JPS6325520A - Vibration detector - Google Patents

Abstract

PURPOSE:To achieve a higher vibration detecting sensitivity, by covering a plate spring for transmitting vibration with an armor case to be free from the suppression of vibration due to an external factor. CONSTITUTION:A piezo-electric ceramic vibrator 9 is stuck on a bottom surface of a first cylindrical metal case 10 to form a bimorph vibrator integral therewith. A hemispherical mobile element 11 is so arranged at the center of an external side of the vibrator so as to move freely. A second cylindrical case 12 having an elastic member 13 on the internal side thereof is fixed on the external side of the case 10 through an elastic adhesive 14. Then, a metal plate spring 15 has bend sections 16 at several points aimed at a smaller size of the apparatus while a groove 7 is provided at the center thereof to enhance the elasticity. One end of the spring 15 is fixed at the open end of the case 10 while the other end thereof done on the armor case 18 and the case 10 and the spring 15 are located at a fixed space from the case 18. Thus, the bimorph vibrator and the mobile element 11 as vibration detecting section are housed in the case 18 to eliminate the attenuation of vibration due to a fouling thereby making the moving part free from the suppression of vibration even when hitting an approaching object.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vibration detection device used in the industrial field, particularly in automobiles.

BACKGROUND OF THE INVENTION Conventionally, this type of vibration detection device has had a configuration as shown in FIG. In Fig. 3, 1 is a piezoelectric ceramic vibrator;
It is bonded to the bottom surface of a metal cylindrical case 2 to constitute a bimorph resonator. A movable element 3 is disposed on the upper surface of this bimorph vibrator, and the movable element 3 and the bimorph vibrator are housed in a frame 5, and at the same time, a detection circuit section 4 is built in and hermetically sealed. The frame body 5 was fixed to one end of an elastic plate spring, and a fixing member was provided at the other end of the plate spring 6. Further, 8 is an external lead wire.

Problems to be Solved by the Invention In such a conventional configuration, since the plate spring portion is exposed, if dirt adheres or comes into contact with a nearby object,
In addition to being unable to detect vibrations, since the detection circuit is housed integrally with the bimorph vibrator, there is a problem in that vibration detection sensitivity is reduced.

The present invention is intended to solve such problems, and aims to provide a structure that is not subject to vibration suppression due to external factors, and to improve vibration detection sensitivity.

Means for Solving the Problem In order to solve this problem, the present invention provides a first cylindrical case in which a piezoelectric ceramic vibrator is bonded to a bottomed surface, and an opening end of the first cylindrical case. A metal leaf spring is fixed at one end and the other end is fixed to the exterior case, and has a plurality of bent parts for adjusting the vibration frequency, and a metal leaf spring that is fixed to the outside of the bottomed surface of the first cylindrical case. a second cylindrical case that is fixed to the first cylindrical case via an elastic adhesive, houses the movable member therein, and has an inner surface made of an elastic material; A case, a detection circuit section having a lead wire for detecting a signal from the piezoelectric ceramic vibrator and outputting it to the outside, the first cylindrical case, a metal leaf spring, and a second cylindrical case.

The detection circuit section is comprised of the above-mentioned exterior case that houses and seals the detection circuit section.

Function: With this configuration, the leaf spring that transmits vibrations is covered with an outer case, so there is no vibration damping due to dirt adhesion, and the vibration is not suppressed even if it hits a nearby object. This makes it easier for imaging to occur between the oscillator surface and the bimorph resonator surface.

Embodiment FIG. 1 is a sectional view of a vibration detection device according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the same. In the figure, reference numeral 9 denotes a piezoelectric ceramic vibrator, which is bonded to the bottomed surface of a first cylindrical case 10 made of metal, and is integrated with the nodal case 1o to constitute a bimorph vibrator. A second cylindrical case 12 in which a hemispherical movable element 11 is disposed in the center of the outer surface of the bimorph vibrator section of the first cylindrical case 10 so as to be freely movable, and an elastic member 13 is formed on the inner surface. , the movable element 1
1 is stored therein, and the first node-shaped case 1o
It is fixed to the outer surface of the body with an elastic adhesive 14. 15
is a metal plate spring, which has multiple bent portions 16 for the purpose of miniaturizing the device, and is formed with a groove portion 1a in the center for the purpose of improving elastic force. The open end of the first cylindrical case 10 is fixed to one end of the plate spring 15, and the other end of the plate spring 15 is fixed to the outer case 18. The configuration is such that they are positioned at more constant intervals. 19 is a detection circuit section.

20 is a lead wire for transmitting the electric output of the bimorph vibrator to the detection circuit section 19; 21 is an external lead wire for outputting the output signal of the bimorph vibrator detected by the detection circuit section 1 to the outside; It is fixed to the exterior case 18. Further, 22 is a sealing plate, and the outer case 18
The leaf spring 15 and the first knot-shaped case 10. The second cylindrical case 12 and the detection circuit section 19 are housed therein and sealed.

Effects of the Invention As described above, according to the present invention, since the bimorph oscillator and movable element, which are vibration detection units, are housed in the exterior case, there is no vibration damping due to dirt, and even if the vibration hits a nearby object, the vibration is not damped. It is possible to have a configuration in which this is not suppressed. In addition, the detection circuit section is separated from the vibration detection section, and the vibration detection section is composed of the leaf spring, the first cylindrical case, the second cylindrical case, and the movable element, and is movable using the vibration of the leaf spring. The vibration detection sensitivity is improved by using a configuration that detects vibrations instead of the movement of the child, and the distance between the second cylindrical case and the first cylindrical case is adjusted and the shape of the movable child is selected. This provides the effect of being able to set a specific detection frequency. Furthermore, in order to protect against external impact with the exterior case, a leaf spring and a first casing are used. The second cylindrical case can be made smaller, and the vibration detection device as a whole can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a vibration detection device according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the same, and FIG. 3 is a sectional view showing a conventional vibration detection device. 9...piezoelectric ceramic vibrator, 1o...first cylindrical case, 11...mover, 12...second cylindrical case, 13...elastic member, 14... Elastic adhesive, 15... Leaf spring, 16... Bent portion, 17... Groove, 18... Exterior case, 19... ...Detection circuit section, 20...Lead wire, 21...External lead wire, 22...Sealing plate. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
figure

Claims (1)

[Claims] a first cylindrical case having a piezoelectric ceramic vibrator bonded to a bottom surface; an opening end of the first cylindrical case fixed to one end and the other end fixed to an exterior case; A metal plate spring having multiple bending parts,
a movable element disposed to be freely movable on the outside of the bottomed surface of the first cylindrical case; and a movable element fixed to the first cylindrical case via an elastic adhesive and housing the movable element inside. and a second cylindrical case whose inner surface is made of an elastic material, a detection circuit section having a lead wire that detects a signal from the piezoelectric ceramic vibrator and outputs it to the outside, and the first cylindrical case. A vibration detection device comprising the above-mentioned outer case that houses and seals a metal plate spring, a second cylindrical case, and a detection circuit section.