Disc Brake Adjusting Spindle Thread Limitation Against Over-Rotation

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Solution Overview

Problem

Disc brake adjusting spindles can become misaligned due to wear, leading to increased lever travel and delayed braking, and may fall out of adjustment units, resulting in a sudden loss of adjustment function.

Innovation Solution

A thread limitation is implemented on the adjusting spindle to restrict rotational movement, preventing it from falling out of the adjustment unit, using the same material composition as the spindle to minimize premature fatigue and allowing for fine adjustment without additional components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the adjusting spindle is allowed to rotate freely to adjust brake pad clearance, then the adjustment function is maintained, but the spindle may rotate too far and fall out of the adjustment unit, causing loss of adjustment function

Engineering Contradiction:
Improveadjustment functionVSAvoidadjustment function retention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A limiting feature is provided on the adjusting spindle that prevents it from rotating more than a predetermined amount. This preliminary constraint stops the spindle before it can fall out of the adjustment unit, thereby preventing the loss of adjustment function while still allowing normal adjustment operations to proceed

Inventive Principle:
Principle #9Preliminary anti-action

2Reliability

If a limiting feature is added to the adjusting spindle to prevent over-rotation, then the reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveadjustment function retentionVSAvoidspindle structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The limiting feature is integrated directly into the adjusting spindle as part of its structure, rather than being a separate component. This merging of functions maintains reliability improvement while minimizing the increase in device complexity, as the limiter becomes an inherent part of the spindle assembly

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the limiting feature is made from the same material as the adjusting spindle, then manufacturing is simplified, but the limiter may experience premature material fatigue

Engineering Contradiction:
Improvematerial compositionVSAvoidlimiter service life
Core Design Contradiction:
Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The limiting feature is designed with localized structural characteristics that differ from the main spindle body, such as modified geometry or stress distribution features. This allows the same material to be used throughout (simplifying manufacturing) while the local structural design compensates for potential fatigue issues by distributing stresses more effectively

Inventive Principle:
Principle #3Local quality

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

The thread limitation effectively prevents the adjusting spindle from unscrewing further, maintaining the adjustment function and ensuring proper brake operation by limiting rotational movement without additional components, thus enhancing brake performance and longevity.

Implementation Method 1

a threaded ring (5) located in the adjusting spindle (10), in combination with a disc spring (21a), secures the adjusting spindle (10) against unintentional adjustment or return movements

Methodology Applied
Scientific EffectThread engagement: Screw

Data Source

PatentEP4013974B1Disc brake with adjusting spindle
Publication Date: 2023.07.12 ZF CV SYST EURO BV
  • EP4013974B1 patent drawingFigure 1~2
  • EP4013974B1 patent drawingFigure 3~3a
  • EP4013974B1 patent drawingFigure 4~5

AI summary

The invention relates to a disk brake having an adjusting spindle (10), in particular the invention relates to a disk brake for motor vehicles, having an adjusting spindle (10) and an adjustment unit (20), wherein the adjusting spindle (10) has a boundary (12).