Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
  • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
  • G01F1/662—Constructional details
• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K9/00—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers
  • G10K9/12—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated
  • G10K9/122—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated using piezoelectric driving means
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
  • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
  • G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
  • G01F23/296—Acoustic waves
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
  • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
  • G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
  • G01F23/296—Acoustic waves
  • G01F23/2968—Transducers specially adapted for acoustic level indicators
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
  • G01N29/22—Details, e.g. general constructional or apparatus details
  • G01N29/24—Probes
  • G01N29/2437—Piezoelectric probes
• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K9/00—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers
  • G10K9/12—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated
  • G10K9/13—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated using electromagnetic driving means
• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K9/00—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers
  • G10K9/18—Details, e.g. bulbs, pumps, pistons, switches or casings
  • G10K9/22—Mountings; Casings
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49002—Electrical device making
  • Y10T29/49005—Acoustic transducer

Definitions

• Ultrasonic transducers in various applications are known from the prior art.
• ultrasonic transducers are used in automotive technology in ultrasonic flow meters, for example in the exhaust system and / or in the intake system of internal combustion engines. Examples of such ultrasonic transducers are described in DE 10 2007 037 088 A1 or the subsequently published German patent application with the number DE 10 2008 055 126.0 from the applicant's own house.
• ultrasonic flowmeters are based on two ultrasonic transducers, which are arranged offset in a flow tube in the flow direction and send each other ultrasonic signals. In this case, measuring arrangements can be used in which at least one reflector is provided, for example in the form of plug-in sensors. Further applications of ultrasonic transducers are, for example, level indicators or distance meters, for example in so-called Parkpilot systems.
• Ultrasonic transducers have in many cases an electrically-acoustic transducer element in the form of a piezoceramic.
• impedance matching that is, in particular a reduction of reflection losses at the interface between ultrasound transducers and the fluid medium in which the ultrasound transducer is to be used
• so-called matching bodies are used, which provide at least partial impedance compensation between the ultrasound transducer Piezoceramic and the impedance of the fluid medium.
• ultrasonic transducers based on a piezoceramic are known in conjunction with so-called ⁇ / 4 impedance matching layers. Examples of such matching body, which also in the context of the present invention can be used, are described in DE 10 2007 037 088 A1 or in DE 10 2008 055 126.0.
• ultrasound transducers having a housing in the form of a one-piece sleeve and an annular rear-side cover are known from the prior art.
• Such ultrasonic transducers are used for example in Parkpilot systems.
• the piezoceramic is usually first electrically contacted by, for example, wires are welded to the piezoceramic and associated with the cover ring contact pins. Subsequently, the piezoceramic is then held with a suction gripper through the cover ring and usually introduced together with the cover ring and the connecting wires in the sleeve.
• the leads receive the bend history desired within the later ultrasonic transducer for optimum durability.
• transducer sleeves usually have to be made very deep, as an interior of the transducer sleeves must be filled with a certain amount of damping material. Furthermore, this depth of the transducer sleeve is usually required lent to allow attachment of contact pins or a UmWallet ist to ensure a corresponding guide length for a precisely aligned installation, for example in a plug-in housing, or to facilitate the general handling of the overall converter , However, this depth of the transducer sleeve, the handling is usually difficult during the building process, since the piezoelectric element must be sunk deep into the transducer sleeve.
• an ultrasonic transducer for use in a fluid medium and a method for producing an ultrasonic transducer for use in a fluid medium are proposed, which at least partially avoid the disadvantages of known ultrasonic transducers and production methods.
• the ultrasound transducer can in particular be produced by a method according to the invention, and the method can be used in particular for producing an ultrasound transducer according to the invention. Accordingly, reference may be made to the description of the ultrasonic transducer for possible embodiments of the method and vice versa.
• the present ultrasonic transducer comprises at least one transducer core with at least one electrical-acoustic transducer element.
• an electric-acoustic transducer element is a basically arbitrary element to understand, which can convert electrical signals into acoustic signals and vice versa. In particular, it may be a monolithic element.
• the electrical-acoustic transducer element comprises a piezoelectric transducer element or is designed as a piezoelectric transducer element.
• the terms “piezo,””piezoceramic,” and “piezoelectric transducer element” are also used as synonyms for the term “electroacoustic transducer element” in the context of the present invention, without limitation of other possible embodiments of the electro-acoustic transducer element.
• the converter core may further comprise further elements, as will be explained in more detail below.
• the converter core may comprise at least one matching body on a side facing the fluid medium, for example according to the above-described prior art. This matching body is arranged to enhance an acoustic coupling between the electro-acoustic transducer element and the fluid medium, such as air or a liquid.
• the matching body provides a material whose impedance is at the geometric mean of the impedances of the electro-acoustic transducer element and the fluid medium.
• a matching body with another, usually higher acoustic impedances.
• the matching body may also comprise a plurality of materials having different acoustic impedances and / or a material having an acoustic impedance gradient.
• the transducer core can have, for example, a radiating surface which assigns the fluid medium and via which ultrasound signals can be emitted to the fluid medium and / or ultrasound signals can be picked up from the fluid medium.
• the radiating surface can be arranged, for example, in an opening of a housing, which will be explained in more detail below.
• this opening may be surrounded by an edge of the housing, for example annular.
• Other geometries are conceivable.
• the radiating surface can be flush with the edge of the housing or arranged in another plane, for example, easily offset into the interior of the housing or slightly offset from the edge towards the fluid medium.
• the ultrasonic transducer comprises at least one housing.
• This housing may be designed in particular sleeve-shaped.
• a housing is understood to mean an element which essentially closes off the ultrasound transducer to the outside and gives the ultrasound transducer its essential shape to the outside.
• the housing can be produced in particular from a metallic material and / or a plastic material and can protect the ultrasonic transducer from external mechanical and / or chemical influences and / or from temperature and / or pressure influences.
• the housing has at least two housing parts. These housing parts are preferably configured completely separated and accordingly can preferably be manufactured and / or handled completely independently of one another.
• At least a first housing part is provided, which surrounds the transducer core at least partially.
• the housing part a Enclosure body of the converter core and / or the electrical-acoustic transducer element completely or partially enclose.
• the first housing part for example, be designed annular or tubular, for example with a round or polygonal cross-section. An inner diameter of this housing part can fit the outer diameter of the
• the first housing part surrounds the transducer core in such a way that a rear side of the electrically-acoustic transducer element facing away from the fluid medium is accessible.
• the term "accessible” is understood to mean an arrangement in which the first housing part has at least one opening on the rear side, for example an opening with a higher opening width than the transducer core, through which the rear side of the electrically-acoustic Transducer element can be accessed, for example, for contacting the electrically acoustic transducer element.
• the opening and / or the converter core can be configured such that the converter core can be introduced into the first housing part through the opening in the first housing part and / or removed from it.
• this rear side of the electrical-acoustic transducer element can terminate flush with the rear side of the first housing part or even protrude beyond this first housing part, so that it is accessible, for example, for electrical contacting.
• the first housing part can also easily project on the rear side, so that the rear side of the electro-acoustic converter element is slightly offset from the rear side of the first housing part inside the housing, but still the rear side of the electrical-acoustic transducer element for an electric Contacting should be accessible.
• At least one second housing part is provided, which is connected to the first housing part, for example via a cohesive and / or non-positive and / or positive connection.
• This second housing part is configured and arranged in such a way that it substantially closes off the ultrasound transducer on its side facing away from the fluid medium.
• a conclusion in this regard means no hermetic conclusion, but a definition of the outer shape of the ultrasonic transducer on the side facing away from the fluid medium and / or a mechanical stabilization of accommodated in the housing components of the ultrasonic transducer.
• substantially in this connection can be understood to mean a termination in which at least slight openings, for example for passages or as a compensation opening with regard to thermal expansion of parts of the transducer (eg a damping element), can be tolerated
• the transducer interior for example, the electrical-acoustic transducer element and / or the entire transducer core and / or a decoupling element and / or a damping element by the second housing part in Are held inside the housing so that these components can not be removed from the housing.
• the second housing part can provide a rear support, on which one or more of the elements transducer core, electrically acoustic transducer element, decoupling element, damping element, damping and / or decoupling material or other elements, which are arranged in the interior of the housing supported could be.
• the second housing part may comprise on its side facing away from the fluid medium at least one support element, for example an inwardly projecting collar, on which one or more of said elements of
• a pressure of the fluid medium can be accommodated.
• at least one rear opening is provided in the second housing part, then this should not be too small, because then the supporting effect is getting better, but thermally induced expansions of the converter interior, such as a Dämpfungsvergusses, then load the optional sealing film all the more would.
• coefficient of thermal expansion and filling volume may be in the Practice a compromise for the optimal opening size of the second housing part can be found.
• the first housing part may surround the transducer core in particular annular.
• the first housing part for example, wholly or partially be configured as a ring and / or as an annular sleeve.
• the first housing part may have an end face, in particular a circular end face which assigns the fluid medium.
• a radiating surface of the transducer core that is to say a surface via which acoustic signals are emitted from the transducer core to the fluid medium and / or via which acoustic signals are received from the fluid medium by the transducer core, can be annularly surrounded by this end face.
• the radiating surface can be arranged in a plane with this end face of the first housing part.
• At least one sealing film is provided which shields and / or seals a housing interior of the ultrasonic transducer against influences from the fluid medium, for example chemical influences and / or pressure influences.
• a sealing film may for example be glued or otherwise connected to the end face of the first housing part and / or to the emission surface.
• the electrically-acoustic converter element can terminate flush with the first housing part, in particular on the side facing away from the fluid medium, or protrude beyond the first housing part. This embodiment is particularly favorable to a simple electrical contacting of the electric-acoustic
• the second housing part may in particular be configured cup-shaped.
• the second housing part may, for example, be slipped over the first housing part from the side facing away from the fluid medium.
• the first housing part and the second housing part may, for example, be connected to one another by a cohesive connection method, in particular a welding method.
• a cohesive connection method in particular a welding method.
• ultrasonic welding in particular offers itself here.
• other connection techniques can also be used, for example non-positive and / or positive locking and / or cohesive bonding techniques, for example by laser welding, gluing or by clipping the second housing part to the first housing part or vice versa.
• the ultrasonic transducer may further comprise at least one contact clip for electrically contacting the electrical-acoustic transducer element.
• the contact clip may comprise, for example, one, two or more electrical contacts for contacting electrodes of the electro-acoustic transducer element.
• the at least one contact clip can, for example, be substantially dimensionally stable, that is to say that it is at least under
• the contact clip may in particular be made of a metallic material.
• the contact clip can protrude through the second housing part into an interior of the ultrasonic transducer and be electrically connected there to the electrically-acoustic transducer element.
• This electrical connection between the contact clip and the electrically-acoustic transducer element can be effected, for example, by a direct contacting of the electrically-acoustic transducer element by the contact clip.
• other joining techniques can also be used, for example wire bonding techniques.
• the contact clip may in particular be connected to the first housing part. In this way, the contact clip can be fixed in particular spatially.
• This connection may for example comprise a positive and / or non-positive connection.
• the contact clip may comprise one or more connecting elements, for example clips, by means of which a plugging and / or clipping of the contact clip on the first housing part is possible.
• the contact clip can fulfill additional tasks in addition to an electrical contacting of the electrical-acoustic transducer element.
• it can be configured at least partially as electromagnetic shielding.
• the contact clip for example, at least partially enclose the electrical-acoustic transducer element.
• the transducer core in the at least one electroacoustic transducer element may comprise further elements.
• the converter core may comprise at least one matching body, for example according to the above-described prior art. This can be designed to improve an acoustic coupling between the electrical-acoustic transducer element and the fluid medium.
• the first housing part at least partially surround the matching body, for example, enclose annular.
• the first housing part and the second housing part may, as shown above, be wholly or partly made of a metallic material and / or a plastic material and / or other materials. Particular preference is given to materials which at the same time have good internal damping and the possibility of producing even filigree structures.
• liquid crystal polymers LCP can be used.
• plastics can also be used, for example PPA (polyphthalamide), PBT (polybutylene terephthalate) and / or PEEK (polyether ether ketone) and / or other plastics.
• PPA polyphthalamide
• PBT polybutylene terephthalate
• PEEK polyether ether ketone
• plastic materials may be unfilled or filled, for example with a glass fiber filling, ceramic, carbon or the like.
• the first housing part may, in particular, have an opening facing the fluid medium.
• the first housing part as shown above, have an end face, for example, an annular end face which surrounds the opening.
• the radiating surface of the transducer core may be disposed within this opening.
• the opening may be closed by at least one sealing film.
• the sealing film can be connected, for example, to the first housing part, for example the end face.
• At least one housing interior can be provided within the ultrasonic transducer.
• This housing interior can for example be at least partially limited by the second housing part.
• This interior of the housing may in particular be at least partially filled with a filling and / or damping material, for example a damping casting.
• silicones are suitable for this purpose.
• the damping material can be used directly with the converter core, for example the electrical acoustic transducer element, are in communication and can be configured to provide as rapid as possible attenuation after excitation of the transducer core.
• the filling and / or damping material can furthermore be designed to discharge pressure forces exerted on the transducer by the fluid medium via the converter core and the filling and / or damping material on the rear side onto the second housing part.
• a method for producing an ultrasonic transducer for use in a fluid medium is also proposed.
• the method can be used in particular for producing an ultrasonic transducer in one or more of the embodiments described above, but in principle also other types of ultrasonic transducers can be produced with the proposed method.
• the method comprises the steps described below, which need not necessarily be performed in the order shown. Individual process steps can also be performed simultaneously and / or temporally overlapping. Furthermore, individual or several process steps can be carried out repeatedly.
• a transducer core is produced, which comprises at least one electrical-acoustic transducer element.
• At least one first housing part is provided, such that the first housing part at least partially encloses the transducer core.
• the converter core can already be completely configured, however, it can also only be partially configured, for example by providing at this time only one matching body of the converter core, which is at least partially enclosed by the first housing part.
• the first housing part is configured in this way and is provided in such a way that a rear side of the electrically-acoustical transducer element facing away from the fluid medium is accessible, for example for an electrical contacting operation.
• at least one second housing part is provided.
• This second housing part is connected to the first housing part, such that the ultrasound transducer is essentially completed on its side remote from the fluid medium by the second housing part.
• the manufacturing method can be particularly easily designed such that at least one sealing film, for example of the type described above, is used.
• it can be a plastic film, for example, as will be explained in more detail below, a polyimide film or another film material.
• metallic films are also possible in principle.
• the method can be configured such that the first housing part and the converter core or a part of the converter core, for example a matching body, are applied to the sealing film.
• these can be connected to the sealing film, for example by an adhesive method and / or another type of cohesive method.
• a gap between the transducer core or the part of the transducer core and the first housing part is at least partially filled by at least one damping and / or decoupling material.
• this damping and / or decoupling material may comprise a plastic material, in particular a liquid silicone rubber (liquid silicone
• the filling can be done in particular by a Vergussvorgang.
• first housing part and the second housing part Before connecting the first housing part and the second housing part can in particular a contact clip for contacting the electrical-acoustic
• Transducer element are connected to the first housing part.
• this connection may in particular include a positive and / or non-positive connection.
• the contact clip may in particular have a plurality of contiguous electrical contacts, wherein the electrical contacts after connection of the contact clip with the first
• Housing part for example, after applying the second housing part to the first housing part, can be separated from each other.
• the proposed ultrasonic transducer and the proposed method have numerous advantages over known ultrasonic transducers and known production methods.
• a basis for a cost-effective and mass-produced ultrasonic transducer such as an air ultrasonic transducer, laid, as it can be used for example for gas flow measurement in the automotive sector.
• An ultrasonic transducer can be used, for example, as an ultrasonic flow meter, ie as an ultrasonic flow meter, on the pressure side of supercharged internal combustion engines.
• the ultrasonic transducer can be simple and inexpensive.
• the ultrasonic transducer can be manufactured on the basis of a piezoceramic, optionally with an impedance matching layer, with a housing in the form of, for example, a two-part sleeve.
• the first housing part may be configured as a front-side part of the sleeve and connected to the matching layer. This connection can take place, for example, via at least one decoupling element and / or at least one sealing foil and / or a coating and / or a combination of these elements.
• the first housing part for example the front-side part of the entire sleeve, can be made so flat that the back side of the piezo lies approximately in a plane with the rear edge of the sleeve.
• the piezo can be easily accessible during the assembly, bonding and contacting process.
• the second housing part may be configured in particular as a rear sleeve part. This second housing part can be configured as a deeper sleeve part than the first housing part. As described above, the second housing part can accordingly accommodate a damping and / or a decoupling and / or a supporting material, for example a potting material.
• the housing Due to the at least two-part design of the housing, for example by the configuration of the two-part sleeve, preferably with a relatively flat front part, a good accessibility of the piezor back side is ensured. This makes it possible to realize an advantageous manufacturing sequence.
• the invention allows a total of more degrees of freedom of the design, for example with respect to the choice of the contacting technique. As a result, special requirements for the ultrasonic transducer can ultimately be met, for example requirements of the automotive sector, in particular engine mounting conditions.
• Figure 1 is a sectional view of an embodiment of an ultrasonic transducer according to the invention.
• Figure 2 is a sectional view of the embodiment in Figure 1 with a sectional plane perpendicular to the sectional plane in Figure 1;
• Figure 3 shows an embodiment of a contact clip.
• FIG. 1 a possible embodiment of an ultrasonic transducer 1 10 according to the invention is shown.
• Figure 1 shows a sectional view of the side
• Figure 2 shows a sectional view perpendicular to the sectional plane in Figure 1, viewed from above.
• the ultrasonic transducer 1 10 comprises as a transducer core 1 12, which in turn comprises an electric-acoustic transducer element 1 14 and a matching body 1 16.
• the matching body 1 16 may be configured, for example, as a ⁇ / 4 impedance matching layer.
• the electrical-acoustic transducer element 1 14 can beispielswei se configured as a piezo element and be connected directly or at least one inter mediate layer (for example, an intermediate layer to compensate thermomechanical tensions) with the matching body 1 16.
• the matching body 1 16 has a slightly higher ren diameter di than the electrically-acoustic transducer element 1 14.
• the entire transducer core 1 12 therefore have a total diameter di, for example, a diameter of 8 mm.
• the converter core 1 12 is introduced into a housing 1 18, which is designed in two parts in the illustrated embodiment. Also more than two parts can be provided in principle. Accordingly, the housing 1 18 comprises a front housing part 122 facing the front, in use a fluid medium 120 (see FIG. 1), and a rear second housing part 124 facing away from the fluid medium 120.
• the first housing part 122 which is also referred to below as the first housing sleeve or Front sleeve is called, for example, be configured as a substantially cylindrically symmetric sleeve.
• the first housing part 122 is configured as angled in an exemplary manner and has an axial part 128 extending parallel to an axis 126 and a radial part 130 extending substantially perpendicular to the axis 126.
• the radial part 130 has an end face 132 which assigns the fluid medium 120.
• This end face 132 is designed, for example, annular. It has an inner diameter d 2 of, for example, 12 mm.
• an intermediate space 134 may be formed between the converter core 12 and the first housing part 122 at least partially surrounding it.
• this intermediate part 134 may be substantially cylindrical-sleeve-shaped, with a thickness of, for example, 1 mm.
• the gap 134 as in the embodiment in Figures 1 and 2, for example, be wholly or partially filled with a decoupling element 136, which indeed provides a good mechanical fixation of the transducer core 1 12 in the housing 1 18, but a structure-borne sound transmission between the housing. 1 18 and converter core 1 12 at least dampens.
• a decoupling element 136 As the material for the decoupling element 136, a potting material may be used, for example a liquid silicone rubber (LSR).
• LSR liquid silicone rubber
• the converter core 1 12 has an emitting surface 138 on its side facing the fluid medium 120. This is arranged in the illustrated embodiment in a plane with the end face 132 of the first housing part 122. Also, the side of the decoupling element 136 facing the fluid medium 120 preferably does not protrude beyond this common plane
• the ultrasonic transducer 110 may be sealed by at least one sealing element 140, for example a sealing film 142.
• sealing elements 140 may also be considered, for example coatings.
• the sealing foil may, for example, cover the large area with the emitting surface 138 and / or the
• End face 132 may be connected, for example by gluing.
• the first housing part 122 On the rear side, ie on the side facing away from the fluid medium 120, the first housing part 122 is designed comparatively short, so that in the illustrated embodiment, the back of the transducer core 1 12 is flush with the rear of the first housing part 122 or even protrudes beyond this. Accordingly, the electrically-acoustic transducer element 1 14 is preferably accessible freely from the rear side.
• the electrical-acoustic transducer element 1 14 is contacted via a contact clip 144.
• This contact clip 144 is, for example, in a radial extension 146 of the second housing part 124, which is otherwise configured, for example, substantially cylindrical, for example cup-shaped, out.
• the contact clip 144 is guided at its upper end through an opening 150 in the second housing part 124 to the outside and has at its lower end preferably connecting elements 148 for connecting to the first housing part 122.
• These connecting elements 148 are configured in the darg Anthonyen embodiment, as can be seen for example in Figure 1, clip-shaped or hook-shaped and can be slipped over the rear end of the axial part 128 of the first housing part 122 and / or clamped. In this way, an example positive and / or non-positive connection can be achieved.
• the contact clip 144 is shown by way of example in FIG. Thereafter, it can be seen that the contact clip 144 in the illustrated embodiment has two electrical contacts 152, 154, which may be connected to one another at their upper end by a web 156, for example.
• This web 156 after assembly of the ultrasonic transducer 1 10, as will be explained in more detail below, are removed.
• the connecting elements 148 may protrude laterally beyond the substantially axially extending electrical contacts 152, 154, for example by 2.2 mm.
• the electrical contacts 152, 154 may, for example, have a width of 2.2 mm and may, for example, be spaced at a distance of 1.4 mm. As can be seen, for example, from FIG.
• the electrical contacts 152, 154 can provide contact surfaces 158.
• a contact 160 can be guided to corresponding contacts of the electrically-acoustic transducer element 14, for example by wire bonding. Because the back of the converter kerns 1 12 is relatively freely accessible even when placed in the first housing part 122 transducer core 1 12 before applying the second housing part 124, such contacting by applying, for example, wires or other bonding techniques or clamping techniques or other contacting techniques is easily possible.
• the cup-shaped second housing part 124 is applied to the first housing part 122 and connected thereto, for example by ultrasonic welding.
• the connection is designated by the reference numeral 162 in FIG. This forms on the fluid medium
• This interior 164 may be configured, for example, a large area, so that it can be filled, for example, completely or partially with at least one filling and / or damping material 166, for example, a damping Verguss.
• the first housing part 122 for example, comprise one or more openings 168, which can be subsequently closed or which may also remain in the housing 1 18.
• the ultrasonic transducer 1 10 is therefore designed with a two-part housing 1 18, for example a two-part sleeve.
• a transducer front points downward in FIG. 1, toward the fluid medium 120.
• a corresponding front-side sleeve part can be designed, for example, annular.
• the end face 132 of the first housing part 122 can be glued onto the sealing foil 142.
• the matching body 1 16 can be adhered to this sealing film 142, so that these elements are fixed.
• the sealing film 142 for example, polyimide film (for example, Kapton) can be used.
• the decoupling element 136 can then be cut in and / or cast as acoustic decoupling, for example an LSR.
• the electrically-acoustic transducer element 1 14 can be glued, and the connecting elements 148, such as the contact pins of the contact clip 144 can be snapped onto the axial part 128.
• the connecting elements 148 such as the contact pins of the contact clip 144 can be snapped onto the axial part 128.
• a contiguous contact stirrup 144 can be used.
• individual contact pins can also be used.
• the contact clip 144 can, for example, way to be opened after installation of the ultrasonic transducer 1 10. Subsequently, the application of the contact 160 can take place.
• copper wires or ribbons can be thermocompression-welded on the piezoelectric electrodes and / or the contact surfaces 158, for example, the Whylands the contact pins, such as the contact clip 144, are attached.
• the contact clip 144 may be attached directly to the piezoelectric electrodes and / or contacting surfaces 158, for example by welding.
• the rear sleeve part can be placed in the form of the second housing part 124 and connected to the first housing part 122, for example the sleeve ring, in particular by ultrasonic welding.
• a damping potting and / or other filling or damping material 166 can be filled and cured.
• the rear opening 168 can not only serve to fill the filling or damping material 166, but can also make it possible to compensate for thermal expansions of the damping encapsulation within the sensor operating area.
• this opening 168 should only be dimensioned so large that the transducer interior, so the interior 164, at back pressure of the fluid medium to be measured 122, for example, air, still sufficiently supported on the sleeve to the rear.
• the size of the opening 168 and / or its geometric configuration can be designed for this purpose depending on the filling volume or the filling geometry and the hardness and the expansion coefficients of the materials involved so that the radiating surface facing the fluid medium both under pressure load and moved as little as possible under thermal stress.
• the ultrasonic transducer 1 10 shown in Figures 1 and 2 represents only one of several embodiments.
• the embodiment may, as well as other embodiments of the present invention, advantageously further developed and / or modified in various ways.
• an internal decoupling can be provided which offers a well-defined, hard and easily sealable mechanical interface to the outside.
• the material of the housing 1 18 may preferably be made of plastic, since plastic has a particularly good decoupling property. Structure-borne sound components, which are transmitted, for example, via the damping material 166, the decoupling element 136 or the sealing film 142, are sufficiently damped due to the sound damping of the plastic.
• LCP liquid crystal polymer
• Other materials include PPA, PBT, PEEK or other plastics.
• the plastic materials can be filled or unfilled, for example with a filling made of glass fibers, ceramics, carbon or the like.
• metal and / or a composite material can be selected as the material for the housing 1 18 and / or the housing parts 122, 124.
• metal as a sleeve material and / or inserted in plastic metal parts allow EMC shielding.
• metal tends to have long-lasting natural oscillations that could affect the decoupling properties.
• the contact clip 144 can also be divided, for example, into three instead of only two segments or electrical contacts 152, of which two segments are used for piezocontacting, for example, and the third segment is an annular contact. or part-ring-shaped shielding of the electric-acoustic transducer element 1 14 and / or other parts of the ultrasonic transducer 1 10 may represent.
• the material for the sealing film 142 for example
• Polyimide for example, Kapton
• Other, alternatively or additionally usable materials are, for example, fluorinated hydrocarbons, such as Teflon and / or PEEK, other types of thermoplastics or thermosets or coatings that are not applied as a film, for example Parylene, paints or similar materials.
• the film edge of the sealing film 142 can also be sealed separately. This can for example be done simultaneously with the bonding of the ultrasonic transducer 1 10 in a higher-level sensor housing, which is not shown in the figures. In such a higher-order sensor housing, it is also possible, for example, to arrange a plurality of such ultrasonic transducers 16, as is illustrated, for example, in the prior art cited above and / or in DE 10 2004 061404 A1. The ones described there Sensor arrangements may also be realized using an ultrasonic transducer 110 according to the present invention.
• the sealing film 142 can be glued in a separate process step on the sleeve ring of the first housing part 122 and on the fitting body 1 16.
• a connection between the sealing foil 142 and the first housing part 122 and / or the matching body 1 16 can be made in another way, for example in one step with the introduction of the decoupling element 136, for example in an injection mold, for example an LSR -Tool.
• the connection can also be made timely to the LSR process and / or another injection molding process for introducing the decoupling element 136, for example, by the same pressure that also closes or seals the tool, for example the LSR tool.
• decoupling elements 136 may also be used.
• the decoupling element 136 can also be wholly or partially configured and / or mounted as a molded part.
• An advantage of this procedure could be a lower load on the matching layer material.
• a disadvantage of this, however, is a fundamental due to the softer consistency higher tolerance.
• a further variant, which can be used alternatively or additionally, is a gating of the material of the decoupling element 136, for example of the LSR, only to the first housing part 122 and optionally the sealing foil 142, while the matching body 1 16 applied in a separate process step, for example glued , becomes.
• a damping and / or decoupling material can also be introduced by means of a casting technique.
• silicone other materials can be used.
• the decoupling element 136 may also be omitted as a separate substance and / or may be wholly or partly with the
• Damping material 166 are summarized. For example, a single Vergussstoff can be used, which represents a compromise between damping and decoupling.
• This can be, for example, a silicone material.
• flexibilized epoxides with further fillers are also conceivable as the base material.
• Further modifications and / or developments relate to the matching body 1 16. For example, this can be configured according to the prior art described above.
• the matching body 1 16 may consist of glass hollow sphere-filled epoxy and / or of porous sintered polyimide, for example polyimide of the type DuPont Vespel or other materials and / or gradient materials whose acoustic impedance or their impedance curve is selected such that a favorable coupling between the electric-acoustic transducer element 1 14 and fluid medium 120 is given.
• One or more additional layers can be placed between the electrically-acoustic transducer element 1 14 and the matching body 1 16, which protect the electrically-acoustic transducer element 1 14, for example the piezo, against tension, for example by having an expansion coefficient close to the piezo material (the is for example of the order of 10 ppm / K or less) and have a sufficient thickness.
• This at least one layer can simultaneously serve open
• This at least one optional additional layer can, for example, be glued or applied by a molding process and / or be part of the matching body 16, for example the matching layer, in particular with different thermal / acoustic properties.
• the diameter of the electrical-acoustic transducer element 1 14 can be selected so that essentially the piano resonance is utilized for ultrasound generation and / or ultrasound detection.
• the thickness of the electric-acoustic transducer element 14 can be a compromise. The thinner, for example, the piezo is selected, the more flexible he becomes, which makes him more stable with respect to thermal shocks. On the other hand, a too thin piezo too strong flexural vibrations, which can lead to an excessive temperature response of the ultrasonic transducer 1 10 together with the matching body 1 16.
• connection between the electrical-acoustic transducer element 1 14 and the matching body 1 16 or a compensating layer can also be performed without a separate adhesive, for example by a piezoelectric element is embedded directly in the fitting body 16 and / or at least one intermediate body.
• the connection between the electrical-acoustic transducer element 1 14 and the fitting body 1 16 and / or the optional compensation Layer can be made flexible so that the piezoelectric function is not affected by the thermal change of the matching body 1 16 or the compensating layer or by temperature shocks.
• the connection is preferably chosen to be sufficiently hard that there is sufficient acoustic coupling. As a rule, an epoxy-based material can be used for this purpose.
• the electrical connection between the electrodes of the electro-acoustic transducer element 1 14, for example of the piezo, and the contact clip, which may generally comprise one or more contact pins, can take place in various ways.
• a connection by means of wires, tapes, foil or strands can be made.
• another technique may be used as the contact instead of the aforementioned thermal compression welding.
• lead adhesives, soldering or wire bonding offer.
• the contact points or even the entire connection between the electrical-acoustic transducer element and the contact clip 144 and / or individual contact pins of this contact clip 144 can be covered with a hard protective compound, for example a glob-top mass and / or with soft silicone gel to protect them, for example against corrosion.
• the contact pins can in principle also be fixedly connected to one of the housing parts of the housing 1 18, for example as an insert part or as a lead frame and / or as overmolded parts.

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• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• General Physics & Mathematics (AREA)
• Electromagnetism (AREA)
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• 2009
  • 2009-10-29 DE DE102009046148A patent/DE102009046148A1/de not_active Withdrawn
• 2010
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  • 2010-09-10 WO PCT/EP2010/063294 patent/WO2011051042A1/de active Application Filing
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