Hydraulic Lever Dead Zone Control for Stable Construction Machine Speed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In construction machines with hydraulic systems, unintentional fine operations of control levers can lead to a decrease in actuator speed and work speed due to pump reconnection, impairing operability.
Innovation Solution
A construction machine with multiple closed circuit pumps, regulators, actuators, selector valves, and a controller that adjusts pump displacements and flow rates to prevent pump reconnection and smooth operation by implementing a composite dead zone and operation region control system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If selector valves are used to switch pump connections to ensure operability of multiple actuators, then adaptability is improved, but unintentional fine operations cause pump reconnection that decreases actuator speed and work speed
Solution Approach 1:
The controller receives operation signals from operation devices, calculates demanded flow rates based on operation amounts and predetermined characteristics, and controls selector valves and regulators accordingly. This feedback mechanism ensures that pump connections are switched only when genuinely needed, preventing unintentional reconnection that would decrease actuator speed.
Solution Approach 2:
The system changes the connection parameters of pumps to actuators dynamically based on calculated demanded flow rates. By adjusting which pumps are connected to which actuators based on real-time flow rate requirements, the system maintains optimal actuator speed while ensuring adaptability for multiple actuator operations.
2Power
If multiple pumps are connected to a single actuator to increase power output, then power is improved, but fine operation of another actuator causes pump reconnection that decreases work speed
Solution Approach 1:
The system dynamically adjusts pump connections based on real-time operation requirements. When one actuator requires high power from multiple pumps, the system maintains these connections while enabling fine operation of other actuators through controlled pump switching only when genuinely needed, thus maintaining both power output and work speed.
Solution Approach 2:
The controller continuously monitors operation signals from all operation devices and adjusts pump connections based on calculated demanded flow rates. This feedback ensures that pump reconnection occurs only when necessary for genuine operational needs, preventing unintentional decreases in work speed while maintaining required power levels.
3Adaptability or versatility
If the control lever enables operation of two actuators to increase versatility, then adaptability is improved, but composite operation causes sharp increase in actuator speed
Solution Approach 1:
The controller calculates demanded flow rates in advance based on operation signals and predetermined characteristics before actually switching pump connections. This preliminary calculation allows the system to prepare for composite operations smoothly, preventing sharp speed increases by gradually adjusting pump connections according to calculated requirements.
Solution Approach 2:
The system adjusts pump connection parameters gradually based on calculated demanded flow rates rather than abrupt switching. This controlled parameter change ensures smooth transitions during composite operations, preventing sharp increases in actuator speed while maintaining the ability to operate two actuators through one control lever.
Data Source
AI summary
To make it possible to prevent a decrease in work speed due to a decrease in the speed of a given actuator when an operator unintentionally performs a fine operation of the control lever of the other actuator in a state in which the given actuator is driven by the hydraulic fluid delivered from a plurality of pumps, a controller (41) sets, as a composite dead zone line serving as a boundary of a composite dead zone, a composite dead zone line such that as an operation amount in one direction of a control lever (12L) or (13L) of a control lever device (12) or (13) is increased, the width of the composite dead zone corresponding to an operation amount in the other direction of the control lever is widened, and corrects the operation amount in the other direction such that the demanded flow rate of an actuator increases from zero, when the control lever is operated in the other direction in a state in which the operation amount in the one direction of the control lever remains within a range of the composite dead zone, and the operation amount in the other direction exceeds the composite dead zone line.