Double Differential Bevel Reducer for High-Ratio Low-Sliding Transmission
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Solution Overview
Problem
Existing high reduction transmissions are bulky, inefficient, and prone to surface damage due to high relative sliding velocities, especially at high input speeds, and require complex designs with multiple shafts and bearings, making them unsuitable for compact applications like vehicle and helicopter drives.
Innovation Solution
A double differential reducer transmission with a symmetric arrangement of eight bevel gears, including a first and second planet gear set, and a double differential mechanism that reduces output speed through two rotational components, allowing high reduction ratios without significant size increase, using bevel gears to minimize sliding velocities and axial forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If bevel worm gear drives are used to achieve high reduction ratios, then the reduction ratio is improved, but the relative sliding velocity increases causing surface damage and premature failure
Solution Approach 1:
The transmission is divided into multiple stages with different gear types. The first stage uses a bevel worm gear for high reduction ratio, while subsequent stages use cylindrical gears for lower sliding velocity operation. This segmentation allows each stage to operate within optimal velocity limits while achieving cumulative high reduction.
Solution Approach 2:
The patent transitions from a single-stage worm gear approach to a multi-stage transmission system that adds temporal dimension to the reduction process. By distributing the reduction across multiple stages over time, the sliding velocity at each interface is reduced while maintaining overall high reduction capability.
2Loss of time
If multi stage transmissions with cylindrical gears are used to achieve high reduction ratios, then the reduction ratio is improved, but the device complexity increases with multiple shafts and bearings
Solution Approach 1:
The patent combines multiple gear stages into a integrated transmission assembly where shafts and bearings are shared between stages. The cylindrical gear stages are merged with the worm gear stage in a compact arrangement, reducing the total number of discrete components while maintaining multi-stage reduction functionality.
3Loss of time
If pericyclic transmissions with nutating bevel gears are used to achieve high reductions, then the reduction ratio is improved, but the axial mass forces and bearing loads increase significantly
Solution Approach 1:
The transmission is divided into multiple stages with different gear types. The first stage uses a bevel worm gear for high reduction ratio, while subsequent stages use cylindrical gears for lower sliding velocity operation. This segmentation allows each stage to operate within optimal velocity limits while achieving cumulative high reduction.
4Power
If high input speeds are used to increase power output, then the power is improved, but the relative sliding velocity increases causing efficiency reduction and surface damage
Solution Approach 1:
The transmission is divided into multiple stages with different gear types. The first stage uses a bevel worm gear for high reduction ratio, while subsequent stages use cylindrical gears for lower sliding velocity operation. This segmentation allows each stage to operate within optimal velocity limits while achieving cumulative high reduction.
Solution Approach 2:
The patent changes the gear type parameter across different stages. By transitioning from worm gear to cylindrical gear, the sliding velocity parameter is fundamentally altered at each stage, allowing high power transmission at low sliding velocities in the cylindrical gear stages while maintaining high reduction capability.
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 double differential transmission achieves high reduction ratios with low relative sliding velocities, improved efficiency, and compact design, reducing friction and heat generation, and enables energy storage and optimal motor efficiency in various driving conditions.
Implementation Method 1
a first outer side gear being a bevel gear and being connected to and drivable by the first input
Implementation Method 2
The double differential transmission achieves high reduction ratios with low relative sliding velocities
Implementation Method 3
reducing friction and heat generation
Data Source
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AI summary
A transmission having a housing (18), at least a first input (20) rotatable about a first input axis (IA1), and at least a first output (26) rotatable about a first output axis (OA1). The transmission further includes a first outer side gear (14) connected to and drivable by the first input, a first planet gear set comprising a first inner planet gear (11) and a first outer planet gear (15) with the inner and outer planet gears being rigidly connected to, and in axial alignment with, one another. The first planet gear set is rotatable (22, 24) via the first outer side gear and is also rotatable (23) about the first output axis. The transmission further includes a second outer side gear (16) in mesh with the first outer planet gear, and a second inner side gear (12) connected to the first output and being rotatable about the first output axis via the first inner planet gear.