JPH07110337A - Angular velocity sensor - Google Patents

Abstract

PURPOSE:To obtain an angular velocity sensor device being excellent in temperature characteristic in a wide temperature range and inexpensive. CONSTITUTION:First and second vibration units 41 and 51 are constructed so 'that they are parallel to each other along axis of detection, and first and second elements 43 and 53 for driving and first and second elements 45, 46, 55 and 56 for detection are disposed on the same planes of the first and second vibration units 41 and 51 respectively. By constructing the elements on the same plane in this way, the angular velocity sensor being excellent in wide temperature characteristic can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity sensor using vibration.

[0002]

2. Description of the Related Art Conventionally, a mechanical gyro has been mainly used as a method for knowing the direction of a moving object such as an airplane or a ship by using a gyroscope using an angular velocity sensor as an inertial navigation device. However, since it is a mechanical type, the size of the device is large, the cost is high, and it is difficult to apply it to a device that requires miniaturization.

On the other hand, there are piezoelectric and electromagnetic vibrating angular velocity sensor devices for vibrating an object without using a rotational force and detecting the Coriolis force from the detection element by the vibration.
These are vibrations in which the motion of the mass that constitutes the gyro is not a constant speed motion, so when the angular velocity changes, the Coriolis force is generated as a vibration torque of the mass frequency. The principle of the vibrating angular velocity sensor device is to measure the angular velocity by detecting the vibration caused by this torque, and various angular velocity sensor devices using a piezoelectric element have been proposed (Journal of the Japan Aerospace Society, Vol. 23, No. 23). 257, pages 239-350).

A conventional angular velocity sensor will be described below with reference to the drawings. FIG. 10 is a perspective view of an angular velocity sensor in a conventional example. In FIG. 10, reference numerals 1 and 2 denote a pair of left and right symmetrical first and second vibrating units formed by bending a metal plate mainly composed of Fe and Ni. The first and second vibrating units 1 and 2 are With a structure that integrates the drive unit and the detection unit,
In addition, the drive unit and the detection unit are arranged orthogonally so as to face each other in the same direction. Reference numerals 1a and 2a denote bent portions that are bent at the centers of the vibrating members 1 and 2.
The upper part of a and 2a serves as a detection part, and the lower part serves as a drive part. Reference numerals 3, 4, 5, 6 are piezoelectric elements, which are formed by providing Ag electrodes on both surfaces of the piezoelectric ceramic. A metal block 7 holds a pair of left and right vibrating members 1 and 2 in parallel. 8 is a support rod, a metal block 7
Of the vibrating members 1 and 2 and supports the entire tuning fork portion. Reference numeral 9 is a terminal base for fixing the support rod 8, and mainly Fe is used for lead terminals 10, 11, 12, 1
3, 14, 15 and the supporting rod 8 are insulated glass 16, 17,
It is planted by interposing it on 18, 19, 20, 21, 21. Reference numerals 10, 11, 12, and 13 are lead terminals, which are terminals that lead out electric signals from the piezoelectric elements 3, 4, 5, and 6 at four locations to the outside. Reference numerals 23, 24, 25 and 26 are lead wires, which are piezoelectric elements 3, 4, 5, 6 and lead terminals 10, 11,
12 and 13 are connected. 27 is a can cap, which is joined to the terminal base 9 by welding to form an angular velocity sensor.

[0005]

However, in the above-mentioned conventional structure, the metal plates are bent so that the driving parts 3 and 4 and the detecting parts 5 and 6 are arranged orthogonally so as to face each other in the same direction. Since the first and second vibrating units 1 and 2 are configured as an integrated sensor unit, when a temperature change is applied, the detection unit and the drive unit move in a bent portion, and the orthogonal angle changes. In addition, there is a problem that a sensor with a small offset output fluctuation cannot be obtained in a wide temperature range. In addition, when the vibrating member is formed by cutting a metal block in order to obtain high accuracy with good temperature characteristics and without changing the orthogonal angle, there is a problem that the manufacturing cost increases.

An object of the present invention is to solve the above conventional problems and to provide an inexpensive angular velocity sensor having excellent temperature characteristics in a wide temperature range.

[0007]

In order to solve this problem, the angular velocity sensor of the present invention comprises first and second vibrating units configured to be parallel to each other along a detection axis,
A configuration including first and second driving elements and first and second sensing elements, which are respectively arranged on the same plane on either the front surface or the back surface of the first and second vibration units, is provided. Have

[0008]

With this configuration, the drive unit and the detection unit are formed on the same plane by using the piezoelectric element, and the vibration signal component orthogonal to the vibration direction is detected on the same plane by vibrating along the surface of the piezoelectric element. The present invention provides an angular velocity sensor having excellent temperature characteristics in a wide temperature range.

[0009]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of an angular velocity sensor according to the present invention, and FIG. 2 is an enlarged view of a vibration unit of the angular velocity sensor according to the present invention. The same parts as those in the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted. 1 and 2, 4
Reference numeral 0 is a detection axis, and 41 and 51 are a pair of symmetrical first and second vibrating units composed of piezoelectric elements in which electrodes are provided on both sides of a vibrating plate mainly composed of Fe and Ni. It is configured to be parallel to each other along the axis 40. 45 and 46 are first detection elements, and 55 and 56 are second
Detecting element, 43 is a first driving element, and 53 is a second driving element, which are arranged on the same plane as the first and second vibrating units 41 and 51 by being electrode-formed and polarized. Has been done. Reference numeral 8 is a support rod, which is inserted into a hole (not shown) in the center of the terminal base 9 and is used for the first and second vibrating units 4
It supports the entire tuning fork part consisting of 1,51. The terminal base 9 is mainly composed of Fe and lead terminals 10, 11,
Insulating glass 12 and 13, 14 and 15 and support rod 8
6,17,18,19,20,21,22 are interposed,
It is being planted. Reference numerals 10, 11, 12, and 13 denote lead terminals that lead out electric signals from the piezoelectric element to the outside. Lead wires 23, 24, 25, and 26 connect the piezoelectric element and the lead terminals 10, 11, 12, and 13. A can cap 27 is joined to the terminal base 9 by welding to form an angular velocity sensor.

FIG. 3 is an enlarged view of the first vibrating unit of the present invention. In FIG. 3, reference numeral 41 denotes a first vibrating unit, which has a first driving element 43 at the center and first sensing elements 45 and 46 at both ends on the same plane of the first vibrating unit 41. There is. The first driving elements 43 and 44 and the first sensing elements 45 and 46 are electrodes and have polarizations in opposite directions and in the thickness direction for locally expanding and contracting by applying an electric field on the same plane. Is polarized to
In this embodiment, one of the first driving element 43 and the first driving element 43
Detection elements 45 and 46 are positive, and the first drive element 4
The other of 3 is negatively polarized. Here, “+” and “−” in the figure indicate polarization directions. The second vibrating unit is also configured in the same manner as the first vibrating unit.

The operation of the angular velocity sensor configured as described above will be described below with reference to the drawings. FIG. 4 is a block diagram of the sensor means driving circuit of the present invention. Reference numeral 61 denotes a charge amplifying means, which converts a detection charge signal generated from the first detection elements 45 and 46 of the vibration unit into a detection voltage signal by applying rotation (angular velocity) to the central axis of the sensor means. Reference numeral 62 denotes an oscillating means, which outputs a drive synchronizing signal from the detected charge signal generated from the first driving elements 43 and 44 of the first vibrating unit. Reference numeral 63 is a synchronous rectification means, which applies the detection voltage signal from the charge amplification means 61 to the oscillation means 6
Synchronous detection and rectification are performed by the drive synchronization signal which is the output of 2 and an angular velocity rectification signal is output. Reference numeral 64 is a low-pass filter means, which receives the angular velocity rectification signal from the synchronous rectification means and smoothes it to obtain angular velocity signal information.

It should be noted that, as shown in FIGS. 5 and 6, the configuration of the U-shaped vibration unit, and as shown in FIG. 8, the piezoelectric elements are individually attached to the left and right of the tuning fork, and the drive section and the detection section are integrated. However, this is the same as the present embodiment.

Further, even if the first and second sensing elements are arranged on either the front surface or the back surface of the first and second vibrating units, they are the same as in this embodiment.

(Embodiment 2) Another embodiment of the present invention will be described below with reference to the drawings.

FIG. 7 is an enlarged view of a vibrating unit according to another embodiment of the present invention. The same parts as those in the conventional example and the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. In FIG. 7, 71 and 72 are a pair of symmetrical first and second vibrating units composed of piezoelectric elements in which electrodes are provided on both sides of a vibrating plate mainly composed of Fe and Ni. The first drive element 74, the second drive element 75, and the first detection units 45 and 46 and the second detection units 55 and 56 at both ends are provided, and the first and second drive units are provided. The configuration is such that 71, 72 are offset from the center in the vertical direction. The first drive element 74, the second drive element 75, the first detection elements 45 and 46, and the second detection elements 55 and 56 are electrodes and locally formed on the same surface by applying an electric field. Are polarized in opposite directions and in the thickness direction.

The construction of the U-shaped sensor means as shown in FIGS. 8 and 9 is similar to that of this embodiment.

[0018]

As described above, according to the present invention, the first and second vibrating units configured to be parallel to each other along the detection axis, and the front or back surface of the first and second vibrating units. When the vibrating unit is vibrated by using the angular velocity sensor including the first and second driving elements and the first and second sensing elements respectively arranged on the same plane of Since the direction of drive vibration and the direction of the detection unit are formed on the same plane, unnecessary signals to the detection unit are reduced. Further, by configuring the detecting element and the driving element on the same plane, it is possible to provide an angular velocity sensor in a wide temperature range and with little characteristic change in response to a sudden temperature change. Further, since the structure is simple, mass productivity is excellent and cost reduction can be achieved.

[Brief description of drawings]

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

FIG. 2 is an enlarged view of a vibration unit, which is the main part of the same.

FIG. 3 is an enlarged view of a first vibrating unit, which is the main part of the same.

FIG. 4 is a block diagram of a vibration unit, which is the main part of the same.

FIG. 5 is a perspective view of a U-shaped vibration unit, which is a main part of the other embodiment.

FIG. 6 is a perspective view of another U-shaped vibration unit.

FIG. 7 is an enlarged view of a vibration unit according to another embodiment.

FIG. 8 is a perspective view of a U-shaped vibrating unit according to another embodiment.

FIG. 9 is a perspective view of another U-shaped vibrating unit.

FIG. 10 is a perspective view of an angular velocity sensor in a conventional example.

[Explanation of symbols]

 41 first vibrating unit 51 second vibrating unit 45,46 first sensing element 43 first driving element 53 second driving element 55,56 second sensing element

Claims (4)

[Claims] 1. A first vibration unit and a second vibration unit configured to be parallel to each other along a detection axis, and one of the front and back surfaces of the first vibration unit and the second vibration unit on the same plane. An angular velocity sensor characterized in that a first and a second driving element and a first and a second sensing element are respectively arranged in the. 2. The angular velocity sensor according to claim 1, wherein the first or second detecting element and the driving element have electrodes and polarized directions are different from each other. 3. The angular velocity sensor according to claim 1, wherein a detecting element is arranged at both ends of the vibrating unit, and a driving element is arranged at a central portion. 4. The angular velocity sensor according to claim 1, wherein the first and second vibrating units are substantially U-shaped.