Helical Planetary Gear Differential for Torque Biasing
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Solution Overview
Problem
Existing gear units for vehicle powertrains face challenges in achieving improved traction and driving behavior while minimizing component weight and complexity, as they often require separate assemblies for torque conversion, distribution, and locking effects.
Innovation Solution
A gear unit with an integral differential featuring a first and second planetary gearset, where the gearset elements have helical toothing generating torque-dependent axial forces, allowing for independent connection of output shafts without direct-driving teeth, enabling torque distribution and locking effects within a single assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate assemblies are used for torque conversion, distribution, and locking effects, then each function can be optimized independently, but the overall device complexity and component weight increase
Solution Approach 1:
The patent combines torque conversion, torque distribution, and locking effect functions into a single integrated differential assembly. The planetary gearset simultaneously performs torque conversion (through gear ratio), torque distribution (to multiple output shafts), and provides locking effects (through friction elements), eliminating the need for separate assemblies for each function.
Solution Approach 2:
The differential assembly is designed as a multi-functional component that performs multiple tasks: it converts torque from the input shaft, distributes torque to multiple output shafts in defined ratios, and provides torque-dependent locking effects. This universal design reduces the overall number of components while maintaining functional optimization.
2Reliability
If separate assemblies are used for torque conversion, distribution, and locking effects, then each function can be optimized independently, but the component weight increases
Solution Approach 1:
The patent merges multiple functional assemblies into a single lightweight differential unit. By integrating torque conversion gears, distribution mechanisms, and locking elements into one compact assembly, the total weight is reduced compared to having separate heavy assemblies for each function.
Solution Approach 2:
The differential employs a nested arrangement where planetary gears, friction elements, and connection means are arranged concentrically and interlocked. The planetary gears are positioned around a central input shaft, with friction elements nested within the gear structure, creating a compact, weight-efficient design.
3Productivity
If direct-driving teeth are used to connect output shafts, then torque transmission is direct and efficient, but the design flexibility and compactness are reduced
Solution Approach 1:
The patent introduces friction elements as intermediary components between the planetary gears and output shafts. These friction elements provide torque-dependent connection without requiring direct mechanical tooth engagement, allowing for more flexible and compact design while maintaining efficient torque transmission through friction-based force transfer.
Solution Approach 2:
The patent changes the connection mechanism from rigid mechanical tooth engagement to friction-based connection. This parameter change allows the output shafts to be connected in a more compact arrangement, improving design flexibility and enabling the differential to achieve a more compact form factor while maintaining torque transmission efficiency.
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 enhances traction and driving behavior by reducing component weight and complexity, achieving torque conversion and distribution with a self-locking function analogous to limited-slip differentials, while maintaining a compact and efficient design.
Implementation Method 1
The gearset elements have a helical toothing which generates an engagement force dependent on an applied torque, this axial force acting on connection means
Implementation Method 2
arranged and formed to at least indirectly connect the first output shaft and second output shaft... such that a torque is transmittable between the two output shafts
Data Source
AI summary
A gear unit includes an input shaft, output shafts and a differential having two planetary gearsets with a plurality of gearset elements. A first gearset element is connected to the input shaft, a second gearset element is connected to the first output shaft, and a third gearset element is connected to a gearset element of the second planetary gearset. A second gearset element of the second planetary gearset is connected to a housing, and a third gearset element of the second planetary gearset is connected to the second output shaft. A first output torque transmittable to the first output shaft. The gearset elements of the first planetary gearset and second planetary gearset have a helical toothing such that a torque is transmittable between the two output shafts.