Hydraulic Winch Control System for Fine Load Positioning
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Solution Overview
Problem
Conventional control systems for hydraulic winches lack fine control, particularly during lowering operations, and the use of counterbalance valves increases heat, necessitating additional flushing, while removing them leads to aggressive drum speed and load overshooting.
Innovation Solution
A winch assembly with a controller that separates brake control from drum rotation, releasing the brake at a first position displacement threshold and activating the pump at a second threshold, allowing for fine control of load position and eliminating the need for a counterbalance valve by modulating motor speed through a gear ratio command.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a counterbalance valve is used to control load position, then fine control of load position is achieved, but heat generation increases and flushing frequency increases
Solution Approach 1:
The patent removes the counterbalance valve from the hydraulic circuit and replaces it with a control system that uses a brake and pump coordination. This extraction eliminates the heat-generating valve while maintaining load position control capability through alternative means (brake control with pump timing).
Solution Approach 2:
The patent replaces the hydraulic valve-based control system with a mechanically-controlled brake system coordinated by an electronic controller. The controller manages brake engagement/disengagement and pump timing to achieve load position control without relying on the hydraulic counterbalance valve, thereby reducing heat generation.
2Temperature
If the counterbalance valve is removed, then heat generation is reduced, but drum speed becomes too aggressive and load overshoots desired position
Solution Approach 1:
The patent employs a controller that receives feedback from a position sensor monitoring the drum's position. This feedback loop allows the controller to adjust brake engagement timing and pump operation dynamically, preventing load overshoot while maintaining the eliminated counterbalance valve configuration. The real-time feedback ensures precise load position control without aggressive drum speed.
3Device complexity
If brake and pump operate simultaneously, then load control is simplified, but fine control of load position is lost
Solution Approach 1:
The patent segments the control functions by separating brake control from pump operation. The controller manages them as distinct, coordinated functions rather than simultaneous operations. The brake handles load holding and position control, while the pump provides hydraulic power only when needed, enabling fine load position control through sequential rather than simultaneous operation.
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
Enables precise control of load position with slow winch drum speeds, reduces heat generation in the hydraulic circuit, and minimizes flushing requirements, improving operational efficiency and precision.
Implementation Method 1
The drum is coupled to a hydraulic motor, which in turn is hydraulically coupled to a hydraulic pump. The hydraulic pump may be operatively coupled to an engine of the machine or other prime mover.
Implementation Method 2
A brake may also be provided that may normally engage and hold the drum in place, but may be disengaged to permit drum rotation.
Data Source
AI summary
A hydraulic winch assembly uses a control algorithm that separates brake control from drum rotation to permit fine control of load position. Actuation of an operator interface to a first position displacement threshold will release a drum brake but will not activate a hydraulic pump for operating a hydraulic motor coupled to the drum until the operator interface is moved to a second position displacement threshold. During the operating condition when the brake is released but the pump is not operating, the force of a load applied to a cable coupled to the drum may cause the cable to slowly unwind from and rotate the drum, thereby permitting fine control of drum rotation. Additionally, when the pump is activated upon further movement of the operator interface, a speed of the motor may be modulated, such as by a gear ratio command, to permit precise control over lower drum speeds.