Disc Brake Guide Assembly With Non-Circular Anti-Rotation Sleeve

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Solution Overview

Problem

Conventional disc brake systems experience bolt loosening due to sleeve rotation and subsequent frictional transmission of torque, especially during frequent forward and reverse vehicle movements, which prior solutions have inadequately addressed by focusing on symptom rather than cause.

Innovation Solution

The implementation of a guide assembly with non-circular cross-sectional profiles for the sleeve and receiving portions of the brake carrier, which rotationally engages the sleeve to the brake carrier, restricting undesirable sleeve rotation and preventing bolt loosening by ensuring proper alignment and surface contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional smooth outer sleeve and bolt arrangement is used, then the guide assembly is simple and easy to manufacture, but the bolt may rotate and loosen during vehicle forward and reverse movements

Engineering Contradiction:
Improvebolt retentionVSAvoidguide assembly structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by providing the sleeve with a non-circular cross-sectional profile (such as D-shaped, rectangular, or oval) that corresponds to a matching non-circular profile in the brake carrier. This asymmetric geometry prevents rotational movement of the sleeve relative to the brake carrier, thereby preventing bolt loosening without requiring additional locking components or complex structures.

Inventive Principle:
Principle #4Asymmetry

2Reliability

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

Engineering Contradiction:
Improvebolt retentionVSAvoidguide assembly structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the unnecessary bolt component by designing a guide assembly where the sleeve's non-circular profile directly engages with the brake carrier. This removes the need for separate locking mechanisms like lock patches or threaded fasteners, addressing the root cause (sleeve rotation) rather than just the symptom (bolt loosening).

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The non-circular sleeve profile inherently provides its own rotational constraint through geometric engagement with the brake carrier. The structure is self-locking and self-restraining, eliminating the need for additional locking components or complex assembly procedures.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the sleeve is allowed to rotate freely, then the guide assembly allows smooth caliper movement, but torque is frictionally transmitted to the bolt causing it to loosen

Engineering Contradiction:
Improvecaliper slidingVSAvoidbolt retention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The asymmetric non-circular profile of the sleeve prevents rotational movement while maintaining smooth linear sliding motion. The geometry allows the caliper to slide along the guide pin without restricting the necessary degrees of freedom, while simultaneously preventing unwanted rotation that would transmit torque to the bolt.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3101301B2Guide assembly
Publication Date: 2024.03.06 MERITOR HEAVY VEHICLE BRAKING SYSTEMS (UK) LIMITED
  • EP3101301B2 patent drawingFigure 1
  • EP3101301B2 patent drawingFigure 2
  • EP3101301B2 patent drawingFigure 3a~3c

AI summary

The present invention relates to a guide assembly for a disc brake. To counter rotational torque, the guide assembly comprises a guide pin comprising a sleeve with a sleeve portion, and a receiving portion of a brake carrier to receive the sleeve portion; wherein the sleeve portion and receiving portion have corresponding non-circular cross-sectional profiles such that, when the sleeve portion is received and aligned in the receiving portion, rotation of the sleeve relative to the brake carrier is thereby at least restricted. By restricting the rotation of the sleeve, the transmission of rotation from the sleeve to a fastener, and consequential loosening of the fastener, is restricted. The present invention further relates to a disc brake comprising a brake carrier, a caliper and at least one guide assembly. If the receiving portion is a recess disposed in the brake carrier, a method of manufacturing the recess in the brake carrier comprises cutting the recess in the brake carrier with a circular inner edge region and a non-circular inner edge region.