JPH0527614U - Piezoelectric vibration gyro - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a piezoelectric vibration gyro that has little influence on flexural vibration and can be stably supported. The piezoelectric vibrating gyroscope according to the present invention comprises a columnar piezoelectric ceramic 20 having a plurality of strip electrodes 21 coated in the length direction.
And a cylindrical support 30 having a groove 23 formed at a position corresponding to a contact point of vibration in a bending vibration mode, and a thin ring 22 made of a soft elastic body fitted in the groove 23. To do.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is a so-called gyroscope used for a posture control of a moving body such as a ship or an automobile and equipment mounted on the moving body itself, a navigation system of an automobile, etc. The present invention relates to a piezoelectric vibrating gyro, and more particularly to a piezoelectric vibrating gyro using a piezoelectric ceramic cylinder vibrator.

[0002]

[Prior Art]

 A piezoelectric vibrating gyroscope is a gyroscope that utilizes a mechanical phenomenon that produces a Coriolis force in a direction perpendicular to the direction of vibration when a rotating angular velocity is applied to a vibrating object. In a vibration system configured to be able to excite and detect in two directions orthogonal to each other, with one vibration being excited, the vibrator itself is centered on the line where the two vibrating planes intersect. When rotated, a force acts in a direction perpendicular to this vibration due to the action of the Coriolis force described above, 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, with the input voltage kept constant, the magnitude of the output voltage proportional to the magnitude of this vibration changes to the rotational angular velocity. You can ask for it.

FIG. 5 is a schematic structural view of a conventional example of a piezoelectric vibrating gyro. Piezoelectric ceramic thin plates 8 and 9 in which electrodes are formed on both surfaces of a square prismatic metal prism 7 adjacent to each other and polarized in the thickness direction. Are joined. The metal prism 7 can flexurally vibrate in two directions perpendicular to each other at substantially the same resonance frequency. When a voltage having a frequency equal to this resonance frequency is applied to the piezoelectric ceramic thin plate 8, the piezoelectric ceramic thin plate 8 is bonded. Flexural vibration occurs in the direction in which the surface becomes uneven. In this state, no voltage is generated in the piezoelectric ceramic thin plate 9 of the metal prism 7, but when the metal prism 7 is rotated about the length direction, the metal prism 7 is bonded to the piezoelectric ceramic thin plate 9 by the action of Coriolis force. Flexural vibration occurs in the direction in which the surface becomes uneven, and a voltage proportional to the rotational angular velocity is generated in the piezoelectric ceramics 9.

In FIG. 5, a supporting wire made of a thin metal wire is formed in a central portion of the metal surfaces facing each other at a position of about 22.4% of the entire length from one end surface of the metal prism 7 in the length direction. 10, 10 'are welded. Further, a supporting wire 11 made of a thin metal wire is formed at a position approximately 22.4% of the entire length from the other end surface of the metal wire, which is orthogonal to the surface on which the metal wire is welded and which is perpendicular to the surface at the center of the facing metal surface. , 11 'are welded. The portion where these metal wires are welded is a node of vibration for the 1-wavelength bending resonance vibration mode of the metal prism 7 and is supported by a thin metal wire so as to minimize the influence on each bending vibration orthogonal to each other. ing.

By the way, the support lines 10 and 10 ′ support the node of vibration almost ideally for bending vibration in the direction of the arrow.

[0006]

[Problems to be solved by the device]

 However, as shown in FIG. 6, bending strains are generated in the support lines 11 and 11 'at this time, which affects the bending vibration in the direction of the arrow.

On the other hand, the supporting wires 10 and 10 ′ similarly affect the bending vibration in the direction (length direction) perpendicular to the arrow. In order to reduce the effect on flexural vibration, it is necessary to make the diameter of the support wire as thin as possible.However, making the support wire thin reduces the vibration resistance and shock resistance of the vibrator itself. is there.

Further, in the conventional piezoelectric vibrating gyro, the vibrator is composed of a single piezoelectric ceramic, and the strip electrodes formed on the outer peripheral surface of the vibrator are formed by screen printing or vapor deposition. Welding or soldering support wires made of metal wires has problems in terms of vibration resistance and shock resistance.

The object of the present invention is to eliminate the above-mentioned drawbacks of the conventional supporting means of the piezoelectric vibrating gyroscope, to have little influence on the flexural vibration in the longitudinal direction, and to give different influences. An object of the present invention is to provide a piezoelectric vibrating gyro that is symmetric with respect to the vibrating direction and has little influence on the flexural vibration characteristics of the piezoelectric vibrating gyro.

Another object of the present invention is to provide a piezoelectric vibrating gyro that can be stably supported by using a piezoelectric vibrator in which a strip-shaped electrode is formed on the outer peripheral surface of a columnar vibrator made of a single piezoelectric ceramic. .

[0011]

[Means for Solving the Problems]

 According to the present invention, the columnar piezoelectric ceramics in which a plurality of strip electrodes are coated in the length direction are provided, and the rotational angular velocity is detected by utilizing the columnar piezoelectric ceramics as a vibrator by utilizing the bending vibration mode by the piezoelectric lateral effect. The piezoelectric vibrating gyro is provided with a cylindrical support having a groove formed at a position corresponding to a node of vibration in the bending vibration mode, and the columnar piezoelectric ceramic is formed by a thin ring made of a soft elastic body fitted in the groove. A piezoelectric vibrating gyro is obtained which is characterized in that is provided inside the tubular support.

[0012]

【Example】

 Hereinafter, a piezoelectric vibrating gyroscope according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a piezoelectric vibrating gyroscope according to an embodiment of the present invention, and FIG. 2 shows a columnar piezoelectric ceramic 20 used in this piezoelectric vibrating gyroscope. The piezoelectric lamix cylinder 20 is provided with strip electrodes 21 in parallel with the length direction at positions equally dividing the circumference on the outer peripheral surface. The strip electrode 21 can be easily obtained by directly forming by curved screen printing, or by removing unnecessary portions of the electrode formed on the entire surface by plating or the like by photoetching.

The piezoelectric ceramic cylinder 20 shown in FIGS. 1 and 2 is polarized by using the strip electrodes 21, and then a portion of these strip electrodes 21 is subjected to an AC voltage approximately equal to the resonance frequency of bending vibration. When the piezoelectric ceramic cylinder 20 is rotated around the rotation axis in a state in which the bending vibration is excited by applying a force, a Coriolis force is generated in a direction perpendicular to the vibration direction and is applied to a part of the strip electrode 21. A voltage proportional to the rotational angular velocity is generated.

FIG. 3 shows a cylindrical support 30 used in the piezoelectric vibrating gyro of FIG. The support 30 is a cylindrical support made of a soft elastic body in which grooves 23 parallel to the circumference are formed at two locations corresponding to the nodes of vibration in one-wavelength resonance of the bending vibration mode. Referring to FIG. 1, after inserting the thin ring 22 as shown in FIG. 4 into the groove 23 of the cylindrical support 30, the whole is inserted into the outer case 24 and fixed.

In general, in order to support a resonator that resonates without affecting vibration as much as possible, it is necessary to support a node (or line) of a vibration node with a soft material. However, in order to support it stably against external vibrations and shocks, it is necessary to fix it so that the vibrator does not shift at the support part. In the support structure of the present invention, since the thin ring 22 made of an elastic body is inserted into the cylindrical support tool 30 made of a soft elastic body such as soft silicone rubber as described above, even if an external vibration or shock is applied. The vibrator of the piezoelectric ceramic cylinder 20 can be stably supported so as not to shift. Further, in the piezoelectric vibrating gyro of the present invention, since the support is ring-shaped, it is supported symmetrically with respect to both the vibration direction of the excitation vibration and the vibration due to the Coriolis force, which gives characteristics to the piezoelectric vibration gyro. The influence of support is reduced.

Although the above description has been made on the case where the columnar piezoelectric ceramics are cylindrical, the piezoelectric ceramics can be configured in the same manner even if they are square prisms having a square cross section or other prisms having a regular polygonal cross section.

[0017]

[Effect of the device]

 As described above, according to the piezoelectric gyro of the present invention, there is little variation in the vibration characteristics due to the support, and the influence on the flexural vibration in two directions orthogonal to each other is symmetrical with respect to each vibration direction. Moreover, since the cylindrical support is made of a soft elastic material such as silicon rubber, it is possible to secure stable characteristics that are less affected by impact.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a piezoelectric vibrating gyro according to the present invention.

FIG. 2 is a perspective view of the piezoelectric ceramic cylinder of FIG.

3 is a partially cutaway perspective view of the cylindrical support of FIG.

4 is a perspective view of the thin ring of FIG. 1. FIG.

FIG. 5 is a perspective view showing a configuration of a conventional example of a piezoelectric vibrating gyro.

FIG. 6 is a diagram for explaining the operation of the piezoelectric vibration gyro of FIG.

[Explanation of symbols]

 7 Metal Prism 8, 9 Piezoelectric Ceramics Thin Plate 10 (10 '), 11 (11') Metal Support Wire 20 Piezoelectric Ceramics Column 21 Strip Electrode 22 Thin Ring 23 Groove Formed in Supporting Tool 24 Outer Case 30 Supporting Tool

Claims (1)

[Scope of utility model registration request] 1. A piezoelectric vibration comprising a columnar piezoelectric ceramic in which a plurality of strip-shaped electrodes are coated in the lengthwise direction, and the angular vibration velocity is detected by utilizing a bending vibration mode by the piezoelectric lateral effect of the columnar piezoelectric ceramic as a vibrator. The gyro includes a tubular support having a groove formed at a position corresponding to a node of vibration in the bending vibration mode, and the columnar piezoelectric ceramic is tubularly formed by a thin ring made of a soft elastic body fitted in the groove. A piezoelectric vibrating gyro provided in a support.