Редуктор. Курсовой проект. Детали машин.

Contents

Contents

1. Introduction

2. Motor selection and kinematic calculation

3. Determination of capacities and transmitted torques on shafts

4. Calculation of gears

4.1 Calculation of conical gear with circular tooth of high-speed step of reduction gear box

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

4.3 Calculation of chain transmission

5. Preliminary calculation of shaft diameters

6. Selection and verification calculation of couplings

7. Preselection of bearings

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

9. Calculation of shafts by equivalent moment

9.1 Calculation of driving shaft

9.2 Calculation of intermediate shaft

9.3 Calculation of driven shaft

10. Selection of bearings by dynamic lifting capacity

10.1 Calculation of driving shaft bearings

10.2 Calculation of intermediate shaft bearings

10.3 Calculation of driven shaft bearings

11 Selection and check calculation of key connections

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

13. Calculation of shafts for endurance

13.1 Calculation of drive shaft

13.2 Calculation of intermediate shaft

13.3 Calculation of driven shaft

14. Gearbox Assembly Description

15. Adjustment of bearings in engagement

Literature

Computer Calculation

Specification

1. 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 that the use of high-speed downshift engines instead of a slow-speed engine without transmission is economically feasible. 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 conical cylindrical reduction gear is developed, the cylindrical stage is bifurcated.

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 a predetermined position of the shaft rotation axis. This drive utilizes roller radial thrust and ball radial bearings which receive radial and axial loads in conical and cylindrical gears.

Gearbox Assembly Description

Prior to assembly, inner cavity of reducer housing is thoroughly cleaned and covered with oil-resistant paint. Assembly is carried out in accordance with the general view drawing of the reduction gear box, starting from the shaft assemblies:

on the high-speed shaft-gear of position 2, the bearings of position 32 are fitted through the bushing of position 25 preheated in oil to 80100 ° C, after which the assembled unit is placed in the sleeve of position 5;

- in the intermediate shaft-gear of the position 23, the keys of the positions 38 and 39 are inserted and the gear wheel of the position 24 and the gear wheel of the position 7 are pressed through the distance sleeve of the position 6, and then the bearings of the position 33 heated previously in oil are installed;

- a key of position 40 is placed in the slow-moving shaft of position 12 and gear wheels of positions 13 and 16, bearings of position 34, heated previously in oil, are installed.

The assembled shafts are laid in the base of the housing of the reduction gear box of position 1 and put on the cover of the housing, covering previously the surfaces of the joint of the cover and the housing with alcohol varnish. Conical pins are used to base the cover relative to the body. After that bearing covers are installed. By turning the shafts there is no jamming of bearings (the shafts must be rotated by hand) and the covers are fixed with screws.

Then plug of oil discharge hole with gasket and oil indicator are screwed in. Oil is poured into the housing and the inspection hole is closed with a cover with a paperboard gasket; cover is bolted.

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

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