JP2534958Y2 - 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 position 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 as to minimize the influence on each of the bending vibrations orthogonal to each other. -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-shaped electrode parallel to the length direction on the outer peripheral surface of the columnar piezoelectric ceramic, and uses the strip-shaped electrode to form the columnar piezoelectric ceramic. In a piezoelectric vibrating gyroscope that performs polarization processing and drives and detects using a bending vibration mode by the piezoelectric effect of the columnar piezoelectric ceramic, a band-like ring made of a fiber or a foam material is positioned at a node of a bending vibration of the columnar piezoelectric ceramic. And wear it around
The outer periphery of the band-shaped ring is fastened with a hard holder and supported and fixed in the case.

[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 about the longitudinal axis in a state where the bending vibration is excited, 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. Voltage is generated.

FIG. 2 shows a support 30 used in the piezoelectric gyro of the present invention, which is a band-like ring made of soft fiber such as gauze or felt, or foamed material such as styrene foam or sponge.

FIG. 3 shows an assembled state of the piezoelectric vibrating gyroscope according to the present invention, in which a support 30 as shown in FIG. 2 is mounted so as to orbit around two vibration nodes (nodes) of the piezoelectric ceramic cylinder 20. Have been. The outer periphery of the support 30 is tightened and reinforced by a hard holder 31 and attached to the outer case 32.

In general, in order to support a resonating vibrator as much as possible without affecting the vibration, it is necessary to support nodes (or lines) of the vibration with a soft material. However, in order to stably support vibrations and shocks from the outside, it is necessary to fix the vibrator at the support portion so as not to shift. The support 30 of the present invention is formed of a band-like ring made of a soft fiber or a foam material such as styrofoam or sponge as described above, and its periphery is fastened with a hard holder 31 and attached to the outer case. Since it is fixedly supported, both of the above requirements can be satisfied.
Furthermore, since the soft support 30 is fastened by the hard holder 31, the contact area between the support 30 and the vibrator is apparently large, but actually, the support 30 is porous. , The mechanical impedance is well maintained.

In the piezoelectric vibrating gyroscope according to the present invention, since the support 30 has a ring shape, the piezoelectric vibrating gyroscope is symmetrically supported with respect to both the excitation vibration direction and the vibration caused by the Coriolis force. The influence of the support on the characteristics as the vibrating gyroscope is reduced.

Although the above description has been made on the case where the shape of the columnar piezoelectric ceramic is cylindrical, 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, by supporting the vibration nodes (or lines) of the vibrator with a support made of a band-like ring made of a soft fiber or a foam material such as styrene foam or sponge, vibration can be reduced as much as possible. It is supported without any influence, and its surroundings are fastened with a hard holder and fixed to the outer case for fixed support, so it can be stably supported against external vibration and impact. In addition, the vibrator can be fixed at the support portion so as not to shift. further,
Since the soft support is fastened with the hard holder, the apparent contact area between the support and the vibrator is large, but in reality, the support is porous, so the mechanical impedance is good. Will be maintained. Therefore, there is little deterioration of the vibration characteristics due to the support, and there is little influence on the bending vibration in two directions perpendicular to each other, and the influence is symmetric with respect to each vibration direction. Thus, a piezoelectric gyro that can greatly improve reliability with little influence is obtained.

[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 a perspective 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 30 support 31 holder 32 outer case

Claims (1)

(57) [Scope of request for utility model registration] 1. A form a longitudinal band-shaped electrodes on the outer peripheral surface of the columnar piezoelectric ceramics, using belt-shaped electrode pillar
Jo piezoelectric ceramics polarized subjected to, in the piezoelectric vibrating gyroscope for driving and detection by using a bending vibration mode due to the piezoelectric effect of the columnar piezoelectric ceramic, fiber
Alternatively, a band-like ring made of a foam material is
Wear it around the position of the node of the flexural vibration of the mix,
A piezoelectric vibrating gyroscope in which the outer periphery of a band-shaped ring is fastened with a hard holder and supported and fixed in a case.