Pilot Hydraulic Valve Damping for Lift Oscillation Control
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Solution Overview
Problem
Hydraulic systems with hydraulically pilot-operated valves in lifting devices experience resonance phenomena and uncontrollable oscillations due to rapidly changing control inputs, particularly at higher temperatures, leading to operational interruptions and increased maintenance costs.
Innovation Solution
A hydraulic system incorporating a reducing element and a hydraulic pressure accumulator in the pilot line to control the switching position of the hydraulically pilot-operated valve, smoothing pressure changes and preventing sudden valve switching, thereby stabilizing the control behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a hydraulically pilot-operated valve is used to control hydraulic fluid supply, then the valve switching position can be changed by applying hydraulic fluid to a control input, but rapidly changing control inputs cause sudden pressure increases and drops leading to resonance phenomena and uncontrollable oscillations
Solution Approach 1:
A reducing element is introduced as an intermediary component in the pilot line between the control element and the hydraulically pilot-operated valve. This reducing element has a flow resistance that differs from conventional hydraulic lines, thereby mediating the pressure changes and preventing sudden pressure increases and drops that cause valve switching instability and resonance phenomena
Solution Approach 2:
The flow resistance parameter of the pilot line is changed by introducing a reducing element with specific flow resistance characteristics. This parameter change modifies the pressure transmission characteristics, smoothing out rapid pressure variations and preventing the resonance phenomena associated with sudden valve switching
2Stability of the object's composition
If vibration dampers are used for parts of the lifting device, then resonance phenomena can be reduced, but the dampers increase the loads on the lifting device's actuators by inhibiting mobility and their breakaway torque can also lead to resonance phenomena
Solution Approach 1:
The mechanical vibration damper system is replaced with a hydraulic control system modification. Instead of using mechanical dampers that physically resist motion, the invention modifies the hydraulic pilot control system to prevent resonance phenomena through controlled pressure management, thereby eliminating the need for mechanical dampers and their associated actuator loads
3Stability of the object's composition
If electronic detection and signal processing is used to prevent oscillation, then control signals can be processed electronically, but this increases device complexity and maintenance effort
Solution Approach 1:
The electronic control system is replaced with a hydraulic control solution. The reducing element in the pilot line provides passive hydraulic damping and pressure smoothing, eliminating the need for electronic sensors, processors, and actuators while achieving the same oscillation control objective through hydraulic means
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 system effectively reduces resonance and oscillations, ensuring stable operation over a wide temperature range with reduced maintenance efforts and costs.
Implementation Method 1
at least one hydraulic pressure accumulator is fluidly connected to at least one pilot line
Implementation Method 2
A reducing element can have a flow resistance for hydraulic fluid that differs from, and in particular is greater than, a conventional hydraulic line
Data Source
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AI summary
Hydraulic system for a hydraulic lifting device (1) comprising: - at least one hydraulically piloted valve (2) for controlling the supply of hydraulic fluid to at least one hydraulic consumer (11) of the hydraulic lifting device (1), and - at least one control element (4) for hydraulically piloting the valve (2), wherein the control element (4) is fluidly connected to the hydraulically piloted valve (2) via at least one pilot line (5, 6), and the switching position of the at least one hydraulically piloted valve (2) can be controlled via the at least one pilot line (5, 6) by supplying hydraulic fluid through the control element (4), wherein - in the at least one pilot line (5, 6) between the control element (4) and the at least one hydraulically piloted valve (2) there is at least one reducing element (7) effective in at least one direction, preferably in two directions.8) is arranged and - at least one hydraulic pressure accumulator (9, 10) is fluid-conductingly connected to at least one pilot line (5, 6).