JPH03156313A - Oscillating gyroscope - Google Patents

Abstract

PURPOSE:To make temperature drift small, to make sensitivity high and to decrease man-hours by providing driving electrodes for exciting bending oscillations on an oscillating body, and providing detecting electrodes for detecting piezoelectricity corresponding to strain generated in the oscillating body in response to the angular velocity around the longitudinal axis of the oscillating body. CONSTITUTION:These electrodes comprise driving electrodes 3a, 3b, 4a and 4b and detecting electrodes 5a and 5b. The electrodes 3a and 3b are formed on a face A and a face C, respectively, and interconnected on a sound piece 10 with thin films. The electrodes 4a and 4b are formed on a surface B and a surface D, respectively, and interconnected on the sound piece 10 with thin films. Meanwhile, the electrodes 5a and 5b are formed on a surface B and a surface D, respectively. Since supporting wires 1a, 1b, 2a and 2b are connected to the driving electrodes and the detecting electrodes having the different polarities, the supporting wires can be used for the role of lead wires for applying driving voltages and leading out the detected voltages. Therefore, when the patterns of the electrodes 3a and 3b are made to correspond to the patterns of the electrodes 4a and 4b, the effects of the electric fields of the electrodes 3a and 3b on the electrodes 5a and 5b can be alleviated.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a vibrating gyro that is attached to a moving body such as an aircraft, a car, or a robot and detects the angular velocity of the moving body, and in particular, it relates to a vibrating gyro that detects the angular velocity of the moving body such as an aircraft, a car, or a robot. The present invention relates to a vibrating gyroscope that measures the angular velocity around the axis of a prismatic vibrating body based on the Coriolis force that the vibrating body receives when the vibrating body is excited with bending vibration.

(Prior Art) In addition to the vibrating piece shape targeted by the present invention, vibrating gyros include wire shapes, tuning fork shapes, cylindrical shapes, cup shapes, and the like. All of these types of vibrating gyroscopes have a simple structure that does not include a rotating part such as a rotor, and are inexpensive.

FIG. 7 is a perspective view conceptually showing a conventional sound piece-shaped vibrating gyroscope. This vibrating gyroscope consists of a vibrating bar 20 that is a square metal prism, a drive piezoelectric element 6 that is attached to one side of the vibrating bar 20 with adhesive, and a driving piezoelectric element 6 that is glued to the other side of the vibrating bar 20. The detection piezoelectric element 7 is pasted with adhesive, and the support wire la is fixed at one end to the support portion of the vibrating bar 20.

lb, 2a, and 2b. In addition, in the figure,
x, y, and z indicate respective coordinate axes of orthogonal coordinates.

The vibrating bar 20 is made of an alloy of nila gel, chromium, and titanium, or erinba, and has support wires la and lb.

It is supported at a fixed position with respect to the housing by the tension of 2a and 2b. Although the casing is not shown in FIG. 7, the structure of supporting the sound bar at a fixed position relative to the casing using support wires is disclosed in, for example, Utility Model No. 6 by the same applicant as the present application.
Detailed information can be found in No. 1-47049 "Vibration Gyro".

A driving lead wire 8 is attached to the driving piezoelectric element 6. By applying an alternating current voltage of a predetermined frequency to the driving piezoelectric element 7'6 through the driving lead wire 8, the vibrating bar 20
undergoes bending vibration in the X-7 plane. The frequency of the bending vibration is a unique value determined from the dimensions and material of the vibrating bar 20, and the frequency of the applied AC voltage is made to match the bending vibration frequency. The antinode of the bending vibration is located at the center of the vibrating bar 20 in the longitudinal direction. Further, the bending vibration nodes are located at positions of 0.2242 from the left end and the right end, respectively, when the total length of the vibrating bar is 1.

Support parts 11 and 12 are the nodes of bending vibration,
Support wires Ia, lb and 2a, 2b are attached to these support parts 11 and 12, respectively.

When an alternating current voltage is applied to the vibrating gyroscope having such a structure and the vibrating bar 20 is excited with bending vibration in the x-z plane, when the housing moves around the Z-axis at an angular velocity Ω, the vibrating bar 2
0 receives the Coriolis force, and the vibrating bar 20 is distorted and vibrates in the yz plane. At this time, the detection piezoelectric element 7
Piezoelectricity is generated according to the distortion in the plane, and the piezoelectricity is taken out via the detection lead wire 9. In this way, the angular velocity Ω is detected as the piezoelectric magnitude of the output of the detection piezoelectric element 7.

(The problem to be solved by the invention 11! [) As mentioned above, the 7th problem
In the conventional vibrating gyroscope shown in the figure, a piezoelectric element 6 for excitation of a vibrating bar 20 and a piezoelectric element 7 for detecting piezoelectricity corresponding to the Coriolis force are attached to a metal vibrating bar 20 with adhesive. The attached structure is adopted.

However, in the conventional structure as described above, the offset voltage of the detection output varies depending on the temperature due to the temperature characteristics of the adhesive. The offset voltage is the voltage output from the detection piezoelectric element when the input angular velocity is O. The variation of the offset voltage depending on the temperature is called temperature drift.In conventional vibrating gyroscopes, the temperature drift is large.
This temperature drift is an obstacle to improving the measurement accuracy of angular velocity. In addition, in the conventional structure, since the sound piece 20 is made of metal and is a conductor, the drive lead wire 8 and the detection lead wire 9 have to be attached in addition to the support wire.
These lead wires 8, 9, piezoelectric elements 6.7, and adhesive act as a load on the vibrating bar 20 as a vibrating body, reducing the Q of the vibration system using the vibrating bar 20 as a resonator. Low Q of the vibration system leads to a decrease in the sensitivity of the vibration gyro, and in addition,
Routing lead wires 8 and 9 for assembly required time and effort in the assembly process, which also became an obstacle to reducing prices.

As described above, conventional vibrating gyroscopes have problems that need to be solved regarding temperature drift, sensitivity, and the number of man-hours required for assembly.

(Means for Solving the Problems) A first means provided by the present invention to solve the above-mentioned problems is as follows: A vibrating gyroscope comprising a plurality of thin wires supported by tension, the vibrating body being a crystal or other piezoelectric body, and a driving voltage applied to the vibrating body to excite the bending vibration. An electrode and a detection t for detecting piezoelectricity corresponding to the strain generated in the vibrating body according to the angular velocity around the longitudinal axis of the vibrating body.
′! El is provided, the drive electrode and the detection electrode are made of thin films, and the thin wire serves as a conducting wire for supplying the drive voltage to the drive electrode and extracting the piezoelectricity from the detection electrode. characterized by something.

A second means provided by the present invention to solve the above-mentioned problem is as follows: first and second rectangular surfaces orthogonal to each other; a third rectangular surface orthogonal to the second rectangular surface; 1st and 3rd
a columnar body whose side surface is a fourth rectangular surface perpendicular to the rectangular surface of the columnar body; Said second and fourth
first and second thin wires stretched with a predetermined tension between the rectangular surface of the column and the casing; and third and fourth thin wires stretched between a fourth rectangular surface and the casing with a predetermined tension, and the first to fourth thin wires are stretched between the casing by tension. The angular velocity around the axis of the column is determined by detecting the Coriolis force that the column receives when exciting the bending vibration in the column. A vibrating gyroscope for detecting vibration, wherein the column is made of crystal or other piezoelectric material, a conductive thin film is provided on the first to fourth rectangular surfaces, and the first to fourth rectangular surfaces are provided with a conductive thin film. The thin films are connected to each other by a thin film conductor formed on the columnar body, the thin film on the second rectangular surface is composed of mutually independent electric currents [4a and b], and the thin film on the fourth rectangular surface is connected to each other by a thin film conductor formed on the columnar body. are mutually independent electric currents [IC and d
The electrodes a and C are connected to each other by a thin film conductor formed on the columnar body, and the first thin wire is connected to the thin film conductor formed on the columnar body on the first surface. The second, third, and fourth thin wires are connected to the thin film, and the second, third, and fourth thin wires are connected to the electrodes c, b, and d by directly contacting them, respectively.

(Function) Since the vibrating gyroscope of the present invention adopts the structure as described above, there is no member fixed with adhesive to the vibrating body (corresponding to the vibrating piece described above), and the vibrating body is made of crystal or other piezoelectric material. Since the piezoelectric body is an insulator, a special lead wire (
Therefore, in the vibrating gyroscope of the present invention, there is no temperature drift due to the temperature characteristics of the adhesive, and there is no need to attach a conductive wire to the vibrating body. There is no reduction in the Q of the vibration system due to the bonded piezoelectric element or adhesive, and there is no need for assembly work for routing lead wires during the manufacturing process.

(Example) Next, the present invention will be explained in more detail with reference to the drawings.

4 to 6 are diagrams showing the basic structure of a bending vibrator. An embodiment of the present invention is shown in FIGS. 1 to 3, but in order to facilitate the explanation of this embodiment, the bending vibrator shown in FIGS. 4 to 6 will be explained first. However, although the structure shown in FIGS. 4 to 6 can excite bending vibration in the sound bar, it does not include electrodes for piezoelectric detection.
In this state, it cannot be used as a vibrating gyro.

FIG. 4 is a developed view showing the electrodes in the bending vibrator, FIG. 5 is a perspective view conceptually showing the bending vibrator, and FIG. 6 is a conceptual view of the electrode arrangement in a cross section of the bending vibrator. FIG. The vibrating bar 10 of this bending vibrator is made of crystal, and electrodes 3a4a, 3b, and 4b made of thin films are provided on each side surface A, B, C, and D of the vibrating bar 10, respectively. The support wires la, lb, 2a and 2b have one end fixed at a position that becomes a node when bending vibration is excited in the vibrating bar 10, and electrically connect the thin film on each surface as shown in FIG. It is connected. The shaded portion in FIG. 4 is a thin film electrode. Due to the structure of this thin film, the A-plane and 0
The electrodes 3a and 3b formed on the surface are connected. Therefore, a voltage is applied to the polarity shown in Fig. 6, and the 6th
The polarity of the applied voltage is reversed at regular intervals by applying a voltage with the opposite polarity to that shown in the figure.
When C pressure is applied, the sound bar 1 made of crystal due to the piezoelectric effect
0 undergoes bending vibration in the x-z plane.

In this bending vibrator, the material of the sound piece is crystal, which is a type of piezoelectric material, and the electrode for creating an electric field in the piezoelectric material is a thin film formed on the sound piece, and the lead wire that applies voltage to the electrode is a thin film formed on the sound piece. It is characterized by the fact that it also serves as a support wire to support the sound pieces.

As mentioned above, FIGS. 1 to 3 are diagrams showing a vibrating gyroscope according to an embodiment of the present invention. FIG. 1 is an exploded view showing the electrodes in the actual example, and FIG. FIG. 3 is a perspective view conceptually showing the embodiment, and FIG. 3 is a diagram conceptually showing the electrode arrangement in a cross section of the embodiment.

This embodiment includes a vibrating bar 10 made of crystal, and electrodes 3a, 3b, 4a made of a conductive thin film formed on the side surface of the vibrating bar 10.
, 4b, 5a, 5b, and support wires Ia, Ib, 2a, 2b stretched between the casing (not shown) and a position that becomes a node when the vibrating bar 10 performs bending vibration. It is configured. The structure in which four supporting wires are stretched between the vibrating bar and the housing and the tension of the supporting wires is used to support the vibrating bar at a fixed position relative to the housing is the same as that of a general vibrating gyroscope. It is shown in Utility Model Publication No. 6247049. Also, attach the support wire to the sound piece! , that is, the position of the node of bending vibration in the sound piece is such that the total length of the sound piece is 1
As mentioned above, it is well known that the point is 0.2242 from the left and right ends.

The feature of this embodiment is that the electrode structure of the bending vibrator shown in FIGS. 4 to 6 is modified, and detection electrodes are provided in addition to the drive electrodes, and the lead wires of these electrodes also serve as support wires. It's in the structure.

The electrodes consist of drive electrodes 3a, 3b, 4a, 4b and detection electrodes 5a, 5b. The driving electrodes 3a and 3b are formed on the A side and the 0 side, respectively, and are connected to each other on the vibrating bar 10 by a thin film formed on the right end in FIG. The drive electrodes 4a and 4b are formed on the B side and the 0 side, respectively, and are connected to each other on the sound bar 10 by a thin film formed on the left end in FIG.

The detection molds i5a and 5b are formed on the B side and the 0 side, respectively.

The support wire 1a is connected to the drive electrode 3a via a thin film extending from the drive electrode 3a to the B side in the form of a protruding line. The support wire 1b is directly connected to the drive electrode 4b. Support wires 2a and 2b are detection electrodes 5a
and 5b, respectively. These supporting wires 1 a +lb, 2 a, and 2 b are soldered to the vibrating bar 10 by burning chain points.

FIG. 3(a) shows the polarity of the voltage applied to the vibrating bar 10 and the direction of the electric field generated by this voltage at the structure of the electrodes described above and the connection between these ti and the support wire. There is. In this embodiment, in order to excite bending vibration in the vibrating bar 10, an AC voltage is applied to the driving E pole, and as shown in this figure, the A side and the 0 side are made positive polarity, and the B side and D side are made negative polarity. The polarity of the applied voltage is reversed at regular intervals, such that an electric field is created in the direction shown by the arrow, and the polarity of the applied voltage is reversed at the next instant. The bending vibration is x in Figure 2.
- If there is an angular velocity around the Z axis when this bending vibration is excited, the vibrating bar 10 is distorted by the Coriolis force, and this distortion causes the vibrating bar 10 to move in the y-z plane. Vibration is generated, and piezoelectricity corresponding to the vibration is used for detection.
, 5b. FIG. 3(b) shows the arrangement of the detection electrodes, the support wires 2a and 2b, and the detection electrode 5a.
, 5b. Detection type &5a and 5
Since the phase of the piezoelectricity extracted from the vibrating bars 1o and 1o differs by 180 degrees from each other, even if the piezoelectric characteristics of the vibrating bar 1o have temperature dependence, in this embodiment, the output voltage is obtained between the detection molds [i5a and 5b]. , its temperature dependence is canceled out.

As is clear from FIGS. 1 and 3, in this embodiment, the support wires la, lb, and 2a.

Since the wires 2b are connected to drive electrodes and detection electrodes having different polarities, only four support wires can serve as lead wires for applying a drive voltage and extracting a detection voltage. What made it possible for the support wire to have all the functions of a lead wire is that the sound bar is made of an insulator called crystal, and the drive electrode and detection electrode are placed on the B and D sides of the sound bar. This is due to the addition of

In the embodiment described above, since no adhesive is included in the load of the vibrating bar 10 as a vibrating body, there is no temperature drift in the input/output characteristics. Since there is no piezoelectric element or adhesive fixed to the vibrating bar 10, the load on the vibrating bar 10 is small.
Therefore, the Q of the vibration system with the vibrating bar 10 as a resonator is the 7th
Since the Q is larger than the Q of the vibration system in the conventional vibrating gyroscope shown in the figure, this embodiment is also superior to the conventional vibrating gyroscope in terms of sensitivity. Furthermore, the absence of lead wires other than the support wires has the effect of significantly reducing the number of man-hours required in the assembly process of this embodiment compared to that of the conventional example.

In addition, in the embodiment described above, the driving electrodes 3a, 3b
has a pattern in which rectangular thin films are connected by linear thin films, but these electrodes may also be rectangular with thin films formed over almost the entire area of the A and 0 sides as shown in Figure 4.
However, as shown in Figure 1, the drive type '44F! 3 a,
By making the pattern 3b correspond to the pattern of the driving poles 4a and 4b, the driving voltage f! The influence of the electric fields 3a and 3b on the detection electrodes 5a and 5b can be reduced.

Further, in the above-described embodiment, the vibrating bar 10 is made of quartz, but the present invention can be practiced even if the vibrating body is made of not only quartz but also other piezoelectric materials.

(Effects of the Invention) As described above in detail with reference to the embodiments, according to the present invention, it is possible to provide a vibrating gyroscope that has small temperature drift, high sensitivity, and can be assembled with a small number of man-hours.

[Brief explanation of the drawing]

1 to 3 are diagrams showing one embodiment of the present invention,
Fig. 1 is a developed view showing the electrodes in the embodiment, Fig. 2 is a perspective view conceptually showing the embodiment, and Fig. 3 is a conceptual diagram showing the electrode arrangement in a cross section of the embodiment. It is a diagram. 4 to 6 are diagrams showing a bending vibrator mentioned to facilitate the explanation of the embodiment, and FIG. 4 is a diagram showing the bending vibrator! FIG. 5 is a perspective view conceptually showing the bending vibrator, and FIG. 6 is a diagram conceptually showing the electrode arrangement in a cross section of the bending vibrator. FIG. 7 is a perspective view conceptually showing a conventional sound piece-shaped vibrating gyroscope. 1 a, 1 b, 2a, 2b - support wire, 3a. 3b, 4a, 4b...driving electrode, 5a,
5b--detection electrode, 6--driving pressure @ cable, 7-
... Piezoelectric element for detection, 8... Lead wire for drive, 9...
・Detection lead wire, 10.20... sound piece.

Claims (2)

[Claims] (1) A vibrating gyroscope comprising a columnar vibrating body with a rectangular cross section and a plurality of thin wires that support the nodal points of bending vibration in this vibrating body with tension, wherein the vibrating body is a crystal or other piezoelectric material. The vibrating body includes a driving electrode to which a driving voltage for exciting the bending vibration is applied, and a piezoelectric material that corresponds to the strain generated in the vibrating body according to the angular velocity around the longitudinal axis of the vibrating body. A detection electrode for detection is provided, the drive electrode and the detection electrode are made of thin films, and the thin wire is a conducting wire that supplies the drive voltage to the drive electrode and extracts the piezoelectricity from the detection electrode. A vibrating gyro characterized by being used for both. (2) first and second rectangular surfaces that are orthogonal to each other; a third rectangular surface that is orthogonal to the second rectangular surface; and a fourth rectangular surface that is orthogonal to the first and third rectangular surfaces; a columnar body having side surfaces thereof, and said second and fourth nodes at positions that become first nodes when said columnar body undergoes bending vibration in a plane perpendicular to said first rectangular surface.
first and second thin wires stretched with a predetermined tension between the rectangular surface of the column and the casing; and third and fourth thin wires stretched between a fourth rectangular surface and the casing with a predetermined tension, the first to fourth thin wires being stretched against the casing by tension. The columnar body is held in a predetermined position, and the angular velocity around the axis of the columnar body is detected by detecting the Coriolis force that the columnar body receives when exciting the bending vibration in the columnar body. In the vibrating gyroscope, the pillar body is made of crystal or other piezoelectric material, a conductive thin film is provided on the first to fourth rectangular surfaces, and the thin film on the first and third rectangular surfaces is They are connected to each other by a thin film conductor formed on the columnar body, the thin film on the second rectangular surface consists of mutually independent electrodes a and b, and the fourth
The thin film on the rectangular surface consists of mutually independent electrodes c and d, the electrodes a and c are connected to each other by a thin film conductor formed on the columnar body, and the first thin wire is formed on the columnar body. A thin film conductor formed on the first surface is connected to the thin film on the first surface, and the second, third and fourth thin wires are in direct contact with and connected to the electrodes c, b and d, respectively. A vibrating gyro characterized by: