Drivetrain Shift Mechanism With Biasing Assemblies

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Solution Overview

Problem

Current drivetrain assemblies with shift mechanisms are costly and complex to manufacture, and they face issues with undesirable shifting resistance and blocked shift conditions due to misalignment of gear teeth.

Innovation Solution

The drivetrain assembly incorporates a shift mechanism with two shift assemblies, each having a biasing member to bias the shift fork in a specific direction along the shift rail axis, and a return biasing member to facilitate movement and prevent damage during blocked shift conditions, along with a stationary shift rail and common design components for multiple assemblies to reduce complexity and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a shift mechanism with multiple shift assemblies is used, then torque distribution control is improved, but device complexity increases

Engineering Contradiction:
Improvetorque distribution controlVSAvoidshift mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The shift mechanism is divided into multiple independent shift assemblies (first shift assembly with first shift fork, second shift assembly with second shift fork), each capable of independently actuating different shift collars. This segmentation allows complex torque distribution control to be achieved through simpler, modular components rather than a single complex mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple shift assemblies share common design features including identical biasing members, return biasing members, and structural configurations. Each assembly can perform the same basic function of actuating a shift collar along the shift rail axis, but collectively they provide versatile torque distribution control across different drive modes.

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

2Ease of operation

If biasing members are added to each shift assembly, then shifting operation smoothness is improved, but manufacturing cost increases

Engineering Contradiction:
Improveshifting operation smoothnessVSAvoidmanufacturing cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The first biasing member and second biasing member are designed with identical structural features and functional characteristics. Each biasing member applies biasing force to its respective shift fork in the same manner, ensuring smooth shifting operations while allowing for standardized manufacturing processes and reduced production costs through component uniformity.

Inventive Principle:
Principle #33Homogeneity

3Reliability

If return biasing members are included, then protection against blocked shift conditions is improved, but device complexity increases

Engineering Contradiction:
Improveprotection against blocked shift conditionsVSAvoidshift mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The return biasing members are pre-installed in each shift assembly to provide protective force before blocked shift conditions occur. When a shift collar encounters misalignment or blocked conditions, the return biasing member immediately applies force to prevent damage, eliminating the need for complex protective mechanisms or post-failure intervention systems.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Ease of manufacture

If common design components are used across multiple assemblies, then manufacturing complexity is reduced, but adaptability decreases

Engineering Contradiction:
Improvemanufacturing complexityVSAvoidassembly configuration flexibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The shift mechanism is segmented into independent, modular shift assemblies that can be configured in different combinations. Each assembly uses common standardized components for manufacturing efficiency, but the modular nature allows flexible arrangement and configuration to meet different torque distribution requirements and drive mode specifications.

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 configuration reduces manufacturing complexity and costs while ensuring smooth shifting operations and preventing damage during misalignment issues, allowing for efficient torque distribution to vehicle traction wheels in various drive modes.

Implementation Method 1

The first shift assembly may have a first biasing member. The first biasing member may bias the first shift fork in a first direction along the shift rail axis. The second shift assembly may have a second biasing member. The second biasing member may bias the second shift fork in a second direction along the shift rail axis.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a return biasing member to facilitate movement and prevent damage during blocked shift conditions

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3480497B1Drivetrain assembly having a shift mechanism
Publication Date: 2021.08.18 ARVINMERITOR TECHNOLOGY LLC
  • EP3480497B1 patent drawingFigure 1
  • EP3480497B1 patent drawingFigure 2
  • EP3480497B1 patent drawingFigure 3

AI summary

A drivetrain assembly having a shift mechanism. The shift mechanism may include a shift rail, a first shift assembly, a second shift assembly, and a sector cam. The shift rail may be fixedly disposed on a housing. The sector cam may control movement of the first shift assembly and the second shift assembly.