Brushless Door Drive with Magnetic Encoder for Compact Installation
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Solution Overview
Problem
Conventional door drives for automatic sliding and elevator doors are bulky, noisy, and costly due to the use of DC motors with gears, which lead to rapid wear and tear, and require significant installation space, making them unsuitable for compact and cost-effective solutions.
Innovation Solution
A compact door drive design utilizing a brushless electric motor with a magnetic absolute encoder for motor commutation and position control, eliminating the need for gears and reducing mechanical parts, noise, and wear, while providing high-resolution angle sensing for precise speed control and torque development without harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If DC motors with gears are used, then driving force can be generated, but noise increases and wear accelerates
Solution Approach 1:
The patent replaces the mechanical gear system with a direct drive configuration where the motor shaft directly connects to the belt drive mechanism. This eliminates gears entirely, substituting the mechanical transmission system with a simpler direct coupling that reduces noise and wear while maintaining the required driving force for door operation.
Solution Approach 2:
The patent extracts and removes the gear components from the drive system. By taking out the gears and their associated meshing mechanisms, the design eliminates the source of noise and wear while preserving the essential function of transmitting rotational motion to the belt drive.
2Power
If DC motors with gears are used, then driving force can be generated, but the number of moving mechanical parts increases
Solution Approach 1:
The patent replaces the complex mechanical gear transmission system with a direct drive configuration. This substitution eliminates multiple moving mechanical parts (gears, gear shafts, bearings) while maintaining the capability to generate and transmit the necessary driving force through a simpler direct coupling mechanism.
Solution Approach 2:
The patent extracts and removes the gear components from the drive system. By taking out the gears and their associated mechanical elements, the design reduces the number of moving parts from multiple components to essentially a direct connection between motor shaft and belt drive, simplifying the mechanical system.
3Power
If conventional DC motors are used, then driving force can be generated, but installation space increases
Solution Approach 1:
The patent replaces the conventional DC motor with a brushless motor design that integrates the commutation function electronically. This substitution eliminates the need for commutators and brushes, reducing the motor's overall dimensions and allowing for more compact installation within the door drive assembly.
Solution Approach 2:
The patent employs a brushless motor design where the control unit performs multiple functions including commutation, position sensing, and speed control. This multi-functionality integrates several subsystems into a single compact unit, reducing the overall installation space required compared to conventional separate components.
4Area of stationary object
If brushless motor with magnetic absolute encoder is used, then installation space is reduced, but cost increases
Solution Approach 1:
The patent employs a brushless motor design where the control unit performs multiple functions including commutation, position sensing, and speed control. This multi-functionality integrates several subsystems into a single compact unit, reducing the overall installation space required compared to conventional separate components.
Solution Approach 2:
The patent merges the angle sensor functionality directly into the motor assembly, combining the motor and sensor into an integrated unit. This merging eliminates the need for separate sensor mounting and wiring, reducing installation space while the cost is offset by the elimination of additional components and simplification of the overall system.
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 compact, quiet, and cost-effective door drive with immediate rotor position availability, high temporal resolution at low speeds, and smooth operation, allowing for integration within limited spaces like door jambs or lintels without the need for additional installation space or synchronization, thus enhancing the overall efficiency and reliability of door control systems.
Implementation Method 1
the angle sensor works according to a magnetic principle, is designed as an absolute value sensor
Implementation Method 2
an electronically commutated and/or brushless electric motor
Data Source
Figure 1~3
Figure 4~5
AI summary
The drive has a brushless direct current motor (10) e.g. permanently-excited synchronous motor, generating drive power, and a belt drivewheel (12) controlling a tough toothed belt (16) that transmits the power to the door panels (2, 3). An actuation device controls the motor, and comprises a digital magnetic absolute value sensor for generating an angular signal proportional to an angle of rotation of the motor. A commutation circuit commutates the motor, to which the signal from the sensor is fed, where the signal from the sensor is fed to a door position controller as an input variable.