Design of Chain Assembly Conveyor Drive

Maintaining

The Machine Parts course focuses on the calculation and design of parts, joints, and assemblies. During the design process, the engineer solves a number of complex and diverse technological tasks. The main task is to create machines that meet the needs of the national economy, give the greatest economic effect and have high technical, economic and operational indicators. The main requirements for the designed machine are high reliability, repairability, processability, minimum dimensions and weight, ease of operation. This project is run using a computer. Computer-based design reduces the labour intensity of calculations, allows you to obtain designs that are optimal in size, weight and other indicators, and provides accuracy of calculation. The role of computers will increase due to the introduction of standard units and parts in mechanical engineering. During the course project, we gain knowledge and skills to solve the above problems, as well as gain experience on computers.

1. Energy kinematic calculation of the drive on the computer

1.1 Preparation of initial data

The purpose of the energy kinematic calculation is to select an electric motor based on the required power, as well as to determine the gear ratios of all stages of the drive, based on the rotation speeds of the electric motor shaft and the shaft of the machine actuator. The data required for the initial data are summarized in Table 1.1. When the table is filled in, parameter values are taken on the basis of the following recommendations:

1) The traction force on the drive shaft of conveyor F is taken from the design specification F = 4750 N.

2) Condition designation of conveyor type - 2 (chain).

3) The symbol of the drive type is determined by its composition: only the reduction gear - 1.

4) Gearbox type symbol: cylindrical - 5.

5) Conveyor belt speed is taken from the terms of reference: V = 0.75m/s.

6) Gear hardness is assigned in accordance with the requirements of the assignment - 48HRC for both stages.

7) To determine the total efficiency of the drive, we determine the source of power loss during transmission from the electric motor to the actuator. In mechanical transmissions, power losses occur in all types of transmissions, bearings, and couplings. The total efficiency of the drive is determined by the formula:

(1.1)

In this drive, the source of loss will be: three pairs of bearings, two couplings, two cylindrical helical gears.

Note:;; ;

Substituting these values in formula (1.1), we obtain :

8) Gear ratio of open gear (electric motor - reduction gear) - 1.

9) Gear ratio of open gear (reduction gear - drive shaft) - 1.

10) The number of teeth of the traction sprocket is 7.

11) Conveyor pull sprocket pitch - 100.

1.2 Computer calculation and analysis of obtained results

The calculation results are presented in the form of table 1.2 containing initial data, values of initial parameters of motors and gear ratios of drive stages. The results of the calculation showed that the motor 4A100S2 with a speed of 2880 rpm does not allow to realize the required drive ratio.

It is advisable to choose the best option after calculating the gear gears.

6. Gearbox Sketch Layout

The design of the gearbox and other assembly units begins with sketching. Sketching is the most important step in the project. The sketch should give a detailed picture of the mutual arrangement of individual parts, assemblies, mechanisms and their interaction.

The gearbox is sketched in scale 1:1.

Before constructing the layout, we draw a horizontal axial line of the driving shaft and indicate the position of the axes of the intermediate and driven shafts, taking into account the axial distance of the shafts. Next, we plan and draw the contours of the gears. The layout diagram (Fig.6.1) is made on the basis of previous calculations with the placement of the basic dimensions necessary for the calculation of bearings on the computer.

Lubrication of gearbox elements

Lubricant is intended for reduction of friction force, reduction of wear of working surfaces, cooling of contact places.

Lubrication of the gears is carried out by dipping the gears into oil for the entire height of the tooth plus 510 mm. At contact stresses less than 600 mPa and a speed less than 5 m/s, the recommended oil viscosity should be approximately equal to m2/s. We accept I30A oil as per GOST 20799 - 75.

Bearings are lubricated by oil spraying by rotating gear wheels, and an oil mist is formed inside the housing, which covers the surfaces of all parts located inside the housing.

Conclusion

During the design process, the following tasks were solved: shafts, gears were designed. Bearings were selected, the gearbox housing was developed, on the basis of these tasks a gearbox and a chain conveyor drive were designed. Drawings of the reduction gear box, its units and parts, as well as a general view of the drive are made.

One of the means of solving the problem is computer calculation, with the help of which the main calculations are made. The drive is designed, meets the requirements of unification and standardization, as well as the requirements of economics, technology, operation, safety.

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ДАНИЛА-2.CDW

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