Disc Brake Pad Spring Assembly for Axial Pad Retraction

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Solution Overview

Problem

Existing disc brake spring assemblies often apply uneven elastic bias, leading to residual torque, uneven pad wear, and suboptimal braking performance due to direct action at the radial edge of the pads, which can cause incomplete detachment and unplanned pad positioning.

Innovation Solution

A disc brake assembly featuring two pads and a spring configured to apply elastic bias directly in the axial direction, with the spring connected only to the pads, allowing for flexible mounting and minimizing contact with the caliper, ensuring axial action and maintaining pad parallelism to the brake disc, even under wear conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the spring connects to the caliper at coupling portions, then the spring can be fixed in position, but this requires designing springs specifically for each caliper and allocates caliper space for coupling portions

Engineering Contradiction:
Improvespring positioningVSAvoidcaliper design
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring is extracted from the caliper body and connected directly to the pads only, removing the need for coupling portions on the caliper. This simplifies the caliper design while maintaining spring functionality through direct pad attachment.

Inventive Principle:
Principle #2Taking out (Extraction)

2Force

If the spring abuts against the apical portion of the pads, then the spring can apply distancing force, but this causes uneven pad displacement and residual torque

Engineering Contradiction:
Improvedistancing forceVSAvoidresidual torque
Core Design Contradiction:
ForceVSObject-generated harmful factors

Solution Approach 1:

The spring action is redirected from radial force application at the pad apex to axial force application through the pad thickness. By connecting to the inner and outer surfaces of the pad, the spring applies force in the axial dimension rather than radially, eliminating residual torque while maintaining effective pad distancing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Length of moving object

If the spring applies elastic bias at the radial edge of pads, then pad separation can be achieved, but this causes unplanned pad positioning and uneven wear

Engineering Contradiction:
Improvepad separationVSAvoidpad positioning
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The spring connection moves from radial edge contact to axial contact through the pad thickness. This dimensional change ensures force application along the pad's thickness axis, maintaining precise pad positioning parallel to the brake disc while achieving effective separation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Adaptability or versatility

If the spring is connected only to the pads, then flexible mounting and axial action are achieved, but the spring must maintain connection stability during pad wear

Engineering Contradiction:
Improvemounting flexibilityVSAvoidconnection stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The spring connection is designed to dynamically adapt to pad wear through rotational movement about the axial axis. This dynamic capability allows the spring to maintain stable axial connection throughout the pad wear cycle while preserving mounting flexibility and connection reliability.

Inventive Principle:
Principle #15Dynamics

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 configuration ensures balanced elastic action on both pads, reducing residual torque, maintaining pad parallelism, and improving braking performance by applying a consistent axial bias, thus enhancing the flexibility and effectiveness of the spring assembly.

Implementation Method 1

a spring (15) configured to apply an elastic bias on the pads (6) so as to bias the pads (6) elastically away from the brake disc (3)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3899306B1Assembly of at least two brake pads and at least one spring
Publication Date: 2024.06.26 FRENI BREMBO SPA
  • EP3899306B1 patent drawingFigure 1~2
  • EP3899306B1 patent drawingFigure 3~4
  • EP3899306B1 patent drawingFigure 5~7

AI summary

An assembly (100) comprising: • - at least two pads (6) having a support plate (7) and a friction material coating (8), each of said at least two pads (6) being adapted to be accommodated in a pocket of a caliper so that each of said at least two pads (6) can be positioned on a side of a brake disc (3) of a disc brake facing opposite braking surfaces; said brake disc (3) being a rotor adapted to rotate about a rotation axis • - at least one spring (15), shaped to be arranged straddling the disc brake (3), wherein said spring (15) applies an elastic bias on the pads (6) so as to bias the pads (6) elastically away from the brake disc (3); wherein said at least one spring (15) is configured to be directly connected only to the pads (6); said support plate (7) comprises at least one plate coupling portion (37), wherein, in a section of said plate coupling portion (37) on a plane containing the axial direction and the radial direction, said plate coupling portion (37) comprises: • - an inner lower edge (25), adapted to face the brake disc (3) in the radially inward direction or towards the disc rotation axis; • - an inner upper edge (26), adapted to face the brake disc (3) in the radially outward direction or opposite to the disc rotation axis; • - said inner upper edge (26) continues on a direct upper surface (27) according to an axial direction parallel to said disc rotation axis, thus forming an upper spring-coupling plate portion edge; and wherein said spring (15) is always in contact exclusively with: • - said inner lower edge (25) and • - said upper spring-coupling plate portion edge.