Hydraulic Steering Priority Valve with Gas-Charged Accumulator
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Solution Overview
Problem
Existing hydraulic steering control systems for earthmoving and industrial mobile vehicles require large variable displacement pumps and additional backup sources, leading to space and cost inefficiencies due to the need for substantial equipment and additional features to ensure continuous steering control.
Innovation Solution
A hydraulic steering control system utilizing a gas-charged accumulator as the primary fluid source, with a priority valve that maintains a minimal pressure drop and adjusts flow based on operator input, reducing the size and energy requirements of the secondary pump and enhancing space utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large variable displacement pump is used as the primary hydraulic fluid source, then sufficient fluid supply for steering control is ensured, but the system size and manufacturing cost increase
Solution Approach 1:
The hydraulic system is segmented into two independent fluid sources: a small electric pump for general hydraulic functions and a gas-charged accumulator specifically for steering control. This segmentation allows each component to be optimized for its specific function, eliminating the need for a large variable displacement pump while ensuring reliable steering control through the accumulator's stored pressurized fluid.
Solution Approach 2:
The gas-charged accumulator is pre-charged with pressurized nitrogen and contains a reservoir of hydraulic fluid ready for immediate deployment. This preliminary action ensures that when steering control is needed, pressurized fluid is already available without requiring a large pump to generate pressure on demand, thus reducing pump size while maintaining reliability.
2Reliability
If backup fluid sources are added to ensure continuous steering control, then steering reliability is improved, but space requirements and device complexity increase
Solution Approach 1:
The system merges the backup fluid source function into the primary accumulator design. The gas-charged accumulator serves dual purposes: it provides the primary pressurized fluid source for steering control and simultaneously acts as the backup source. This integration eliminates the need for separate backup pumps or reservoirs, reducing space requirements while ensuring continuous steering control.
Solution Approach 2:
The gas-charged accumulator is designed as a multi-functional component that provides both primary steering control fluid supply and backup fluid source capabilities. The accumulator can independently supply pressurized fluid for steering operations without requiring additional dedicated backup equipment, thus conserving machine interior space while maintaining steering control continuity.
3Use of energy by stationary object
If a gas-charged accumulator is used as the primary fluid source with a small electric pump, then space utilization is improved and energy consumption is reduced, but system complexity increases due to the priority valve and pressure differential requirements
Solution Approach 1:
A priority valve is introduced as an intermediary component between the accumulator and the steering flow amplifier. This valve automatically maintains the required pressure differential (10-50 psi) without requiring complex electronic controls or large pumps. The priority valve simplifies the system by providing automatic pressure regulation, eliminating the need for complex pressure control circuits while enabling the use of a small electric pump with the accumulator.
4Stress or pressure
If priority valve flow restriction is used to maintain pressure differential, then accumulator pressure control is improved, but fluid flow to the steering circuit is restricted
Solution Approach 1:
The priority valve incorporates a spring-loaded mechanism that dynamically adjusts flow restriction based on real-time pressure differential conditions. When the pressure differential between the accumulator and steering circuit exceeds the specified range (10-50 psi), the spring force automatically restricts flow to reduce accumulator pressure. When the differential is within range, the valve opens fully to maximize fluid flow. This dynamic adjustment maintains optimal pressure control while minimizing flow restriction during normal operation.
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 system achieves efficient fluid supply and reduced equipment size by using accumulators as the primary source, allowing for compact design and reduced energy consumption while maintaining reliable steering control.
Implementation Method 1
an accumulator holding a quantity of pressurized steering fluid
Implementation Method 2
maintains a minimal pressure drop and adjusts flow based on operator input
Data Source
AI summary
A hydraulic fluid supply portion of a hydraulic steering control system may include an accumulator holding a quantity of pressurized steering fluid, and a priority valve. The priority valve may have a priority supply inlet port fluidly connected to the accumulator for receiving pressurized steering fluid from the accumulator, and a priority supply outlet port fluidly connected to a steering flow amplifier circuit. The priority valve may have a normally open position with a minimal pressure drop between the priority supply inlet port and the priority supply outlet port, and a flow restriction position where fluid flow between the ports is restricted. A load signal line from a steering control circuit to the priority valve may bias the priority valve toward the normally open position in response to an operator steering command to provide pressurized steering fluid to the steering flow amplifier circuit.