Planetary Torque Transfer for Compact Multi-Mode Axle Drive
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Solution Overview
Problem
Existing torque transfer devices in vehicles with multiple axles often separate torque splitting and range gear selection into different hardware components, leading to inefficiencies and increased complexity, particularly in heavy-duty vehicles.
Innovation Solution
A torque transfer device with a planetary gear system and shifting devices that integrates torque splitting and range gear selection, allowing for various drive modes, including four-wheel drive and two-wheel drive, through a compact design that enhances torque distribution and reduces friction losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If torque splitting and range gear selection are separated into different hardware components, then each component can be optimized independently, but the overall device complexity and number of parts increases
Solution Approach 1:
The patent combines torque splitting and range gear selection functions into a single integrated torque transfer device. The planetary gear system simultaneously performs both functions: it splits torque between drive axles while also providing low-range and high-range gear ratios through the interaction of sun gear, ring gear, and planet gears. This eliminates the need for separate torque transfer devices and range gear mechanisms, reducing overall part count while maintaining manufacturability.
Solution Approach 2:
The torque transfer device is designed as a multi-functional component that performs multiple operations within a single mechanism. The planetary gear system can operate in different modes (four-wheel drive, two-wheel drive, low-range, high-range) by selectively engaging different gear paths. This universal design allows one component to replace what would traditionally require multiple separate components, simplifying the overall drivetrain architecture.
2Ease of operation
If a traditional transmission with separate range gear is used, then gear ratio selection is straightforward, but the device occupies more space and increases in size
Solution Approach 1:
The planetary gear system employs a nested configuration where planet gears are positioned around and mesh with both the sun gear and ring gear in a compact arrangement. The sun gear, planet gears, and ring gear are concentrically arranged, allowing the entire gear train to fit within a small radial envelope. This nested structure enables multiple gear ratios to be achieved within a compact volume, eliminating the need for larger traditional range gear mechanisms.
3Ease of manufacture
If multiple separate components are used for torque transfer, then each component can be simpler in design, but friction losses increase due to more connection points
Solution Approach 1:
By merging torque splitting and range gear selection into a single planetary gear system, the patent reduces the number of connection points and interfaces where friction losses occur. The integrated design eliminates the need for additional couplings, bearings, and meshing surfaces that would exist if separate components were used. Although individual gear meshes experience friction, the overall reduction in connection points and components results in lower total friction losses.
4Volume of moving object
If a compact torque transfer device is designed, then space is saved, but the device complexity in achieving multiple drive modes increases
Solution Approach 1:
The planetary gear system employs dynamic configuration where the same physical components (sun gear, planet gears, ring gear) can be selectively engaged to provide different drive modes. By dynamically changing which gears are connected to which drive axles and whether the planet carrier or ring gear is locked, the system achieves multiple drive modes (four-wheel drive, two-wheel drive, low-range, high-range) without requiring additional physical components. This dynamic reconfiguration of existing elements provides mode versatility within a compact 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
The integrated torque transfer device provides improved torque distribution, increased traction, and reduced friction losses, enabling versatile drive modes suitable for different conditions, such as muddy terrain and cruising, while potentially replacing traditional range gears in transmissions.
Implementation Method 1
a planetary gear system comprising a sun gear, a ring gear, and a planet gear carrier carrying a plurality of planet gears
Data Source
Figure 1~2
Figure 3a~3c
Figure 4a~4c
AI summary
A torque transfer device (1) for distributing torque from an input shaft (2) to a first and a second output shaft (3; 4) driving a first and a second axle of a vehicle, respectively, comprising a planetary gear system (10, 410, 510, 610) and a first shifting device (20) selectively settable to one of a first position, a second position, and a third position, wherein: - in the first position, it provides increased output torque via the planetary gear system to the first and second output shafts, - in the second position, it provides increased output torque only to the first output shaft, and - in the third position, it provides output torque only to the first output shaft, at a direct gear ratio, or at a gear ratio which is lower than in the second position.