Axle Assembly Preload Bolt for Bearing Deflection Control

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Solution Overview

Problem

Existing axle assemblies face challenges in maintaining consistent bearing preload, leading to reduced operational life and increased deflection due to settling and wear, particularly in applications where a stable preload force is necessary for efficient torque transmission and braking performance.

Innovation Solution

The proposed axle assembly incorporates a preload bolt system that applies a stable axial force to the roller bearings through a threaded connection with the planet carrier, allowing for axial flexibility and reducing the need for additional components like wheel end covers, while the sun gear positioning arrangement constrains axial movement to enhance lubricant flow and prevent overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If traditional bearing support structures are used, then the axle assembly requires additional components like wheel end covers and shims, but this increases device complexity and weight

Engineering Contradiction:
Improvenumber of componentsVSAvoidbearing preload consistency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent combines multiple functions into the brake housing: it serves as both the brake assembly housing and the bearing support structure. The brake housing directly supports the roller bearings and incorporates the sun gear positioning arrangement, eliminating the need for separate wheel end covers and shims while maintaining bearing preload consistency

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The brake housing is designed to perform multiple functions simultaneously: housing the brake assembly, supporting the roller bearings, positioning the sun gear, and maintaining bearing preload. This multi-functional design reduces the total component count while improving reliability

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

2Reliability

If bearing preload is not maintained consistently, then deflection increases and operational life reduces, but maintaining preload requires complex adjustment mechanisms

Engineering Contradiction:
Improvebearing preload consistencyVSAvoidpreload maintenance mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The brake housing is designed with built-in features that preliminarily establish and maintain bearing preload through its structural configuration. The sun gear positioning arrangement and bearing support geometry are pre-configured to maintain consistent preload without requiring additional adjustment mechanisms during operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The brake housing structure itself provides the bearing preload maintenance function through its rigid construction and integrated support features. The system is self-sufficient, using the brake housing's own structural integrity to maintain bearing preload consistency without external adjustment mechanisms

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3427989B1Axle assembly having a bearing preload bolt
Publication Date: 2021.06.23 ARVINMERITOR TECHNOLOGY LLC
  • EP3427989B1 patent drawingFigure 1
  • EP3427989B1 patent drawingFigure 2
  • EP3427989B1 patent drawingFigure 3

AI summary

An axle assembly having a preload bolt. The preload bolt may couple an output flange that may be supported by a roller bearing assembly to a planet carrier. A preload force may be exerted on the roller bearing assembly when the preload bolt is tightened to the planet carrier.