Brake Adjuster Mechanism Wear Reduction via Periodic Clutch Action

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Solution Overview

Problem

Existing brake adjuster mechanisms suffer from excessive wear due to the constant engagement of torque limiting clutches during brake applications, leading to increased backlash and undesirable running clearance in brake assemblies, especially in heavy vehicles.

Innovation Solution

A brake adjuster mechanism incorporating a one-way clutch and torque limiting clutch with a friction device and biased projection system, where the ball bearings sit on lands between recesses, reducing the torque required for adjustment and minimizing wear by allowing the ball to remain on the land during brake release, thus lowering the torque applied to the adjuster components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the torque limiting clutch is engaged during every brake application to adjust for wear, then the brake compensation function is achieved, but excessive wear occurs on the adjuster components

Engineering Contradiction:
Improvebrake compensation functionVSAvoidservice life of adjuster components
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The adjuster mechanism is designed to operate periodically rather than continuously. The projection engages recesses only during specific brake applications when wear compensation is needed, rather than during every brake application. This periodic engagement significantly reduces the cumulative wear on adjuster components while maintaining the necessary brake compensation function.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The torque limiting clutch mechanism is extracted from continuous operation and activated only when necessary. The biased projection system allows the clutch to disengage from recesses during normal brake applications, separating the wear-inducing torque transmission from routine brake operations and retaining it only for wear compensation events.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If the adjuster mechanism is designed with predetermined backlash to accommodate running clearance, then proper brake pad clearance is maintained, but increased backlash results from component wear

Engineering Contradiction:
Improverunning clearanceVSAvoidbacklash control
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The adjuster mechanism automatically compensates for wear-induced backlash through periodic activation. As components wear and backlash increases, the mechanism self-adjusts by engaging the torque limiting clutch during subsequent brake applications, progressively reducing the excessive backlash back to the predetermined acceptable range without external intervention.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The biased projection system provides mechanical feedback that detects when wear compensation is needed. The projection's engagement and disengagement from recesses creates a self-regulating system that responds to changes in backlash, automatically initiating adjustment when wear exceeds acceptable limits and maintaining optimal clearance over time.

Inventive Principle:
Principle #23Feedback

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 design significantly reduces wear on the adjuster components by ensuring the ball remains on the land during brake release, resulting in lower torque application and reduced wear on every second brake operation, thereby extending the mechanism's lifespan.

Implementation Method 1

said input element being frictionally coupled by a friction device to said output element to resist rotation of the input element relative to the output element

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the pocket includes a resilient means for selectively biasing said projection into said first recess and said second recess

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2505868B1A brake adjuster mechanism
Publication Date: 2020.05.27 MERITOR HEAVY VEHICLE BRAKING SYSTEMS (UK) LIMITED
  • EP2505868B1 patent drawingFigure 1
  • EP2505868B1 patent drawingFigure 2
  • EP2505868B1 patent drawingFigure 3

AI summary

A brake adjuster mechanism including: an input shaft (18), a one-way clutch (36), and a torque limiting clutch (38), the input shaft being coupled to an input element (28) of the torque limiting clutch, the one-way clutch being coupled to the torque limiting clutch, the torque limiting clutch further including an output element (34) and a coupling portion, the coupling portion including a projection for selectively rotationally coupling said input element and said output element, one of said input element and output element including a first recess circumferentially spaced from a second recess, said projection being selectively biased into said first recess and said second recess, said input element being frictionally coupled by a friction device (27) to said output element to resist rotation of the input element relative to the output element.