Disc Brake Guide Sleeve Interlock to Prevent Guide Bolt Loosening

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Solution Overview

Problem

Disc brake guide bolts tend to loosen due to rotational movement of the guide sleeve, which is transmitted as friction to the bolt, especially under repeated forward and reverse vehicle movements, with previous solutions only addressing the symptom rather than the cause.

Innovation Solution

A rotational fixing mechanism that interlocks the guide sleeve and brake carrier to restrict both rotational and translational movements, using a connector system with cavities and deformable parts to create a press-fit connection, preventing undesirable movement and thus preventing bolt loosening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lock patches are used to inhibit rotation of the guide bolt, then the guide bolt loosening is prevented, but the solution only addresses the symptom rather than the cause

Engineering Contradiction:
Improveguide bolt retentionVSAvoidfixing mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the source of the problem by removing the guide sleeve's rotational capability entirely. Instead of applying corrective measures to the guide bolt (lock patches), the invention directly addresses the root cause by making the guide sleeve non-rotatable through the deformable receiving portion that permanently deforms upon assembly to lock the sleeve in place.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than trying to prevent the guide bolt from loosening after rotation occurs, the invention inverts the approach by preventing the guide sleeve from rotating in the first place. This fundamental reversal eliminates the need for lock patches and other corrective measures on the bolt.

Inventive Principle:
Principle #13The other way round (Inversion)

2Device complexity

If the guide sleeve is allowed to rotate freely, then the assembly is simple, but the guide bolt loosens under repeated forward and reverse vehicle movements

Engineering Contradiction:
Improveguide assembly simplicityVSAvoidguide bolt retention
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The deformable receiving portion is pre-configured in the brake carrier before assembly. During the assembly process, the receiving portion deforms to create a permanent interference fit with the guide sleeve, establishing the rotational constraint before the brake assembly begins operation. This preliminary action ensures reliability without adding complex moving parts.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The receiving portion undergoes a parameter change from a deformable state during assembly to a locked state after deformation. This permanent deformation changes the physical state of the receiving portion, creating a reliable rotational constraint that maintains guide bolt retention under repeated vehicle movements.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If lock patches are used to address guide bolt loosening, then bolt retention is improved, but the underlying cause of sleeve rotation is not addressed

Engineering Contradiction:
Improveguide bolt retentionVSAvoidassembly process simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent removes the need for lock patches entirely by extracting the rotational movement from the guide sleeve through the deformable receiving portion mechanism. This eliminates the symptom-based solution and addresses the root cause, simplifying both the component list and assembly process.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If the guide sleeve rotation is restricted through proper inter-locking, then bolt loosening is prevented, but the device complexity increases

Engineering Contradiction:
Improveguide bolt retentionVSAvoidfixing mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the rotational constraint function directly into the brake carrier structure through the deformable receiving portion. Rather than adding a separate fixing mechanism, the receiving portion itself performs the inter-locking function by deforming during assembly to create a permanent mechanical constraint, thereby maintaining simplicity while ensuring reliability.

Inventive Principle:
Principle #5Merging (Combining)

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

Effectively inhibits rotational and translational movements of the guide sleeve relative to the brake carrier, preventing bolt loosening and enhancing assembly alignment, thereby ensuring stable braking performance and reducing operator error.

Implementation Method 1

The receiving portion may be deformable during the assembly of the rotational fixing

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 2

the rotation of the guide sleeve and the rotation of the guide bolt being frictionally transmitted

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3617542B1Rotational fixing for a guide pin of a disc brake
Publication Date: 2022.02.09 MERITOR HEAVY VEHICLE BRAKING SYSTEMS (UK) LIMITED
  • EP3617542B1 patent drawingFigure 1
  • EP3617542B1 patent drawingFigure 2
  • EP3617542B1 patent drawingFigure 3a

AI summary

The present invention relates to rotational fixing and method for fixing a guide pin of a disc brake. The fixing comprises a sleeve portion of a guide sleeve (28), a receiving portion of a brake carrier (10) to receive the sleeve portion, and an inter-connection (300,302,304) to engage the sleeve portion and receiving portion so as to at least restrict rotation of the guide sleeve relative to the brake carrier when the sleeve portion is received by the receiving portion. The inter-connection may be further configured to engage the sleeve portion and receiving portion so as to at least restrict translation of the guide sleeve relative to the brake carrier when the sleeve portion is received by the receiving portion. The inter-connection may comprise a protrusion extending from the sleeve portion or and receiving portion and an indent in the corresponding portion in which the protrusion can be located when the sleeve portion is received by the receiving portion and the protrusion and indent are aligned.