Hydraulic Assistance Device Pressure Control
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Solution Overview
Problem
Existing hydraulic assistance systems for slave machines, connected to master machines via a hitch or frame, face inefficiencies in displacement management due to unforeseen pressure variations in supply lines, leading to disturbances in the control of master/slave machine pairs, particularly when operating in all four quadrants.
Innovation Solution
A hydraulic assistance device with a variable displacement pump and double-acting cylinder, featuring two electrically adjustable pressure limiters on each supply line, allowing simultaneous pressure control of both chambers, and a calculation unit to manage these limiters based on sensor data to maintain optimal pressure balance and torque control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pressure relief valve is used to control pump displacement, then the system structure is simple, but displacement tracking precision deteriorates when pressure variations occur in supply lines
Solution Approach 1:
The single pressure relief valve is segmented into two separate pressure relief valves, each controlling one chamber of the double-acting cylinder. This segmentation allows independent pressure control for each chamber, enabling precise tracking of pressure variations in both supply lines simultaneously, thereby resolving the contradiction between structural simplicity and displacement tracking precision.
Solution Approach 2:
Two pressure relief valves act as intermediaries between the supply lines and the double-acting cylinder chambers. Each valve mediates the pressure transmission from its respective supply line to the corresponding chamber, allowing the system to accurately reflect pressure variations in both supply lines while maintaining a relatively simple overall structure.
2Ease of operation
If pump displacement is not precisely controlled, then the system operation is simple, but master/slave control stability deteriorates
Solution Approach 1:
The system implements feedback control by using pressure relief valves that automatically adjust chamber pressures based on supply line pressure variations. This passive feedback mechanism maintains precise pump displacement control without adding complex active control systems, thereby preserving operational simplicity while enhancing master/slave control stability.
Solution Approach 2:
The pressure relief valves provide self-service pressure regulation by automatically responding to pressure variations in the supply lines. This self-regulating mechanism ensures precise displacement control and stable master/slave operation without requiring external intervention or complex control algorithms, maintaining ease of operation while improving reliability.
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 ensures precise control of the slave machine's displacement and torque, adapting to varying conditions and maintaining stable operation across all quadrants, even with unforeseen pressure changes, thereby enhancing the efficiency and reliability of the master/slave machine coupling.
Implementation Method 1
two electrically adjustable pressure relief valves (90a, 90b) arranged respectively on the two control lines (80a, 80b), in order to control the pressure in the control chambers (12a, 12b)
Implementation Method 2
a double-acting cylinder defining two control chambers, to steer the pump's displacement in one direction or the other
Data Source
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AI summary
The invention relates to a hydraulic assistance device comprising: - a hydraulic machine (30) capable of driving a wheel (W) of the craft; - a variable displacement pump (10) comprising a double-acting actuator (12) defining two control chambers (12a, 12b) for hydraulically controlling the capacity of said pump (10); - two supply lines (40a, 40b) that connect the hydraulic machine (30) and the variable displacement pump (30) in order to form a closed circuit, characterised in that the device further comprises: - two control lines (80a, 80b), each being respectively drawn from one of the two supply lines (40a, 40b) and being configured to respectively supply one of the two control chambers (12a, 12b); - two electrically calibratable pressure limiters (90a, 90b) respectively disposed on the two control lines (80a, 80b).