is a plan view showing another embodiment of the spacer, and FIG. 7 is another example of the configuration of the plunger part. FIG. DESCRIPTION OF SYMBOLS 1... Housing, 6... Piezoelectric plate, 7... Conductive plate, 8, 8'... Spacer, 8a... Tongue piece, 8b,
8'b...Notch, 9...Dome-shaped spring.

Claims (1)

[Scope of claim for utility model registration] (1) A housing in which a plurality of terminals are embedded, a plunger movably attached to the housing,
A piezoelectric plate that is polarized in the thickness direction and has electrodes on both sides and is attached to the housing via an elastic member, a conductive plate fixed to the top surface of the piezoelectric plate, and a dome-shaped piezoelectric plate placed on the conductive plate. A piezoelectric switch is equipped with a spring, and when the plunger is pushed down, the dome-shaped spring is reversed and hits the conductive plate.A spacer in the form of a cutout of a ring is interposed between the dome-shaped spring and the conductive plate. A piezoelectric switch characterized by: (2) Utility model registration claim No. 1 in which the spacer has a tongue piece extending obliquely upward on a part of its outer periphery.
Piezoelectric switch described in section.