Coaxial Worm Reduction Gear for Compact Self-Locking Shading Drives
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Solution Overview
Problem
Conventional mechanical reducers used in shading systems, such as roller shutters and awnings, are bulky and noisy due to their three-stage gear reduction design, requiring a powerful motor to overcome the magnetic brake's constant braking effect, which limits the system's compactness and efficiency, especially at slow speeds.
Innovation Solution
A mechanical reducer design incorporating a coaxial worm gear train with uniformly distributed first gears, bevel gears, and a fifth gear on the output shaft, eliminating the need for a magnetic brake by utilizing an irreversible gear train to prevent unintended rotation, allowing for a smaller, less powerful motor and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional three-stage gear reduction design is used, then the reduction function is achieved, but the mechanical reducer becomes bulky and noisy
Solution Approach 1:
The patent combines the brake function and reduction function into a single integrated mechanical reducer unit. The worm gear mechanism simultaneously provides both the reduction ratio and the self-locking brake effect, eliminating the need for separate magnetic brake components and reducing overall system size and noise.
Solution Approach 2:
The patent replaces the magnetic brake system with a mechanical worm gear self-locking mechanism. The worm gear's inherent friction and geometry provide automatic braking without electromagnetic components, reducing noise and simplifying the mechanical structure.
2Reliability
If a magnetic brake is permanently activated to prevent unintended rotation, then the brake function is achieved, but the motor requires greater power to overcome the braking effect
Solution Approach 1:
The worm gear mechanism is self-locking by design, automatically preventing reverse rotation without requiring external braking force. The geometry of the worm gear creates sufficient friction to hold the load in position, eliminating the need for a separately powered magnetic brake system.
Solution Approach 2:
The patent converts the inherent friction in the worm gear, which would normally be considered a loss, into a beneficial self-locking mechanism. This friction prevents unintended rotation and eliminates the need for additional braking power, actually reducing the total motor power requirement.
3Reliability
If a magnetic brake is used to block rotation, then the brake function is achieved, but the tubular motor requires a minimum length that prevents shorter installations
Solution Approach 1:
The brake function is merged into the reduction gear mechanism itself. The worm gear's self-locking property provides the braking function within the same compact housing as the reduction stages, eliminating the need for additional magnetic brake components and reducing the overall tubular motor length.
4Power
If a conventional three-stage gear reduction design is used, then the reduction function is achieved, but the mechanical reducer becomes bulky
Solution Approach 1:
The patent arranges the gear stages in a nested or compact configuration where components are positioned efficiently within the housing. The worm gear and subsequent gear stages are arranged to minimize the overall volume while maintaining the required reduction ratio.
Solution Approach 2:
The patent transitions from a linear arrangement of gear stages to a more three-dimensional compact layout. By utilizing spatial arrangement in multiple dimensions rather than a simple linear sequence, the reduction mechanism achieves the required ratio in a smaller overall volume.
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 design reduces the size and noise of the mechanical reducer, enabling a more compact shading system with a less powerful motor, improved start-up efficiency, and reduced electronic control issues at slow speeds, allowing for narrower and shorter installations.
Implementation Method 1
a worm mounted coaxially on the input shaft, and a gear train comprising: three first gears distributed uniformly around the worm screw, each meshing with the worm screw
Implementation Method 2
for each first gear, a second gear which is bevel and fixed coaxially to the first gear, for each second gear, a third gear which is bevel, which meshes with the second gear
Implementation Method 3
eliminating the need for a magnetic brake by utilizing an irreversible gear train to prevent unintended rotation
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention concerns a mechanical reduction gear (156) comprising: - an input shaft (158) rotated by a motor, - an output shaft (160) coaxial with the input shaft (158), - an endless screw (250) mounted coaxially on the input shaft (158), and - a gear train (200) comprising: - three first gears (252) uniformly distributed around the endless screw (250), each meshing with the endless screw (250) and moveably mounted to rotate about a first axis perpendicular to the axis of the endless screw (250), - for each first gear (252), a second conical gear (254) coaxially attached to the first gear (252), - for each second gear (254), a conical third gear (256), meshing with the second gear (254) and rotatable about a second axis of rotation parallel to the axis of rotation of the endless screw (250), - for each third gear (256), a fourth gear (258) coaxially attached to the third gear (256), and - a fifth gear (260) coaxially mounted on the output shaft (160) and which meshes with the or each fourth gear (258).