Hydraulic Drive Device Pressure Compensating Valve Saturation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hydraulic driving systems for construction machines face issues during combined operations control, where significant differences in load pressure between actuators can lead to slowdowns or stops, as pressure compensating valves either excessively close or fail to fully close, disrupting fluid distribution and actuator performance.
Innovation Solution
The hydraulic driving system prevents full closure of pressure compensating valves with lower load pressure and ensures necessary fluid supply to higher load pressure actuators, maintaining appropriate fluid distribution and preventing actuator slowdowns or stops during saturation conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pressure compensating valves are configured to fully close when spool reaches stroke end, then differential pressure control precision is improved, but fluid supply reliability to actuators deteriorates during saturation conditions
Solution Approach 1:
The pressure compensating valve is designed to operate partially closed rather than fully closed during saturation conditions. The spool is positioned such that the valve maintains a small opening area that prevents excessive pressure differential while still allowing minimum fluid supply to actuators, avoiding complete closure that would cause actuator slowdowns or stops.
Solution Approach 2:
The invention changes the operational parameter of the pressure compensating valve from full closure to partial closure state. By adjusting the spool position and opening area characteristics, the valve maintains a controlled pressure differential that prevents actuator starvation during pump saturation, transforming the binary closed/open state into a controlled partial open state.
2Speed
If pressure compensating valves maintain target differential pressure during combined operations, then actuator speed control is improved, but fluid distribution uniformity deteriorates when pump saturation occurs
Solution Approach 1:
During pump saturation, the pressure compensating valve is designed to partially close rather than fully close, maintaining a minimum opening area that allows continued fluid supply to all actuators. This partial closure prevents complete disruption of fluid distribution while still providing sufficient pressure differential to maintain acceptable actuator speed control.
3Speed
If load-sensing control maintains target differential pressure between pump delivery pressure and actuator load pressure, then system responsiveness is improved, but actuator operability deteriorates under significant load pressure differences
Solution Approach 1:
The invention modifies the pressure compensating valve characteristics to prevent full closure during saturation. By changing the valve opening area versus spool position relationship, the system maintains a minimum pressure differential and fluid flow even when load pressure differences are significant, ensuring actuators remain operable while preserving load-sensing control responsiveness.
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 approach enhances combined-operations controllability by maintaining fluid supply to both high and low load pressure actuators, preventing slowdowns and ensuring efficient operation even under saturation conditions with significant load pressure differences.
Implementation Method 1
a fluid delivery pressure of the hydraulic pump becomes higher by a target differential pressure than a load pressure of an actuator
Implementation Method 2
a differential pressure (hereinafter referred to as the load-sensing differential pressure) between a fluid delivery pressure of a hydraulic pump and a load pressure of an actuator
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Control valves 100f, 100g, and 100h that reduce flow passage areas of parallel hydraulic fluid lines 41f, 41g, and 41h respectively when operating devices 34a, 34b for traveling are operated, are each disposed in the parallel hydraulic fluid line 41f, 41g, or 41h so that if saturation occurs during combined operations control likely to generate a significant difference in load pressure between any two actuators, the control valve prevents full closing of a pressure compensating valve lower in load pressure and thus prevents a slowdown and stop of the actuator undergoing the lower load pressure, and so that if saturation occurs during combined operations control likely to generate a particularly significant difference in load pressure between any two actuators, the control valve ensures a necessary supply of hydraulic fluid to the actuator higher in load pressure, thereby preventing a slowdown and stop of the actuator higher in load pressure.