Shift Collar Biasing Linkage for Blocked Axle Shifts

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Solution Overview

Problem

Existing shift mechanisms for axle assemblies face challenges in synchronizing the rotational speed of the shift collar with the drive pinion gears, leading to blocked shifts and inefficiencies, particularly when the shift collar is inhibited from moving along the axis.

Innovation Solution

A shift mechanism comprising an actuator, detent linkage, linkage, and biasing member, where the biasing member controls relative rotational movement between the detent linkage and the linkage, allowing the actuator shaft and detent linkage to rotate with respect to the linkage when the shift collar is inhibited, facilitating synchronization and preventing overheating by storing potential energy for release when conditions permit axial movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the shift collar is inhibited from moving along the axis, then synchronization with drive pinion gears is achieved, but the actuator shaft and detent linkage cannot rotate freely causing blocked shifts and energy wastage

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoidshift completion efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The biasing member transforms the rigid mechanical connection into a dynamic system where the detent linkage can rotate relative to the linkage when the shift collar is blocked. This allows the actuator to continue rotating while the biasing member absorbs the energy, preventing system failure and enabling shift completion once synchronization is achieved.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The biasing member changes the mechanical parameter of stiffness between the detent linkage and linkage, allowing controlled relative rotation when needed. This parameter change enables the system to adapt between rigid synchronization mode and flexible rotation mode, resolving the contradiction between reliability and productivity.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the actuator shaft and detent linkage are rigidly connected to the linkage, then structural simplicity is maintained, but overheating occurs when the shift collar is inhibited from moving

Engineering Contradiction:
Improvemechanical connection simplicityVSAvoidactuator temperature
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The biasing member acts as an intermediary element between the detent linkage and the linkage, providing a compliant connection that allows relative rotation. This intermediary prevents direct rigid coupling, enabling energy absorption through biasing member deformation and preventing actuator overheating while maintaining structural simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If the detent linkage is prevented from rotating relative to the linkage, then shift positioning accuracy is improved, but energy wastage occurs during blocked shift conditions

Engineering Contradiction:
Improveshift positioning accuracyVSAvoidactuator energy consumption
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The biasing member provides beforehand cushioning by being pre-loaded in a biased state, ready to absorb energy when the shift collar becomes blocked. This prior cushioning mechanism prevents energy wastage by allowing the actuator to continue rotating without fighting against a rigid constraint, while still maintaining accurate shift positioning through the controlled compliance of the biasing member.

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

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 solution ensures efficient synchronization of the shift collar with drive pinion gears, preventing overheating and energy wastage by allowing the actuator to complete shifts even during blocked conditions, thereby enhancing the operational efficiency and reliability of the axle assembly's shift mechanism.

Implementation Method 1

a biasing member that operatively connects the detent linkage to the linkage and that permits the actuator shaft and the detent linkage to rotate about the actuator axis with respect to the linkage when the shift collar is inhibited from moving along the axis

Methodology Applied
Scientific EffectElastic potential energy storage: Spring

Data Source

PatentEP4067703B1Axle assembly and shift mechanism for a shift collar
Publication Date: 2024.12.25 ARVINMERITOR TECHNOLOGY LLC
  • EP4067703B1 patent drawingFigure 1
  • EP4067703B1 patent drawingFigure 2
  • EP4067703B1 patent drawingFigure 3

AI summary

A shift mechanism having a biasing member that operatively connects a detent linkage to a linkage. The biasing member permits an actuator shaft of an actuator and the detent linkage to rotate about an actuator axis with respect to the linkage when a shift collar is inhibited from moving along the axis.