Transfer Case Differential Gear Torque Distribution

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Solution Overview

Problem

Conventional motor vehicles with rigid all-wheel drive systems experience power loss, increased tire wear, and fuel consumption due to speed differences between front and rear wheels, especially when cornering or driving on uneven terrain, leading to potential damage and inefficiencies in torque distribution.

Innovation Solution

A transfer case with a differential gear and differential lock that allows for adjustable torque distribution between axle shafts, featuring a switching device to connect or decouple gear wheels, enabling a compact design and adaptive torque management to prevent tension and optimize energy use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid all-wheel drive system is used, then torque can be transmitted to both front and rear axles, but power loss and fuel consumption increase due to speed differences between wheels

Engineering Contradiction:
Improvetorque transmission reliabilityVSAvoidpower loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies a differential mechanism that dynamically adjusts torque distribution between front and rear axles based on wheel speed differences. The differential gear allows the axles to rotate at different speeds while maintaining torque transmission, eliminating the rigid connection that causes power loss in conventional systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The differential mechanism changes the torque distribution parameter dynamically, allowing varying torque ratios between front and rear axles depending on driving conditions. This parameter adaptation resolves the contradiction by optimizing torque distribution rather than maintaining a fixed rigid connection.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a rigid all-wheel drive system is used, then traction is improved, but tire wear and fuel consumption increase

Engineering Contradiction:
ImprovetractionVSAvoidtire wear
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The differential mechanism dynamically adapts to wheel speed variations during cornering and different driving conditions, allowing wheels to rotate at different speeds without causing binding. This dynamic adjustment prevents excessive tire wear while maintaining effective traction.

Inventive Principle:
Principle #15Dynamics

3Loss of energy

If a differential mechanism is added to allow different wheel speeds, then power loss is reduced, but device complexity increases

Engineering Contradiction:
Improvepower lossVSAvoidtransfer case complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines the differential mechanism with the existing transfer case structure, integrating torque distribution functionality into the existing drivetrain architecture. This merging approach reduces overall system complexity compared to adding a separate differential system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The transfer case is designed to perform multiple functions: torque distribution to front and rear axles, differential action to accommodate wheel speed differences, and gear shifting. This multi-functionality eliminates the need for separate components, reducing overall system complexity.

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

4Volume of moving object

If the first axle shaft is guided through the hollow shaft, then installation space and weight are reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improveinstallation spaceVSAvoidshaft alignment precision
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The first axle shaft is guided through the hollow shaft, creating a nested configuration where one component passes through another. This nesting arrangement reduces the overall volume and installation space of the transfer case while maintaining functional requirements.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP3034348B1Distributor gear for dividing a torque to at least a first and a second axle shaft of a motor vehicle
Publication Date: 2019.06.05 NAF NEUNKIRCHENER ACHSENFABRIK
  • EP3034348B1 patent drawingFigure 1

AI summary

The invention relates to a distribution gearbox (10) for distributing a torque to at least one first and one second axle shaft (W3, W5) of a motor vehicle, in particular a self-propelled work machine.The transfer case (10) comprises at least one input shaft (W1) which can be coupled to an engine, in particular a hydraulic motor, of the motor vehicle, at least one first gear (Z4) which is rotaryally connected to the input shaft (W1) for transmitting a torque, a hollow shaft (W4) through which the first axle shaft (W3) passes, a differential gear (12) by means of which a torque can be distributed between the first axle shaft (W3), the hollow shaft (W4) and the second axle shaft (W5), and a differential lock (14) which can be switched between a locked state in which at least the first gear (Z4) is rotaryally connected to the first axle shaft (W3) and an open state in which at least the first gear (Z4) is rotaryly decoupled from the first axle shaft (W3).