Two-Stage Actuator Gear Layout for High Ratio in Low Height
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing actuators with low-voltage DC motors and two-stage reduction mechanisms are costly and require significant space, particularly in the overall height, due to the complexity of achieving a high transmission ratio in a single step.
Innovation Solution
A two-stage reduction mechanism is implemented, where the first stage uses a worm and intermediate gear wheel, and the second stage employs a spiral pinion in a parallel transmission with a spiral gear wheel, allowing for a compact design and reduced material usage, with the spiral pinion cooperating with a support for increased stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a two-stage reduction mechanism with worm and worm wheel is used, then the transmission ratio is achieved, but the overall height and space requirement increase
Solution Approach 1:
The patent transitions from a traditional vertical stacking arrangement of gear stages to a horizontal layout where the first and second gear stages are arranged side-by-side. This dimensional reconfiguration allows the intermediate gear wheel to extend with partial overlap along the output gear wheel, significantly reducing the overall height while maintaining the required transmission ratio of 1:1200 through the two-stage reduction mechanism.
Solution Approach 2:
The intermediate gear wheel is positioned to extend with partial overlap along the output gear wheel, creating a nested spatial arrangement. This nesting principle allows the first stage driven gear wheel to be partially contained within the spatial envelope of the second stage driven element, thereby reducing the overall height of the reduction mechanism to substantially equal to at most twice the thickness of the DC motor.
2Power
If a traditional worm and worm wheel transmission is used in both stages, then the transmission ratio is achieved, but the material cost and manufacturing cost increase
Solution Approach 1:
The patent applies different transmission mechanisms to different stages based on local requirements: the first stage uses a worm and worm wheel configuration suitable for high reduction ratio and self-locking, while the second stage uses a spiral pinion and spiral gear wheel configuration optimized for efficiency and cost-effectiveness. This localized optimization reduces material costs and manufacturing complexity while achieving the overall transmission ratio.
Solution Approach 2:
The patent changes the transmission mechanism parameters from uniform worm wheel transmissions to a hybrid configuration with spiral gearing in the second stage. This parameter change increases transmission efficiency considerably with respect to two worm wheel transmissions, allowing a lighter and hence lower-cost DC motor to suffice while maintaining the same moment supply.
3Length of stationary object
If the motor shaft is disposed transverse to the output shaft to save height, then the overall height is reduced, but the structural complexity increases
Solution Approach 1:
The patent segments the reduction mechanism into two distinct stages with clearly defined functional boundaries: the first stage handles the primary reduction from motor shaft to intermediate shaft, while the second stage handles the final reduction to the output shaft. This segmentation, combined with the transverse arrangement, manages structural complexity by creating modular, functionally-separated components that are easier to manufacture and assemble.
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 configuration results in a more cost-effective and compact actuator with a reduced overall height, enabling a lighter and more efficient motor, while maintaining the required transmission ratio, thus saving on material and manufacturing costs.
Implementation Method 1
a first stage with a worm carried on the motor shaft of the DC motor, which worm in a right-angle transmission cooperates with the circumference of an intermediate gear wheel
Implementation Method 2
a second stage with the spiral pinion which in a parallel transmission cooperates with the circumference of the output spiral gear wheel
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Actuator provided with a low voltage DC motor which is coupled via a two-stage reduction mechanism with an output gear wheel, wherein the reduction mechanism comprises a first stage with a worm carried on the motor shaft of the DC motor, which worm in a right-angle transmission cooperates with the circumference of an intermediate gear wheel, which intermediate gear wheel is carried on an intermediate shaft which carries along its axis a spiral pinion, and wherein the reduction mechanism furthermore comprises a second stage with the spiral pinion which in a parallel transmission cooperates with the circumference of the output gear wheel, which is implemented as a spiral gear wheel.