Course design "Calculation of single-stage cylindrical reduction gear box"

Contents

Introduction

1. Kinematic and power calculations of the drive

1.1 Electric motor selection

1.2 Total gear ratio of the drive and its breakdown by stages

2. Gearing Calculation

2.1 Selection of transmission material

2.2 Allowable stresses

2.3 Design calculation of closed cylindrical transmission

2.4 Check calculation of closed cylindrical gear train

3. Calculation of V-belt transmission

4. Developing a General Gearbox View Drawing

4.1 Selection of shaft material

4.2 Determination of geometric parameters of shafts

4.3 Preliminary selection of rolling bearings

5. Gearbox shaft design diagram

5.1 Determination of reactions in shaft bearing supports, construction of bending and torsional moments

6. Check calculation of bearings

7. Drive Design Layout

7.1 Gear Design

7.2 Selection of connections

7.3 Design of Bearing Assemblies

7.4 Gearbox Housing Design

7.5 Coupling Selection

7.6 Lubrication. Lubricating devices

8. Verification calculations

8.1 Check calculation of key

8.2 Check calculation of tightening screws of bearing units

8.3 Check calculation of shafts

Conclusion

List of literature used

Introduction

A reducer is a mechanism consisting of gears or gears, made in the form of a separate unit 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, accordingly, increase the torque of the driven shaft compared to the driving one.

The reduction gear consists of a body (cast iron or welded steel), in which the transmission elements are placed - gears, shafts, bearings, etc. In some cases, devices for lubricating hooks and bearings (for example, a coil with cooling water in the housing of the worm gear) are also placed in the gearbox housing.

When choosing the type of gearbox for driving the working element (device), it is necessary to take into account many factors, the most important of which are: the value and nature of the load change, the required durability, reliability, efficiency, weight and overall dimensions, noise level requirements, product cost, operating costs. Gearboxes are classified according to the following main features: gear type (toothed, worm or gear-worm); number of stages (single-stage, two-stage); type of gears (cylindrical, conical, etc.); relative location of reduction gear shafts in space (horizontal, vertical).

Of all types of gears, gears have the smallest dimensions, weight, cost and friction losses. The loss factor of a single gear pair with careful execution and proper lubrication does not usually exceed 0.01. Gear gears in comparison with other mechanical gears have great reliability in operation, constant gear ratio due to lack of slippage, and can be used in a wide range of speeds and gear ratios. These properties provided a large distribution of gears; they are used for capacities ranging from negligible (in instruments) to measured in tens of thousands of kilowatts.

Gearing Calculation

2.1 Selection of transmission material

Steel for gear - 45; heat treatment - improvement; tooth hardness: 269... 302 HB; yield strength αT = 650 MPa.

Steel for wheel - 45; heat treatment - improvement; tooth hardness: 269... 302 HB; yield strength αT = 650 MPa.

Developing a General Gearbox View Drawing

4.1 Selection of shaft material.

In designed reduction gears, it is recommended to use thermally treated medium-carbon and alloyed steels 45, 40X, the same for a high-speed and slow-speed shaft. In accordance with this, select steel 45.

Mechanical characteristics staly for production of shafts, N/mm2: σв =600, σт =320, σ1=260 .

Conclusion

As a result of the course design task, a typical design of a single-stage horizontal cylindrical helical gearbox for general purposes was developed. In the course of solving the task set in front of me, the method of selecting the drive elements was mastered, design skills were obtained to ensure the necessary technical level, reliability and long service life of the mechanism.

It can be noted that the designed reduction gear has good properties in all respects. Based on the results of calculation for contact endurance, the effective stresses in engagement are less than the permissible stresses. Based on the results of the calculation of bending stresses, the actual bending stresses are less than the permissible stresses. The calculation of the shaft showed that the safety margin is more than permissible. Required dynamic lifting capacity of rolling bearings is less than passport capacity. When calculating, an electric motor was selected that meets the specified requirements.