JP3244924B2 - Angular velocity sensor - Google Patents

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 used for attitude control of a moving body such as an automobile, an aircraft, a ship, a vehicle, and the like, and a navigation system.

[0002]

2. Description of the Related Art A conventional angular velocity sensor is disclosed in
No. 1853, "A drive unit for a plate-shaped piezoelectric body and a detection unit for the plate-shaped piezoelectric body are arranged so as to be orthogonal to each other so as to cut off capacitive coupling, and the drive unit is vibrated by applying an AC drive voltage. In this case, an angular velocity is obtained by detecting a bending state of the detection unit in a direction orthogonal to the vibration direction.

Hereinafter, this conventional angular velocity sensor will be described with reference to the drawings. FIG. 13 is a perspective view of a conventional angular velocity sensor. In FIG. 13, reference numerals 1 and 1 ′ denote a driving piezoelectric bimorph (driving unit) in which two piezoelectric bodies are bonded with an adhesive or the like.
Reference numerals 2 and 2 'denote detection piezoelectric bimorphs (detection units) each formed by laminating two piezoelectric bodies similarly to the driving piezoelectric bimorphs 1 and 1'. The driving piezoelectric bimorphs 1 and 1 'and the detection piezoelectric bimorph 2 , 2 'are integrally fixed by metal joints 3, 3' so as to be orthogonal to each other. 7,7 '
Is an insulator interposed between the driving piezoelectric bimorphs 1, 1 'and the metal joints 3, 3', and 8, 8 'is between the detecting piezoelectric bimorphs 2, 2' and the metal joints 3, 3 '. Each is an interposed insulator. Reference numerals 9, 9 'denote lead wires for connecting the piezoelectric bodies on one side of the driving piezoelectric bimorphs 1, 1' and the metal joints 3, 3 ', respectively, and reference numerals 10, 10' denote detection piezoelectric bimorphs 2, 2 'and the metal joints 3. , 3 'respectively, lead wires 11 and 11' are respectively connected to the piezoelectric bodies on the other surface of the driving piezoelectric bimorphs 1 and 1 ',
Reference numerals 12 and 12 'denote lead wires connected to the piezoelectric bodies on the other surfaces of the detection piezoelectric bimorphs 2 and 2', respectively.

A piezoelectric body on one side inside the driving piezoelectric bimorphs 1, 1 'is fixed to a metal terminal 4 by welding, soldering or the like, and the metal joints 3, 3' are grounded via the metal terminal 4. ing. Then, an AC driving voltage is applied to the driving piezoelectric bimorphs 1 and 1 'via the lead wires 11 and 11'. In addition, the detection piezoelectric bimorph 2,
A detection signal due to the bending of the 2 'is taken out from the lead wires 12, 12'.

[0005]

However, in the configuration of the above-mentioned prior art, the driving piezoelectric bimorphs 1 and 1 'and the detecting piezoelectric bimorphs 2 and 2' are constructed by laminating two piezoelectric bodies with an adhesive or the like. Because the temperature changes in the external environment, the thermal expansion of the adhesive or the like, or the orthogonal angle of the bent metal plate changes, when the input angular velocity is 0, the output value fluctuates due to the temperature change, and the temperature drift fluctuates greatly. Had the problem that

Also, variations in dimensions, thickness, bonding, and the like of piezoelectric bodies bonded to the driving piezoelectric bimorphs 1 and 1 'and the detection piezoelectric bimorphs 2 and 2', and the driving piezoelectric bimorphs 1 and 1 'and the detection Piezo bimorph 2, 2 '
And there is a problem that the angular velocity cannot be detected with high accuracy. SUMMARY OF THE INVENTION An object of the present invention is to provide an angular velocity sensor which has excellent temperature characteristics in a wide temperature range and has little variation in solving various problems in the related art.

[0007]

According to the angular velocity sensor of the present invention, a desired crystal axis and a crystal blank cut out in the plane thereof are processed by a mechanical or electric processing method, and the vibrating arm is formed only by the crystal blank. A pair of substantially U-shaped tuning-fork type quartz vibrators are formed symmetrically arranged, one of which is a driving-side tuning fork and the other is a detecting-side tuning fork. Integral configuration separate for detection, ie 2
Two substantially U-shaped tuning-fork type quartz vibrators are integrally formed via a connector at a support portion which is a base of two vibrating arms so as to face each other in parallel to each other.

The binding site of the connector with respect to the support portion is substantially U
It is desirable to have a portion where the mechanical Q value of the character-shaped tuning-fork type quartz vibrator has a small decrease and the vibration can be transmitted effectively. For example, in the support portion, regions having a certain area including a vibrating node (the meaning of which will be described later) may be integrally formed via a connector. As described above, when the drive-side tuning fork and the detection-side tuning fork are fixed to each other with a certain area including the vibrating node generated in the support portion via the block-shaped connector, the energy confinement theory is used. In addition, the mechanical Q value of the tuning fork vibration and the mechanical transmission efficiency from the driving side tuning fork to the detection side tuning fork can be maximized. Therefore, the mechanical transmission loss in the substrate of the conventional tuning fork coupling portion can be remarkably improved, and the sensitivity of the angular velocity detection by the Coriolis force can be remarkably improved.

[0009] Even if other portions of the support portion, such as the bottom surface of the support portion, are connected to each other, the vibration can be transmitted from the drive side to the detection side, so that the coupling portion is not limited to the above-described vibration node. is there. As described above, according to the present invention, the direction (X) connecting the two vibrating arms of the driving-side tuning fork is set so that one of the driving-side tuning forks maintains the driving vibration, and the other detection-side tuning fork detects the Coriolis force. Axial direction), that is, equipped with an electrode for extracting an electrical signal of a vibration component in a direction perpendicular to the bending vibration direction with a tuning fork on the detection side, and detecting angular velocity, temperature drift is extremely small and highly accurate. An inexpensive angular velocity sensor can be obtained.

Further, since a substantially U-shaped tuning-fork type quartz vibrator in which the vibrating arm and the supporting portion are integrally connected is used, there are no various manufacturing steps such as a piezoelectric element attaching step as in the conventional example, and the temperature is reduced. An object is to obtain a stable angular velocity sensor without variation. Hereinafter, a description will be given corresponding to each claim. Claim 1
The angular velocity sensor described above cuts out a new crystal axis X, Y ', Z' rotated around the X axis of the crystal axes X, Y, Z in the X, Y 'plane with the Y' axis direction as a longitudinal direction, A substantially U-shaped tuning fork-shaped quartz blank having a shape in which one and the other symmetric vibrating arms of a rectangular cross section are connected in parallel and integrally by a support portion, and an electrode is arranged on the peripheral surface of the one and the other vibrating arms. 1 and a Y ', Z' plane with the Y 'axis direction of new crystal axes X, Y', Z 'rotated around the X axis of the crystal axes X, Y, Z as the longitudinal direction. An electrode is arranged on the peripheral surface of the one and other vibrating arms of a substantially U-shaped tuning fork-shaped quartz blank having a shape in which one and the other symmetric vibrating arms of a rectangular cross section are connected in parallel and integrally at a support portion. And a second tuning fork-shaped crystal resonator formed as described above is supported via a connector in a state where the second tuning fork-shaped crystal resonator faces each other in parallel with each other. Wherein the first tuning-fork type quartz vibrator is displaced in the X-axis direction of one and the other vibrating arms by applying an AC voltage through an electrode. Wherein the second tuning-fork type quartz vibrator is displaced in the Z′-axis direction propagated from the first tuning-fork type quartz vibrator via the coupler, and has opposite phases of bending. Angular velocity detection detection for detecting, via an electrode, AC voltages generated by vibrations of opposite phases in the X-axis direction of one and the other vibrating arms, which are generated by the Coriolis force based on the vibration and the rotational angular velocity about the Y'-axis, via electrodes. It is characterized by a side tuning fork.

[0011] The angular velocity sensor according to the second aspect is the first aspect.
In the angular velocity sensor described above, the resonance frequency of the opposite-phase bending vibration displaced in the X-axis direction of the drive-side tuning fork is substantially equal to the resonance frequency of the opposite-phase bending vibration in the X-axis direction of the detection-side tuning fork, and The resonance frequency of the opposite-phase bending vibration displaced in the X-axis direction of the driving-side tuning fork and the resonance frequency of the opposite-phase bending vibration displaced in the Z′-axis direction of one and the other vibrating arms of the detection-side tuning fork are different. Differently, the vibrating arm of the drive-side tuning fork and the vibrating arm of the detection-side tuning fork are set to have different shapes and sizes.

The angular velocity sensor according to the third aspect is the first aspect.
In the angular velocity sensor described above, the resonance frequency of the opposite-phase bending vibration of the driving-side tuning fork displaced in the X-axis direction, the resonance frequency of the opposite-phase bending vibration of the detection-side tuning fork in the X-axis direction, and one of the detection-side tuning forks. The vibrating arm of the drive-side tuning fork and the vibrating arm of the detection-side tuning fork are different from each other so that the resonance frequencies of the opposite-phase bending vibrations displaced in the Z′-axis direction of the other vibrating arm are different from each other. It is characterized in that it is set to the shape and dimensions.

[0013] The angular velocity sensor according to the fourth aspect is the first aspect.
In the angular velocity sensor described above, the electrodes disposed on the peripheral surface of one and the other vibrating arms of the drive-side tuning fork are respectively provided on the four peripheral surfaces of the front and back surfaces and both sides of the one and the other vibrating arms when viewed in the Z ′ axis direction. The four vibrating arms are provided in a state of being divided into four in the circumferential direction. The front and back electrodes of the one vibrating arm and the both side electrodes of the other vibrating arm are connected in common. The electrodes that connect the front and back electrodes and the electrodes on both sides of the one vibrating arm in common and that are arranged on the peripheral surface of one and the other vibrating arms of the detection-side tuning fork are one and the other as viewed in the X-axis direction. Are provided on the front and back surfaces of the vibrating arm and on the four peripheral surfaces on both sides thereof in a state of being divided into four in the circumferential direction by four ridge lines, respectively, and the front and rear electrodes of the one vibrating arm and both side surfaces of the other vibrating arm Connect the electrode and the common vibrating arm Characterized in that the two side electrodes of the one vibrating arm and electrode connected in common.

The angular velocity sensor according to the fifth aspect is the first aspect of the invention.
In the angular velocity sensor described above, the connector is a columnar shape having both end faces having an area, and both end faces are bonded to a surface partially including a vibrating node generated in a supporting portion of the driving-side tuning fork and the detection-side tuning fork. It is characterized by having. The angular velocity sensor according to claim 6 is the angular velocity sensor according to claim 1, wherein the driving-side tuning fork and the detection-side tuning fork each have a through-hole having a certain area partially including a vibration node generated in the support portion. The connector has a columnar shape, and is bonded to the supporting portions of the drive-side tuning fork and the detection-side tuning fork in a state where both ends are inserted through the through holes.

[0015]

According to the first aspect of the present invention, an AC voltage is applied to the first tuning-fork type quartz vibrator serving as the driving-side tuning fork via an electrode, so that one of the vibrating arms of the other tuning arm is applied to the driving-side tuning fork. Bending vibrations of opposite phases displaced in the X-axis direction are generated. The bending vibrations of opposite phases displaced in the X-axis direction are as follows.
When the rotational angular velocity about the Y 'axis is applied (the same rotational angular velocity is given to the second tuning-fork type quartz oscillator as a matter of course), the first
The first and second vibrating arms of the first tuning-fork type quartz vibrator generate bending vibrations of opposite phases in the Z'-axis direction due to Coriolis force based on the rotational angular velocity of the tuning fork-shaped crystal vibrator around the Y 'axis. . An AC voltage generated by bending vibrations of the one and the other vibrating arms of the second tuning-fork type quartz vibrator propagating through the coupler and having opposite phases in the X-axis direction of the vibrating arms is detected through the electrodes. Since this AC voltage takes a value proportional to the rotational angular velocity around the Y 'axis, the rotational angular velocity around the Y' axis can be detected from the AC voltage.

According to the second aspect of the invention, the resonance frequency of the opposite-phase bending vibration of the driving-side tuning fork displaced in the Z'-axis direction and the resonance of the opposite-phase bending vibration of the detection-side tuning fork in the X-axis direction. The resonance frequencies of bending vibrations having substantially the same frequency and opposite to each other and displacing in the X-axis direction of the drive-side tuning fork, and bending opposite to each other and displacing in the Z'-axis direction of one and the other vibrating arms of the detection-side tuning fork. When the driving-side tuning fork is driven resonantly due to the difference in resonance frequency of the vibration, the detection-side tuning fork has a Coriolis based on bending vibrations of opposite phases displaced in the Z'-axis direction and a rotational angular velocity around the Y'-axis. Opposite-phase bending vibrations in the Z'-axis direction generated in one and the other vibrating arms of the detection-side tuning fork by force can be efficiently detected, and the influence of the opposite-phase bending vibrations displaced in the Z'-axis direction is small. Become. As a result, it is possible to effectively detect the AC voltage generated by the opposite-phase bending vibrations in the X-axis direction while suppressing the influence of the AC voltage generated by the opposite-phase bending vibrations displaced in the Z′-axis direction, and to accurately detect the AC voltages. It is possible to detect the rotational angular velocity around the Y 'axis.

According to the third aspect of the present invention, the resonance frequency of the opposite-phase bending vibration of the drive-side tuning fork displaced in the X-axis direction and the resonance frequency of the opposite-phase bending vibration of the detection-side tuning fork in the X-axis direction. And Z 'of one and the other vibrating arms of the detection-side tuning fork
Since the resonance frequencies of the opposite-phase bending vibrations displaced in the axial direction are separated from each other, when the driving-side tuning fork is driven in resonance, the opposite-phase bending vibrations displaced in the X-axis direction and the Y′-axis are displaced in the X-axis direction. On the other hand, the detection-side tuning fork is displaced in the Z'-axis direction in response to the opposite-phase bending vibrations in the Z'-axis direction generated in one and the other vibrating arms of the driving-side tuning fork due to the Coriolis force based on the surrounding rotational angular velocity. Bending vibrations of opposite phases do not affect each other. As a result, it is possible to effectively detect the AC voltage generated by the opposite-phase bending vibrations in the X-axis direction while suppressing the influence of the AC voltage generated by the opposite-phase bending vibrations displaced in the Z′-axis direction, and to accurately detect the AC voltages. It is possible to detect the rotational angular velocity around the Y 'axis.

According to the configuration of the fourth aspect, an alternating voltage is applied between the two sets of commonly connected electrodes of the drive-side tuning fork to generate bending vibrations of opposite phases displaced in the X-axis direction. At this time, the frequency of the AC voltage is equal to X of one and the other vibrating arms.
The drive-side tuning fork is driven resonantly by setting the resonance frequencies close to the resonance frequencies of the bending vibrations of opposite phases displaced in the axial direction. On the other hand, an AC voltage is generated between the two sets of commonly connected electrodes of the detection-side tuning fork due to bending vibrations of the opposite phases in the X-axis direction generated in one and the other vibrating arms.

According to the fifth aspect of the invention, the bending vibrations of the driving phase tuning fork which are displaced in the X-axis direction in the X-axis direction can be efficiently used without lowering the mechanical Q value of the driving tuning fork. Is transmitted as bending vibrations of opposite phases displaced in the Z'-axis direction. According to the configuration of the sixth aspect, the bending vibrations of the opposite phases displaced in the Z′-axis direction of the driving-side tuning fork are efficiently applied to the detection-side tuning fork without reducing the mechanical Q value of the driving-side tuning fork. It will be transmitted as bending vibrations of opposite phases displaced in the axial direction.

Here, the reason why the two substantially U-shaped tuning-fork type quartz vibrators are connected and integrated via a connector will be described. In the tuning-fork type quartz resonator, one and the other vibrating arms are supposed to be vibrating in a resonant bending vibration (X mode vibration) at + V and -V speeds in the X-axis direction through the Y-axis and symmetrically in the YZ plane. Shall be. Assuming that a rotation at an angular velocity ω is applied in the direction of rotating the Y axis of the tuning fork crystal resonator, Coriolis force is applied to each vibrating arm in a direction symmetric to the Y axis (vibration in the Z axis; vibration in the Z mode). appear. At this time, the generated vibration symmetrical with respect to the Y axis vibrates in the Z-axis direction orthogonal to the bending vibration driven by resonance.

However, in a single tuning-fork type quartz resonator, the resonance frequency of the X mode driven by resonance and the non-resonance frequency of the Z mode newly generated in synchronism therewith are the same, so that they are separated. It is generally difficult.
This is because even if the two modes can be successfully separated and detected by devising the separation electrode arrangement or the like, the detection level is extremely low with respect to the strong level of the resonance drive. This is due to the fact that the detection level is masked or affected, making it impossible to perform accurate detection. Thus, some solution for separating drive and detection by frequency differences was desired.

Therefore, the present invention solves this difficulty by joining two substantially U-shaped tuning-fork type quartz vibrators via a connector to separate them into a drive side and a detection side.
In the present invention, the crystal resonator itself has a pair of vibrating arms arranged in plane symmetry, and one of two substantially U-shaped tuning fork-shaped crystal resonators having a tuning fork shape is a driving side tuning fork, and the other is a driving side tuning fork. It is a detection-side tuning fork and integrated with a connector.

By using quartz as a material for these tuning forks, the angular velocity detection sensitivity is high, the thermal expansion coefficient is small, and the X-mode bending vibration is caused by the electrode arrangement, so that the frequency dependence of the quartz on the temperature change is increased. This leads to a reduction in the temperature drift of the angular velocity sensor, resulting in a reduction in the temperature drift of the angular velocity sensor. In addition, the driving signal component on the driving side is less mixed into the detection side as an unnecessary signal component, the resonance frequency fluctuation at the time of driving is small, and the phase shift change at the time of synchronous detection is small. As a result, an angular velocity sensor having excellent temperature characteristics in a wide temperature range can be obtained.

Here, the operation of the present invention will be described a little more. This means that a new vibration mode (in this case, Z mode) due to Coriolis force is generated (absolutely not resonance) in a tuning fork that vibrates in a specific driving mode (in this case, X mode) that vibrates greatly. Therefore, the generated new vibration mode (in this case, Z mode, but the frequency is synchronized with the drive mode, so it is the same as the drive mode) is selectively (a kind of mechanical filtering) by mode resonance. It is to detect.

That is, if the drive side vibration mode is mixed with the detection side tuning fork, erroneous detection may occur (because the level is isolated to 100 dB), so that the detection vibration mode can be selected from the drive vibration mode. As described above, the electrode structure of the detection-side tuning fork is different from that of the driving-side tuning fork, and the shape and size of the vibrating arm are different so as to provide resonance selection characteristics with respect to the resonance frequency. In the detection side tuning fork,
The drive mode is suppressed as much as possible, and only the detection mode is detected as efficiently as possible.

In the present invention, since a plurality of vibration modes are handled, measures against them are important points. That is, the bending vibrations having opposite phases displaced in the X-axis direction are transmitted from the support portion of the first tuning-fork type quartz vibrator of the driving-side tuning fork via the coupler to the second tuning-fork type quartz vibrating which is the detection-side tuning fork. Partially propagated to the support of the child, but the X of the second tuning fork
Since it is set so that the resonance frequency and the bending vibration of the opposite phases displaced in the axial direction do not coincide with each other and do not resonate, most are confined in the drive-side tuning fork. At this time, if the rotation angular velocity around the Y 'axis is given to the first tuning fork crystal resonator (the same rotation angular velocity is given to the second tuning fork crystal resonator as a matter of course), the first tuning fork crystal resonator is given the second rotation by the Coriolis force. Bending vibrations having opposite phases in the Z'-axis direction of one and the other vibrating arms of the tuning fork-shaped quartz resonator 1 are newly generated. The flexural vibrations having opposite phases in the Z'-axis direction propagate to the second tuning-fork type quartz vibrator through the coupler, and are set to be substantially equal to the resonance frequency of the flexural vibrations having opposite phases in the Z'-axis direction. If it is, it can be detected efficiently.

The detection using the resonance phenomenon is highly sensitive and efficient, so that it is suitable for miniaturization and high accuracy, but has a disadvantage that it is susceptible to other signal interference. In addition, when a large number of different vibrations such as bending vibrations having opposite phases in the X-axis direction or bending vibrations having opposite phases in the Z'-axis direction are to be used, it is necessary to eliminate and suppress interference due to unnecessary vibration. Special attention must be paid to A relatively easy countermeasure is to set the resonance frequencies apart from each other or to avoid proximity, at the expense of some sensitivity.

Fortunately, since these various vibrations are orthogonal to each other and the boundary conditions are independent of each other, there is an advantage that they are easy to control without mutual interference. For example, the bending vibration displacing in the Z′-axis direction and the bending vibration displacing in the X-axis direction use the length of the vibrating arm as a common boundary condition for frequency determination, while the thickness and width are other boundary conditions. Therefore, by making the thickness and the width different from each other in addition to the difference between the piezoelectric constants, the resonance frequencies can be very easily isolated and set differently.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of an angular velocity sensor according to a first embodiment of the present invention. FIG. 1A is a perspective view in an assembled state, and FIG. 1B is a perspective view in an exploded state. In FIG. 1, reference numeral 21 denotes a first tuning fork-shaped quartz vibrator made of a substantially U-shaped tuning fork-shaped quartz blank having a shape in which one and the other symmetrical vibrating arms 24 and 25 having a rectangular cross section are connected in parallel and integrally by a support portion 23, respectively. The drive electrode 22 is cut out by a working (hereinafter referred to as a drive-side tuning fork) by electric processing or mechanical processing, and driving electrodes 22 are arranged on the peripheral surfaces of the one and the other vibrating arms 24 and 25. Reference numeral 26 denotes a second tuning-fork type crystal resonator (hereinafter, referred to as a second tuning-fork type crystal resonator) comprising a substantially U-shaped tuning-fork type crystal blank having a shape in which one and the other symmetrical vibrating arms 29 and 30 having the same rectangular cross section are connected in parallel and integrally by the support portion 28. , A detection-side tuning fork), and a detection electrode 27 is disposed on the peripheral surface of one and the other vibrating arms 29, 30.

Numeral 31 is a connector made of quartz, and both ends of the driving side vibrating node are located at substantially the center surfaces of the driving side support portions 23 and the detection side support portions 28 of the driving side tuning fork 21 and the detection side tuning fork 26, respectively. Is partially bonded to a bonding portion 33 partially including the detection-side vibrating node to form an angular velocity sensor. In this case, the drive-side tuning fork 21 and the detection-side tuning fork 26 face each other in parallel to each other. The connector 31 has a function of transmitting the vibration of the drive-side tuning fork 21 to the detection-side tuning fork 26, and the connector 31 forms a tuning fork together with the drive-side tuning fork 21 and the detection-side tuning fork 26. It is considered that

A substantially U-shaped tuning fork crystal blank used for the driving tuning fork 21 and the detection tuning fork 26, which are the main components, will be described below. FIG. 2 is a perspective view of a substantially U-shaped tuning fork crystal blank used for the driving tuning fork 21, and FIG.
FIG. 6 is a perspective view of a substantially U-shaped tuning fork crystal blank used for No. 6;
In FIG. 2, reference numeral 34 denotes a substantially U-shaped tuning fork crystal blank having a substantially concave shape used for the driving-side tuning fork 21. This crystal blank 34 has new crystal axes X, Y ', rotated by an angle θ (= 1 to 3 °) around the X axis with respect to the crystal axes X, Y, Z.
The two vibrating arms 35A and 35B are cut out in the X and Y 'planes with the Y' axis direction of Z 'as the longitudinal direction.
Are connected by a support portion 35C.

In FIG. 3, reference numeral 34 'denotes a substantially U-shaped tuning fork-shaped crystal blank having a substantially concave shape used for the detection-side tuning fork 26. The crystal blank 34 'extends in the Y'-axis direction of new crystal axes X, Y', Z 'rotated around the X axis by an angle θ (= 1 to 5 °) with respect to the crystal axes X, Y, Z. The vibrating arms 35A 'and 35B' are cut out in the Y 'and Z planes in the direction, and have a structure in which two parallel vibrating arms 35A' and 35B 'are connected by a support 35C'.

Here, an example of the dimensions of the crystal blank constituting the substantially U-shaped tuning fork crystal resonator will be described. For example, the vibrating arm of the drive-side tuning fork is made of quartz in a U-shape and has a length (L) of 10 mm, a thickness (t) of 2.5 mm, and a width (W) of 3.5 mm.
Molding is performed in the cutting direction shown in FIG.
The dimensions of the drive-side tuning fork and the detection-side tuning fork are not limited to the above example, and the dimensions of both tuning forks need not be the same.
It is set appropriately according to the resonance frequency of the Z mode. Also,
The vibrating arm of the tuning fork on the detection side has a U-shaped quartz crystal with a length (L) of 1
It is molded in the cut direction shown in FIG. 3 with dimensions of 0 mm × thickness (t) 3.5 mm × width (W) 2.5 mm. The dimensions of the drive-side tuning fork and the detection-side tuning fork are not limited to the above examples, and the dimensions of both tuning forks need not be the same, and are set as appropriate according to the resonance frequencies of the X mode and the Z mode.

The substantially U-shaped tuning fork crystal blanks 34, 3
When 4 ′ is used for the drive-side tuning fork 21 and the detection-side tuning fork 26 of the angular velocity sensor shown in FIG. 1, the resonance of the bending vibration (hereinafter, referred to as “X mode”) displaced in the X-axis direction of the drive-side tuning fork 21. The resonance frequency of the frequency and the pair of vibrating arms of the detection-side tuning fork 26 is equal to the resonance frequency of the bending vibration of the opposite phase in the X-axis direction, and the X-mode resonance frequency of the driving-side tuning fork 21 and the pair of vibrations of the detection-side tuning fork 26. The arm is cut out and used in such a shape and size that the resonance frequencies of bending vibrations of opposite phases in the Z′-axis direction (hereinafter referred to as “Z mode”) are different.

The drive-side tuning fork 21 is provided with a drive electrode 22
By applying an AC voltage through the first and second vibrating arms, bending vibrations of opposite phases displaced in the X-axis direction of one and the other vibrating arms 24 and 25 are generated. In this case, the resonance drive is performed with the frequency of the AC voltage substantially equal to the resonance frequency of the bending vibrations having opposite phases displaced in the X-axis direction. On the other hand, the detection-side tuning fork 26 is generated by a Coriolis force based on bending vibrations of opposite phases displaced in the Z′-axis direction of the driving-side tuning fork 21 via the connector 31 and a rotational angular velocity around the Y′-axis. An AC voltage generated by bending vibrations of the other vibrating arms 29 and 30 in mutually opposite phases in the X-axis direction is detected via the electrodes.

Hereinafter, a specific configuration of the driving electrode 22 as a main part will be described. FIG. 4A is a connection diagram of a drive electrode 22 formed on the peripheral surface of one and the other vibrating arms of the drive-side tuning fork 21 which is a main part. In FIG. 4A, reference numerals 36a and 36c denote driving electrodes formed on the front surface and the back surface, respectively, as viewed from the Z 'axis direction of one vibrating arm 24, and 36b and 36d denote driving electrodes in the Z' axis direction of one vibrating arm 24. It is a driving electrode formed on both sides as viewed from above.
Reference numerals 37a and 37c denote driving electrodes formed on the front surface and the rear surface, respectively, of the other vibrating arm 25 viewed from the Z 'axis direction.
Drive electrodes 7b and 37d are formed on both sides of the other vibrating arm 25 when viewed in the Z'-axis direction. As shown in FIG. 1, one and the other vibrating arms are viewed in the Z'-axis direction. Are provided on the four peripheral surfaces on the front, back, and both sides, respectively, in a state of being divided into four in the circumferential direction at four ridge portions.

The driving electrodes 36a and 36c on the front and back surfaces of one vibrating arm 24 and the driving electrodes 37b and 37d on both side surfaces of the other vibrating arm 25 are commonly connected. Are commonly connected to the drive electrodes 37a and 37c and the drive electrodes 36b and 36d on both side surfaces of one vibrating arm 24. Driving electrodes 36a, 36c, 37b, 37
d, and the driving electrodes 36b, 36d, 3
The common connection of 7a and 37c is performed by extending the electrode pattern on the peripheral surfaces of the vibrating arms 24 and 25.

Numeral 38 denotes drive electrodes 36a, 3 which are connected in common.
Common lines connected to 6c, 37b, 37d, 39 are commonly connected driving electrodes 36b, 36d, 37a, 37c.
It is a common line connected to. The operation of the driving tuning fork 21 configured as described above will be described.
If a drive signal (AC voltage) is applied between the driving arms 8 and 39 to perform resonance driving, bending vibrations of the one and the other vibrating arms 24 and 25 in opposite phases in the X-axis direction are generated, and one of the driving tuning forks 21 is driven. Vibrating arm 24 and the other vibrating arm 25 open and close. More specifically, for example, when a voltage is applied to the drive electrode 22 with the common line 38 as the positive electrode and the common line 39 as the negative electrode, an electric field is applied in the direction of the arrow in FIG. Vibrating arm 2 in X-axis direction
The inside of 4, 25 is strengthened and the outside is weakened. Therefore,
Since the strengthened portion expands and the weakened portion contracts, the vibrating arms 24 and 25 bend outwardly from each other, and perform a so-called opposite-phase bending vibration. When the polarity of the applied voltage is reversed, the vibrating arm 2
4 and 25 will bend inward mutually.

Hereinafter, the detection electrode 27 as a main part will be described. FIG. 4B shows a main part of the detection-side tuning fork 26.
FIG. 9 is a connection diagram of a detection electrode 27 formed on the peripheral surface of one and the other vibrating arms. In FIG. 4B, 40a,
Reference numeral 40c denotes detection electrodes formed on the front surface and the back surface of the one vibrating arm 29 when viewed from the X-axis direction.
Reference numeral d denotes detection electrodes formed on both sides of one vibrating arm 29 when viewed from the X-axis direction. 41a and 41c are detection electrodes formed on the front and back surfaces of the other vibrating arm 30 when viewed from the X-axis direction, and 41b and 41d are formed on both side surfaces of the other vibrating arm 30 when viewed from the X-axis direction. As shown in FIG. 1, as shown in FIG. 1, when viewed in the X-axis direction, one and the other vibrating arms are divided into four in the circumferential direction at four ridges on the front and back surfaces and on the four circumferential surfaces on both sides. Each is provided.

The detection electrodes 40a and 40c on the front and back surfaces of one vibrating arm 29 and the detection electrodes 41b and 41d on both side surfaces of the other vibrating arm 30 are connected in common, and the front and back surfaces of the other vibrating arm 30 are connected. And the detection electrodes 40b and 40d on both sides of one vibrating arm 29 are commonly connected. Detection electrodes 40a, 40c, 41b, 41
d, and the detection electrodes 40b, 40d, 4
The common connection of 1a and 41c is performed by extending the electrode pattern on the peripheral surfaces of the vibrating arms 29 and 30.

Reference numeral 42 denotes a commonly connected detection electrode 40a, 4
Common lines connected to Oc, 41b, 41d, 43 are commonly connected detection electrodes 40b, 40d, 41a, 41c.
It is a common line connected to. The operation of the detection-side tuning fork 26 will be described. Since the same electrode arrangement as that of the driving-side tuning fork 21 is performed, the vibrating arms 29,
As a result, + and-charges as shown are generated on the detection electrodes 41a to 41d on the front and back surfaces, and an output voltage proportional to the angular velocity appears between the common lines 42 and 43. Since the vibrating arms 29 and 30 are expanded and contracted in opposite phases, opposite charges are generated, and the output of the two vibrating arms 29 and 30 is doubled.

Hereinafter, the vibrating nodes shown as the driving-side vibrating nodes 32 and the detecting-side vibrating nodes 33 in FIG. 1 will be described in detail. FIG. 5 is a side view of the substantially U-shaped tuning fork crystal blank 34, showing a configuration for detecting vibration nodes. FIG. 6A is a perspective view of a substantially U-shaped tuning fork crystal blank 34 showing the position of a vibrating node, and FIG. 6B is a front view of FIG.
(C) is a side view similarly.

In FIG. 5, the substantially U-shaped tuning fork crystal blank 34 is held by a symmetrical pinpoint support 43 so as to sandwich the supporting portion 35C of the substantially U-shaped tuning fork crystal blank 34. An electric signal is given to the blank 34 to give a direction in which the vibrating arms 35A and 35B open and close, that is, an X-mode bending vibration, as shown in the arrow direction (X-axis direction) in FIGS. Then, the mechanical sharpness of bending vibration (resonance) (hereinafter referred to as “mechanical Q value”) is measured, and a point at which the mechanical Q value decreases little is measured. FIG.
The hatched portions below the curves AMB and BNC shown in (a), (b) and (c) indicate portions where the decrease of the mechanical Q value remains within several%.

The curves AMB and BNC are defined as vibrating nodes for convenience. That is, a substantially U-shaped tuning fork crystal blank 3
4 represents a line near the boundary between the vibrating part and the non-vibrating part. That is, when two substantially U-shaped tuning fork-shaped quartz blanks are joined by a connector having a certain area so as to include the same, bending vibration of one substantially U-shaped tuning fork-shaped quartz blank is performed well, and one substantially U-shaped tuning fork-shaped quartz blank is performed. A vibrating node is a portion where the bending vibration of the U-shaped tuning fork crystal blank is easily transmitted to the other approximately U-shaped tuning fork crystal blank.

6 (b) and 6 (c) show the vibration state in the X mode by dotted lines, and the side surface of the substantially U-shaped tuning fork crystal blank vibrates to the lower side as compared to the front and back surfaces. It is shown that. Depending on the dimensions of the vibrating arm and the support, if the support is sufficiently large, point M is approximately at the midpoint. The N point is at 80% to 90% of the support. If the coupling is performed in the oblique line on the symmetry axis of the tuning fork passing through the point M, the resonance Q value of the substantially U-shaped tuning fork crystal blank serving as the driving side tuning fork is small, but the substantially U-shaped tuning fork crystal serving as the detection side tuning fork is reduced. The transmission of vibration energy to the blank is very poor.

Therefore, if coupling is performed with a connector having a certain area including the vibrating node formed by the curve AMB, effective vibration can be transmitted and received. For example, they may be connected by a columnar connector having a rectangular PQRS centered at the point M (see FIG. 6B) as an adhesive area. The size of the area of the rectangular PQRS is a matter of design in consideration of the size of the support.

FIGS. 7 and 8 show one experimental example showing the degree of reduction of the mechanical Q value with respect to the pinpoint support position (x). Fig. 7 shows the dimensions and cut axis of the sample of the substantially U-shaped tuning fork crystal blank used in the experiment.
(A) and (b) show. In FIGS. 7A and 7B,
Dimensions z ₁ is 95 mm, z ₂ is 25 mm, z ₃ is 70 mm, z ₄
Is 5mm, z ₅ is 15mm. With respect to the substantially U-shaped tuning fork-shaped quartz blanks shown in FIGS. 7A and 7B, X-mode vibration is caused, and the pinpoint support positions are set on the h line, the g line,
The degree of reduction of the mechanical Q value was measured by moving on the h 'line and the i line. FIG. 8 shows the experimental results.
The vertical axis of the experimental results shown in FIG. 8 cannot support the bottom (x = 0) of the substantially U-shaped tuning fork-shaped quartz blank, so that the vertical axis was standardized using data of x = 2 mm. In FIG. 8, the solid line indicates the characteristic on the g line,
The broken lines indicate the characteristics on the h line and the h 'line, and the alternate long and short dash line indicates the characteristics on the i line. From this figure, it can be seen that the side of the vibrating arm and the supporting portion of the substantially U-shaped tuning fork crystal blank is affected by the pinpoint support far below the front and back surfaces.

On h and h ', it can be seen that the mechanical Q value is not affected even if the supporting point is considerably close to the vibrating arm. The operating principle of the angular velocity sensor configured as described above will be described below. FIG. 9A is a diagram illustrating the principle of the angular velocity sensor of the present invention. In FIG. 9A, rotation of the angular velocity vector ω is applied around the Y axis in a state in which the two mass points m and m are flexurally vibrated with the velocity vector v in the ± X axis direction that is plane symmetric with respect to the YZ axis plane. Then, a Coriolis force F expressed by an outer product of 2 mω × v is generated at these mass points m and m.

Since the Coriolis force F is perpendicular to the plane defined by the vectors ω and v in the right coordinate direction, the applied angular velocity vector ω can be directly detected by detecting the generated Coriolis force F. The magnitude of the Coriolis force F is as follows: Assuming that the displacement of the mass point m is d = AsinΩt, the velocity | v | is | V | = dd / dt = AΩcosΩt. = 2 mAΩ | ω |.

Here, assuming that the output signal of the angular velocity sensor, that is, the output signal from the detection-side tuning fork is A, the output signal A can be expressed as follows. A = B × C × | F | where B is a constant of the piezoelectric material, and C is a constant related to the shape size. Therefore, when an input angular velocity ω is given, the output signal A obtained from the detection-side tuning fork is expressed as follows: A = 2 × B × C × m × v × | ω | × v = D, A = D × | ω |, and the output signal A obtained from the detection-side tuning fork is proportional to the input angular velocity | ω |, and the input angular velocity | ω | Will be understood.

Here, FIG. 9B is a view showing the principle of operation of the crystal blank 34 which is a main part of the present invention, and corresponds to the principle diagram of FIG. 9A. In FIG. 9B, assuming that the vibrating arms 35A and 35B perform resonance bending vibration at + V and -V speeds in the X-axis direction on the YZ symmetry plane passing through the Y-axis, the direction in which the Y-axis of the quartz blank 34 rotates. When the angular velocity ω is applied to each of the vibrating arms 35A and 35
A Coriolis force F is generated at B.

The operation of the angular velocity sensor according to the first embodiment of the present invention will be described below. FIG. 10 is a plan view of the angular velocity sensor for explaining the operation when viewed from the Y'-axis direction. This angular velocity sensor mainly operates as follows. The driving electrodes 36a to 36d and 37a to 3d of the vibrating arms 24 and 25 using a vibration driving means (not shown) so that the driving side tuning fork 21 maintains the driving vibration in the X-axis direction.
7d, the alternating voltage is applied to the vibrating arms 24, 2 as described above.
When bending vibration of 5 occurs, a vibration in the Z-axis direction is generated by Coriolis force, and the vibration propagates to the detection-side tuning fork 26. The detection-side tuning fork 26 vibrates in the X-axis direction due to a vibration component propagated through the connector 31 to the detection-side tuning fork 26. On the other hand, the electric signal of the X-mode vibration component of the detection-side tuning fork 26, that is,
Detection electrodes 40a to 40d, 41a to 41d provided on the surfaces of vibrating arms 29, 30 of detection-side tuning fork 26 for applying the Coriolis force
As described above, the AC signal is extracted by the signal detecting means (not shown) as described above, whereby an angular velocity signal corresponding to the rotational angular velocity of the driving tuning fork 21 and the detection tuning fork 26 can be obtained. In addition, the following operation is partially performed. As described above, the AC voltage is applied to the driving electrodes 36a to 36d and 37a to 37d of the vibrating arms 24 and 25 by using a vibration driving means (not shown) so that the driving side tuning fork 21 maintains the driving vibration in the X-axis direction. When the vibrating arms 24 and 25 are bent and vibrated by adding
The detection-side tuning fork 26 vibrates in the X-axis direction due to a vibration component propagated through the connector 31 to the detection-side tuning fork 26. On the other hand, the electric signal of the X-mode vibration component in the direction perpendicular to the vibration direction (Z 'axis direction) of the detection-side tuning fork 26, that is, the Coriolis force is applied to the surface of the vibration arms 29 and 30 of the detection-side tuning fork 26. As described above, the AC signal is detected from the detection electrodes 40a to 40d and 41a to 41d provided in the signal detection means (not shown).
Thus, an angular velocity signal corresponding to the rotational angular velocity of the drive-side tuning fork 21 and the detection-side tuning fork 26 is obtained.

According to the angular velocity sensor of this embodiment, the vibrating arms 24 and 25, which are not the bonding type as in the conventional example, are used as the drive-side tuning fork 21 and the detection-side tuning fork 26;
Since a substantially U-shaped tuning-fork type crystal blank in which the 29, 30 and the support portions 25, 28 are integrated respectively is used, the temperature characteristics are excellent over a wide temperature range, and various variations are small and the angular velocity can be detected with high accuracy. Can be.

The resonance frequencies of the bending vibrations of the opposite sides of the one and the other vibrating arms 24 and 25 of the driving-side tuning fork 21 displaced in the X-axis direction and the bending of the detection-side tuning fork 26 in the X-axis direction are opposite to each other. The resonance frequencies of the bending vibrations are substantially equal to the resonance frequency of the vibration, and are displaced in the X-axis direction of the driving-side tuning fork 21, and the Z′-axis direction of one and the other vibrating arms 29 and 30 of the detection-side tuning fork 26. When the drive-side tuning fork 21 is driven by resonance, the detection-side tuning fork 26 is displaced in the X-axis direction from the opposite-phase bending vibration displaced in the X-axis direction. Bending vibrations of opposite phases in the X-axis direction generated and propagated in one and the other vibrating arms 29, 30 of the detection-side tuning fork 26 by the Coriolis force based on the rotational angular velocity about the Y 'axis can be increased, and Z'. Together displaced in a direction can be reduced flexural vibration of the reverse phase. As a result, it is possible to effectively detect the AC voltage generated by the opposite-phase bending vibrations in the X-axis direction while suppressing the influence of the AC voltage generated by the opposite-phase bending vibrations displaced in the Z′-axis direction, and to accurately detect the AC voltages. It is possible to detect the rotational angular velocity around the Y 'axis.

Further, both end surfaces of the connector 31 are connected to the drive-side tuning fork 2.
1 and the vibrating nodes generated in the support portions 23 and 28 of the detection-side tuning fork 26 are partially adhered to the surface including the vibration nodes. It is possible to transmit to the detection-side tuning fork 26 with the maximum mechanical transmission efficiency without lowering the mechanical Q value of the driving-side tuning fork 21, and the driving-side tuning fork 21 and the detection-side tuning fork 26
Can be easily integrated with the connector 31 and the manufacture is easy.

Here, the characteristics and effects of the above embodiment will be described in comparison with the conventional example. According to the above-described embodiment of the present invention, the drive-side tuning fork 21 and the detection-side tuning fork 26, each of which is formed of a substantially U-shaped tuning fork-shaped crystal unit, are integrated by the connector 31 so as to face each other in parallel. High resonance sharpness (mechanical Q value), high angular velocity detection sensitivity, low thermal expansion coefficient, stable drive frequency, and as a result, the phase shift change of synchronous rectification in the above-described sensor signal processing And a part of the drive signal component on the drive side is not mixed into the detection section as an unnecessary signal component, and as a result, the drift stability can be obtained as excellent as 1/10 of the conventional one. Was.

FIG. 11 is a perspective view of an angular velocity sensor according to a second embodiment of the present invention. FIG. 1A is a perspective view in an assembled state, and FIG. 1B is a perspective view in an exploded state. In this angular velocity sensor, as shown in FIG. 11, the connector 31A of the prism-shaped block formed of quartz and the vibrating nodes of both the support portions of the drive-side tuning fork 21 and the detection-side tuning fork 26 are provided as shown in FIG.
8, and is fixed to a certain rectangular area PQRS by bonding, with the center at approximately the midpoint M of FIG. The fixed portion on the back surface of the detection-side tuning fork 26 is not visible in FIG. 11, but is fixed at the same position as the driving-side tuning fork 21.

The angular velocity sensor of this embodiment uses a prismatic connector 31A instead of the columnar connector of FIG. 1, and the other configuration is the same as that of FIG. The effect of this embodiment is the same as that of the first embodiment. FIG. 12 is a perspective view of an angular velocity sensor according to a third embodiment of the present invention. FIG. 1A is a perspective view of an assembled state, and FIG.
FIG. 4 is a perspective view of the disassembled state.

In the angular velocity sensor of this embodiment, rectangular (or circular) through holes 23a, 28a having a certain area including a vibrating node are formed in the support portions 23, 28 of the drive-side tuning fork 21 and the detection-side tuning fork 26, for example, by etching. This is provided by bonding a rectangular (or circular) connector 31 in a state of being inserted into the through holes 23a and 28a. Other configurations are the same as those of the embodiment of FIG.

In this case, the coupling is performed on the surface including the vibrating nodes of the support portions 23 and 28 of the driving-side tuning fork 21 and the detection-side tuning fork 26 by etching or the like in the front and back directions (thickness direction) of the tuning fork. PQRS), 28a (P'Q '
R ′S ′) are provided, and the connector 31A of the prismatic block is inserted and bonded. In this embodiment, both ends of the connector 31 are connected to the support portions 2 of the drive-side tuning fork 21 and the detection-side tuning fork 26.
Through holes 23 partially including vibrating nodes generated in 3, 28
a, 28a, so that the bending vibrations of opposite phases displaced in the Z′-axis direction of the driving-side tuning fork 21 can be performed without lowering the mechanical Q value of the driving-side tuning fork 21. The drive fork 21 and the coupling fork 26 can be transmitted to the detection fork 26 with the maximum mechanical transmission efficiency.
Are firmly integrated with the connector 31 and have excellent vibration resistance. Other effects are similar to those of the first embodiment.

In each of the above-described embodiments, the X on the driving-side tuning fork is used.
The resonance frequencies of the bending vibrations of the opposite phases displaced in the axial direction are substantially equal to the resonance frequencies of the bending vibrations of the opposite phases in the X-axis direction of the tuning fork on the detection side, and are opposite to each other displaced in the X-axis direction of the tuning fork on the driving side. The vibrating arm of the drive-side tuning fork and the detecting side have different resonance frequencies of the phase bending vibration and the resonant frequencies of the opposite-phase bending vibrations displaced in the Z′-axis direction of one and the other vibrating arms of the detecting-side tuning fork. The vibrating arm of the tuning fork was set to have a different shape and size, but instead of this, the resonance frequency of the opposite-phase bending vibration displaced in the X-axis direction of the driving-side tuning fork and the mutual resonance frequency of the detecting-side tuning fork in the X-axis direction were changed. The drive-side tuning fork is driven so that the resonance frequency of the opposite-phase bending vibration and the resonance frequency of the opposite-phase bending vibration displaced in the Z'-axis direction of one and the other vibrating arms of the detection-side tuning fork are different from each other. Make sure that the vibrating arm is It may be set to that geometry. In this case, as an example of the size of the vibrating arm of the detection-side tuning fork, the length (L) was 10 mm, the thickness (t) was 3 mm, and the width (W) was 2.5 mm. The dimensions of the vibrating arm of the drive-side tuning fork are the same as those described above.

With this configuration, the resonance frequency of the bending vibration of the opposite phase displaced in the X-axis direction of the driving tuning fork 21 and the resonance frequency of the bending vibration of the opposite phase in the X-axis direction of the detection tuning fork 26 are detected. Since the resonance frequencies of the flexural vibrations of one and the other vibrating arms of the side tuning fork 26 which are displaced in the Z 'axis direction in the Z'-axis direction are separated from each other and are different from each other, detection is performed when the driving side tuning fork is driven in resonance. In the side tuning fork 26,
X generated on one and the other vibrating arms 24 and 25 of the drive-side tuning fork 21 by the bending vibration of the opposite phases displaced in the X-axis direction and the Coriolis force based on the rotational angular velocity about the Y 'axis.
With respect to bending vibrations having opposite phases in the axial direction, bending vibrations having opposite phases displaced in the Z′-axis direction can be efficiently extracted.
As a result, it is possible to effectively detect the AC voltage generated by the opposite-phase bending vibrations in the X-axis direction while suppressing the influence of the AC voltage generated by the opposite-phase bending vibrations displaced in the Z′-axis direction, and to accurately detect the AC voltages. It is possible to detect the rotational angular velocity around the Y 'axis. Other points are the same as those of the above-described embodiments.

In the embodiment shown in FIG.
The resonance frequencies of the bending vibrations of the opposite phases displaced in the axial direction are substantially equal to the resonance frequencies of the bending vibrations of the opposite phases in the X-axis direction of the tuning fork on the detection side, and are opposite to each other displaced in the X-axis direction of the tuning fork on the driving side. The vibrating arm of the drive-side tuning fork and the detecting side have different resonance frequencies of the phase bending vibration and the resonant frequencies of the opposite-phase bending vibrations displaced in the Z′-axis direction of one and the other vibrating arms of the detecting-side tuning fork. An embodiment in a state where the vibrating arm of the tuning fork is set to a different shape and size is shown. In the embodiment shown in FIG. 12, the resonance frequency of the opposite-phase bending vibration of the drive-side tuning fork displaced in the X-axis direction, the resonance frequency of the opposite-phase bending vibration of the detection-side tuning fork in the X-axis direction, and the detection-side tuning fork are different. The vibrating arm of the drive-side tuning fork and the vibrating arm of the detection-side tuning fork are different from each other so that the resonance frequencies of the opposite-phase bending vibrations displaced in the Z′-axis direction of one and the other vibrating arms are different from each other. An example in a state where the shape and dimensions are set is shown.

It is to be noted that even if the lower bottom portions of the support portions are connected to each other via a connector instead of the vibrating nodes in the support portions of the drive side tuning fork and the detection side tuning fork, vibration is effective from the drive side tuning fork to the detection side tuning fork. , And such a configuration is also included as an example. In other words, any part of the support portion may be connected as long as it transmits a part of the vibration energy without decreasing the mechanical vibration sharpness of the tuning fork vibration. In addition, the bonding is performed at one place, but it is obvious that the bonding may be performed at two or more places by using two or more connectors.

The electrode structures of the drive-side tuning fork 21 and the detection-side tuning fork 26 are not limited to those shown in the above-described embodiments, but may be variously changed. In other words, it is necessary to detect bending vibration and Coriolis signal components. It is something that can be done. For example, the detection electrodes may be four electrodes formed so as to straddle the four ridges of the vibrating arm, or may be two electrodes circumferentially divided on both side surfaces of the vibrating arm.

Also, by maintaining the above two types of resonance frequency conditions and utilizing the difference in Young's modulus due to the difference in crystal axis of quartz, the vibrating arms 24 and 25 of the drive-side tuning fork 21 and the detection-side tuning fork 26 The vibrating arms 29 and 30 can have the same dimensions and a square cross section. As described above, when the drive-side tuning fork 21 and the detection-side tuning fork 26 have exactly the same shape,
Since the shape of both electrodes 22 and 27 is the same,
Assembly is simple and cost reduction can be achieved.

In the above embodiment, the crystal axes X, Y, Z
New crystal axis X rotated about 1 to 3 degrees around the X axis of
A crystal blank cut out in the X, Y 'plane with the Y' axis direction of Y ', Z' as the longitudinal direction was used.
It is also possible to use a quartz blank cut out with the Y-axis direction of Y and Z taken as the longitudinal direction. Therefore, the expression of “new crystal axes X, Y ′, Z ′ rotated around the X axes of the crystal axes X, Y, Z” in the claims indicates that the rotation angle is 0 degree, that is, Axis X, Y, Z and crystal axis X,
The case where Y 'and Z' overlap each other is also included. The rotation angle of the crystal axis may be other than 1 to 3 degrees.

[0068]

As described above, according to the present invention, it is possible to obtain a stable angular velocity sensor in which unnecessary signal components are reduced, and a characteristic change is extremely small in a wide temperature range and abrupt temperature change. Can be. Further, if the drive-side tuning fork and the detection-side tuning fork are fixed via a block connector having a certain area partially including a vibration node generated in the support portion, the mechanical Q value of the tuning-fork vibration and the drive-side tuning fork can be obtained. The efficiency of mechanical transmission from the to the detection-side tuning fork can be maximized.

Therefore, the mechanical transmission loss at the time of coupling both tuning forks can be remarkably improved, and the sensitivity of angular velocity detection by Coriolis force can be improved. And since it is a structure with a simple structure, cost reduction can be achieved,
Great industrial value. Hereinafter, effects of each claim will be described. According to the angular velocity sensor according to the first aspect, a substantially U-shaped tuning fork-shaped quartz blank in which a vibrating arm and a supporting portion, which are not a bonding type as in the conventional example, are integrally used as the driving-side tuning fork and the detection-side tuning fork, respectively. Therefore, the angular velocity can be detected with high accuracy over a wide temperature range, with little variation, and with high accuracy.

According to the angular velocity sensor of the second aspect, the resonance frequency of the bending vibration of the opposite phase displaces in the X-axis direction of the driving-side tuning fork and the resonance of the bending vibration of the opposite phase in the X-axis direction of the detection-side tuning fork. Frequency is almost equal and X of the drive side tuning fork
Since the resonance frequency of the opposite-phase bending vibration displaced in the axial direction is different from the resonance frequency of the opposite-phase bending vibration displaced in the Z′-axis direction of one and the other vibrating arms of the detection-side tuning fork, When the drive-side tuning fork is driven by resonance,
In the detection-side tuning fork, the Z-axis direction generated in one and the other vibrating arms of the driving-side tuning fork by the Coriolis force based on the bending vibration of opposite phases displaced in the Z 'axis direction and the rotational angular velocity around the Y' axis. Bending vibrations of opposite phases can be efficiently extracted, and bending vibrations of opposite phases displaced in the X-axis direction can be reduced. As a result, it is possible to effectively detect the AC voltage caused by the opposite-phase bending vibrations in the Z′-axis direction while suppressing the influence of the AC voltage caused by the opposite-phase bending vibrations displaced in the X-axis direction, and with high accuracy. It is possible to detect the rotational angular velocity around the Y 'axis.

According to the angular velocity sensor of the third aspect, the resonance frequency of the opposite-phase bending vibration of the drive-side tuning fork displaced in the X-axis direction and the resonance of the opposite-phase bending vibration of the detection-side tuning fork in the X-axis direction. Since the frequency and the resonance frequencies of the opposite-phase bending vibrations displaced in the Z′-axis direction of the one and the other vibrating arms of the detection-side tuning fork are separated from each other and different, when the driving-side tuning fork is driven by resonance, , On the detection side tuning fork,
Opposite-phase bending vibrations displaced in the Z'-axis direction and anti-phase bending vibrations in the X-axis direction generated on one and the other vibrating arms of the detection-side tuning fork due to Coriolis force based on the rotational angular velocity around the Y 'axis. In contrast, bending vibrations of opposite phases displaced in the Z'-axis direction can be prevented from becoming extremely large. As a result, it is possible to effectively detect the AC voltage generated by the opposite-phase bending vibrations in the X-axis direction while suppressing the influence of the AC voltage generated by the opposite-phase bending vibrations displaced in the Z′-axis direction, and to accurately detect the AC voltages. It is possible to detect the rotational angular velocity around the Y 'axis.

According to the angular velocity sensor of the fourth aspect, since the electrodes of the detection-side tuning fork are formed only on the front and back surfaces of the pair of vibrating arms, the electrodes are easily formed and the manufacture is easy. . According to the angular velocity sensor according to the fifth aspect, the opposite-phase bending vibrations displaced in the X-axis direction of the drive-side tuning fork are detected at the maximum mechanical transmission efficiency without lowering the mechanical Q value of the drive-side tuning fork. The transmission to the side tuning fork can be performed, and the driving side tuning fork and the coupling side tuning fork can be easily integrated by a connector, which facilitates manufacture.

According to the angular velocity sensor according to the fifth aspect, the bending vibrations of opposite phases displaced in the X-axis direction of the driving-side tuning fork can be transmitted to the maximum mechanical strength without lowering the mechanical Q value of the driving-side tuning fork. In addition to being able to efficiently transmit to the detection-side tuning fork, the driving-side tuning fork and the coupling-side tuning fork are firmly integrated with a connector, and have excellent vibration resistance.

[Brief description of the drawings]

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

FIG. 2 is a schematic view showing a cutting direction of a substantially U-shaped tuning fork crystal blank.

FIG. 3 is a schematic view showing a cutting direction of a substantially U-shaped tuning fork-shaped crystal blank.

FIG. 4 is a schematic diagram showing a state of a drive electrode provided on a drive-side tuning fork and a detection electrode provided on a detection-side tuning fork.

FIG. 5 is a schematic view showing pinpoint support positions of a substantially U-shaped tuning fork-shaped quartz blank.

FIG. 6 is a schematic view of a substantially U-shaped tuning fork-shaped crystal blank for explaining a vibrating node.

FIG. 7 is a schematic diagram showing dimensions and cut axes of a sample of a substantially U-shaped tuning fork-shaped quartz blank.

FIG. 8 is a characteristic diagram showing a difference in mechanical Q value due to a difference in a pinpoint support position of the angular velocity sensor of the present invention.

FIG. 9 is a schematic diagram illustrating the principle of angular velocity detection in the angular velocity sensor according to the first embodiment of the present invention.

FIG. 10 is a schematic diagram showing an operation of detecting an angular velocity in the angular velocity sensor according to the first embodiment of the present invention.

FIG. 11 is a perspective view showing an angular velocity sensor according to a second embodiment of the present invention.

FIG. 12 is a perspective view showing an angular velocity sensor according to a third embodiment of the present invention.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Drive side tuning fork 22 Electrode 23 Support part 24 One vibrating arm 25 The other vibrating arm 26 Detection side tuning fork 27 Electrode 28 Support part 29 One vibrating arm 30 The other vibrating arm 31 Coupler 32 Joining part including vibrating node 33 Vibration Joints including nodes 36a to 36d Driving electrodes 37a to 37d Driving electrodes 38, 39 Common lines 40a to 40d Detection electrodes 41a to 41d Detection electrodes 42, 43 Common lines 31A Connectors 23a, 28a Through holes 23b, 28b Through holes 50a to 50d Detection electrodes 51a to 51d Detection electrodes

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Toshihiko Ichise 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Atsushi Otomo 1275-2 Kamihirose, Sayama City, Saitama Prefecture Nippon Dempa Kogyo Co., Ltd.Sayama Office (72) Inventor Jira Ota 12275-2 Kamihirose, Sayama City, Saitama Prefecture Nippon Dempa Industry Co., Ltd. 72) Inventor Koichiro Ota 12275-2 Kamihirose, Sayama City, Saitama Prefecture Nippon Denpa Kogyo Co., Ltd., Sayama Plant (72) Inventor Minoru Ishihara 125-2 Kamihirose, Sayama City, Saitama Prefecture Nippon Dempa Industry Co., Ltd., Sayama Plant (56) References JP-A-7-260490 (JP, A) JP-A-7-260491 (JP, A) JP-A-7-260488 (JP, A) JP-A-4-324311 (JP, A) JP-A-60-73414 (JP, A) JP-A-3-291517 (JP, A) JP-A-3-113310 (JP, A) JP-A-64-16911 ( JP, A) JP-A-60-196634 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01C 19/56 G01P 3/00 G01P 9/04

Claims (6)

(57) [Claims] 1. A new rectangular crystal axis X, Y ', Z' rotated around the X axis of X, Y, Z is cut out in the X, Y 'plane with the Y' axis direction as a longitudinal direction. A first U-shaped tuning fork-shaped quartz blank having a shape in which one and the other symmetric vibrating arms of a cross section are connected in parallel and integrally by a support portion, and the first and the other vibrating arms are provided with electrodes on the peripheral surface thereof. And a new crystal axis X, Y ', Z' rotated around the X axis of the crystal axes X, Y, Z, with the Y 'axis direction as the longitudinal direction, and Y',
An electrode is formed on the peripheral surface of the one and other vibrating arms of a substantially U-shaped tuning fork-shaped crystal blank having a shape in which one and the other symmetrical vibrating arms of a rectangular cross section are cut out in the Z 'plane and connected in parallel and integrally by a support portion. And a second tuning-fork type crystal unit having a first tuning-fork type crystal unit fixed to the supporting portion via a coupler in a state where the second tuning-fork type crystal unit is parallel to and opposed to each other. A drive-side tuning fork that generates opposite-phase bending vibrations that are displaced in the X-axis direction of one and the other vibrating arms by applying an AC voltage via an electrode; Is generated by Coriolis force based on bending vibrations of opposite phases, which are displaced in the Z′-axis direction and propagate in the Z′-axis direction, propagated from the first tuning-fork type quartz resonator via the connector, and the rotational angular velocity around the Y′-axis. One and the other swing arm An angular velocity sensor, characterized in that mutually was detected side tuning fork for angular velocity detection for detecting via the electrodes an AC voltage generated by the flexural vibration of the reverse phase in the X-axis direction. 2. The drive-side tuning fork displaces in the X-axis direction and the resonance frequency of the opposite-phase bending vibrations is substantially equal to the resonance frequency of the detection-side tuning fork and the opposite-phase bending vibrations in the X-axis direction, and The resonance frequency of the opposite-phase bending vibration displaced in the X-axis direction of the side tuning fork is different from the resonance frequency of the opposite-phase bending vibration displaced in the Z′-axis direction of one and the other vibrating arms of the detection-side tuning fork. The angular velocity sensor according to claim 1, wherein the vibrating arm of the drive-side tuning fork and the vibrating arm of the detection-side tuning fork are set to have different shapes and sizes. 3. A resonance frequency of a bending vibration of the opposite phase displaced in the X-axis direction of the driving-side tuning fork, a resonance frequency of a bending vibration of the opposite phase in the X-axis direction of the detection-side tuning fork, and one of the detection-side tuning forks and The vibrating arm of the driving-side tuning fork and the vibrating arm of the detecting-side tuning fork have different shapes so that the resonance frequencies of the opposite-phase bending vibrations displaced in the Z'-axis direction of the other vibrating arm are different from each other. 2. The angular velocity sensor according to claim 1, wherein the angular velocity is set to a dimension. 4. Electrodes disposed on the peripheral surface of one and the other vibrating arms of the drive-side tuning fork are provided on the four peripheral surfaces on the front and back surfaces and on both sides of the one and the other vibrating arms when viewed in the Z 'axis direction.
Are provided in a state divided into four in the circumferential direction at two ridge lines, and the front and back electrodes of the one vibrating arm and the both side electrodes of the other vibrating arm are connected in common, and the surface of the other vibrating arm is connected. The back electrode and the electrodes on both sides of the one vibrating arm are connected in common, and the electrodes disposed on the peripheral surface of one and the other vibrating arms of the detection-side tuning fork are arranged so that the one and the other of the other vibrating arms are viewed in the X-axis direction. The vibrating arm is provided on each of the four peripheral surfaces on the front and back and on both sides in a state of being divided into four in the circumferential direction at four ridges, and the front and rear electrodes of the one vibrating arm and the both side electrodes of the other vibrating arm are provided. 2. The angular velocity sensor according to claim 1, wherein the front and back electrodes of the other vibrating arm and the both side electrodes of the one vibrating arm are connected in common. 5. The connector has a columnar shape with both end faces having a certain area, and both end faces are bonded to a surface partially including a vibrating node generated in a supporting portion of the driving-side tuning fork and the detection-side tuning fork. The angular velocity sensor according to claim 1, wherein 6. The drive-side tuning fork and the detection-side tuning fork each have a through-hole having an area partially including a vibrating node generated in the support portion, and the connector has a columnar shape. 2. The angular velocity sensor according to claim 1, wherein the sensor is attached to a supporting portion of the driving-side tuning fork and the detection-side tuning fork while being inserted through the through hole.