Steering Device Priority Valve Load Pressure Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing steering devices for construction/transport/farm machines, such as wheel loaders and tractors, face complexity and instability in prioritizing steering wheel operations due to the use of multiple control valves and sequence valves, leading to unintentional steering when both steering wheel and lever are operated simultaneously.
Innovation Solution
A steering device configuration that includes a steering cylinder, steering valve, pump, steering wheel control valve, electromagnetic control valve, steering wheel priority valve, and change-over valve with a two-port two-position configuration to prioritize steering wheel operations using load pressure, along with a mode change valve to block pilot oil passages and prevent accidental steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sequence valve and electromagnetic control valves are added to prioritize steering wheel operation, then steering wheel operation priority is achieved, but the control mechanism becomes complex
Solution Approach 1:
The patent combines the steering wheel priority function directly into the existing steering wheel control valve by adding a priority valve stage, rather than using separate sequence valves and electromagnetic control valves. This integration reduces the number of components while maintaining the steering wheel operation priority function.
Solution Approach 2:
The steering wheel control valve is designed to perform multiple functions: normal steering control and priority control for steering wheel operations. By making the control valve universal, the patent eliminates the need for dedicated priority control components, simplifying the overall mechanism.
2Reliability
If the sequence valve is operated by hydraulic oil from the steering wheel control valve, then steering wheel operation can be prioritized, but the operation becomes unstable depending on hydraulic oil flow amount
Solution Approach 1:
The patent replaces the hydraulic oil flow-dependent sequence valve operation with a pressure-dependent priority valve mechanism. The priority valve responds directly to load pressure generated during steering wheel operation, providing more stable and predictable priority control that is not affected by variations in hydraulic oil flow amount.
Solution Approach 2:
The patent changes the operating parameter for the priority control from hydraulic oil flow rate to load pressure. By using pressure as the triggering parameter instead of flow, the system achieves more stable operation that is directly correlated with the actual steering wheel operation state rather than variable hydraulic flow conditions.
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 simplifies the mechanism for prioritizing steering wheel operations, ensuring stable and reliable performance by blocking hydraulic oil supply to the steering cylinder when the steering wheel is operated, preventing accidental steering and reducing the risk of reverse rotation.
Implementation Method 1
a change-over valve for sensing load pressure generated when the steering wheel control valve is operated and for changing the steering wheel priority valve by the pressure
Implementation Method 2
when adopting the steering wheel control valve for a load reaction mechanism that transmits load reaction force of a road surface to the steering wheel through the steering cylinder
Data Source
AI summary
In order to provide a steering device for a construction/transport/farm machine which can be steered by means of a steering wheel operation and by means of a lever operation (or automatic steering) such that not only can a mechanism for prioritizing the steering wheel operation be achieved with a simple configuration, but the mechanism can also be caused to stably operate, the steering device is provided with: steering cylinders 1; a steering valve 2; a pump 3; a steering wheel control valve 4; an electromagnetic control valve 5 for lever/automatic steering; a steering wheel priority valve 6; and a change-over valve 7 which, upon sensing a load pressure generated when the steering wheel control valve 4 is operated, switches the setting of the steering wheel priority valve 6 by using the load pressure, wherein the change-over valve 7 for switching the setting of the steering wheel priority valve 6 has a two-port two-position configuration whereby a drain oil passage of the steering wheel priority valve 6 is closed by utilizing the load pressure generated when the steering wheel control valve 4 is operated.