Course design "worm-cylindrical gearbox"

Contents

Contents

Introduction

1 Kinematic and power calculation of the drive

Electric motor selection

Determination of power and kinematic parameters of drive shafts

2 Calculation of gears

2.1 Calculation of cylindrical gear train

2.1.1 Gear and gear materials, allowable stresses

2.1.2 Transmission Design Calculation

2.1.3 Check of design contact stresses

2.1.4 Check of design bending stresses

2.2 Calculation of worm gear

2.2.1 Material Selection for Gears

2.2.2 Transmission Design Calculation

2.2.3 Basic transmission parameters

2.2.4 Strength Transmission Check Calculation

2.3 Calculation of V-belt transmission

3 Calculation and design of shafts

3.1 High speed shaft

3.2 Intermediate shaft

3.3 Slow-moving shaft

4 Calculation of key connections

5 Calculation and design of bearing units

5.1 High speed shaft

5.2 Intermediate shaft

5.3 Slow-moving shaft

6 Design of gear and worm wheels, worms and pulleys

7 Construction of housing parts, cups and covers

8 Lubrication of hooks

9 Selection and check calculation of couplings

10 Frame Design

11 Selection of fits

12 Gearbox assembly and adjustment

13 Safety precautions

Conclusion

List of sources used

Appendix A - Specification for gearbox assembly drawing (4 sheets)

Appendix B - Specification for General Drive Type (2 Sheets)

Appendix B - Frame Assembly Drawing Specification (1 Sheet)

8 Lubrication of hooks

During the design of the drive, gears (except belt) and bearings are subject to lubrication. The purpose of lubrication is to protect against corrosion, reduce the intensity of wear of friction surfaces, remove heat and wear products, as well as reduce noise.

Lubrication of gear and worm gears.

To lubricate closed gears, a crankcase lubrication system is widely used - dipping the teeth of the wheels into oil poured into the body.

With crankcase lubrication, it is enough that one wheel of lubricated steam is immersed in the oil.

The depth of immersion in oil of cylindrical gear wheels is two tooth heights, at least 10 mm. The high-speed stage, in this case, does not dip into the oil. The depth of immersion in worm wheel oil is at least 2,2∙m.

Lubrication of rolling bearings.

Lubrication of the rolling bearings will occur when oil is sprayed with gears, oil mist is formed and oil enters the bearings due to its drain from the shafts and walls of the housing.

Installation of containment rings is not required as the oil level does not exceed the center of bearing rolling bodies.

Rubber reinforced collar is used as external seals of bearing assemblies (as per GOST 8752-79).

Choice of oil grade.

Depending on the contact voltage in the hooks and the circumferential speed of the gears, we accept industrial oil I30A GOST 20799-75. The same oil will lubricate the bearings of the reduction gear box due to spraying.

Oil level monitoring.

Monitoring of oil level in the gear box housing is performed using the oil indicator. In the designed reduction gearbox, oil level monitoring is carried out using a round oil indicator made of organic glass, the dimensions of which are assumed as per Table 13.1.4 [1, c. 185].

Oil drain.

To drain spent oil in the housing, a drain hole is provided, which is closed by an oil plug with a cylindrical thread, the dimensions of which are shown in Table 13.1.5 [1, c. 185].

Gearbox assembly and adjustment

Assembly method. We assemble the reducer according to the assembly drawing and the specification for it. We accept the most progressive method of assembly - node-by-node.

Parts that meet the requirements of working drawings and regulatory and technical documentation and are accepted by technical control are put into assembly.

High-speed shaft assembly. Prismatic key is installed in keyway and worm is pressed. Bearings prepared for installation, heated in the oil bath up to t = 100 ℃, are installed on the shaft. Shaft together with bearings and sleeve are installed in appropriate sockets. Prismatic key is installed in key slot and pulley is pressed.

Intermediate shaft assembly. Prismatic key is installed in keyway and worm wheel is pressed. Bushing is pressed against wheel. Gears are installed similarly. Bearings are installed on shaft ends. Shaft together with bearings are installed in bearing sockets.

Low-speed shaft assembly. Prismatic keys are installed in key slots and cylindrical gear wheels are pressed. Then bushings are pressed against wheel. Bearings are similarly installed on shaft ends. Half-coupling is installed on output end of shaft.

Shaft knots. Assembled shaft units are installed in the gear box housing prepared for assembly (painted from inside with red oil-resistant paint) in bearing sockets. Plane of body connector and covers are covered with sealant and body cover is installed. Two cylindrical pins are installed to fix cover position. Flange bolts are tightened.

Bearings. Bearing covers with collars are installed and secured by pressure bolts.

Butter. An oil discharge plug is installed in the threaded window of the housing. Oil is poured .

Observation hatch. Inspection hatch is closed with cover and gasket and fixed with 4 bolts.

Adjustment. The gearbox is adjusted and run-in according to the test program.