Hybrid Roller for Cab Rear Mounting Noise Reduction

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Solution Overview

Problem

The existing rear driver's cab suspension systems in commercial vehicles experience rattling and squeaking noises due to polyamide rollers, which also fail to effectively absorb lateral forces and decouple vibrations between the chassis and the cab, leading to structure-borne noise transmission.

Innovation Solution

A hybrid roller is introduced, comprising an inner part made of polyoxymethylene (POM) for wear resistance and an outer part made of thermoplastic elastomer, such as polyolefin, to absorb vibrations and prevent noise, with a secure connection ensuring reliable performance without structural changes to the existing bearing elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polyamide rollers are used in the lateral guide unit, then the structure is simple and costs are low, but rattling and squeaking noises occur during driving

Engineering Contradiction:
Improveroller material simplicityVSAvoidrattling and squeaking noises
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The roller is constructed as a composite component with an inner part made of polyoxymethylene (POM) and an outer part made of thermoplastic elastomer. This composite structure combines the wear resistance and dimensional stability of POM with the vibration-damping and noise-reducing properties of the thermoplastic elastomer, thereby eliminating rattling and squeaking noises while maintaining manufacturing simplicity.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If polyamide rollers are used, then manufacturing costs are low, but vibration decoupling between chassis and cab is insufficient

Engineering Contradiction:
Improveroller manufacturing costVSAvoidvibration decoupling performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The hybrid roller combines polyoxymethylene (POM) for structural integrity with an outer layer of thermoplastic elastomer that provides superior vibration decoupling properties. The elastomer layer absorbs and dampens vibrations between the chassis and cab, significantly improving reliability in terms of vibration isolation while keeping manufacturing costs reasonable.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the material parameters of the roller by transitioning from homogeneous polyamide to a bimaterial construction with POM core and thermoplastic elastomer coating. This parameter change optimizes both mechanical strength and vibration-damping characteristics, achieving better vibration decoupling performance.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a hybrid roller with thermoplastic elastomer outer part is used, then vibration decoupling and noise reduction are improved, but manufacturing complexity increases

Engineering Contradiction:
Improvevibration decoupling effectivenessVSAvoidroller structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

While the hybrid roller does increase structural complexity compared to homogeneous rollers, the complexity is managed through integrated manufacturing processes where the thermoplastic elastomer outer part is molded onto the POM inner part as a single composite component. This approach minimizes assembly steps and keeps the overall manufacturing process relatively simple while achieving superior vibration decoupling.

Inventive Principle:
Principle #40Composite materials

4Object-generated harmful factors

If hybrid roller with two material parts is used, then noise transmission is reduced, but manufacturing process becomes more complex

Engineering Contradiction:
Improvestructure-borne noise transmissionVSAvoidroller manufacturing process
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The hybrid roller manufacturing process, while slightly more complex than single-material rollers, is streamlined through overmolding techniques where the thermoplastic elastomer is directly molded onto the POM core in a two-step injection process. This integrated approach creates a seamless composite structure that effectively reduces structure-borne noise transmission without requiring complex post-assembly operations.

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

The hybrid roller effectively absorbs lateral forces and vibrations, significantly reducing rattling and squeaking noises while maintaining vibration decoupling over large frequency ranges, enhancing driving comfort and safety without increasing costs or requiring structural modifications.

Implementation Method 1

the outer part having a thermoplastic elastomer... absorb vibrations and prevent noise

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 2

the outer part having a thermoplastic elastomer... absorb vibrations

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 3

the inner part having a thermoplastic synthetic material... for wear resistance

Methodology Applied
Scientific EffectWear resistance: Wear

Implementation Method 4

reduce friction and prevent rattling noises

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 5

the bearing arrangement having a spring and/or damper unit... absorb the forces acting on the driver's cab

Methodology Applied
Scientific EffectSpring cushioning: Spring

Implementation Method 6

spring and/or damper units... at least partially ensure vibration decoupling and/or damping

Methodology Applied
Scientific EffectDamper damping: Damping

Data Source

PatentEP2650195B1Rear mounting for the driver's cab of a utility vehicle
Publication Date: 2015.01.07 MAN TRUCK & BUS OESTERR
  • EP2650195B1 patent drawingFigure 1
  • EP2650195B1 patent drawingFigure 2
  • EP2650195B1 patent drawingFigure 3

AI summary

The invention relates to the rear mounting (1) of a commercial vehicle cab with a cross member (2) arranged transversely to the frame longitudinal members (4), which is attached on both sides to the frame longitudinal members (4) of a chassis frame by means of a bearing arrangement (3). The bearing arrangement (3) comprises a spring and/or damper unit (5) and a lateral guide (6) which are attached to different pivot points (2a, 2b) of the cross member (2), and the lateral guide (6) has a roller (12) arranged vertically within a guide (9) and attached to the cross member (2) by means of a fastening element (7, 13). The described technical solution is characterized in that the roller (12) is penetrated by at least one screw (13) or bolt, which...which is arranged to be vertically movable within a recess (11) of the guide (9), and the roller (12) has at least an inner part (14) and an outer part (15), wherein the inner part (14) is made of a thermoplastic material and the outer part (15) is made of a thermoplastic elastomer.