JP2524887Y2 - Piezoelectric vibration gyro - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric vibrating gyroscope, and more particularly to a gyroscope mounted on a ship or a car for controlling its attitude and route, particularly utilizing the ultrasonic vibration of a piezoelectric vibrator. The present invention relates to an improvement in a supporting structure of a piezoelectric vibrator in a piezoelectric vibrating gyroscope.

[0002]

2. Description of the Related Art A piezoelectric vibrating gyroscope is a type of gyroscope utilizing a mechanical phenomenon in which when a rotational angular velocity is applied to a vibrating object, a Coriolis force is generated in a direction orthogonal to the direction of vibration. When the piezoelectric vibration is rotated, a force acts in a direction orthogonal to the vibration by the action of the Coriolis force, and the other vibration is excited. The magnitude of this vibration is proportional to the magnitude of the input-side vibration and the rotational angular velocity. Therefore, when the input voltage is kept constant, the magnitude of the rotational angular velocity can be obtained from the magnitude of the output voltage.

FIG. 4 shows an example of the structure of such a conventional piezoelectric vibrating gyroscope. Electrodes are formed on both sides of the adjacent surface of the metal prism 7 having a square cross section, and the piezoelectric ceramic thin plates 8 and 9 polarized in the thickness direction are joined. The metal prism 7 can bend and vibrate in two directions orthogonal to each other at substantially the same resonance frequency.
When a voltage having a frequency equal to the resonance frequency is applied to the piezoelectric ceramic thin plate 8, the surface to which the piezoelectric ceramic thin plate 8 is bonded vibrates in a direction in which the surface becomes uneven. In this state, no voltage is generated on the piezoelectric ceramic thin plate 9 of the metal prism 7, but when the metal prism 7 is rotated around the length direction,
By the action of the Coriolis force, the metal prism 7 bends and vibrates in a direction in which the surface on which the piezoelectric ceramics 9 are bonded becomes uneven, and a voltage proportional to the rotational angular velocity is generated in the piezoelectric ceramics 9.

By the way, perpendicularly to the center of the metal surface opposite to a position approximately 22.4% of the entire length from one end face in the length direction of the metal prism 7 which is a piezoelectric vibrator having the above-described structure and properties. Support wires 10, 1 each made of a thin metal wire
0 'is welded. Further, supporting wires 11 and 11 ′ made of thin metal wires are welded vertically to the center of the metal surface opposite to a position about 22.4% of the entire length from the other end face. These metal wires 10, 10, 11 and 1
The portion where 1 'is welded is a node of the vibration with respect to the bending resonance vibration mode of the prism 7, and a thin metal wire is used for the support so that the influence of each of the bending vibrations orthogonal to each other is minimized. -ing

[0005]

However, according to the conventional supporting method as shown in FIG. 4, according to the conventional supporting method, as shown in FIG. 5, the supporting wires 10, 10 'are almost ideal for bending vibration in the direction of the arrow. This means that the vibration contacts are supported. However, at this time, bending distortion occurs in the supporting wires 11 and 11 ', which has a bad influence on bending vibration in the direction of the arrow. On the other hand, the supporting lines 10, 10 'similarly affect the bending vibration in the direction orthogonal to the arrow in the figure. In order to minimize the influence on the bending vibration, the diameter of the support wire may be made as small as possible. However, if the support wire is too thin, the vibration resistance and shock resistance of the piezoelectric vibrator itself may be deteriorated.

Further, in this piezoelectric vibrating gyroscope, the vibrator is formed of a single piezoelectric ceramic, and the strip-shaped electrodes formed on the outer peripheral surface thereof are formed by screen printing or vapor deposition. Accordingly, supporting a support wire made of a very thin metal wire by welding or soldering is even more dangerous from the viewpoint of vibration resistance and durability shock characteristics.

The object of the present invention has been proposed in view of the above-mentioned problems of the prior art, and eliminates the drawbacks of the conventional method of supporting a piezoelectric vibrating gyroscope, thereby reducing the influence on bending vibration in a direction perpendicular to the direction. An object of the present invention is to provide a piezoelectric gyro that is symmetrical in the direction of vibration with respect to each vibration direction and has little effect on the characteristics of the piezoelectric vibratory gyro.

Another object of the present invention is to provide a piezoelectric vibrating gyroscope that can be stably supported by using a piezoelectric vibrator in which a band-shaped electrode is formed on the outer periphery of a columnar vibrator made of piezoelectric ceramics alone.

[0009]

For this reason, the piezoelectric vibrating gyroscope of the present invention forms a strip electrode parallel to the length direction on the outer peripheral surface of the columnar piezoelectric ceramics, and performs a polarization process using the strip electrode. In a piezoelectric vibrating gyroscope that drives and detects using the bending vibration mode of the columnar piezoelectric ceramics using the piezoelectric effect, minute projections are integrally formed at two positions corresponding to vibration nodes at one-wavelength resonance of the bending vibration mode. After inserting the columnar piezoelectric ceramics into a cylindrical support made of a soft elastic material such as silicon rubber, the microprojections and the piezoelectric ceramics are supported at the positions of the nodes of the bending vibration using a particularly soft silicone adhesive. Fixing is a basic configuration.

[0010]

FIG. 1 is a perspective view showing a structural example of a columnar piezoelectric ceramic used in a piezoelectric vibrating gyroscope according to the present invention.
A plurality of strip-shaped electrodes 21 are formed at positions equally dividing the circumference on the outer peripheral surface of the piezoelectric ceramic cylinder 20 in parallel with the length direction. These strip electrodes 21 constitute input / output terminals, and are formed directly by curved screen printing, or easily formed by removing unnecessary portions of the electrodes formed on the entire surface by plating or the like by photoetching. It is obtained.

The piezoelectric ceramic cylinder 20 is subjected to a polarization treatment using the strip electrodes, and then an AC voltage substantially equal to the resonance frequency of the bending vibration of the piezoelectric ceramic cylinder 20 is applied to a part of the strip electrodes. When the piezoelectric ceramic cylinder 20 is rotated around the longitudinal axis in a state where the bending vibration is caused, Coriolis force is generated in a direction orthogonal to the vibration direction, and is proportional to the rotational angular velocity applied to a part of the strip electrode. The generated voltage is generated.

FIG. 2 shows a support 30 used in the piezoelectric gyro of the present invention. The support 30 has a cylindrical structure made of a soft elastic body such as silicon in which minute projections 22 are integrally formed at two locations corresponding to vibration nodes in one-wavelength resonance in the bending vibration mode.

FIG. 3 shows an assembled state of the piezoelectric vibrating gyroscope according to the present invention. The support 30 shown in FIG. 2 accommodates the piezoelectric ceramic 20 of FIG.
Are further mounted on a cylindrical outer case 31 made of metal or plastic. That is, the microprojections 22 and the piezoelectric ceramics 20 are supported and fixed at the nodes of the bending vibration thereof using a particularly soft silicone adhesive or the like, and are housed and mounted in the outer case 31.

In general, in order to support a resonating vibrator as much as possible without affecting the vibration, it is necessary to support points (or lines) of vibration nodes with a soft material.
However, in order to stably support external vibrations and shocks, it is necessary to fix the vibrator at the support portion so as not to shift. The support 30 of the present invention is made of soft silicone rubber as described above, and is also fixed to the piezoelectric ceramics 20 with a soft silicone adhesive, so that the vibrator is not affected by external vibration or shock. It can be stably supported so as not to shift.

Further, in the piezoelectric vibrating gyroscope according to the present invention, since the shape of the minute projections 22 of the support 30 is ring-shaped, the piezoelectric vibrating gyroscope is symmetrically supported with respect to both the excitation vibration direction and the vibration due to Coriolis force. Therefore, the influence of the support on the characteristics as the piezoelectric vibrating gyroscope is reduced.

In the above description, the case where the shape of the columnar piezoelectric ceramic is cylindrical is described. However, the shape of the columnar piezoelectric ceramic may be a prism having a square shaft cross section or another prism having a regular polygonal shaft cross section. It can be configured similarly.

[0017]

According to the present invention, there is little deterioration in vibration characteristics due to support, and there is little influence on bending vibration in two directions perpendicular to each other, and the influence is symmetric with respect to each vibration direction. Further, since the microprojections of the support of the present invention are integrally formed corresponding to the nodes of vibration at one-wavelength resonance, by aligning one microprojection with the position of one node, the other position becomes A piezoelectric gyro can be obtained in which the influence of the characteristics of the piezoelectric vibrating gyroscope which automatically becomes the position of another node is small and the reliability is greatly improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the structure of a piezoelectric ceramic cylinder used in the piezoelectric vibrating gyroscope of the present invention.

FIG. 2 is an axial sectional view showing a support used in the present invention.

FIG. 3 is a perspective view showing the structure of the piezoelectric vibrating gyroscope according to the present invention.

FIG. 4 is a schematic structural view of an example of a conventional piezoelectric vibrating gyroscope.

FIG. 5 is an explanatory view showing a conventional method of supporting a piezoelectric vibrating gyroscope.

[Explanation of symbols]

 1, 1 ', 2 and 2' Metal vibrating piece resonator 3, 4, 5, 6 Piezoelectric ceramic thin plate 7 Metal prism 8, 9 Piezoelectric ceramic thin plate 10, 10 ', 11, 11' Metal support wire 20 Piezoelectric ceramic cylinder 21 Strip electrode 22 minute projection 30 support 31 outer case

Claims (1)

(57) [Scope of request for utility model registration] 1. A strip-shaped electrode parallel to the length direction is formed on an outer peripheral surface of a columnar piezoelectric ceramic, a polarization process is performed using the strip-shaped electrode, and a bending vibration mode by a piezoelectric effect of the columnar piezoelectric ceramic is used. In a piezoelectric vibrating gyroscope for driving and detecting, a cylindrical support made of a soft elastic body such as silicon rubber having minute projections integrally formed at two positions corresponding to vibration nodes at one-wavelength resonance in the bending vibration mode. A piezoelectric vibrating gyroscope, wherein the columnar piezoelectric ceramics are inserted into the piezoelectric vibrating member, and the minute projections and the piezoelectric ceramics are supported and fixed at predetermined bending vibration nodes by a predetermined adhesive.