Pass-Through Differential Without Stub Bearing for Higher Torque

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Solution Overview

Problem

Conventional pass-through differentials in 6×6 vehicle conversions face limitations in strength and durability due to the presence of a stub bearing, which restricts the size of pinion and output shafts, making them costly and sensitive to misalignment.

Innovation Solution

The solution involves eliminating the stub bearing, increasing the size of the output shaft and pinion bearings by 300%, and using a double row ball bearing for additional support, allowing for a larger pinion and output shaft configuration, such as a 1.3125-inch diameter/31-spline setup, and upgrading the threaded connection from ¾ inch to ⅞ inch, enabling enhanced strength and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a stub bearing is used in the conventional pass-through differential design, then the differential structure is compact, but the pinion and output shaft sizes are restricted, reducing strength and durability

Engineering Contradiction:

Improvepinion and output shaft strengthVSAvoiddifferential structure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The stub bearing is completely removed from the differential assembly. This extraction eliminates the space constraint that limited pinion and output shaft sizes, allowing for larger, stronger components while maintaining structural integrity through alternative bearing arrangements at the input and output shafts

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The design transitions from a compact single-plane arrangement to a distributed three-dimensional configuration where bearings are positioned at multiple locations along the shafts. This spatial redistribution allows larger component dimensions without increasing overall footprint proportionally

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Strength

If the pinion and output shaft sizes are increased for high torque applications, then strength and durability improve, but manufacturing cost and sensitivity to misalignment increase

Engineering Contradiction:

Improvetorque support capabilityVSAvoidalignment precision requirement

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The bearing configuration parameters are changed from a single stub bearing to multiple bearings distributed along the shafts. This parameter change increases the system's tolerance to misalignment while supporting larger pinion and output shaft dimensions for high torque applications

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Multiple bearings are strategically positioned to provide preemptive support and cushioning against potential misalignment issues. This beforehand cushioning reduces sensitivity to alignment variations that would otherwise be problematic with larger components

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If component sizes are increased to meet high horsepower requirements, then strength improves, but other components must be resized or modified

Engineering Contradiction:

Improvecomponent strength for high horsepowerVSAvoidcomponent configuration complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The input shaft and output shaft are designed as multi-functional universal components that can accommodate various pinion sizes and configurations. This universality allows the shafts to serve multiple functions while maintaining compatibility with different component sizes, reducing the need for custom modifications

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The differential is divided into modular segments with standardized interfaces. This segmentation allows individual components to be optimized for strength while maintaining compatibility with the overall system, enabling high horsepower applications without requiring complete redesign of all components

Inventive Principle:

Principle #1Segmentation

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 design enhances the strength and durability of the front tandem differential, allowing for increased torque support and improved manufacturing robustness, making it suitable for high-stress applications like 6×6 vehicles without the alignment and cost issues of traditional designs.

Implementation Method 1

one or more pinion bearings disposed on the input shaft and configured to support the input shaft and the pinion

Methodology Applied

Scientific EffectBall bearing: Ball Bearing

Implementation Method 2

an output bearing disposed around the output shaft and within the output boss

Methodology Applied

Scientific EffectBall bearing: Ball Bearing

Implementation Method 3

a seal configured to seal an outermost opening of the output boss

Methodology Applied

Scientific EffectSealing:

Data Source

PatentUS11525501B1Pass through differential

Publication Date: 2022.12.13 GERSTNER STEVEN R

AI summary

Pass-through differentials are described.