Hydraulic Steering Arrangement Variable Damping Orifice
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Solution Overview
Problem
Articulated vehicles experience uncomfortable jerks during steering due to oscillations caused by the acceleration and deceleration of large masses, leading to unpleasant driver experiences.
Innovation Solution
A hydraulic steering arrangement with a variable damping orifice placed between the supply and return orifices, which reduces the flow rate to the steering motor at abrupt starts and counteracts inertia forces by adjusting pressure during steering and stopping, thereby minimizing jerks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hydraulic fluid is supplied to steer large masses in articulated vehicles, then steering function is achieved, but oscillations and jerks occur during steering start and stop
Solution Approach 1:
A damping orifice is arranged in the return flow path between the working port and return port to provide beforehand cushioning against oscillations and jerks. The damping orifice restricts the return flow of hydraulic fluid, creating a damping effect that counteracts the oscillations occurring during steering start and stop, thereby cushioning the harmful effects before they reach the steering motor.
Solution Approach 2:
The invention changes the flow resistance parameter by introducing a damping orifice in the return flow path. This orifice creates a pressure difference that varies with flow rate, dynamically adjusting the damping effect based on the steering conditions. The parameter change in flow resistance helps to suppress oscillations without compromising the overall steering performance.
2Ease of operation
If a damping orifice is added to reduce oscillations, then steering comfort is improved, but device complexity increases
Solution Approach 1:
The damping orifice is merged with the existing valve arrangement components, specifically integrated into the return flow path between the working port and return port. This merging approach allows the damping function to be added without requiring a completely separate system, thereby limiting the increase in device complexity while still achieving the desired steering comfort improvement.
3Object-affected harmful factors
If flow rate to steering motor is reduced at abrupt start, then impulse forces are minimized, but steering responsiveness may be affected
Solution Approach 1:
The damping orifice acts as an intermediary element in the hydraulic system, mediating between the supply pressure and the steering motor. It provides a controlled restriction that reduces impulse forces by damping the return flow, while still allowing sufficient fluid flow to maintain steering responsiveness. The orifice creates a balanced state where harmful impulse forces are reduced without completely blocking the hydraulic flow needed for responsive steering.
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 variable damping orifice significantly reduces the intensity of jerks and oscillations by managing hydraulic fluid flow and pressure, ensuring a comfortable steering experience by minimizing impulse and inertia forces.
Implementation Method 1
the parameters for the pressure drop over the return orifice are not changed compared with a situation without damping orifice
Implementation Method 2
the pressure at the return side of the steering motor will increase which counteracts the inertia forces from the other side of the steering motor
Implementation Method 3
the damping orifice between the two working ports or downstream the supply orifice and upstream the return orifice it will reduce the pressure in the forward side of the steering motor
Data Source
AI summary
A hydraulic steering arrangement (1) including a supply port arrangement having a supply port (2) and a return port (3), a working port arrangement having two working ports (4, 5), a supply flow path (7) between the supply port (2) and one of the working ports (4, 5), a return flow path (9) between the other of the working ports (5, 4) and the return port (3) and a valve arrangement having a spool/sleeve set, wherein the supply flow path (7) includes a supply orifice (A4) and the return flow path (9) comprises a return orifice (A5). Such a hydraulic steering arrangement should give a comfortable feeling when used in connection with an articulated vehicle. To this end a variable damping orifice (Adp) is arranged downstream the supply orifice (A4) and upstream the return orifice (A5).