Page 433 - Shigley's Mechanical Engineering Design

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408 Mechanical Engineering Design
7–42 A gear and shaft with nominal diameter of 35 mm are to be assembled with a medium drive fit,
as specified in Table 7–9. The gear has a hub, with an outside diameter of 60 mm, and an overall
length of 50 mm. The shaft is made from AISI 1020 CD steel, and the gear is made from steel
that has been through hardened to provide S u 700 MPa and S y 600 MPa.
(a) Specify dimensions with tolerances for the shaft and gear bore to achieve the desired fit.
(b) Determine the minimum and maximum pressures that could be experienced at the interface
with the specified tolerances.
(c) Determine the worst-case static factors of safety guarding against yielding at assembly for the
shaft and the gear based on the distortion energy failure theory.
(d) Determine the maximum torque that the joint should be expected to transmit without slipping,
i.e., when the interference pressure is at a minimum for the specified tolerances.