JPH0479419B2 - - Google Patents
Info
- Publication number
- JPH0479419B2 JPH0479419B2 JP57168000A JP16800082A JPH0479419B2 JP H0479419 B2 JPH0479419 B2 JP H0479419B2 JP 57168000 A JP57168000 A JP 57168000A JP 16800082 A JP16800082 A JP 16800082A JP H0479419 B2 JPH0479419 B2 JP H0479419B2
- Authority
- JP
- Japan
- Prior art keywords
- acceleration
- load
- piezoelectric substrate
- comb
- saw element
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000001133 acceleration Effects 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 11
- 238000013001 point bending Methods 0.000 claims description 11
- 239000000758 substrate Substances 0.000 claims description 11
- 238000010897 surface acoustic wave method Methods 0.000 claims description 3
- 238000005452 bending Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000010355 oscillation Effects 0.000 description 3
- 238000011068 loading method Methods 0.000 description 2
- 230000008602 contraction Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
- G01P15/097—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by vibratory elements
- G01P15/0975—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by vibratory elements by acoustic surface wave resonators or delay lines
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Description
【発明の詳細な説明】
本発明は、表面音響波（SAWと略記する。）素
子を利用した加速度センサに関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acceleration sensor using a surface acoustic wave (abbreviated as SAW) element.
加速度センサ（振動センサ）としては、抵抗線
歪計ピエゾ素子等々のすべに確立した技術があ
る。 As acceleration sensors (vibration sensors), there are established technologies such as resistance wire strain meters and piezo elements.
本発明は、SAW素子を利用することによりこ
れらのセンサに比して小型化、低価格化をはか
り、テレメータの搬送波周波数の発振要素と兼用
させることも可能な加速度センサを提供しようと
するものである。 The present invention aims to provide an acceleration sensor that is smaller and cheaper than these sensors by using a SAW element, and that can also be used as an oscillation element for the carrier wave frequency of a telemeter. be.
例えば、切削加工時における工具損傷、工具摩
耗などの検出には、できるだけ小型で信頼性のあ
る振動センサが必要であり、しかも各切刃毎に装
着するためできる限り安価であることが望ましい
が、本発明の加速度センサは、このような工具損
傷等の検出に有効であるばかりでなく、一般的な
振動測定、特にフイールドテストや種々の回転機
器の振動モニタとして有効なものである。 For example, to detect tool damage, tool wear, etc. during cutting, a vibration sensor that is as small and reliable as possible is required, and since it is attached to each cutting edge, it is desirable that it be as inexpensive as possible. The acceleration sensor of the present invention is not only effective for detecting such tool damage, but also for general vibration measurement, particularly for field tests and vibration monitoring of various rotating equipment.
而して、上記SAW素子を利用した小型、低廉
な加速度センサを得るに際し、本発明者らは、
種々の予備的な実験を行い、それにより、第３図
及び第４図により後述するように、SAW素子に
対して３点曲げによる曲げ荷重を加えた場合に
は、圧電性基板に作用する応力が不均一になるた
め、種々の問題が生じることを確かめた。また、
その原因を追求することにより、略均一応力とな
る荷重方式により問題を解決できることを確かめ
た。 Therefore, in order to obtain a compact and inexpensive acceleration sensor using the above-mentioned SAW element, the present inventors
We conducted various preliminary experiments and found that when a bending load is applied to the SAW element by three-point bending, the stress acting on the piezoelectric substrate is It was confirmed that various problems occur due to non-uniformity. Also,
By investigating the cause of this problem, we confirmed that the problem could be solved by a loading method that produces approximately uniform stress.
本発明は、かかる知見に基づいて完成したもの
であり、即ち、圧電性基板の表面にくし状電極を
設置し、入力端子からの上記電極への入力信号に
よつて圧電性基板に生じた表面波がくし状電極に
よつて順次反射され、それに伴う出力が出力端子
にあらわれる表面音響波素子を用い、この素子に
対して被測定加速度に伴う荷重を負荷する手段と
して、素子の両端を支持してその両端に近い位置
に加速度発生用質量を取付ける４点曲げ方式、ま
たは被測定加速度に伴う荷重の分布がそれと同程
度に均一化されるように素子に対する荷重点を配
設する方式を用いたことを特徴とするものであ
る。 The present invention was completed based on this knowledge, that is, a comb-shaped electrode is installed on the surface of a piezoelectric substrate, and the surface generated on the piezoelectric substrate by an input signal to the electrode from the input terminal. A surface acoustic wave element is used in which waves are sequentially reflected by comb-shaped electrodes, and the resulting output appears at the output terminal, and both ends of the element are supported as a means of applying a load associated with the acceleration to be measured to this element. A four-point bending method is used in which the mass for generating acceleration is attached to a position close to both ends, or a method is used in which load points are placed on the element so that the distribution of the load accompanying the measured acceleration is made uniform to the same degree. It is characterized by:
以下、図面を参照して本発明の実施例について
詳述する。 Embodiments of the present invention will be described in detail below with reference to the drawings.
本発明の加速度センサにおいて用いるSAW素
子は、LiNbO3、LiTaO3、BaTiO3、PbTiO3等の圧
電性基板の表面にくし状電極を設置して表面波を
発生させるものであり、一般にTV回路等のフイ
ルタとして用いられている。 The SAW element used in the acceleration sensor of the present invention has comb-shaped electrodes on the surface of a piezoelectric substrate such as L i N b O 3 , L i T a O 3 , B a T i O 3 , P b T i O 3 , etc. It is installed to generate surface waves, and is generally used as a filter in TV circuits, etc.
第１図はこのSAW素子の構成を示すものであ
り、１は圧電性基板、２はくし状電極（150〜200
本）、３は入力端子、４は出力端子を示している。 Figure 1 shows the configuration of this SAW element, where 1 is a piezoelectric substrate, 2 is a comb-shaped electrode (150 to 200
3 indicates an input terminal, and 4 indicates an output terminal.
このSAW素子においては、入力端子３から入
力した信号によつて圧電性基板１の表面に生じた
表面波が左右に進むが、多数のくし状電極によつ
て順次反射され、出力端子４に出力があらわれ
る。このとき、くし状電極２のピツチＰが表面波
の半波長λ／２に合致すると、ほとんど完全に反
射され、出力端子４にほぼ全出力が出る。これは
一種の直列共振素子であり、その等価回路は第２
図のようになる。共振のＱは数千〜数万が可能で
ある。なお、第２図においてC12は入出力端子３，
４間の容量である。 In this SAW element, a surface wave generated on the surface of the piezoelectric substrate 1 by a signal input from the input terminal 3 propagates left and right, but is sequentially reflected by a large number of comb-shaped electrodes and output to the output terminal 4. appears. At this time, when the pitch P of the comb-shaped electrode 2 matches the half wavelength λ/2 of the surface wave, the wave is almost completely reflected and almost the entire output is output to the output terminal 4. This is a type of series resonant element, and its equivalent circuit is the second
It will look like the figure. The resonance Q can range from several thousand to several tens of thousands. In addition, in Fig. 2, C 12 is the input/output terminal 3,
The capacity is between 4 and 4.
而して、第１図のSAW素子において、圧電性
基板１としてLiTaO3（音速≒3250ｍ／ｓ）を用
い、ピツチＰを約21μｍとしたとき、77.4MHzの
搬送波が発振される。 Therefore, in the SAW element shown in Fig. 1, when L i T a O 3 (sound velocity ≒ 3250 m/s) is used as the piezoelectric substrate 1 and the pitch P is approximately 21 μm, a carrier wave of 77.4 MHz is oscillated. .
このようなSAW素子に曲げ荷重を加えると、
応力によつてピツチＰが伸縮するため、直列共振
周波数s、並列共振周波数p、通過特性などが変
化する。この効果は加速度による荷重でも同様で
あり、従つて加速度センサとして動作させること
が可能である。 When a bending load is applied to such a SAW element,
Since the pitch P expands and contracts due to stress, the series resonance frequency s, parallel resonance frequency p, passing characteristics, etc. change. This effect is the same for loads caused by acceleration, and therefore it is possible to operate it as an acceleration sensor.
第３図及び第４図は、それらの図中に示すよう
にSAW素子に対して３点曲げによる曲げ荷重を
加えた場合における特性の変化を示すものである
が、実際の周波数変化はピツチＰの伸縮から求め
た値より大きい。即ち、抵抗線歪計の場合と同様
にゲージフアクタがある。そのゲージフアクタ
は、この３点曲げによる曲げ荷重の場合、圧電性
基板１に作用する応力が不均一であるため、平均
応力に対し約4.33であつた。また、３点曲げ方式
では、見かけの直列共振周波数sの変化は飽和的
でリニアリテイが劣る。これは、荷重増加による
通過特性の劣化が原因である。このような効果
は、歪み不均一に伴うピツチＰの不均一に基づ
き、表面波反射のコヒーレンスが乱れるためと考
えられる。 Figures 3 and 4 show the changes in characteristics when a bending load is applied to the SAW element by three-point bending as shown in those figures, but the actual frequency change is due to the pitch P. is larger than the value calculated from the expansion and contraction of. That is, there is a gauge factor as in the case of a resistance wire strain meter. In the case of the bending load due to this three-point bending, the gauge factor was about 4.33 with respect to the average stress because the stress acting on the piezoelectric substrate 1 was non-uniform. Furthermore, in the three-point bending method, the change in the apparent series resonance frequency s is saturated and the linearity is poor. This is due to the deterioration of the passing characteristics due to the increase in load. This effect is thought to be due to the fact that the coherence of the surface wave reflection is disturbed due to the non-uniformity of the pitch P due to the non-uniformity of the distortion.
従つて、本発明においては、SAW素子に対し
て略均一応力となる荷重方式によつて被測定加速
度に伴う荷重を負荷し、そのため第５図に例示す
るような荷重負荷手段が採用される。この荷重負
荷手段は、両端を支持したSAW素子１０に対し
てその両端に近い位置において加速度発生用質量
１１を取付け、上述の３点曲げ方式に対して４点
曲げ方式を採用し、振動加速度に伴う荷重が
SAW素子１０に略均一応力として作用するよう
にしたものである。 Therefore, in the present invention, a load associated with the acceleration to be measured is applied to the SAW element by a loading method that provides a substantially uniform stress, and therefore a load applying means as illustrated in FIG. 5 is employed. This load applying means attaches acceleration generating masses 11 at positions close to both ends of the SAW element 10, which supports both ends, and adopts a four-point bending method instead of the three-point bending method described above. The load involved
This is designed to act as a substantially uniform stress on the SAW element 10.
第６図はこの４点曲げ方式における特性変化を
示すもので、リニアリテイ、通過特性とも良好で
ある。なお、この場合のゲージフアクタは約1.8
であつた。 FIG. 6 shows changes in characteristics in this four-point bending method, and both linearity and passing characteristics are good. In addition, the gauge factor in this case is approximately 1.8
It was hot.
なお、SAW素子に対して被測定加速度に伴う
荷重を負荷する手段としては、上述したように、
素子の両端を支持してその両端に近い位置に加速
度発生用質量を取付ける４点曲げ方式ばかりでな
く、被測定加速度に伴う荷重の分布がそれと同程
度に均一化されるように素子に対する荷重点を配
設する適宜方式を用いることができる。 As mentioned above, as a means of applying a load associated with the measured acceleration to the SAW element,
In addition to the four-point bending method in which both ends of the element are supported and acceleration generating masses are attached to positions close to both ends, the load points on the element are adjusted so that the distribution of the load accompanying the measured acceleration is equally uniform. An appropriate method for arranging can be used.
また、第７図Ａ〜Ｃは上記SAW素子をテレメ
ータ等の搬送波周波数の発振要素と兼用する場合
の回路構成を示している。 Further, FIGS. 7A to 7C show a circuit configuration in which the above-mentioned SAW element is also used as a carrier frequency oscillation element of a telemeter or the like.
以上に詳述したところから明らかなように、本
発明によれば、小型、安価で、電力消費が少な
く、しかもテレメータを兼ねたものとして構成で
きる加速度センサを得ることができる。 As is clear from the detailed description above, according to the present invention, it is possible to obtain an acceleration sensor that is small, inexpensive, consumes little power, and can also be configured as a telemeter.
第１図は本発明において用いるSAW素子の平
面図、第２図は上記SAW素子の等価回路に関す
る説明図、第３図及び第４図はSAW素子の３点
曲げ方式の荷重による特性変化を示す線図、第５
図は本発明に係る加速度センサの実施例を示す側
断面図、第６図はその特性を示す線図、第７図Ａ
〜Ｃは上記SAW素子を搬送波周波数の発振要素
として用いる場合の回路構成図である。
１……圧電性基板、２……くし状電極、３……
入力端子、４……出力端子、１０……SAW素子、
１１……質量。
Fig. 1 is a plan view of the SAW element used in the present invention, Fig. 2 is an explanatory diagram of the equivalent circuit of the above SAW element, and Figs. 3 and 4 show changes in characteristics of the SAW element due to load in the three-point bending method. Diagram, 5th
The figure is a side sectional view showing an embodiment of the acceleration sensor according to the present invention, FIG. 6 is a diagram showing its characteristics, and FIG. 7A
-C are circuit configuration diagrams when the above-mentioned SAW element is used as an oscillation element of a carrier wave frequency. 1...Piezoelectric substrate, 2...Comb-shaped electrode, 3...
Input terminal, 4...output terminal, 10...SAW element,
11...Mass.
Claims (1)
力端子からの上記電極への入力信号によつて圧電
性基板に生じた表面波がくし状電極によつて順次
反射され、それに伴う出力が出力端子にあらわれ
る表面音響波素子を用い、この素子に対して被測
定加速度に伴う荷重を負荷する手段として、素子
の両端を支持してその両端に近い位置に加速度発
生用質量を取付ける４点曲げ方式、または被測定
加速度に伴う荷重の分布がそれと同程度に均一化
されるように素子に対する荷重点を配設する方式
を用いたことを特徴とする加速度センサ。1 A comb-shaped electrode is installed on the surface of a piezoelectric substrate, and the surface waves generated on the piezoelectric substrate by the input signal from the input terminal to the electrode are sequentially reflected by the comb-shaped electrode, and the resulting output is output. A four-point bending method uses a surface acoustic wave element that appears at the terminal, and supports both ends of the element and attaches an acceleration generating mass to a position close to each end, as a means of applying a load associated with the acceleration to be measured to this element. , or an acceleration sensor characterized by using a method of arranging load points on the element so that the distribution of the load accompanying the acceleration to be measured is made uniform to the same extent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16800082A JPS5957166A (en) | 1982-09-27 | 1982-09-27 | Acceleration sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16800082A JPS5957166A (en) | 1982-09-27 | 1982-09-27 | Acceleration sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5957166A JPS5957166A (en) | 1984-04-02 |
| JPH0479419B2 true JPH0479419B2 (en) | 1992-12-15 |
Family
ID=15859938
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16800082A Granted JPS5957166A (en) | 1982-09-27 | 1982-09-27 | Acceleration sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5957166A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002122614A (en) | 2000-10-12 | 2002-04-26 | Murata Mfg Co Ltd | Acceleration sensor |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5364045A (en) * | 1976-11-19 | 1978-06-08 | Hitachi Ltd | Strain converer |
| JPS5414285A (en) * | 1977-07-01 | 1979-02-02 | Thomson Csf | Elastic surface wave acceleration seismometer |
-
1982
- 1982-09-27 JP JP16800082A patent/JPS5957166A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5364045A (en) * | 1976-11-19 | 1978-06-08 | Hitachi Ltd | Strain converer |
| JPS5414285A (en) * | 1977-07-01 | 1979-02-02 | Thomson Csf | Elastic surface wave acceleration seismometer |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5957166A (en) | 1984-04-02 |
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