Hydraulic Steering Circuit with Proportional Bypass Valve
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Solution Overview
Problem
Hydraulic steering circuits for vehicles with two axles face challenges in maneuverability due to the need to switch between steering modes optimized for low and high speeds, leading to instability at intermediate speeds, and similar issues occur in hydraulically driven robots with multiple arms.
Innovation Solution
A hydraulic circuit with a first fluid path and a second fluid path providing parallel communication, featuring a first proportional bypass control valve to control fluid flow through a first hydraulic displacement unit, and a third fluid path with a second hydraulic displacement unit, allowing for versatile steering control via an electronic control unit that adjusts fluid flow based on sensors and feedback algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the hydraulic steering circuit switches between first and second steering modes optimized for low and high speeds, then the vehicle stability at high speeds and maneuverability at low speeds are improved, but the vehicle stability at intermediate speeds deteriorates
Solution Approach 1:
The hydraulic steering circuit dynamically adjusts the steering ratio in real-time based on vehicle speed, transitioning smoothly between different steering modes rather than switching abruptly. The control unit continuously modulates the hydraulic flow to maintain optimal steering characteristics across the entire speed range, including intermediate speeds where stability was previously compromised.
Solution Approach 2:
The system changes the steering ratio parameter continuously as a function of vehicle speed. At low speeds, a higher steering ratio provides enhanced maneuverability, while at high speeds, a lower steering ratio maintains stability. The transition between these parameter states occurs progressively through intermediate values, ensuring stable vehicle behavior at all speeds.
2Device complexity
If a single hydraulic pump drives multiple hydraulic displacement units, then the device complexity is reduced, but the control precision and maneuverability deteriorate
Solution Approach 1:
A proportional control valve acts as an intermediary between the single hydraulic pump and the multiple hydraulic displacement units. This valve precisely regulates the hydraulic flow distribution to each displacement unit based on control signals, enabling independent and precise control of each actuator while maintaining system simplicity.
Solution Approach 2:
The single hydraulic pump serves multiple functions by supplying hydraulic fluid to different displacement units through the proportional control valve. The control valve enables the pump to effectively serve multiple actuators with different flow requirements, maintaining maneuverability control precision despite the simplified single-pump architecture.
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 maneuverability across various speeds by allowing for intermediate steering modes, improving vehicle stability and robot arm control by dynamically adjusting fluid flow and displacement ratios, maintaining optimal performance regardless of mechanical loads and ground conditions.
Implementation Method 1
the second fluid path comprises at least a first proportional bypass control valve (8) for controlling a bypass fluid flow in the second fluid path (7)
Data Source
AI summary
A hydraulic circuit, in particular to a hydraulic steering circuit for steering at least one vehicle axle, the hydraulic circuit including a first fluid path having a first end and a second end and providing fluid communication or selective fluid communication between the first end and the second end of the first fluid path; and a second fluid path providing fluid communication or selective fluid communication between the first end of the first fluid path and the second end (2) of the first fluid path, in parallel to the first fluid path or to a section thereof. In some aspects, the first fluid path includes a first hydraulic displacement unit; and the second fluid path includes at least a first proportional bypass control valve for controlling a bypass fluid flow in the second fluid path. The hydraulic steering circuit may be part of a driveline for a vehicle.