Disc Brake Pad Spring Geometry for Reliable Pad Detachment

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Solution Overview

Problem

Existing disc brake systems with cross-shaped expansion springs face challenges in ensuring complete detachment of brake pads from the disc when the brake is deactivated, leading to residual braking torque, uneven pad wear, and sensitivity to geometric and frictional variations.

Innovation Solution

A spring design for disc brake pads that includes an elongated plate bent into a descending fixing stretch, an ascending resting stretch, and an arch-shaped return stretch, which applies a more intense and uniform axial elastic force to maintain pad detachment from the disc, reducing sensitivity to wear and operational conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the axial elastic force is insufficient, then the pads can be retained in lowered position, but complete and reliable detachment from the brake disc is not ensured

Engineering Contradiction:
Improvepad detachment reliabilityVSAvoidresidual braking torque
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

By changing the application angle to 45°-60°, the spring generates sufficient axial force to ensure complete and reliable pad detachment, eliminating residual braking torque. The force balance equation is fundamentally altered to favor complete separation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The spring is designed to apply preliminary axial force that actively prevents the harmful effect of residual braking torque by ensuring complete pad detachment before any unintended contact can occur.

Inventive Principle:
Principle #9Preliminary anti-action

2Device complexity

If the application angle is less than 15°, then the spring configuration is simple, but the constraint conditions of the pads are uncertain and variable over time

Engineering Contradiction:
Improvespring configuration complexityVSAvoidpad constraint precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent specifies a precise application angle range of 45° to 60°, which creates well-defined constraint conditions. This parameter specification ensures that the axial component of the elastic force is sufficient and consistent, reducing variability in pad constraint conditions throughout the pad's life cycle.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the axial elastic force varies with pad wear, then the spring structure remains simple, but the distancing function is not ensured during the entire life cycle of the pad

Engineering Contradiction:
Improvespring structure complexityVSAvoidpad distancing function duration
Core Design Contradiction:
Device complexityVSDuration of action of stationary object

Solution Approach 1:

By optimizing the application angle to 45°-60°, the spring maintains a more stable axial force component throughout pad wear. The geometric relationship between the spring and pad creates more consistent constraint conditions, ensuring the distancing function is maintained throughout the entire pad life cycle.

Inventive Principle:
Principle #35Parameter changes

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 spring design effectively reduces residual braking torque, ensures uniform pad wear, and enhances the robustness of the elastic constraint system, maintaining consistent pad detachment throughout the pad's life cycle.

Implementation Method 1

a spring for elastically retaining and positioning the pads in a disc brake caliper

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

to reduce the vibrations of the pads

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP3810954B2Spring for friction pads in a disc brake caliper
Publication Date: 2025.06.11 FRENI BREMBO SPA
  • EP3810954B2 patent drawingFigure 1~2
  • EP3810954B2 patent drawingFigure 3~5
  • EP3810954B2 patent drawingFigure 6~7

AI summary

A spring (22) for friction pads which can be associated with a caliper of a disc brake for pushing the friction pads away from a brake disc, wherein the spring (22) comprises a descending fixing stretch (24), an ascending resting stretch (25), opposite to the fixing stretch (24), and an arch-shaped return stretch (26) formed between the fixing stretch (24) and the resting stretch (25), wherein the return stretch (26) extends from a narrowing region (29), in which the fixing stretch (24) and the resting stretch (25) locally approach each other in form of widened loop with respect to the narrowing region (29), to a lower apical region (28) of the spring (22), wherein the fixing stretch (24) forms a fixing seat for fixing a fixing portion of the friction pad and the resting stretch (25) forms a contact portion (32) for a free resting with possibility of slipping of the spring (22) against a contact surface of the caliper.