Kinematic calculation of worm-chain drive

Contents

Contents

1 Introduction

2 Motor selection and kinematic calculation

3 Calculation of worm gear

3.1 Selection of worm and worm wheel material

3.2 Determination of allowable contact stresses

3.3 Determination of allowable bending stresses

3.4 Design calculation

3.5 Check calculation by contact voltages

3.6 Check of gear teeth for bending

4 Calculation of chain transmission

4.1 Design calculation

4.2 Verification calculation

5 Preliminary calculation of shafts

5.1 Drive shaft

5.2 2nd shaft

5.3 Output shaft

6 Structural dimensions of gears and wheels

6.1 Worm Wheel

6.2 Chain Drive Asterisk

6.3 Driven Chain Transmission Asterisk

7 Selection of coupling on drive input shaft

8 Test of key joints strength

8.1 Worm Wheel

8.2 Chain Drive Asterisk

8.3 Driven Chain Transmission Asterisk

9 Gearbox housing structural dimensions

10 Calculation of reactions in supports

10.1 1st shaft

10.2 2nd shaft

10.3 3rd Shaft

11 Construction of moments on shafts

11.1 Calculation of moments of the 1st shaft

11.2 Periods of moments of the 1st shaft

11.3 Calculation of moments of the 2nd shaft

11.4 Periods of moments of the 2nd shaft

11.5 Calculation of moments of the 3rd shaft

11.6 Periods of moments of the 3rd shaft

12 Durability check of bearings

12.1 1st shaft

12.2 2nd shaft

12.3 3rd Shaft

13 Refined calculation of shafts

13.1 Calculation of the 1st shaft

13.2 Calculation of the 2nd shaft

14 Thermal calculation of reduction gear box

15 Choice of oil grade

16 Selection of fits

17 Gearbox assembly technology

18 Conclusion

19 List of literature used

Introduction

Mechanical engineering has a leading role among other sectors of the economy, since machines perform the main production processes. Therefore, the technical level of many industries largely determines the level of development of engineering.

Improving operational and quality indicators, reducing the time of development and implementation of new machines, improving their reliability and durability are the main tasks of machine builders. One of the areas of solving these problems is improving the design training of engineers of higher technical educational institutions.

A large opportunity for improving the work of designers is provided by the use of computers, which allows you to optimize designs, automate various parts of the design process.

The objects of course design are drives of various machines and mechanisms, using most parts and assemblies of general machine-building applications.

An important goal of the project is to develop engineering thinking, including the ability to use previous experience, find new ideas, model using analogues. The course project on the details of machines is characterized by the multivariability of decisions with the same task, which develops the students' thinking activity and initiative.

The most important task of course design is to develop the ability to develop technical documentation. Based on the initial prerequisites from the course of graphics and machine-building, in the process of independent work on the course project, students master free reading and execution of drawings of unlimited complexity.

Gearbox Assembly Technology

Prior to assembly, inner cavity of reducer housing is thoroughly cleaned and covered with oil-resistant paint. Assembly is performed in accordance with drawing of general view of reduction gear box, starting from shaft assemblies.

Keys are laid on shafts and gearbox gear elements are pressed. The retaining rings and bearings should be fitted, pre-heated in oil up to 80100 degrees Celsius, in series with the transmission elements. The assembled shafts are laid in the base of the reduction gear case and put on the cover of the case, covering the surfaces of the joint of the cover and the case with alcohol varnish. For alignment, a cover is installed on the body using two conical pins; bolts that attach the cover to the housing are tightened. After that, lubricant is put into bearing chambers, bearing covers with set of metal gaskets are installed, heat gap is adjusted. Prior to installation of through covers felt seals impregnated with hot oil are put into grooves. By turning the shafts there is no jamming of bearings (the shafts must be rotated by hand) and the cover is fixed with screws. Then plug of oil discharge hole with gasket and iron oil indicator are screwed in. Oil is poured into the housing and the inspection hole is closed with a cover with a gasket, the cover is bolted. The assembled gearbox is rolled and tested on the bench according to the program set by the specifications.

Conclusion

During the course project, the knowledge gained during the past period of study in such disciplines as: theoretical mechanics, material resistance, materials science was fixed.

The purpose of this project is to design a drive, which consists of both simple standard parts and parts, the shape and dimensions of which are determined on the basis of design, technological, economic and other standards.

In the course of solving my task, the method of selecting the drive elements was mastered, design skills were obtained to ensure the necessary technical level, reliability and long service life of the mechanism.

The experience and skills gained during the course project will be required in the execution of both course projects and the diploma project.

It can be noted that the designed reduction gear has good properties in all respects.

Based on the results of calculation for contact endurance, the effective stresses in engagement are less than the permissible stresses.

Based on the results of the calculation of bending stresses, the actual bending stresses are less than the permissible stresses.

The calculation of the shaft showed that the safety margin is more than permissible.

Required dynamic lifting capacity of rolling bearings is less than passport capacity.

When calculating, an electric motor was selected that meets the specified requirements.