Project overview: The objective of this project is to design a speed reducing (torque increasing) gearbox for an industrial bending application. Your design team is required to specify the associated shafts, rolling element bearings, keyways, keys, housing and gears to a level of detail (including CAD drawings) such that the entire system could be manufactured without any additional comment from you.
Specific requirements:
1. The electric motor that powers the speed reducing gearbox has the following specifications:
• Basic rated power: X.YkW (X and Y are the last digits of P1 and P2 student numbers)
• Shaft speed (full-load): 1,200 RPM
• The electric motor will provide at most a "light" shock loading
• The motor runs in one direction only, and will start-stop 20 times per day
• The system should operate 10 hours per day, S days per week with a design life of 10 years
2. The speed reducing gearbox should provide the following:
• The Train Ratio should be as close as 10.0 as possible
• Allow for an output which may be subject to "moderate" shock
• Gears to be manufactured with either Hobs (shaping cutters) or Precision (shaved and ground). Precision gears are more costly, and this decision should be justified.
3. Gears should be designed according to the procedure demonstrated in class and available in Chapter 15 of Juvinall and Marshek Fundamentals of Machine Component Design, and should satisfy the following:
• All gear sets must have a hunting tooth ratio
• The minimum number of teeth on a pinion is 13
• The reliability of the gears should be 99%
• Pinions can be machined onto shafts if required
4. Shafts should be designed to Australian Standards and should:
• Include a shoulder to precisely locate all gears
• Keyways and keys must be designed to allow mounting of all gears
5. Housing
• The housing must allow assembly of all components
• Feet must be provided to allow bolting to a horizontal surface
• Lubrication of the gears and bearings must be accommodated
6. Bearings
• Appropriate, sealed, single-row, deep-groove, ball bearings should be specified from a commercial supplier (for example: skf.com, fag.de, nsk.com).
• The bearings should provide a reliability of 90%
• The bearing fit with the shaft shall be K8/g6 (for purposes of stress concentration prediction, Figure 5, AS 1403 Design of rotating steel shafts).