Wednesday, October 2, 2019
Mechanical design systems :: essays research papers
PROBLEM STATEMENT: Ã Ã Ã Ã Ã The design is to engineer a drive system to operate two extrusion rolls in opposite directions to compress the caramel. The drive system consists of a flexible drive system that operates a spur gear drive, which in turn operates the extrusion rolls at equal and opposite speeds. The power source to this design is a five horse power normal torque AC electric motor, operating at 1160 rpm. The system must be designed to run 24 hours per day, 3 days per week. There will be 4 shafts is the drive system. The shaft that is being driven by the flexible drive system directly is to be called shaft A, for design reference. The extrusion rolls shafts are to be called shaft B1 and B2, for design reference. The last shaft C is in the system only to reverse the direction of rotation of one of the extrusion roll shafts. The speed of shaft A is to be determined by the designer. The speed of the extrusion rolls is to be 200 rpm. When designing this drive system calculate all forces, life expectancies and stresses for both systems. The centerline distance from motor shaft to shaft A is to be 72 inches. 2 DESIGN DECISIONS: Ã Ã Ã Ã Ã While designing this multiple drive system there are many decisions to be made in order to successfully design the system according to the problem statement. The first is deciding whether to use a belt drive or a chain drive; one would realize that the system is operating at fairly low speed so a chain would be ideal. The next step to designing this system is to consider and analyze a speed for shaft A. Factors must be considered while deciding the speed of shaft A. The factors are that the speed of shaft A should be high enough so that the speed ratio of the gears is large enough, so that the gear sizes make a large enough distance between extrusion rolls. When designing this system one would choose around 480 rpm. Using the rpm out of the flexible drive one would select the appropriate gears for the application. Which the designer will find is a difficult task considering contact stress. When choosing the proper chain size and sprockets one will find that a numb er 40, 19 tooth Ã¢â¬Å"n1Ã¢â¬ and a 45 tooth Ã¢â¬Å"n2Ã¢â¬ are optimal stock components and get you fairly close to the desired 480 rpm.