Design of Chain Conveyor Drive

Contents

Introduction

1. Selection of electric motor

2. Kinematic calculation

3. Gearbox calculation

3.1 Calculation of high-speed stage

3.2 Calculation of slow-moving stage

4. Calculation of chain transmission

5. Calculation of housing elements

6. Bearing calculation

7. Check calculation of shafts for fatigue strength

8. Calculation of Keyway Connection

9. Selection of couplings

10. Oil selection

11. Gearbox assembly

Conclusion

List of literature used

Application

Introduction

The purpose of the course project is to design the drive of a chain conveyor, including: electric motor; two-stage cylindrical reduction gear - mechanism consisting of gear cylindrical gears, which serves for transmission of motion from engine to working member with reduction of rotation speed and increase of torque and chain transmission.

Drive units are mounted on welded frame.

Industrial oil I - 50A is used to lubricate friction surfaces of reduction gear parts, gear wheels are lubricated by immersion in bath with liquid lubricant in lower part of reduction gear case by crankcase method. Other units and parts, including rolling bearings, are lubricated due to oil spraying by submerged wheels and circulation of formed oil mist inside the housing.

Sealing devices are used to prevent the lubricant from flowing out of the gearbox body or taking it out in the form of oil mist and splashes, as well as to protect them from dust and moisture ingress from the outside.

To protect the drive, a safety clutch is used.

10 Oil selection

Lubrication of gear engagement and rolling bearings is performed by oil poured inside the gearbox housing up to the level ensuring the gear wheel immersion by approximately 10 mm. The volume of the oil bath is determined on the basis of 0.25 dm3 per 1 kW of transmitted power:

V = 0.25· 4 = 1 dm3 = 1 l, (65)

Set the viscosity of the oil. At contact stresses H = 693 MPa and speed v = 2.5 m/s, the recommended kinematic viscosity of the oil should be approximately equal to 50· 106 m2/s.

We choose industrial oil I - 50A, with kinematic viscosity (47... 55)· 106 m2/s according to GOST 2079975.

11 Gearbox assembly

The gearbox is assembled in the following sequence:

Install the gearbox housing on the bench (using crane beam or manually).

Manually install a pre-assembled high-speed shaft (i.e. bearings are pressed on the shaft) into the reduction gear sockets.

Manually install a pre-assembled intermediate shaft in the reduction gear sockets (i.e. bearings are pressed on the shaft, a cylindrical wheel is fixed by a key). At this stage, conical engagement is assumed.

Manually install a pre-assembled slow-moving shaft in the gearbox sockets (i.e. a gear wheel is fixed on the shaft by means of a key, sleeves are dressed and bearings are pressed). At this stage, gear engagement is assumed.

Install the gearbox cover using the crane beam.

Mark 2 holes for pins (ruler, caliper).

Drill 2 holes for pins (electric drill).

Stitch (hammer).

Attach the inspection window.

Install two blind bearing covers.

Install two through bearing covers assembled (i.e. cuffs are fitted in the covers).

Install key under half-coupling (hammer).

Install key under sprocket (hammer).

Pour over the oil.

Then check the wheel rotation by hand, check the run-out of the output shaft. Bolted connections should also be monitored during tightening. Perform leak check.

Conclusion

In mechanical engineering, reducers, mechanisms consisting of gear or worm gears made in the form of a separate unit and serving to transfer power from the engine to the working machine are widely used. The kinematic drive circuit may include, in addition to the gearbox, open gears, chain or belt gear.

The purpose of the reduction gear is to reduce the angular speed and increase the torque of the driven shaft compared to the driving shaft. Mechanisms for increasing angular velocity are made in the form of separate units, called multipliers.

Structurally, the reduction gear consists of a housing (cast, cast iron or welded steel), in which the transmission elements are placed - gears, shafts, bearings, etc.

The reduction gear is designed either to drive a certain machine, or to a given load (torque on the output shaft) and gear ratio without specifying a specific purpose.

The drive is supposed to be located in a closed, heated, ventilated room equipped with a three-phase AC supply.

The drive to the horizontal shaft consists of a cylindrical reduction gear, the high-speed shaft of which is connected to the engine by an elastic bushing-flange clutch.

In carrying out this course project, I have acquired the skills to develop comprehensive technical documentation containing calculations, drawings, explanatory notes and other materials necessary for the production of the machine. I got acquainted with the rules of design and design of projects standardized in the unified system of design documentation (ESKD).