Curved Leaf Spring Brake Pad for Heavy Vehicle Rattle Reduction

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Solution Overview

Problem

Heavy vehicle disc brakes experience rattling and vibration due to gaps between brake pads and abutments, and the use of leaf springs to mitigate this increases the mass and complexity of the brake pads.

Innovation Solution

A brake pad design featuring a curved leaf spring mounted to the backplate, which urges the pad circumferentially to reduce rattling and enhance retention, with the spring's shape and orientation optimizing contact with the abutment surfaces and aligning with the rotor's direction during braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If leaf springs are added to urge the brake pad circumferentially to reduce rattling, then the stability and retention of the brake pad is improved, but the mass and complexity of the brake pad increases

Engineering Contradiction:
Improvebrake pad stabilityVSAvoidbrake pad complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The spring is integrated directly into the brake pad structure by mounting it to the backplate, merging the retention function with the pad assembly. This eliminates the need for separate retention mechanisms and reduces overall system complexity while maintaining stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring has a curved configuration that follows the circumferential direction of the brake rotor. This curved shape allows the spring to effectively urge the pad circumferentially against the rotor, reducing rattling while accommodating the rotational geometry of the brake system.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Stability of the object's composition

If the backplate is enlarged to provide formations for locating leaf springs, then the retention and stability of the brake pad is improved, but the mass of the brake pad increases

Engineering Contradiction:
Improvebrake pad retentionVSAvoidbrake pad mass
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

Instead of enlarging the entire backplate, the spring is mounted at a specific location on the backplate. This localized approach provides the necessary retention function only where needed, avoiding unnecessary mass addition to the entire brake pad assembly.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The backplate is designed with a specific mounting location for the spring rather than requiring a large enlarged structure. This segmentation allows the retention function to be achieved with minimal modification to the backplate geometry, thus minimizing mass increase.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If clearance remains between the brake pad and circumferential abutments, then the ease of operation and sliding is improved, but rattling and vibration occur

Engineering Contradiction:
Improvepad sliding capabilityVSAvoidrattling and vibration
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The spring provides a dynamic circumferential urging force that maintains optimal contact between the brake pad and the rotor. This dynamic force reduces rattling and vibration by eliminating excessive clearance, while still allowing the necessary sliding motion for pad operation during braking.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring pre-urges the brake pad circumferentially before braking occurs, maintaining optimal contact and positioning. This preliminary action ensures that the pad is properly positioned and reduces rattling, while still allowing the pad to slide when braking forces are applied.

Inventive Principle:
Principle #10Preliminary action

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 solution effectively reduces brake pad rattling and enhances retention within the support structure, minimizing mass and complexity while maintaining robustness and reducing impacts on abutments.

Implementation Method 1

a first spring forming part of a first circumferential end surface of the brake pad and arranged to contact a first circumferential pad abutment surface and urge the brake pad, in use, towards a second circumferential pad abutment surface

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3409970B1A brake pad
Publication Date: 2023.03.22 MERITOR HEAVY VEHICLE BRAKING SYSTEMS (UK) LIMITED
  • EP3409970B1 patent drawingFigure 1
  • EP3409970B1 patent drawingFigure 2
  • EP3409970B1 patent drawingFigure 3

AI summary

A brake pad (511a) for a heavy vehicle disc brake, the brake pad comprising a layer of friction material having a friction face for contacting and retarding rotation of a rotor, the brake pad (511a) defining a first circumferential surface (577a) and a second (577b) circumferential surface for contact with first (575a) and second (575b) corresponding circumferential pad abutment surfaces of a disc brake in use. The brake pad (511a) further comprising a first spring (540) forming at least part of the first circumferential surface and arranged to contact the first circumferential pad abutment surface (575a) and urge the brake pad, in use, towards the second circumferential pad abutment surface (575b).