Stepped Planetary Gear Torque Amplification

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Solution Overview

Problem

Existing drive train systems for motor vehicles are complex and occupy significant axial space due to their construction, particularly in the amplifying mechanism which uses multiple planetary gears, making them inefficient in terms of structural complexity and space usage.

Innovation Solution

The drive train is simplified by using stepped planets with larger and smaller planetary stages for torque amplification, coupled directly to the differential's input element, allowing for amplification factors of 10 to 20 and enabling a more compact design by eliminating the need for three planetary gears, and integrating the amplification mechanism with the differential carrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If three planetary gears are used in the amplifying mechanism, then torque amplification is achieved, but structural complexity and axial space increase

Engineering Contradiction:
Improvetorque amplificationVSAvoidstructural complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent combines the functions of three separate planetary gears into a single integrated planetary gear set with stepped planets. The stepped planets have different diameter stages that perform the torque amplification function previously requiring multiple separate gear sets, thereby merging multiple components into one unified structure that reduces complexity while maintaining the torque amplification capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The planetary gear stages are nested within each other in a compact arrangement. The stepped planets are configured with concentric stages of different diameters, allowing one gear stage to be positioned within or adjacent to another, creating a nested structure that achieves high torque amplification in a compact form factor with reduced axial space.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Power

If three planetary gears are used in the amplifying mechanism, then torque amplification is achieved, but axial installation space increases

Engineering Contradiction:
Improvetorque amplificationVSAvoidaxial space
Core Design Contradiction:
PowerVSLength of stationary object

Solution Approach 1:

The patent transitions from a linear arrangement of three separate planetary gears along the axial direction to a compact radial arrangement using stepped planets with concentric stages. By utilizing the radial dimension and creating gear stages with different diameters that share the same axial space, the design achieves high torque amplification without proportionally increasing axial length.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The planetary gear stages are nested within each other in a compact arrangement. The stepped planets are configured with concentric stages of different diameters, allowing one gear stage to be positioned within or adjacent to another, creating a nested structure that achieves high torque amplification in a compact form factor with reduced axial space.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Length of stationary object

If a compact amplifying mechanism is used, then axial space is reduced, but torque amplification capability may be compromised

Engineering Contradiction:
Improveaxial spaceVSAvoidtorque amplification
Core Design Contradiction:
Length of stationary objectVSPower

Solution Approach 1:

The stepped planets are designed with non-uniform local characteristics - different diameter stages positioned at different locations on the same planet carrier. This allows each local region of the planetary gear to perform a specific function in the torque transmission chain, enabling high overall torque amplification while maintaining a compact overall structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Each stepped planet performs multiple functions simultaneously - different diameter stages of the same planet engage with different gear elements to provide multiple gear ratios in sequence. This multi-functionality allows a single compact planetary stage to achieve the torque amplification effect that previously required three separate planetary gear sets.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 reduces structural complexity and axial space requirements, allowing for variable torque distribution while maintaining speed ratios, and enables the expansion of conventional drive trains to support adaptive torque application with a smaller torque application unit.

Implementation Method 1

the boosting mechanism comprises a coaxially arranged planetary gear set with a first boosting sun and a boosting web supporting a set of boosting planets meshing with the first boosting sun

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

the first boosting sun meshing with the planetary stages with a larger diameter

Methodology Applied
Scientific EffectGear: Gear

Data Source

PatentEP2826653B1Power transmission for a motor vehicle
Publication Date: 2016.12.14 VOLKSWAGEN AG
  • EP2826653B1 patent drawingFigure 1~2
  • EP2826653B1 patent drawingFigure 3~6

AI summary

The invention relates to a drive train for a motor vehicle, comprising: - a first electric machine (12) with a rotor (18) and a stator (16) for driving a driven axle (24) having two steering knuckles (20, 22) and passing coaxially through the rotor (18); - a transmission stage (26) coupled to the rotor (18) and arranged coaxially with the first electric machine (12); - a differential (32) coupled at its input element (34) to an output element (30) of the transmission stage (26), arranged coaxially with the transmission stage (26), and coupled at its output elements (36, 38) to the steering knuckles (22, 22); - a torque impingement unit (46, 62) coupled to the differential (32) via a reinforcement mechanism (44) and arranged coaxially with it, wherein the reinforcement mechanism (44) is a coaxially arranged planetary gear set. with a first amplification sun (52) and an amplification bridge (48),The invention comprises a set of amplification planets (50) mounted on which the first amplification sun (52) combs with the moment imprinting unit (46, 52). The invention is characterized in that the amplification planets of the amplification mechanism (44) are designed as step planets (50) with one planetary step of larger diameter (501) and one planetary step of smaller diameter (502), wherein the first amplification sun (52) combs with the planetary steps of larger diameter (501).