Vehicle Bonnet Damping Device with Adjustable Piston Rod
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Solution Overview
Problem
Existing damping devices for motor vehicle front flaps, when raised for pedestrian protection, often result in high kinetic energy that can cause damage and inadequate damping, leading to potential injuries and noise issues due to sudden damping force onset and limited adjustability.
Innovation Solution
A damping device with a freely adjustable piston rod or guide cylinder within a predetermined initial adjustment path, articulated to a pivot lever, providing a controlled damping effect that starts only when the piston rod comes to rest against a stop, eliminating the need for a pressurized gas medium and allowing precise adjustment of the damping force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the front flap is raised quickly into the pedestrian protection position, then the response time is reduced and pedestrian safety is improved, but the kinetic energy of the flap increases causing damage to the flap or its pivot points
Solution Approach 1:
The damping device is pre-configured with a freely adjustable piston rod or guide cylinder that moves without resistance during the initial adjustment path. This preliminary phase allows the flap to be rapidly positioned into the pedestrian protection zone before the damping effect engages, ensuring quick response while preventing structural damage once the stop is reached
2Object-affected harmful factors
If a damping element is provided to reduce damping effect, then pedestrian protection is improved, but the front flap may oscillate around the pedestrian protection position reducing damping effectiveness
Solution Approach 1:
The damping device transitions from a static damping force application to a dynamic system where the piston rod or guide cylinder is freely adjustable during the initial phase. The damping effect is dynamically engaged only after the predetermined initial adjustment path is completed, allowing the flap to first reach the protective position quickly, then stabilize without oscillation once damping begins
3Device complexity
If a band or rope is used as a damping element, then the structure is simple, but the damping force onset is sudden and can stimulate front flap oscillation
Solution Approach 1:
The damping device is segmented into distinct functional zones: a freely adjustable initial adjustment path where no damping occurs, and a subsequent damping zone where the damping element engages. This segmentation allows the simple band or rope structure to be used while preventing sudden damping force onset by ensuring the damping element only engages after the initial path is completed, eliminating flap oscillation stimulation
4Reliability
If the damping element is constantly connected to the front flap or body, then the damping effect is continuous, but the adjustment range is limited and adjustability is reduced
Solution Approach 1:
The damping device employs a dynamic connection system where the piston rod or guide cylinder can move freely within a predetermined initial adjustment path relative to the front flap or body. This dynamic arrangement allows the damping element to remain connected while providing an extended adjustment range, as the freely adjustable component can traverse the initial path without engaging damping, then engage when needed for reliable damping effect
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
Enables a more precise and controlled damping effect, preventing the front flap from overshooting the pedestrian protection position while allowing rapid adjustment, thus reducing damage and noise, and ensuring effective impact attenuation.
Implementation Method 1
the damping piston compresses the volume of gas in the guide cylinder, which flows through a throttle opening into the pressure chamber enclosed by the outer cylinder, which causes a damping force on the front flap
Implementation Method 2
The tape or rope is intended to cause a damping force on the front flap by stretching beyond the extended position
Data Source
Figure 1
Figure 2
AI summary
The device has a piston rod (5) axially guided from a damping piston to outward through an opening in a guide cylinder (4). The piston, the rod or the guide cylinder is freely moved in an outer cylinder (7) axially within an adjusting path between stops (8, 9). The rod, the guide cylinder or the outer cylinder is hinged at a front flap (1) or at a part that is movably or fixedly connected with the front flap. The rod, the cylinder guide or the outer cylinder is hinged at a body (2) of a motor vehicle or at a hinge part that is fixedly or movably connected with the body.