Drive of tumbling drum for removal of burrs after stamping

Contents

Contents

Introduction

1. Energy, kinematic and power calculations of the drive

1.1 Determination of rated power and rated engine speed

1.2 Determination of gear ratio of the drive and its stages

1.3 Determination of kinematic and power parameters of the drive

2. Calculation of outpatient transmission

2.1 Design calculation

2.2 Verification calculation

3. Gearbox Gear Calculation

3.1 Selection of hardness, heat treatment and gearing material

3.2 Determination of allowable contact stresses

3.3 Determination of allowable bending stresses

3.4 Design calculation of closed cylindrical gear train

3.5 Check calculation of closed cylindrical gear train for contact strength

3.6 Check calculation of closed cylindrical gearing for endurance by bending stresses

4. Design calculation of gear box shafts

4.1 Selection of shaft material and allowable torsional stresses

4.2 Selection of couplings, sizing of shaft stages

4.3 Preliminary selection of rolling bearings

5. Gear Design

5.1 Define the design and dimensions of the cylindrical gear (rim, hub, disk)

6. Gearbox Sketch Layout

7. Gear shaft loads

7.1 Power diagram of reduction gear box shafts loading

7.2 Determination of cantilever forces and forces in closed gear engagement

7.3 Design diagrams of high-speed and slow-speed shafts

7.4 Determination of radial reactions in shaft supports

7.5 Construction of curves and torques

8. Check calculation of rolling bearings

8.1 Check suitability of bearings 36308 of high-speed gear shaft operating with moderate tremors

8.2 Check suitability of bearings 36210 of low-speed gear shaft operating with moderate tremors

9. Selection and check calculation of key connections

9.1 Key Selection

9.2 Check of key crushing strength

10. Check calculation of gear box shafts

10.1 Selection of Hazardous Sections

10.2 Determination of normal stresses, MPa, in hazardous sections of shaft by formula

10.3 Determination of tangent stresses, MPa, in hazardous sections of shaft by formula

10.4 Determination of concentration factor of normal and tangent stresses for design sections of shaft by formulas

10.5 Determination of endurance limits in design sections of shaft,, MPa, by formulas

10.6 Determination of safety factors by normal and tangent stresses by formulas

10.7 Determination of total safety factor in design sections by formula

11. Purpose of fits, feature tolerances for gearbox main parts

12. Sizing of main elements of gearbox housing and drive welded frame

12.1 Gearbox housing

12.2 Drive frame

13. Gearbox lubrication and assembly

14. Gearbox assembly

15. Occupational safety, technical aesthetics

Conclusion

List of literature

Introduction

The rules of design and design of design documentation establish four stages of its development: terms of reference, draft design, technical design, working documentation. The course project on the discipline of Machine Details is presented in the form of an explanatory note, an assembly drawing of a reduction gear, a drawing of a cylindrical gear wheel and a slow-moving shaft.

The assignment to the course design provides for the development of the design of a single-stage cylindrical reduction gear of the drive of the tumbling drum for removal of burrs after stamping.

The drive device includes a motor, a transmission with a polyclinic belt, a cylindrical reduction gear, an elastic bushing sleeve clutch and a tumbling drum.

The initial data for the design are: circumferential force on the drum = 1.0kN; peripheral speed of the drum = 2.5 m/s; drum diameter = 600 mm; allowable deviation of drum speed = 5%; drive life = 5 years.

The reduction gear is designed to transfer power from the engine shaft to the drive shaft of the working machine, reduce angular speeds and, accordingly, increase the rotating torque of the driven shaft compared to the drive shaft. The reduction gear consists of a housing, in which the transmission elements are placed - gears, shafts, bearings, etc.

Devices for lubrication of engagement and bearings are also arranged in reduction gear case.

The main requirements for the created drive: reliability, processability, repairability, minimum dimensions and weight, usability, technical aesthetics. All these requirements are taken into account in the design and design process.

Sizing of main elements of gearbox housing and drive welded frame

12.1 Gearbox housing

The shape of the housing is determined mainly by technological, operational and aesthetic conditions, taking into account its strength and rigidity. These requirements are met by rectangular-shaped housings with smooth outer walls without projecting structural elements; bearing bosses and ribs inside; covers of bearing units are mainly cut-in; the fundamental legs do not protrude beyond the dimensions of the body.

The most common method of manufacturing casings is casting from gray cast iron of grade CH 15, GOST 141279. The dimensions of the main elements of the housing in the area of the lower flange, flange by connector and bearing assembly are determined depending on the axial distance of aW=180 mm in accordance with the recommendations.

The wall thickness of the gearbox (gearbox cover) is 8 mm.

12.2 Drive frame

The bearing element of the drive frame is a channel, the type and size of which, as well as the dimensions of the oblique washer, are determined depending on the largest diameter of the bolt attaching the reduction gear box (or electric motor) to the frame. In our case, the diameter of the lower flange bolt of the gearbox - M12, which, according to the recommendations, corresponds to channel No. 14, GOST 824072, is of greater importance.

Gearbox lubrication and assembly

Lubrication of gear engagement is carried out continuously by liquid oil I-G-A-68 GOST 17479.487 using a crankcase method (using sprinklers). For single-stage reduction gears, when dipping, the volume of the oil bath is determined based on 0.4... 0.8 l of oil per 1 kW of transmitted power.

We determine the oil level so that the oil level passes through the center of the bearing lower rolling body.

For oil replacement in the housing there is a drain hole closed by a plug with cylindrical thread. To avoid pressure increase inside the housing and oil leakage through the seals and joints, install a cap fragrance in the cover of the reducer housing.

Bearings are lubricated with plastic materials. Lubricant is packed into bearing manually at removal of bearing assembly cover for several years. Lubricant is changed during repair. To prevent the lubricant from flowing out of the bearing assemblies, as well as to protect them from dust, dirt and moisture ingress, we use cuff seals.

The reduction gear is assembled in accordance with the assembly drawing.

Prior to assembly, inner cavity of reducer housing is thoroughly cleaned and covered with oil-resistant paint.

Gearbox assembly

Assembly is done in the following order:

sprinklers are installed on high-speed shaft and fixed with screws and bearings preheated in oil are pressed to rest against shaft collar. The assembled shaft is installed in the base of the gear box housing;

- installation of compensating rings between ends of external rings of bearings and covers;

- a cuff is installed in the cover with the hole, then the cover is installed on the high-speed shaft (left support); installing a blind cover (right support) in the base of the housing;

middle part of body and base are fixed by means of mounting pins, coupling screws of connecting flange are installed and clamped.

- key for gear wheel is laid on slow-moving shaft, wheel is pressed until stop against shaft collar. Spacer bushing is installed and bearings preheated in oil are pressed to stop against shaft collar. Assembled shaft is installed in middle part of reduction gear box housing. The engagement is adjusted;

- installation of compensating rings between ends of external rings of bearings and covers;

- the cuff is installed in the cover with the hole, then the cover is installed on the slow-moving shaft (right support); installing a blind cover (left support) in the middle portion of the housing;

- fixing the cover of the housing and the middle part by means of locating pins, mounting and clamping the coupling screws of the connecting flange;

keys are laid in slots of shafts under pulley of belt gear and half-coupling. The drain plug and oil indicator are screwed into the reduction gear box housing;

- oil is poured and inspection hatch with perfume plug is closed.

Control of radial thrust ball bearings is performed by installation of compensating rings between ends of external rings of bearings and covers.

Note here that clearance mm is left between bearing outer ring end and cover end with hole to compensate for thermal deformations.

Conclusion

At all stages of the design development of the gearbox, I thought about the cost-effectiveness of the decisions made, possible manufacturing and assembly technology, operating and maintenance conditions, service life and reliability of the gearbox:

- An important indicator of the perfection of the design is the condition of equal durability of all elements;

- it is recommended to select a high-speed motor with a synchronous speed of at least 1000 rpm, i.e. relatively small. This causes, firstly, the low cost of such a serial engine and, secondly, a decrease in the labor intensity of its assembly with a reduction gear;

- standard products (bearings, couplings, fasteners, seals, drain plugs, air plugs, etc.), as well as standards for various elements of the designed parts (recesses, fillets, casting slopes, etc.) are widely used in the design;

- at all stages of gearbox design the principle of unification was observed (types and dimensions of rolling bearings, gear wheel modules, fasteners, mounting dimensions and materials);

- fits, tolerances, degrees of accuracy and cleanliness classes of the surface of the parts are selected from the position of their influence on the operational properties of the reduction gear box and matching with technological capabilities of production, the hole system and rows of preferred numbers are used;

- economic aspects are taken into account in the selection of material, heat treatment, shape and methods of manufacturing parts;

- when designing, attention is paid to the implementation of convenient assembly, manual operations, incorrect mutual arrangement of mating units (using pins) are excluded as much as possible, a convenient arrangement of units with easily accessible attachment points has been developed;

- recommendations on lubrication and lubricating devices are used to reduce corrosion-mechanical wear.

For safe operation of the gearbox, observe the following conditions:

- perform external inspection of parts before assembly to detect defects;

- do not use too much effort when assembling gear box units;

- make two adjustments correctly in the gear box units and between them;

- all fasteners must be tightened and fixed with locking washers;

- do not start the gearbox without lubrication or without its sufficient quantity;

- avoid exceeding the speed and power of the reduction gear box;

- all rotating parts of the gearbox protruding beyond its housing must be protected;

- have devices for gearbox filling during transportation and installation works;

- do not repair and maintain the reduction gear box during its operation;

- remove the covers closing the inspection windows during operation of the reduction gear box to avoid spraying of heated oil;

- check the oil level, replace with fresh oil and drain spent oil only at full stop of the drive;

- it is not recommended to press the drain plugs to avoid thread failure; - during installation works, it is necessary to disconnect the electrical power supplies from the mains, check the grounding and remove external loads on the shafts. Compliance with these requirements ensures reliable and safe operation of the gearbox, which significantly increases the economic effect.