Hydraulic System Steering Flow Supplement at Low Engine RPM
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Construction machinery hydraulic systems face difficulties in controlling the steering wheel when engine rpm is in a low range due to insufficient working fluid flow, making it hard to manage the steering wheel effectively.
Innovation Solution
A hydraulic system with a main pump, priority valve, load sensing pressure sensor, auxiliary pump, electric motor, and controller that supplements working fluid to the steering unit when flow is deficient, and stops the auxiliary pump when flow is excessive, ensuring optimal fluid distribution between the steering unit and work tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If working fluid is supplied to the steering unit first via a priority valve, then the steering unit receives adequate flow, but when engine rpm is low the absolute flow from the pump is deficient making steering control difficult
Solution Approach 1:
The system dynamically adjusts the flow distribution between steering unit and work tool based on real-time conditions. The controller monitors steering operation state and engine rpm, then dynamically opens the second check valve to supplement flow to the steering unit when needed, making the system adaptable to varying operational demands rather than using a fixed flow distribution.
Solution Approach 2:
The system changes the flow parameters by introducing an auxiliary flow path through the second check valve and flow dividing valve. When steering supplementation is needed, the system activates this alternative path to increase flow to the steering unit, effectively changing the flow distribution parameters without modifying the main pump output.
2Device complexity
If working fluid is distributed to both steering unit and work tool from one pump, then system complexity is reduced, but flow distribution becomes inefficient when steering flow is insufficient
Solution Approach 1:
The hydraulic system is segmented into multiple flow paths: a primary path through the priority valve for normal operation, and a secondary supplemental path through the second check valve and flow dividing valve. This segmentation allows the system to maintain simple overall structure while providing a dedicated backup path for steering flow supplementation when the primary path is insufficient.
Solution Approach 2:
The second check valve acts as an intermediary component that introduces additional working fluid into the steering supply line when needed. This intermediary element enables flow supplementation without requiring a complete redesign of the hydraulic system architecture, maintaining simplicity while improving steering response efficiency.
3Quantity of substance
If auxiliary pump supplements working fluid to the steering unit, then steering flow is adequate at low engine rpm, but energy loss increases from excessive fluid supply
Solution Approach 1:
The controller continuously monitors the steering operation state and engine rpm, using this feedback information to determine when auxiliary flow supplementation is actually needed. Based on this feedback, the controller selectively opens or closes the second check valve, ensuring auxiliary flow is provided only when the steering unit requires additional flow, thereby avoiding energy waste from continuous supplementation.
Solution Approach 2:
Instead of continuous operation, the auxiliary flow path is activated periodically or intermittently based on actual steering needs. The controller opens the second check valve only during periods when steering supplementation is required (such as low engine rpm conditions with steering input), and closes it when normal flow distribution suffices, creating a periodic rather than continuous supplementation pattern that reduces energy consumption.
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
This solution enhances steering wheel controllability by providing adequate fluid flow even at low engine rpm and minimizes energy loss by preventing excessive fluid supply.
Implementation Method 1
a priority valve 22 installed in a supply passage for the working fluid discharged from the main pump 10, for dividing and supplying the working fluid discharged from the main pump 10 to the steering unit 20 and the main control valve 30, to correspond to the load sensing pressure
Implementation Method 2
an auxiliary pump 40 for supplementing working fluid to the supply passage supplying the working fluid divided by the priority valve 22 to the steering unit 20
Implementation Method 3
a load sensing pressure sensor 60 for sensing a load sensing pressure of the steering unit 20
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present invention relates to a hydraulic system for construction machinery, which is applied to construction machinery provided with a steering unit (20) for controlling steering of equipment, and a main control valve (30) for controlling operating of a work tool, and includes: a main pump (10) for discharging working fluid supplied to the steering unit (20) and the main control valve (30); a load sensing pressure sensor (60) for sensing a load sensing pressure of the steering unit (20); a priority valve (22) installed in a supply passage for the working fluid discharged from the main pump (10), for dividing and supplying the working fluid discharged from the main pump (10) to the steering unit (20) and the main control valve (30), to correspond to the load sensing pressure; an auxiliary pump (40) for supplementing working fluid to the supply passage supplying the working fluid divided by the priority valve (22) to the steering unit (20); an electric motor (50) for operating the auxiliary pump (40); and a controller (80) for operating the electric motor (50) when the load sensing pressure is greater than a reference load sensing pressure, and additionally supplying working fluid discharged from the auxiliary pump (40) to the steering unit (20).