Belt Conveyor Drive - Drawings, Calculation

Contents

Table1 page

Enter 2 page

Assignment for course project2 pp

Brief description of the main mechanism.. 2 pages

Initial data for calculation 3-4 pages

Technical requirements. 4 pages

1. Motor selection and kinematic calculation.. 4-6 pp

2. Calculation of cylindrical gear gear6-13 pp

3. Calculation of V-belt transmission 14-18 pp

4. Preliminary calculation of gross 18-19 pp

5. Selection and durability check of bearings... 19-26 pp

6. Updated gross calculation 26-30 pp

7. Check of key and spline joints strength.. 31-32 pp

8. Design of drive shaft with drum 33-37 pp

9. Selection of reduction gear box and bearings lubrication.. 38 pts

10. Coupling select.39-40 pp

11. Selection of fits of main parts of reducer 41 pts

12. Gearbox assembly 41 pts

13. Assembly of drive 42 pps

14. Safety Technician 42 pp

List of literature used. 43 pages

Introduction

In this course design, a belt conveyor drive was developed: an assembly drawing of the driving shaft was developed, a motor, a reduction gear box and a clutch were selected. Reduction gear consists of cast cast iron housing accommodating transmission elements. Input shaft is connected by means of belt transmission to motor output by means of splined connection with conveyor.

A reducer is a mechanism 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. 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.

As a motor, most conveyors use a standard three-phase current electric motor. The transfer mechanism, depending on the task for the course design, may contain an open gear and a reduction gear or one reduction gear.

The actuator (IM) in this design is the conveyor drive shaft. For a belt conveyor, it is a shaft of a drive drum, and for a chain conveyor, it is a shaft with one or two drive sprockets. According to the received task, the conveyor drive was designed, that is, calculations were made and drawings were developed in the scope established by the task for the course design. All necessary calculations and explanations of the features of the design and operation of the drive are in the form of an explanatory note.

Job for Course Project

Design belt conveyor drive consisting of asynchronous motor (1), V-belt transmission (4), suspended single-stage reduction gear (3) with reactive rod (5), as well as drive shaft with drum (2).

Selection of gear box and bearings lubrication

To reduce friction power losses, reduce the intensity of wear of friction surfaces, their cooling and cleaning from wear products, as well as to protect against jamming, gouging, corrosion, reliable lubrication of surfaces must be provided.

In mechanical engineering, the so-called crankcase system is widely used for lubricating gears, that is, the immersion of a moving wheel in an oil bath with liquid lubricant according to GOST 2079975. The lubricant must be liquid so that it is sprayed in the body and an oil mist is formed there, which is necessary for continuous lubrication of all friction parts of the mechanical transmission .

The choice of lubricant is based on the experience of the machines.

Oil grade assignment principle: the higher the wheel circumferential speed, the lower the oil viscosity and the higher the engagement contact stresses, the greater the oil viscosity. Therefore, the required viscosity of the oil is determined depending on the contact voltage and the circumferential speed of the wheels.

At a circumferential speed of up to 2 m/s and contact voltages αH = 6001000 MPa, the recommended kinematic viscosity of oil is 60 mm ²/s. For reducer we accept oil I-G-A-68 as per GOST 2079988 .

Bearings in this design version of shafts supports of cylindrical reduction gears are lubricated with plastic lubricant laid in assembly. This is due to the fact that in this case, the value of the circumferential speed of the wheels (V < 3 m/s) does not allow to reliably lubricate these bearings with condensate of oil mist formed when oil is sprayed from the oil bath of the crankcase, the wheels of the reduction gear are immersed in it.

Plastic (ointment-like) lubricants are liquid oils thickened with special thickeners with the inclusion of various additives.

The main plastic lubricants used in the bearing assemblies of general-purpose reducers are currently Litol-24 TU 2115075 (for operation in the temperature range - 40... + 130C) and TSIATIM-201 GOST 626774 (-60... + 90C).

Applicable in our case Litol-24 TU 2115075.

10. Selection of coupling

Couplings are designed for longitudinal connection of rotating shafts and transmission of torque (for some couplings it is also possible to perform a number of additional functions, for example, compensation of axial, radial or angular displacements).

The main parameters when selecting the coupling are: nominal diameters of the shafts to be connected, design torque, speed and operating conditions.

In practice, the following formula is used to determine the calculated torque Tp:

;

where Cr is the overload factor, which takes into account the mode of operation and responsibility of the structure, T- torque on the corresponding shaft, Tnom is the nominal torque indicated in the catalog.

Kr values are accepted for belt conveyors - 1.25... 1.5, chain conveyors, screw conveyors, scrapers - 1.5... 2.0; blowers and fans - 1.25... 1.5; centrifugal pumps - 1.5... 2.0; piston pumps and compressors - 2.0... 3.0; metal cutting machines: with continuous movement 125.. 1.5, with reciprocating motion - 1.5... 2.5; woodworking machines - 1.5... 2.0; ball mills, crushers, hammers, scissors 2.0... 3.0; cranes, elevators - 3.0... 4.0.

To connect the output ends of the engine and the high-speed shaft of the reduction gear (usually located on a common frame), elastic sleeve-and-sleeve couplings and couplings with a sprocket are used. They have small sizes and mass, good elastic properties and a minimum fly moment, which reduces the starting loads on the shafts to be connected.

Chain couplings and couplings with torus-shaped shell are used to connect output ends of slow-moving shaft of drive shaft reduction gear. These couplings are able to compensate for the significant misalignment of the shafts. The size of the coupling is not of practical importance here, since the flyover moment brought to the engine shaft decreases by an equal number of times to the square of the gear ratio. Standard couplings are available of two types: with cylindrical and conical mounting holes (except for a coupling with an asterisk, it has only a cylindrical mounting hole), and each type has two versions - for long and short shaft ends. It is possible to use half-couplings with different diameters of mounting holes when transmitting the same torque.

11. Selection of fits of main parts of reduction gear box

The selection of mounts on the shaft of the inner rings of the rolling bearings is made in accordance with GOST 3325 85, depending on the accuracy class of the bearings, their operating modes and the type of loading of the bearing rings.

Bearings operate in low load mode (moderate push operation) or medium loads under conditions of frequent re-installation. When the shaft is rotated, the inner race of the rolling bearing (when the outer bearing is stationary) is subjected to circulation loading. In this case, it is installed with interference on the shaft, since when the circulating loaded ring is installed with a gap, such a ring inevitably slips along the shaft, which leads to soaking and wear of the contacting surfaces. Depending on the mode of operation and the accuracy class of the bearing, we select the fit on the shaft of the internal rings of the rolling bearings k6.

At moderate loading (cr 15 MPa) and non-revertive operation, fits are used: H6/k5; H7 / k6; H8 / k7.

The tolerance field for the width "b" of the key slot in the shaft intended for the prismatic key is selected according to GOST 23360-78 depending on the nature of the key connection and the type of load transmitted to it. For fixed connection of key with shaft at constant loading field of tolerance for width of shaft slot is assigned according to N9.

The bearing covers of the high-speed and slow-speed assembly are installed as per fit H7.

12. Gearbox assembly

The assembled shafts are laid in the base of the reduction gear case and put on the cover of the case, covering the movable surface of the joint of the cover and the case with butt oil.

Key is installed on driven shaft, gear wheel is put on, lubricant is laid in bearing chambers, bearing covers are placed.

Key is installed on drive shaft.

Oil outlet plug with gasket and oil indicator are screwed in, oil is poured into housing, cover is installed and bolted.

The assembled gearbox is rolled and tested on a bench.

13. Drive Assembly

It is recommended to assemble the belt conveyor drive as follows:

1. Drive shaft (1) is installed on the frame and attached to it by means of bolts.

2. Reduction gear (2) is fitted on input end of drive shaft (1).

3.Electromotor (8) is bolted to plate with tensioner (4).

4.The driving pulley of the V-belt transmission (6) is put on the output shaft of the electric motor (8).

Driven pulley (7) is fixed on high-speed shaft of reduction gear (2).

5. Reduction gear (2) is set to operating position by means of reactive rod (5), which provides stability of structure.