Ultrasonic Sensor Decoupling Ring for Bumper Mounting
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Solution Overview
Problem
Concealed ultrasonic sensors in vehicles face challenges with unwanted ultrasonic wave reverberation, leading to spurious echoes and functional failures in driver assistance systems, as a significant portion of sound energy is radiated backwards and reflected, impairing the accuracy of systems like automatic parking assistance.
Innovation Solution
An ultrasonic sensor device with a pot-shaped membrane, a decoupling ring around the membrane, and a stiffening element, featuring a circumferential first radial decoupling area and a second radial decoupling area with an axial end face that axially contacts the stiffening element, effectively sealing the membrane and reducing rearward sound propagation, utilizing a soft, elastic material for the decoupling ring and a damping disk to minimize reverberation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the ultrasonic sensor is installed concealed behind the bumper, then the visual appearance of the vehicle is improved, but unwanted ultrasonic wave reverberation occurs causing spurious echoes
Solution Approach 1:
The harmful reverberation effect is extracted and isolated by introducing a decoupling ring that separates the membrane vibration from the bumper structure, preventing the propagation of unwanted ultrasonic waves while maintaining the concealed installation behind the bumper
Solution Approach 2:
A decoupling ring made of soft elastic material is introduced as an intermediary element between the membrane and the bumper structure. This intermediary absorbs and dissipates ultrasonic energy, preventing reverberation while allowing the sensor to remain concealed behind the bumper for aesthetic purposes
2Reliability
If a stiffening element is added around the membrane, then the resonating area of the bumper is limited, but the positioning and bonding tolerances become significantly more stringent
Solution Approach 1:
The material parameter of the decoupling ring is changed to soft elastic material, which provides vibration control and bumper resonance limitation while being tolerant of manufacturing variations in positioning and bonding, thus maintaining reliability without requiring stringent precision
3Reliability
If the decoupling ring is pressed axially between the housing and the stiffening element, then the acoustic sealing towards the rear is improved, but the assembly complexity increases
Solution Approach 1:
The decoupling ring is designed to serve multiple functions simultaneously: it provides acoustic sealing, acts as a mechanical stop, and enables simple snap-fit assembly. By merging these functions into a single component, acoustic sealing is achieved without increasing assembly complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces ultrasonic wave reverberation, preventing unwanted echoes and ensuring reliable operation of driver assistance systems by effectively sealing the membrane and minimizing sound propagation into the vehicle interior, while maintaining mechanical connection and vibration control.
Implementation Method 1
a decoupling ring which is arranged around the membrane in contact with an outer circumference of the membrane... The decoupling ring has a circumferential first radial decoupling area that bears against the outer circumference of the membrane... and a second radial decoupling area with an axial end face that bears against an axial end face of the stiffening element
Implementation Method 2
utilizing a soft, elastic material for the decoupling ring
Implementation Method 3
a stiffening element, which is arranged around the decoupling ring and is preferably formed of ceramic... so that the resonating area of the paneling part can be limited to a defined area
Implementation Method 4
an ultrasonic sensor which has a pot-shaped membrane for emitting and/or receiving ultrasonic signals... the front side of the membrane, via which ultrasonic waves are emitted and received
Implementation Method 5
the ultrasonic sensor is located on a rear side of the bumper, so that the front side of the membrane is brought into contact with the rear side of the bumper - if necessary via an additional assembly cover. With ultrasonic sensors installed in this way directly behind the bumper, the ultrasonic signals are sent and received through the material of the bumper
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to an ultrasonic sensor device (1) for a motor vehicle, comprising an ultrasonic sensor (2), which has a pot-shaped membrane (21) for emitting and/or receiving ultrasonic signals, a decoupling ring (6), which is arranged around the membrane (21) and lies against an outer circumference (34) of the membrane (21), and a stiffening element (13), which is arranged around the decoupling ring (6), wherein the decoupling ring (6) has a circumferential first radial decoupling region (32) that lies against the outer circumference (34) of the membrane (21) and a second radial decoupling region (33) having an axial end face (37), which lies against an axial end face (38) of the stiffening element (13).