When in use, the motor and flywheel of a punch press run continuously. A compressed-air-actuated, multiple-disk clutch connects the flywheel to the countershaft each time the press is to punch or form metal. The clutch torque required is 600 N m. Alternate sintered metal and cast-iron disks are to be used. For design purposes it is decided to use 75 percent of the average value of f, and one-third of the average value of p given in Table 18.1. In addition, a safety factor of 1.20 is to be used with respect to torque capacity. Space requirements limit the disk outside diameter to 250 mm.
(a) Determine the minimum satisfactory total number of disks.
(b) Using this number of disks, determine the minimum area of compressed-air actuating surface that must be provided if air will always be available at a pressure of at least 0.40 MPa.
