Brake Pad Guide Coating for Low Residual Torque

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Solution Overview

Problem

Vehicle braking units for disc brakes experience residual torque due to poor alignment or anomalies in brake calipers and actuators, leading to abnormal pad wear and increased fuel consumption and emissions.

Innovation Solution

The integration of polymeric resin sliding coatings with solid lubricants like PTFE and molybdenum sulfide on guide surfaces within the brake caliper unit and brake pads, which are cured at high temperatures to reduce friction and torque.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional brake pads are used without special coatings, then the braking function is maintained, but residual torque occurs due to poor alignment or actuator anomalies leading to abnormal pad wear and increased fuel consumption

Engineering Contradiction:
Improvebraking functionVSAvoidresidual torque
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies a sliding coating specifically to the guide surfaces of the brake pad, rather than coating the entire brake pad or using special low friction seals on pistons. This localized application targets the specific area where friction causes residual torque, allowing the braking function to remain unchanged while reducing the harmful residual torque effect

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sliding coating acts as an intermediary layer between the guide surfaces of the brake pad and the support structure. This intermediate layer with solid lubricants reduces direct metal-to-metal or material-to-material contact friction, thereby mediating the interaction to minimize residual torque generation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If special low friction seals are used on pistons to reduce residual torque, then the braking function is maintained, but the solution does not effectively overcome the residual torque problem

Engineering Contradiction:
Improvebraking functionVSAvoidresidual torque
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the friction reduction function from the piston seals and relocates it to the guide surfaces of the brake pad. Instead of modifying the actuator system, the solution takes out the problematic friction interface and applies the sliding coating directly to the brake pad guide surfaces where it can more effectively reduce residual torque

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-generated harmful factors

If guide surfaces are covered with sliding coating containing solid lubricants, then residual torque is reduced, but the manufacturing process becomes more complex

Engineering Contradiction:
Improveresidual torqueVSAvoidcoating application process
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The sliding coating is formulated as a composite material combining polymeric resin with dispersed solid lubricants (PTFE and/or molybdenum sulfide). This composite structure allows the coating to be applied as a slurry or paste that can be brushed or sprayed onto the guide surfaces, then cured to form a durable low-friction layer, balancing manufacturing feasibility with performance

Inventive Principle:
Principle #40Composite materials

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 solution significantly reduces residual torque in braking systems, allowing brake pads to return to their original position after use, thereby minimizing wear and energy consumption.

Implementation Method 1

a sliding coating or layer consisting of a polymeric resin layer having solid lubricants and/or anti-friction materials dispersed within the polymeric resin layer

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

The sliding coating or layer is baked/cured at a temperature equal to or greater than 300°C and preferably between 350°C and 500°C, for between 20 to 60 minutes

Methodology Applied
Scientific EffectCuring:

Data Source

PatentEP3325838B1A vehicle braking unit, brake pad and associated methods
Publication Date: 2022.08.31 ITT ITAL SRL
  • EP3325838B1 patent drawingFigure 1
  • EP3325838B1 patent drawingFigure 2~3
  • EP3325838B1 patent drawingFigure 4~6

AI summary

A vehicle braking unit (3) comprising a support (5) designed to be positioned in use close to an element to be braked (4), braking elements (6) which are carried in a movable way by the support, actuation elements (7) which are carried by the support for pushing the braking elements against the element to be braked and first and second guide surfaces (8,9) that are integral, respectively, to the braking elements and to the support, and that cooperate together to guide and support the braking elements when they are moved towards the element to be braked by the activation of the actuation elements; the first and/or the second guide surfaces (8,9) are covered by a sliding coating (16) consisting of a polymeric resin layer with solid lubricants and/or anti-friction materials being dispersed therein, that has been cured at a temperature greater than 300°C.