JP2003279356A - Tuning-fork vibrating gyroscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tuning-fork vibrating gyroscope which lowers an unnecessary signal which is generated when vibration is applied from outside. <P>SOLUTION: The tuning-fork vibrating gyroscope is provided with a tuning- fork vibrator 1 having two arms 2, 3 and a base 4; and a supporting board 6 which supports the base 4, and performs in-plane vibration of the tuning-fork vibrator 1 as driving-side vibrator 1 and torsional vibration, at which the tuning- fork vibrator 1 and the supporting board 6 are integrated as detection side vibration. The unnecessary signal generated by the vibration from outside is lowered by making an absolute value of the difference between the resonance frequency of the driving side vibration and the resonance frequency of the detection side vibration the upper limit value or larger of a required frequency characteristic. It is favorable that the absolute value of the difference should be three times or more as much as the upper limit value of the required frequency characteristic. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gyro used for detecting a rotational angular velocity, and more particularly to a tuning fork type vibration gyro having two arms and a base which are integrally formed.

[0002]

2. Description of the Related Art A gyroscope is used as a means for confirming the position of a moving body such as an aircraft, a large ship, a space satellite, etc., and recently, in a field for consumer use, a car navigation system, a camera shake detecting device such as a video camera, etc. It is also used for etc. In a gyroscope like this,
Research and development of a tuning fork type piezoelectric vibrating gyro having a structure in which two arms and a base that supports both arms are integrally formed of a piezoelectric single crystal is underway.

FIG. 16 shows, for example, Japanese Patent Application Laid-Open No. 9-269228.
It is a block diagram of the tuning fork type vibration gyro shown in Japanese Patent Publication.
In the figure, 1 is a tuning fork type vibrator, and the tuning fork type vibrator 1
Is two arms 2, 3 and a base 4 supporting them
Have. The arms 2, 3 and the base 4 are made of LiTa.
The piezoelectric single crystal such as O ₃ or LiNbO ₃ is integrally processed. The tuning fork type vibrator 1 is supported by connecting the base 4 of the tuning fork type vibrator 1 to the support substrate 6 provided on the stem 5.

A supporting arm 7 having a substantially U-shaped cross section
Is inserted into the slit of the support substrate 6 formed so as to include the center of rotation of the support substrate 6, and is flexibly attached to the support substrate 6 via the adhesive layer 8 made of a rubber-like elastic body. There is. Protrusions are provided at both ends of the support arm 7, and the protrusions are inserted into the holes formed in the stem 5.

A cap 9 is provided to cover and protect these members. The cap 9 and the stem 5 form a case 10. It should be noted that the circuit board 11 (see FIG. 20) including a drive circuit that excites drive vibration and a detection circuit that processes a detection signal, which will be described later, is attached to the stem 5
It is also possible to provide the circuit board 11 in the case 10 by providing it on the cap 9 and / or the cap 9.

Such a tuning fork type vibrator 1 is shown in FIG.
As shown in (a) and (b), there are fx mode vibration (in-plane vibration) and fy mode vibration (plane vertical vibration). When drive vibration (in-plane vibration) is excited, detection vibration (plane vertical vibration) occurs when a rotational angular velocity is applied. Therefore, an output signal proportional to the magnitude of this vibration is detected,
Calculate the angular velocity.

By the way, the driving vibration (in-plane vibration) direction is X.
Direction, the detected vibration (plane vertical vibration) direction is the Y direction, and the rotation axis direction perpendicular to both directions is the Z direction. Especially, when external vibration or shock is applied in the X direction and the Y direction, the tuning fork type vibration is generated. The child 1 is integrally formed with the support substrate 6 as shown in FIG.
The rocking motion as shown in (b) is caused.

In this case, as shown in FIGS. 19A and 19B, the tip of the tuning fork type vibrator 1 (arms 2 and 3) first collides with the inner wall of the case 10, that is, the stem 5 or the cap 9. Will be done. When the circuit board 11 is provided on the inner wall of the case 10, as shown in FIG.
As shown in (b), the tip of the tuning fork type vibrator 1 (arms 2 and 3) first collides with the circuit board 11. here,
When vibration or shock from the outside is large, the tuning fork type vibrator 1 is broken and broken at the base of the arms 2 and 3 due to this collision, and there is a problem that the function of the sensor cannot be fulfilled.

Various measures have been proposed to protect the tuning fork type vibrator from external vibration or shock (eg, Patent Document 1 (Prior Art 1) and Patent Document 2 (Prior Art 2).
reference).

[0010]

[Patent Document 1] JP-A-5-18755

[Patent Document 2] Japanese Patent Laid-Open No. 7-243857

[0011]

In Conventional Example 1, a cushion material and a protection member are shown. This cushion material is installed between a cover to which a support member for supporting the tuning fork type vibrator is fixed and a case around the cover, and has a function of absorbing vibration from the outside. Further, the protective members provided near the outer ends of both ends of the supporting member of the tuning fork type vibrator are
It has a function of preventing the tuning fork type vibrator from displacing more than necessary, that is, preventing the support member from being largely plastically deformed.

However, in the prior art example 1, when a vibration having a very large acceleration is applied, the cushion member cannot absorb the vibration, and the support member is plastically deformed, so that the central axis of the tuning fork vibrator is changed. The gyro characteristics will be greatly impaired because of deviation from the initial setting position. Moreover, the plastic deformation of the support member is further increased due to the impact,
The tuning fork vibrator may remain in contact with surrounding members. In such a case, the driving vibration stops, so that the function of the gyro sensor cannot be fulfilled at all.

On the other hand, the conventional example 2 solves the problems of the conventional example 1 and discloses a structure effective against an impact from the outside. Absorbs external shock between the work plate and the mounting plate of the support member that supports the tuning fork type vibrator, and between the circuit board with the work plate and the work cover and case attached to the work plate. A cushioning material is provided for this purpose. In the structure of the conventional example 2, a cushion material is provided between the outermost case, the circuit board housed inside the case, the shield cover of the circuit board, the work cover, the work plate, and the tuning fork type vibrator, and the external case is provided. Each cushioning material absorbs the impact from the.

However, in the conventional example 2, since a large amount of cushioning material is provided, there is a problem that the entire structure cannot be downsized. Further, when the tuning fork type vibrator is left in contact with the surrounding members, the function of the gyro sensor cannot be fulfilled at all, as in the case of the conventional example 1.

By the way, in a tuning fork type vibration gyro having a basic structure as shown in FIG. 16, when the center axis of rotation of the tuning fork type vibrator 1 and the support axis of the support arm 7 are completely aligned, For example, even if vibration in the Y direction is applied,
Since the upper and lower moments with the support axis as the boundary are equal, the tuning fork type vibrator 1 causes only translational vibration as shown in FIG. However, it is difficult to match both of these axes, and if vibrations in the Y direction are applied from the outside when both axes do not match, the vertical moment with the support axis as a boundary becomes unbalanced. As shown at 22, a rotational movement occurs. Therefore, there is a problem that an unnecessary rotational motion signal is detected even if the rotational motion is not applied to the tuning fork vibrator 1.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a tuning fork type vibration gyro which can reduce unnecessary signals generated when external vibration is applied. To do.

[0017]

A tuning fork type vibration gyro according to a first aspect of the present invention comprises a tuning fork type vibrator having two arms and a base, and a support substrate for supporting the base, and the tuning fork type vibration gyro is used as a driving side vibration. In a tuning fork type vibration gyro that performs in-plane vibration of a tuning fork type vibrator and torsional vibration in which the tuning fork type vibrator and a supporting substrate are integrated as detection side vibration, a resonance frequency of the driving side vibration and The absolute value of the difference between the detection-side vibration and the resonance frequency is equal to or more than the upper limit value of the required frequency characteristic.

In the tuning fork type vibration gyro according to the first aspect, the absolute value of the difference between the resonance frequency of the driving side vibration and the resonance frequency of the detecting side vibration is set to be equal to or higher than the upper limit value of the required frequency characteristic, and the external Reduces unwanted signals due to vibration.

A tuning fork type vibration gyro according to a second aspect of the present invention is characterized in that, in the first aspect, the absolute value of the difference is three times or more the upper limit value of the required frequency characteristic.

In the tuning fork type vibration gyro according to the second aspect, the absolute value of the difference is set to be three times or more the upper limit value of the required frequency characteristic, and the effect of reducing unnecessary signals due to vibration from the outside is great. .

The tuning fork type vibration gyro according to claim 3 is 2
Tuning fork type vibrator having two arms and a base, a circuit for exciting driving side vibration, a detection circuit for detecting detection side vibration generated when a rotational angular velocity is applied, and a detection signal of the detection circuit are converted into digital signals. A tuning fork type vibration gyro having a signal processing circuit for signal processing, the sampling frequency in the signal processing circuit being larger than twice the reciprocal of the integration time at the time of signal processing, in the resonance frequency of the driving side vibration and the detection side vibration. The absolute value of the difference from the resonance frequency is larger than the reciprocal of the integration time.

In the tuning fork type vibration gyro according to the third aspect of the present invention, the sampling frequency in the digital signal processing circuit of the detection system is made larger than twice the reciprocal of the integration time at the time of signal processing, and the resonance frequency of the driving side vibration and the detection side vibration. The absolute value of the difference from the resonance frequency of is larger than the reciprocal of the integration time, and unnecessary signals due to external vibration are reduced.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to the drawings showing the embodiments thereof. FIG. 1 is a configuration diagram of an example of a tuning fork type vibration gyro of the present invention. In the figure, reference numeral 1 denotes a tuning fork type vibrator, and the tuning fork type vibrator 1 has two arms 2 and 3 and a base 4 supporting them.
The arms 2, 3 and the base 4 are made of LiTaO ₃ , LiNb.
The piezoelectric single crystal such as O ₃ is integrally processed. The tuning fork type vibrator 1 is supported by connecting the base 4 of the tuning fork type vibrator 1 to the support substrate 6 provided on the stem 5.

The support arm 7 having a substantially U-shaped cross section
Is inserted into the slit of the support substrate 6 formed so as to include the center of rotation of the support substrate 6, and is flexibly attached to the support substrate 6 via the adhesive layer 8 made of a rubber-like elastic body. There is. Protrusions are provided at both ends of the support arm 7, and the protrusions are inserted into the holes formed in the stem 5. A cap 9 is provided to cover and protect these members. The cap 9 and the stem 5 form a case 10.

An annular (hollow rectangular parallelepiped) rocking limiting member 21 surrounds the base 4 and has a stem 5 on one surface thereof.
It is fixedly installed in. The swing limiting member 2
1 is provided at a position where almost no in-plane vibration occurs, that is, near the base 4 from the base of the arms 2 and 3 (the boundary between the arms 2 and 3 and the base 4, shown by the broken line A in FIG. 1). Since it is good, the swing limiting member 2 can be placed at any position on the base 4.
1 can be provided.

In such a tuning fork type vibration gyro, driving vibration (in-plane vibration) is excited as in the conventional example, and detection vibration (plane vertical vibration) occurs when a rotational angular velocity is applied, and the magnitude of this vibration is large. The angular velocity is obtained by detecting the output signal proportional to the height.

As described above, when external vibration or shock is applied to the conventional tuning fork type vibration gyro as shown in FIG. 16, the tuning fork vibrator 1 is responsive to the vibration or shock.
Sometimes oscillates, and the tuning fork type vibrator 1 collides with surrounding members. On the other hand, in the tuning fork type vibration gyroscope of the present invention as shown in FIG. 1, the swing limiting member 21 is provided around the base 4, and the tuning fork type vibrator 1 vibrates due to external vibration or shock. Even when the tuning fork type vibrator 1 is moved, the swing width of the tuning fork type vibrator 1 is limited by the existence of the swing limiting member 21, so that the tuning fork type vibrator 1 may collide with surrounding members such as the stem 5 and the cap 9. It can be prevented. As a result, the gyro characteristics are not impaired, and the driving vibration does not stop and the gyro function is not lost.

In the example shown in FIG. 1, the swing limiting member 21 is provided around the base 4 (tuning fork type vibrator 1), but such a swing is provided around the support substrate 6 or the adhesive layer 8. The motion limiting member 21 may be provided.

FIGS. 2 (a) and 2 (b) are configuration diagrams of characteristic portions of another example of the tuning fork type vibration gyro of the present invention. Figure 2
In each of the examples shown in (a) and (b), the swing limiting member 21 is formed directly on the base 4. In the example of FIG. 2 (a), the swing limiting member 21 is extended in both X and Y directions. The swing limiting member 21 is formed on the base 4, and in the example of FIG. 2B, the ring-shaped swing limiting member 21 is directly formed on the base 4.

With such a configuration, even when the tuning fork type vibrator 1 is largely swung due to vibration or impact from the outside, the swing limiting member 21 precedes the tuning fork type vibrator 1 so that the stem 5, the cap 9, etc. Because it contacts the surrounding members,
It is possible to prevent the tuning fork type vibrator 1 from colliding with surrounding members.

Although not shown in the drawing, FIG.
The swing limiting member 21 having the same shape as that of (b) may be formed on the support substrate 6.

FIGS. 3 (a) to 3 (c) are configuration diagrams of characteristic portions of still another example of the tuning fork type vibration gyro of the present invention. In this example, the swing limiting member 21 is integrally formed on the adhesive layer 8 that adheres the support substrate 6 and the support arm 7. Also in this example, when the tuning fork type vibrator 1 swings largely, the swing limiting member 21 comes into contact with the surrounding members first to prevent the tuning fork type vibrator 1 from colliding with the surrounding members.

In the example shown in FIGS. 3 (a) to 3 (c),
Although all the swing limiting members 21 are provided on the support substrate 6, the swing limiting members 21 in the upper and lower portions may be provided on the base 4. Further, the swing limiting member 21 may have an annular shape.

FIG. 4 is a block diagram of still another example of the tuning fork type vibration gyro of the present invention. 4, the same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In this example,
A circuit board 11 including a drive circuit that excites drive vibrations and a detection circuit that processes a detection signal is housed in a case 10 configured by the stem 5 and the cap 9. A circuit board 11 is present between the stem 5 and the tuning fork type vibrator 1, and the circuit board 11 is provided with terminal pins 12 penetrating the stem 5 for establishing electrical connection with an external circuit. There is.
Then, similarly to FIG. 1, a swing limiting member 21 is provided around the base 4. The lower surface of the swing limiting member 21 is fixed to the circuit board 11.

In such a structure, the swing width of the tuning fork type vibrator 1 is limited by the swing limiting member 21, and even if the tuning fork type oscillator 1 is largely swung, the tuning fork type oscillator 1 is not affected by the circuit board 11, the cap 9 or the like. It is possible to prevent collision with surrounding members.

FIG. 5 is a constitutional view of still another example of the tuning fork type vibration gyro of the present invention. 5, the same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In this example, a plurality of swing limiting members 21 are provided. In the example shown in FIG. 5, one swing limiting member 21 fixed to the stem 5 (or the circuit board 11) below the tuning fork type vibrator 1,
Two rocking limiting members 2 fixed to the inner wall surface of the cap 9.
1 and are provided.

In this way, the tuning fork type vibrator 1 and the case 10
And / or the tuning fork type vibrator 1 and the circuit board 11
When the rocking limiting member 21 is provided between and, the portion that comes into earliest contact with the surrounding members (tip portions of the arms 2 and 3)
So as not to contact the surrounding members (case 10, circuit board 11), that is, the clearance between the arms 2, 3 and / or the arms 2, 3, circuit board 11
It is necessary to design the position and shape of the swing limiting member 21 so that the clearance between them becomes a predetermined value or more.

In FIG. 6, when the swing limiting member 21 is provided below the tuning fork type vibrator 1, the tips of the arms 2 and 3 are defined so as not to come into contact with the stem 5 (or the circuit board 11). It is a schematic diagram which shows an example. The distance between the tuning fork type oscillator 1 and the stem 5 (or the circuit board 11) is H, and the distance between the swing center of the tuning fork type oscillator 1 and the support substrate 6 and the tips of the arms 2 and 3 is L. When the tuning fork type vibrator 1 swings, the distance between the position at which the tuning fork type vibrator 1 or the support substrate 6 contacts the swing limiting member 21 and the stem 5 (or the circuit board 11) is H '. The distance between the position where the tuning fork type vibrator 1 or the support substrate 6 contacts the swing limiting member 21 and the swing center of the tuning fork type oscillator 1 and the support substrate 6 when the oscillator 1 swings is L '. In this case, the position and shape of the swing limiting member 21 are designed so that the following expressions (A) and (B) are simultaneously satisfied. H = L × sin θ> 0 (A) tan θ = (H−H ′) / L ′ (B)

If the position and shape of the swing limiting member 21 are designed so as to satisfy the above expressions (A) and (B),
The tip portions of the arms 2 and 3 never contact the stem 5 (or the circuit board 11). Therefore, when the tip portions of the arms 2 and 3 do not contact the stem 5 (or the circuit board 11), the minimum value of the height of the swing limiting member 21 is (A),
It can be defined by the formula (B). Therefore, since the rocking | swiveling limiting member 21 of the minimum height can be provided, the raw material cost and weight of the rocking | swiveling limiting member 21 can be reduced.

In the above example, the design criteria of the position and shape of the swing limiting member 21 when the swing limiting member 21 is provided below the tuning fork type vibrator 1 are shown.
Even when the swing limiting member 21 is provided on the inner wall of the (cap 9), the position and shape of the swing limiting member 21 can be designed in the same manner.

Here, the material used for the swing limiting member 21 and the hardness thereof will be described. As the material of the rocking limiting member 21, resin such as epoxy and urethane, silicon,
An elastic body of rubber such as butyl or a foam material thereof can be used. With such a material, a large amount of the rocking restricting member 21 having a complicated shape can be easily manufactured in advance by using a jig. Therefore, even when the swing limiting member 21 is provided, the tuning fork type vibration gyro can be easily assembled, which can contribute to reduction in the number of steps and cost.

In the configuration shown in FIG. 6, the tuning fork type vibrator 1
An experiment was conducted to examine whether or not the arms 2 and 3 were broken by applying a constant impact of 1500 (G) from the outside in the Y direction, which is the most apt to swing, and changing the hardness of the swing limiting member 21. The result is shown in FIG. 7. In an example (comparative example) in which the swing limiting member 21 is not provided, the arms 2 and 3 collide with surrounding members and are broken. On the other hand, the hardness is 102 (JIS
In A), although the arms 2 and 3 do not collide with the surrounding members, the swing limiting member 21 itself is hard and less elastic, so the arms 2 and 3 are broken by the impact of contact with the swing limiting member 21. It was Therefore, when the swing limiting member 21 is formed of an elastic body having a hardness of 100 (JIS A) or less, it is understood that the arms 2 and 3 are not broken and it is effective in preventing the tuning fork type vibrator 1 from being broken. A closed container containing a material having a low hardness (for example, 0 (JIS A)) can be used as the swing limiting member 21.

In the structure in which the swing limiting member 21 is provided as described above, the tuning fork type vibrator 1 inevitably swings with respect to external vibration or impact, and the supporting portion of the tuning fork type vibrator 1 is an elastic body. It is especially effective in some tuning fork type vibration gyros. The tuning fork type vibration gyro of the present invention does not absorb or absorb external vibration or impact as in the conventional case, but has a configuration in which the swing limit member 21 limits the swing width of the tuning fork type vibrator 1. However, it differs from the conventional examples 1 and 2 in dealing with external vibration or shock. Further, in the present invention, the work cover, work plate, shield cover, cushion material, etc. as shown in the conventional examples 1 and 2 are not required, and the size can be greatly reduced.

Hereinafter, a tuning fork type vibration gyro of the present invention will be described which is capable of reducing unnecessary signals generated when vibration is applied from the outside.

FIG. 8 is a diagram showing the relationship between the drive signal and the detection signal in the tuning fork type vibration gyro. When the rotational motion is applied, the gyro detection signal is a signal having a drive frequency as shown in FIG. An AM modulated wave is obtained by adding a detection wave having a period t to the.

FIG. 9 is a graph showing the relationship between the rotation frequency applied to the tuning fork type vibration gyro and the response output. In the graph of FIG. 9, the absolute value of the difference Δf between the resonance frequency of the driving side vibration and the resonance frequency of the detecting side vibration is three kinds of values (4
0 Hz, 80 Hz, 120 Hz). As shown in FIG. 9, the frequency characteristic of the tuning fork vibrator 1 itself is determined by | Δf |, and its response output has a peak when a rotation of a frequency near | Δf | is applied. Therefore, if | Δf | is made smaller than the upper limit value Fmax of the required frequency characteristic of the tuning fork type vibration gyro, the frequency response characteristic including the peak portion is obtained, and the vibration from the outside also has a large amplitude. Become. Therefore,
In the present invention, this | Δf | is defined as the upper limit value F of the required frequency characteristic.
A flat frequency response characteristic is obtained at Fmax or lower by setting the value to be equal to or higher than max and by using an LPF (low-pass filter) of the circuit together.

FIG. 10 is a block diagram of an analog detection circuit using such an LPF. This analog detection circuit has a differential amplifier 31 that receives a detection voltage signal from two detection electrodes provided on the arms 2 and 3 and outputs a signal proportional to the difference between the two inputs, and a differential amplifier 31. A synchronous detector 32 for synchronously detecting an output signal from the rectifier, an oscillator 33 for oscillating a reference clock as a synchronous signal and outputting the reference clock to the synchronous detector 32, and a predetermined filtering characteristic (cutoff frequency Fc)
And a DC amplifier 35 for amplifying the output of the LPF 34.

FIG. 11 is a diagram showing the synthesis of frequency response characteristics in such an analog detection circuit.
FIG. 11A is an angular velocity frequency characteristic of the tuning fork type vibrator 1, FIG.
11B shows an example of frequency characteristics of the LPF 34, and FIG. 11C shows an example of frequency response characteristics of an actual tuning-fork type vibration gyro. When | Δf | is slightly larger than Fmax in accordance with Fmax and the cutoff frequency Fc of the LPF 34 is slightly larger than Fmax, the actual frequency response characteristic of the tuning fork type vibration gyro is 1 own frequency characteristics (Fig. 11 (a)) and LP
The frequency characteristic of F34 (FIG. 11 (b)) is combined (FIG. 11 (c)), and has a large peak at a frequency equal to or higher than Fmax. Then, the vibration from the outside also has a large amplitude at a frequency substantially equal to this peak portion.

Therefore, in order to reduce the unnecessary signal as noise generated by the vibration from the outside, | Δf |
Must be sufficiently larger than x. Since it is considered that Fc conforms to Fmax, both values may be substantially equal. Therefore, by making | Δf | sufficiently larger than Fc, the above-mentioned unnecessary signal can be reduced.

FIG. 12 is a diagram showing a detection signal (converted to a voltage) in the case where an external vibration is experimentally applied to the tuning fork type vibration gyro having changed | Δf | and Fc.
(A), (b), (c) show | Δf | = 120 Hz, respectively
At Fc = 60 Hz, | Δf | = 200 Hz, Fc = 60
Shown are the experimental results when Fc = 22 Hz at Hz, | Δf | = 200 Hz. In the case of | Δf | = 2 × Fc (see FIG. 1)
It was confirmed that unnecessary signals were significantly reduced in the case of | Δf |> 3 × Fc (FIG. 12B), as compared with 2 (a)). Furthermore, when | Δf |> 9 × Fc is satisfied (FIG. 12C), it has been confirmed that the unnecessary signal is dramatically reduced.

Next, a tuning fork type vibration gyro having a digital signal processing circuit for converting an analog detection signal into a digital signal and processing the digital signal will be described.

FIG. 13 is a block diagram of such a digital signal processing circuit. This digital signal processing circuit converts an input analog detection signal into a digital signal A.
It has an / D converter 41 and an integrator 42 that integrates the output of the A / D converter 41 over a predetermined time.

As described above (see FIG. 8), the analog detection signal of the tuning fork type vibration gyro has a mode in which the detection wave of the cycle t due to the rotational movement is added to the drive signal. Therefore, in order to effectively remove the unnecessary rotation angular velocity signal, the digital signal processing circuit of the detection system requires at least a half period (t / 2) of the detection wave or more, and the integration It is necessary to take a sampling frequency fs that is at least the reciprocal of time (2 / t). Here, the upper limit value of the detectable angular frequency (request frequency characteristic), so-called 1 /
The maximum value of t is less than or equal to the absolute value of Δf described above. Therefore, by satisfying the conditions of fs> t / 2 and | Δf |> 1 / t at the same time, it becomes possible to effectively remove unnecessary signals.

FIGS. 14 and 15 show detection signals (angular velocity) when experimentally external vibration is applied to the tuning fork type vibration gyro of the present invention example satisfying the above two conditions and the comparative example not satisfying the above two conditions. FIG. 14 and FIG. 15 show the experimental results of the present invention example and the comparative example, respectively. In both examples, vibration was applied in the Y direction at 140 Hz and 1 G, and f
s = 1 kHz, t = 1 sec. , Δf = 120 Hz. In the present invention example, the amplitude of the unnecessary signal is 1 compared with the comparative example.
It became / 5, and it was confirmed that the method of the present invention is effective for reducing unnecessary signals generated when vibration is applied from the outside.

[0055]

As described above, in the tuning fork type vibration gyroscope of the present invention, the absolute value of the difference between the resonance frequency of the driving side vibration and the resonance frequency of the detecting side vibration is larger than the upper limit value of the required frequency characteristic, or , Is larger than the reciprocal of the integration time,
Unwanted signals due to external vibration can be significantly reduced, and vibration resistance characteristics can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an example of a tuning fork type vibration gyro of the present invention.

FIG. 2 is a configuration diagram of a characteristic portion of another example of the tuning fork type vibration gyro of the present invention.

FIG. 3 is a configuration diagram of a characteristic portion of still another example of the tuning fork type vibration gyro of the present invention.

FIG. 4 is a configuration diagram of still another example of the tuning fork type vibration gyro of the present invention.

FIG. 5 is a configuration diagram of still another example of the tuning fork type vibration gyro of the present invention.

FIG. 6 is an explanatory diagram for defining the position and shape of a swing limiting member.

FIG. 7 is a chart showing an experimental result regarding hardness of a swing limiting member.

FIG. 8 is a diagram showing a relationship between a drive signal and a detection signal in the tuning fork type vibration gyro.

FIG. 9 is a graph showing a relationship between a rotation frequency and a response output in the tuning fork type vibration gyro.

FIG. 10 is a configuration diagram of an analog detection circuit of a tuning fork type vibration gyro.

FIG. 11 is a diagram showing composition of frequency response characteristics in an analog detection circuit.

FIG. 12 is a diagram showing an experimental result of a detection signal (converted into a voltage) when a tuning fork type vibration gyro is externally vibrated.

FIG. 13 is a configuration diagram of a digital signal processing circuit of a tuning fork type vibration gyro.

FIG. 14 is a diagram showing an experimental result of a detection signal (converted into angular velocity) when vibration is externally applied to a tuning fork type vibration gyro (example of the present invention).

FIG. 15 is a diagram showing an experimental result of a detection signal (converted into angular velocity) when a vibration is applied from the outside to a tuning fork type vibration gyro (conventional example).

FIG. 16 is a configuration diagram of a conventional tuning fork type vibration gyro.

FIG. 17 is a diagram showing a vibrating state of a tuning fork type vibrator.

FIG. 18 is a diagram showing a swinging motion of a tuning fork type oscillator due to external vibration or impact.

FIG. 19 is a diagram showing a state in which the tip of the arm contacts the case.

FIG. 20 is a diagram showing a state in which the tip of the arm contacts the circuit board.

FIG. 21 is a diagram showing translational movement of a tuning fork type oscillator due to external vibration.

FIG. 22 is a diagram showing a rotational movement of a tuning fork type oscillator due to external vibration.

[Explanation of symbols]

1 Tuning fork vibrator A few arms 4 base 5 stems 6 Support substrate 7 Support arm 8 Adhesive layer 9 cap 10 cases 11 circuit board 21 Swing limiting member

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Ishikawa             4-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa             No. 1 within Fujitsu Limited (72) Inventor Masaki Taniuchi             4-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa             No. 1 within Fujitsu Limited (72) Inventor Yoshio Sato             4-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa             No. 1 within Fujitsu Limited (72) Inventor Kikuchi Koji             3-18-3 Shin-Yokohama, Kohoku Ward, Yokohama City, Kanagawa Prefecture             Issue inside Fujitsu Towa Electron Limited (72) Inventor Yoshitaka Takahashi             3-18-3 Shin-Yokohama, Kohoku Ward, Yokohama City, Kanagawa Prefecture             Issue inside Fujitsu Towa Electron Limited F term (reference) 2F105 AA01 BB03 BB12 CC01 CD02                       CD06 CD13

Claims (3)

[Claims] 1. A tuning fork type vibrator having two arms and a base, and a support substrate for supporting the base, wherein an in-plane vibration of the tuning fork type vibrator as driving side vibration and a detection side vibration are provided. In a tuning fork type vibration gyro that performs torsional vibration in which the tuning fork type vibrator and a supporting substrate are integrated, the absolute value of the difference between the resonance frequency of the drive side vibration and the resonance frequency of the detection side vibration is the required frequency. A tuning fork type vibrating gyro, which is characterized in that the characteristic is not less than the upper limit. 2. The tuning fork type vibration gyro according to claim 1, wherein the absolute value of the difference is three times or more the upper limit value of the required frequency characteristic. 3. A tuning fork type oscillator having two arms and a base, a circuit for exciting a driving side vibration, a detection circuit for detecting a detection side vibration generated when a rotational angular velocity is applied, and a detection of the detection circuit. A tuning fork type vibration gyro having a signal processing circuit for converting a signal into a digital signal and processing the signal, wherein the sampling frequency in the signal processing circuit is greater than twice the reciprocal of the integration time during signal processing. A tuning fork type vibration gyro, wherein the absolute value of the difference between the resonance frequency of the detection side vibration and the resonance frequency is larger than the reciprocal of the integration time.