Worm-cylindrical gearbox - gearbox calculation

Contents

INTRODUCTION

1 DEVELOPMENT OF STRUCTURAL DIAGRAM OF DRIVE

1.1 Determination of mechanism mobility by Somov-Malyshev formula

2. Kinematic and power calculation

2.1. Electric motor selection

2.2 Calculation of parameters by drive shafts:

3.1 Material selection and allowable stress calculation

3.2 Design calculation of closed worm gear

3.3. Verification calculation

4. Calculation of low-speed internal chevron transmission

4.1 Choice of hardness, heat treatment and low-speed gear wheel material

4.2 Calculation of permissible bending stresses

4.2. Design calculation of closed cylindrical gear train

4.3 Check calculation of closed cylindrical gear train

5. Calculation of V-belt transmission

5.1 Design Calculation

5.2 Verification calculation

6. Thermal calculation of worm gear

7. Design calculation of shafts

7.1 Selection of shaft material

7.2 Determination of geometric parameters of shaft stages

7.2.1 Speed Gear Shaft

We determine the diameter of the output end of the shaft

7.2.2 Gearbox intermediate shaft

7.2.3 Gearbox output shaft

8.1 High Speed Worm Stage

8.2 Slow-moving cylindrical stage

9. Check of key connections

10. Determination of Gear Shaft Loads

10.1 Determination of forces in engagement of the first worm gear

10.2 Determination of forces in low-speed chevron gear engagement

10.3 Determination of cantilever forces

11. Selection of rolling bearings

11.1 Determination of reactions in bearings supports of high-speed shaft

11.2 Determination of reactions in bearing supports of intermediate shaft

11.3 Determination of reactions in supports of low-speed shaft bearings

12. Check calculation of bearings

12.1 Check calculation of high-speed shaft bearings

12.2 Check calculation of intermediate shaft bearings

12.3 Check calculation of low-speed shaft bearings

13 Selection of lubrication method and lubricant

13.1 Lubrication of gears

13.2 Lubrication of bearings

14. Refined Shaft Calculation

14.1 Calculation of high-speed shaft

14.2 Calculation of intermediate shaft

14.3 Calculation of low-speed shaft

15. Gearbox housing calculation

16. Assigning Part Fits

17. Gearbox Assembly Order

CONCLUSION

Introduction

The purpose of this course design is to design the electromechanical drive (EMI) of the conveyor.

The main issues related to EMF design are common for different types of drives. During EMF design it is necessary to solve the following tasks:

- correctly select the engine, having calculated its required power;

- find the total gear ratio of the gear box and break it into steps;

- calculate parameters of kinematic diagram of reduction gear box;

Electromechanical system consists of electric motor, transmission mechanism and, if necessary, control devices. Electromechanical drive (EMI) (electric motor and transmission mechanism) provides the required movement of equipment. Transmission mechanism (reduction gear) connects electric motor with actuating mechanism. The actuator creates a load on the output shaft of the reduction gear box.

Depending on the nature of the EMF operation, it is unregulated and adjustable or tracking. The non-adjustable drive provides the required movement of devices that are characterized by a long mode of operation at nominal characteristics.

Adjustable or tracking EMF is intended for operation in automatic systems. It is characterized by repeated-short-term operation modes, a large frequency of starts and reverses, the presence of control devices.

One of the goals of the project is to develop engineering thinking, including the ability to use previous experience, model using analogues. For the course project, objects are preferred, which are not only well distributed and of great practical importance, but also are not subject to moral aging in the foreseeable future.

There are various types of mechanical gears: cylindrical and conical, with straight teeth and oblique, hypoid, worm, globoid, one- and multithreaded, etc. This raises the question of choosing the most rational transmission option. When choosing the type of transmission, they are guided by indicators, among which the main ones are efficiency, overall dimensions, weight, smoothness of operation and vibration loading, technological requirements, the preferred number of products.

When choosing the types of gears, type of engagement, mechanical characteristics of materials, it should be borne in mind that material costs account for a significant part of the cost of the product: in general-purpose gears - 85%, in road cars - 75%, in cars - 10%, etc.

Finding ways to reduce the mass of designed objects is an essential prerequisite for further progress, a prerequisite for saving natural resources. Most of the energy currently generated is from mechanical transmissions, so their efficiency to a certain extent determines operating costs.

The most complete requirement for weight reduction and overall dimensions is satisfied by the drive using an electric motor and a reduction gear with external engagement.

Assigning Part Fits

Connection of internal rings of bearing rotating relative to radial load with shaft is performed with interference preventing rotation and rolling of conjugated stage of shaft by ring. Create tension on the mounting surfaces of the shaft and worm wheel.

Fits of external bearing rings fixed relative to radial load are selected to be freer, allowing for small clearance.

Shaft tolerance field for internal bearing ring at circulation loading: for roller - k6, m6.

The tolerance field of the hole for the outer ring of roller bearings is H7.

For the gear, fit H7/r6 is accepted.

Key width tolerance field - h9; key slot width tolerance field N9

During reverse operation with large tremors and blows, landing under the couplings is taken as H7/n6.

Gearbox Assembly Order

Prior to assembly, inner cavity of housing is thoroughly cleaned and covered with oil-resistant paint. Serviceability of gear box units and parts is checked. Assembly is performed in accordance with installation drawing.

The body of the gearbox is cast, with horizontal connectors, consists of two parts - a base, a cover.

Bearings are fitted on high-speed shaft of reduction gear box. Bearings are fixed in the housing by means of sealing gaskets, and sealed with tie-in covers.

Gear wheel is pressed onto intermediate shaft until stop against collar. The wheel is connected to the shaft using a key. Then spacer ring and pair of conical roller bearings are fitted.

A gear wheel is pressed on the slow-moving one. Connection with shaft by means of key. A spacer ring is worn and bearings are installed.

Oil protection washers with hub are used to prevent grease ingress into reducer. End and cut-in covers are used for sealing. Solid grease is packed into bearings. After the shafts are installed, the housing is closed with a cover. Then the parts of the gearbox housing are fixed with pins and connected by bolts (screws).

Iron oil indicator, drain hole plug is installed. The required amount of oil is filled through the inspection window of the reduction gear box. The inspection hole is closed with a cover .

Reduction gear is installed on frame and is connected to shaft of electric motor installed on the same frame by means of V-belt transmission, and to winch drive by means of elastic coupling.

Serviceability check is performed.

Conclusion

In the course design, a drive based on a two-stage worm-cylinder reduction gear and open V-belt gear is designed and designed.

Based on kinematic calculation, AIR132S6 electric motor with rated power Pnom = 5.5 kW and rated speed n = 960 rpm is selected, transmission ratio of drive uf = 200 is determined.

When calculating gears, the main parameter is determined - the axial distance, the material is selected and a check calculation is made.

During design calculation of bearings dynamic load capacity of bearings and their basic durability were calculated. When comparing these parameters with the base load capacity and the required durability, the suitability of the bearings is determined.

Design and verification calculations of V-belt transmission were made.

Crankcase method of reduction gear box lubrication with lubricating oil of grade I-G-A-68 GOST 17479487 is selected.

The gearbox assembly order is defined.

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