Differential Cylinder Hydraulic Circuit for Smooth Direction Switching
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Solution Overview
Problem
Existing hydraulic circuits for differential cylinders with suspended loads are complex, require multiple components, and experience pressure surges when actuation direction is switched, leading to increased space requirements and control complexity.
Innovation Solution
A simplified hydraulic circuit using a bidirectional pressure medium source with a reversible motor generator and directional control valves, allowing for efficient actuation direction switching and volume flow management through check valves, reducing component usage and control effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrically operated switching valves are used to control actuation direction, then reliable direction switching is achieved, but device complexity and component usage increase
Solution Approach 1:
The patent removes electrically operated switching valves from the hydraulic circuit, extracting the complex control component while maintaining reliable direction switching through a simplified mechanical arrangement using a bidirectional pump and check valves.
Solution Approach 2:
The hydraulic circuit is designed to automatically manage actuation direction changes using the bidirectional pump's inherent capability to reverse flow direction and check valves that automatically control pressure differential flow, eliminating the need for external electrical switching control.
2Ease of operation
If electrically operated switching valves are used for direction control, then precise actuation control is achieved, but control effort and space requirements increase
Solution Approach 1:
The patent combines the direction control function and flow management into a single integrated hydraulic circuit using a bidirectional pump, merging multiple functions into one component to reduce overall system footprint while maintaining ease of operation.
Solution Approach 2:
The bidirectional pump serves multiple functions: it controls actuation direction, manages volume flow differences between piston surfaces, and enables both lifting and lowering operations, making it a universal component that replaces multiple specialized components.
3Reliability
If electrically operated switching valves are used, then reliable pressure medium switching is achieved, but pressure surges occur during direction switching
Solution Approach 1:
The check valves are pre-positioned in the hydraulic circuit to automatically manage pressure differentials before switching occurs. The bidirectional pump is designed to gradually reverse rotation, preliminarily preparing the pressure medium for direction change and preventing sudden pressure surges.
Solution Approach 2:
The patent uses a bidirectional pump with variable speed capability that can dynamically adjust its rotation speed during direction switching, enabling smooth transition of pressure medium flow and eliminating rigid on/off switching that causes pressure surges.
4Adaptability or versatility
If variable displacement pumps or multiple pumps are used, then flexible flow control is achieved, but device complexity increases
Solution Approach 1:
A single bidirectional pump with variable speed capability performs the work of multiple pumps or complex variable displacement systems, providing flow control flexibility through speed variation while maintaining simple single-pump architecture.
Solution Approach 2:
The patent controls volume flow by changing the rotational speed parameter of the bidirectional pump rather than using complex displacement mechanisms, achieving flexible flow control through a simple parameter change that reduces mechanical complexity.
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 enables reduced component usage, simplified control, and efficient actuation direction switching, allowing for stepless actuation direction changes and effective load movement control, while utilizing a constant pump and variable-speed servo motor for high rapid traverse and pressing speeds.
Implementation Method 1
a first check valve through which a small quantity of pressure medium, resulting from a difference in the volume flows, can be drawn from a pressure medium reservoir into the piston crown space in order to enable at least a downward movement of the load caused by its weight
Implementation Method 2
The first check valve can be unlocked by means of a first pressure present in the first working line such that, during an upward movement of the load, an excess quantity of the pressure medium, caused by the difference in volume flows, can be discharged from the piston crown chamber into the pressure medium sink via the check valve
Implementation Method 3
simply by changing the flow direction of the pressure medium source, the pressure medium in the piston crown chamber or the annular chamber can be compressed or decompressed
Data Source
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AI summary
Disclosed is a hydraulic circuit for supplying pressure medium to a differential cylinder, via which a suspended load can be moved, with a bidirectional pressure medium source, via which an annular space of the differential cylinder can be supplied with a first volume flow via a first working line of the hydraulic circuit, and via which a piston head space of the differential cylinder can be supplied with a second volume flow via a second working line of the hydraulic circuit, the first volume flow being smaller than the second volume flow. The hydraulic circuit also contains a first check valve, via which a reduced quantity of pressure medium caused by a difference in the volume flows can be sucked in from a pressure medium sink into the piston head space in order to enable the load to move downwards due to the weight of the load. The first check valve can be unlocked via a first pressure present in the first working line in such a way that when the load moves upwards, an excess quantity of pressure medium caused by the difference in the volume flows can be discharged via the first check valve from the piston head chamber into the pressure medium sink.