JP2004317380A - Biaxial detection type doublet tuning fork oscillation gyro-sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precise biaxial detection type angular velocity sensor excellent in vibration resistance and impact resistance. <P>SOLUTION: Two arm parts, and two doublet tuning fork support parts for supporting respectively both ends of the arm parts are integrally constituted, and a driving electrode is formed on surfaces of the arm parts, in this biaxial detection type doublet tuning fork oscillation gyro-sensor. The gyro-sensor is provided with two support fixing parts, two detecting parts for connecting the respective support fixing parts integrally to the doublet tuning fork support parts, the first detecting electrode formed in the detecting parts, and the second detecting electrode formed on the surface of the arm parts. The first detection signal corresponding to a rotational angular velocity of rotation with respect to an axis perpendicular to a plane including the two arm parts is output from the first detecting electrode, and the second detection signal corresponding to a rotational angular velocity of rotation with respect to an axis parallel to the arm parts is output from the second detecting electrode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a double tone type vibration gyro sensor using Coriolis force.
[0002]
[Prior art]
As a sensor for detecting the rotation of an object, a vibrating gyro sensor using a Coriolis force is widely used. In particular, since a pitch type vibration gyro sensor called a horizontal horizontal type can be made thinner, its application range is wide, such as for camera shake prevention and for a car navigation system.
2. Description of the Related Art In recent years, horizontal and horizontal pitch-type vibration gyro sensors have been studied for use in vehicle travel control applications. The running control of a vehicle is a vital factor that determines the safety of the entire vehicle, and a vibrating gyro sensor for this application is required to have particularly high vibration and shock resistance and high accuracy.
[0003]
2. Description of the Related Art A horizontal and horizontal pitch-type vibrating gyro sensor for thinning has been proposed in the IEICE Technical Report US97-56, 1997-09. However, since this type has a single-point support structure in which the root of the pitch is fixed and the tip of the pitch is free, there is a problem that the vibration / shock resistance is weak.
In view of this, the inventor of the present application has devised a horizontal and horizontal double-tone vibrating gyro sensor which is excellent in vibration / shock resistance, is highly accurate, and can respond to thinning and miniaturization, and discloses it in Japanese Patent Application No. 2002-264872. No. has been filed.
[0004]
FIG. 9A is an external view of a conventional double tone vibration gyro sensor disclosed in Japanese Patent Application No. 2002-264872.
In FIG. 9A, a conventional double-tone vibrating gyrosensor processes a Z-plate quartz crystal slice cut so that the normal direction of the main surface of the substrate is the crystal Z-axis direction, and forms the double-tone shape. A drive unit 2 having a predetermined electrode formed on a surface thereof, the drive unit 2 having a pair of strip-shaped arm portions 1a and 1b and a drive electrode (not shown) formed on the surface of the arm portions 1a and 1b; It has a double tone support part 3a, 3b supporting both ends of the drive unit 2, and a detection electrode (not shown), and detects the vibration of the arm parts 1a, 1b via the double tone support part 3a, 3b. It includes detection units 4a and 4b, and support fixing units 5a and 5b that support one end of the detection units 4a and 4b and have a pair of extraction electrodes (not shown) connected to the detection electrodes (not shown). ing.
Further, the support fixing portions 5a and 5b are used by being fixed to a mounting surface (horizontal surface) of a sensor package or the like with an adhesive or the like, but are not illustrated here.
[0005]
The conventional double tone vibration gyro sensor shown in FIG. 9 operates as follows.
First, consider the non-rotating state. When a drive signal is applied to a drive electrode (not shown) of the drive unit 2, as shown in FIG. 2B, the arm portions 1 a and 1 b are subjected to bending vibration (drive mode called an in-plane symmetric bending primary vibration mode). ) Occurs. At this time, the arms 1a and 1b vibrate symmetrically with each other in the figure.
Therefore, an angular velocity (rotation) about the crystal Z-axis is given to the double tone vibrating gyro sensor vibrating in this drive mode. Then, a Coriolis force acts on one of the arms 1a and 1b in the Y direction (upward in the figure) and the other in the Y direction (downward in the figure). As a result, the arm portions 1a and 1b generate a bending vibration (detection mode) called an in-plane asymmetric bending secondary mode as shown in FIG.
[0006]
At this time, a moment is generated in each of the double tone support portions 3a and 3b, and accordingly, the detection portions 4a and 4b vibrate in the X direction correspondingly. As a result, detection voltages whose polarities are inverted from each other are generated at the detection electrodes provided on the detection units 4a and 4b in accordance with the vibration.
Therefore, the detection units 4a and 4b hardly generate vibration components in the X direction during non-rotation (during the drive mode), and generate X-direction vibration components only during rotation (during the detection mode). If the differential component between the two detection voltages output from 4a and 4b is used as a detection signal, a voltage proportional to the rotational angular velocity can be obtained. When the rotation direction is reversed, the polarity of the detection signal is reversed.
[0007]
[Problems to be solved by the invention]
However, the conventional double tone type vibration gyro sensor has the following problems.
That is, the conventional double tone type vibration gyro sensor has a structure capable of detecting only rotation about the Z axis. The general vibration gyro sensor is not limited to the twin tone type, but has a single rotation detection axis, and has a structure in which rotation about an axis orthogonal to the detection axis cannot be detected.
[0008]
For this reason, for the purpose of mounting on a vehicle, it is necessary to simultaneously detect the rotational angular velocities with respect to two orthogonal axes or three axes. Therefore, at least two or three vibration gyro sensors are mounted, and the detection axis of each vibration gyro sensor is detected. Are arranged so as to be orthogonal to each other.
However, mounting a plurality of vibration gyro sensors occupies a space inside the vehicle, which makes it difficult to reduce the size. Furthermore, since a plurality of vibration gyro sensors are required, the cost naturally increases.
[0009]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is a horizontal and horizontal type two-axis detection sound type vibrating gyroscope which is excellent in vibration and shock resistance, and which can correspond to high accuracy and downsizing. It is intended to provide a sensor.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned object, the invention according to claim 1 according to the present invention comprises integrally forming two arm portions and two dipole support portions respectively supporting both ends of the arm portion. A double tone vibrating gyro sensor having a driving electrode formed on a surface of the arm part, wherein two support fixing parts, and each of the support fixing parts and each of the double tone supporting parts are integrally formed. , A first detection electrode formed on the detection unit, and a second detection electrode formed on the surface of the arm, and are orthogonal to a plane including the two arms. A first detection signal corresponding to a rotation angular velocity of rotation with respect to an axis is output from the first detection electrode, and a second detection signal corresponding to a rotation angular velocity of rotation with respect to an axis parallel to the arm portion is output from the second detection signal. Output from the detection electrode It is. Therefore, with this configuration, it is possible to simultaneously detect rotations in two orthogonal axis directions.
[0011]
According to a second aspect of the present invention, in the first aspect, the drive electrodes are formed on the surface of either two of the arm portions or any one of the arm portions.
According to a third aspect of the present invention, in the first or second aspect, the second detection electrode is formed on a surface of either one of or two of the arm portions. Therefore, the configuration of claim 2 or 3 has an effect of improving the degree of freedom of electrode arrangement in forming the drive electrode and the second detection electrode.
[0012]
According to a fourth aspect of the present invention, in the first, second, or third aspect, a normal direction of a plane including two arms as a material of the double tone type vibration gyro sensor is set to be the same as that of the first aspect. A crystal cut so as to be the Z axis of the crystal axis is used.
According to a fifth aspect of the present invention, in the first, second, third, or fourth aspect, the detection unit is formed in a strip shape.
Therefore, there is an effect that the configuration of claim 4 or claim 5 achieves high accuracy.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
FIGS. 1A and 1B are external views of a two-axis detection type double tone vibrating gyroscope according to the present invention, wherein FIG. 1A is a top view, and FIG. 1B is a bottom view (see through from the top). (State) and (c) show side views. The plane parallel to the paper surface of FIG. 1 is a horizontal plane (mounting surface), and the side view illustrates a state where the mounting surface is fixed to the mounting base with an adhesive or the like.
[0014]
The double-tone vibrating gyro sensor shown in FIG. 1 is formed by processing a Z-plate quartz thin piece cut so that the normal direction of the main surface of the substrate is the crystal Z-axis direction into a double-tone shape, and forming a predetermined shape on the surface thereof. A drive detection unit 6 having electrodes formed thereon, the drive detection unit 6 having a pair of strip-shaped arm portions 1a and 1b, and a drive electrode described later and a second detection electrode described later formed on the surface of the arm portions 1a and 1b. And a pair of first detection electrodes 7a for supporting both ends of the drive detection unit 6 and the pair of first detection electrodes 7a. A detection unit 4a for detecting vibration of the arm, a detection unit 4b having a pair of first detection electrodes 7b, and detecting the vibration of the arm units 1a and 1b via the double tone support unit 3b; It supports one end of the portion 4a and contacts the first detection electrode 7a. A support fixed portion 5a having a pair of lead-out electrodes 8a to, and a support fixing portion 5b having a pair of lead-out electrode 8b is connected to the detection electrode 7b to support the one end of the detecting section 4b. Here, the electrode patterns of the first detection electrodes 7a and 7b and the extraction electrodes 8a and 8b shown in FIG. 1 are formed with the same electrode pattern on the back surface, and are connected via the pattern on the side surface.
[0015]
Further, in the drive detection section 6 of FIG. 1, a drive electrode and a second detection electrode are formed on the upper surface, the bottom surface, and the side surface. FIG. 2 shows an arrangement example of these electrode patterns.
FIG. 2 illustrates respective cross sections of an AA ′ portion, a BB ′ portion, and a CC ′ portion of FIG. In FIG. 2, D + and D− represent drive electrodes 9a and 9b, Sy1 + and Sy1- represent a pair of second detection electrodes 10a formed on the surface of the left arm 1a, and Sy2 + and Sy2- represent right arm. 5 shows a pair of second detection electrodes 10b formed on the surface of the portion 1b. The second detection electrode 10a and the second detection electrode 10b are formed as independent electrodes.
The drive electrodes 9a (D +) and 9b (D-) are applied with drive signals of opposite polarities. G is a ground electrode 11 and M is a monitor electrode 12.
[0016]
The drive electrodes 9a, 9b, the second detection electrode 10a, the second detection electrode 10b, the ground electrode 11, and the monitor electrode 12 are drawn out to the double tone support portions 3a, 3b in FIG. Are formed lead electrodes 13a (D +), 13b (D-), 13c (Sy1 +, Sy1-), 13d (Sy2 +, Sy2-), 13e (G), and 13f (M).
[0017]
The double tone vibration gyro sensor shown in FIG. 1 operates as follows.
First, consider the non-rotating state. When a drive signal having an inverted polarity is applied to each of the extraction electrodes 13a (D +) and 13b (D−), the drive signal is applied to the drive electrodes 9a (D +) and 9b (D−) formed on the arms 1a and 1b, respectively. Accordingly, a bending vibration (drive mode) called an in-plane symmetric bending primary vibration mode as shown in FIG. 3A is generated in the arm portions 1a and 1b. At this time, the arm portions 1a and 1b vibrate symmetrically to each other (X direction).
[0018]
However, the drive electrodes 9a and 9b are arranged so that the support portions at both ends of the arm portions 1a and 1b move in the opposite direction to the central portion of the arm portions 1a and 1b so as not to swing left and right as much as possible. This is because when the distortion caused by the bending vibration at the center of the arms 1a and 1b in the non-rotational state is applied to the connecting portion between the arms 1a and 1b and the double tone supporters 3a and 3b, this is transmitted to the detectors 4a and 4b. Because it will be transmitted. Therefore, in bending vibration (drive mode) during non-rotation, the left and right movements of both ends of the arm portions 1a and 1b are suppressed so that the connection portion does not move as much as possible.
[0019]
Next, only the rotation about the crystal Z-axis, that is, the axis orthogonal to the plane including the center of the two arms 1a and 1b, is given to the double-tone vibrating gyro sensor vibrating in this drive mode. . For example, when clockwise rotation occurs in FIG. 1A, when the arm portions 1a and 1b vibrate in a direction away from each other, a downward Coriolis force acts on the left arm 1a in FIG. An upward Coriolis force acts.
When the arms 1a and 1b vibrate in a direction approaching each other, an upward Coriolis force acts on the left arm 1a in the figure, and a downward Coriolis force acts on the right arm 1b. Accordingly, Coriolis forces act on the arms 1a and 1b in opposite directions so as to slide in the vertical direction (y direction) in the figure, and thus the arms 1a and 1b have in-plane asymmetry as shown in FIG. A bending vibration (first bending vibration) called a bending secondary mode occurs. At this time, a moment is generated in each of the double tone support portions 3a and 3b due to the first bending vibration, and accordingly, the detection portions 4a and 4b vibrate in the X direction correspondingly.
[0020]
Accordingly, in response to the vibration of the detection units 4a and 4b in the X direction, the first detection electrodes 7a and 7b provided in the detection units 4a and 4b respectively have two detection voltages (first Detection signal) is generated. Then, this is output via the extraction electrodes 8a and 8b formed on the support fixing portions 5a and 5b.
Although a voltage proportional to the rotational angular velocity around the Z axis is obtained as the first detection signal, when the rotational direction around the Z axis is reversed, the direction of the Coriolis force acting on each of the arms 1a and 1b is reversed. Accordingly, the polarity of the first detection signal is also inverted, so that if the phase difference of the first detection signal with respect to the drive signal is measured, the rotation direction with respect to the Z axis can be detected.
[0021]
On the other hand, consider a case where only the rotation about the crystal Y axis, that is, the longitudinal direction of the two arm portions 1a and 1b is given to the double tone type vibration gyro sensor. For example, in FIG. 1, when the Y-axis rotates clockwise, when the arm portions 1a and 1b are vibrating in directions away from each other, the left arm 1a is directed upward in the Z direction, that is, in a direction penetrating vertically upward in FIG. Coriolis force acts, and Coriolis force acts on the right arm portion 1b downward in the Z direction.
When the arms 1a and 1b are vibrating in directions approaching each other, a downward Coriolis force acts on the left arm 1a in the Z direction, and an upward Coriolis force acts on the right arm 1b in the Z direction. As a result, bending vibrations (second bending vibrations) in the Z-axis direction as shown in FIG. 3C are generated in the arm portions 1a and 1b due to the opposite Coriolis forces.
At this time, the second detection electrodes 10a (Sy1 +, Sy1-) and the second detection electrodes 10b (Sy2 +, Sy2-) formed on the arms 1a, 1b of the drive detection unit 6 are respectively connected to the second detection electrodes 10a (Sy2 +, Sy2-). A second detection signal synchronized with the drive signal is generated according to the bending vibration. This is transmitted to the extraction electrodes 13c and 13d formed on the double tone support portion 3a, from which a second detection signal for rotation about the Y axis is output.
[0023]
Here, when rotation about the Z-axis and rotation about the Y-axis are simultaneously applied to the double tone vibration gyro sensor, the arm portions 1a and 1b are in a state where the first bending vibration and the second bending vibration are combined. become. In addition, stopping one rotation has almost no effect on the Coriolis force with respect to the other rotation, and the first and second bending vibrations may be considered to be independent of each other. The detection signals can be handled as signals independent of each other.
[0024]
That is, the arms 1a and 1b hardly vibrate in the Z direction during non-rotation (during the drive mode) or rotation around the Z-axis (during the Z-axis detection mode), and rotate around the Y-axis (Y-axis detection). Vibrates in the Z direction only when (mode) is applied. Therefore, if the differential component of the second detection signal output from the extraction electrodes 13c and 13d is used as a detection signal, a voltage proportional to the rotational angular velocity about the Y axis can be obtained.
Here, when the rotation direction around the Y axis is reversed, the direction of the Coriolis force acting on each of the arm portions 1a and 1b is reversed, and accordingly the polarity of the second detection signal is also reversed. If the phase difference between the detection signals is measured, the rotation direction around the Y axis can be detected.
[0025]
The second detection signals are output from the arm units 1a and 1b in pairs, but only one of the outputs may be used.
In the present embodiment, since the electrodes are formed symmetrically on the left and right arms 1a and 1b, two pairs of second detection signals can be output independently.
[0026]
As described above, the two-axis detection type double tone vibration gyro sensor according to the present invention includes two orthogonal rotation detection axes, and separately detects rotation around the Y axis and rotation around the Z axis. Since the first and second detection signals for each rotation can be output simultaneously and independently, it is not necessary to mount a plurality of sensors on a vehicle or the like, and miniaturization and space saving can be achieved.
[0027]
As described above, in the two-axis detection type double tone vibration gyro sensor according to the present invention, the drive electrode and the second detection electrode are described as being formed on both surfaces of the arm portions 1a and 1b. However, the present invention is not limited to this, and the drive electrode and the second detection electrode may be formed on the surface of one of the arms.
4 to 8 show another example of the arrangement of the drive electrodes and the second detection electrodes formed on the arms 1a and 1b. Hereinafter, these arrangement examples will be briefly described.
FIG. 4 shows an example in which the drive electrodes and the second detection electrodes are arranged on the left and right arms. Although the electrode arrangement is different from that of FIG. 2, a drive electrode, a second detection electrode, a ground electrode, and a monitor electrode are arranged on any of the upper surface, the side surface, and the bottom surface of the arm portion.
[0028]
FIGS. 5 and 6 show examples in which the drive electrodes are arranged only on the left arm and the second detection electrodes are arranged only on the right arm. In this arrangement example, since the drive signal is applied only to the left arm, the bending vibration is excited in the left arm. At the same time, the bending is also caused in the left arm by the reaction of the bending vibration excited in the left arm. Vibration occurs and the left and right arms move in opposite directions synchronously. Therefore, a detection signal can be output from the second detection electrode of the left arm portion in the same manner as in the electrode arrangement examples of FIGS.
Further, as can be seen from the arrangement examples of FIGS. 5 and 6, the drive electrode and the second detection electrode may be provided in at least one of the arm portions.
[0029]
FIGS. 7 and 8 show examples in which both the drive electrode and the second detection electrode are arranged on the left and right arm portions. Only the arrangement of the second detection electrode is vertically asymmetrical. Detection is possible even with the arrangement. The arrangement of the extraction electrodes formed on the double tone support portions 3a and 3b can be appropriately changed in accordance with the electrode arrangement examples of FIGS. 4 to 8 described above, and the extraction electrode 13a illustrated in FIG. , 13b, 13c, 13d, 13e, and 13f need not be exactly the same as the arrangement example. Therefore, in the present invention, the degree of freedom of electrode arrangement is relatively high.
[0030]
Further, in the two-axis detection type double tone type vibration gyro sensor according to the present invention, a material obtained by processing a Z-plate quartz crystal slice cut so that the normal direction of the main surface of the substrate is the crystal Z-axis direction is used. However, the present invention is not limited to this, and a piezoelectric ceramic may be used as a material, or another piezoelectric element may be used as a material.
[0031]
【The invention's effect】
As described above, the present invention provides an angular velocity sensor utilizing a Coriolis force, a horizontal and horizontal type double-tone vibration gyro sensor, two orthogonal rotation detection axes, and two rotation detection axes corresponding to the rotation detection axes. Since it is configured to output two detection signals simultaneously and independently, it is excellent in vibration resistance and shock resistance required for use in automobiles, etc., and has high precision that enables space saving and miniaturization. This is very effective in providing an angular velocity sensor.
[Brief description of the drawings]
FIG. 1 is an external view of a two-axis detection type double tone vibration gyro sensor according to the present invention.
FIG. 2 is a first electrode arrangement example of a two-axis detection type double tone vibration gyroscope according to the present invention.
FIG. 3 is a diagram showing a state of bending vibration of a two-axis detection type double tone vibration gyro sensor according to the present invention.
FIG. 4 is a second electrode arrangement example of the two-axis detection type double tone vibration gyro sensor according to the present invention.
FIG. 5 is a third electrode arrangement example of the two-axis detection type double tone vibration gyro sensor according to the present invention.
FIG. 6 is a fourth electrode arrangement example of the two-axis detection type double tone vibration gyro sensor according to the present invention.
FIG. 7 is a fifth electrode arrangement example of the two-axis detection type double tone vibration gyro sensor according to the present invention.
FIG. 8 shows a sixth electrode arrangement example of the two-axis detection type double tone vibration gyro sensor according to the present invention.
FIG. 9 is an external view of a conventional double tone vibration gyro sensor.
[Explanation of symbols]
1a, 1b Arm 2 Drive 3a, 3b Dual tone support 4a, 4b Detection 5a, 5b Support fixing 6 Drive detection 7a, 7b First detection electrodes 8a, 8b Leader electrodes 9a, 9b Drive electrodes 10a, 10b Second detection electrode 11 Ground electrode 12 Monitor electrodes 13a, 13b, 13c, 13d, 13e, 13f Leader electrodes

Claims (5)

A twin tone type vibration gyro sensor in which two arm portions and two double tone support portions respectively supporting both ends of the arm portion are integrally formed, and a driving electrode is formed on a surface of the arm portion. And
Two support fixing portions, two detection portions that respectively integrally connect the respective support fixing portions and the respective dichotomous support portions, a first detection electrode formed on the detection portion, A second detection electrode formed on the surface of the arm, and outputting a first detection signal from the first detection electrode corresponding to a rotational angular velocity of rotation with respect to an axis orthogonal to a plane including the two arms. Along with
A two-axis detection type double tone vibration gyro sensor, wherein a second detection signal corresponding to a rotational angular velocity of rotation about an axis parallel to the arm portion is output from the second detection electrode. 2. The two-axis detection type double tone vibration gyro sensor according to claim 1, wherein the drive electrodes are formed on both or one of the arms. The two-axis detection type double tone vibration gyro sensor according to claim 1 or 2, wherein the second detection electrode is formed on both or one of the surfaces of the arm portion. . 2. A crystal material cut so that a normal direction of a plane including two arm portions is a Z axis of a crystal axis, as a material of the double tone type vibration gyro sensor. The two-axis detection type double tone type vibration gyro sensor according to claim 2 or 3. 5. The two-axis detection type double tone vibration gyro sensor according to claim 1, wherein the detection unit is formed in a strip shape.

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