Tunable Hydraulic Bushing for Steering Gear Vibration Control
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Solution Overview
Problem
Existing bushings for mounting steering gears to vehicle frames fail to effectively attenuate smooth road shake vibrations, which can cause discomfort to vehicle operators, and do not provide sufficient flexibility during cornering and steering loads.
Innovation Solution
A tunable hydraulic bushing with an inertia track and pressure valve system that allows uninterrupted fluid communication between two chambers, where the pressure valve opens during loads greater than smooth road shake, enabling high fluid flow and accommodating larger displacements, while maintaining fluid equality under steady-state loads through narrow inertia tracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the bushing uses a fixed fluid communication path, then the structure is simple, but it cannot effectively attenuate smooth road shake vibrations while providing sufficient flexibility during cornering
Solution Approach 1:
The bushing transitions from a static fluid communication path to a dynamic system where the pressure valve opens or closes based on load conditions. The pressure valve responds to pressure differential changes, opening during cornering/steering loads to allow fluid flow and providing flexibility, while closing during smooth road shake to enable vibration attenuation. This dynamic adaptation resolves the contradiction between vibration attenuation and flexibility.
Solution Approach 2:
The system changes the fluid flow parameter dynamically by using the pressure valve to control the opening/closing of the fluid communication path. Under different load conditions (smooth road shake vs. cornering), the valve changes the fluid flow state, allowing the bushing to optimize its performance for either vibration attenuation or flexibility as needed.
2Object-affected harmful factors
If the pressure valve remains closed during smooth road shake, then vibration attenuation is improved, but fluid communication is blocked during cornering and steering loads
Solution Approach 1:
The pressure valve operates automatically based on the pressure differential across it, without external control. During smooth road shake, the lower pressure differential keeps the valve closed for vibration attenuation. During cornering/steering, the increased pressure differential automatically opens the valve to restore fluid communication and steering flexibility. This self-service mechanism resolves the contradiction without requiring external intervention.
Solution Approach 2:
The pressure valve responds to changes in the pressure differential parameter, using this physical parameter change to automatically switch between vibration attenuation mode (valve closed) and steering flexibility mode (valve open), thereby resolving the contradiction between these two operational requirements.
3Stability of the object's composition
If narrow inertia tracks are used, then fluid equality under steady-state loads is maintained, but fluid flow during high-load conditions is restricted
Solution Approach 1:
The fluid communication path is segmented into two distinct pathways: narrow inertia tracks that maintain fluid equality under steady-state conditions, and a pressure valve-controlled path that provides high-capacity fluid flow during high-load conditions. This segmentation allows each pathway to specialize in its optimal function, resolving the contradiction between stability and power.
Solution Approach 2:
The system dynamically switches between using the narrow inertia tracks (for stability under steady-state) and the pressure valve path (for power during high-load), based on the operating conditions. The pressure valve acts as a dynamic switch that opens to utilize the high-capacity path when needed, resolving the contradiction between maintaining fluid equality and enabling high fluid flow.
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 bushing effectively attenuates smooth road shake vibrations and allows necessary flexibility during cornering and steering, reducing operator discomfort and enhancing vehicle handling by tuning the inertia tracks and pressure valve to specific load thresholds.
Implementation Method 1
The inertia track provides uninterrupted fluid communication between the first cavity and the second cavity
Implementation Method 2
The pressure valve is configured to be closed during loads induced by smooth road shake and open during loads greater than smooth road shake
Implementation Method 3
The bushing effectively attenuates smooth road shake vibrations
Data Source
AI summary
A tunable hydraulic bushing mounts a steering gear to a vehicle frame member. The bushing is filled with a fluid and includes an inertia track and a pressure valve separating first and second fluid chambers or cavities. The inertia track provides uninterrupted fluid communication between the first cavity and the second cavity. The pressure valve is movable between an open position, which allows fluid communication though the pressure valve between the first cavity and the second cavity, and a closed position, which blocks fluid communication though the pressure valve between the first cavity and the second cavity. The pressure valve may be configured to be closed during loads induced by smooth road shake and open during loads greater than smooth road shake.