Air Disc Brake Actuation Shaft Layout for Wear Adjuster Space

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Solution Overview

Problem

Existing air disc brake systems face challenges in accommodating a manual adjuster shaft while maintaining effective transmission of the adjuster drive to the wear adjuster mechanism, particularly due to space constraints and the need for compact design.

Innovation Solution

The operating shaft features opposed arcuate surfaces with offset axes of rotation, incorporating a pin that extends at a non-zero angle to engage the wear adjuster mechanism, allowing sufficient space for the manual adjuster shaft and enhancing durability through separate hardening, with a part-spherical head and flattened regions to reduce wear and stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the manual adjuster shaft is co-axially arranged with the piston, then the brake can be lightweight and compact, but there is insufficient space to accommodate both the manual adjuster shaft and the adjuster mechanism

Engineering Contradiction:
Improvebrake compactnessVSAvoidspace accommodation
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The pin is arranged at a non-zero angle with respect to the axis of the piston and the manual adjuster shaft, creating a three-dimensional configuration that allows all components to coexist within the compact brake assembly. This angular arrangement utilizes spatial dimensions effectively to resolve the conflict between compactness and component accommodation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If the pin extends at a non-zero angle with respect to the axis of rotation, then sufficient space is created for the manual adjuster shaft, but the manufacturing complexity increases

Engineering Contradiction:
Improvespace for manual adjuster shaftVSAvoidpin arrangement
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The pin is provided as a separate component rather than being integrally formed with the operating shaft. This segmentation allows the pin to be manufactured separately with standard machining processes, then assembled into the operating shaft, thereby reducing overall manufacturing complexity while maintaining the beneficial non-zero angle configuration.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the pin is a separate component from the operating shaft, then the pin can be separately hardened to enhance durability, but the assembly complexity increases

Engineering Contradiction:
Improvepin durabilityVSAvoidcomponent assembly
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pin is pre-hardened through heat treatment before assembly into the operating shaft. This preliminary action enhances the pin's durability and wear resistance in advance, and the subsequent assembly is simplified through interference fit or press-fit methods that require standard machining operations rather than complex manufacturing processes.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3564552B1An actuation mechanism
Publication Date: 2021.06.02 MERITOR HEAVY VEHICLE BRAKING SYSTEMS (UK) LIMITED
  • EP3564552B1 patent drawingFigure 1
  • EP3564552B1 patent drawingFigure 2
  • EP3564552B1 patent drawingFigure 3~4

AI summary

An actuation mechanism for an air disc brake, comprising an operating shaft and a wear adjuster mechanism have an input driving portion, the operating shaft comprising opposed pairs of arcuate surfaces arranged with offset axes of rotation, one surface of each pair arranged to be grounded to a housing of the disc brake and the other surfaces of each pair arranged to transmit an actuating force to a brake pad of the disc brake upon rotation of the operating shaft; the operating shaft further comprising a recess intermediate the pairs of surfaces for accommodating a portion of the wear adjuster mechanism, wherein one of the operating shaft and the input driving portion further comprises a pin arranged to engage a corresponding slot of the other of the operating shaft or input driving portion, the pin extending at a non-zero angle with respect to both the axes of rotation and the direction of force transmission.