Piezoceramic Ultrasonic Transducer

Abstract

A piezoceramic ultrasonic transducer for a vehicle includes: a disc-shaped piezoceramic oscillator configured to generate ultrasonic waves; a printed circuit board configured to provide electric power to the disc-shaped piezoceramic oscillator; and a composite elastomeric element arranged between the disc-shaped piezoceramic oscillator and the printed circuit board, the composite elastomeric element being configured to support the piezoceramic oscillator on the printed circuit board. The composite elastomeric element includes a first elastomeric compound element and a second elastomeric compound element. The first elastomeric compound element includes a first temperature dependent viscoelasticity and supports the piezoceramic oscillator on the printed circuit board in a first temperature range and the second elastomeric compound element includes a second temperature dependent viscoelasticity and supports the piezoceramic oscillator on the printed circuit board in a second temperature range different from the first temperature range.

Claims

1. A piezoceramic ultrasonic transducer (10) for a vehicle, comprising: a disc-shaped piezoceramic oscillator (12) configured to generate ultrasonic waves; a printed circuit board (14) configured to provide electric power to the disc-shaped piezoceramic oscillator (12); and a composite elastomeric element (16) arranged between the disc-shaped piezoceramic oscillator (12) and the printed circuit board (14), the composite elastomeric element (16) being configured to support the piezoceramic oscillator (12) on the printed circuit board (14), wherein the composite elastomeric element (16) includes a first elastomeric compound element (20) and a second elastomeric compound element (22), wherein the first elastomeric compound element (20) includes a first temperature dependent viscoelasticity and supports the piezoceramic oscillator (12) on the printed circuit board (14) in a first temperature range and the second elastomeric compound element (22) includes a second temperature dependent viscoelasticity and supports the piezoceramic oscillator (12) on the printed circuit board (14) in a second temperature range different from the first temperature range.

2. The piezoceramic ultrasonic transducer (10) of claim 1, wherein the first elastomeric compound element (20) and the second elastomeric compound element (22) are arranged in an alternating manner.

3. The piezoceramic ultrasonic (10) transducer of claim 2, wherein the composite elastomeric element (16) has a disc-shaped main body (23) and the first elastomeric compound element (20) and the second elastomeric compound element (22) are concentric annular elements with diameters different from one another.

4. The piezoceramic ultrasonic transducer (10) of claim 1, wherein the first temperature range is in a range of about −40° C. to about +20° C., and the second temperature range is in a range of about +20° C. to about +90° C.

5. The piezoceramic ultrasonic transducer (10) of claim 2, wherein the first temperature range is in a range of about −40° C. to about +20° C., and the second temperature range is in a range of about +20° C. to about +90° C.

6. The piezoceramic ultrasonic transducer (10) of claim 3, wherein the first temperature range is in a range of about −40° C. to about +20° C., and the second temperature range is in a range of about +20° C. to about +90° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In the drawings:

[0016] Exemplary embodiments of the invention are described by the accompanying drawings, which are incorporated herein and constitute a part of the specification.

[0017] FIG. 1 is a schematic view of a piezoceramic ultrasonic transducer according to a first embodiment of the present invention;

[0018] FIG. 2 is a schematic cross-sectional view along line A-A of the piezoceramic ultrasonic transducer of FIG. 1; and

[0019] FIG. 3 is a schematic cross-sectional view of another embodiment of a piezoceramic ultrasonic transducer according to the present invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0020] Within this disclosure, the same reference numbers refer to the same components.

[0021] FIG. 1 shows a schematic view of a piezoceramic ultrasonic transducer 10 of a first embodiment of the present invention. The piezoceramic ultrasonic transducer 10 may be used for distance measurements, for example in air springs, but also for distance measuring systems in vehicles.

[0022] The piezoceramic ultrasonic transducer 10 includes a disc-shaped piezoceramic oscillator 12 for generating ultrasonic waves and a printed circuit board (PCB) 14 for providing electric power to the piezoceramic oscillator 12. The piezoceramic ultrasonic transducer 10 further includes a composite elastomeric element 16 which is arranged between the oscillator 12 and the PCB 14 for supporting the oscillator 12 on the PCB 14. Electrical connections 18 are provided within composite elastomeric element 16 for electrical connecting the oscillator 12 with the PCB 14. These electrical connections 18 may be, for example, very thin wires.

[0023] As can be seen in FIG. 1, the composite elastomeric element 16 includes two elastomeric compound elements. A first elastomer compound element 20 is arranged next to a second elastomeric compound 22. The first elastomeric compound element 20 is selected such that it includes a first temperature dependent viscoelasticity and provides a main support for the oscillator 12 on the PCB 14 in a first temperature range, for example, in range between about −40° C. to about +20° C. Therefore, the first elastomeric compound element 20 may also be referred to as “low-temperature elastomeric compound element”. The second elastomeric compound element 22 is selected such that it includes a second temperature dependent viscoelasticity and provides a main support for the oscillator 12 on the PCB 14 in a second temperature range, for example, in a range between about +20° C. to about +90° C. Therefore, the second elastomeric compound element 22 may also be referred to as “high-temperature elastomeric compound element”. For this, the low-temperature elastomeric compound element 20 may be made of a different material or different material composition than the high temperature elastomeric compound element 22.

[0024] As can be further seen in FIG. 1, the first and second elastomeric compound elements 20, 22 are arranged alternately within composite elastomeric element 16. Thus, composite elastomeric element 16 comprises alternating sections of low- and high-temperature elastomeric compound elements 20, 22. The number of alternating sections of low- and high-temperature elastomeric compound elements 20, 22 can be adapted to the application at hand. Also, the composite elastomeric element 16 includes a disc-shaped main body 23 extending in an axial direction along an axis 24 and extending in a radial direction perpendicular to axis 24. Thus, depending on the application at hand, also the height (measured in axial direction of the disc-shaped main body 23) of the disc-shaped main body 23 as well as the thickness (measured along the radial direction of disc-shaped main body 23) of each section of low- and high-temperature elastomeric compound elements 20, 22 can be adapted.

[0025] Referring now to FIG. 2, a schematic cross-sectional view of piezoceramic ultrasonic transducer 10 of FIG. 1 along line A-A is shown.

[0026] As can be seen, both first and second elastomeric compound elements 20, 22 are concentric annular elements with different diameters (measured in a radial direction of disc-shaped main body 23, i.e., in a direction perpendicular to axis 24). Thus, either the low-temperature elastomeric compound element 20 or the high-temperature elastomeric compound element 22 provides an annular support surface for supporting oscillator 12 on PCB 14 in the respective low- or high-temperature range.

[0027] Referring now to FIG. 3, a schematic cross-sectional view of another embodiment of piezoceramic ultrasonic transducer 10 of FIG. 1 along line A-A is shown.

[0028] As can be seen, in the piezoceramic ultrasonic transducer 10 according to FIG. 3, low- and high-temperature elastomeric compound elements 20, 22 are not concentric annular elements with different diameters (as shown in FIG. 2), but alternating columns or pillars. The embodiment shown in FIG. 3 is another example for alternately arranged low- and high-temperature elastomeric compound elements 20, 22. Further appropriate embodiments of alternately arranged low- and high-temperature elastomeric compound elements 20, 22 are conceivable, depending on the application at hand.

[0029] The piezoceramic ultrasonic transducer 10 according to the present invention ensures a reliable performance over low- and high-temperature ranges by having a composite elastomeric element with low- and high-temperature elastomeric compound elements. Moreover, as low- and high-temperature elastomeric compound elements are selected such that the respective temperature dependent viscoelasticities are best within either the low- or the high-temperature range, a long-lasting and reliable support of the oscillator 12 on the PCB 14 as well as a good mechanical vibratory decoupling between the oscillator 12 and the PCB 14 are ensured.

[0030] Although only two different (i.e., a low- and a high-temperature) elastomeric compound elements are shown in connection with FIGS. 1 to 3, it is conceivable that composite elastomeric element 16 may include more than two different elastomeric compound elements. For example, in other embodiments not shown, composite elastomeric element 16 may include three or more different elastomeric compound elements which each have a different temperature dependent viscoelasticity suited to the application at hand.

[0031] Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.