Vehicle Transmission Design - Drawings

Contents

Introduction

1 Functional design of the vehicle transmission

1.1 Development of technical requirements and setting of tasks

functional design of transmission

1.2 Overview and analysis of existing structures and selection of technical solutions

1.3 Synthesis of structure and development of kinematic scheme of trans-

missions

2 Functional design of transmission mechanism

2.1 Setting of tasks of functional design of mechanics

zma

Define and select the main parameters of the mechanism

Determination of basic parameters of gear wheels

Define basic parameters for controls

3 Design design of transmission mechanism

3.1 Transmission mechanism design

3.2 Determination of mechanism load modes

3.3 Mechanism Gear Durability Analysis

3.4 Design of mechanism shafts

3.5 Design of bearing supports

3.6 Substantiation of materials and hardening methods selection

main parts

3.7 Assessment of mechanism dimensions and efficiency

Conclusion

List of sources used

Appendix A

Introduction

Truck transmissions try to develop so that they guarantee the necessary dynamic and economic properties to the car, work silently, with high efficiency, are reliable, easy to maintain, have as small dimensions and weight as possible, as well as low cost.

Speed gearboxes, having a high efficiency (when transmitting full power, it is from 0.96 to 0.98), are simpler in design than stepless, cheaper in production and can automate the control process. They were the most common in trucks.

The necessary dynamic and economic qualities of the machine are achieved by correctly choosing the range of gear ratios in the gearbox, the number of gears and carefully selecting the gear ratio of each of them .

For commercial vehicles operating mainly in urban conditions, the range of gear ratios of modern transmissions is 5.0-8.0; for main tractors and off-road trucks, it is already 10-20. The number of transmissions in truck mechanical transmissions varies from 5 to 16.

Increasing the number of stages in the box allows better use of engine power, and accordingly, less fuel consumption, increases average speed, and as a result, higher car productivity and lower transportation costs. However, the increase in the number of stages in the box complicates and weights it, the size and cost of the unit increase, and the control drive of the box becomes more complicated.

Design design of transmission mechanism

3.1 Transmission mechanism design

For design, we adopted a complex gearbox, consisting of a basic 4-speed gearbox and a multiplier reduction gearbox located after the BCP.

The gearbox is designed to convert the engine power parameters when transmitting it to the driving wheels in order to obtain the necessary value and direction of speed, as well as stopping and long-term parking at the operating engine.

Thus, we will design a 3-shaft 4-speed basic gearbox with a coaxial arrangement of the input and output shafts and a two-speed gearbox-multiplier. Such a gearbox will have 8 forward gears and one reverse gear. The CP ratios were shown in table 2.2.1 above. Gear shifting will be carried out using inertial synchronizers with push cracks, which will be installed on all gears except reverse.

The main elements providing functional purpose of the gearbox are: crankcase, input, intermediate and output shafts of the base gearbox and multiplier (moreover, the output shaft of the base gearbox is the input shaft of the multiplier), gears, bearings, energy flow control elements (synchronizers and gear couplings).

Conclusion

As a result of work on the course project, a truck transmission weighing 8 tons was designed with the development of a complex eight-speed gearbox.

At the same time, during the design process, the structure was synthesized and a kinematic scheme of the designed gearbox was developed. All calculations were made using computers and CADs, which corresponds to modern design trends.

It should be noted that the design of this gearbox can subsequently be improved: a reduction in the weight of the main KP mechanisms due to the use of new materials and the optimization of their shape and size.