Coaxial Gear System Torque Distribution
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Solution Overview
Problem
Conventional gear systems face limitations in efficiently transferring torque from multiple power sources while providing a wide range of gear ratios, leading to suboptimal vehicle performance and increased complexity in mechanical systems.
Innovation Solution
A coaxial gear-train design incorporating multiple planetary gear-sets and intermediate shafts, supported by deep-groove and roller bearings, allows for asynchronous rotation and reduced friction, enabling a wide-node gear ratio spread and efficient torque distribution between an internal combustion engine and electric motor/generators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional gear systems are used to transfer torque from multiple power sources, then the system structure is simple, but the gear ratio spread is limited and torque distribution efficiency is reduced
Solution Approach 1:
The patent employs nested planetary gear sets where planetary gears are arranged in multiple stages with sun gears, planet gears, and ring gears nested within each other. This nesting configuration enables a wide gear ratio spread (3 to 1) while maintaining a compact structure that does not significantly increase overall system complexity
Solution Approach 2:
The patent transitions from conventional single-axis gear arrangements to a multi-dimensional coaxial configuration where multiple planetary gear sets share common rotation axes. This dimensional reorganization allows torque from multiple power sources to be distributed efficiently across different gear ratios simultaneously, achieving both wide ratio spread and manageable structural complexity
2Productivity
If multiple planetary gear-sets are used to achieve wide gear ratio spread, then torque distribution efficiency improves, but friction and mechanical losses increase
Solution Approach 1:
The patent introduces intermediate carriers and shafts as mediators between the planetary gear sets and the final output. These intermediaries facilitate smooth torque transfer and distribution across multiple power sources while minimizing direct frictional contact between gear components, thereby reducing mechanical losses
Solution Approach 2:
The patent employs dynamic torque distribution where the planetary gear sets can adaptively allocate torque from multiple power sources based on operating conditions. This dynamic operation optimizes the engagement and disengagement of gear components, reducing unnecessary friction and energy losses while maintaining high torque distribution efficiency
3Speed
If deep-groove and roller bearings are used to support the gear-train, then rotation smoothness and speed increase, but manufacturing complexity and cost increase
Solution Approach 1:
The patent employs deep-groove ball bearings and roller bearings that serve multiple functions: supporting radial loads, accommodating axial loads, and enabling high-speed rotation. These multi-functional bearings reduce the need for additional specialized components, thereby managing manufacturing complexity while achieving the desired rotation smoothness and speed
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 gear-train achieves a 3 to 1 gear ratio spread, allowing for efficient vehicle propulsion with reduced torque requirements from motor/generators, enabling a cost-effective, compact, and efficient hybrid powertrain suitable for front-wheel-drive applications.
Implementation Method 1
supported by deep-groove and roller bearings, supported with respect to the housing via at least one deep groove ball bearing and at least one roller bearing
Data Source
AI summary
A gear-train for transferring torque from multiple power sources includes first, second, and third input members, and an output member. The first and second input members rotate about a first axis, the third input member rotates about a second axis, and the output member rotates about a third axis. The gear-train additionally includes a first gear-set connected to the first input member. The gear-train also includes a second gear-set connected to the second input member. The gear-train additionally includes an intermediate shaft that rotates about a fourth axis. Furthermore, the gear-train includes a third gear-set connected to the intermediate shaft. In the third gear-set, first member is connected to the intermediate shaft and to the third input member, second and third members are set coaxially relative to the intermediate shaft and configured for asynchronous rotation with each other, and the third member is also connected to the output member.