Excavator Boom Anti-Drop Valve Pressure Control for Range Limiting
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Solution Overview
Problem
The variation in pilot pressure to release the anti-drop function of excavator anti-drop valves due to individual differences leads to deviations in the start or stop timing of boom operations, reducing control accuracy when restricting work device operations to a predetermined range.
Innovation Solution
A work machine with a multi-joint type work device and anti-drop valves, equipped with a controller that calculates and controls release pressure for the anti-drop function based on information related to a restriction function, ensuring accurate operation within a predetermined range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the anti-drop valve uses a fixed pilot pressure to release the anti-drop function, then the structure is simple, but the control accuracy deteriorates due to individual differences in pilot pressure magnitude
Solution Approach 1:
The invention makes the release pressure dynamic by adjusting it according to the restriction function settings. The controller calculates the required release pressure based on the target position and current position of the work device, allowing the anti-drop valve to release at different pressure levels depending on the operational context, thereby improving control accuracy without complicating the basic valve structure
Solution Approach 2:
The invention changes the parameter of release pressure from a fixed value to a variable value that depends on the restriction function parameters. By adjusting the release pressure parameter according to the target position and current position, the system achieves precise control while maintaining a relatively simple anti-drop valve structure
2Reliability
If the pilot pressure is increased to ensure reliable anti-drop function release, then the reliability improves, but the control precision deteriorates due to overshooting the target position
Solution Approach 1:
The invention dynamically adjusts the release pressure to match the specific operational requirements. Instead of using a high fixed pressure that guarantees release but causes overshooting, the system calculates the precise release pressure needed based on the target position and current position, ensuring reliable release without exceeding the target position
Solution Approach 2:
The invention implements a feedback mechanism where the controller continuously monitors the current position of the work device and the target position, then adjusts the release pressure accordingly. This feedback loop ensures that the anti-drop function releases reliably at the correct moment without causing position overshooting
Data Source
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AI summary
The present invention provides a work machine that can improve the accuracy of control to limit the operation of the work device within a predetermined range. The excavator includes a control valve that controls the flow of pressure oil to the boom hydraulic cylinder, multiple pilot solenoid valves that generate and output pilot pressure to operate the control valve, a controller with a limiting function that controls the multiple pilot solenoid valves to restrict the operation of the work device to a predetermined range, anti-drop valves with an anti-drop function to prevent the boom from falling, and solenoid valves that output release pressure to release the anti-drop function of the anti-drop valves. The controller calculates the release pressure for the anti-drop valves based on information related to the limiting function and controls the solenoid valves to output the calculated release pressure to the anti-drop valves as a signal to release the anti-drop function.