Planetary Gear Differential with Equal Tooth Count
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Solution Overview
Problem
Existing powertrain differential systems are limited in their flexibility and efficiency for torque distribution between axially aligned drive wheels, as they are primarily designed for front and rear axle torque distribution rather than direct drive wheel torque management.
Innovation Solution
A differential planetary gear system with a ring gear, sun gear, and planetary gears, where the ring gear and sun gear toothing have the same number of teeth and module, allowing for even torque distribution and compact design, enabling the system to function as an axle differential for axially aligned drive wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional differential gears are used for torque distribution, then the system is proven reliable for front and rear axle torque distribution, but the system cannot efficiently distribute torque between axially aligned drive wheels of a single axle
Solution Approach 1:
The planetary gear system is designed to perform multiple functions: it can distribute torque between front and rear axles (as in traditional applications) and simultaneously distribute torque between axially aligned drive wheels of a single axle. This multi-functionality resolves the contradiction by making the system adaptable to different torque distribution requirements without requiring separate differential mechanisms for each application.
Solution Approach 2:
The planetary gear system is segmented into distinct components (ring gear, sun gear, planetary gears, carrier) that can independently receive and transmit torque to different outputs. This segmentation allows the system to provide multiple torque distribution paths simultaneously, enabling versatility while maintaining a unified structural framework that avoids excessive complexity.
2Adaptability or versatility
If conventional axle differentials are used for drive wheel torque distribution, then the torque distribution function is achieved, but the system occupies large space and has significant weight
Solution Approach 1:
The planetary gear system employs a nested configuration where planetary gears are arranged around a central sun gear, and the entire assembly is contained within a ring gear. This nesting allows multiple gear elements to occupy a compact radial space, significantly reducing the overall size and weight of the differential system compared to conventional axle differentials while maintaining the torque distribution function.
Solution Approach 2:
The invention transitions from the traditional linear/axial arrangement of conventional differentials to a radial/concentric arrangement in the planetary gear system. By organizing components in concentric circles around a central axis, the system achieves compactness in multiple dimensions simultaneously, reducing both the radial footprint and axial length, thereby decreasing overall weight and space occupation.
3Productivity
If the ring gear and sun gear have different numbers of teeth, then the system can provide varied torque distribution ratios, but the torque distribution between sun gear and ring gear becomes uneven
Solution Approach 1:
The patent applies different local qualities to different components: the ring gear and sun gear are designed with different numbers of teeth to achieve the desired overall torque distribution ratio between axle outputs, while the planetary gears are specifically designed with tooth counts that create equal transmission ratios in the local meshing zones. This local optimization ensures uniform torque distribution from each planetary gear to both sun and ring gears, maintaining stability and efficiency simultaneously.
Solution Approach 2:
The invention carefully selects and adjusts the tooth count parameters of different gear components to achieve the desired torque distribution characteristics. By changing the tooth count parameters of planetary gears specifically (while maintaining different tooth counts between ring and sun gears), the system achieves both varied overall torque distribution ratios and uniform local torque transmission, resolving the contradiction between productivity and stability.
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 allows for flexible torque distribution between drive wheels, reducing weight and size while enabling efficient power transfer to both drive wheels, enhancing the system's versatility and compactness compared to traditional axle differentials.
Implementation Method 1
planetary gears, which engage with the ring gear toothing on one side and with the sun gear toothing on the other side
Data Source
AI summary
A powertrain for a motor vehicle, with a differential planetary gear system, which has at least one ring gear with ring gear toothing, at least one sun gear with sun gear toothing, planetary gears which engage with the ring gear toothing on one side and with the sun gear toothing on the other side, and a planetary gear carrier, on which the planetary gears are rotatably mounted. The ring gear toothing and the sun gear toothing have the same number of respective gear wheel teeth.