Automotive Vibration Control Technology

Transcription

1 TrelleborgVibracoustic (Ed) Automotive Vibration Control Technology Fundamentals, Materials, Construction, Simulation, and Applications Vogel Business Media

2 isoprene natural isobuteneisoprene styrenebutadiene acrylonitrile hydrogenated vii Table of Contents Part 1 Fundamentals 1 Vibration Control Technology for the Automotive Industry 1 11 Fundamentals and requirements of vibration control technology 1 12 Vibration control technology in automotive engineering 1 2 Isolation, Damping, and Absorption 5 21 A material becomes predictable 5 22 The principles of vibration isolation 6 23 Fourpole theory: an approach to describing the isolation of high frequencies Mechanical impedance Mechanical fourpole systems Coupling of fourpole systems Isolation calculations using fourpole systems Transmission loss Transmission loss with reference to velocity Transmission loss with reference to force Insertion loss Example: shock absorber top mount for a car suspension Effects of damping and friction on isolation Introduction The effect of speedproportional damping The effect of friction Vibration absorption 27 3 Vibration Control Materials Introduction Elastomers an extraordinary class of materials Energy elasticity Entropy elasticity Base polymer or crude rubber (caoutchouc) Introduction Natural and synthetic rubber Elastomeric materials overview of typical material properties Introduction NR 3412 IR rubber 32 rubber BRbutadiene rubber SBR rubber CR chloroprene rubber NBR 3417 HNBR 3418 MR butadiene rubber 34 nitrile butadiene rubber 34 rubber 35

3 discovery ethylene epichlorohydrin polyester production an selfreinforcement engine viii Table of Contents 3419 EPDM ethylene propylene diene terpolymer rubber ACMacrylic rubber AEM FKM ECO acrylic rubber 36 fluorinated rubber 36 rubber VMQsilicone rubber AU and EU and polyether urethane rubber Natural rubber and history, properties and application Introduction Crude natural rubber processes and properties TSRtechnically specified rubber : Synthetic "natural rubber" NR compounds and vulcanizates typical properties Strength reinforcement Heat resistance aging Properties in cold conditions Applications Future prospects Compounding and vulcanization Ingredients of compounds Introduction Crosslinking systems Special case: thermoplastic elastomers (TPE) Fillers Plasticizers Antiaging agents Processing agents Production of raw compound Testing and approval Vulcameter testing Molding and vulcanization Compression molding Transfer molding Injection molding Rubbermetal bonding Elastomers for vibration control overview Aging resistance Cold resistance Temperature limits Component groups engineered materials Materials for chassis components Materials for spring elements and body mounts: applications for MCU Materials for power train components and transmission mounts 73

4 Table of Contents 3931 Material properties Shore hardness Materials for engine mounts Materials for torsional vibration dampers Materials for couplings and decoupling pulleys Materials for absorbers Materials for airsprings The future of elastomers in vibration control Bonding technology Substrates for bonded elastomer components Metals Plastics Metals and plastics Elastomers for bonded rubbermetal components Pretreatment of substrates Cleaning processes Blast cleaning Phosphating process for steel parts Conversion processes for aluminum Bonding agents for composite elastomer parts Historical development of bonding agents Physical and chemical principles of bonding Bonding agent manufacturers and their products Future trends in bonding agents The bonding mechanism Composition of bonding agents Reactions of bonding agents Reactions during vulcanizing Crosslinking reactions in bonding systems Application of bonding agents Application methods Measuring the thickness of bonding agent layers Bonding tests Bonding tests on finished components Tests on specimens Nondestructive testing Ruptures of bonded rubbermetal components Typical failure types Possible causes of failure Damage analysis From System Knowledge to a Better Component From system description to component specification From specification to component design Component design Spring design using finite element analysis Service life prediction and spring optimization Weight reduction by automatic contour optimization 127

5 xii Table of Contents 785 Switchable mounts Switchable engine mounts Electrically switchable engine mounts Pneumatically switchable hydromounts Switchable mounts with automatic diaphragm travel adjustment Active Vibration Control Introduction History AVC system options Openloop control Closedloop control AVC system components The actuator (options) The electrodynamic actuator The electronic control unit (ECU) The "error" sensor Case studies Outlook Responses to market requirements Functional improvements and cost reduction for engine and transmission mounts in connection with vehicle development Modular toolkits Introduction Further development of a toolkit with simple and unconventional solutions Special customized solutions Hydromount with integrated absorber Hydromount/switchable hydromount with double isolator Hydromount with automatic hydraulic idle absorber Hydromount with silicone supporting spring and local silicone protective cap Innovation: active mounts Summary Guiding principles for engine and transmission mount design Chassis Mounts Ride comfort or driving safety The sports car chassis Definition of "ride comfort" The definition of "safe handling" Rubbermetal suspension components Rubbermetal parts allow wheel spring travel Rubbermetal elements allow maintenancefree axles Rubbermetal components control suspension kinematics

6 Table of Contents xiii 824 Rubbermetal mounts support demanding specifications Rubbermetal mounts absorb bumps Rubbermetal elements isolate vibrations RubbertoMetal Mounts for Commercial Vehicles Engine mounts for medium and heavy trucks Design Systems Fixation Bump Stops Characteristic curves Available space Rubbertometal body Materials Elastomers Bracket materials Conclusion Chassis mounts Chassis with leaf springs (front/rear axle) Chassis with air springs Cab mounts Introduction Functions Technical requirements for component development Component design Service life and functionality Special mounts Battery case suspension Loads and requirements Component design Component configurations Control box mounts Air Springs The use of air springs in vehicle technology Fields of application Comparison of different spring systems for passenger cars Air spring system Level control with secondary air springs Hydropneumatic system Nivomat Adjustable suspension Active Body Control (ABC) Active Electromagnetic Body Control Advantages of air spring systems The configuration of an air spring system in the vehicle Air supply system 328

7 bellows rubber xiv Table of Contents Introduction Control units for air suspension systems Passenger car air spring requirements Function and physical principles of air springs The gas cushion as a spring The function of the air spring bellows Force and spring rate as design parameters How can the characteristic curve of an air spring be modified? Design and characteristics of air spring bellows Convoluted air springs, type 1B and 2B Convoluted air springs type 1A Rolling air springs Sleevetype air springs and connections (pushon, crimping, clamping) Thread orientation: Comparison of axial and crossply bellows Bellows properties and their effects on the vehicle Configuration and design of air springs Suspension strut or separate air spring Special requirements and designs Example of a passenger car application Example of a commercial vehicle application Example of a railway rolling stock application Production of air springs Components of air spring bellows Semifinished products and fabrics Bead inserts Reinforcing layers Nylon cord fabric Thread specifications Thread structure Selection of thread structure Structure of the bellows wall Design Responses to specific market requirements Torsional Vibration Dampers Cranktrain Introduction History Types of rubber torsional vibration dampers Introduction Pressed torsional vibration damper Vulcanized torsional vibration dampers Design of torsional vibration dampers Introduction Multibody simulation model 365

8 Table of Contents xv Solution of the differential equation system Validation of the simulation model Assessment of the results Outlook Damper isolator pulleys for auxiliary devices Introduction Structure of a damper isolator pulley Design of damper isolator pulleys The belt drive as a rotational vibration system Design criteria Validation of the simulation model Outlook Absorbers Linear absorbers Mode of 383 operation and applications of linear absorbers Transmission absorbers Steering wheel absorber/airbag absorber Chassis absorbers/convertible absorbers Active linear absorbers Hydraulic absorbers Design and sizing principles for linear absorbers Spring stiffness Damping Inertia mass Resonant frequency Design and structure of linear absorbers Responses to marketspecific requirements Rotational vibration absorbers Mode of operation and applications of rotational vibration absorbers Design principles for rotational vibration absorbers Design and structure of rotational vibration absorbers Response to marketspecific requirements Driveshaft mounting, centering, and torque transmission components Mode of operation and applications Design principles Fundamentals of Polyurethane (PUR) as a Springing and Damping Material Introduction Basic chemistry Isocyanates Polyols Polyethers Polyesters Catalysts 409

9 Table of Contents 134 Comparison MCU elastomers in automotive applications Microcellular Polyurethane (MCU) Principles of MCU applications Development examples of automotive components Component behavior prediction through FEA (Finite Element Analysis) Poisson's ratio Polynomial fit analysis Body mounts and suspension mounts Application examples for MCU Noise reduction Impact transmissibility Weight reduction Summary 424 Appendix 425 Index of chapters and authors 425 Acronyms 426 References 428 Further reading 431 Illustration credits 432 Index 433