Hydraulic Drive Hysteresis Circuit Fast Stroke Control
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Solution Overview
Problem
Existing hydraulic drives for autarkic linear systems lack cost-effectiveness while ensuring reliable operation in both fast and load modes, with continuous switching between valve positions leading to inefficiencies and increased energy consumption.
Innovation Solution
Incorporation of a hysteresis circuit with automatically switching valves and a differential piston-cylinder unit, along with an equalizing reservoir, to prevent continuous switching and optimize valve operation, reducing the need for external power supplies and minimizing throttling losses, thereby enhancing system robustness and reducing size and energy requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a switching valve is used to change between fast stroke and load stroke modes, then the piston speed can be increased in fast stroke mode, but continuous toggling between switching positions occurs leading to instability and energy loss
Solution Approach 1:
The hysteresis circuit is designed with predetermined switching thresholds that create a dead zone, cushioning against continuous switching by preventing the valve from toggling when pressure fluctuates near the switching point. This ensures stable mode operation while maintaining the ability to switch between fast stroke and load stroke modes.
2Productivity
If various valves are used to compensate displacement volume imbalance, then fast stroke/load stroke characteristic can be achieved, but device complexity and cost increase
Solution Approach 1:
The hysteresis circuit integrates multiple control functions into a single circuit architecture, combining the displacement volume compensation and mode switching control in one unified system. This reduces the number of separate valves and control elements needed while maintaining the fast stroke/load stroke characteristics.
Solution Approach 2:
The hysteresis circuit serves multiple functions simultaneously: it controls the switching between fast stroke and load stroke modes, compensates for displacement volume imbalance, and provides stable pressure control. This multi-functionality reduces overall system complexity compared to using separate dedicated components for each function.
3Ease of manufacture
If pump capacity is reduced for cost savings, then system size and cost decrease, but ability to maintain high speed in fast stroke mode is compromised
Solution Approach 1:
The system dynamically switches between two operational modes: fast stroke mode where the differential cylinder uses the area difference for high speed with reduced pump capacity, and load stroke mode where the full pump capacity is utilized for force generation. This dynamic adaptation allows a smaller pump to achieve both high speed and adequate force output as needed.
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 ensures reliable operation in both fast and load modes with reduced energy consumption and physical size, achieving efficient and cost-effective hydraulic drive performance by preventing continuous switching and optimizing valve operation.
Implementation Method 1
a hysteresis circuit which prevents a continuous switching between switching positions of the load switching valve (16)
Implementation Method 2
hydraulic fluid flowing from the annular chamber via the switching valve and a fluid connection provided by the valve arrangement flows into the piston chamber of the differential cylinder
Data Source
AI summary
An autarkic hydraulic linear drive with a hydraulic arrangement and a method for operating the same. The hydraulic arrangement a pump unit, an equalizing reservoir, a load switching valve configured to switch between a fast extension and a load extension, and a hysteresis circuit. The hysteresis circuit is configured for triggering a first switching process of the load switching valve at a first control pressure and a second switching process of the load switching valve at a second control pressure that is different than the first control pressure.