Automotive Transmissions

Transcription

1 Gisbert Lechner Harald Naunheimer Automotive Transmissions Fundamentals, Selection, Design and Application In Collaboration with Joachim Ryborz With 370 Figures J i Springer

2 Contents Terms and Symbols XVII 1 Introduction Preface History of Vehicle Transmissions Fundamental Innovations Development of Vehicles and Drive Units Stages in the Development of Vehicle Transmissions Development of Gear-Tooth Systems and other Transmission Components Development of Torque Converters and Clutches Investigation of Phenomena: Transmission Losses and Efficiency Overview 21 2 Overview of the Traffic - Vehicle - Transmission System Fundamental Principles of Traffic and Vehicle Engineering The Significance of Motor Vehicles in our Mobile World Trends in Transport Engineering Passenger and Goods Transport Systems Alternative Transport Concepts The Market and Development Situation for Vehicles, Gearboxes and Components Market Situation and Production Figures Development Situation Basic Elements of Vehicle and Transmission Engineering Systematic Classification of Vehicles and Vehicle Use Why do Vehicles Need Gearboxes? Main and Auxiliary Functions of Vehicle Transmissions, Requirements Profile Interrelations: Direction of Rotation, Transmission Ratio, Torque Road Profiles, Load Profiles, Typical Vehicle Use and DriverTypes Fundamental Performance Features of Vehicle Transmissions Service Life and Reliability of Transmissions 50

3 X Contents Centre Distance Characteristic Value Gearbox Mass Characteristic Value Gearbox Cost Characteristic Value Transmission Noise Gearbox Losses and Efficiency Transmission Design Trends 56 3 Mediating the Power Flow Power Requirement Wheel Resistance Adhesion, Dynamic Wheel Radius and Slip Air Resistance Gradient Resistance Acceleration Resistance Total Driving Resistance Efficiency Map Diversity of Prime Movers Overview Electric Drive Hybrid Drive Power Output, Combustion Engine Characteristic Torque/Engine Speed Characteristic Engine Spread, Throttle Map Consumption Map 75 4 Power Conversion: Selecting the Ratios Power Train Speed Converter for Moving Off Total Ratio and Overall Gear Ratio Overall Gear Ratio Selecting the Largest Power-Train Ratio Selecting the Smallest Power-Train Ratio Final Ratio Selecting the Intermediate Gears Saw Profile Diagram Geometrical Gear Steps Progressive Gear Steps Continuously Variable Transmissions 90 5 Matching Engine and Transmission Traction Diagram Deriving a Traction Diagram (Example) 95

4 XI Engine Braking Force Geared Transmission with Dry Clutch Geared Transmission with Trilok Converter Vehicle Performance Maximum Speed Climbing Performance Acceleration Performance Fuel Consumption Calculating Fuel Consumption (Example) Determining Fuel Consumption by Measurement Reducing Fuel Consumption Continuously Variable Transmissions Emissions Dynamic Behaviour of the Power Train, Comfort 109 Vehicle Transmission Systems: Basic Design Principles Arrangement of the Transmission in the Vehicle Passenger Cars Tracks and Buses Four-Wheel Drive Passenger Cars Transverse and Longitudinal Dynamics with All-Wheel Drive Transmission Formats and Designs Transmission Format Transmission Design Basic Gearbox Construction Shifting with Power Interruption Shifting without Power Interruption Continuously Variable Transmissions without Power Interruption Gear-Sets with Fixed Axles, Countershaft Transmissions and Epicyclic Gears Fundamental Approaches for Part Functions, Evaluation Reverse Gear Passenger Car Transmissions Manual Passenger Car Transmissions Semi-Automatic Manual Passenger Car Transmissions Fully Automatic Passenger Car Transmissions Continuously Variable Passenger Car Transmissions Commercial Vehicle Transmissions Single-Range Transmissions Multi-Range Transmissions Practical Design of Two- and Three-Range Transmissions Semi-Automatic Manual Commercial Vehicle Transmissions Fully Automatic Commercial Vehicle Transmissions Continuously Variable Transmissions for Commercial Vehicles 159

5 XII Contents 6.8 Transfer Gearboxes and Power Take-Offs Final Drives: Formats, Performance Limits, Transmission Ratios Final Drive Systems for Passenger Cars Final Drive Systems for Commercial Vehicles Differential Gears, Differential Locks and Locking Differentials Principles of Differential Gears The Need for Locking The Interlock Value Alternatives to Self-Locking Differentials Design of Gearwheel Transmissions for Vehicles Gearwheel Performance Limits Causes andtypes of Damage Calculating the "Tooth Failure" Performance Limit Calculating the "Pitting" Performance Limit Calculating the "Gear Scuffing" Performance Limit Estimating Centre Distance Estimating Face Widths Operational Integrity and Service Life The Wöhler Curve Load Profile and Enumeration Damage Accumulation Hypothesis Developing Low-Noise Transmissions Transmission Noise and Its Causes How Noise Reaches the Ear Assessment Criteria Countermeasures Specification and Design of Shafts Typical Problems in Vehicle Transmissions Configuration of Shafts in Vehicle Transmissions Designing for Stress and Strength Deflection Vibration Problems General Design Guidelines Transmission Drive-Shaft Strength Design Loading Bearing Reactions Spatial Beam Deflection Power and Torque Profiles Critical Cross-Section Stresses Preliminary Specification of the Shaft Diameter 218

6 XIII Designing for Fatigue Strength Designing for Operational Integrity Normal Shaft Materials Calculating Deformation Flow Chart for Designing Transmission Shafts 221 Gear Shifting Mechanisms, Layout and Design of Synchronisers Systematic Classification of Shifting Elements Shifting Elements for Geared Transmissions with Power Interruption Shifting Elements for Geared Transmissions without Power Interruption ParkingLock Synchroniser Functional Requirements Changing Gear Main Functions and Ancillary Functions Speed Synchronisation with Slipping Clutch Synchroniser Dimensions The Synchronising Process EaseofUse Design of Synchronisers Synchroniser Performance Limits Basis for Design Calculation Practical Design for Acceptable Thermal Stress Designing Locking Toothing for Locking Effect The Tribological System Materials Engineering Designs Detail Questions Alternative Transmission Synchronisers 259 Hydrodynamic Clutches and Torque Converters Principles Hydrodynamic Clutches and their Characteristic Curves Torque Converters and their Characteristic Curves The Trilok Converter Engine and Torque Converter Working Together Torque Converter Test Diagram, Interaction of Engine and Trilok Converter Practical Design of Torque Converters Engineering Designs Design Principles for Increasing Efficiency Torque Converter Lock-Up Clutch Power Split Transmission 275

7 XIV Contents 11 Notes on the Design and Configuration of Further Vehicle Transmission Design Elements Bearings Selecting Bearings Bearing Design Design of Roller Bearings Lubrication of Gearboxes, Gearbox Lubricants Bearing Lubrication Principles of Lubricating Gearwheel Mechanisms Selecting the Lubricant Selecting Lubricant Characteristics Lifetime Lubrication in Vehicle Gearboxes Testing the Scuffing Resistance of Gearbox Lubricants Gearbox Housing Gearbox Housing Design Venting Gearboxes Gearbox Sealing Seals for Static Components Seals for Rotating Components Seals for Reciprocating Round Components Practical Examples Vehicle Continuous Service Brakes Definitions Engine Braking Systems Retarders Actuation and Use Typical Designs of Vehicle Transmissions Manual Gearboxes Manual Passenger Car Gearboxes Manual Commercial Vehicle Gearboxes Semi-Automatic Manual Gearboxes Semi-Automatic Manual Passenger Car Gearboxes Semi-Automatic Manual Commercial Vehicle Gearboxes Fully Automatic Gearboxes Fully Automatic Passenger Car Gearboxes Fully Automatic Commercial Vehicle Gearboxes Further Examples Final Drives Typical Designs, Passenger Cars Typical Designs, Commercial Vehicles Differential Gears, Locking Differentials Four-Wheel Drives, Transfer Gearboxes 352

8 Contents XV 13 Engine and Transmission Management, Electronics and Information Networking Overview of Electronic Systems in Current Use Engine Management Transmission Control Automatic Master/Gearshifting Clutch Semi-Automatic Manual Transmissions, Automatic Gear Selection Fully Automatic Transmissions, Adaptive Gearshift Strategy Continuously Variable Transmissions Electronically Controlled Braking and Traction Systems Safety Concepts Overview of the Development Process, Product Planning and Systematic Engineering Design Product Life Cycles Product Planning The Development Process Systematic Engineering Linking Development and Production Computer-Aided Transmission Development, Driving Simulation Driving Simulation Extraneous Factors Route Data Set, Route Data Acquisition Driving Simulation Programs Classification Modular Construction Applications of Driving Simulation Reliability and Testing of Vehicle Transmissions Principles of Reliability Theory Definition of Reliability Statistical Description and Representation of the Failure Behaviour of Components Mathematical Description of the Failure Behaviour Using the Weibull Distribution Reliability with Systems Availability of Systems Reliability Analysis of Vehicle Transmissions System Analysis Qualitative Reliability Analysis 406

9 XVI Contents Quantitative Reliability Analysis Testing to Ensure Reliability Classifying Vehicle Transmission Test Programs Test Stands for the Test Programs 415 References 419 Index of Companies/Transmissions 439 Index of Names 441 Subject Index 442