Development of the design of the final drive of the tractor (Prototype Belarus-82)

Contents

SUMMARY

P

INTRODUCTION

1.ANALYSIS OF STRUCTURAL ANALOGUES

1.1.The purpose, classification and requirements for transmissions

2.BASE SELECTED DIAGRAM

3.KINEMATIC AND ENERGY CALCULATION

4. CALCULATION OF ENGAGEMENT PARAMETERS

4.1.Select material for gear and wheel

4.2. Calculation of allowable contact stresses during endurance calculation

4.3.Define allowable contact stresses when calculating contact strength under maximum load

4.4. Design calculation for contact endurance

4.5. Test calculation for endurance by contact stresses

4.6. Check calculation for contact strength at maximum load

4.7.Determination of allowable bending stresses during endurance calculation

4.8.Define allowable stresses for maximum load bending strength

4.9.Valid Bending Endurance Calculation

4.10.Verification calculation for bending strength by maximum load

4.11.Apex diameter of gear and wheel teeth

4.12.Diameter of gear and wheel teeth recesses

5. SHAFT STRENGTH CALCULATION

6. DESIGN OF GEAR SHIFTING MECHANISM

7. LUBRICATION SELECTION. DEVELOPMENT OF OPERATIONAL MEASURES

7.1.Select gearbox lubrication

7.2.Development of operation measures

CONCLUSION

Literature

APPLICATION

Summary

This course project is devoted to the development of the final transmission of a wheeled tractor. The MTZ-80 tractor transmission was taken as the base model.

During the course project, an analysis of the existing final gear designs was carried out. Justification of selected final transmission scheme is given, analogue of which is final transmission of MTZ-80 tractor. Kinematic and energy calculations of gears, calculation of engagement parameters of the most loaded gear and strength calculation of shafts were also made, bearings were checked for durability. Safety and maintenance measures have been developed.

Volume of explanatory note: page: 51, figures: 10, tables: 2.

Introduction

Agricultural production is one of the most important sectors of the economy of the Republic, ensuring an increase in the standard of living of the people and the development of industry.

Recently, powerful tractors have been used on the territory of our Republic. The main reason for the use of powerful tractors in agriculture is economic. Equipping the farm with powerful equipment determines the possibility of successful labor-intensive work at the most profitable moment and in a short time. However, it must be remembered that when they are misused, costs increase dramatically. In Belarus there are certain trends in the development of tractor systems. In the near future, transmissions with mechanical speed gearboxes will be used. In order to facilitate the change in the speed of movement and avoid the cost of stopping and subsequent acceleration, gear gears of constant engagement with gearshift without breaking the power flow will be widely used in them. Structurally, this is carried out using hydraulically controlled couplings.

In this course design, it is necessary to develop the final transmission of the MTZ80 wheeled tractor. The final transmission serves to increase the total gear ratio of the power transmission and provide a predetermined ground clearance.

Shortening the development and development time of new equipment, increasing its productivity and reliability requires the development of computer-aided design systems, the use of design methods based on unified block-modular and basic structures,

complex automation of machines using built-in microprocessors.

The use of computer-aided design systems is impossible without the development of mathematical models of machines as complex dynamic systems and their components. Optimizing the parameters of machines requires a justification for choosing an optimization criterion. The complexity and breadth of the problem practically precludes optimization on only one criterion, since such a solution may be far from optimal for some other, sufficiently significant criteria. Obviously, the orientation towards multi-criteria optimization with independent criteria is the most correct.

Recently, there has been a tendency to ensure the complete reversibility of tractors of all classes and assignments, as well as the installation of two (front and rear) power take-off shafts (PTO).

Hydrostatic transmissions are of great use, which, despite the lower efficiency values ​ ​ compared to mechanical ones, still make it possible to increase the productivity of the tractor when performing a complex of agricultural tweening operations. First of all, hydrostatic drives will be used as hydrostatic undercarriers, power transmissions of the front driving axle, transmissions of special types of tractors with complex kinematics of the power drive and with strict requirements for layout and maneuverability, designed for the treatment of especially valuable crops, the cost of which is significantly higher than the cost of technical means for their cultivation. The cost of hydraulic transmissions of especially high power is 2-3 times higher than the cost of mechanical transmissions.

Transmissions with hydraulic transformers are most effective on industrial tractors.

The development of running systems of caterpillar tractors is following the path of using more progressive compression systems (caterpillars with low-pressure pneumatic rolls, hydraulic shock absorbers), on tractors with high pressure on the soil (marsh, reclamation) - rubber-cord and rubber-metal caterpillars.

The creation of general-purpose tractors with four driving wheels made it possible to improve the traction chain qualities of wheeled tractors, expanded the possibilities of using wheeled tractors to carry out the entire range of agricultural work in the farms of the main grain zones of the country. Calculations show that tractors with all driving wheels are economically viable with an engine power of 120 hp or more.

Conclusion

During the course project, the existing analogues of the final gear designs were compared, and all the necessary calculations were also carried out to design the final gear of the MTZ80 wheeled tractor. Calculations included: kinematic and energy calculations of the tractor transmission; calculation of final gear engagement parameters, calculation of end gear shaft strength.

During the calculations, the following parameters were obtained:

The gear ratio of the final transmission was.

Torque on the final gear was;

Final transmission power was kW;

The final gear engagement module was