Course work in the discipline "Machine parts" on the topic "Design of the belt conveyor drive"

Contents

Summary

1. Purpose and application of the drive

2. Technical characteristics of the drive

2.1 Determination of overall drive efficiency

2.2 Determination of shaft power, speed and torque

3. Description and justification of the assigned kinematic diagram

4. Calculations confirming operability and reliability

4.1. Defining Shaft Diameters

4.2 Bearing Selection

4.3 Check of bearings of the most loaded shaft by dynamic lifting capacity

4.4. Gearbox design dimensions

4.5. Key Connection Selection and Calculation

4.6. Selection of gears and bearings fits

4.7. Lubrication of gears and bearings

4.8. Check calculation of low-speed shaft (most loaded) for fatigue strength and endurance

4.9. Calculation of chain transmission

5. Description of organization of works using the developed drive

6. Standard products used in drive design

Conclusion

List of literature

Application

Summary

The purpose of the course project is to design a belt conveyor drive, consisting of an asynchronous general-use electric motor, a conical reduction gear, a drive shaft, a chain transmission, an elastic coupling with a torus-shaped shell. The drive should be designed in accordance with the following technical condition: power supply from the AC three-phase current network with a frequency of 50 Hz and a voltage of 380V, typical loading and operation mode - IV, design life of 13000 hours, version of heat treatment of the teeth of the reduction gear box III, mass production.

Course Project Tasks:

Develop a general view of the drive (at the design stage);

Perform kinematic calculations, determine torque on shafts and shaft diameters, make design diagrams, calculate key joints and rolling bearings.

Develop gearbox (at the technical design stage);

Develop detailed drawings of two parts;

Develop coupling assembly drawing;

Develop drive shaft (at technical design stage).

In this work, the belt conveyor drive is designed to transmit rotational motion from the motor to the drive shaft of the belt assembly conveyor. Belt conveyors are used to move bulk loads over short, medium and long distances in all areas of modern industrial and agricultural production

The operation of the drive begins with the fact that the electric motor is connected to the high-speed shaft of the reduction gear by an elastic clutch with a torus-shaped shell for transmitting torque, then the torque is transmitted to the slow-moving shaft, and from it through a chain drive to the drive shaft of the belt conveyor.

Selection of gears and bearings fits

The CMEA standard recommends the use of mainly wheel fits in the hole and gear system in the shaft system. The use of a hole system is preferable because it reduces the range of expensive tools. The shaft system is used in case of technological expediency of using smooth shafts coupled with parts having different limit deviations.

Internal bearing ring tolerance field is selected as per GOST 52071. Since in the reduction gear the inner rings of bearings of all shafts are rotated and the outer rings are in place, local loading takes place, therefore the bearing is mounted with a gap, which allows to reduce the wear of the inner tracks.

According to the recommendations of GOST 332585, we accept the following bearing fits:

- for external rings -;

- for inner rings - g6.

To install the key in the shaft slot, use the recommended PT CMEA 5773 adapter fit P9/h9, and to install the gear attachment keys, use the clearance fit H7/r6, respectively.

The tolerance of the shaft for cuffs is d9.

Bearing cover is installed with H7/d11 fit.

The cup is installed with landing - H7/js6.

Toothed rim is installed on hub with landing - H7/js6.

Description of organization of works using the developed drive

Reduction gear box. Prior to assembly, inner cavity of housing is thoroughly cleaned and covered with oil-resistant paint. The gearbox is assembled in accordance with the general view drawing. Assembly is started with tapered roller bearings being put on the shaft-gear. Assembled shaft-gear is inserted into sleeve and then into housing. Then roller conical bearings are installed on shaft of conical gear wheel, key is laid and wheel is pressed until stop against spacer bushing. The shaft assembly is inserted into the housing. Then upper part of body - cover is screwed in. Rubber cuffs are put into screwed through covers and installed in housing with gaskets. To adjust the engagement, it is necessary to shift the entire set of shaft with the wheel in the axial direction until the middle plane of the wheel coincides with the axis of the gear. This is achieved by transferring a part of the gaskets from one side of the body to another.

Clutch. The design of the developed drive used an elastic coupling with a torus-shaped shell. It was chosen because it is designed to transfer rotation between mechanisms that are subjected to significant vibration, impact and dynamic loads. The presented type of couplings perfectly compensates for the radial displacement of the shafts up to (4.5 mm). The advantages of such couplings also include high damping properties, simplicity of construction and a long operating period of up to 10 years. The tasks of the coupling are to provide electro and noise insulation of the drive units. This is an effective solution for mechanisms in which it is difficult to ensure shaft alignment under impact and variable loads. A huge advantage of a coupling with a torus-shaped shell is the ability to quickly replace the elastic element without the need to dismantle the coupling. During installation of the coupling on both sides half-rings 1 are brought inside the shell and fixed with rings 3 and screws 8. Then one half-coupling installed on the shaft is shifted in axial direction, and the assembled shell assembly is installed between half-couplings and filled under projections of flanges 4. Half-coupling is shifted in reverse direction, shell 2 is fixed by bolts 7 tightening flanges of half-couplings with half-rings.

Conclusion

In the course design, a belt conveyor drive is designed, consisting of an electric motor, a reduction gear, a drive shaft, a chain gear, and a coupling .

The following are presented in the work:

General view of the drive (at the sketched design stage);

Gearbox (at the technical design stage);

Working drawings of two parts;

Coupling assembly drawing;

Drive shaft (at engineering stage).

All drive elements are mounted on a frame welded from structural steel.

The operation of the drive begins with the fact that the motor AIRX160S8, connected to the high-speed shaft of the reduction gear box by means of an elastic coupling with a torus-shaped shell, transmits torque. Then torque is transmitted from slow-moving shaft through chain drive to drive shaft and further to belt conveyor.

The main calculations were made in the course design, the optimal design was chosen. Calculations and parameter selection are described in this explanatory note. The graphic part of the project is presented on 4 sheets of A1 format, 2 sheets of A3 format, and 1 sheet of A2 format, and contains a calculation explanatory note and all necessary specifications.