Hydraulic Work Machine Valve Timing for Stable Turning Deceleration
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Solution Overview
Problem
Existing work machines experience unexpected increases in turning motor speed during transitions from combined operations involving both a work actuator and turning motor, leading to unintended angular acceleration, particularly during deceleration operations.
Innovation Solution
Implement a controller that performs asynchronization control by delaying the opening of the second work actuator control valve relative to the first, and synchronization control during turning deceleration, to manage hydraulic fluid flow rates and prevent unexpected speed changes in the turning motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the boom merging valve is opened only when the boom raising operation is large (by setting a higher pilot pressure threshold), then the speed of the boom raising motion can be increased when needed, but the rotation speed of the turning motor increases unexpectedly when transitioning from combination operation to single turning operation
Solution Approach 1:
The controller detects the operation state in advance and closes the boom merging valve before the boom direction selector valve when transitioning from combination operation to single turning operation. This preliminary action prevents hydraulic fluid from the second pump from flowing to the turning motor, avoiding unexpected speed increases before the operator intends them.
Solution Approach 2:
The controller continuously monitors the operation states of both the boom raising operation and turning operation, and dynamically adjusts the valve control based on the transition detection. This feedback mechanism ensures the boom merging valve is closed at the appropriate timing to prevent unintended turning motor acceleration while maintaining high boom raising speed when needed.
2Productivity
If the boom merging valve and boom direction selector valve have different opening characteristics, then the work actuator can operate at high speed when required, but the hydraulic fluid flow to the turning motor increases rapidly causing unexpected angular acceleration
Solution Approach 1:
The controller acts as an intermediary between the operator's input and the hydraulic valves. It monitors the operation states and intermediates the valve control by closing the boom merging valve before the boom direction selector valve during transitions, preventing the hydraulic fluid from the second pump from inadvertently flowing to the turning motor while still allowing high-speed operation when needed.
Solution Approach 2:
The valve control characteristics are made dynamic rather than fixed. The controller adjusts the effective opening characteristics of the boom merging valve based on the current operation state (combination operation vs. single turning operation), enabling the system to adapt to different operational requirements and prevent unexpected speed changes.
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 ensures the work actuator operates at high speeds when needed while preventing unexpected speed increases in the turning motor, maintaining operational control and operator intent.
Implementation Method 1
a first pump that discharges hydraulic fluid; a second pump that discharges hydraulic fluid separately from the first pump
Data Source
AI summary
A work machine includes first and second work actuator control valves, a work command adjuster that changes a work command to be input to the second work actuator control valve in accordance with a work adjustment command, and a controller including an adjustment command part that inputs the work adjustment command to the work command adjuster. The adjustment command part performs an asynchronization control in a single work operation state and a synchronization control in a combination operation state including a turning deceleration operation and a work operation. For the synchronization control, the adjustment command part generates the work adjustment command to render a minimum work operation amount to open the first work actuator control valve equal to a minimum work operation amount to close the second work actuator control valve and inputs it to the work command adjuster.