Construction Machine Cylinder Pressure Control
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Solution Overview
Problem
Existing hydraulic systems for construction machines require additional valves for load holding during the extension and retraction of cylinders, which complicates the control system and increases complexity.
Innovation Solution
A controller with an integrated control system that analyzes pump pressure, bore side pressure, and rod side pressure to determine when to extend or retract the cylinder, eliminating the need for additional valves by using a master spool and pilot control valves to manage fluid flow based on operator input positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional valves are used for load holding during cylinder extension and retraction, then load holding capability is improved, but device complexity increases
Solution Approach 1:
The patent combines the load holding function with the existing directional control valves (master spool and pilot control valves) that are already present in the hydraulic system. The controller integrates pressure monitoring and command execution into a unified control system, eliminating the need for separate load holding valves while maintaining the required functionality through coordinated control of the existing valve components.
2Manufacturing precision
If additional valves are added to the hydraulic system, then control precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors bore side chamber pressure and pump pressure, and compares actual cylinder position (derived from operator input position) with desired position. This closed-loop feedback enables precise cylinder position control while maintaining simple operation, as the controller automatically adjusts valve commands based on pressure conditions without requiring complex manual intervention from the operator.
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
Enables efficient load holding and movement control of the cylinder without additional valves, simplifying the hydraulic system and reducing complexity while ensuring proper fluid management and pressure conditions for extension and retraction.
Implementation Method 1
A pump pressure sensor is located in the pump line and is used to detect pump pressure
Implementation Method 2
A bore side pressure sensor is located in the bore line upstream of the master spool and is used to detect bore side pressure
Implementation Method 3
A bore side chamber of the work cylinder is configured to be supplied with fluid from the pump during rod extension while fluid is removed from a rod side chamber
Data Source
AI summary
A construction machine including a pump, a pressure sensor measuring a pressure, and a work cylinder including a rod operable to extend and retract. The work cylinder has a bore chamber, a rod chamber, a bore chamber pressure sensor, a bore pressure, a rod chamber pressure sensor, and a rod pressure. The machine includes an input moveable between neutral, extension, and retraction positions, and a sensor to measure the position. The machine includes a controller programmed with an algorithm to control movement of the work cylinder on the basis of the detected position of the operator input. The algorithm is configured to confirm that the pump pressure exceeds the bore side chamber pressure as a prerequisite to setting a command that controls movement of the work cylinder for rod extension, in response to identification of the operator input in the rod extension position.