Inter-axle Differential Assembly with Selective Mode Connection

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Solution Overview

Problem

Conventional inter-axle differential assemblies in driving axle systems for motor vehicles are complex and lack a robust, space-efficient solution for selecting between open, locked, and disconnected modes, which affects torque distribution and wheel speed synchronization.

Innovation Solution

An inter-axle differential assembly with a connection means that allows selection between open, locked, and disconnected modes using a single mechanism, featuring a differential spider, pinions, and an output wheel that can rotate independently or together with the rear differential wheel, enabling different rotational speed settings for forward and rear driving axles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional inter-axle differential assembly with separate control devices for locking mechanism and disengagement assembly is used, then the system can provide open, locked, and disengaged modes, but the device complexity increases and robustness decreases

Engineering Contradiction:
Improvemode selection capabilityVSAvoidcontrol device quantity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the locking mechanism and disengagement assembly into a single integrated mechanism controlled by one control device. The control device selectively positions the output wheel relative to the rear differential wheel to achieve locked mode (engaged), open mode (disengaged), and disengaged mode (neutral), eliminating the need for separate control devices and reducing overall system complexity while maintaining full functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single control device performs multiple functions by selectively positioning the output wheel in different positions. It can lock the differential housing and output wheel to the rear differential wheel for locked mode, disengage the output wheel for open mode, and disengage both for disengaged mode, making one device universal for all three operational modes

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

2Adaptability or versatility

If multiple separate control devices are used for locking mechanism and disengagement assembly, then each function can be controlled independently, but the ease of operation decreases and system robustness is reduced

Engineering Contradiction:
Improveindependent control capabilityVSAvoidcontrol device operation
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent merges independent control of locking and disengagement functions into a single control device that selectively positions the output wheel. This unified approach simplifies operation while maintaining the ability to independently select between locked, open, and disengaged modes through single-device control

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If a conventional inter-axle differential assembly with separate locking mechanism and disengagement assembly is used, then the system can provide all required functions, but the space efficiency decreases

Engineering Contradiction:
Improvefunctional capabilityVSAvoidassembly space occupation
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent combines the locking mechanism and disengagement assembly into a single integrated structure where the output wheel can be selectively positioned. This merging eliminates redundant components and reduces the space occupied by the inter-axle differential assembly while preserving all required functions for locked, open, and disengaged modes

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The output wheel is positioned within the differential housing structure, nesting the disengagement function within the existing locking mechanism space. This nested arrangement allows the output wheel to be integrated into the compact differential assembly without requiring additional external space

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP3475114B1An inter-axle differential assembly, a driving axle assembly and a motor vehicle
Publication Date: 2021.07.21 SCANIA CV AB
  • EP3475114B1 patent drawingFigure 1~2
  • EP3475114B1 patent drawingFigure 3~4
  • EP3475114B1 patent drawingFigure 5a~5c

AI summary

An inter-axle differential assembly (8) for distribution of torque between two driving axles in a motor vehicle, comprising a driving input shaft (11), a forward differential wheel (12), a rear differential wheel (23), a differential spider (15) connected for common rotation with the input shaft and on which differential pinions (19) configured to meshingly engage with said differential wheels (12, 23) are rotatably mounted, and a differential housing (21) to which the differential spider is connected for common rotation. The assembly further comprises an output wheel (26) via which torque is transferable to a rear driving axle, and a connection means (30) movable between: - an open position in which it connects the output wheel to the rear differential wheel, and in which the differential housing can rotate independently of the rear differential wheel, - a locking position in which it connects both of the differential housing and the output wheel to the rear differential wheel, and - a disconnecting position in which it connects the differential housing to the rear differential wheel, and in which the output wheel can rotate independently of the rear differential wheel.