JPH09113280A - Vibrational gyro - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a gyro having excellent responsiveness without changing the vibrator section nor circuit configuration of the gyro. SOLUTION: A vibrational gyro 10 is incorporated with a vibrating body 12 constituted in, for example, an equilateral triangular prism. Piezoelectric elements 14a, 14b, and 14c are respectively formed on the side faces of the vibrating body 12. The elements 14a, 14b, and 14c respectively contain piezoelectric plates 16a, 16b, and 16c and electrodes 18a and 20a, 18b and 20b, and 18c and 20c are respectively formed on both surfaces of the plates 16a, 16b, and 16c. The piezoelectric strain constants d33 of the elements 14a, 14b, and 14c are set at >=150×10<-12> (c/N). When the vibrating body 12 is formed of a piezoelectric material, the piezoelectric strain constant d33 of the vibrating body 12 is set at >=150×10<-12> (c/N).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating gyro, and more particularly to a vibrating gyro for detecting a rotational angular velocity by utilizing bending vibration of a vibrating body.

[0002]

2. Description of the Related Art FIG. 1 is a perspective view showing an example of a vibrating gyroscope as a background of the present invention, and FIG. 2 is a sectional view thereof. The vibrating gyroscope 10 includes, for example, a regular triangular prism-shaped vibrating body 12. The vibrating body 12 is formed of a material that generally causes mechanical vibration, such as elinvar, iron-nickel alloy, quartz, glass, crystal, and ceramic.

Piezoelectric elements 14a, 14b and 14c are formed on three side surfaces of the vibrating body 12, respectively. The piezoelectric element 14a is a piezoelectric plate 16 made of piezoelectric ceramic or the like.
a. On both surfaces of this piezoelectric plate 16a, electrodes 18a,
20a is formed. Then, one electrode 20a is bonded to the vibrating body 12. Similarly, the piezoelectric elements 14b, 14
c includes piezoelectric plates 16b and 16c. These piezoelectric plates 1
Electrodes 18b and 20b and electrodes 18c and 20c are formed on both surfaces of 6b and 16c. Then, one electrodes 20b and 20c of these piezoelectric elements 16b and 16c are bonded to the vibrating body 12.

In order to use this vibrating gyroscope 10, as shown in FIG. 3, a resistor 22 is attached to the piezoelectric elements 14a and 14b.
a and 22b are connected. These resistors 22a, 22b
The oscillation circuit 24 is connected between the piezoelectric element 14c and the piezoelectric element 14c. From the oscillation circuit 24, the two piezoelectric elements 14a, 14
A drive signal is given to b, and the output signal from the piezoelectric element 14c is fed back to the oscillation circuit 24. In addition, the piezoelectric element 14
The a and 14b are connected to the input ends of the differential circuit 26. The output signal of the differential circuit 26 is detected by the synchronous detection circuit 28 in synchronization with the signal of the oscillation circuit 24. Synchronous detection circuit 28
Is connected to the smoothing circuit 30, and the smoothing circuit 30 is DC
It is connected to the amplifier 32.

The vibrating gyro 10 is self-excited and driven by an oscillating circuit 24, and the vibrating body 12 flexurally vibrates in a direction orthogonal to the surface on which the piezoelectric element 14c is formed. At this time, the output signals of the piezoelectric elements 14a and 14b are the same, and the differential circuit 2
No signal is output from 6. In this state, the vibrating body 12
When rotated about the axis of, the direction of flexural vibration of the vibrating body 12 changes due to the Coriolis force. This causes a difference in the output signals of the piezoelectric elements 14a and 14b, and the differential circuit 2
A signal is output from 6. This signal is the synchronous detection circuit 2
At 8, the signal is detected in synchronization with the signal of the oscillator circuit 24. The output signal of the synchronous detection circuit 28 is smoothed by the smoothing circuit 30 and further amplified by the DC amplifier 32. This DC amplifier 32
Is an output signal corresponding to a change in the vibration direction of the vibrating body 12, that is, a Coriolis force. Therefore, the rotational angular velocity applied to the vibration gyro 10 can be detected by measuring the output signal of the DC amplifier 32.

In such a vibration gyro 10, good responsiveness is required. That is, it is required to shorten the time from when the rotational angular velocity is applied to the vibration gyro 10 until the signal corresponding thereto is output. In order to meet such requirements, for example, it is conceivable to downsize the vibration gyro 10 or increase the frequency of bending vibration of the vibrating body 12.

[0007]

However, when the vibration gyro is downsized or the frequency is increased, there are drawbacks such that the sensitivity is significantly lowered and the S / N ratio is deteriorated.
Furthermore, if such a method is adopted, it is necessary to change the circuit configuration and the circuit constants for driving and detection.

Therefore, a main object of the present invention is to provide a vibrating gyro having good responsiveness without changing the vibrator section or the circuit configuration.

[0009]

According to the present invention, there is provided a vibrating gyroscope including a columnar vibrating body and a plurality of piezoelectric elements formed on a side surface of the vibrating body.
₃₃ is a vibrating gyro, wherein ₃₃ is set to d ₃₃ = 150 × 10 ⁻¹² (c / N) or more. Further, according to the present invention, in a vibrating gyro that includes a columnar vibrating body formed of a piezoelectric material and a plurality of electrodes formed on a side surface of the vibrating body, the piezoelectric strain constant d ₃₃ of the vibrating body is set to d ₃₃ = 150 x 10
^-12 (c / N) or more, which is a vibrating gyro.

Piezoelectric strain constant d of the piezoelectric portion of the vibrating gyro
_{When 33} was changed and the characteristics were measured, it was found that the response was improved by increasing the piezoelectric strain constant.
In particular, it was found that the response of the vibration gyro changes extremely at the boundary of d ₃₃ = 150 × 10 ^-12 (c / N).

[0011]

According to the present invention, the piezoelectric strain constant d ₃₃ of the piezoelectric portion of the vibrating gyro is d ₃₃ = 150 × 10
By setting it to be ^-12 (c / N) or more, good responsiveness can be obtained.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments of the invention with reference to the drawings.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As an example of a vibrating gyroscope according to the present invention, one having a structure shown in FIGS. 1 and 2 can be considered. In this vibrating gyro 10, the piezoelectric elements 14a,
The piezoelectric strain constant d ₃₃ of 14b and 14c is d ₃₃ = 150 × 1
It is set to be ^0-12 (c / N) or more. Here, the piezoelectric strain constant d ₃₃ is a constant indicating the amount of electric charge generated when a force of 1 N is applied to the piezoelectric element.

In such a vibrating gyro 10, the piezoelectric strain constants d ₃₃ of the piezoelectric elements 14a, 14b, 14c are changed to give a rotational angular velocity to the vibrating gyro 10, and the differential circuit 2
The delay of the signal obtained from 6 was measured. Specifically, the vibration gyro 10 was subjected to rotational vibration such that the rotation direction was reversed at 30 Hz, and thereby the changing angular velocity was applied to the vibration gyro 10. Then, the output signal of the differential circuit 26 was measured, and the signal corresponding to the given rotational angular velocity was detected. Then, the phase delay of the output signal of the differential circuit 26 with respect to the given rotational angular velocity was measured, and the result is shown in FIG.

As can be seen from FIG. 4, the piezoelectric strain constant d
_{When 33} becomes smaller than d ₃₃ = 150 × 10 ^-12 (c / N), the phase delay rapidly increases. That is, it takes a long time after the rotational angular velocity is applied to the vibration gyro 10 until the main force signal of the differential circuit 26 is obtained. Therefore,
A vibrating gyroscope 10 using a piezoelectric element having a piezoelectric strain constant larger than this point is within the scope of the present invention. That is,
In the vibrating gyroscope 10 using the piezoelectric element of d ₃₃ = 150 × 10 ⁻¹² (c / N) or more, the time from the addition of the rotational angular velocity to the output of the corresponding signal is short and the responsiveness is low. Get better

The vibrating gyro 10 may be a vibrating body 12 having a rectangular prism shape as shown in FIGS. 5 and 6. In the vibrating gyroscope 10 shown in FIG. 5, the piezoelectric elements 14a, 14b, 14 are provided on the four side surfaces of the vibrating body 12.
c and 14d are formed. In this vibrating gyro 10, for example, the opposing piezoelectric elements 14a and 14c are used for driving, and the other opposing piezoelectric elements 14b and 14d are used.
Is used for detection. In such a usage method, the vibrating body 12 flexurally vibrates in the direction orthogonal to the surfaces on which the piezoelectric elements 14a and 14c are formed. In addition, the adjacent piezoelectric element 14
Alternatively, a and 14b may be used for driving and rotation angular velocity detection, and another adjacent piezoelectric elements 14c and 14d may be used for feedback. In this case, the output signals of the piezoelectric elements 14c and 14d are combined and fed back to the oscillation circuit 24. In such a usage method, the vibrating body 12 flexurally vibrates in the direction connecting the ridge lines facing each other.

Further, in the vibrating gyroscope 10 shown in FIG. 6, piezoelectric elements 14a and 14b are formed on the adjacent side surfaces of the vibrating body 12 having a rectangular prism shape. This vibrating gyro 1
At 0, the drive signals are given to the piezoelectric elements 14a and 14b, and the output signals thereof are combined to generate the oscillation circuit 24.
Will be returned to At the same time, the output signals of the piezoelectric elements 14a and 14b are connected to the differential circuit 26. Also in this vibrating gyro 10, the vibrating body 12 flexurally vibrates in the direction connecting the opposing ridgelines.

Also for these vibrating gyros 10, the piezoelectric strain constant d ₃₃ of each piezoelectric element is set to d ₃₃ = 150 × 10 ⁻¹²
By setting it to (c / N) or more, a vibration gyro with good responsiveness can be obtained. Thus, the vibrating body 1
The shape of 2 is not limited to a regular triangular prism, but can be various pillars.

Further, as shown in FIGS. 7 and 8, the vibrating body 12 may be formed of a piezoelectric material. In the vibrating gyro 10, the vibrating body 12 is formed in a columnar shape. Six electrodes 40a to 40f are formed on the side surface of the vibrating body 12. And the three electrodes 40b, 40d,
Both ends of 40f are connected and used as a common electrode.
The vibrating body 12 is polarized between the electrodes 40a, 40c, 40e and the common electrode. And the electrodes 40a, 40c
To the oscillation circuit 24, and the output signal of the electrode 40e is fed back to the oscillation circuit 24. In addition, the output signals of the electrodes 40 a and 40 c are input to the differential circuit 26.

In this vibrating gyro 10, the piezoelectric strain constant d ₃₃ of the vibrating body 12 is d ₃₃ = 150 × 10 ^-12 (c
/ N) or more. Even with the vibrating gyroscope 10 using such a vibrating body 12, it is possible to obtain good responsiveness as in the case where the piezoelectric element is formed on the side surface of the vibrating body.

Further, as shown in FIGS. 9 and 10,
The cylindrical vibrating body 12 may be used. This vibrating body 12
Is also made of a piezoelectric material. Then, the vibrating body 12
Three electrodes 42a, 42b, 42c are formed on the outer surface of the. In addition, the common electrode 4 is formed on the inner surface of the vibrating body 12.
4 are formed. The vibrating body 12 includes electrodes 42a, 42b,
A polarization process is performed between 42c and the common electrode 44. Also in this vibrating gyro 10, the oscillation circuit 24 is connected between the electrodes 42a and 42b and the electrode 42c. And the electrode 42
A drive signal is given to a and 42b, and the output signal from the electrode 42c is fed back to the oscillation circuit 24. Further, the electrode 42
The output signals of a and 42b are input to the differential circuit 26.

Also in such a vibration gyro 10,
The piezoelectric strain constant d ₃₃ of the vibrating body 12 is d ₃₃ = 150 × 10
^-12 (c / N) or more is set. Even with the vibrating gyroscope 10 using such a vibrating body 12, it is possible to obtain good responsiveness as in the case where the piezoelectric element is formed on the side surface of the vibrating body.

As described above, even when the vibrating body 12 is made of the piezoelectric material, the shape of the vibrating body 12 can be arbitrarily selected. For example, as shown in FIGS. 1, 5 and 6, the vibrating body 12 may be formed in a regular triangular prism shape or a quadrangular prism shape. In this case, an electrode is formed on the side surface of the vibrating body 12 instead of the piezoelectric element. Also in such a vibration gyro 10, the piezoelectric strain constant d of the vibrating body 12 is
Needless to say, ₃₃ is set to be d ₃₃ = 150 × 10 ⁻¹² (c / N) or more.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a vibrating gyroscope which is a background of the present invention and to which the present invention is applied.

FIG. 2 is a sectional view of the vibrating gyroscope shown in FIG.

FIG. 3 is a block diagram showing a circuit for using the vibrating gyroscope shown in FIG. 1;

FIG. 4 is a graph showing the results of measuring the phase delay of the signal with respect to the rotational angular velocity by changing the piezoelectric strain constant of the piezoelectric element in the vibration gyro having the shape shown in FIG.

FIG. 5 is a sectional view showing another example of a vibration gyro to which the present invention is applied.

FIG. 6 is a sectional view showing still another example of a vibration gyro to which the present invention is applied.

FIG. 7 is a perspective view showing another example of a vibration gyro to which the present invention is applied.

8 is a cross-sectional view of the vibrating gyro shown in FIG.

FIG. 9 is a perspective view showing still another example of a vibration gyro to which the present invention is applied.

10 is a cross-sectional view of the vibrating gyro shown in FIG.

[Explanation of symbols]

 10 vibrating gyro 12 vibrating body 14a, 14b, 14c piezoelectric element 24 oscillation circuit 26 differential circuit 28 synchronous detection circuit 30 smoothing circuit 32 DC amplifier 40a-40f electrode 42a, 42b, 42c electrode 44 common electrode

Claims (2)

[Claims] 1. A vibrating gyroscope including a columnar vibrating body and a plurality of piezoelectric elements formed on a side surface of the vibrating body, wherein a piezoelectric strain constant d ₃₃ of the piezoelectric element is d ₃₃ = 150 × 10.
^-12 (c / N) or more, vibrating gyro. 2. A vibrating gyroscope including a columnar vibrating body made of a piezoelectric material and a plurality of electrodes formed on a side surface of the vibrating body, wherein a piezoelectric strain constant d ₃₃ of the vibrating body is set to d ₃₃ = 150 × 10
^-12 (c / N) or more, vibrating gyro.