Electric Winch Brake Timing Control via Torque Differential
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Solution Overview
Problem
Electric winch devices in cranes face challenges in preventing slipping-down and pull-up phenomena due to timing discrepancies between brake release and motor rotation initiation, which existing hydraulic-based technologies cannot effectively address.
Innovation Solution
An electric winch device with a controller that measures current values to derive torque differentials, controlling the brake to release or apply braking actions based on these differentials, ensuring synchronized motor rotation and brake operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the negative brake releases the braking action early to allow winch drum rotation, then the hoisting operation can start, but a slipping-down phenomenon occurs where the object drops momentarily
Solution Approach 1:
The controller initiates the release of the negative brake in advance before the motor fully starts rotation. By timing the brake release to occur just as the motor begins to rotate the winch drum, the system prevents the object from dropping while ensuring smooth transition to hoisting operation.
2Reliability
If the negative brake releases the braking action late to maintain object position, then position stability is maintained, but a pull-up effect occurs where the winch drum performs hoisting while braking is still applied
Solution Approach 1:
The controller monitors motor rotation status and releases the negative brake at the precise moment when motor rotation begins. This timing prevents excessive braking force from causing pull-up effects while maintaining object position stability during the transition phase.
3Reliability
If hydraulic pressure control is used to synchronize brake release with motor rotation, then slipping-down and pull-up phenomena are prevented, but the system complexity increases due to hydraulic components
Solution Approach 1:
The patent replaces the hydraulic pressure control system with an electric control system. The controller directly monitors motor rotation status and controls the negative brake release timing through electrical signals, eliminating the need for hydraulic pressure pumps, direction control valves, switching valves, and brake valves while achieving the same synchronization effect.
4Reliability
If a pressure sensor and counterbalance valve are added to control brake release timing, then slipping-down phenomenon is prevented, but the device complexity and cost increase
Solution Approach 1:
The patent eliminates the need for pressure sensors and counterbalance valves by using the controller to directly monitor motor rotation status through electrical parameters. The controller determines when to release the negative brake based on motor current and rotation feedback, replacing mechanical sensing and control components with an integrated electronic control system.
Data Source
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AI summary
Provided is an electric winch device including: an electric motor; a winch drum; a brake; an operation lever; an ammeter; and a controller. The controller includes: a first torque derivation unit which derives a value of a first torque applied to the winch drum due to a load of an object; a second torque derivation unit which derives a value of a second torque generated in the winch drum in the direction of rotation for hoisting the object by a drive torque of the electric motor, on the basis of a current value measured by the ammeter; and a brake control unit which determines a timing for releasing a braking action on the winch drum after the operation lever has been operated to a hoisting side or a lowering side, on the basis of a differential between the second torque value derived by the second torque derivation unit and the first torque value derived by the first torque derivation unit, and which causes the brake to release the braking action on the winch drum by transmitting, to the brake, a control signal instructing release of the braking action on the winch drum at the determined timing.