Disc Brake Guide Rod Bushing for NVH and Friction Reduction

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Solution Overview

Problem

Existing vehicle disc brake assemblies experience noise, vibration, and harshness due to contact between guide rods and the anchor bracket, which can be mitigated by using a bushing but increases manufacturing complexity or cost.

Innovation Solution

A bushing is adapted for use with a guide rod fastener in a vehicle disc brake assembly, reducing noise, vibration, and harshness without increasing manufacturing complexity or cost by evenly distributing the load and reducing friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a bushing is provided on one of the guide rods, then noise, vibration, and harshness are reduced, but manufacturing complexity increases

Engineering Contradiction:
Improvenoise, vibration, and harshnessVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies local quality by providing the bushing only on the leading guide rod where it is most needed to reduce noise, vibration, and harshness during brake application, while leaving the trailing guide rod without a bushing to maintain manufacturing simplicity. This selective application optimizes the balance between performance and manufacturing complexity.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If bushings are provided on all guide rods, then noise, vibration, and harshness are further reduced, but manufacturing cost increases

Engineering Contradiction:
Improvenoise, vibration, and harshnessVSAvoidmanufacturing cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent applies partial action by providing the bushing on only one guide rod (the leading guide rod) rather than all guide rods. This partial application is sufficient to achieve the primary goal of reducing noise, vibration, and harshness during brake application, while avoiding the increased manufacturing costs that would result from installing bushings on all guide rods.

Inventive Principle:
Principle #16Partial or excessive 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 bushing effectively reduces noise, vibration, and harshness in vehicle disc brake assemblies while maintaining manufacturing efficiency and cost-effectiveness by providing a consistent and reduced friction interface between guide rods and the anchor bracket.

Implementation Method 1

The noise, vibration, and harshness may be reduced by providing an elastomeric rod bushing on at least one of the guide rods

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The bushing is installed between the guide rod and the bore of the anchor bracket in which the guide rod extends

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3519715B1A vehicle disc brake assembly comprising elastic bushings
Publication Date: 2025.05.14 ZF ACTIVE SAFETY US INC
  • EP3519715B1 patent drawingFigure 1
  • EP3519715B1 patent drawingFigure 2
  • EP3519715B1 patent drawingFigure 3~4

AI summary

A vehicle disc brake assembly includes a brake caliper. The brake caliper has a lug through which a bore extends, the bore having an axis. A guide rod fastener extends through the bore and is secured to a guide rod. An elastic bushing is in the bore between the lug and the guide rod fastener, wherein a circumference of the bushing contacts the lug. A radial clearance is between the lug and the guide rod fastener. The radial clearance is perpendicular to the axis.