1D ULTRASONIC TRANSDUCER UNIT FOR HAZARD IDENTIFICATION FOR A VEHICLE

Abstract

A 1D ultrasonic transducer unit for detecting danger for a vehicle, comprising a housing mounted on the vehicle, which includes at least three discrete ultrasonic transducers, designed to decouple sound waves at a corresponding working frequency between 20 kHz and 400 kHz into a gaseous medium, and a control unit, designed to control each ultrasonic transducer individually, two ultrasonic transducers directly adjacent to each other in each case having a distance, the 1D ultrasonic transducer unit having one sound channel per ultrasonic transducer, each with one inlet opening assigned to exactly one ultrasonic transducer and one outlet opening (26), the outlet openings being arranged along a straight line, a distance from directly adjacent outlet openings corresponding to no more than the full or half wavelength in the gaseous medium and being shorter than the corresponding distance.

Claims

1. A 1D ultrasonic transducer unit for detecting danger for a vehicle, the transducer unit comprising: a housing; at least three ultrasonic transducers; and a control unit designed to control each ultrasonic transducer individually, wherein each ultrasonic transducer has a transducer housing, a piezoelectric body arranged in the transducer housing and a sound decoupling layer arranged on an open end of the transducer housing for decoupling into a gaseous medium and being arranged in a fixed position in the housing, wherein each ultrasonic transducer is designed to emit and/or to receive a sound wave at a corresponding working frequency, wherein the working frequency of the sound waves being in a range from 20 kHz to 400 kHz, wherein two ultrasonic transducers directly adjacent to each other in each case in the housing have a distance of no more than 10 cm or no more than 5 cm or no more than 2 cm from the middle of the sound decoupling layer to the middle of the sound decoupling layer, wherein the 1D ultrasonic transducer unit has one sound channel for each ultrasonic transducer, wherein each sound channel has inlet opening and one outlet opening, wherein each sound decoupling layer is assigned to exactly one of the inlet openings, wherein the outlet openings are arranged along a straight line, wherein the outlet openings each are arranged in a first wall of the housing or the sound channels penetrating a wall of the housing not abutting the vehicle, wherein a distance from the middle of one outlet opening to the middle of a directly adjacent outlet opening corresponds to no more than the wavelength in the gaseous medium or no more than half the wavelength in the gaseous medium, wherein the distance between two directly adjacent outlet openings each being smaller than the distance of the ultrasonic transducers assigned to the corresponding inlet openings, wherein a ratio of a surface area of the outlet opening to a surface area of the inlet opening having a value between 0.30 and 1.2, and each sound channel having a length corresponding to at least the diameter of the inlet opening, wherein the housing is mounted on the vehicle, wherein the housing includes a movable cover device designed to close the outlet openings of all sound channels, and wherein the outlet openings of all sound channels are situated in a curved surface.

2. The 1D ultrasonic transducer unit according to claim 1, wherein the ratio of the surface area of the outlet opening to the surface area of the inlet opening has a value between 0.5 and 1.5 or between 0.9 and 1.1.

3. The 1D ultrasonic transducer unit according to claim 1, wherein each sound channel has a length from the sound decoupling layer of each ultrasonic transducer to the outlet opening of the assigned sound channel, and the length is an integral multiple of one eighth of the wavelength of the sound frequency or an integral multiple of half the wavelength of the sound frequency.

4. The 1D ultrasonic transducer unit according to claim 1, wherein each sound channel is made from a metal or a plastic or comprises a metal or a plastic.

5. The 1D ultrasonic transducer unit according to claim 1, wherein each ultrasonic transducer has a sound uncoupling layer between the decoupling layer and the transducer housing.

6. The 1D ultrasonic transducer unit according to claim 1, wherein the control unit is arranged entirely or partially in the housing.

7. The 1D ultrasonic transducer unit according to claim 1, wherein the housing of the 1D ultrasonic transducer unit is designed according to at least the IP 40 protection class.

8. The 1D ultrasonic transducer unit according to claim 1, wherein the housing has at least one signal interface for transmitting a measuring signal and/or a control signal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0043] FIG. 1A shows a side view of a first specific embodiment according to the invention of a 1D ultrasonic transducer unit;

[0044] FIG. 1B shows a top view of the first specific embodiment according to the invention of the 1D ultrasonic transducer unit;

[0045] FIG. 2 shows a sectional view of a specific embodiment according to the invention of a housing of a 1D ultrasonic transducer unit;

[0046] FIG. 3 shows a view of a further specific embodiment according to the invention of the sound channels;

[0047] FIG. 4 shows a view of a further specific embodiment according to the invention of the sound channels;

[0048] FIG. 5 shows a view of a further specific embodiment according to the invention of an individual sound channel; and

[0049] FIG. 6 shows a schematic view of different specific embodiments of an outlet surface of an sound channel.

DETAILED DESCRIPTION

[0050] The illustration in FIG. 1A shows a view of a first specific embodiment of a 1D ultrasonic transducer unit 10 according to the invention on a vehicle 100. In the illustration in FIG. 1B, vehicle 100, including 1D ultrasonic transducer unit 10, is shown in a top view. 1D ultrasonic transducer unit 10 is mounted on a rear side 102 of vehicle 100 in the middle and in a lower area, so that sound waves 11 generated by 1D ultrasonic transducer unit 10 propagate away from rear side 102 of the vehicle and are reflected by objects 13 situated in the propagation area, in particular in the area of the so-called sound cone.

[0051] According to an alternative specific embodiment, two 1D ultrasonic transducer units 10 are mounted in the upper corners of rear side 102 of vehicle 100 (illustrated by the dashed line) and are oriented in such a way that the sound waves propagate essentially downwardly along the rear side and/or at a small angle with respect to the rear side.

[0052] The top view in FIG. 1B further shows how sound waves 11 of 1D ultrasonic transducer unit 10 are pivotable or a main propagation direction of the generated sound waves may be set.

[0053] The illustration in FIG. 2 shows a sectional view of a housing 14 of an ultrasonic transducer unit 10. Three discrete ultrasonic transducers 12 are arranged in housing 14 along a planar rear wall 16 of housing 14. Each ultrasonic transducer 12 has its own transducer housing 18 and a sound decoupling layer 20. Each ultrasonic transducer 12 is spaced a distance A1 apart from the directly adjacent ultrasonic transducer(s) 12 from the middle of sound decoupling layer 20 to the middle of sound decoupling layer 20.

[0054] A sound channel 22 is assigned to each ultrasonic transducer 12, each sound channel 22 having an inlet opening 24 and an outlet opening 26. Inlet openings 24 are each arranged in front of or around one of ultrasonic transducers 12 in such a way that particular ultrasonic transducer 12 radiates into sound channel 22. Outlet openings 26 of sound channels 22 are arranged along a planar front wall 30 of housing 14 opposite the rear wall, or they penetrate front wall 30.

[0055] Two adjacent outlet openings 26 in each case have a distance A2 from the middle of outlet opening 26 to the middle of outlet opening 26. According to the invention, distance A2 of outlet openings 26 is smaller or equal in each case to distance A1 of assigned or associated ultrasonic transducers 12.

[0056] A length L1 from each sound decoupling layer 20 to outlet opening 26 of associated sound channel 22 is an integral multiple of one-eighth of the wavelength of the sound frequency.

[0057] Housing 14 also comprises a movable cover device 32. Cover device 32 is in a closed state in the illustrated exemplary embodiment. For this purpose, the cover device is arranged in front of front wall 30 of housing 14 having outlet openings 26, so that sound channels 22 are closed. In an opened state, for example by a lifting or sliding action, cover device 32 is no longer in front of front housing wall 30, and outlet openings 26 and outlet openings 26 are exposed.

[0058] In the exemplary embodiment illustrated in FIG. 3, sound channels 22 run in such a way that outlet openings 26 of all sound channels 22 are in a shared flat plane E1. In the illustrated exemplary embodiment, front wall 30 of housing 14 of 1D ultrasonic transducer unit 10 runs within plane E1. An area 34 of particular sound channel 22 still situated in front of inlet opening 24 of each sound channel 22 is designed in such a way that assigned ultrasonic transducer 12 in each case forms a precise fit within sound channel 22. For this purpose, each sound channel 22 has an inner diameter corresponding to outer diameter D1 in the area and an edge 36 serving as a stop.

[0059] A control unit, which is not illustrated, is designed to control each ultrasonic transducer 12 individually. Due to the time-shifted or phased control of individual ultrasonic transducers 12, 1D ultrasonic transducer unit 10 generates even ultrasonic waves having a main propagation direction (arrows), the main propagation direction or an angle between the main propagation direction and first plane E1 being settable with the aid of the phase shift between sound waves emerging from outlet openings 26 of the individual sound channels.

[0060] In the exemplary embodiment illustrated in FIG. 4, outlet openings 40 of all sound channels 22 are situated in a concavely curved surface F1.

[0061] An individual sound channel 22 is schematically shown in the illustration in FIG. 5, the differences with respect to FIGS. 1 through 4 being explained below.

[0062] Inlet opening 24 has a cross-sectional surface with a width x1 and a height y1; outlet opening 26 has a cross-sectional surface with a width x2 and a height y2.

[0063] Inlet opening 24 is provided with a circular design, i.e. width x1 and height y1 of the cross-sectional surface have the same value. Outlet opening 26, on the other hand, has an oval shape, so that width x2 of the cross-sectional surface is smaller than width y2.

[0064] In this case, width x2 of outlet opening 26 is smaller than width x1 of inlet opening 26. Height y2 of outlet opening 26, however, is preferably larger than height y1 of inlet opening 24. The height increase of sound channel 22 particularly preferably equals the decrease in the width of sound channel 22, in such a way that the surface area of the cross-sectional surface of inlet opening 24 corresponds to the surface area of the cross-sectional surface of outlet opening 26.

[0065] It is understood that width x2 of each outlet opening 26 must be smaller than the wavelength of the sound wave to be able to implement a distance from the middle of outlet opening 26 to the middle of a directly adjacent outlet opening 26 of no more than the wavelength of the sound frequency.

[0066] Multiple exemplary embodiments according to the invention of the cross-sectional surfaces of outlet openings 26 are shown schematically in the illustration in FIG. 6. In particular, shapes which have a ratio of width x2 to height y2 of approximately 1:5 are suitable so that the surface area of the cross-sectional surface of outlet opening 26 corresponds to the surface area of the cross-sectional surface of inlet opening 24.

[0067] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.