Transfer Case Mode Shifting via Reversible Motor

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Solution Overview

Problem

Current transfer cases for vehicles lack an efficient mechanism for seamless shifting between two-wheel drive and four-wheel drive modes, particularly in electronic shift on the fly systems, which can be complex and require manual intervention, limiting dynamic control and efficiency.

Innovation Solution

A transfer case design incorporating a dual drive gear system with a reversible electric motor, a range shifter, and a mode shifter, where the dual drive gear rotates to actuate both the range shifter and mode shifter, allowing for automatic or manual selection between two-wheel drive and four-wheel drive modes, utilizing a gear train and synchronizer for efficient torque distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a manual shifting mechanism is used in traditional transfer cases, then the structure is simpler, but the dynamic control and efficiency are limited

Engineering Contradiction:

Improveautomatic mode selectionVSAvoidshifting mechanism complexity

Core Design Contradiction:

Extent of automationVSDevice complexity

Solution Approach 1:

The dual drive gear serves multiple functions: it acts as both a range shifter (high-range/low-range/neutral) and a mode shifter (two-wheel drive/four-wheel drive) component. By integrating both shifting functions into a single gear that rotates in different directions, the patent reduces the number of separate mechanisms needed while achieving automated control through the electric motor.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces traditional manual mechanical shifting mechanisms with an electric motor-driven system. The reversible electric motor automatically controls the dual drive gear rotation, eliminating the need for manual intervention and enabling dynamic, on-the-fly mode changes without complex mechanical linkages.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If separate mechanisms are used for range shifting and mode shifting, then each function is more specialized, but the overall device complexity increases

Engineering Contradiction:

Improvenumber of shifting componentsVSAvoiddrive mode selection capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent merges the range shifter and mode shifter into a single dual drive gear component. This gear integrates both high-range/low-range shifting and two-wheel drive/four-wheel drive mode selection functions, reducing the total number of separate shifting mechanisms while maintaining full adaptability across all drive modes through a unified structure.

Inventive Principle:

Principle #5Merging (Combining)

3Extent of automation

If a reversible electric motor is used to drive the gear train, then automatic shifting is enabled, but the energy consumption increases

Engineering Contradiction:

Improveautomatic shifting capabilityVSAvoidelectric motor energy consumption

Core Design Contradiction:

Extent of automationVSUse of energy by moving object

Solution Approach 1:

The reversible electric motor operates periodically only when mode changes are required, rather than continuously. The motor activates to rotate the dual drive gear during shifting events (from two-wheel to four-wheel drive or vice versa) and remains inactive during steady-state operation, thereby enabling automatic shifting capability while minimizing overall energy consumption.

Inventive Principle:

Principle #19Periodic action

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

Enables seamless and efficient shifting between drive modes, enhancing vehicle dynamics and driver control, with automatic mode selection capabilities, improving torque distribution and reducing mechanical complexity.

Implementation Method 1

a reversible electric motor which drives the gear train wherein direction of the rotation of the electric motor determines engagement or disengagement of the mode shifter

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

a range shifter comprising a first cam, a first shift fork, wherein the first shift fork is driven axially by the first cam, and a first sleeve which is axially driven by the first shift fork; a mode shifter comprising a second cam, a second shift fork, wherein the second shift fork is driven axially by the second cam

Methodology Applied

Scientific EffectCam mechanism: Cam

Data Source

PatentUS9463691B1Electronic shift on the fly part-time electro mechanical transfer case

Publication Date: 2016.10.11 BORGWARNER INC

AI summary

A number of variations may include a transfer case comprising an input shaft and a first output shaft sharing a primary axis of rotation; a second output shaft offset from the first output shaft; a range shifter comprising a first cam constructed and arranged to selectively shift a vehicle to a high-range drive mode, a low range drive mode, or a neutral drive mode; a mode shifter comprising a second cam constructed and arranged to actuate a synchronizer which selectively shifts the vehicle between a two-wheel drive mode and a four-wheel drive mode a gear train having a first axis offset from the primary axis, and a reversible electric motor which drives the gear train wherein direction of the rotation of the electric motor determines engagement or disengagement of the mode shifter to selectively shift the vehicle between the two-wheel drive mode and the four-wheel drive mode.