JP2002257549A - Tuning fork vibrator, angular velocity sensor provided with tuning fork vibrator, and method of manufacturing angular velocity sensor - Google Patents

Abstract

(57) [Summary] To provide a tuning fork vibrator, an angular velocity sensor, and a method of manufacturing an angular velocity sensor with higher angular velocity detection accuracy compared to the related art. SOLUTION: The piezoelectric device has a base 22 on which protruding fixing portions 22a and 22b are formed, an excitation shaft 23 and a detection shaft 24 which are erected from the base 22 and arranged to face each other, and are constituted by piezoelectric elements. In the tuning fork vibrator 21, the excitation axis 23 is perpendicularly polarized in plane so that the excitation electrodes 25 a and 25 d and the excitation electrodes 25 b and 25 c are in opposite polarization directions, and the detection axis 24 is connected to the detection electrodes 26 a at both ends. 26f and detection electrode 26
c and 26d, the surfaces are perpendicularly polarized so that the polarization directions are opposite to each other, and the central detection electrodes 26b and 26d
e, the electrodes are in-plane polarized so as to have zero potential between the detection electrodes 26a, 26f, 26c, and 26d at both ends.
b, 25c and the detection electrodes 26c, 26d have the same polarization direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tuning fork vibrator, an angular velocity sensor, and a method of manufacturing an angular velocity sensor, and more particularly, to a posture control and navigation system of a moving body such as a vehicle, an aircraft, and a ship. The present invention relates to a tuning fork vibrator, an angular velocity sensor, and a method for manufacturing an angular velocity sensor.

[0002]

2. Description of the Related Art In recent years, as information has become more sophisticated, sensors capable of obtaining more accurate information have been demanded, and sensors have been developed in various fields. Among them, the angular velocity sensor is a sensor with high needs, and in particular, the tuning fork vibration type angular velocity sensor can be manufactured in a small size and light weight, so that it is applied in a wide range of fields.

Conventionally, as a tuning fork vibration type angular velocity sensor,
For example, an angular velocity sensor as shown in FIG. 24 is known.

First, the configuration of the angular velocity sensor will be described.

In FIG. 24, a base 910 of the angular velocity sensor 900 is provided with a U-shaped metal vibration plate 940 via a fixed shaft 920. An excitation piezoelectric element 951 is provided on one surface of the metal vibration plate 940.
A monitor piezoelectric element 952 is provided on the other surface, and the piezoelectric elements 951 and 952 are fixed to the metal vibration plate 940 with an adhesive.

The metal diaphragm 940 includes a pair of metal plates 941 and 942, and a surface of the metal diaphragm 940 and the metal plate 94.
1, 942 are provided so as to be orthogonal to each other. The metal plates 941 and 942 are provided with Coriolis detecting piezoelectric elements 953 and 954, respectively, such that the surfaces of the piezoelectric elements 951 and 952 and the surfaces of the Coriolis detecting piezoelectric elements 953 and 954 are orthogonal to each other. , 954 are fixed to the metal plates 941, 942 by an adhesive.

The metal vibration plate 940, the metal plates 941 and 942, and the piezoelectric elements 951 to 954 form a tuning fork vibrator 930.

The piezoelectric elements 951 to 954 are connected to lead pins 971 to 9 by lead wires 961 to 964, respectively.
The lead pins 971 to 974 are electrically insulated from the base 910 via an insulator 980 such as glass.

Next, the operation of each speed sensor will be described.

In FIG. 24 (a), the excitation piezoelectric element 9
When a voltage is applied to 51, the tuning fork vibrator 930 turns
The tuning fork is excited in the direction of 0a. The excitation piezoelectric element 9
The voltage applied to 51 is controlled based on the excitation frequency and amplitude monitored by the monitoring piezoelectric element 952 so that the tuning fork vibrator 930 is always excited at a constant frequency and amplitude.

At this time, as shown in FIG. 24 (b), when the rotational angular velocity ω in the direction of the arrow 900a is applied to the detection axis 901 of the angular velocity sensor 900, the arrow 9 excited by the tuning fork is turned on.
Coriolis force F generated in a direction perpendicular to the direction of 30a
C causes the metal plates 941 and 942 to bend in opposite directions (directions of arrows 941a and 942a).

Here, the Coriolis force FC expands in one of the Coriolis detecting piezoelectric elements 953 and 954 and generates a distortion in the other direction of contraction in the other direction. Therefore, the detection voltage of the Coriolis detecting piezoelectric elements 953 and 954 is read. Lines 963, 9
64 and can be taken out from the lead pins 973 and 974 as differential outputs. The Coriolis force FC is
Using the rotational angular velocity ω, the mass m of the tuning fork vibrator 930, and the excitation speed V of the tuning fork vibrator 930, the following expression can be used. FC = 2mVω Equation (1)

Accordingly, the rotational angular velocity ω, that is, the angular velocity, can be obtained by using the angular velocity sensor 900.

[0014]

However, the conventional angular velocity sensor described above has a problem that the angular velocity detection accuracy cannot be improved.

More specifically, the angular velocity sensor 90
0, a rotational angular velocity ω is generated and the tuning fork vibrator 93
When the Coriolis force FC is applied to the fixed shaft 920, a rotational moment M generated by bending the tuning fork vibrator 930 in the directions of arrows 941a and 942a in FIG. 24B is applied to the fixed shaft 920. 910 and metal diaphragm 9
The degree of fixing to 40 has caused a variation in the detection accuracy of the angular velocity. Further, the excitation piezoelectric element 951, the monitor piezoelectric element 952, and the Coriolis detection piezoelectric elements 953, 9
54 is a metal vibration plate 940 and a metal plate 94 by an adhesive.
1 and 942, the variation in adhesion and the temperature characteristics of the adhesive cause the variation in detection accuracy of the angular velocity by the angular velocity sensor 900. Furthermore, the angular velocity sensor 900 also determines variations in the adhesion precision, the precision in fixing the fixed shaft 920 to the base 910 and the tuning fork vibrator 930, and the precision in the assembling processing such as the bending precision of the tuning fork vibrator 930. Was a cause of the variation in the detection accuracy.

Since the leads 961 to 964 are connected to the vibrating metal vibration plate 940 and the metal plates 941 and 942 via the piezoelectric elements 951 to 954, the lead wire 9
The torsion of 61 to 964 has caused a variation in the detection accuracy of the angular velocity by the angular velocity sensor 900.

Further, since the conventional angular velocity sensor is a non-resonant angular velocity sensor, there is a problem that the sensitivity is lower than that of the resonance angular velocity sensor. More specifically, in the angular velocity sensor 900, the excitation direction (arrow 93)
0a) and the Coriolis detection direction (arrows 941a, 941)
2a), the metal diaphragm 940 and the metal plate 94
Since the shapes (thickness and width) of Nos. 1 and 942 do not match, it was difficult to match the resonance frequency Fa during excitation with the resonance frequency Fb during Coriolis detection as shown in FIG.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a tuning fork vibrator, an angular velocity sensor, and a method of manufacturing an angular velocity sensor which have higher angular velocity detection accuracy than the prior art.

[0019]

In order to solve the above-mentioned problems, a tuning fork vibrator of the present invention is provided so as to face a base on which a protruding fixing portion is formed, and stand upright from the base to face each other. First
An excitation axis and a first detection axis, which are composed of a piezoelectric element, and are excited in an in-plane direction where the first excitation axis and the first detection axis are close to and separated from each other;
A tuning fork vibrator for detecting a Coriolis force generated when an angular velocity which is parallel to an excitation axis and a first detection axis and an angular velocity about a center axis opposed to these two axes as a rotation axis is applied as a bending in a direction perpendicular to a plane, A first excitation axis is provided on the front and back sides with two sets of excitation electrodes which are led to the base and are opposed to each other, and the two excitation electrodes are plane-perpendicularly polarized so as to have polarization directions opposite to each other. The detection axis is provided on the front and back surfaces with three sets of detection electrodes led to the base and opposed to each other. Of the three sets of detection electrodes, the detection electrodes at both ends are surface-perpendicularly polarized so as to have polarization directions opposite to each other. In addition, the center detection electrode of the three detection electrodes is in-plane polarized so as to have a zero potential between the detection electrodes at both ends, and the first detection axis side of the two excitation electrodes Of one set of excitation electrodes and three sets of detection electrodes The polarization direction of the pair of sensing electrodes Chi said first excitation axis side has a configuration the same. With this configuration, the tuning fork vibrator is excited in the in-plane direction, and in this excited state, when an angular velocity is applied around the central axis of the tuning fork vibrator, the Coriolis force generated in a direction perpendicular to the excitation direction is perpendicular to the excitation direction. Is detected as the deflection in the direction perpendicular to the plane of the detection axis, the angular velocity can be detected. Further, in this configuration, since the tuning fork vibrator can be integrated with a unimorph, an adhesive unlike the case of forming a bimorph tuning fork vibrator can be eliminated, and the vibration characteristics can be stabilized. The in-plane vibration characteristics can be stabilized by utilizing the characteristics of the tuning fork vibrator. In addition, since the excitation of the tuning fork vibrator is an in-plane tuning fork excitation, the excitation efficiency can be improved, and the excitation shaft has two sides.
By forming successive electrodes, the area of the excitation electrode for in-plane excitation can be increased, so that the excitation efficiency can be improved. In addition, an electrode having zero potential due to in-plane polarization is arranged at the center of the detection axis, and electrodes having potentials in the opposite direction are arranged on both sides due to plane perpendicular polarization. Since it is possible to take out the difference between the electrode and the electrode having the central zero potential, noise can be canceled and the detection sensitivity can be improved.

Further, the angular velocity sensor according to the present invention has a tuning fork vibrator and an arm-like fitting portion for sandwiching a ridge of the projecting fixing portion of the tuning fork vibrator. And a holding member that holds the tuning fork vibrator by fitting the ridge. With this configuration,
The angular velocity sensor of the present invention is provided with a holding member that holds the tuning fork vibrator, and the holding member has an arm-shaped fitting portion that is fitted to the ridge so as to sandwich the ridge of the protruding fixed portion. With this arrangement, when holding the tuning fork vibrator, the arm-shaped fitting portion is deformed to obtain a spring property, and since the line fork is fixed, the tuning fork vibrator can be stably held. In addition, it is possible to reduce the influence of the fixed variation on the detection sensitivity.

Further, in the angular velocity sensor according to the present invention, in the electrode pattern arrangement of the tuning fork vibrator on the base, two excitation electrodes of the first excitation shaft led out to the base include:
The tuning fork vibrator has a configuration arranged only on one side of a central axis. With this configuration, the angular velocity sensor according to the present invention includes two electrode patterns of the excitation axis led to the base,
By arranging it on one side of the center axis of the tuning fork vibrator, the two excitation electrode patterns can be prevented from expanding and contracting the base itself during excitation driving, and the base itself can be prevented from vibrating. Therefore, the detection sensitivity can be improved. Furthermore, since the excitation and detection electrodes are led out to the base, the signal line connection with the circuit board can be performed on the base with less vibration, so that the connection reliability can be improved.

The angular velocity sensor according to the present invention has a configuration in which the holding member has a pin, and the tuning fork vibrator is mounted on the circuit board by fixing the pin to the circuit board. With this configuration, the angular velocity sensor of the present invention can easily mount the holding member directly on the circuit board by soldering or the like, so that the reliability of the mounting of the tuning fork vibration can be increased and the workability of the mounting operation can be improved. Can be improved.

Further, the angular velocity sensor according to the present invention has a configuration in which the holding member has a V-groove in the fitting portion, and is a spring-like V-groove clamper for equalizing stress. With this configuration, the angular velocity sensor according to the present invention can achieve downsizing by forming the holding member into a shape in which the stress is equalized, and can generate a strong clamping force. When the tuning fork vibrator is held (fixed) using such a V-groove holding member, mechanical leakage at the time of excitation becomes stable,
Characteristics can be stabilized.

The angular velocity sensor according to the present invention has a configuration in which the holding member is made of tungsten, phosphor bronze, or stainless steel. With this configuration, the angular velocity sensor of the present invention has a large specific gravity as a holding member, and uses tungsten, phosphor bronze, or stainless steel having a strong spring property to reduce vibration leakage during excitation of the tuning fork vibrator and detection of Coriolis force. At least, the tuning fork vibrator can be stably held by the holding member.

In the angular velocity sensor according to the present invention, as the Coriolis force detecting circuit when the angular velocity is generated, the excitation of the first detection axis can be performed not only by the tuning fork driving from the first excitation axis but also by the first detection axis itself. Is also performed in combination. With this configuration, the angular velocity sensor of the present invention excites the detection axis, not only the subordinate tuning fork drive from the excitation axis but also the drive of the detection axis itself, so that the amplitude can be increased and the detection sensitivity is improved. .

The angular velocity sensor according to the present invention has a configuration in which the tuning fork vibrator is mounted on the circuit board so that the direction of the rotation axis of the tuning fork vibrator and the direction of the yaw rotation axis are the same. I have. With this configuration, the angular velocity sensor according to the present invention can accurately detect the angular velocity of the vehicle or the like during yaw rotation.

Further, the angular velocity sensor according to the present invention is characterized in that a vibrator unit formed by holding the tuning fork vibrator on the holding member and mounting the vibrator on the circuit board is connected to a stem via an under elastic sheet and an upper elastic sheet. The tuning fork vibrator is elastically supported by sandwiching the signal line with a flexible substrate and connecting the signal line with a flexible substrate. With this configuration, the angular velocity sensor of the present invention can make the tuning fork vibrator an elastic support floating from the stem, thereby minimizing the influence of external vibration noise. In addition, it can be made strong against a drop impact.

Further, in the angular velocity sensor according to the present invention, the tuning fork vibrator is disposed to face the first detection axis with the base interposed therebetween, and has a polarization direction and an electrode under the same conditions as the first excitation axis. A second excitation axis, a second detection axis disposed opposite to the first excitation axis with the base interposed therebetween, and having a polarization direction and an electrode under the same conditions as the first detection axis; When the excitation axis and the second excitation axis excite in the in-plane direction, the second excitation axis and the second detection axis are opposite to the excitation direction of the first excitation axis and the first detection axis. In the excited state, the first detection axis and the second detection axis vibrate in opposite directions in a plane perpendicular direction by Coriolis force generated when an angular velocity is applied around the rotation axis in an excited state. ing. With this configuration, the angular velocity sensor of the present invention has an H-shaped structure in which the excitation axis and the detection axis alternately face each other with the tuning fork vibrator sandwiching the base. Can be smaller. In addition, when detecting the vertical direction of the surface, the vertical vibration of the upper and lower two sets of excitation axes and detection axes can be applied in the direction to cancel the moment, and vibration leakage occurs both at the time of excitation and when the Coriolis force is detected. A small number of tuning fork vibrators can be obtained. As a result, the detection sensitivity can be improved, and the excitation can be performed in the in-plane direction such that the opening and closing directions (proximity and separation directions) of the two sets of the excitation axis and the detection axis are opposite to each other. A stable fixing can be performed by reducing (cancelling) the moment at the fixing portion. In addition, the moment generated in the fixed portion can be caused to act in a direction to be canceled by the upper and lower excitation axes and the detection axis due to the surface vertical vibration at the time of detecting the Coriolis force, so that a stable fixing is performed also for the Coriolis force detection. be able to. As a result, the efficiency of both excitation and detection can be improved, and the sensitivity can be improved.

Further, in the angular velocity sensor according to the present invention, the tuning fork vibrator is disposed so as to face the first excitation axis with the base interposed therebetween, and has a polarization direction and an electrode under the same conditions as the first excitation axis. A second excitation axis, a second detection axis disposed opposite to the first detection axis with the base interposed therebetween, and having a polarization direction and an electrode under the same conditions as the first detection axis; When the excitation axis and the second excitation axis excite in the in-plane direction, the second excitation axis and the second detection axis are in the same direction with respect to the excitation direction of the first excitation axis and the first detection axis. In the excited state, the first detection axis and the second detection axis vibrate in the same direction in a direction perpendicular to the plane by Coriolis force generated when an angular velocity is applied around the rotation axis in an excited state. I have. With this configuration, the angular velocity sensor of the present invention has an H-shaped structure in which the excitation axis and the detection axis alternately oppose each other with the tuning fork vibrator interposed therebetween, so that when Coriolis force is generated, two pairs of the excitation axis and the detection axis are used. And the sensitivity can be improved. Further, at the time of in-plane excitation, vibration leakage due to tuning fork vibration can be reduced.

In the method of manufacturing an angular velocity sensor according to the present invention, in manufacturing the tuning fork vibrator, a sheet material made of a piezoelectric element is prepared, and the excitation electrode and the detection electrode are collectively formed on the sheet material by photolithography. After forming an electrode, and then applying a voltage to the excitation electrode and the detection electrode to collectively perform polarization processing in the polarization direction, the tuning fork vibrator is cut out from the sheet material. . With this configuration, the tuning fork vibrator, which is the heart of the angular velocity sensor, can be manufactured by the collective electrode formation, the collective polarization processing, and the collective cutout method, and the cost of the angular velocity sensor can be reduced.

In the method of manufacturing an angular velocity sensor according to the present invention, when a voltage is applied to the excitation electrode and the detection electrode to perform a polarization process collectively in the polarization direction, A configuration is provided in which a polarization process is performed so that the polarization direction of one set of excitation electrodes on the first detection axis side and one of the three detection electrodes on the first excitation axis side are the same. are doing. With this configuration, during the collective polarization processing, by performing the polarization processing so that the polarization directions of the adjacent electrodes of the excitation axis and the detection axis are the same, it is possible to reduce the influence of polarization on the excitation axis and the detection axis. Therefore, depolarization during polarization can be reduced.

Further, in the method of manufacturing an angular velocity sensor according to the present invention, when a voltage is applied to the excitation electrode and the detection electrode and the polarization process is performed collectively in the polarization direction, the back surface of the sheet material is opposed to the opposite direction. In the state where the electrode is connected to GND, a negative polarization voltage is applied to the negative electrode on the front surface of the sheet material to perform surface perpendicular polarization, and then, in the state where the opposite corresponding electrode on the back surface of the sheet material is connected to GND. After applying a positive polarization voltage to the positive electrode on the surface of the sheet material to perform surface perpendicular polarization, the center detection electrode of the three detection electrodes is connected to GN.
D, the positive and negative electrodes on the front and back surfaces of the sheet material are connected to each other, and a positive and negative polarization voltage is applied to the sheet material.
It has a configuration in which both sides of the center detection electrode of the set of detection electrodes are simultaneously in-plane polarized. With this configuration, two plane-perpendicular polarizations and two in-plane polarizations can be performed with three times the number of times of polarization, so that not only the efficiency of polarization can be improved but also the center of the three sets of detection electrodes of the detection axis. This has the advantage that the in-plane polarization on both sides can be performed simultaneously with the detection electrode at zero potential, and the variation in in-plane polarization can be reduced.

Further, in the method of manufacturing an angular velocity sensor according to the present invention, as the plating of the tuning fork vibrator, a low phosphorus type electroless Ni plating or a Ni-B (boron) type electroless Ni plating is applied as a base plating. It has a structure in which combine plating is performed in which bright electric Ni plating is applied on the undercoat. With this configuration, it is possible to achieve both photolithographic formation of the electrode pattern and wire bonding of the aluminum wire.

In the method of manufacturing an angular velocity sensor according to the present invention, the holding member plated with the material is prepared, and the fixing portion of the tuning fork vibrator cut out of the sheet material is fitted to the fitting member of the holding member. After the fitting, the holding member is heated to melt the plating applied to the holding member and fill the gap between the fixing portion and the fitting portion. With this configuration, the holding member can be brought into close contact with the fixing portion, and the tuning fork vibrator can be stably and reliably attached to the holding member.

Further, in the method of manufacturing an angular velocity sensor according to the present invention, the tuning fork is applied by applying an AC voltage to each of the excitation electrodes formed on the excitation shaft of the tuning fork vibrator clamped to the holding member. The vibrator is excited in the in-plane direction, and then the difference between the respective output voltages generated between the detection electrodes at both ends formed on the same plane side of the detection axis and the detection electrode at the center is determined. By monitoring, the presence or absence of kinking vibration of the tuning fork vibrator and the magnitude and direction of kinking when the tuning fork vibrator has kinking vibration are determined. With this configuration, the magnitude and the vibration direction of the unnecessary vibration mode in the direction perpendicular to the surface (as a result, the tuning fork vibrator becomes kinked vibration) mixed despite the in-plane excitation can be easily detected at a stage before assembly. be able to.

Further, according to the method of manufacturing an angular velocity sensor of the present invention, as a result of determining whether or not the tuning fork vibrator has kinking vibration,
In the case where the tuning fork vibrator has a kinking vibration, a bend portion of either the excitation shaft or the detection shaft is chamfered to reduce the kinking vibration of the tuning fork vibrator. With this configuration, unnecessary vibration modes (generated due to minute differences in the shape and dimensions between the excitation axis and the detection axis of the tuning fork vibrator) that are mixed despite in-plane excitation can be easily reduced. It is possible to cause regular in-plane excitation.

Further, in the method of manufacturing an angular velocity sensor according to the present invention, when chamfering a quad portion of the excitation shaft or the detection shaft, the quadrature of the excitation shaft or the detection shaft positioned in a direction in which kinks are directed. One or more chamfered portions are provided to reduce the kinking vibration of the tuning fork vibrator. With this configuration, it is possible to specify the direction of the kinking vibration and the location of the C chamfered corner for correcting the direction.

Further, the method of manufacturing an angular velocity sensor according to the present invention includes a sensor unit comprising the tuning fork vibrator mounted on the circuit board connected by the flexible board via the holding member and combined with a supporter. Detecting and measuring Coriolis output by applying angular velocity with the signal line of the flexible substrate connected to the lead pin formed on the stem while holding it by clamping it with the elastic projection of the under elastic sheet on the stem In addition, a characteristic adjustment is performed by trimming a resistor mounted or formed on the circuit board based on the measurement data detected and measured. With this configuration,
Since the Coriolis output can be measured by applying an angular velocity to the tuning fork vibrator in a state close to the can-sealed state, the measurement data is not so different from the measurement data of the final-shape angular velocity sensor in the can-sealed state. Even if the characteristics are adjusted by trimming in the state, the adjustment accuracy is high, and the yield of the angular velocity sensor can be improved.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

The angular velocity sensor according to the present embodiment is mounted on a posture control and navigation system of a moving body such as a vehicle, an aircraft, and a ship.

First, the structure of the tuning fork vibrator will be described, including the order of assembly.

In FIGS. 1 and 2, the tuning fork vibrator 21 has a base 22 on which protruding fixing portions 22a and 22b are formed.
And an excitation shaft (first excitation shaft) 23 and a detection shaft (first detection shaft) 24 which are erected from the base 22 and arranged to face each other, and are made of piezoelectric ceramics.

On the surface of the excitation shaft 23, two excitation electrodes 25a and 25b are provided.
On the back surface of the device so as to face the excitation electrodes 25a and 26b.
Two excitation electrodes 25 c and 25 d are provided, and these excitation electrodes 25 a to 25 d are led out to the base 22.

Further, three detection electrodes 26a to 26c are provided on the front surface of the detection shaft 24, and three detection electrodes 26d to 26f are provided on the back surface of the detection shaft 24 so as to face the detection electrodes 26a to 26c. The detection electrodes 26 a to 26 f are led out to the base 22.

The polarization directions of the excitation electrodes 25a and 25d and the excitation electrodes 25b and 25c are opposite (arrows 27a and 27d).
7b).
The detection electrodes 26a and 26f on both sides and the detection electrodes 26
The polarization direction is opposite to that of c and 26d (arrows 28a and 28b
), The center detection electrode 26b and the detection electrodes 26a, 26c on both sides are in-plane polarized in the directions of arrows 29a, 29b, and the center detection electrode 26b. 26e and detection electrodes 26d on both sides, 2
6f is opposite to the direction of the arrows 29a and 29b (arrow 29).
(direction of c, 29d).

For this reason, the positive potential after the polarization is
a and 25c and the detection electrodes 26a and 26d, and the negative electrodes are the excitation electrodes 25b and 25d and the detection electrodes 26a and 26d.
f, 26c, and the central detection electrodes 26b, 26e become zero electrodes and are led out to the base 22. Excitation electrodes 25a, 25b and excitation electrodes 25c, 25 led out to the base 22
d is arranged on one side of the central axis 40 of the tuning fork vibrator 21.

The excitation electrodes 25a, 25b formed on the surface of the excitation shaft 23 are connected by wires 30a, 30b via a detection electrode 26b, which is a zero electrode. The electrodes 25c and 25d are connected by a wire 30c. The detection electrode 26d and the detection electrode 26f are connected by a wire 30d, and the excitation electrode 25c and the detection electrode 26d are connected by a wire 30e. The connection by the wires 30d and 30e can be omitted.

Further, independent electrodes 31a to 31d are formed on the front and back surfaces of the fixing portions 22a and 22b, respectively, and these independent electrodes 31a to 31d come into contact with a clamper block (holding member) 32 shown in FIGS. It is supposed to.

The clamper block 32 is made of tungsten, phosphor bronze, stainless steel, or the like, and holds the tuning fork vibrator 21 so as to sandwich the fixing portions 22a and 22b.

That is, the clamper block 32 is provided with a main body 33 on which guide pins 33a to 33d are formed, and V-grooves 34a, 35a formed on the main body 33 and formed on the ridges 22c of the fixing portions 22a, 22b. Arm members (fitting portions) 34, 35 fitted to the fixing portions 22a, 22b so as to hold the main members 33 to 22f. 34, 35 are separated by a slot 36a, 36b. Note that semicircular grooves may be formed at the ends of the arm members 34 and 35 instead of the V grooves.

When the tuning fork vibrator 21 is held by the arm members 34 and 35, the clamper block 32 extends the arm members 3 so that the areas of the slits 36a and 36b are widened.
By deforming the arm members 4 and 35, a spring property can be obtained. However, when the arm members 34 and 35 are deformed, an equal stress design is performed so that each part of the arm members 34 and 35 becomes equal stress. Therefore, the shape is such that stress is not locally concentrated.

The V-groove 34 of the clamper block 32
As shown in FIG. 4 (a), low melting point plating 37 is previously applied to the a and 35a. After the clamper block 32 is attached to the tuning fork vibrator 21, the V-grooves 34a and 35b are removed from FIG. As shown in b), by heating with the heater block 38 and reflowing the low-melting-point plating 37, the fixed portion 22 a generated by the processing accuracy of the tuning fork vibrator 21,
The gap between the ridges 22c to 22f of the base 22b and the V-grooves 34a and 35b is filled with the low melting point plating 37 via the independent electrodes 31a to 31d, and the tuning fork vibrator 21 and the clamper block 3 are filled.
2 is reduced. Further, in the tuning fork vibrator 21, the independent electrodes 31a to 31d may be grounded via the clamper block 32 on which the low melting point plating 37 is applied.

Here, the operation mechanism of the tuning fork vibrator 21 will be described with reference to FIG.

The fixed part 22 is fixed by the clamper block 32.
The tuning fork vibrator 21 to which a and 22b are fixed has an excitation shaft 23.
5A and the tuning fork effect, the excitation shaft 23 and the detection shaft 24 are moved in the in-plane direction (arrow 39) as shown in FIG.
a, 39b and directions of arrows 39c, 39d).

Specifically, when the excitation shaft 23 vibrates in the direction of the arrow 39a, the detection shaft 24 is moved by the arrow 3a due to the tuning fork effect.
9c, and at the next moment, the excitation axis 23 and the detection axis 24 are opposite to the directions of arrows 39a and 39c (arrow 39).
b, 39d), and this operation, that is, the vibration in the in-plane direction where the excitation shaft 23 and the detection shaft 24 approach and separate from each other is repeated.

In such an in-plane excitation state, when a rotational angular velocity Ω around the center axis 40 of the tuning fork vibrator 21 is applied to the tuning fork vibrator 21, the Coriolis force is applied in a direction substantially orthogonal to the excitation direction. 5b, the excitation shaft 23 and the detection shaft 24 generate vibrations in the components in the direction perpendicular to the plane 40a, 40b and 40a ', 40b' as shown in FIGS. 5B and 5C. Then, this vibration component is detected by the detection shaft 24.
The magnitude of the applied angular velocity is measured by detecting with the detection electrodes 26a to 26f formed in the above.

FIG. 6A is a diagram showing a circuit configuration for detecting the excitation and the angular velocity.

In FIG. 6A, the excitation electrodes 25a and 25b formed on the surface of the excitation shaft 23 are connected to one terminal (COMMON line) 42a of the power source 42, and the excitation electrode formed on the back surface. 25c and 25d are connected to the other terminal (DRV line) 42b of the power supply 42, and alternately apply positive and negative voltages from the power supply 42 to the excitation electrodes 25a.
To 25d, the reference numeral 43 of the excitation shaft 23 is obtained.
The right portion surrounded by a and the left portion surrounded by reference numeral 43b alternately expand and contract, and the excitation shaft 23 vibrates in the in-plane direction X. At this time, the detection shaft 24 vibrates in the in-plane direction X by the above-described mechanism due to the tuning fork effect.

The detection electrodes 26a to 26a formed on the detection shaft 24
26c vibrates in the direction perpendicular to the plane caused by the generation of the Coriolis force, and the voltage generated on the detection shaft 24 due to the alternate extension and contraction of the upper portion surrounded by the reference numeral 44a and the lower portion surrounded by the reference numeral 44b of the detection shaft 24. To the detection electrode 26b
Can be taken out from the output terminals 46a, 46b as differential outputs (differential between S ⁻ and S ⁺ line outputs) of the detection electrodes 26a, 26c taken out of the differential amplifier 45 using the ground electrode as a ground electrode. In FIG. 6, + and-indicate a high potential and a low potential, respectively.

As shown in FIG. 6B, the detection electrodes 26d and 26f on the back side of the detection shaft 24 are connected to one terminal 42b of the power supply 42, and the detection electrode 26e is connected to the other terminal 42a. They may be connected (shown by broken lines). In this way, the detection shaft 24 can be excited not only by the excitation shaft 23 but also by the excitation shaft 23 itself, so that the detection sensitivity when Coriolis force is generated is improved.

The arrangement of the electrode patterns on the tuning fork vibrator 21 is such that both the excitation electrodes 25a and 25b of the excitation shaft 23 are mounted on the base 22 as shown in FIGS. 7 and 8 may be used as long as they are arranged on the same side with respect to the central axis 40 of FIG.

Next, the configuration of the angular velocity sensor on which the tuning fork vibrator 21 is mounted will be described including the order of assembly.

FIG. 9 is a view showing a vibrator unit. In FIG. 9, a vibrator unit 47 in which the clamper block 32 and the tuning fork vibrator 21 are integrated is mounted on a circuit board 48 on which electronic components 48a and 48b are integrally provided. Specifically, the vibrator unit 47 is inserted into the insertion holes formed in the circuit board 48 and soldered by inserting the guide pins 33 a and 33 b formed in the main body 33 into the circuit board 4 via the clamper block 32.
8 is fixed. The circuit board 48 includes the circuit described in FIG.

As shown in FIG. 10, the excitation electrode 25d formed on the back surface of the excitation shaft 23 and the COMMON pattern 25 formed on the circuit board 48 and described in the circuit of FIG.
d 'is connected by a wire 49a.

FIG. 11 is a diagram for explaining the connection between each electrode and the circuit described in FIG.

In FIG. 11, excitation electrodes 25a and 25b formed on the surface of the excitation shaft 23 are connected via wires 30a and 30b via a zero-potential detection electrode 26b formed at the center of the detection shaft 24. The excitation pattern 25a 'formed on the circuit board 48 is connected by a wire 49b. Further, the first detection pattern 26c ′ formed on the detection electrode 26c and the circuit board 48 (S
^- side) are connected by a wire 49c. Also,
The detection electrode 26a and the second detection pattern 26a 'formed on the circuit board 48 are connected by a wire 49d.

On the other hand, the vibrator unit 47 mounted on the circuit board 48 shown in FIG. 11 has the electronic parts 50a and 50b mounted thereon and is fixed to the circuit board 50 adhered to the supporter 51 as shown in FIG. ing. Specifically, the guide pins 33c and 33d of the clamper block 32
Is inserted into an insertion hole (not shown) formed in the circuit board 50 and soldered, whereby the vibrator unit 47 and the circuit board 48 are attached to the circuit board 50 via the supporter 51. The circuit board 48 and the circuit board 5
0 is the position 52a, 52b
The sensor unit 6 is connected by soldering or the like.
5.

Next, as shown in FIG.
a, a sensor unit 65 is mounted on a stem 55 on which an under elastic sheet 61 having elastic projections 63a, 63b is attached, and a square hole 64 formed on the supporter 51.
a and 64b and the elastic protrusions 62a and 62b are guided and inserted in the Y direction, and are assembled in a sandwiched state.

After the assembly, the elastic projections 63a and 63a
b indicates a state in which the sensor unit 65 is sandwiched as shown in FIG.

As shown in FIG. 14, the supporter 51 has an under elasticity on a stem 55 having lead pins 54a to 54c hermetically fixed by sealing glasses 53a to 53c and lead pins 54d hermetically joined by brazing 53d or the like. Each terminal portion 52c, 52d of the flexible substrate 52 is attached via a sheet 61,
52e and 52f are lead pins 54a and 54b, respectively.
It is inserted into 54c and 54d and fixed by soldering. In this state, the angular velocity is measured by applying rotation, and the circuit board 48 is rotated.
Alternatively, the resonance value and the sensitivity are adjusted by trimming the resistance value of a resistor (not shown) mounted on the circuit board 50. After the adjustment of the resonance frequency and the sensitivity, the cap 56 is attached to the stem 55 via the upper elastic sheet 66 as shown in FIG. The cap 56 is vacuum-sucked with the bottom surface attached to the stem 55, and the entire periphery of the bottom surface 56 a of the cap 56 is ring-projection welded or cold-pressed to the stem 55 to thereby obtain the stem 55.
Is to be fixed. Thus, the angular velocity sensor 58 is obtained.

With the above configuration, the sensor unit 65 holding the tuning fork vibrator 21 is sandwiched between the under elastic sheet 61 and the upper elastic sheet 66, and the lead pin 54 implanted on the stem 55 is provided.
Since the a, 54b, 54c, and 54d are fixed only by the soft flexible substrate 52, the angular velocity sensor blocks vibration from the outside of the sensor and is less susceptible to external vibration. I have.

As an implementation other than the implementation of the angular velocity sensor according to the present invention, there is an angular velocity sensor having a tuning fork vibrator 71 as shown in FIGS. 16 and 17, for example. The tuning fork vibrator 71 has a so-called H-shape having two types of excitation axes, a second excitation axis 74 in addition to the first excitation axis 73, and two types of detection axes, a first detection axis 75 and a second detection axis 76. The tuning fork vibrator 71 is configured.

The operation mechanism of the tuning fork vibrator 71 will be described.

FIG. 16 shows the first excitation shaft 73 (the first detection shaft 7).
5) and the second excitation axis 74 (second detection axis 76)
An example in which they are arranged at point symmetric positions with respect to 0 is shown.

The fixed portion 72 is fixed by the clamper block 32.
The tuning fork vibrator 71 to which a and 72b are fixed is excited by the first excitation shaft 73 and the second excitation shaft 74 and the tuning fork effect, as shown in FIG.
74 and the first and second detection shafts 75 and 76 are excited in in-plane directions (directions of arrows 96a to 96d and arrows 97a to 97d).

Specifically, the first excitation shaft 73 is indicated by an arrow 96b.
Vibrates in the direction of the first detection axis 75 due to the tuning fork effect.
Vibrates in the direction of arrow 96a, and similarly, the second excitation shaft 74 vibrates in the direction of arrow 97a.
The detection shaft 76 vibrates in the direction of the arrow 97b, and at the next moment, the first excitation shaft 73 and the first detection shaft 75 are moved by the arrows 96a and 96a.
Vibration in the direction opposite to the direction b (directions of arrows 96c and 96d), and the second excitation shaft 74 and the second detection shaft 76
Vibration occurs in the direction opposite to the directions of 7b and 97a (directions of arrows 97d and 97c), and this operation, that is, the first excitation shaft 73 and the first detection shaft 75, and the second excitation shaft 74 and the second detection shaft 76 come close to each other. The vibration in the in-plane direction that separates is repeated. That is, the first tuning fork vibrator composed of the combination of the first excitation shaft 73 and the first detection shaft 75 and the second tuning fork vibrator composed of the combination of the second excitation shaft 74 and the second detection shaft 76 open and close in reverse. Will repeat.

In such an in-plane excitation state, when a rotational angular velocity Ω about the center axis 98 of the tuning fork vibrator 71 is applied to the tuning fork vibrator 71, the Coriolis force is applied in a direction substantially orthogonal to the excitation direction. Occurs, the first and second excitation shafts 7
The third and the 74 and the first and the second detection axes 75 and 76 are shown in FIG.
And as shown in FIG.
The vibration of the component of d occurs. Then, the magnitude of the applied angular velocity is measured by detecting the vibration component with detection electrodes (not shown) formed on the first and second detection shafts 75 and 76.

FIG. 17 shows the tuning fork vibrator 71 shown in FIG.
Shows an example in which the first excitation axis 73 (first detection axis 75) and the second excitation axis 74 (second detection axis 76) are arranged symmetrically with respect to the center line 69. 1
The tuning fork vibrator (composed of the first excitation shaft 73 and the first detection shaft 75) and the second tuning fork vibrator (composed of the second excitation shaft 74 and the second detection shaft 76) repeat the same opening and closing operation. .

When a rotation angular velocity Ω about the center axis 98 of the tuning fork vibrator 71 as a rotation center is applied,
(B) and the first and second excitation shafts 7 as shown in FIG.
3, 74 are bent in the same direction 100a, 100b,
The first and second detection axes 75, 76 are also in the same direction 100c, 10c.
It will bend to 0d.

The vibration components are converted into the first and second detection shafts 75 and 7.
The magnitude of the applied angular velocity is measured by detecting with a detection electrode (not shown) formed in 6.

Now, a method for manufacturing the tuning fork vibrator 21 will be described.

First, as shown in FIG. 18A, a piezoelectric ceramic sheet material 101 fired in a sheet shape and finished to a predetermined thickness is prepared. Next, FIG.
After electrodes are formed on the entire surface of the piezoelectric ceramic sheet material 101 by electroless Ni plating or gold sputtering as shown in FIG. 18, end faces 101a to 101d of the piezoelectric ceramic sheet material 101 are processed as shown in FIG. The electrodes are removed from the end surfaces 101a to 101d, and the end surfaces 101a and 101b serving as the reference surfaces for processing are finished.
As the plating applied to the piezoelectric ceramic sheet material 101, in order to achieve photolithographic properties and wire bonding properties, low-phosphorus electroless Ni plating or Ni-B (boron) electroless Ni plating is used as a base, and glossiness is further provided thereon. Electric Ni plating is applied.

Next, as shown in FIG. 18D, the front and back electrodes of the piezoelectric ceramic sheet material 101 are subjected to photolithography to collectively form detection electrodes including excitation electrodes and zero potential electrodes.

Next, as shown in FIG. 19 (a), polarization 27a, 27b, 28 in each direction shown in FIG.
a, 28b, and 29a to 29d.

Here, the polarization method will be specifically described with reference to FIGS. 20 and 21.

FIG. 20A shows a piezoelectric ceramic sheet material 101 on which excitation electrodes and detection electrodes including zero potential electrodes are collectively formed by photolithography.
(+) Electrode 105, (-) electrode 106 and zero potential electrode 1
07 is formed. The two-dot chain line 108 shows the shape of the tuning fork vibrator cut out after polarization.
The tuning fork vibrator 21 shown in FIG. FIG. 20 (b) shows a cross section of the excitation axis 23 and the detection axis 24, and each arrow indicates a polarization direction after polarization. The excitation electrodes 25b and 25c and the detection electrode 26c which are adjacent to the excitation axis 23 and the detection axis 24 are shown. , And 26d are laid out in the same direction as the polarization direction after polarization (the direction of arrow 27b and arrow 28b).

The polarization procedure is as shown in FIG.
First, the corresponding electrodes (excitation electrode 25c, detection electrode 26
With d) connected to GND, a negative polarization voltage is applied to the (-) electrode (excitation electrode 25b, detection electrode 26c) on the surface (TOP surface) to perform first plane perpendicular polarization. Arrow 27
b and 28b indicate polarization directions.

Next, as shown in FIG. 21 (b), the corresponding electrodes (the excitation electrode 25d and the detection electrode 26f) on the back surface are connected to GND.
With the (+) electrode (excitation electrode 25
a, A second polarization perpendicular to the surface is performed by applying a positive polarization voltage to the detection electrode 26a). Arrows 27a and 28a indicate the polarization directions.

Finally, as shown in FIG. 21 (c), with the zero-potential electrodes (detection electrodes 26b and 26e) connected to GND, the front and rear electrodes of the same polarity (excitation electrode 25a and detection electrode 26a) are connected.
a, the excitation electrode 25c and the detection electrode 26d are connected to each other, and the excitation electrode 25b, the detection electrode 26c, the excitation electrode 25d and the detection electrode 26f are connected to each other, and positive and negative polarization voltages are applied to the zero potential electrode (the detection electrode 26b). , 26e) are polarized simultaneously (in the directions of arrows 29a and 29b and arrows 29c and 29d). FIG. 21D shows the polarization state of a plurality of transducers that have been polarized through the above polarization process.

After polarization as described above, FIG.
As shown in (b), the piezoelectric ceramic sheet material 101 is divided into strip sheets 103a and 103b. And FIG.
As shown in FIG. 9 (c), each strip sheet 103a, 103b
Strip sheet 10 having the shape of tuning fork vibrator 21
4 is cut from this strip sheet 104 as shown in FIG.
The tuning fork vibrator 21 is divided into individual pieces as shown in FIG.

Next, an adjustment method for reducing kinking vibration during the assembly process will be described.

FIG. 22 is a diagram schematically showing the mechanism of generating the A output value and the B output value when oblique vibration occurs due to kinking. Note that the A output value is the amount of charge generated on the detection electrode 26a, and the B output value is
This is the amount of charge generated in c.

FIG. 22A shows the state at the time of no excitation.
A output value and B output value are not output.

FIG. 22B shows an ideal in-plane vibration in which the vibration direction is the direction of the arrow 115. Since no oblique vibration occurs, the A output value and the B output value have the same charge. Amount (−10).

FIG. 22C shows a case of a so-called downward slanting vibration in the direction of arrow 116. When the tuning fork vibrator 21 is in this state, the amount of kinking applied to the detecting electrode 26c is smaller than the amount of kinking applied to the detecting electrode 26a, so that the amount of charge generated by the y-direction compressive force applied to the detecting electrode 26c is applied to the detecting electrode 26a. It becomes smaller than the amount of electric charge generated by the applied compressive force in the y direction. That is, the detection electrode 26a
, The amount of charge (−10) generated by the compressive force in the x direction is y
Since the amount of charge (−3 (portion enclosed in a square in the figure)) generated by the compressive force in the direction is added, the amount of generated charge is (−13), whereas the detection electrode 26c has the x-direction. Since the charge amount (−10 (portion surrounded by a square in the figure)) generated by the compressive force in the y direction is added to the charge amount (−10) generated by the tensile force, the generated charge amount is (−12). . Therefore, the B output value (-12) is smaller than the A output value (-13).

FIG. 22D shows a case of a so-called oblique vibration rising in the right direction in the direction of arrow 117. When the tuning fork vibrator is in this state, the amount of twist applied to the detection electrode 26c is smaller than the amount of twist applied to the detection electrode 26a.
The amount of charge generated by the tensile force in the y direction applied to the detection electrode 26c is smaller than the amount of charge generated by the tensile force in the y direction applied to the detection electrode 26a. That is, since the charge amount (−10) generated by the compressive force in the x direction and the charge amount (+3 (the portion surrounded by a square in the figure)) generated by the tensile force in the y direction are added to the detection electrode 26a, The generated charge amount is (−7), whereas the detection electrode 26c has a charge amount (−10) generated by a tensile force in the x direction and a charge amount (−2 (FIG. )) Is added,
The generated charge amount is (−12). Therefore, the B output value (-12) is larger than the A output value (-7).

As described above, by monitoring the output difference between the A output value and the B output value, it is possible to determine the magnitude of the twist and the direction of the twist. Then, as shown in FIG.
When the device 1 is excited while mounted on the clamper block 32, as shown in FIG. 22 (c), if a diagonal vibration downward in the right direction in the direction of arrow 116 occurs, the direction in which the kinks are directed (the direction of arrow 118, And, by chamfering one or both of the corner 119 of the excitation shaft 23 and the corner 119 'of the detection shaft 24 located in the direction of arrow 118'), as indicated by oblique lines 120 or 120 ', the kinks are formed. Vibration can be reduced.

Similarly, as shown in FIG.
In the case where an oblique vibration rising upward to the right in the direction of arrow 7 occurs, the direction in which the kinks are going (the direction of arrow 121 and the direction of arrow 12)
Either one or both of the corner 122 of the excitation shaft 23 and the corner 122 ′ of the detection shaft 24 located in the direction 1 ′)
By chamfering like the oblique line 123 or the oblique line 123 ', kinking vibration can be reduced.

Next, a method of adjusting characteristics such as sensitivity as an angular velocity sensor in the assembling process will be described.

In FIG. 23, the sensor unit 65 includes elastic projections 62a, 62 formed on the under elastic sheet 61.
2b, 63a, and 63b, and stands independently while being elastically held on the stem 55. In this state, the lead pins 54a, 5a
4b, 54c, and 54d are inserted and mounted, and rotation (angular velocity) is applied to measure Coriolis output. Based on the measurement data, characteristics such as sensitivity as a sensor are adjusted by trimming a resistor mounted or formed on the circuit board 48 or the circuit board 50. After the end of the characteristic adjustment, it is sealed with a cap 56 as shown in FIG.
The Coriolis output measurement in a state where the tuning fork vibrator 21 is elastically held on the stem 55, which is in a state close to the state after the can sealing, has little difference from the measurement data of the angular velocity sensor 58 of the final shape, and high-precision adjustment is possible. It becomes possible.

As described above, in the present embodiment,
Base 22 on which protruding fixing portions 22a and 22b are formed
And an excitation shaft 23 erected from the base 22 and opposed to the base 22
Tuning fork vibrator 21 made of piezoelectric ceramics having a detection shaft 24 and a ridge 22 of fixed portions 22a and 22b
Arm members 34, 35 having V grooves 34a, 35a fitted to c to 22f are formed, and the tuning fork vibrator 21 is held by fitting the fixing portions 22a, 22b to the V grooves 34a, 35a. A clamper block 32 is provided, excitation electrodes 25a to 25d are provided on the front and back surfaces of the excitation shaft 23, and detection electrodes 26a to 26f are provided on the front and back surfaces of the detection shaft 24. Further, as the polarization direction of the excitation shaft 23,
Excitation electrodes 25a and 25d and excitation electrodes 25b
The surface perpendicular polarization is performed so that the polarization directions are opposite to each other.
4, detection electrodes 26a, 26c, 26d on both sides of the front and back surfaces,
In 26f, the surface perpendicular polarization is performed in the opposite direction on the front and back surfaces, and the center detection electrodes 26b and 26
e, detection electrodes 26a, 26c, 26d, 26f on both sides
In this case, the tuning fork vibrator 21 is excited in the in-plane direction, and the center axis of the tuning fork vibrator 21 is excited in the in-plane direction. The angular velocity can be detected by detecting the Coriolis force generated in the direction perpendicular to the plane perpendicular to the excitation direction by the application of the angular velocity around 40 as the deflection of the detection shaft 24 in the direction perpendicular to the surface.

Further, since the tuning fork vibrator 21 can be integrally formed with a unimorph, no adhesive is required as in the case of forming a bimorph tuning fork vibrator, and the vibration characteristics can be stabilized. In addition, the characteristics of the tuning fork vibrator 21 can be utilized to stabilize the in-plane vibration characteristics.

Further, the clamper block 32 holding the tuning fork vibrator 21 deforms the arm members 34 and 35 when holding the tuning fork vibrator 21, so that a spring property can be obtained. The tuning fork vibrator 21 can be stably held, and the influence of the variation in fixing on the detection sensitivity can be reduced.

Furthermore, the shape of the clamper block 32 is
By using the equal beam structure in which the stress is equalized, the size of the clamper block 32 can be reduced and the clamping force can be increased.

Further, since the excitation of the tuning fork vibrator 21 is an in-plane tuning fork excitation, the excitation efficiency can be improved, and the excitation shaft 23 is formed with two electrodes on the front and back surfaces to form the in-plane excitation. The area of the excitation electrode can be made large, so that the excitation efficiency can be improved.

Also, the detection electrodes 26b and 26c having zero potential due to in-plane polarization are arranged at the center of the detection axis 24, and the detection electrodes 2 having potentials of + and-opposite directions on both sides due to plane perpendicular polarization.
By arranging 6a, 26c, 26d, and 26f, the detection output of the Coriolis force can be taken out differentially between the electrodes on both sides and the electrode at the center zero potential, so that noise can be canceled and the detection sensitivity can be obtained. Can be improved.

Furthermore, since the excitation electrodes 25a to 25d and the detection electrodes 26a to 26f are led out to the base 22, the signal line connection with the circuit board 48 can be performed on the base 22 with less vibration. Reliability can be improved.

Further, since the two excitation electrodes of the excitation shaft 23 led to the base 22 are arranged only on one side of the central axis 40 of the tuning fork vibrator 21, the base 22 itself does not vibrate during excitation. Therefore, the Coriolis detection sensitivity can be improved.

Further, since the tuning fork vibrator 21 is mounted on the circuit board 48 via the clamper block 32, the clamper block 32 can be easily mounted directly on the circuit board 48 by soldering or the like. The mounting reliability of the mounting 21 can be increased, and the workability of mounting can be improved.

Also, by using tungsten, phosphor bronze, or stainless steel having a large specific gravity and a high spring property as the clamper block 32, the vibration leakage of the tuning fork vibrator 21 and the vibration of the Coriolis force detection shaft are reduced. Thus, the tuning fork vibrator 21 can be stably held by the clamper block 32.

Further, if the excitation of the detection shaft 24 is performed not only by the subordinate tuning fork drive from the excitation shaft 23 but also by the drive of the detection shaft 24 itself, the detection shaft 24 is assist-driven, so that the amplitude is increased. Can be increased, and the detection sensitivity is improved.

The center axis (rotation axis) of the tuning fork vibrator 21
Since the tuning fork vibrator 21 is mounted on the circuit board 48 so that the direction of the yaw rotation axis is the same as the direction of the yaw rotation axis 40, the angular velocity can be detected with high accuracy when the yaw rotation of the automobile or the like is performed.

Further, since the sensor unit 65 has a floating structure in which the sensor unit 65 is sandwiched between the stem 55 and the cap 56 via the under elastic sheet 61 and the upper elastic sheet 66, the influence of external vibration noise can be minimized. , And can be made strong against a drop impact.

In manufacturing the tuning fork vibrator 21, a piezoelectric ceramic sheet material 60 is prepared, and the excitation electrodes 25a to 25d and the detection electrodes 26a to 26d are collectively formed on the piezoelectric ceramic sheet material 60 by photolithography.
26f is formed, and then a voltage is applied to the excitation electrodes 25a to 25d and the detection electrodes 26a to 26f to collectively perform polarization processing in the polarization direction as shown in FIG. Since the vibrator 21 is cut out, the tuning fork vibrator 21, which is the heart of the angular velocity sensor 58, can be manufactured by collective electrode formation, collective polarization processing, and collective cutout method, and the cost of the angular velocity sensor 58 can be reduced. it can.

Since the electrodes adjacent to the excitation axis 23 and the detection axis 24 have the same polarization direction, the electrodes do not interfere with each other and are depolarized. To be stable,
The polarization variation of each transducer can be eliminated.

Further, since the electrodes of the tuning fork vibrator 21 are formed of a combination of low phosphorus type electroless Ni plating (or Ni-B (boron) type electroless Ni plating) and bright electric Ni plating, the Patterning by lithography and aluminum wire bonding can be stably performed, and the quality of the electrode pattern can be improved.

Further, the clamper block 32 on which the low melting point plating 37 has been processed is prepared, and the fixing portions 22a and 22b of the tuning fork vibrator 21 cut out from the piezoelectric ceramic sheet material 60 are fixed to the V-groove 3 of the clamper block 32.
4a and 35a, the clamper block 32 is heated by the heater block 38 to fill the gap between the fixing portions 22a and 22b and the V-grooves 34a and 35a with the low melting point plating 37. Can be brought into close contact with the fixing portions 22a and 22b, and the tuning fork vibrator 21 can be stably and reliably attached to the clamper block 32.

A holding member (clamper block) 32
In a state where the tuning fork vibrator 21 is clamped to
By monitoring the output from the detection electrodes 26a and 26c, unnecessary kinking vibration can be detected before the assembly, and the kinking vibration can be reduced by chamfering the excitation shaft 23 or the detection shaft 24. Sensitivity can be improved.

Further, since the characteristics such as the sensitivity as the angular velocity sensor can be adjusted in the same state (floating state) as before the can sealing before the can sealing, the adjustment accuracy is high and the yield is good. The manufacture of the sensor becomes possible.

[0120]

As described above, according to the present invention,
It is possible to provide a tuning fork vibrator, an angular velocity sensor, and a method of manufacturing an angular velocity sensor that have higher angular velocity detection accuracy than conventional ones.

[Brief description of the drawings]

1A is a front view of a tuning fork vibrator of an angular velocity sensor according to an embodiment of the present invention. FIG. 1B is a bottom view of an excitation axis and a detection axis showing a polarization direction of the tuning fork vibrator shown in FIG.

2A is a side view of the tuning fork vibrator shown in FIG. 1. FIG. 2B is a rear view of the tuning fork vibrator shown in FIG.

3A is a front view showing a state in which the tuning fork vibrator shown in FIG. 1 is held by a clamper block. FIG. 3B is a side view of the tuning fork vibrator and the clamper block shown in FIG. Top view of the tuning fork vibrator and the clamper block shown in a)

4A is a partial detailed view of the tuning fork vibrator and the clamper block shown in FIG. 3A. FIG. 4B is a top view showing a state where the tuning fork vibrator and the clamper block shown in FIG. 3A are heated by a heater.

5A is a front view showing an excitation state of the tuning fork vibrator shown in FIG. 1; FIG. 5B is a side view showing a vibration state of the tuning fork vibrator shown in FIG. 1 when Coriolis force is generated; FIG. Perspective view of the tuning fork vibrator in the state of FIG.

6A is a circuit diagram showing an angular velocity detecting circuit of the tuning fork vibrator shown in FIG. 1; FIG. 6B is a circuit diagram showing an angular velocity detecting circuit different from that of FIG. 6A of the tuning fork vibrator shown in FIG.

FIG. 7 is a diagram showing an angular velocity sensor according to an embodiment of the present invention;
Electrode pattern diagram showing a different pattern from

FIG. 8 shows an angular velocity sensor according to one embodiment of the present invention.
Pattern diagram showing a pattern different from FIG. 8 and FIG.

9A is a front view showing a state in which a tuning fork vibrator unit of an angular velocity sensor according to an embodiment of the present invention is mounted on a substrate. FIG. 9B is a front view showing the tuning fork vibrator unit shown in FIG. FIG. 9C is a top view of the tuning fork vibrator unit and the substrate shown in FIG.

10A is a front view showing a state in which the back surface of the tuning fork vibrator unit of the angular velocity sensor according to one embodiment of the present invention is wire-bonded to a substrate. FIG. 10B is a front view showing the tuning fork vibrator unit shown in FIG. Substrate bottom view

11A is a front view showing a state in which the surface of the tuning fork vibrator unit of the angular velocity sensor according to one embodiment of the present invention is wire-bonded to a substrate. FIG. 11B is a front view showing the tuning fork vibrator unit shown in FIG. Side view of substrate (c) Top view of tuning fork vibrator unit and substrate shown in FIG.

12A is a top view showing a state where the tuning fork vibrator unit of the angular velocity sensor according to one embodiment of the present invention is attached to a substrate and a supporter. FIG. 12B is a top view showing the tuning fork vibrator unit and the substrate shown in FIG. (C) Side view of the tuning fork vibrator unit, substrate and supporter shown in FIG.

13A is a front view showing the assembling of the sensor unit and the stem of the angular velocity sensor according to one embodiment of the present invention. FIG. 13B is a side view of the sensor unit and the stem shown in FIG. Top view of the sensor unit and the stem shown in FIG.

14A is a front view showing a state in which a sensor unit of an angular velocity sensor according to an embodiment of the present invention is attached to a stem. FIG. 14B is a side view of the sensor unit and the stem shown in FIG. Top view of the sensor unit and the stem shown in FIG.

15A is a front view of an angular velocity sensor according to an embodiment of the present invention. FIG. 15B is a side view of the angular velocity sensor shown in FIG. 15A. FIG. 15C is a top view of the angular velocity sensor shown in FIG.

16 (a) is a front view showing an excitation state of a tuning fork vibrator having a configuration different from that of the tuning fork vibrator shown in FIG. 1; (b) a vibration state of the tuning fork vibrator shown in FIG. 16 (a) when Coriolis force is generated (C) A perspective view of the tuning fork vibrator in the state of FIG. 16 (b)

17A is a front view showing an excitation state of a tuning fork vibrator having a configuration different from that of the tuning fork vibrator shown in FIGS. 1 and 16; FIG. 17B is a diagram showing a state in which a Coriolis force is generated by the tuning fork vibrator shown in FIG. (C) Perspective view of the tuning fork vibrator in the state of FIG. 17 (b)

18 (a) to (d) are perspective views showing a procedure for manufacturing the tuning fork vibrator shown in FIG.

19 (a) to 19 (d) are perspective views showing a procedure for manufacturing a tuning fork vibrator continued from FIG. 18 (d).

20A is a pattern diagram formed on a voltage sheet. FIG. 20B is a cross-sectional view showing a polarization state of an excitation axis and a detection axis of the tuning fork vibrator.

21A is a cross-sectional view illustrating a first plane perpendicular polarization of the tuning fork vibrator illustrated in FIG. 1; FIG. 21B is a cross-sectional view illustrating a second plane perpendicular polarization of the tuning fork vibrator illustrated in FIG. Sectional view showing in-plane polarization of the tuning fork resonator shown in FIG. 1 (d) Sectional view showing the polarization state of a plurality of tuning fork resonators similar to the tuning fork resonator shown in FIG.

22 (a) is a cross-sectional view showing the state of charge generation when the tuning fork vibrator shown in FIG. 1 is not excited, and (b) is a cross-sectional view showing the state of charge generation when the tuning fork vibrator shown in FIG. 1 is excited in a plane. c) Cross-sectional view showing the state of charge generation during kinking vibration of the tuning fork vibrator shown in FIG. 1. (d) The state of charge generation of the tuning fork vibrator shown in FIG. 1 during kinking vibration in the direction opposite to that of FIG. Cross section shown

23A is a front view showing a measurement state before characteristic trimming of the angular velocity sensor according to one embodiment of the present invention. FIG. 23B is a side view of the angular velocity sensor shown in FIG. Top view of the angular velocity sensor shown in ()

24A is a perspective view of a conventional angular velocity sensor. FIG. 24B is a perspective view of the angular velocity sensor shown in FIG.

FIG. 25 is a characteristic diagram showing a resonance point of the non-resonant angular velocity sensor.

[Explanation of symbols]

22a, 22b Fixed part 22 Base 23 Excitation axis (first excitation axis) 24 Detection axis (first detection axis) 21 Tuning fork vibrator 25a, 25b, 25c, 25d Excitation electrode 26a, 26b, 26c, 26d, 26e, 26f
Detection electrode 22c, 22d, 22e, 22f Ridge part 34, 35 Arm member (fitting part) 32 Clamper block (holding member) 58 Angular velocity sensor 40 Central axis 33a, 33b, 33c, 33d Guide pin 48 Circuit board 50 Circuit board 34a , 35a V-groove 47 Vibrator unit 61 Under elastic sheet 66 Upper elastic sheet 55 Stem 56 Cap 52 Flexible board (flexible board) 71 Tuning fork vibrator 73 Excitation axis (first excitation axis) 74 Excitation axis (second excitation axis) 75 Detection axis (first detection axis) 76 Detection axis (second detection axis) 60 Piezoelectric ceramic sheet material (sheet material) 37 Low melting point plating (plating applied to holding member) 119, 119 'Cad portions 122, 122' Cad part 51 Supporter 65 Sensor unit 54a, 54b, 54c, 54d Lead pin

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Haruhiko Sekino 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama, Kanagawa Prefecture Inside Matsushita Communication Industrial Co., Ltd. No.3-1, Matsushita Communication Industrial Co., Ltd. F-term (reference) 2F105 AA01 BB02 BB11 CC01 CD13

Claims (20)

[The claims] 1. A piezoelectric device comprising: a base on which a projection-shaped fixing portion is formed; a first excitation axis and a first detection axis which are erected from the base and arranged to face each other; With
The first excitation axis and the first detection axis are excited in an in-plane direction in which the first excitation axis and the first detection axis are close to and separated from each other.
In a tuning fork vibrator that detects a Coriolis force generated when an angular velocity that is parallel to a detection axis and is applied to these two axes with a center axis opposed to the rotation axis as a rotation in a direction perpendicular to the surface, the first excitation axis is Two sets of excitation electrodes led to the base and opposed to each other are provided on the front and back surfaces, and the two sets of excitation electrodes are vertically polarized so that the polarization directions are opposite to each other. On the back surface, three sets of detection electrodes led out to the base and opposed to each other are provided, and the detection electrodes at both ends of the three sets of detection electrodes are polarized perpendicular to the surface so as to be in opposite polarization directions to each other. A center detection electrode of the set of detection electrodes is in-plane polarized so as to have a zero potential between the detection electrodes at both ends, and one of the two sets of excitation electrodes on the first detection axis side is excited. An electrode and the third one of the three detection electrodes. Tuning fork vibrator, wherein the direction of polarization of the pair of detection electrodes of the excitation axis side are identical. 2. The tuning fork vibrator according to claim 1, further comprising: an arm-shaped fitting portion for sandwiching a ridge of the projection-shaped fixing portion of the tuning fork vibrator, wherein the fitting portion has the ridge. And a holding member that holds the tuning fork vibrator by fitting a portion of the angular velocity sensor. 3. In the electrode pattern arrangement of the tuning fork vibrator on the base, two excitation electrodes of the first excitation shaft led to the base are provided only on one side of a center axis of the tuning fork vibrator. The angular velocity sensor according to claim 2, wherein the angular velocity sensor is arranged. 4. The tuning fork vibrator is mounted on the circuit board by fixing the pin to the circuit board, wherein the holding member has a pin.
2. The angular velocity sensor according to 1. 5. The clamp according to claim 2, wherein the holding member is a spring-shaped V-groove clamper having a V-groove in the fitting portion and having equalized stress. Angular velocity sensor. 6. The angular velocity sensor according to claim 2, wherein the holding member is made of tungsten, phosphor bronze, or stainless steel. 7. A Coriolis force detection circuit for generating an angular velocity, wherein the excitation of the first detection axis is performed not only by driving the tuning fork from the first excitation axis but also by driving the first detection axis itself. The angular velocity sensor according to any one of claims 2 to 6, wherein 8. The tuning fork vibrator is mounted on the circuit board such that the direction of the rotation axis of the tuning fork vibrator and the direction of the yaw rotation axis are the same. An angular velocity sensor according to any one of the above. 9. A vibrator unit formed by holding the tuning fork vibrator on the holding member and mounting the tuning fork vibrator on the circuit board is sandwiched between a stem and a cap via an under elastic sheet and an upper elastic sheet. 9. The tuning fork vibrator is elastically supported by connecting a signal line with a flexible board.
The angular velocity sensor according to any one of the above. 10. A second excitation shaft, wherein the tuning fork vibrator is arranged to face the first detection axis with the base interposed therebetween, and has a polarization direction and an electrode having the same conditions as the first excitation axis. A second detection axis having a polarization direction and an electrode under the same conditions as the first detection axis, the second excitation axis being disposed opposite to the first excitation axis with a base interposed therebetween, the first excitation axis and the second excitation When the shaft is excited in the in-plane direction, the second excitation axis and the second detection axis are excited in the opposite directions to the excitation directions of the first excitation axis and the first detection axis, and are excited. , The first Coriolis force generated when an angular velocity is applied around the rotation axis.
The angular velocity sensor according to any one of claims 2 to 9, wherein the detection axis and the second detection axis vibrate in directions opposite to each other in a direction perpendicular to the plane. 11. A second excitation shaft, wherein the tuning fork vibrator is arranged to face the first excitation shaft with the base interposed therebetween, and has a polarization direction and an electrode under the same conditions as the first excitation shaft. A second detection axis having a polarization direction and an electrode under the same conditions as the first detection axis, the second excitation axis being disposed opposite to the first detection axis with a base interposed therebetween, the first excitation axis and the second excitation When the shaft is excited in the in-plane direction, the second excitation axis and the second detection axis are excited in the same direction with respect to the excitation direction of the first excitation axis and the first detection axis. , The first Coriolis force generated when an angular velocity is applied around the rotation axis.
The angular velocity sensor according to any one of claims 2 to 9, wherein the detection axis and the second detection axis vibrate in the same direction in a direction perpendicular to the plane. 12. The method of manufacturing an angular velocity sensor according to claim 2, wherein, when manufacturing the tuning fork vibrator, a sheet material made of a piezoelectric element is prepared and photolithography is performed on the sheet material. Collectively forming the excitation electrode and the detection electrode, and then applying a voltage to the excitation electrode and the detection electrode to collectively perform a polarization process in the polarization direction. A method for manufacturing an angular velocity sensor, comprising cutting out a vibrator. 13. When a voltage is applied to the excitation electrode and the detection electrode to perform polarization processing collectively in the polarization direction,
The polarization direction of one set of the excitation electrodes on the first detection axis side of the two sets of excitation electrodes is the same as the polarization direction of one set of the detection electrodes on the first excitation axis side among the three sets of detection electrodes. The method for manufacturing an angular velocity sensor according to claim 12, wherein the polarization processing is performed as described above. 14. When a voltage is applied to the excitation electrode and the detection electrode to perform polarization processing collectively in the polarization direction,
With the opposite corresponding electrode on the back surface of the sheet material connected to GND, a negative polarization voltage is applied to the negative electrode on the front surface of the sheet material to perform surface perpendicular polarization, and then the opposite surface of the sheet material is opposed. After applying a positive polarization voltage to the positive electrode on the surface of the sheet material with the corresponding electrode connected to GND to perform surface perpendicular polarization, the center detection electrode of the three sets of detection electrodes is connected to GND. In this state, the same positive and negative electrodes on the front and back surfaces of the sheet material are connected to each other, and positive and negative polarization voltages are applied to simultaneously in-plane polarize both sides of the central detection electrode among the three detection electrodes. 14. The method for manufacturing an angular velocity sensor according to claim 12, wherein: 15. A low phosphorus type electroless Ni plating or N
An iB (boron) type electroless Ni plating is performed, and a combine plating is performed by applying a bright electric Ni plating on the base plating.
The method for manufacturing an angular velocity sensor according to any one of the above. 16. Preparing the plated holding member, fitting the fixed portion of the tuning fork vibrator cut out of the sheet material to the fitting portion of the holding member, and then holding the plate. The angular velocity sensor according to any one of claims 12 to 15, wherein the member is heated to melt the plating applied to the holding member and fill the gap between the fixed portion and the fitting portion. Production method. 17. The method for manufacturing an angular velocity sensor according to claim 2, wherein each of said excitation electrodes formed on said excitation shaft of said tuning fork vibrator clamped to said holding member. By applying an AC voltage,
The tuning fork vibrator is excited in the in-plane direction, and then
By monitoring the difference between the respective output voltages generated between the detection electrodes at both ends formed on the same surface side of the detection axis and the detection electrode at the center, the presence or absence of kinking vibration of the tuning fork vibrator is determined. And determining the magnitude and direction of the kinking when kinking occurs in the tuning fork vibrator. 18. When the tuning fork vibrator has a kinking vibration as a result of the determination of the presence or absence of kinking vibration of the tuning fork vibrator, a chamfered portion of either the excitation shaft or the detection shaft is chamfered. 18. The method for manufacturing an angular velocity sensor according to claim 17, wherein kinking vibration of the tuning fork vibrator is reduced. 19. When chamfering one of the excitation shaft and the detection shaft, chamfering one or more of the excitation shaft and the detection shaft of the detection shaft located in the direction in which the kinking is directed. 19. The method according to claim 18, wherein kinking vibration of the tuning fork vibrator is reduced. 20. The method for manufacturing an angular velocity sensor according to claim 9, wherein the tuning fork vibrator is mounted on the circuit board connected by the flexible board via the holding member. , The sensor unit combined with the supporter is held on the stem by being sandwiched by the elastic projections of the under elastic sheet, and the angular velocity is set in a state where the signal line of the flexible board is connected to the lead pin formed on the stem. And measuring the Coriolis output by applying voltage, and adjusting the characteristics by trimming a resistor mounted or formed on the circuit board based on the measured data detected. Method.