Disc Brake Adjuster Ring for Wrap Spring Clearance Control

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Solution Overview

Problem

Existing disc brake adjustment devices experience increased clearance between brake pads and the brake disc due to wear, leading to longer reaction times and reduced braking forces, as the existing support mechanisms for wrap springs do not effectively compensate for the gap between the guide sleeve and the wrap spring.

Innovation Solution

The introduction of an intermediate ring that overcomes the play between the guide sleeve and the wrap spring, featuring a U-shaped elevation and beads to support the wrap spring, preventing axial and circumferential movement, and a stop to prevent rotation, thereby reducing the clearance and enhancing braking performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the wrap spring is supported directly on the guide sleeve, then the structure is simple, but the clearance between brake pads and brake disc increases due to play between components

Engineering Contradiction:
Improvestructure simplicityVSAvoidreaction time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

An intermediate ring is introduced between the guide sleeve and the wrap spring to eliminate play and prevent axial displacement. This intermediary component mediates the interaction between the guide sleeve and wrap spring, ensuring direct force transmission without clearance, thereby reducing reaction time while maintaining structural simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the wrap spring is supported on a washer on the side facing away from the rotary lever, then axial displacement is avoided, but the clearance between brake pads and brake disc increases

Engineering Contradiction:
Improveaxial displacement preventionVSAvoidreaction time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The intermediate ring serves as a mediator that combines the functions of axial displacement prevention with play elimination. It is positioned on the guide sleeve and provides a support surface for the wrap spring, ensuring both axial stability and direct force transmission without clearance, thus reducing reaction time.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If two wrap springs are arranged inside a sleeve and supported axially on the sleeve, then the structure is stable, but the play between sleeve and wrap spring cannot be compensated

Engineering Contradiction:
Improvestructural stabilityVSAvoidclearance compensation
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The intermediate ring acts as a precision intermediary component that eliminates play between the guide sleeve and wrap spring. By providing a precisely fitted support surface, it compensates for manufacturing tolerances and ensures minimal clearance, thereby improving the precision of the adjustment device while maintaining structural stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Stability of the object's composition

If the wrap spring is positioned with a distance or gap from the guide sleeve, then the wrap spring is axially fixed, but the reaction time of the disc brake increases

Engineering Contradiction:
Improveaxial fixationVSAvoidreaction time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The intermediate ring provides axial fixation for the wrap spring while eliminating the gap between the wrap spring and guide sleeve. By serving as a direct support interface, it ensures the wrap spring is axially positioned without clearance, enabling immediate force transmission and reducing reaction time.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reduces the reaction time of the brake pads to contact the brake disc and increases braking forces by eliminating the need to overcome the play between the wrap spring and the guide sleeve during adjustment, resulting in improved braking efficiency.

Implementation Method 1

a wrap spring (4) arranged in the guide sleeve (3) in a loop-like manner, with the wrap spring (4) acting on the guide sleeve (3) in the circumferential direction

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the grooved ring (5) being coupled to a closure cap (6) via a torsion spring (7)

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Implementation Method 3

the brake pads (212, 213) are in contact with the brake disc during a braking process

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3685069B1Disc brake actuator
Publication Date: 2021.07.14 ZF CV SYST EURO BV
  • EP3685069B1 patent drawingFigure 1
  • EP3685069B1 patent drawingFigure 2~2a
  • EP3685069B1 patent drawingFigure 2b~2c

AI summary

The invention relates to an adjusting device for a disc brake for adjusting the wear for brake pads. The adjusting device comprises a guide sleeve in which a wrap spring is arranged, a groove ring which encompasses the guide sleeve, wherein the groove ring is coupled to a closure cap via a torsion spring, and an opening ring encompassing the groove ring.