Supplemental Take Home Quiz, MECH4240, Fall 2016 Due: Thursday 9/22, 12:30, on paper Complete the following table on the computer. You will need to expand the height of rows in order to fit your entries into the cells. Figure Geometric Power Key Points in Force Description Engineering Modelling Between: Design Spur Gears Teeth parallel to Parallel shafts Most common type, Radial, cylinder axis moderate to low speeds tangential, no axial force Helical Gears Teeth that follow Parallel and Quieter operation Radial, axial on helical paths on nonparallel because teeth load and tangential the cylinder nonintersecting gradually and more shafts teeth in contact, higher speeds, higher loads Herringbone Gears Internal Gears Bevel Gears Spiral Bevel Gears Miter Gears Hypoid Gears Worm + Worm A worm is a screw Gear meshing with a spur-like gear called the worm gear Three R. R. Moore test specimens are made from steels having ultimate tensile strength of 95, 185 and 240 ksi. Estimate the 103 cycle fatigue strength for rotating bending and also the bending endurance limit for each steel. A 10 mm diameter steel bar having Su = 1200 MPa and Sy = 950 MPa has a fine-ground surface. Estimate the bending fatigue strength for (1) 106 or more cycles (2) 2 x 105 cycles. (3) Determine a factor of safety for infinite life if the steel bar has an internal moment M = 500 in-lb and compare to the factor of safety as if it were in static loading with the same internal moment. List all the different types of rolling-element bearings. For a particular application the bearing(s) is(are) expected to see large combined loading (both radial and axial) and substantial moment, in a locating bearing situation and loading in both axial directions. From the SKF table, choose the best bearing for this situation.
Supplemental Take Home Quiz, MECH4240, Fall 2016 Due: Thursday 9/22, 12:30, on paper Complete the following table on the computer. You will need to expand the height of rows in order to fit your entries into the cells. Figure Geometric Description Power Between: Key Points in Engineering Design Force Modelling Spur Gears Teeth parallel to cylinder axis Parallel shafts Most common type, moderate to low speeds Radial, tangential, no axial force Helical Gears Teeth that follow on helical paths on the cylinder Parallel and nonparallel nonintersecting shafts Quieter operation because teeth load gradually and more teeth in contact, higher speeds, higher loads Radial, axial and tangential Herringbone Gears Internal Gears Bevel Gears Spiral Bevel Gears Miter Gears Hypoid Gears Worm + Worm Gear A worm is a screw meshing with a spur-like gear called the worm gear Three R. R. Moore test specimens are made from steels having ultimate tensile strength of 95, 185 and 240 ksi. Estimate the 103 cycle fatigue strength for rotating bending and also the bending endurance limit for each steel. A 10 mm diameter steel bar having Su = 1200 MPa and Sy = 950 MPa has a fine-ground surface. Estimate the bending fatigue strength for (1) 106 or more cycles (2) 2 x 105 cycles. (3) Determine a factor of safety for infinite life if the steel bar has an internal moment M = 500 in-lb and compare to the factor of safety as if it were in static loading with the same internal moment. List all the different types of rolling-element bearings. For a particular application the bearing(s) is(are) expected to see large combined loading (both radial and axial) and substantial moment, in a locating bearing situation and loading in both axial directions. From the SKF table, choose the best bearing for this situation.
Gear_Fatigue_Bearings_Assignment_2016.docx