Design of lifting mechanism

Contents

Introduction

1. Energy - kinematic calculation of the drive

1.1 Selection of electric motor

1.2 Determination of rotation speeds and torques on shafts

2 Gearbox transmission calculation

2.1 Selection of materials, heat treatment and determination of permissible stresses for transmission

2.2 Gearbox transmission design calculation

2.3 Transmission check calculations

2.3.1 Check calculation of transmission by contact voltages

2.3.2 Check calculation of transmission by bending stresses

2.3.3 Thermal calculation

3 Calculation of worm gear using computers

4 Calculation of drive shafts

4.1 Design calculation of all drive shafts

4.2 Check calculation of low-speed gear box shaft for fatigue endurance

5 Selection of bearings for all drive shafts

5.1 Preselection of bearings for all drive shafts

5.2 Check calculation of driven shaft rolling bearings

gearbox for dynamic load capacity

6 Calculation of key connections

7 Selection and calculation of couplings

8 Lubrication of reduction gear box and drive units

9 Project safety and environmental friendliness

Conclusion

List of sources used

Appendix A

Appendix B

Appendix B

Appendix D

Appendix D

Introduction

A design engineer is the creator of a new technique, and the level of his creative work is more determined by the pace of scientific and technological progress. The activity of the designer is one of the most complex manifestations of the human mind. The decisive role of success in creating a new technique is determined by what is embedded in the design drawing. With the development of science and technology, problematic issues are solved taking into account the increasing number of factors based on the data of various sciences. The project uses mathematical models based on theoretical and experimental studies related to volume and contact strength, materials science, heat engineering, hydraulics, the theory of elasticity, and construction mechanics. Information from material resistance courses, theoretical mechanics, machine-building drawing, etc. is widely used. All this contributes to the development of independence and a creative approach to the problems posed.

Currently, the Republic of Belarus does not have its own production of gearboxes for general use. Meanwhile, the republic has a number of developments that would allow the organization of such production.

When choosing the type of gearbox for the actuator, it is necessary to take into account many factors, the most important of which are: the value and nature of the load change, the required durability, reliability, efficiency, weight and overall dimensions, noise level requirements, product cost, operating costs.

Of all types of gears, gears have the smallest dimensions, weight, cost and friction losses. The loss factor of a single gear pair with careful execution and proper lubrication does not usually exceed 0.01. Gear gears in comparison with other mechanical gears have great reliability in operation, constant gear ratio due to lack of slippage, and can be used in a wide range of speeds and gear ratios. These properties provided a large distribution of gears; they are used for capacities ranging from negligible (in instruments) to measured in tens of thousands of kilowatts. The transmitted moments reach 5,106 Nm. Wheel diameters, for example, in gears on the propeller of ship's installations, reach 6 m.

The disadvantages of gears may include high manufacturing accuracy requirements and high speed noise.

One of the goals of the project is to develop engineering thinking, including the ability to use previous experience, model using analogues.

For the course project, objects are preferred, which are not only well distributed and of great practical importance, but also are not subject to moral aging in the foreseeable future.

There are various types of mechanical gears: cylindrical and conical, with straight teeth and oblique, hypoid, worm, globoid, one- and multithreaded, etc. This raises the question of choosing the most rational transmission option. When choosing the type of transmission, they are guided by indicators, among which the main ones are efficiency, overall dimensions, weight, smoothness of operation and vibration loading, technological requirements, the preferred number of products.

When choosing the types of gears, type of engagement, mechanical characteristics of materials, it should be borne in mind that material costs account for a significant part of the cost of the product: in general-purpose gears - 85%, in road cars - 75%, in cars - 10%, etc.

Finding ways to reduce the mass of designed objects is an essential prerequisite for further progress, a prerequisite for saving natural resources. Most of the energy currently generated is from mechanical transmissions, so their efficiency to a certain extent determines operating costs.

The most complete requirement for weight reduction and overall dimensions is satisfied by the drive using an electric motor and a reduction gear with external engagement.

Calculation of worm gear using computers

The rapid development of computer technology and information technology made it possible to automate calculations that previously took a long time, which made it possible to reduce the cost of time and labor, as well as prevent the possibility of human error. All this leads to an increase in the quality and competitive ability of products.

This program is written in Mathcad, which is based on sequential computational programming technology, the essence of which is that the development environment takes on the calculation of the criterion of operability, strength and serviceability of transmission under load at the required life of the reduction gear box.

Calculation of worm gear using computers - Appendix B.

Conclusion

During the course project on "Machine Parts," the knowledge gained over the past period of training in such disciplines as: theoretical mechanics, material resistance, materials science was fixed.

The purpose of this project was to design the drive of the lifting mechanism, which consists of an electric motor, a worm reduction gear, a drive shaft with a drum and a toothed clutch, and an elastic clutch.

In the course of solving the problem set in front of me, the skills of designing a worm gear were obtained, which allows to ensure the necessary technical level, reliability and long service life of the mechanism, calculation of keys, selection of bearings and couplings. The 4A112MA8U3 electric motor was chosen.