JPS6067815A - Angular velocity sensor - Google Patents

Abstract

PURPOSE:To remove unsteadiness of connection of driving and detecting members, by integrating said members into a single body and attaching piezo-electric crystals on each of them. CONSTITUTION:Upon metallic plates 4, 4' integrated in such a way that top and bottom are set through an angle of 90 deg. against each other, piezo-electric crystals for driving 5, 5', those for detection 6, 6' are jointed. To the metallic plates 4, 4', a metallic terminal 7 is fastened by welding and soldering, etc., and outgoing lead wires 8, 8' are connected with the driving piezo-electric crystals 5, 5'. The driving piezo-electric crystals 5, 5' elongate and contract by an AC voltage applied through the terminal 8' and excite the metallic plates 4, 4' to generate symmetrical vibration with a phase difference of 180 deg.. The vibration of the metallic plates 4, 4' is converted to an electric signal through a detecting piezo- electric crystals 6, 6' and then to angular velocity through a detecting circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a piezoelectric vibration type angular velocity sensor.

[Prior art]

Conventionally, as this type of device, there is a piezoelectric vibration type angular velocity sensor shown in FIG.

To explain the structure of this device, there is a driving piezoelectric bimorph 1.1' (driving part) made of two piezoelectric plates pasted together, and a sensing piezoelectric made of two piezoelectric sheets stuck together like this driving piezoelectric bimorph 1.1'. Bimorph 2.2' (detection part)
are glued together with adhesive 3.3' so that they are perpendicular to each other.

Then, an AC voltage is applied to the driving piezoelectric bimorphs 1 and 1', causing the driving piezoelectric bimorphs 1 and 1' to vibrate with a phase shift of 180° in the direction of the arrow in the figure. The angular velocity is obtained by detecting the bending state of the piezoelectric bimorph 2.2' in the vertical direction.

That is, when an angular velocity occurs around the measurement axis, the detection piezoelectric bimorph 2.2' is bent by the Coriolis force, so the angular velocity is obtained by detecting the bent state.

However, this method uses piezoelectric bimorph for driving.
1, 1' Piezoelectric 8 imorph 2.2' for color detection is bonded with adhesive 3.3', and the joint has an unstable shape, so there is a problem with long-term reliability. .

Further, there are also problems such as the characteristics being deteriorated due to differences in vibration modes due to non-uniform application of the adhesive 3, 3'.

[Purpose of the invention]

The present invention has been developed in view of the above problems, and its purpose is to improve long-term reliability and detection accuracy by connecting the driving part and the sensing part without using an adhesive. The purpose is to provide an angular velocity sensor (Jj).

[Purpose of the invention]

In order to achieve the above object, the present invention includes a substrate formed integrally with a plate-shaped drive part and a plate-shaped detection part perpendicular to the drive part, and bonded to at least one of the front and back sides of the drive part. a piezoelectric body for driving, a piezoelectric body for sensing bonded to at least one of the front and back sides of the sensing unit, two sets of vibrating units are arranged facing each other so that the driving units are parallel to each other, and each drive The driving piezoelectric bodies are expanded and contracted to vibrate each of the driving parts in the vertical direction, and an electric signal is applied to each of the driving piezoelectric bodies so that the vibrations in the vertical direction are out of phase by 18 degrees. an expansion/contraction state of the detection piezoelectric body when the detection section is vibrating due to vibrations of the electric signal supply means and the drive section, and the detection section is bent in the vertical direction due to the influence of angular velocity; The present invention is characterized by comprising a detection means for extracting the signal as an electric signal.

〔Effect of the invention〕

As described above, in the present invention, the drive section and the detection section are integrally formed, and the piezoelectric material is bonded to each, so that the instability of the bond between the drive section and the detection section is eliminated. This has the excellent effect of improving long-term reliability as well as improving detection accuracy.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 2 is a perspective view showing one embodiment. In Fig. 2, 4.4' is a metal plate (0°5 ml thick Fe-C
0-N1 alloy), and on top of that are a driving piezoelectric body 5.5' and a sensing piezoelectric body 6.6' (each with a thickness of 0-N1).
．． (using 2U PZT ceramics) is bonded. 7 is a metal terminal, which is fixed to the metal plate 4.4' by welding, soldering, etc. 8.8' are terminals for drawing out lead wires from the detection piezoelectric body 6.6' and the driving piezoelectric body 5, 5', respectively.

Next, the operation will be explained using the schematic configuration shown in FIG. In FIG. 3, reference numeral 9 denotes an AC driving power source, which applies an AC voltage to the driving piezoelectric body 5.5' via a terminal 8'. The driving piezoelectric bodies 5, 5' expand and contract in response to the alternating current voltage, causing the metal plate 4.degree. 4' to vibrate as shown by the arrows in FIG. Here, since the polarization direction of the driving piezoelectric bodies 5, 5' is in the direction of the arrow in the figure, the vibration of the metal plate 4,4' is 180° out of phase, that is, a symmetrical vibration. During the vibration, when the detection part of the metal Fj4.4' bends as shown by the dotted arrow in FIG. is expanded or contracted, and the detection circuit 10 detects an electrical signal corresponding to the expansion or contraction. Since the electrical signal corresponds to the angular velocity, the angular velocity is detected using the electrical signal. In addition, the drive piezoelectric body 5.5
The adhesive surface of the detection piezoelectric body 6.6' with the metal plate 4.4' is grounded through the metal plate 4.4' and the metal terminal 7.

In the above embodiment, the drive piezoelectric body 5, 5' and the detection piezoelectric body 6.6' are bonded only to one side of the metal plate 4.4', but as shown in FIG. , drive piezoelectric body 5
．． 5', detection piezoelectric bodies 6.6' may be provided on both sides of the metal plate 4.4'. (In the figure, the detection piezoelectric body 6,
Although only one side of 6' is shown, metal plates 4, 4
'The same thing is glued on the other side. ) Alternatively, as shown in FIG. 5, the metal plate 4, 4' may be manufactured by a simple bending process of just bending the metal plates 4, 4' at right angles.

Further, although the metal plate 4 is used as the substrate, it may be made of ceramic. In this case, the driving piezoelectric body 5
．． 5', it is necessary to separately provide an electric wire for grounding the detection piezoelectric body 6 and 6'.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a conventional vibration type angular velocity sensor, FIGS. 2 and 3 are perspective views and schematic configuration diagrams showing one embodiment of the present invention, and FIG. 4 is another embodiment of the present invention. A schematic configuration diagram showing
FIG. 5 is a perspective view showing another embodiment of the present invention. 4.4'...metal plate, 5.5'... piezoelectric body for drive,
6.6'...Piezoelectric body for detection, 9...Drive power source, 10
...Detection circuit. Representative Patent Attorney Takashi Okabe

Claims (1)

[Scope of Claims] A substrate formed integrally with a plate-shaped drive part and a plate-shaped detection part perpendicular to the drive part, and a drive piezoelectric material bonded to at least one of the front and back sides of the drive part. and a detection piezoelectric body bonded to at least one of the front and back surfaces of the detection unit, two sets of vibrating units are arranged opposite to each other so that the drive units are parallel to each other, and each drive piezoelectric body is an electric signal supply means for applying an electric signal to each of the drive piezoelectric bodies so that the drive parts are vibrated in the vertical direction by expanding and contracting, and the vertical vibrations are out of phase by 180°; and when the detection section is vibrating due to the vibration of the driving section, and when the detection section is bent in the vertical direction due to the influence of angular velocity, the expansion and contraction state of the detection piezoelectric body is expressed as an electric signal. An angular velocity sensor equipped with a detection means for taking out.