Slewing Hydraulic Control Valve for Unintended Speed Suppression
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Solution Overview
Problem
In slewing-type working machines, simultaneously conducting slewing and exchangeable operations can result in increased upper slewing body speed against the operator's intention, making it difficult to prioritize slewing motion effectively, especially when using exchangeable devices with low working pressures.
Innovation Solution
A slewing-type working machine with a variable displacement hydraulic pump, slewing motor, exchangeable actuator, and an exchangeable control valve system that detects operation amounts and reduces the opening degree of the exchangeable control valve when specific conditions are met, such as the slewing operation exceeding a reference amount and the exchangeable operation being detected, to prioritize slewing motion and prevent unintended speed increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the supply flow rate of hydraulic fluid to the slewing motor is increased to give priority to slewing motion, then slewing motion can be reliably started, but the upper slewing body might have an increased speed against operator's intention
Solution Approach 1:
The control valve opening degree is dynamically adjusted based on real-time detection of slewing operation amount and exchangeable operation status. The opening degree changes from a fixed state to a variable state that adapts to different operational conditions, allowing the system to provide priority flow to the slewing motor when needed while preventing unintended speed increases during other operations.
Solution Approach 2:
The control section continuously detects the operation amount of the slewing operation member and the operation status of exchangeable operation members, then uses this feedback information to adjust the opening degree of the exchangeable control valve. This closed-loop feedback mechanism ensures that the hydraulic flow distribution responds accurately to operator intentions and system conditions.
2Device complexity
If a common hydraulic pump is used for both slewing motor and exchangeable actuator, then system complexity is reduced, but hydraulic fluid distribution control becomes difficult during combined operation
Solution Approach 1:
The control valve serves as an intermediary device between the common hydraulic pump and the two actuators (slewing motor and exchangeable actuator). By adjusting the opening degree of this control valve, the system can regulate the flow rate of hydraulic fluid supplied to the exchangeable actuator, thereby indirectly controlling the flow available to the sleving motor. This intermediary mechanism enables precise flow distribution control while maintaining a relatively simple common pump architecture.
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
This solution allows for reliable prioritization of slewing motion while suppressing unintended speed increases of the upper slewing body, ensuring smooth operation and efficient use of hydraulic fluid, particularly when using exchangeable devices with low working pressures.
Implementation Method 1
a variable displacement hydraulic pump which discharges hydraulic fluid; a slewing motor which receives supply of the hydraulic fluid discharged from the hydraulic pump to operate
Implementation Method 2
an exchangeable control valve interposed between the hydraulic pump and the exchangeable actuator and configured to open and close so as to change a flow rate of the hydraulic fluid supplied from the hydraulic pump to the exchangeable actuator
Data Source
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AI summary
An opening and closing motion control section (71) controls an optional control valve (50) so as to reduce opening degree of the optional control valve (50) in a case where a first opening reduction condition is satisfied that a slewing operation detection section (91) detects an operation amount equal to or more than a reference operation amount (SV) set in advance so that the reference operation amount is larger than a minimum operation amount of a slewing operation member (81A) for causing slewing motion of an upper slewing body (2) and that an optional operation detection section (92) detects operation received by an optional operation member (82A).