SU918857A1

SU918857A1 - Piezoelectric acceleration meter

Info

Publication number: SU918857A1
Application number: SU802867586A
Authority: SU
Inventors: Полина Львовна Закс; Валерий Иосифович Зархин
Original assignee: Предприятие П/Я В-2962
Priority date: 1980-01-09
Filing date: 1980-01-09
Publication date: 1982-04-07

Description

Союз Советских Социалистических Республик Union of Soviet Socialist Republics О ПИ С А Н И Е ИЗОБРЕТЕНИЯ К АВТОРСКОМУ СВИДЕТЕЛЬСТВУ DESCRIPTION OF THE INVENTION TO COPYRIGHT CERTIFICATE ш, 918857 w, 918857 Я® I® (61) Дополнительное к авт. свид-ву - (61) Additional to author certificate woo - т t (22)Заявлено 09.01.80 (21) 2867586/18-10 (22) Stated 09/01/80 (21) 2867586 / 18-10 (51 )М. Кл! (51) M. Kl! с присоединением заявки № with joining application no. .G 01 Р 15/09 .G 01 P 15/09 |ЬсударсткняыЙ комитет | Bylaws Committee (23)Пркоритет « .’ (23) The prosecution is “.’ СССР USSR по демм изобретений by demme of inventions Опубликовано 07.04.82. Бюллетень № 13 Published on April 7, 2018. Bulletin No. 13 (53)УДК 53U768 (53) UDC 53U768 к открытий to discoveries Дата опубликования описания 07.0402 Date published description 07.0402 (088.8) (088.8)

(72) Авторы изобретения(72) The inventors

Н. Л.Закс и В.И.Зархин (71) ЗаявительN. L. Zaks and V.I. Zarkhin (71) Applicant

(54) ПЬЕЗОЭЛЕКТРИЧЕСКИЙ АКСЕЛЕРОМЕТР(54) PIEZO ELECTRIC ACCELEROMETER

Изобретение относится к измерению· параметров движения, в частности к пьезоэлектрическим акселерометрам, и может быть использовано для измерения параметров вибраций.The invention relates to the measurement of · motion parameters, in particular to piezoelectric accelerometers, and can be used to measure vibration parameters.

Известны пьезоэлектрические аксе- ⁵лерометры с пьезоэлементами, установленными между инерционной массой и корпусом (1) и [2].Known piezoelectric akse- ⁵ lerometry with piezo elements mounted between the inertial mass and the housing (1) and [2].

Известные акселерометры имеют относительно низкую чувствительность и подвержены влиянию боковых ускорений. Пьезоэлектрические акселерометры с консольными чувствительными элементами обладают относительно низкой ударной прочностью и ограниченным ¹частотным диапазоном работы.Known accelerometers have a relatively low sensitivity and are affected by lateral accelerations. Piezoelectric accelerometers with cantilever sensors have a relatively low impact strength and a limited ¹ frequency range of operation.

Наиболее близким по технической сущности и достигаемому результату является акселерометр, содержащий закрепленный в корпусе посредством стержня чувствительный элемент, выполненный в виде инерционной массы, размещенной по периферии плоской {мембраны,. пьезоэлектрического элемента, установленного на мембране·, центральная часть которой жестко скреплена со стержнем [3].The closest in technical essence and the achieved result is an accelerometer containing a sensing element fixed in the housing by means of a rod, made in the form of an inertial mass located on the periphery of a flat {membrane. a piezoelectric element mounted on a membrane ·, the central part of which is rigidly bonded to the rod [3].

Цель изобретения - повышение чувствительности акселерометра.The purpose of the invention is to increase the sensitivity of the accelerometer.

Для достижения цели в акселерометре инерционная масса выполнена в виде двух полых соосных цилиндров, имеющих равные по толщине стенки и расположенных с противоположных сторон мембраны, причем, по крайней мере, один из цилиндров является пьезч* элементом, а толщина мембраны t связана со средним радиусом пьезоэлемента Rep и толщиной сА стенки цилиндра соотношением t < S 3Rppd4 · . На фиг. 1 представлена упрощенная конструктивная схема пьезоэлектрического акселерометра; на фиг. 2 - вариант акселерометра с двумя пьезоэлементами.To achieve the goal in the accelerometer, the inertial mass is made in the form of two hollow coaxial cylinders having equal wall thickness and located on opposite sides of the membrane, and at least one of the cylinders is a piezo * element, and the membrane thickness t is connected with the average radius of the piezoelectric element Rep and thickness сА of the cylinder wall with the relation t <S 3Rppd4 ·. In FIG. 1 shows a simplified structural diagram of a piezoelectric accelerometer; in FIG. 2 - version of the accelerometer with two piezoelectric elements.

Акселерометр содержит основание 1, инерционную массу в виде двух ци*The accelerometer contains a base 1, the inertial mass in the form of two qi *

91 линдров 2 и 3, установленных на противоположных с^хоронах мембраны 4 из упругого материала и жестко скрепленных с ней торцами. Мембрана 4 жестко связана по центру с основанием. Основание 1, в зависимости от способа закрепления на объекте измерения, может быть выполнено либо сплошным (фиг. 1), либо в виде цилиндрической трубки (фиг.· 2), соосно установленной с цилиндрами 2 и 3. Цилиндр 2 выполнен из п.ьезокерамики. Акселерометр снабжен защитным кожухом 5.91 cylinders 2 and 3, mounted on the membrane 4 opposite to ^the burials of elastic material and rigidly fastened with ends. Membrane 4 is rigidly connected in the center to the base. The base 1, depending on the method of fixing on the measurement object, can be either solid (Fig. 1), or in the form of a cylindrical tube (Fig. · 2), coaxially mounted with cylinders 2 and 3. Cylinder 2 is made of ceramic. . The accelerometer is equipped with a protective casing 5.

Акселерометр работает следующим об>/ 4 рометра при увеличении его чувствительности .The accelerometer works as follows about> 4 meters with an increase in its sensitivity.

На фиг. 2 представлена упрощенная конструктивная схема акселерометра, в которой инерционная масса выполнена целиком из пьезокерамики и состоит из двух пьезокерамических цилиндров/ Симметрично закрепленных на обоих сторонах мембраны, выполненной, например, из титана.In FIG. Figure 2 shows a simplified structural diagram of an accelerometer in which the inertial mass is made entirely of piezoceramics and consists of two piezoceramic cylinders / Symmetrically fixed on both sides of a membrane made, for example, of titanium.

Кроме повышения чувствительности при измерении ускорения, конструкция чувствительного элемента позволяет уменьшить массу и габариты предлагаемого акселерометра.In addition to increasing sensitivity when measuring acceleration, the design of the sensitive element allows to reduce the mass and dimensions of the proposed accelerometer.

разом.at once.

При наличии ускорения W (фиг.2) происходит симметричный изгиб мембраны 4 за счет возникновения инерционной силы, нормальной к поверхности мембраны и равномерно распределенной по площади контура ее закрепления. Поскольку внешний контур мембраны 4 жестко связан с торцами цилиндров 2 и 3, то он лишен возможности поворота при изгибе мембраны, т.е. мембрану 4 можно рассматривать как жестко защемленную по внешнему контуру, а действие инерционной силы - распределенной по этому контуру .In the presence of acceleration W (Fig. 2), a symmetrical bending of the membrane 4 occurs due to the inertial force normal to the surface of the membrane and uniformly distributed over the area of its fastening contour. Since the outer contour of the membrane 4 is rigidly connected with the ends of the cylinders 2 and 3, it is deprived of the possibility of rotation when the membrane is bent, the membrane 4 can be considered as rigidly clamped along the external contour, and the action of the inertial force is distributed along this contour.

Изгиб мембраны приводит к возникновению в цилиндре дополнительных механических напряжений, которые максимальны на границе соединения цилиндра с мембраной и уменьшаются по высоте цилиндра.Bending of the membrane leads to the appearance of additional mechanical stresses in the cylinder, which are maximum at the interface between the cylinder and the membrane and decrease along the height of the cylinder.

В конструкции акселерометра соотношение геометрических параметров мембраны 4 и цилиндров 2, 3, обусловливает значительное превышение тангенциальных напряжений б Τ' (фиг. 2) в пьезоэлементе над нормальными^, что и обеспечивает увеличение чувствительности при измерении ускорений.In the design of the accelerometer, the ratio of the geometric parameters of the membrane 4 and cylinders 2, 3, causes a significant excess of the tangential stresses b б '(Fig. 2) in the piezoelectric element over normal ^, which provides an increase in sensitivity when measuring accelerations.

Для этого толщина мембраны t выбирается из условия t < гдеFor this, the membrane thickness t is selected from the condition t <where

Rtp - средний радиус цилиндра 3, 0^ - толщина стенки цилиндра.Rtp is the average radius of the cylinder 3, 0 ^ is the wall thickness of the cylinder.

Минимальная же толщина мембраны ограничена ее прочностью и резонансной частотой, которая должна быть выше рабочей частоты акселерометра. Уменьшая толщину мембраны, возможно уменьшить инерционную массу акселе-The minimum membrane thickness is limited by its strength and resonant frequency, which should be higher than the operating frequency of the accelerometer. By reducing the thickness of the membrane, it is possible to reduce the inertial mass of the accelerator

Claims

..I ;. , -,, The invention relates to the measurement of motion parameters, in particular, piezoelectric accelerometers, and can be used to measure vibration parameters. Piezoelectric accelerometers with piezoelectric elements mounted between the inertial mass and the housing tl and 2} are known. Known accelerators have relatively low sensitivity and are subject to lateral accelerations. Piezoelectric accelerometers with cantilever sensing elements have relatively low impact strength and are limited to the frequency range of operation. The closest in technical essence and the achieved result is an accelerometer containing a sensing element fixed in a housing by means of a rod, made in the form of an inertial mass placed along the periphery of a flat membrane, a piezoelectric element mounted on a membrane, the central part of which is rigidly fastened to the rod 3. The purpose of the invention is to increase the sensitivity of the accelerometer. To achieve the goal, the inertial mass in the accelerometer is made in the form of two hollow coaxial cylinders with equal wall thickness and located on opposite sides of the membrane, at least one of the cylinders being the nbeaq element, and the membrane thickness t is associated with an average radius piezoelectric element RCP and cylinder wall thickness ff by the ratio t S. FIG. 1 shows a simplified structural diagram of a piezoelectric accelerometer; in fig. 2 - option a. Xelerometer with two piezoelectric elements. The accelerometer contains a base 1, an inertial mass in the form of two cylinders 2 and 3, mounted on opposite sides of the membrane 4 of elastic material and rigidly attached to it by the ends. The membrane j is rigidly centered with the base. Base 1, depending on the method of fixing on the measurement object, can be made either solid (Fig. 1) or in the form of a cylindrical tube (Fig. 2) coaxially mounted with cylinders 2 and 3. Cylinder 2 is made of p.ezoceramics Accelerometer it is equipped with a protective casing 5. The accelerometer works as follows. With the acceleration limb W (Fig. 2), a symmetric bending of the membrane t occurs due to the occurrence of an inertial force, normal to the membrane surface and uniformly distributed over the area of its fixing contour. Since the outer contour of the membrane C is rigidly connected with the ends of cylinders 2 and 3, it is deprived of the possibility of rotation during bending of the membrane, i.e. The membrane k can be considered as rigidly clamped along the external contour, and the action of inertial force - distributed along this contour. The bends of the membrane lead to the appearance of additional mechanical stresses in the cylinder, which are maximal at the interface between the cylinder and the membrane and decrease along the height of the cylinder. In the design of the accelerometer, the ratio of the geometric parameters of the membrane t and cylinders 2, 3, causes a significant excess of tangential stresses C (Fig. 2) in the piezoelement over normal, which provides an increase in sensitivity when measuring accelerations. For this, the membrane thickness t is chosen from the condition t., Where RCP is the average radius of cylinder 3, (f is the wall thickness of the cylinder. The minimum thickness of the membrane is limited by its strength and resonant frequency, which should be higher than the operating frequency of the accelerometer. Decreasing the thickness of the membrane is possible reduce the inertial mass of the accelerometer rotor with an increase in its sensitivity .In Fig. 2, a simplified structural diagram of the accelerometer is presented, in which the inertial mass is made entirely of piezoelectric ceramics and consists of two cylinders, (symmetrically fixed on both sides of the membrane, made, for example, of titanium. In addition to increasing sensitivity in measuring acceleration, the design of the sensing element reduces the weight and dimensions of the proposed accelerometer. The invention Piezoelectric accelerometer, containing a sensing element fixed in the housing by means of a rod , made in the form of inertial mass, placed on the periphery of a flat membrane, a piezoelectric element mounted on a membrane e, the central part of which is rigidly fastened to the rod, which means that, in order to increase the sensitivity of the accelerometer, the inertial mass is made in the form of two hollow coaxial cylinders having equal wall thickness and located from opposite membrane sides, and at least one of the cylinders is a piezoelectric element, and the membrane thickness t is seated with an average raius of the piezoelectric element Rj.p and the thickness of the cylinder wall by the f3Rap ratio. Sources of information taken into account during the examination 1. Geek L. D. Measurement of vibrations. Ovosibirsk, Science, 1972, p. 18990.

2. Instruments and systems for measuring vibration, noise and shock. Prince B. ed. V.V Klyueva. M., Machine building. 1978, p. 51. ..

3.Iorish Yu.I. Vibrometry. State Aukhtekhizdat engineering literature. M., 19bZ, p. 5b9, figure 1. 3 P (prototype).

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