JPS6229931Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration detector that detects vibrations generated by unbalance during rotation of a rotating body, for example, when measuring the unbalance of the rotating body.

Such a vibration detector is necessary for measuring the amount of unbalance of a rotating body by detecting vibration. Since this type of detection requires the detection of high-frequency vibrations, a detector using a bimorph element, which is used in audio equipment, has been devised.

That is, as shown in FIG. 1, a sealed detection box 1 is filled with silicone oil 7.
A detection plate s whose base is attached to the inner wall of the detection box 1 is provided therein, and a weight body 6 is further attached to the tip of the detection plate s. This detection box 1 is connected to a vibrating body (not shown) via a mounting screw 5.
The sensor is installed in the center and is designed to detect vibrations.

By the way, this detection plate s is a bimorph element, that is, the electrode plate 2 is sandwiched in the center, and the piezoelectric element plate 3,
4 are joined together, and the piezoelectric element plates 3 and 4 have a thickness sufficient to form a fixed detection plate. Such a vibration detector has a good vibration detector, but the present invention is such a detector,
The aim is to provide a vibration detector with even higher accuracy.

The vibration detector of the present invention will be explained below with reference to FIGS. 2 to 5. FIG. 2 is a diagram showing the basic structure of the present invention, and the same reference numerals as in FIG. 1 indicate the same parts.

The feature of this invention is the vibration detection plate. That is,
The detection plate is constructed by placing an elastic plate 10 having a certain thickness in the center and serving as an electrode, and joining thin piezoelectric element plates 8 and 9 to both sides of the elastic plate 10. This elastic plate 1
The thickness of the joined body of 0 and the piezoelectric element plates 8 and 9 is large enough to have vibration rigidity to enable vibration detection. The elastic plate 10 is made of a certain thickness, and the piezoelectric element plates 8 and 9 are made of thin plates. Since the elastic plate 10 also serves as an electrode, it is conductive and elastic.

3 to 5 show an embodiment of a vibration detector, in which a detection box 11 has a cylindrical shape, and vibration detection plates are installed inside thereof in two stages, upper and lower. A convex portion 11' is formed at the bottom of the detection box 11, and above the convex portion 11', support frames 13 and 14 constituting the inner wall are connected to the connecting bolt 1.
It is fixedly mounted via 5. and convex part 1
1' and the support frame 13, as shown in FIG. As shown in FIG. 2, a vibration detection plate consisting of an elastic plate 17 and piezoelectric element plates 20 and 21 is installed. 24 to 27 are weight bodies fixed to the ends of these vibration detection plates, and 28 and 29 are mounting screws thereof. The detection box 11 is sealed and filled with silicone oil 7.
is filled. Lead wires 22 and 23 are connected to the vibration detection plate, respectively, and are collected in the connector 12 to output an electric signal corresponding to the vibration.

As described above, according to the present invention, since the vibration detection plate is constructed by sandwiching a relatively thick elastic plate between relatively thin piezoelectric element plates, sufficient mechanical strength can be achieved, and the vibration detection plate can be Since it is held almost in the center and arranged in a cross shape, the balance of the detector as a whole is improved, and since two vibration detection plates are used, the measurement sensitivity is increased and a detector with good accuracy can be obtained. Can be done.

[Brief explanation of the drawing]

Fig. 1 shows a conventional detector, Fig. 2 shows the principle of the present invention, Figs. 3 to 5 show specific examples, and Fig. 4 shows a plan view of Fig. Figure 5 is the third
FIG. 1, 11... Detection box, 10, 16, 17... Elastic plate, 8, 9, 18, 19, 20, 21... Piezoelectric element plate, 6, 24, 25, 26, 27... Weight body, 7 ... Silicone oil, 13, 14 ... Support frame, 15 ... Connection bolt, 22, 23 ... Lead wire.

Claims (1)

[Scope of utility model claims] It consists of a detection box forming a sealed chamber, a pair of vibration detection plates disposed inside the detection box, and a damper liquid filled in the sealed chamber. In a vibration detector that outputs an electrical signal corresponding to vibration from a detection plate, each of the pair of vibration detection plates has a relatively thick elastic plate that also serves as an electrode, and a relatively thin piezoelectric plate bonded to both sides of the elastic plate. and an element plate, with the pair of vibration detection plates placed at an appropriate distance vertically,
A vibration detector characterized in that each vibration detection plate is held at approximately the center in the longitudinal direction so as to extend in directions substantially orthogonal to each other, and weight bodies are attached to both ends of each vibration detection plate.