Hydraulic Work Machine Valve Control 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 operation states to single turning operations, leading to unintended deceleration issues and energy inefficiency.
Innovation Solution
A work machine with a controller that performs asynchronization and synchronization control to manage the opening and closing of valves between hydraulic pumps and actuators, ensuring the turning motor's speed is controlled by adjusting the flow rate of hydraulic fluid based on operation commands, preventing unexpected speed increases during deceleration and optimizing power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the boom merging valve is opened only when the boom raising operation is large (difference between valve opening characteristics), then the speed of the boom raising motion can be increased, but the rotation speed of the turning motor increases unexpectedly when transitioning from combination operation to single turning operation
Solution Approach 1:
The controller determines in advance whether a combination operation is being performed and proactively controls the valve closing sequence accordingly. When a combination operation is detected, the controller ensures the first control valve closes before the second control valve, preventing the harmful effect before it can occur. This preliminary determination and preparation of control strategy resolves the contradiction by anticipating the operational context.
Solution Approach 2:
The controller continuously monitors the operation state (combination operation vs. single operation) and adjusts the valve control strategy based on this feedback. When the operation state changes from combination to single operation, the controller receives feedback about this change and modifies the valve closing sequence accordingly, ensuring the first valve closes before the second valve to prevent unexpected turning motor speed increases.
2Power
If the second pump supplies hydraulic fluid to both the work actuator and turning motor, then high power is available for work operations, but energy is wasted when the work operation is reduced in combination operation states
Solution Approach 1:
The system dynamically adjusts the valve control strategy based on the operational context. In combination operation states, the controller modifies the closing sequence to close the first valve before the second valve when reducing work operation, thereby dynamically redirecting hydraulic fluid flow to prevent energy waste. This dynamic adaptation allows the system to maintain high power availability when needed while minimizing energy loss during deceleration phases.
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 effectively maintains high work actuator speed while preventing unexpected turning motor speed increases, ensuring operator intent is respected and reducing energy consumption during deceleration operations.
Implementation Method 1
a first pump that discharges hydraulic fluid; a second pump that discharges hydraulic fluid separately from the first pump
Data Source
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AI summary
Provided is a work machine capable of restraining a turning motor from speed increase at unexpected timing for an operator. The work machine includes: first and second work actuator control valves (51, 52); a work command adjuster (60) that changes a work command to be input to the second work actuator control valve (52) in accordance with a work adjustment command; and a controller (90) including an adjustment command part that inputs the work adjustment command to the work command adjuster (60). 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 (51) equal to a minimum work operation amount to close the second work actuator control valve (52) and inputs it to the work command adjuster (60).