Worm-Bevel Gear Layout for Compact Quiet Linear Actuators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing gear designs for linear actuators with crown and bevel wheels suffer from suboptimal power transmission and noise issues due to complex toothing, while maintaining a compact structure and high reduction ratio is challenging.
Innovation Solution
The bevel wheel is arranged perpendicular to the worm wheel axis with a gear train connection, using conic frustum-shaped bevel wheels and spur or helical gear wheels for improved tooth engagement, and integral manufacturing with plastic moulding tools to reduce costs and enhance power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a crown and bevel wheel gearing is used with the bevel wheel in extension of the worm wheel, then a compact structure with large reduction is achieved, but the toothing becomes complicated resulting in suboptimal power transmission and increased noise
Solution Approach 1:
The patent repositions the bevel wheel so its axis of rotation is perpendicular to the worm axis, rather than in extension of the worm wheel. This dimensional change allows the bevel wheel to be driven through a gear train (spur or helical gears) instead of direct meshing, simplifying the toothing geometry while maintaining compactness and improving power transmission efficiency.
2Reliability
If the bevel wheel is arranged perpendicular to the worm axis with a gear train connection, then power transmission and noise are improved, but the structural complexity increases
Solution Approach 1:
The patent introduces spur or helical gear wheels as intermediary elements between the worm wheel and the bevel wheel. These intermediate gears simplify the toothing geometry by using standard cylindrical gear profiles instead of complex bevel-crown meshing, while the gear train efficiently transmits power from the worm drive to the perpendicular bevel wheel axis.
3Ease of manufacture
If conventional toothing designs are used for crown and bevel wheels, then manufacturing is simplified, but noise and power transmission are compromised
Solution Approach 1:
By changing the spatial arrangement to have the bevel wheel axis perpendicular to the worm axis, the patent enables the use of standard spur or helical gear toothing profiles instead of complex crown-bevel meshing. This dimensional reconfiguration maintains ease of manufacture through conventional moulding tools while significantly reducing noise and improving power transmission through better tooth engagement.
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 achieves better power transmission, reduced noise, and maintains a compact structure, allowing for efficient force distribution and reduced material usage while simplifying manufacturing and assembly.
Implementation Method 1
the worm wheel is in drive connection with the bevel wheel through a gear train
Implementation Method 2
the bevel wheel is conic frustum shaped with its smallest diameter situated closest to the axis of rotation of the crown wheel and having its largest diameter closest to the circumference of the crown wheel
Data Source
AI summary
Gear, preferably for actuators of the type, where an electric motor (1) through the gear drives an activation element, such as a pivotal arm or a longitudinally movable element, and where the gear has at least two gearing stages. The first stage is constituted by a worm drive with a worm—(11; 13a, 13b) and the subsequent gearing stage is constituted by a crown and bevel wheel (23; 16a, 16b). The crown wheel faces towards the worm drive and has a power take-off (24, 27) in extension of or in all essentials in extension of the worm (11) or parallel thereto. The bevel wheel (16a, 16b) is with its axis of rotation arranged perpendicular in relation to the axis of rotation of the worm (11), and the worm wheel (13a, 13b) is in drive connection with the bevel wheel (16a, 16b) through a gear train (14a, 15a; 14b; 15b). Thus a relatively compact transmission with a high gearing is achieved, and by having worm wheels, toothed gearing and bevel and crown wheels of plastic the transmission is in addition silent. A good tooth mesh between bevel wheel and crown wheel is particularly important. The gear may be used in a linear actuator which again may be used in a height adjustable table leg.