JPH0921647A - Vibration gyroscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent standing waves from occurring inside a case and downsize a vibration gyroscope by attaching a shield plate for covering at least a part of a vibrator between the inner wall of the case with the vibrator mounted on a substrate and fitted in and the vibrator. SOLUTION: A vibrator 1 is mounted on a substrate 4 while being supported by a support pin 2. The vibrator 1 is fitted into a case M comprising one face of a hexahedron as an opening M1 and including side walls M2 , M3 and a top wall M6 wherein the opening M1 is placed on the substrate 4. In this case, the center of the vibrator 1 is placed at the center between inner faces of the opposite side walls M2 , M3 of the case M and at the center between the inner face 4a of the substrate 4 and the inner face of the top wall M6 of the case M, respectively. In addition, shield plate 18 for covering the entire vibrator 1 is attached between the inner wall M' of the case M with the vibrator 1 mounted on the substrate 4 and fitted in and the vibrator 1 in order to avoid acoustic wave interference. The plate 18 functions as a damper against generated standing waves, thereby reducing sharpness of resonance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating gyro device, and more particularly to a vibrating gyro device in which a vibrator is mounted on a substrate to reduce acoustic interference inside a case to be fitted to achieve miniaturization.

[0002]

2. Description of the Related Art Conventionally, as a vibrating gyroscope for measuring an angular velocity suitable for preventing camera shake of a camera, position and attitude control of various moving bodies such as flying bodies, ships, vehicles and robots, car navigation, etc., FIG. ), (B), it is known that Coriolis force Fc is generated in the y-axis direction when an angular velocity Ω is applied around the z-axis to an object bending in the x-axis direction.

Utilizing this principle, the vibrator 21 supported by the support pins 20 has two surfaces 21a, 21 that are adjacent to each other at a right angle.
The pair of transducers 22, 23 vibrates in the x-axis direction to cause a bending vibration to give a velocity, and the bending caused by the Coriolis force Fc generated in the y-axis direction when the angular velocity Ω is received about the z-axis. A vibration gyro has been proposed which detects a vibration from a pair of transducers 22 and 23 to measure an angular velocity Ω.

There are various types of vibration gyros such as a tuning fork type and a tuning piece type as shown in the figure when focusing on the vibrator. In each case, the transducer 21 has a bending motion in the x-axis direction or the y-axis direction by a transducer. The vibration is caused and the vibration caused by the Coriolis force Fc generated in the y-axis direction or the x-axis direction when the angular velocity Ω is received around the z-axis is detected by the transducer, and the angular velocity Ω is measured. Conventionally, this vibrating gyro has been commercialized by being fitted into the case 25 as follows.

(1) Transducer 2 supported by support pins 20
As shown in FIGS. 27A and 27B, 1 is mounted on a substrate 24 and fitted in a case 25. Hole 2 in case 25
6 and 26 were drilled especially in the lower part to prevent the sound pressure from being sealed. (2) As shown in FIG. 28, the vibrator 21 supported by the support pins 20 is mounted on a substrate 24, and a damper 27 made of a flexible material is provided on the vibrator 24 to fit the case 25 to facilitate vibration. .

In either of the cases (1) and (2), the sensitivity of the vibration gyro is reduced, and therefore the width 2L ₂ and the height h (FIG. 27A) of the case 25 cannot be reduced so much that the air If the speed of sound inside is S and the wavelength of the vibration propagated from the oscillator is λ (= S / f ₀ , where f ₀ is the oscillation frequency of the oscillator 21), a clear design theory has not been published,
Generally, it was 2L ₂ and h> λ / 2.

[0007]

As described above, in the conventional vibrating gyroscope, there is a problem that the efficiency of the vibrating gyroscope is lowered in any of the above (1) and (2). Also,
Recently, there is a demand for perfect sealing with a case because of the demand for magnetic shielding of the vibration gyro.

Therefore, the present invention has been made in view of the above-mentioned difficulties, and an object thereof is to provide a vibration gyro device which prevents generation of standing waves inside the case and is downsized. is there.

[0009]

In order to achieve this object, a vibrating gyro device of the present invention has a vibrator mounted on a substrate in a case having one side of a hexahedron as an opening and a side wall and a top wall. Fit the vibrator so that the opening is placed on the substrate,
A vibrating gyroscope that measures a rotational angular velocity by detecting a bending vibration in a detection vibration direction that is generated by Coriolis force generated when a vibrator is driven to cause bending vibration in the driving vibration direction, A shield plate that surrounds at least a part of the vibrator is mounted between the vibrator and the inner wall of the case where the vibrator is mounted on the substrate and is fitted.

Further, in the vibrating gyro device of the present invention, at least a part of the wall surface of the shield plate is fixed at one end and free at one end. Furthermore, in the vibrating gyro device of the present invention, the shielding plate is made of a thin metal plate. In this vibrating gyro device, by mounting a shield plate that surrounds at least a part of the vibrator between the vibrator and the inner wall of the case where the vibrator is mounted on the substrate and is fitted,
Generation of standing waves is prevented.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which a vibrating gyro device of the present invention is applied to a sound piece type vibrator will be described below with reference to the drawings. As shown in FIGS. 17 (a), (b), and (c), the vibrating gyro device of the present invention is arranged so that, in this embodiment, a vibrator 1 constituted by a rectangular parallelepiped sound piece having a quadrangular cross section is disposed orthogonal to the vibrator 1. A pair of transducers 10a and 10b are attached to two adjacent surfaces 1a and 1b. With this arrangement,
The vibration direction of the vibrator 1 is set to the diagonal mode.

The vibrator 1 is generally made of a metal such as constant elasticity Ni-SPAN-C or Elinba in consideration of temperature characteristics. Also, as a special example, quartz, crystal,
It may be composed of an electrical insulator such as ceramic.
As the constant elastic electric insulator, Young's modulus has a small temperature coefficient and a small linear expansion coefficient, and glass is preferably used. In addition to the constant elasticity of glass, the mechanical Q is large and isotropic, and the glass has the necessary characteristics as a vibrator.

As the transducers 10a and 10b, ceramic piezoelectric elements such as PZT type, ZnO type and BaTiO ₃ type are used. This vibrating gyro device applies electric signals to a pair of transducers 10a and 10b at the same time, applies vibrations from these transducers 10a and 10b to a vibrator 1 in a y-axis direction which is a diagonal direction, and an angular velocity Ω about a z-axis. When receiving, Coriolis force Fc generated in the x-axis direction which is the diagonal direction orthogonal to this diagonal direction
The vibration caused by the pair of transducers 1
The angular velocity Ω is measured by detecting from 0a and 10b.

As shown in FIG. 17 (b), a pair of transducers 10a and 10b are attached to two surfaces 1a and 1b of the vibrator 1 which are adjacent to each other at right angles, and the vibration direction (y direction) of the vibrator 1 is set. When the diagonal mode is set, the voltages Vm appearing on the transducers 10a and 10b during driving at the predetermined frequency f ₀ are equal in the transducers 10a and 10b. That is, the voltages Vm are Vm ₁ = Vm ₂ , respectively. In addition, 4a has shown the neutral line.

On the other hand, as shown in FIG. 17C, the voltage Vc generated by the Coriolis force Fc (x direction) when the angular velocity Ω is applied to the transducer 1 is the transducer 10
The polarities of a and 10b are opposite. That is, Vc ₁ = -Vc _2. In addition, 4b has shown the neutral line. Therefore, when the angular velocity Ω is applied to the vibrator 1, the output signals V ₁ and V ₂ appearing on the transducers 10a and 10b are V ₁ = Vm + Vc V ₂ = Vm−Vc, respectively, and (V ₁ + V ₂ ) / 2 = Vm It is constant, and even when the angular velocity Ω is applied to the transducer 1, the transducer 10
Since the average value signal Vm of the sum of the output signals V ₁ and V ₂ appearing in a and 10b does not change, when the angular velocity is applied to the vibrator as in the conventional case, the voltage and phase on the output side change and the excitation level becomes unstable. Stabilization and instability with respect to external vibrations are avoided.

On the other hand, when an electric signal is applied to the transducer 10a (10b) attached to the vibrator 1, the impedance change of the vibrator 1 including the transducer 10a (10b) changes according to the frequency of the electric signal. It exhibits the characteristics shown in. That is, the vibrator 1 has resistance, capacitance,
Since it has an inductive component, the impedance becomes minimum at the series resonance point and maximum at the parallel resonance point. Furthermore, at both resonance points, there is no capacitance or inductive component, and it is pure resistance.

As shown in FIG. 19, the transducer 1
If the input resistance R is connected in series to 0a (10b) and the drive signal Vin is applied from the input resistance R side, the voltage Vm appearing in the transducer 10a (10b) becomes maximum at the parallel resonance point, and the voltage drop of the input resistance R occurs. Becomes a minimum, becomes a minimum at the series resonance point, the voltage drop of the input resistance R becomes a maximum, and the impedance is only a pure resistance, so that the phase is also in phase with the drive signal Vin of the predetermined frequency f ₀ .

As shown in FIG. 20, the transducer 1
A drive signal Vin is applied from an input resistor R connected in series to 0a (10b), and an average value signal Vm which is an average value (V ₁ + V ₂ ) / 2 of a voltage appearing in the transducer 10a (10b) and a predetermined frequency f ₀ . The drive signal Vin is differentially amplified by the amplifier 15 and the low pass filter or the band pass filter 16 vibrates only the fundamental wave at the resonance point of the vibrator 1 to prevent the overtone from vibrating, and the phase shifter 17
By forming a self-excited oscillation loop circuit that adjusts the phase and positively feeds back, it is possible to configure a drive circuit that drives the vibrator 1 at a resonance frequency at which the vibrator 1 substantially resonates in series. In this way, the transducer 10a (10
The drive signal of b) can be obtained.

The loop gain is set to be larger than 1 at the time of series resonance. Further, the phase shifter 17 is not always necessary, and a positive feedback may be performed by adjusting the phase by adding a filter so that the phase condition is met.
Further, if the output signals V ₁ and V ₂ appearing on both transducers 10 a (10 b) are differentially amplified to obtain a difference signal, then V ₁ −V ₂ = ₂ Vc, and a detection signal of angular velocity Ω is generated.

As described above, the vibrating gyro device of the present invention is
The rotational angular velocity is measured by driving the vibrator 1 to cause bending vibration in the driving vibration direction X, and detecting bending vibration in the detection vibration direction Y caused by the Coriolis force Fc generated when receiving the rotational motion. is there. As shown in FIG. 21, the vibrator 1 is supported by the support pins 2 and mounted on the substrate 4. The vibrator 1 mounted on the substrate 4 has a case M in which one of the hexahedron has an opening M ₁ and side walls M ₂ , M ₃ and a top wall M _6.
Then, the opening M ₁ is fitted so as to be arranged on the substrate 4. In this case, the center of the vibrator 1 is arranged at the center between the inner surfaces of the opposing side walls M ₂ -M ₃ of the case M and the center between the inner surface 4 a of the substrate 4 and the inner surface of the top wall M ₆ of the case M, respectively. It

In this case, the dimension 2Lx between the inner surfaces of the side walls M ₂ -M ₃ of the case M in the driving vibration direction X and the detection vibration direction Y
At least one of the dimensions 2Ly between the inner surface 4a of the substrate 4 and the inner surface of the top wall M ₆ of the case M is set to λ / 4 or less.
Where λ is the wavelength of the vibration propagated from the oscillator, and λ =
S / f ₀ , where S is the speed of sound in the air. In particular, the dimension 2 between the inner surfaces of the side walls M ₂ -M ₃ of the case M in the driving vibration direction X is 2
Lx is set to λ / 4 or less.

[0022]

[Experiment]

[0023]

[Experimental purpose] To measure the acoustic effect of self-excited sound pressure on self-vibration when the vibrator is vibrated in a closed case.

[0024]

[Experimental apparatus] As shown in FIGS. 1 (a) and 1 (b), the top wall 3, the substrate 4, the side frames 7 and 8 and the top wall 3, the substrate 4, and the side frames 7 and 8 are symmetrically moved. Possible slide sidewalls 5, 6
A case M is formed by The vibrator 1 is supported by the support pins 2, mounted on the substrate 4, and fitted in the case M.
The center of the vibrator 1 is arranged at the center of the side walls 5 and 6 of the case M with the dimension 2L ₁ .

[0025]

[Experiment 1] An AC power supply of frequency f ₀ through a resistor R ₀ as shown in FIG. 3 through a pair of piezoelectric transducers 10 and 10 on the vibrator 1 shown in FIGS. V
= Vcosωt, V ′ = − vcosωt is applied. FIG. 4 shows an equivalent circuit of the vibrator 1 that vibrates at this time. Vibrations excited by the pair of transducers 10 and 10 are replaced by a series resonance circuit of an inductance L, a capacitance C and a resistance R. The capacitance C ₀ represents a resonance capacitance.

Here, a pair of transducers 10, 10
The power supplies V and V'applied to V = -V ', that is, the phases are inverted. By doing so, the vibrator 1 is excited in the X-axis direction. Also, the angular frequency ω (= 2π of the applied power source)
f ₀ ) is the series resonance ω ₀ = 1 / √L · C (f ₀ = 30 KHz) shown in the figure. Take dimension 2L ₁ (position of the slide 5 and 6) to the X-axis, the change of the voltage E ₁ of dimension 2L ₁ tap Tp ₁ due to varying, Tp _2, E ₂ (Fig. 4) in the Y-axis, Dimension 2L
When E _L1 / E0 (dB) is taken with reference to the value E ₀ when ₁ = ∞ (that is, point E after slide removal), the characteristic as shown in FIG. 5 is shown. Here, the resonance sharpness Q of the vibration is the minimum when E _L1 / E ₀ is the maximum (near point a in FIG. 5), and the resonance sharpness Q is the resonance when the minimum (near b in FIG. 5). The sharpness Q is the maximum (a state in which it easily vibrates).

[0027]

[Study of Results] From the relationship between the speed of sound and the temperature in the case M shown in Table 1, it is assumed that a standing wave with a sound pressure of λ / 4 is generated at point a in FIG. 5 as shown in FIG. 2 (a). Conceivable. Similarly, at point b, a standing wave having a sound pressure of wavelength λ / 2 is considered to be generated as shown in FIG. From FIG. 2a, the position of minimum sound pressure (λ
The resonance sharpness Q is the minimum when the sound pressure is located at / 4), and the resonance sharpness Q is the maximum when the sound pressure is located at the maximum position (λ / 2) as shown in b. The result is obtained.

[0028]

[Table 1]

[0029]

[Experiment 2] Transducer 1 on vibrator 1 shown in FIG.
AC power source V = vcosωt is applied to terminals 0 and 10 via terminals 9 and 9 through a resistor R _{0 as} shown in FIG. The equivalent circuit at this time is shown in FIG. Unlike the experiment 1, the transducer 1 is excited in the Y-axis direction because the in-phase alternating current V is applied to the pair of transducers 10 and 10. Here, the vibrator 1 is rotated together with the case M as shown in FIG. 6 to apply the rotational angular velocity ω. At that time, if the voltages E ₁ and E ₂ of the taps Tp ₁ and Tp ₂ are measured and the difference voltage E _j = E ₁ −E ₂ is obtained, this difference voltage E _j
Becomes the gyro output. FIG. 8 is a graph in which the value of the difference voltage E _j is plotted by changing the value of the dimension L ₁ while keeping the angular velocity ω constant.

[0030]

[Examination of Results] As can be seen from FIG. 8, the dimension L ₁ = 6 to 7
The difference voltage E _j is maximum between mm and E _j is minimum near the dimension L ₁ = 3 mm. It can be seen that this value correlates with the change in the resonance sharpness Q of Experiment 1. It is easy to understand if a standing wave is generated in the X-axis direction due to a component force in the X-axis direction (shown by a chain line ---) as shown in FIG. 9 even when excitation is performed in the Y-axis direction.

[0031]

[Clarification of operation] From Experiments 1 and 2, the point where the sound pressure generated in case M by self-excitation and disturbing self-excitation is minimum (λ /
When the oscillator 1 is placed in 4), it is Q minimum (self-excitation is disturbed), and when it is placed at the maximum (λ / 2) point, it is Q maximum (self-excitation is not disturbed). I know that there is. This fact seems to be contradictory. There is no literature that clarifies this fact. Therefore, the invention and the like were considered as follows.

An equivalent circuit of the voice piece type vibration gyro is shown in FIG. In FIG. 10, Z _x and Z _Y represent mechanical impedances when the vibrator 1 is vibrating in the X-axis direction and when vibrating in the Y-axis direction, and G _x ⁻¹ and G _Y of the matrix are gyroscopes. The conversion coefficient is shown. When the rotational angular velocity ω is set to ω = 0 and the vibrator 1 is vibrated in the X-axis direction (Experiment 1)
The equivalent circuit of can be expressed as shown in FIG. 11 when the disturbing sound pressure is ignored. Next, when the disturbing sound pressure is taken into consideration, the sound pressure and particle velocity distributions in the case M are shown in FIG. 13, and the wave impedance z _x1 of air due to the sealed sound pressure in the case M is z _x1 = jZ ₀ cotkL ₁ Can be expressed as Where k is the propagation constant of a sound wave in air, Z ₀
Indicates the acoustic impedance of air, respectively. It is considered that the impedance in the direction perpendicular to the length direction of the vibrator 1 is distributed constant in the length direction of the vibrator 1. In order to simplify the equivalent circuit, it is considered that z _x1 is connected in parallel with Z _x as shown in FIG. Now, the oscillator 1 has the inductance L and the capacitance C of the frequency f ₀ (= 1 / √L in FIG. 11).
If it is excited in C), its equivalent circuit is shown in FIG.
Becomes In FIG. 14, R ₀₁ represents resonance resistance, and R ₀₁ ∝
1 / Q ₀ , and Q ₀ is the resonance sharpness (z _x1
Resonance sharpness when is ignored. Oscillator 1
If the value of the dimension L ₁ from the center of the oscillator 1 in FIG. 1 to the side wall of the case M is changed while exciting the frequency f ₀ , the impedance z _x1 = jZ ₀ cotkL ₁ becomes kL ₁ = λ / 4. When z _x1 = 0 (1) When kL ₁ = λ / 2, z _x1 = infinity (2).

That is, in the case of the equation (1) (kL ₁ = λ /
2), the equivalent circuit is as shown in FIG. 15, and z _x1 is in a parallel resonance state, and has little influence on the vibration of the vibrator. Similarly, in the case of equation (2) (kL ₁ = λ / 4), the equivalent circuit is shown in FIG. 16, and the total resonance sharpness Q of this circuit is 1 / Q = 1 / Q ₀ + 1 / Q ′, that is, Q = Since Q ₀ Q '/ (Q ₀ + Q'), the total resonance sharpness Q is lowered. Here, Q ′ indicates the standing wave resonance sharpness in the air in the case M.

Further, from Table 1, when λ / 4, the dimension L ₁ = 3
When mm and λ / 2, the dimension L ₁ = 6 mm. E _L1 / E ₀ is the largest in terms of dimension L ₁ = 3 mm in FIG. 5 from the above results (Q min), it can be seen that the minimum (Q max) when the dimension L ₁ = 6 mm. In these experiments,
Center of the vibrator 1 is arranged in the center of dimension 2L ₁ between the inner surface of the side wall of the case M, since the measurement for the dimensions L ₁ from the transducer 1 to the sidewall inner surface, the dimension between the inner surface of the side wall of the case M is twice that (= 2L ₁ ).

As described above, in FIG. 16, 1 / Q = 1 / Q ₀ + 1 / Q ′ (where Q ₀ is the resonance sharpness Q of the oscillator 1 and Q ′ is the standing wave in the case M). of the resonance sharpness Q), Wakashi Q '"if _{Q 0, Q = Q 0 Q} ' / Q 0 + Q ' can be avoided ≒ Q ₀ becomes wave interference.

According to a feature of the present invention, in order to avoid sound wave interference, the present invention mounts the vibrator 1 on the substrate 4 as shown in FIG. Between,
A shield plate 18 that surrounds the entire vibrator 1 is attached. The resonance sharpness Q ′ is lowered by causing the shield plate 18 to act as a damper against the generated standing wave. In this example, the shield plate 18 that surrounds the whole of the vibrator 1 is attached. However, even if the shield plate 18 surrounds a part of the vibrator 1, the resonance sharpness Q ′ decreases.

Further, as shown in FIGS. 23 (a) and 23 (b), at least a part of the wall surface 18a of the shielding plate 18 is fixed at one end (shown at 19a) and free at one end (shown at 19b) to further improve the damper effect. Goes up. Further, although the shielding plate 18 is generally formed of a resin mold case, the thin metal plate 18c has a wall surface 18a as shown in FIG. 25 and a bottom surface 18b having a U-shaped cross section, and a bottom surface 1 as shown in FIG.
It is also possible to mount 8b on the substrate 4.

As a specific example, in the configuration shown in FIGS. 24 and 25, the frequency f ₀ of the sound piece type vibrator 1 is 30 KHz, the size of the case M is 2L ₁ = 6.0 mm, h = 3.4 mm, and the shielding plate 18 is As a result of carrying out with the dimension w = 2.8 mm, the sensitivities before covering the case M and after covering the case M are
It was almost the same. That is, the sound wave interference inside the case M was almost zero.

According to the conventional vibrating gyro device shown in FIG. 28, when the size of the case 25 is 2L 2 = 6.0 mm, the sound wave interference is maximized and the sensitivity is significantly lowered. In addition,
In the above embodiment, the driving vibration direction is set to X and the detection vibration direction is set to Y, but it may be set in the opposite direction. Example Further, in the above embodiment is arranged the center of the vibrator 1 in the center of dimension 2L ₁ between the inner surface of the side wall of the case M, was measured for the dimension L ₁ from the transducer 1 to the sidewall inner surface (Lx in FIG. 21)
As described above, the center of the vibrator 1 is placed on the inner surface 4 of the substrate 4.
The same effect can be obtained when it is arranged in the center of the dimension 2Ly between a and the inner surface of the top wall M ₆ of the case M and applied to the dimension between the vibrator 1 and the inner surface of the top wall M _6. Is.

Further, in the above embodiment, an example in which the vibration gyro device is applied to a sound piece type using a rectangular parallelepiped rectangular parallelepiped vibrator has been described, but the vibration gyro device of the present invention has an n-gonal cross section (n is 3). (Or 5 or more), it can be applied to a polyhedron tone piece type, and can be equally applied to the case of applying to a tuning fork type. In this case, the above-mentioned x-axis direction and y-axis direction refer to the x-axis direction component and the y-axis direction component of the n-sided cross section. Further, in the above embodiment, the pair of transducers are attached to the two adjacent faces of the vibrator which are composed of rectangular parallelepiped sound pieces each having a quadrangular cross section, but the three or more transducers are attached and driven.・ Detection can be performed.

[0041]

As is apparent from the above description, according to the vibrating gyro device of the present invention, it is possible to prevent standing waves from being generated inside the case, reduce acoustic interference, and achieve miniaturization. .

[Brief description of drawings]

1A and 1B are an explanatory top view and an explanatory plan view, respectively, of a vibration gyro device assembled and verified as an experimental device.

FIG. 2A and FIG. 2B are characteristic diagrams showing a relationship between a vibrator of a vibrating gyro device, dimensions of a case, and standing waves, respectively.

FIG. 3 is a circuit diagram for exciting a vibrator of the vibration gyro device in the X-axis direction.

FIG. 4 is an equivalent circuit diagram of a vibrator excited in the X-axis direction.

FIG. 5 is an output voltage characteristic diagram when the dimensions of the case are changed.

FIG. 6 is a circuit diagram for exciting a vibrator of the vibrating gyro device in the Y-axis direction.

FIG. 7 is an equivalent circuit diagram of a vibrator excited in the Y-axis direction.

FIG. 8 is an output voltage characteristic diagram when the dimensions of the case are changed.

FIG. 9 is an explanatory diagram showing a component force in the X-axis direction generated when a vibrator of the vibrating gyro device is excited in the Y-axis direction.

FIG. 10 is an equivalent circuit diagram of the vibration gyro device.

FIG. 11 is an equivalent circuit diagram of the vibration gyro device when the vibrator of the vibration gyro device is vibrated in the X-axis direction and the interfering sound pressure is ignored.

12 is an equivalent circuit diagram of the vibration gyro device, which is drawn by simplifying the equivalent circuit diagram shown in FIG.

FIG. 13: Sound pressure in the case, taking into account the disturbing sound pressure,
The figure which shows distribution of particle velocity.

FIG. 14 shows a vibrator of the vibration gyro device with a frequency f ₀ (= 1 / √L) of the inductance L and the capacitance C in FIG.
The equivalent circuit diagram of the vibration gyro device when excited by C).

FIG. 15 is an equivalent circuit diagram of the vibration gyro device when the value of the dimension is changed and the value is a specific value.

FIG. 16 is an equivalent circuit diagram of the vibration gyro device when the dimension value is changed and the value is a specific value.

17 (a) is a schematic perspective view of a vibrator and a transducer of the vibration gyro device according to the present invention, FIG.
17B is an explanatory diagram showing the vibration direction and voltage of the transducer when the vibration gyro device shown in FIG. 17A is driven, and FIG. 17C is a graph showing the angular velocity of the vibration gyro device shown in FIG. Explanatory drawing which shows the generation | occurrence | production direction of Coriolis force, and voltage.

FIG. 18 is a characteristic diagram showing the relationship between the impedance change of a transducer including a transducer used in a vibration gyro device and the frequency of an excitation signal.

FIG. 19 is a circuit diagram showing a concept of driving / angular velocity detection of the vibration gyro device.

FIG. 20 is a circuit diagram showing the principle of a drive circuit of a vibration gyro device.

FIG. 21 is an explanatory diagram showing dimensions of a vibrator and a case of the vibration gyro device.

FIG. 22 is a vibrator of a vibration gyro device according to the present invention,
Explanatory drawing which shows a case and a shielding plate.

FIG. 23 (a) shows a vibrator, a case, and a shield plate of the vibrating gyro device according to the present invention, an explanatory view when the wall surface of the shield plate is fixed at one end and free at one end;
FIG. 23 (b) is a perspective view when the shield plate of the vibrating gyro device according to the present invention is fixed at one end and free at one end.

FIG. 24 is a vibrator of the vibration gyro device according to the present invention;
Explanatory drawing which shows the dimension of a case and a shielding plate.

FIG. 25 is a perspective view showing the dimensions of the shielding plate of the vibrating gyro device according to the present invention.

26 (a) and 26 (b) are respectively a schematic perspective view and a plan view of a vibrator and a transducer of a conventional vibrating gyro device.

27 (a) and 27 (b) are a plan explanatory view and a bottom explanatory view showing a state in which the case is fitted in a case of a conventional vibrating gyro device, respectively.

FIG. 28 is an explanatory plan view showing a state in which a case of another conventional vibration gyro device is fitted.

[Explanation of symbols]

1 ...... vibrator 4 ...... substrate X ...... driving vibration direction Y ...... detecting vibration direction M ...... case M '...... inner wall M ₁ ...... opening M _2, M ₃ ...... sidewall M ₆ ...... top wall Fc: Coriolis force 18: Shielding plate 18a: Wall surface 18c: Metal thin plate 19a: One end fixed 19b: One end free

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshitaka Kanano 2-1-1, Oda Sakae, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture, Showa Electric Wire & Cable Co., Ltd. (72) Takeo Yokoyama, 2 Sakae Oda, Kawasaki-ku, Kanagawa No. 1-1 No. 1 Showa Electric Cable Co., Ltd.

Claims (3)

[Claims] 1. A vibrator is mounted on a substrate, and the vibrator is fitted in a case consisting of a side wall and a top wall with one of the hexahedrons as an opening and the opening is arranged on the substrate. A vibration gyro that measures the rotational angular velocity by driving the vibrator to cause bending vibration in the driving vibration direction and detecting bending vibration in the detection vibration direction caused by the Coriolis force generated when a rotational motion is received. And a shield plate surrounding at least a part of the vibrator between the vibrator and the inner wall of the case on which the vibrator is mounted on the substrate to be fitted, and a vibrating gyro device. . 2. The at least part of the wall surface of the shielding plate is fixed at one end and free at one end.
The described vibration gyro device. 3. The vibrating gyro device according to claim 1, wherein the shielding plate is made of a thin metal plate.