Actuator with Spring Brake for Screen Speed Control
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Solution Overview
Problem
Existing actuators for home-automation screens, such as rolling shutters and blinds, face challenges in variable-speed control of asynchronous motors, which require complex electronic control and can generate heat due to generator operation when used with brakes, and lack precise position sensing without complex designs.
Innovation Solution
An actuator combining a direct current electronic switching motor with a mechanical brake, specifically a spring brake, positioned between stages of the reduction gear, which dissipates energy generated by the load and provides precise speed regulation, eliminating generator operation and simplifying control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an asynchronous motor is used with variable-speed control, then speed regulation capability is improved, but device complexity increases due to complex electronic control requirements
Solution Approach 1:
The patent replaces complex electronic variable-speed control of asynchronous motors with a simpler mechanical brake system that provides continuous drag torque. This mechanical approach substitutes for the complex electronic control infrastructure, achieving speed regulation through mechanical means rather than complex electronic modulation.
Solution Approach 2:
The patent extracts the speed control function from the motor's electronic control system and implements it separately through a dedicated mechanical brake system. By separating the braking function into an independent mechanical component, the complexity of the main electronic control system is reduced.
2Use of energy by moving object
If an asynchronous motor operates as a generator during load descent, then energy recovery is possible, but heat dissipation issues arise
Solution Approach 1:
The patent converts the harmful effect of energy generation during load descent into a beneficial braking force. The mechanical brake system dissipates the energy that would otherwise cause heat problems in the motor, transforming a potential harm (heat dissipation issues) into a useful function (controlled descent through friction braking).
3Device complexity
If a plate brake is used with on/off mode, then braking function is simple, but motor operates as generator causing heat dissipation
Solution Approach 1:
The patent transitions from a static on/off brake control mode to a dynamic continuous control mode. The mechanical brake provides continuous drag torque that dynamically adjusts to the load conditions, preventing the motor from operating as a generator while maintaining simple mechanical control architecture.
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 results in a quiet, easy-to-control actuator that prevents generator operation, ensures precise position sensing, and maintains constant speed despite load variations, enhancing user experience and safety by integrating electronic speed control within the motor module.
Implementation Method 1
the brake is a mechanical brake having a continuous drag torque... to dissipate the energy generated by the load
Implementation Method 2
the brake is a spring brake comprising a helical spring which is mounted tightly in a drum
Data Source
AI summary
This actuator for driving a home-automation screen includes an electric motor (M), a reduction gear (R) for transmitting the movement of the motor to the home-automation screen and a brake. The actuator includes a direct current electronic switching motor (M) and a mechanical brake (2) having a continuous drag torque.