JP3309748B2 - Acceleration sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration sensor used for general vibration detection and acceleration measurement.

[0002]

2. Description of the Related Art Conventionally, this kind of acceleration sensor has the following configuration. In other words, electrodes are applied to the entire surface of the front and back surfaces of the chip-shaped piezoelectric ceramic, fixed to the two lead wires of the can package, the fixed portion is reinforced with epoxy resin, and a cantilever-shaped flexural oscillator is formed. Was formed. In the acceleration sensor configured as described above, when external vibration is applied in the vertical direction, the cantilever portion of the vibrator senses the vibration,
A flexure corresponding to the magnitude of the external vibration is generated, an electric charge corresponding to the magnitude of the flexure is generated by a piezoelectric effect, and is taken out as an output voltage through a lead wire.

[0003]

In such a conventional configuration, the output voltage generated by external vibration is 9 G / G.
mV is about _op, the lower becomes the acceleration decreases the S / N ratio following 0.1G acceleration, there is a problem that measurement can not be.

[0004] The present invention solves such a problem, and increases S / N at low acceleration by increasing voltage sensitivity.
It is intended to improve the ratio.

[0005]

In order to solve this problem, the present invention provides a piezoelectric element, which is bonded between upper and lower ends of two piezoelectric ceramics with a stator interposed therebetween, to a lead wire of a can package. It is soldered and the soldered portion is covered with epoxy resin.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, when external vibration is applied to two fixed piezoelectric ceramics, the cantilever senses the vibration, and charges are generated in each of them. Is obtained.

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. In FIGS. 1 and 2, reference numeral 1 denotes a chip-shaped piezoelectric ceramic, two of which are bonded and fixed between upper and lower ends by a stator 2 to form a vibrator. Each electrode part of this vibrator is fixed to the lead wire 4 of the plug 3 of the can package by solder, and the fixed part is covered with an epoxy resin 5 to reinforce the case. I have.

When an external vibration is applied to the vibrator of the acceleration sensor constructed as described above in a vertical direction, the upper part of the vibrator senses the vibration and generates a flexure corresponding to the magnitude of the external vibration to generate a piezoelectric effect. As a result, a charge corresponding to the magnitude is generated, and is taken out as an output voltage through the lead wire 4.

[0009]

As described above, according to the present invention, by forming the acceleration sensor by increasing the number of piezoelectric vibrators by using the stator, the voltage sensitivity can be reduced by N compared to a single piezoelectric ceramic.
Can be doubled.

[Brief description of the drawings]

FIG. 1 is a front view of an acceleration sensor according to an embodiment of the present invention.

FIG. 2 is a side view of the acceleration sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric ceramic 2 Stator 4 Lead wire 5 Epoxy resin

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01P 15/09 G01H 11/08 H01L 41/08

Claims (1)

(57) [Claims] 1. An acceleration in which a piezoelectric element bonded between upper and lower ends of two piezoelectric ceramics via a stator is soldered to a lead wire of a can package, and the soldered portion is covered with epoxy resin. Sensors.