JPH10288527A - Angular velocity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To abate the temperature drift of a sensor, in this angular velocity sensor detecting an angular velocity with a tuning fork-form vibrator consisting of a piezoelectric body. SOLUTION: A vibrator is formed into a nearly U-shaped tuning-fork form having a pair of arm parts 4, 5 and a connecting part 6 connecting one end of these arm parts 4 and 5. This vibrator is supported by a columnar part 3 extending to the opposite direction of these arm parts 4 and 5 from a nearly central part of the connecting part 6. Here, width (w) of this columnar part 3 is more than 0.5 times and less than 1.0 times of width (W0) of these arm parts 4 and 5, while thickness (t) of this columnar part 3 is more than 0.75 times over the thickness t0 of the arm parts 4 and 5, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity sensor for detecting an angular velocity using a tuning fork vibrator made of a piezoelectric material, and is particularly suitable for use as an angular velocity sensor in a vehicle attitude control device.

[0002]

2. Description of the Related Art Conventionally, as this kind of angular velocity sensor,
There is one described in JP-A-8-210860. FIG. 13 shows the configuration. This is provided with a vibrator 1 formed in a substantially U-shaped tuning fork shape having a pair of quadrangular prism-shaped arm portions 4 and 5 and a connecting portion 6 connecting one end of each arm portion 4 and 5 by a piezoelectric body. This is a so-called bulk tuning fork type, in which the vibrator 1 is vibrated at a constant rate, and the Coriolis force applied to the vibrator 1 when the angular velocity Ωz is generated is detected from the change in the vibration of the vibrator 1.

Here, the arrangement direction of the two arms 4 and 5 is the y-axis direction, and a substantially X-shaped side surface X of the vibrator 1 is provided.
When the direction orthogonal to X1 and X2 is defined as the x-axis direction, and the axis parallel to the direction in which the arms 4 and 5 extend and located between the centers of the two arms 4 and 5 is defined as the z-axis, Thus, an xyz rectangular coordinate system is configured (see FIG. 13). In this coordinate system, the above-mentioned angular velocity sensor operates specifically as follows.

When an AC voltage is applied in the x-axis direction to the vibrator 1 polarized in the x-axis direction, the two arms 4, 5 vibrate in the y-axis direction. Then, the vibrator 1 receives a rotational force about the z-axis, that is, the angular velocity Ωz about the z-axis.
Is generated, the arms 4, 5 are moved to x by Coriolis force.
Vibrates in the axial direction. By detecting the vibration in the x-axis direction, the angular velocity Ωz of the vibrator 1 around the z-axis is detected.

[0005]

In the above-described angular velocity sensor, the generated angular velocity Ωz, that is, the input angular velocity is zero.
In this case, it is desirable that the vibration of the arm portions 4 and 5 of the vibrator is only the y-axis direction component. However, since the vibrator 1 is formed of the piezoelectric body, the vibration has a component in the x-axis direction even when the input angular velocity is 0 due to a processing error of the vibrator 1 and non-uniform polarization of the piezoelectric body. .

Further, as shown in FIG.
The connecting portion 6 is supported by a column 3 extending from a substantially center of the connecting portion 6 in a direction opposite to the arms 4 and 5. The column 3 is connected and fixed to the substrate 2 arranged in parallel with the vibrator 1.
Then, it is considered that the vibration component in the x-axis direction is transmitted from the column portion 3 to the substrate 2 (so-called vibration leakage) and becomes an exciting force for generating vibration of the substrate 2 around the z-axis.

The vibration in the x-axis direction and the vibration caused by the vibration are not only offset with respect to the detection signal of the angular velocity, but are unstable as vibration. for that reason,
In particular, when the temperature changes, the vibration becomes unstable.
As a result, it is considered that the temperature drift of the offset output occurs due to such unnecessary vibration, and the sensor performance deteriorates. Note that the temperature drift is a difference between the maximum value and the minimum value of the offset output in the operating temperature range of the sensor.

In view of the above problems, an object of the present invention is to reduce a temperature drift of an angular velocity sensor for detecting an angular velocity using a tuning fork vibrator made of a piezoelectric material.

[0009]

As a result of intensive studies, the present inventors have paid attention to the torsional rigidity of the column 3 supporting the vibrator 1 in consideration of the shape (tuning fork type) of the vibrator 1. That is, if the torsional rigidity is increased, even if there is a processing error in the vibrator 1 or non-uniform polarization of the piezoelectric body,
It is considered that unnecessary vibration (vibration in the x-axis direction) is less likely to occur and temperature drift can be reduced.

Here, the smaller the temperature drift, the better, but further investigations have shown that, in practice, when an angular velocity sensor is used for an automobile which is said to have a severe requirement for the temperature drift, the sensor operating temperature range and the control circuit Considering constraints such as the sensor output correction limit due to
The temperature drift is 10 ° / sec or less (−30 ° C. to 80
° C). By the way, in this kind of conventional angular velocity sensor, the temperature drift is 20 to
Many were at 30 ° / sec, and a level of 10 ° / sec or less could not be stably realized.

By the way, as shown in FIG. 13, the column portion 3 of the above-mentioned conventional angular velocity sensor is thin. If the pillar 3 is absent, or if it is thick, the pillar 3 is made thin because the vibration from the vibrator 1 easily leaks to the electrode substrate 2. The present inventors consider that in the conventional angular velocity sensor, it is necessary to increase the torsional rigidity of the column portion (3), which is a thin portion, and pay attention to the thickness of the column portion (3). The effect of temperature on the temperature drift of the sensor was investigated.

As a result, in the x-axis direction and the y-axis direction,
Width and thickness (w, t) of the column, and the x-axis direction and y-axis
The width and the width of the square pillar which is the arm part (4, 5) in the direction
And thickness (w₀, T₀In the dimensional relationship with
There is a predetermined range that can reduce the
I found that there is. That is, the invention of claim 1
The width (w) of the column (3) in the y-axis direction is the arm
(4, 5) width in the y-axis direction (w₀0.5) or more of 1.)
0 times or less, and the thickness (t) of the column portion (3) in the x-axis direction is
The thickness (t) of the arm portion (4, 5) in the x-axis direction ₀) Of 0.7
5 times or more.

Since the thickness of the column portion (3) has a dimensional relationship with the arm portions (4, 5), the angular velocity sensor in which the temperature drift is reduced to 10 ° / sec or less can be stably performed. realizable. Here, the thickness (t) of the column portion (3) in the x-axis direction is at least 0.75 times the thickness (t ₀ ) of the arm portions (4, 5) in the x-axis direction, but is too thick. In addition, the physical size of the sensor in the x-axis direction becomes excessively large, and the above-mentioned leakage of vibration occurs. Therefore, as described in the second aspect of the present invention, the thickness (t) of the column (3) in the x-axis direction is:
1.0 of the thickness (t ₀ ) of the arm portion (4, 5) in the x-axis direction
It is preferably at most twice.

Further, in the invention according to claim 4, the Young's modulus of the material forming the column (3) is larger than that of the piezoelectric body. Thereby, since the torsional rigidity of the column part (3) is improved, the effect described in claim 1 can be realized. Preferably, the Young's modulus of the material constituting the pillar portion (3) is 10,000 to 10,000.
A 100,000kgf / mm ^2, the Young's modulus of the piezoelectric is about 8,000kgf / mm ^2.

In order to satisfy the fifth aspect, as in the sixth aspect, 42 alloy is used as the column portion (3), and zircon lead titanate (PZT) is used as the piezoelectric body of the vibrator (1). Can be used. The above claim 1
In the sixth to sixth aspects, the drive electrodes (101, 10) provided on one surface (X1) of the first electrode mounting surface (X1, X2) to excite the arms (4, 5) in the y-axis direction.
2) can be as described in claim 7.

According to the present invention, the common electrode (109) is formed on the entire surface (X2) on the other side of the first electrode mounting surface (X1, X2). If it is provided, it can cope with the case where the shape of the drive electrode (101, 102) on one surface (X1) is changed or the case where another electrode is provided on one surface (X1). Can be.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. 1 and 2 show the overall configuration of the angular velocity sensor according to the present embodiment. The sensor according to the present embodiment is used, for example, as an angular velocity sensor of a vehicle behavior control system that prevents a vehicle from skidding or spinning.

As shown in FIG. 1, the angular velocity sensor according to the present embodiment is formed in a tuning fork shape, and has a vibrator 1 provided with electrodes on its outer peripheral surface. A drive / detection circuit (not shown) for detecting an angular velocity Ωz about the z-axis shown in FIG.
And a column part 3 for connecting and fixing and supporting them.

As shown in FIG. 1, the vibrator 1 includes a pair of square pillar-shaped arms 4 and 5 arranged substantially in parallel, and a square pillar-shaped connecting portion 6 connecting one end of each arm 4 and 5. And has a substantially U-shaped tuning fork shape, and is integrally formed of a piezoelectric body. Here, a ceramic piezoelectric material such as lead zirconate titanate (PZT), crystal, or the like can be used as the piezoelectric material constituting the vibrator 1, but the vibrator 1 of the present embodiment can have any polarization direction. P that can be set for easy production
ZT is used.

In the vibrator 1, both arm portions 4,
The X1 plane and the X2 plane, which are the first electrode mounting surfaces on which the 5 and the connecting portion 6 form the same plane, are positioned so as to be parallel to the substrate 2. In the present embodiment, X1
The axis orthogonal to the plane and the X2 plane is the x axis, the axis in the arrangement direction of the arms 4 and 5 is the y axis, and the axis orthogonal to the xy plane formed by the x axis and the y axis is the z axis. Then, an xyz orthogonal coordinate system is configured, and the angular velocity sensor is mounted on the automobile with the z-axis oriented in the vehicle up-down direction.

Here, of the surfaces orthogonal to the y-axis of the arms 4 and 5, the surfaces not facing the two arms 4 and 5 are defined as Y1 (arm 4) and Y2 (arm 4). 5
Side). These Y1 surface and Y2 surface are configured as second electrode mounting surfaces as described later. Further, the column portion 3 supporting the vibrator 1 includes the arm portion 4 of the connecting portion 6,
5 is joined to the surface on the opposite side via a connecting portion 3 a having a length substantially equal to that of the connecting portion 6. Here, pillar 3
Are integrally formed substantially at the center of the connection portion 3a, and the connection portion 3a and the connection portion 6 are joined by, for example, an epoxy-based adhesive. The column portion 3 extends from substantially the center of the connecting portion 6 in a direction opposite to the arm portions 4 and 5, and supports the vibrator 1.

At the lower end of the pillar 3, a base 3b is provided integrally. And the base 3b is the substrate 2
The column 3 is attached by, for example, welding so as to be parallel. Thus, the vibrator 1
Is connected to the substrate 2 via the connecting portion 3a, the pillar portion 3 and the base 3b.
It is fixed to. Here, the three portions of the pillar portion 3, the connection portion 3a, and the base 3b are integrally formed of metal (42 alloy in this embodiment) or the like, but these three portions may be joined to each other. Good.

In order to reduce unnecessary vibration, it is preferable that the torsional rigidity of the column portion 3 is large. Therefore, the material of the column portion 3 has a higher Young's modulus than the piezoelectric body forming the vibrator 1. Is preferred. In the above 42 alloy, the Young's modulus is about 12,000 kgf / mm ² , and PZ
T is about 8,000 kgf / mm ² . As a result of the study by the present inventors, the Young's modulus of the material of the column portion 3 is 10,000 to 100,000 kgf / mm ² at the mild steel level.
Is considered preferable. The details of the examination of the thickness of the column 31 will be described later.

Next, each electrode provided on the vibrator 1 will be described with reference to FIG. As shown in FIG. 2A, one of the X1 surface and the X2 surface, which are the first electrode mounting surfaces, is provided on one of the X1 surfaces in the order from the connecting portion 6 side to the drive electrodes 101, 1
02, monitor electrodes 103 and 104, and polarization electrodes 105 and 106 for polarization processing. Drive electrode 1
01 and 102 pass through the connecting portion 6 and X
Of the one surface, a portion near the Y1 surface and the Y2 surface and a portion near the facing surface of each of the arms 4 and 5 are formed to have a U-shape similar to the shape of the X1 surface.

The monitor electrodes 103 and 104 are formed at portions of the X1 plane near the opposing surfaces of the arms 4 and 5, respectively. Further, as shown in FIGS. 2B and 2C, the angular velocity detecting electrodes 107 and 108 are respectively formed in the Y1 plane and the Y2 plane, which are the second electrode mounting planes, near the X2 plane.

The first electrode mounting surface X1 surface, X2 surface
Of the surfaces, the X2 surface on the other side facing the X1 surface on one side includes:
A common electrode 109 serving as a reference electrode for the drive electrodes 101 and 102, the monitor electrodes 103 and 104, and the angular velocity detection electrodes 107 and 108 is formed. Further, pad electrodes 116 and 117 for extracting detection signals from the angular velocity detection electrodes 107 and 108 are provided via the extraction electrodes 118 and 119, respectively.
And 108.

The X1 plane of each of the arms 4, 5 and X
By using the electrodes provided on the two surfaces, each of the arms 4 and 5 can be polarized in the direction from the X1 plane to the X2 plane along the x-axis, as shown by the outline arrows in FIG. Have been. The polarizing electrodes 105 and 106 are short-circuit electrodes 110 and 111, virtual reference electrodes (virtual GND electrodes) 112 and 113, and short-circuit electrodes 114, respectively.
And the common electrode 109 are short-circuited via the short-circuit electrodes 110, 111, 114, and 1.
15 and the extraction electrodes 118 and 119 are provided after the polarization processing.

As described above, each electrode is connected to both arms 4 and 5.
Are provided symmetrically with respect to each other. Next, a drive / detection circuit (not shown) includes a first input circuit that captures a monitor signal from the monitor electrodes 103 and 104, a second input circuit that captures a detection signal from the angular velocity detection electrodes 107 and 108, and a reference signal based on the monitor signal. Drive electrode 10 as signal
A self-excited oscillation circuit as a driving means for applying a driving signal (AC voltage) between the first and second electrodes 102 and the common electrode 109, and respective speeds Ω around the z-axis based on the monitor signal and the detection signal.
It has a configuration having a detection circuit as detection means for detecting z.

The input and output between each of the above-mentioned electrodes and a drive / detection circuit (not shown) are connected to terminals (terminal portions) 10 to 17 which are insulated from the substrate 2 by, for example, a hermetic seal or the like. Each electrode on the child 1 is connected by wires 20 to 27 by wire bonding. Therefore, by the drive / detection circuit (not shown),
The vibrator 1 of the present embodiment can be operated as follows.

Using the common electrode 109 as a reference potential, the drive electrode 101 and the drive electrode 102 have a phase of 180
By applying different AC voltages in the x-axis direction, the respective arm units 4 and 5 are excited in the y-axis direction. At this time, an output current (monitor signal) flowing between the monitor electrodes 103 and 104 and the common electrode 109 is detected, and self-excited oscillation control is performed so that the amplitude in the y-axis direction is constant even when the ambient temperature changes. Do.

With respect to the vibrator 1, the angular velocity Ωz around the z-axis
Is input, the arms 4 and 5 are moved by Coriolis force.
A vibration proportional to the angular velocity Ωz is generated in the x-axis direction. At this time, an output current (detection signal) proportional to the angular velocity Ωz generated between the angular velocity detection electrodes 107 and 108 and the common electrode 109 is detected, and the angular velocity around the z-axis at the center position of each of the arms 4 and 5 is detected. Ωz is detected.

Next, in the angular velocity sensor having the above structure,
The thickness of the column 31 of the support portion 3 is variously changed so that the temperature drift
We investigated the relationship with Here, the temperature drift is
When the input angular velocity Ωz is 0 in the detection signal
Offset output changes how much when ambient temperature changes
It is an evaluation of whether or not it has been done. FIG. 3 (a) and (b)
As shown in the figure, the present inventors standardize the thickness of the pillar 3.
Therefore, the width w of the column 3 in the y-axis direction is
Width w in the y-axis direction of 4, 5 ₀Ratio w / w with₀Take the pillar
3, the thickness t in the x-axis direction of the arm portions 4, 5
Thickness t₀And the ratio t / t₀Was decided. these
Relationship between each ratio and temperature drift of offset output (° / sec)
I investigated the staff. As described above, the column 3 is made of a 42 alloy.
The arm portions 4 and 5 are made of PZT.

Here, the temperature range of the temperature drift is -30.
C. to 80C. This corresponds to the range of use of the angular velocity sensor for an automobile. The ratio L / L ₀ between the length L of the column 3 in the z-axis direction and the length L ₀ of each of the arms 4 and 5 is 1/17. First, the thickness ratio t / t ₀ was fixed at 1, and the relationship between the width ratio w / w ₀ and the temperature drift was examined.
FIG. 4 shows the results. 3 for each value of width ratio w / w ₀
A total of nine samples were prepared, and the temperature drift was determined for each sample. From this, the temperature drift becomes smaller as the width ratio w / w ₀ is larger.
It can be seen that a temperature drift of 10 ° / sec or less can be stably realized without variation.

Next, the relationship between the thickness ratio t / t ₀ and the temperature drift was examined at the width ratio w / w ₀ = 0.5, which is the lower limit for achieving a temperature drift of 10 ° / sec or less. The result is shown in FIG. For each value of the thickness ratio t / t ₀ , three samples were produced in total, three samples each, and the temperature drift was determined for each sample. From this, it is understood that the temperature drift decreases as the thickness ratio t / t ₀ increases, and that the temperature drift of 10 ° / sec or less can be stably realized without variation if the thickness ratio is at least 0.75 or more.

Therefore, in the pillar portion 3, the width ratio w / w ₀ ≧
It can be seen that if 0.5 and the thickness ratio t / t ₀ ≧ 0.75, an angular velocity sensor having a temperature drift of 10 ° / sec or less can be stably realized. Next, for each of the samples used in FIGS. 4 and 5, it was examined how unnecessary vibrations of the arms 4 and 5 in the x-axis direction and vibrations of the substrate 2 were reduced.

As shown in FIG. 3C, the arms 4, 5
In the vibration state in the x-axis direction, the vibration width Vx in the x-axis direction and the vibration width Vy in the y-axis direction are obtained at the upper end of one of the arms (for example, the arm 5), and the ratio of the two vibration widths ( (Vx / Vy) × 100 (%) is defined as the ratio of oblique vibration. On the other hand, the vibration state of the substrate 2 is obtained by calculating a vibration width U in the x-axis direction at each point on the substrate 2 and calculating a ratio (Umax / Vy) between the maximum value Umax and the vibration width Vy.
X100 was defined and indicated as the substrate vibration ratio. The measurement of each vibration width is based on a known Doppler measurement method in which the vibration velocity is measured and integrated.

The results are shown in FIG. 6 (w / w ₀ and oblique vibration ratio), FIG. 7 (t / t ₀ and oblique vibration ratio), and FIG.
₀ and substrate vibration ratio) and FIG. 9 (t / t ₀ and substrate vibration ratio). From FIG. 6 to FIG. 9, the width ratio w / w ₀ ≧ can stably realize the temperature drift of 10 ° / sec or less.
In the range of 0.5 and the thickness ratio t / t ₀ ≧ 0.75, the ratio of the oblique vibration and the ratio of the substrate vibration are lower than those in the other ranges. The oblique vibration rate is less than about 4%, and the substrate vibration rate is less than about 0.02%. Therefore, it can be seen that unnecessary vibration is certainly reduced in the range of the width ratio w / w ₀ ≧ 0.5 and the thickness ratio t / t ₀ ≧ 0.75.

From the above investigation, it was found that the thickness of the column 3 should be at least a predetermined value for reducing the temperature drift. Here, as the column portion 3 becomes thicker, the torsional rigidity becomes larger, but on the other hand, it is considered that vibration leakage is increased, and unnecessary vibration of the substrate 2 may be increased. Therefore, the present inventors have further investigated to obtain an upper limit of the thickness of the column portion 3.

As a result, as shown in FIG. 10, from the graph, if the width ratio w / w ₀ is approximately 1.4 or more,
A temperature drift of more than 10 ° / sec appeared, and it was found that an angular velocity sensor having good temperature drift performance could not be stably obtained. It is preferable that the width ratio w / w ₀ ≦ 1 based on actual measured values.

As for the thickness ratio t / t ₀ , as shown in FIG. 5, good temperature drift performance can be stably obtained up to the thickness ratio t / t ₀ ≦ 1. Actually, the thickness t of the column portion 3 is substantially equal to or less than the thickness t ₀ of the arm portions 4 and 5 in practical use, because if the thickness is too large, the physical size of the sensor in the y-axis direction becomes large. Is preferred. As described above, according to the present embodiment, the size of the pillar 3 is equal to 0.
If 5 ≦ w / w ₀ ≦ 1 and t / t ₀ ≧ 0.75, an angular velocity sensor having a temperature drift of 10 ° / sec or less can be stably realized. Here, the thickness ratio t / t ₀ is practically preferably 0.75 ≦ t / t ₀ ≦ 1.

Further, in the angular velocity sensor having the above structure, in FIG. 10, the width w of the column 31 is 0.5 to 4.6 m.
m, but a temperature drift of 10 ° / sec or less is realized when the width w is in the range of 1 to 2 mm. At this time, the length w _{1 of} the connecting portion 6 in the y-axis direction (see FIG. 3A) is about 4.6 mm, and the width ratio w / w ₁ is approximately 0.2 to 0.5. It is.

The column portion 3 is not limited to a quadrangular columnar shape, and may have various columnar cross-sectional shapes such as a circle, a diamond, an ellipse, and a polygon other than a square as shown in FIG. Good. Note that the drive electrodes 101 and 102 need not be on the arms 4 and 5, but are at least on the connection 6 and near the ends of the arms 4 and 5 as shown in FIG. There may be.

In the above embodiment, the torsional stiffness is changed by changing the width ratio w / w ₀ and the thickness ratio t / t ₀ of the column 3. However, the torsion is changed by changing the length ratio L / L _0. It is considered that the same effect is obtained even if the rigidity is changed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an overall configuration of an angular velocity sensor according to an embodiment of the present invention.

FIGS. 2A and 2B are explanatory views showing the electrode configuration of FIG. 1, wherein FIG. 2A is a front view, and FIGS. 2B and 2C are side views.

3A and 3B are explanatory diagrams showing a dimensional relationship between a vibrator and a column in FIG. 1, wherein FIG. 3A is a front view, FIG. 3B is a side view, and FIG.

FIG. 4 is a diagram showing a relationship between a width dimension of a pillar portion and a temperature drift in the embodiment.

FIG. 5 is a diagram showing a relationship between a thickness dimension of a pillar portion and a temperature drift in the embodiment.

FIG. 6 is a diagram showing a relationship between a width dimension of a pillar portion and an oblique vibration ratio in the embodiment.

FIG. 7 is a diagram illustrating a relationship between a thickness dimension of a pillar portion and an oblique vibration ratio in the embodiment.

FIG. 8 is a diagram showing a relationship between a width dimension of a pillar portion and a substrate vibration ratio in the embodiment.

FIG. 9 is a diagram showing a relationship between a thickness dimension of a pillar portion and a substrate vibration ratio in the embodiment.

FIG. 10 is a diagram showing a relationship between a width dimension and a temperature drift when the width dimension of the pillar portion of the embodiment is increased.

FIG. 11 is a cross-sectional view showing a modification of the cross-sectional shape of the pillar in the embodiment.

FIG. 12 is a front view showing a modification of the shape of the drive electrode in the embodiment.

FIG. 13 is a perspective view showing a configuration of a conventional angular velocity sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... vibrator, 3 ... pillar part, 4, 5 ... arm part, 6 ... connection part, 101, 102 ... drive electrode, 107, 108 ... angular velocity detection electrode, X1, X2 ... 1st electrode mounting surface, Y1, Y2
... second electrode mounting surfaces, t ... pillar portion thickness, t ₀ ... thickness of the arm portion, w ... pillar portion of the width, w ₀ ... arm portion of the width, w ₁ ... connecting portion of length,? Z ... Angular velocity about the z-axis.

Claims (8)

[Claims] A pair of quadrangular prism-shaped arms (4, 5);
A connecting portion (6) for connecting one end of each arm portion (4, 5);
Consisting of a piezoelectric body formed in a substantially U-shaped tuning fork shape having
A vibrator (1) and the arm portions (4, 5) from substantially the center of the connecting portion (6)
Column extending in the opposite direction to the above and supporting the vibrator (1)
(3) the two arms (4, 5) in the vibrator (1);
A first electrode mounting in which the connection part (6) forms the same plane.
The surface (X1, X2) is provided on one surface (X1).
Drive electrodes (101, 102) and other surface (X2)
A common electrode (109) provided in the arm portion (4, 5);
The second electrode mounting surface (Y
1, Y2), the angular velocity detection electrodes (107, 10
8), wherein the arm portions (4, 5) are provided with the first electrode mounting surface (X
1, X2), and is polarized in the x-axis direction orthogonal to the driving electrodes (101, 102) and the common electrode (10, X2).
9) to apply a voltage to the arm portion (4, 5).
Is excited in the y-axis direction, and the vibrator is
Before being caused by the angular velocity (Ωz) about the predetermined axis in (1)
The vibration state of the arm portions (4, 5) in the x-axis direction is
Angle detected by the angular velocity detection electrodes (107, 108)
In the speed sensor, the width (w) of the column portion (3) in the y-axis direction is equal to the arc width.
Width (w) in the y-axis direction of the₀) 0.5 times
Not less than 1.0 times, and the x-axis direction of the pillar portion (3)
The thickness (t) in the direction is the x-axis of the arm portion (4, 5).
Thickness in the direction (t ₀) Is 0.75 times or more
Angular velocity sensor. 2. The thickness (t) of the column portion (3) in the x-axis direction is not more than 1.0 times the thickness (t ₀ ) of the arm portions (4, 5) in the x-axis direction. The angular velocity sensor according to claim 1, wherein 3. The width (w) of the column portion (3) in the y-axis direction is 0.2 to 0.5 times the width (w ₁ ) of the connecting portion (6) in the y-axis direction. The angular velocity sensor according to claim 1, wherein the angular velocity sensor is provided. 4. A substantially U-shaped tuning fork-shaped piezoelectric element having a pair of quadrangular prism-shaped arms (4, 5) and a connecting part (6) for connecting one end of each arm (4, 5). A vibrator (1) made of a body, and the arm portions (4, 5) from substantially the center of the connecting portion (6)
A column portion (3) extending in the opposite direction to support the vibrator (1), and the two arm portions (4, 5) and the connecting portion (6) in the vibrator (1) form the same plane. Of the first electrode mounting surfaces (X1, X2), the drive electrodes (101, 102) provided on one surface (X1) and the other surface (X2)
A common electrode (109) provided in the arm portion (4, 5);
The second electrode mounting surface (Y
1, Y2), the angular velocity detection electrodes (107, 10
8), wherein the arm portions (4, 5) are provided with the first electrode mounting surface (X
1, X2), and is polarized in the x-axis direction orthogonal to the driving electrodes (101, 102) and the common electrode (10, X2).
9) to apply a voltage to the arm portion (4, 5).
Is excited in the y-axis direction, and the vibration state of the arms (4, 5) in the x-axis direction caused by the angular velocity (Ωz) of the vibrator (1) around a predetermined axis is determined by the angular velocity detection electrode ( 107), wherein the Young's modulus of the material forming the column portion (3) is larger than the Young's modulus of the piezoelectric body. 5. The Young's modulus of the material forming the column portion (3) is 10,000 to 100,000 kgf / mm ² , and the Young's modulus of the piezoelectric body is about 8,000 kgf / mm.
The angular velocity sensor according to claim 4, characterized in that the mm ^2. 6. The pillar (3) is made of 42 alloy,
The angular velocity sensor according to claim 1, wherein the piezoelectric body is lead zirconate titanate. 7. The drive electrode (101, 102) has a shape similar to the shape of the first electrode mounting surface (X1, X2), and is closer to one of the arm portions (4, 5). The angular velocity sensor according to any one of claims 1 to 6, wherein the angular velocity sensor is formed continuously from the second arm portion side through the connecting portion (6). 8. The device according to claim 1, wherein the common electrode is provided on the entire surface on the other side of the first electrode mounting surface. 9. The angular velocity sensor according to claim 1.