Two mating 12 pitch gears have 18 external and 48 internal teeth respectively. Determine the following: (a) their pitch diameters and (b) the center distance.

You have been asked by your engineering company to design a complete gear and shaft system shaft that is made of steel. The solid shaft is linked with gear A, B. C and D with gear A., B and C produces torque of 15 kNm (clockwise), 30 kNm (clockwise) and 75kNm (anticlockwise). respectively each. If AB = 0.70m, BC= 0.80 m and CD=0.90 m with the shafts consist of solid circular shafts with a diameter of 150 mm having the shear modulus of G = 80 GPa, b) The shafts are now to be redesigned by drilling only through shaft BC with a diameter hole, cz to produce a hollow shaft BC. It is also known that the allowable shear stress, Tall in the shaft must not exceed 85 MPa. i) Determine the minimum wall thickness of the shaft BC, tBc

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A driving wheel of a gear has a radius of 20 cm and driven gear has 9 teeth along its circumference. If the driven wheel makes 5 rotation for every one rotation of the driving wheel. Calculate the rear ratio and diametral pitch