Axle Differential Brake Assembly for Independent Pinion Braking

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Solution Overview

Problem

Existing axle assemblies with differential brakes lack an efficient mechanism to independently apply brake torque to inhibit rotation of the differential assembly and drive pinion, especially when the primary brake actuator is inoperative, leading to potential vehicle movement without intended braking.

Innovation Solution

The axle assembly incorporates a differential brake system with a rotatable braking component and friction member that can engage with a friction surface to apply brake torque to both the differential assembly and drive pinion, allowing for independent braking functionality, even when the primary brake actuator is off or inactive.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a differential brake system is added to independently brake the differential assembly and drive pinion, then braking reliability and safety are improved, but device complexity increases

Engineering Contradiction:
Improvebraking reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The differential brake assembly integrates the brake caliper, brake pads, and rotatable braking component into a single unit that combines with the existing differential assembly. The brake carrier is formed as part of the differential assembly housing, merging structural support and braking functions into one integrated component, thereby improving reliability without proportionally increasing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotatable braking component serves multiple functions: it acts as both a brake rotor for the differential brake system and a structural element that transmits braking torque to the drive pinion. This multi-functional design allows one component to perform several roles, improving braking reliability while minimizing the increase in device complexity.

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

2Reliability

If the differential brake uses a rotatable braking component connected to the drive pinion, then braking effectiveness is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvebraking effectivenessVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The differential brake assembly is segmented into distinct functional modules: the brake carrier formed as part of the differential assembly, the rotatable braking component as a separate but integrated element, and the brake caliper with brake pads as an independent actuating mechanism. This segmentation allows each component to be manufactured separately using standard processes, then assembled together, improving braking effectiveness while maintaining ease of manufacture.

Inventive Principle:
Principle #1Segmentation

3Ease of repair

If the differential brake is disposed outside the housing assembly, then ease of maintenance is improved, but device complexity increases

Engineering Contradiction:
Improveease of maintenanceVSAvoiddevice complexity
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The brake caliper and brake pads are extracted as separate serviceable components from the differential brake assembly, allowing them to be removed, inspected, and replaced independently without disassembling the entire differential unit. This extraction of wear-prone components improves ease of maintenance while the overall device complexity remains managed through the integrated brake carrier design.

Inventive Principle:
Principle #2Taking out (Extraction)

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 enables effective braking and parking brake functionality without relying on the primary brake actuator, reducing energy consumption and preventing vehicle movement when the torque source is inactive, thus enhancing safety and efficiency.

Implementation Method 1

A rotatable braking component may be rotatable with the connecting shaft. The rotatable braking component may have a friction surface. The differential brake may have a friction member. The friction member may be engageable with the friction surface to provide the brake torque.

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4257850A1Axle assembly having a differential brake
Publication Date: 2023.10.11 ARVINMERITOR TECHNOLOGY LLC
  • EP4257850A1 patent drawingFigure 1
  • EP4257850A1 patent drawingFigure 2
  • EP4257850A1 patent drawingFigure 3

AI summary

An axle assembly having a differential assembly, a drive pinion, and a differential brake. The differential assembly may be rotatable about a differential axis. The drive pinion may mesh with a ring gear of the differential assembly. The differential brake may be operable to apply a brake torque to inhibit rotation of the differential assembly.