Vehicle Seat Air Spring Damping Control
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Solution Overview
Problem
Existing vehicle seat suspension systems fail to provide consistent comfort across varying road surfaces and terrain, as they either lack sufficient damping in comfort ranges or result in increased friction and reduced seating comfort due to fixed air spring characteristics and hydraulic actuator dependencies on vehicle electrical systems.
Innovation Solution
A suspension device with an air spring and control device that dynamically adjusts the supply and removal of additional volume based on speed and acceleration values, allowing for predeterminable force-displacement characteristics in stroke end areas, thereby optimizing comfort and damping across different terrains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a force-displacement air spring characteristic curve with a low gradient is set to achieve comfort in the middle position, then seating comfort is improved, but friction forces prevent the seat part from swinging back to the middle position
Solution Approach 1:
The patent applies dynamics by making the additional volume adjustable rather than fixed. The control device dynamically changes the additional volume based on the air spring's position and operating conditions, allowing the system to transition between different force-displacement characteristics. This enables the seat to have low gradient (comfortable) characteristics in the middle position range while switching to higher gradient characteristics in stroke end ranges to overcome friction and return to center.
Solution Approach 2:
The patent changes the parameter of additional volume to resolve the contradiction. By varying the additional volume as a function of air spring position and operating parameters, the system adjusts the force-displacement characteristic curve gradient dynamically. This allows optimization of both comfort (low gradient in middle range) and position stability (higher gradient in end ranges to overcome friction).
2Stability of the object's composition
If a greater restoring force is set to enable the seat part to swing back to the middle position, then position stability is improved, but comparatively hard damping is achieved in both middle and end lift ranges
Solution Approach 1:
The system dynamically adjusts the additional volume based on real-time operating conditions, allowing the restoring force to be optimized for different position ranges. In the middle position range, the additional volume is configured to provide low gradient for comfort, while in stroke end ranges, it increases the gradient to provide sufficient restoring force to overcome friction and return to center.
Solution Approach 2:
The patent applies local quality by creating different force-displacement characteristic zones within the air spring's stroke range. The middle position range has a low gradient (soft damping) optimized for comfort, while the stroke end ranges have a higher gradient (firm damping) optimized for position stability and friction overcoming. This spatial variation in damping characteristics resolves the contradiction between comfort and stability.
3Ease of operation
If an air spring characteristic curve with a low gradient in the comfort range is used, then comfort is improved, but end stops are reached in stroke end ranges during strong movements, reducing seating comfort
Solution Approach 1:
The control device dynamically adjusts the additional volume based on the air spring's position and operating conditions. When the air spring approaches stroke end ranges during strong movements, the system increases the additional volume to raise the gradient of the force-displacement characteristic, preventing end stop contact and maintaining damping performance throughout the full stroke range.
Solution Approach 2:
The system performs preliminary action by proactively adjusting the additional volume before the air spring reaches stroke end ranges. The control device monitors position and velocity, and in advance increases the additional volume when approaching the comfort range boundaries, ensuring sufficient restoring force is available to prevent end stop contact before it occurs.
4Adaptability or versatility
If a universal comfort range is set at the factory, then the system can be used for different road surfaces, but it can only be a compromise for effective suspension in different terrain
Solution Approach 1:
The patent transforms the static, factory-set universal comfort range into a dynamic, adaptive system. The control device continuously monitors operating parameters (position, velocity, acceleration) and adjusts the additional volume in real-time to optimize the force-displacement characteristic for current road conditions. This allows the system to adapt to different terrain types (tarred roads, dirt roads, fields) rather than relying on a fixed compromise setting.
Solution Approach 2:
The system implements feedback by using the control device to monitor air spring position, velocity, and acceleration, then adjusting the additional volume based on this information. This closed-loop control enables the suspension to automatically adapt to varying road surfaces and terrain conditions, optimizing comfort and effectiveness for each specific situation rather than using a universal compromise setting.
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 enhances driving comfort by adjusting the air spring's force-displacement characteristics to match terrain conditions, reducing post-oscillation and maintaining comfort through adaptive damping, regardless of the vehicle's speed and load conditions.
Implementation Method 1
at least one air spring arranged between a seat part and a lower part for height adjustment of the seat part
Implementation Method 2
a control device for controlling the supply and removal of at least one additional volume to or from the air spring as a function of predeterminable speed or acceleration values
Data Source
Figure 1
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AI summary
The device has a controller to control removal and discharging of additional volumes to or from an air spring. The removal and discharge is switched on or deactivated at predefinable speed/acceleration values of spring movement by the controller in a manner that distribution of a force path spring characteristic line has no or small gradient in lifting end areas of the spring during issuing or/and resetting spring movement in areas. An independent claim is also included for a method of suspension of a commercial vehicle seat.