Belt conveyor drive with two-stage cylindrical reduction gear

Contents

1 Design Assignment

2 Introduction

3 Kinematic calculation of the drive and selection of the electric motor

3.1Define the service life of the drive device

3.2Selecting an electric motor and determining the required power on the operating link of the drive

3.3Defining the gear ratio of the drive

3.4Power and kinematic parameters of drive shafts

4 Calculation of gears

4.1 Calculation of cylindrical spur gear

4.2 Calculation of cylindrical helical transmission

4.3 Calculation of chain transmission

5 Determination of loads of gear box shafts

6 Design calculation of gear box shafts

7 Gear and Wheel Design Dimensions

8 Gearbox housing structural dimensions

9 First stage of gearbox arrangement

10 Serviceability check of bearings

11 Test of key joints strength

12 Check calculation of shafts

13 Selection of couplings

14 Landing of gears and bearings

15 Choice of oil grade

16 Gearbox Assembly Description

List of literature used

Introduction

The object of the course design is a belt conveyor drive with a cylindrical two-stage coaxial reduction gear with a bifurcated high-speed stage.

A reduction gear is a mechanism made in the form of a separate unit, which serves to reduce the angular speed and, accordingly, increase torques. The gearbox is an integral part of modern equipment. In general-purpose drives developed during course design, the reduction gear is the main and most labor-intensive unit.

The arrangement of the engagement gears in a separate closed housing guarantees sufficient mounting accuracy, good lubrication and correspondingly high efficiency, less wear and tear, as well as reliable protection of the gears from environmental influences. Gearboxes of various types with a constant gear ratio are widely used in all sectors of the economy. The most common are gearboxes, which consist of cylindrical gears.

The coaxial circuit allows to obtain smaller dimensions along the length; this is its main advantage. In coaxial gears, the high-speed stage is often underloaded, since the forces arising in the engagement of the wheels of the slow-speed stage are much larger than the high-speed stage, and the inter-axial distance of the stages is the same. This is one of the main drawbacks of coaxial gearboxes. In addition, their disadvantages include the difficulty of lubricating bearings located in the upper part of the housing and the large distance between the supports of the intermediate shaft.

Obviously, the use of coaxial gears is limited to cases where it is not necessary to have 2 output ends of a high-speed or slow-speed shaft, and the coincidence of the geometric axes of the input and output shafts is convenient with the intended general arrangement of the drive .

Motor selection and motor kinematic calculation

3.1. Determination of the service life of the drive device:

Service life L = 365· L· K· t· L· K, where

L - service life of the drive (years)

K - annual usage factor

t - shift duration

L - number of shifts

K - replaceable utilization factor

L = 365· 8· 0, 8· 8· 2· 0.33 = 12334 h

Take down time of the machine unit 15% of the resource. Then

L = 12334· 0.85 = 10483.9 h.

First stage of gearbox arrangement

The layout drawing is made in one projection.

Draw wheels and gears. We determine the location of the ball bearings, the distance between the ends of the rotating parts and the wall of the housing is taken equal to 10 mm. Then, outline of inner wall and partition serving to support ends of high-speed and slow-speed shafts is outlined. We determine the thickness of the partition, after which we arrange the gear and wheel so that the distance between the wheel and the partition is equal to 10 mm. Finally outline the inner wall of the reduction gear box .

We pre-assign bearings of light and particularly light series, we choose the dimensions of the bearings according to the diameter of the shaft at the place where the bearings fit:

For all shafts we accept radial bearings.

dp1 = 45 mm;

dp2 = 50 mm;

dp3 = 70 mm

According to table K27 [1, p. 432] we have:

For high-speed shaft

Bearing No. 209: d = 45 mm; D = 85 mm; B = 19 mm; r = 2 mm; Cr = 33.2 kN; C0 = 18.6 kN;

For intermediate shaft

Bearing No. 210: d = 50 mm; D = 90 mm; B = 20 mm; r = 2 mm; Cr = 35.1 kN; C0 = 19.8 kN;

For slow-moving shaft

Bearing No. 214: d = 70 mm; D = 125 mm; B = 24 mm; r = 2.5 mm; Cr = 61.8 kN; C0 = 37.5 kN;

Gearbox assembly

Assembly is performed in accordance with gearbox assembly drawing, starting from shaft assemblies. All bearings and wheels are heated to 80100 before installation on the shaft

Oil breaking rings and bearings are installed on the input shaft. Cuffs are installed before placing through covers.

On the output shaft we install a key, a gear wheel, distance rings, bearings. Cuffs are installed before placing through covers. Then input and output shafts are installed in lower part of housing.

Then the plane of the housing base connector is covered with a thin layer of UT34 sealing compound and the middle part of the housing is installed on it and bolted to it. Lugs at bearing units are connected with screws.

On the intermediate shaft we install a key, a gear wheel, a remote ring and bearings. Then blind covers are installed. The intermediate shaft is installed in the middle part of the gear box housing. The plane of the middle part connector with the reducer cover is covered with a thin layer of UT34 sealant. Then reduction gear cover is installed and connected with middle part of housing by bolts. Lugs at bearing units are connected with screws.

Further, keys are laid on ends of inlet and outlet shafts. A half-coupling is installed on the input shaft for connection to the engine shaft. Chain drive star is installed on output shaft. Oil discharge hole plugs and perfume plug are screwed in.

Then oil is poured.

The assembled gearbox is rolled and checked on the bench according to the program set by the specifications.