EP0799097B1 - Vorgespannten ring akustischer wandler - Google Patents

Vorgespannten ring akustischer wandler Download PDF

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Publication number
EP0799097B1
EP0799097B1 EP95942751A EP95942751A EP0799097B1 EP 0799097 B1 EP0799097 B1 EP 0799097B1 EP 95942751 A EP95942751 A EP 95942751A EP 95942751 A EP95942751 A EP 95942751A EP 0799097 B1 EP0799097 B1 EP 0799097B1
Authority
EP
European Patent Office
Prior art keywords
sectors
annulus
ring
tightening
keys
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
Application number
EP95942751A
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English (en)
French (fr)
Other versions
EP0799097A1 (de
Inventor
Marc Edouard
Bernard Loubieres
Pascal Bocquillon
Olivier Lacour
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thales SA
Original Assignee
Thomson CSF SA
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Publication date
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Publication of EP0799097A1 publication Critical patent/EP0799097A1/de
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Publication of EP0799097B1 publication Critical patent/EP0799097B1/de
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
    • B06B1/0644—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element
    • B06B1/0655—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element of cylindrical shape

Definitions

  • the present invention relates to transducers piezoelectric in the form of a ring and which are provided with means for prestressing this ring to apply a determined value constraint. It also relates to the processes which allow to implement these means to apply said prestress at the ring.
  • piezoelectric transducers that provide waves acoustic, more particularly low frequency acoustic waves, from an electrical excitation signal.
  • a special form of such transducer is that of a torus with rectangular section, formed of a set of head-to-tail polarized ceramic segments assembled by gluing with interposition of an electrode between each segment. The segments thus excited contract and expand to the rhythm of electrical signals which are applied by the electrodes, and this tangential movement of segments results in a radial extension and contraction of the ring. This movement therefore causes the production of acoustic waves which are emitted with radial symmetry around the axis of the ring in the environment, generally the sea, in which the transducer is immersed.
  • the rings are subjected to high amplitude piezoelectric stresses and this effect is all the more marked as the frequency of the acoustic waves to be emitted is low.
  • the ring would tend to disjoin, first of all at the interfaces between the different segments and then by pure and simple rupture of the piezoelectric ceramics from of a certain emission level.
  • we are led to prestress the ring by compressing it using means which apply radial forces directed towards the center and distributed evenly over the outer surface of the ring.
  • These radial constraints induce tangential stresses which tend to maintain the segments united with each other and oppose the creation of tensile stress ceramics, to which we know that this type of material is particularly fragile.
  • This transducer uses wedge shaped wedges, on the one hand, to connect the different straight segments assembled from stacks of piezoelectric elements to give a curvature to the whole, and on the other hand, to provide electrode surfaces for different stacks.
  • the invention provides a prestressed ring acoustic transducer, of the type comprising a set of piezoelectric segments arranged in the form of a ring, grouped for form substantially identical sectors separated by wedge wedges, characterized in that it includes in in addition to end pieces attached to the ends of these sectors for delimit wedge-shaped intervals between them, the most narrow is directed towards the inside of the ring, shaped clamps of corner adapted to these intervals and placed in them, a ring conformator allowing all sectors to be maintained, and clamping means for sliding the clamps towards inside the ring to prestress the segments by the ring conformator.
  • the transducer comprises in in addition to strain gauges fixed on the interior face of the sectors for to measure the stresses applied to the segments.
  • the clamping means are formed of screws fixed in holes made in the internal face of the wedges clamping and provided with washers coming to rest on the parts end of sectors to allow traction on the holds when screwing the screws.
  • the intervals remaining of a part between the shims and the shaping ring and secondly between these same clamps and the clamping means are plugged with a filling product when the setting is obtained.
  • the dynamic stiffness of the ring conformator is substantially ten times weaker than that of the segments piezoelectric.
  • the invention further provides a method for adjusting such a transducer mainly characterized in that it is tightened gradually tightening means by monitoring the indications given by the strain gauges to obtain on each sector identical and equal constraints to the desired value.
  • the ring piezoelectric forming the transducer is achieved by assembling a set of elementary segments 101 having the form of prisms with trapezoidal section quite similar to those used in the prior art.
  • the ring is divided into a set of substantially identical sectors 102 bringing together subsets of segments.
  • the diameter of the ring is of the order of 20 cm and it is divided into 5 sectors comprising each 8 segments.
  • FIG. 3 It is formed of 8 elementary segments 101 in piezoelectric ceramic, PZT for example. These segments are glued together with interposition electrodes 103 which allow the application of electrical voltages of excitement. According to a known technique, the segments are polarized tangentially alternately in opposite directions. The electrodes 103 are joined alternately to connections 104 and 105 which allow these electrical voltages to be applied to the electrodes.
  • ends of the sector are provided with parts metal bonded to the outer faces of the end segments.
  • These metal parts are wedge-shaped and their outer side faces make an angle ⁇ with the direction of the radius of the ring, as shown in FIG. 1. This angle ⁇ is such that the width of the corner is greater over the inner surface of the ring only on the outer surface thereof.
  • strain gauge 107 there is also arranged on the inner face of the sector at least one strain gauge 107, which makes it possible to measure the constraints applied to the sectors at the level of this interior face.
  • This strain gauge is for example produced in the known form of a film supporting metal electrodes arranged in such a way that the extension or contraction of the surface on which the gauge is stuck causes a variation in resistance of these electrodes according to a law known.
  • All 5 sectors are arranged inside a ring conformator 108 and which makes it possible to define the shape and the dimensions of the piezoelectric ring.
  • This ring is for example made of glass epoxy with a carefully polished interior surface.
  • the dimensions of the sectors are provided so that there remains a clearance between the metal parts of the ends of two adjacent sectors. This clearance is filled by shims having the form of corners 109. These wedges, a copy of which is shown in FIG. 2, therefore come place themselves between the sectors and allow these sectors to be blocked at inside the shaping ring 108.
  • the angle between the two faces lateral of these wedges is studied to correspond to the angle alpha of the end pieces of the sectors, so that when the wedges are in position these outer faces are applied to the faces exterior of these end pieces with such minimal angular play as possible, to avoid undue stress at the contact points between the wedges and the end pieces.
  • the faces of the shims 109 oriented towards the inside of the ring are provided with tapped holes 110, here 3 in number, which can be used to receive clamping devices from screw into these holes by pressing on the faces of the end pieces 106 themselves oriented towards the inside of the ring.
  • These pieces of tightening may be more or less complicated, but in the example of shown embodiment they are composed of screws 111 on which are threaded washers 112. These screws are screwed into the holes threaded, then on the washers, themselves supported on the parts 106. There is thus exerted on the wedges 109 an inward traction of the ring which tends, given the angles ⁇ , to spread the sectors 101 and to enlarge the ring formed by all of these sectors and wedges. Under this widening effect the piezoelectric ring presses firmly on the inside of the shaping ring 108, which, in a first, keep all parts in position.
  • the invention proposes to use the strain gauges 107 described above. For this, they will be connected to measuring means 113 which allow to determine the stress at these gauges.
  • the constraint where these gauges are placed indicates, at a coefficient near known multiplier, the global stress applied to ceramics forming each sector. The sectors are small enough that the stresses thus obtained and measured are uniformly distributed. In the case of a larger ring, we would eventually have to use a more sectors.
  • the tightening of the screws will be done gradually by constantly checking the evolution of the constraints, so as to obtain the desired overall stress and to minimize maximum deviations between the stresses measured locally.
  • the shaping ring 108 is of course involved in the acoustic characteristics of the transducer thus produced, as is moreover the case in the other prestressing systems already known. We have determined that to get correct results, especially don't not excessively disturbing the functioning of the ring piezoelectric, it was better to use a shaping ring whose dynamic stiffness is about ten times lower than that of the ring piezoelectric ceramic.
  • this device is particularly easy to implement and therefore inexpensive.
  • it is modular, which makes it possible, if necessary, to replace only one segment in case of damage to it. Constraints are distributed in a remarkably uniform manner, and their variations over the time is very low. We can completely adjust this preload, either by depending on operational conditions, either to correct the drift in the time.
  • the assembly is removable, which allows the repairs cited above.
  • the metal parts 106 and 109 if necessary, promote thermal drainage, especially when the ring is requested by very high electrical powers.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Measuring Fluid Pressure (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)
  • Transducers For Ultrasonic Waves (AREA)

Claims (6)

  1. Vorgespannter Ring-Schallwandler des Typs, der eine Gruppe von piezoelektrischen Segmenten (101) enthält, die in Ringform angeordnet und so gruppiert sind, daß sie im wesentlichen gleiche Sektoren (102) bilden, die durch keilförmige Klötze (109) getrennt sind, dadurch gekennzeichnet, daß er außerdem Endstücke (106), die an den Enden dieser Sektoren befestigt sind und zwischen sich keilförmige Zwischenräume begrenzen, wovon das schmale Ende zum Innenraum des Rings gerichtet ist, keilförmige Klemmklötze (109), die an diese Zwischenräume angepaßt und in ihnen angeordnet sind, einen Spannring (108), mit dem die Gesamtheit der Sektoren gehalten werden kann, sowie Klemmittel (110-112) enthält, die ermöglichen, die Klemmklötze in den Innenraum des Rings gleiten zu lassen, um die Segmente durch den Spannring vorzuspannen.
  2. Wandler nach Anspruch 1, dadurch gekennzeichnet, daß er außerdem Dehnungsmeßstreifen (107) enthält, die an der Innenfläche der Sektoren befestigt sind, um die Messung der an die Segmente angelegten tangentialen Beanspruchungen zu ermöglichen.
  3. Wandler nach irgendeinem der Ansprüche 1 und 2, dadurch gekennzeichnet, daß die Klemmittel aus Schrauben (111) gebildet sind, die in Löchern befestigt sind, die in der Innenfläche der Klemmklötze (109) ausgebildet sind, und mit Unterlegscheiben (112) versehen sind, die sich an den Endstücken (106) der Sektoren abstützen, um die Ausübung eines Zugs auf die Klötze zu ermöglichen, wenn die Schrauben eingeschraubt werden.
  4. Wandler nach irgendeinem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die Zwischenräume, die einerseits zwischen den Klemmklötzen (109) und dem Spannring (108) und andererseits zwischen diesen Klemmklötzen und den Klemmitteln (110-112) vorhanden sind, mit einem Füllstoff verstopft werden, wenn die Einstellung erhalten worden ist.
  5. Wandler nach irgendeinem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die dynamische Steifheit des Spannrings (208) im wesentlichen zehnmal geringer als diejenige der piezoelektrischen Segmente (101) ist.
  6. Verfahren zum Einstellen eines Wandlers nach irgendeinem der Ansprüche 2 bis 5, dadurch gekennzeichnet, daß die Klemmmittel (110-112) progressiv geklemmt werden, wobei die Angaben überwacht werden, die von den Dehnungsmeßstreifen (107) ausgegeben werden, um in jedem Sektor völlig gleiche Beanspruchungen, die gleich dem gewünschten Wert sind, zu erhalten.
EP95942751A 1994-12-23 1995-12-15 Vorgespannten ring akustischer wandler Expired - Lifetime EP0799097B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9415587 1994-12-23
FR9415587A FR2728755B1 (fr) 1994-12-23 1994-12-23 Transducteur acoustique en anneau precontraint
PCT/FR1995/001676 WO1996020046A1 (fr) 1994-12-23 1995-12-15 Transducteur acoustique en anneau precontraint

Publications (2)

Publication Number Publication Date
EP0799097A1 EP0799097A1 (de) 1997-10-08
EP0799097B1 true EP0799097B1 (de) 1998-09-23

Family

ID=9470196

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95942751A Expired - Lifetime EP0799097B1 (de) 1994-12-23 1995-12-15 Vorgespannten ring akustischer wandler

Country Status (7)

Country Link
US (1) US6065349A (de)
EP (1) EP0799097B1 (de)
JP (1) JP3653733B2 (de)
AU (1) AU695815B2 (de)
DE (1) DE69505014T2 (de)
FR (1) FR2728755B1 (de)
WO (1) WO1996020046A1 (de)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2776161B1 (fr) * 1998-03-10 2000-05-26 Thomson Marconi Sonar Sas Antenne d'emission acoustique annulaire demontable
FR2826828B1 (fr) 2001-06-29 2003-12-12 Thomson Marconi Sonar Sas Transducteur acoustique a anneau precontraint
JP2006515427A (ja) * 2003-01-17 2006-05-25 キストラー ホールディング アクチエンゲゼルシャフト センサ用のプレストレス要素
US8854923B1 (en) * 2011-09-23 2014-10-07 The United States Of America As Represented By The Secretary Of The Navy Variable resonance acoustic transducer
FR3015785B1 (fr) * 2013-12-20 2015-12-25 Thales Sa Antenne omnidirectionnelle compacte pour sonar trempe
CN109633614B (zh) * 2018-11-29 2023-08-01 哈尔滨工程大学 一种低后辐射高频换能器线阵

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3043967A (en) * 1960-01-13 1962-07-10 Walter L Clearwaters Electrostrictive transducer
US3230505A (en) * 1963-06-27 1966-01-18 David E Parker Reinforced ceramic cylindrical transducers
US4313510A (en) * 1980-11-24 1982-02-02 General Electric Company Weighing scale with dynamic zero error correction
US4546459A (en) * 1982-12-02 1985-10-08 Magnavox Government And Industrial Electronics Company Method and apparatus for a phased array transducer
DE3542741A1 (de) * 1985-12-03 1987-06-04 Taga Electric Co Ltd Torsionsschwingungseinrichtung
GB9409133D0 (en) * 1994-05-09 1994-11-30 Secr Defence Sonar ring transducer

Also Published As

Publication number Publication date
EP0799097A1 (de) 1997-10-08
FR2728755A1 (fr) 1996-06-28
AU4393496A (en) 1996-07-19
JP3653733B2 (ja) 2005-06-02
US6065349A (en) 2000-05-23
WO1996020046A1 (fr) 1996-07-04
DE69505014D1 (de) 1998-10-29
FR2728755B1 (fr) 1997-01-24
DE69505014T2 (de) 1999-05-06
AU695815B2 (en) 1998-08-20
JPH10511523A (ja) 1998-11-04

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