Belt Conveyor Drive Development - Machine Parts

Contents

Introduction

1 Motor selection and kinematic calculation of the drive

2 Determination of power and transmitted torques

3 Calculation of gears

3.1 Calculation of cylindrical spur gear of low-speed stage of reduction gear box

3.1.1 Selection of gear material

3.1.2 Determination of equivalent number of voltage change cycles

3.1.3 Definition of allowable contact stresses

3.1.4 Definition of permissible bending stresses

3.1.5 Permissible stresses to check the strength of teeth during G-loads

3.1.6 Calculation of geometric parameters of transmission

3.1.7 Forces in engagement

3.1.8 Endurance test for contact stresses

3.1.9 Endurance test for bending stresses

3.1.10 Endurance check at G-loads

3.2 Calculation of cylindrical spur gear of high-speed stage of reduction gear box

3.2.1 Selection of Gear Material

3.2.2 Determination of equivalent number of voltage change cycles

3.2.3 Definition of allowable contact stresses

3.2.4 Definition of permissible bending stresses

3.2.5 Allowable stresses for check of teeth strength during G-loads

3.2.6 Calculation of geometric parameters of transmission

3.2.7 Forces in engagement

3.2.8 Endurance test for contact stresses

3.2.9 Test calculation for endurance by bending stresses

3.2.10 Endurance check at G-loads

3.3 Calculation of chain transmission

4 Preliminary calculation of shaft diameters

5 Selection and check calculation of couplings

6 Preselection of bearings

7 Layout diagram and selection of lubrication method of gears and bearings, sizing of housing parts

8 Calculation of shafts by equivalent moment

8.1 Drive shaft

8.2 Intermediate shaft

8.3 Driven shaft

9 Selection of bearings by dynamic lifting capacity

9.1 Calculation of driving shaft bearings

9.2 Calculation of intermediate shaft bearings

9.3 Calculation of driven shaft bearings

10 Selection and check calculation of key connections

10.1 Calculation procedure

10.2 Key under clutch

10.3 Key under high-speed wheel

10.4 Key under low-speed gear wheel

10.5 Key under sprocket

11 Calculation of shafts for endurance

11.1 Calculation of driving shaft

11.2 Calculation of intermediate shaft

11.3 Calculation of driven shaft

12 Assignment of fits, surface roughness, selection of degrees of accuracy, and assignment of feature control frame tolerances

13 Gearbox assembly

14 Adjustment of bearings and engagement

15 Description of the wiring diagram. Assembly and adjustment of the drive

Literature

Introduction

A reduction gear is a mechanism consisting of gear or worm gears, made in the form of a separate element and serving to transfer rotation from the shaft of the engine to the shaft of the working machine.

The purpose of the reduction gear is to reduce the angular speed and increase the torque of the driven shaft compared to the driving one.

The use of gearboxes is due to economic considerations. The mass and cost of the engine at the same power decrease with an increase in its speed. It turns out to be economically feasible to use high-speed downshift engines, instead of a slow-moving engine without transmission. Asynchronous motors with a frequency of 750 and 1500 rpm are most widely used.

The reduction gear consists of a housing in which transmission elements are placed - gears, shafts, bearings, etc.

Gearboxes are classified according to the following main features: gear type (toothed, worm or gear-worm); number of stages (single-stage, two-stage, etc.); type of gears (cylindrical, conical, etc.); relative location of shafts in space (horizontal, vertical); peculiarities of kinematic scheme (unfolded, coaxial, with bifurcated stage, etc.). In this design, a toothed two-stage cylindrical coaxial reduction gear is being developed.

Gears are the main type of gears in machine building. Their main advantages: high load capacity, and, as a result, small dimensions; high durability and reliability of operation; high efficiency; constant transmission ratio; possibility of application in a wide range of powers, speeds, transfer ratios. Disadvantages: noise during operation, inability to continuously change the gear ratio, insecurity during overloads, the possibility of significant dynamic loads due to vibration.

Bearings serve as supports for shafts. They receive radial and axial loads applied to the shaft and maintain the specified position of the shaft rotation axis. This drive utilizes ball radial thrust and ball radial bearings which receive radial and axial loads in cylindrical gears.

Gearbox assembly

The reduction gear is assembled in accordance with the assembly drawing.

To allow location and shape of mounting holes for bearings, during manufacture cover of high-speed stage is installed on pins and boring of mounting holes for bearings is performed. The same is done when the gearbox cover is installed.

The gearbox is assembled in the following sequence: bearings are installed on the drive shaft. Install the assembled shaft in the seats of the gear box housing and close the outlet ends of the shafts with covers.

Assembly of intermediate shaft is performed as follows: safety clutch is installed in assembly, gear wheel is fixed, bearings are installed on left and right sides, assembled unit is installed in seats of reduction gear box, and ends of shafts are closed with covers.

The driven shaft is assembled as follows: the gear wheel is fixed, with the help of a key, the bushing is fixed, bearings are put on the left and right sides, the unit is installed in the seats of the reduction gear box, and the ends of the shafts are closed with covers. Sprocket is installed on free end of shaft and fixed in axial direction.

We close the assembled reduction gear with a cover, the centering of which is carried out with the help of two pins. Install bolts in the corresponding holes, screw nuts on them and tighten them.

Reduction gear is disconnected from electric motor for transportation by removing clutch and circuit. The lift is then transported to the desired location. In this case, it is necessary to use the eyes provided for this in the gearbox cover (in order to avoid accidents).

Adjustment of bearings and hooks

To adjust the gear engagement, a set of adjusting gaskets is provided between the flanges and the housing and the gearbox cover.

To begin, assemble all gear shaft assemblies. Install them in the base of the housing. Put the housing cover on the base. Install bearing covers with gasket sets.

Next, you should check the rotatability of the shafts. They must rotate without knocking and jamming. If necessary, move a number of gaskets from under one bearing cover under the opposite one.

Having achieved the required smoothness of rotation of the shafts, it is necessary to remove the cover of the housing and paint all the teeth of the larger wheel of the first stage with special paint. The housing cover and bearing covers must then be put on. Further, it is necessary to turn the input shaft of the reduction gear so that the larger wheel of the first stage makes a complete revolution. Now check the contact spot on the smaller wheel of the first stage. It should be at least 50%.

Ball bearings are not adjusted.