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Calculate the axial force required to deflect the nested spring assembly a distance of 25 mm.
1. Two steel, helical-coil compression springs are to be nested around a common axial centerline. The outer spring is to have an inside diameter of 38 mm, a standard wire diameter of 2.8 mm, and 10 active coils. The inner spring is to have an outside diameter of 32 mm, a standard wire diameter of…
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Estimate the maximum stress in the wire at critical point B.
1.A round wire helical-coil tension spring has end loops of the type shown in Figures 14.7(a) and (b). The wire diameter of the spring is 0.042 inch, and the mean coil radius is 0.28 inch. Pertinent end-loop dimensions are riA 0.25 inch and riB 0.094 inch. An applied axial static tension force of F 5.0…
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Determine which coil (top or bottom, or one in the middle) deflects to zero pitch first as the force is increased.
1. A conical compression spring is made from 3-mm diameter steel wire and has an active coil diameter that varies from 25 mm at the top to 50 mm at the bottom. The pitch (distance between coils) is throughout. There are four active coils. A force is applied to compress the spring and the stress…
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Compute the existing safety factor for this spring based on an infinite-life design criterion. Comment on the results.
1.A helical-coil spring is to be wound using wire made from a proprietary ferrous alloy for which , , , , , and . It is desired to use the spring in a cyclic loading situation where the axial load on the spring during each cycle ranges from 450-N tension to 450-N compression. The spring…
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Design a leaf spring to meet these requirements if infinite-life is desired.
1.A multileaf simply supported truck spring is to be designed for each rear wheel, using AISI 1095 steel ( , , ). The truck weight is 16 kN, with 65 percent of the weight on the rear wheels. The static midspan deflection is 100 mm and the maximum midspan deflection during operation is 200 mm.…
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Find the circular tooth thickness.
1. Preliminary design calculations have suggested that design objectives may be met by a straight spur gearset using standard full-depth 2 -pitch involute gear teeth, and a 21-tooth pinion meshing with a 28-tooth gear. A 25 pressure angle has been selected for this application, and the gear teeth are to be shaved to AGMA quality…
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Estimate the increase in production cost of the appliance if gear shaving were used to achieve .
1.A straight-tooth one-stage spur gear reducer has been used in a high-production home appliance for many years. The gear pair constitutes about one-half the $50 production cost of the appliance. Consumer complaints about gear noise have grown over the years and sales are declining. One young engineer has found data that suggest the noise level…
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Calculate the percent difference in resultant force if the pressure angle were 25 instead of 20.
1. A straight-toothed full-depth involute spur pinion with a pitch diameter of 100 mm is mounted on an input shaft driven by an electric motor at 1725 rpm. The motor supplies a steady torque of 225 N-m. a. If the involute gear teeth have a pressure angle of 20, determine the transmitted force, the radial…
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Estimate the increase in production cost of the appliance if gear shaving were used to achieve .
1.A straight-tooth one-stage spur gear reducer has been used in a high-production home appliance for many years. The gear pair constitutes about one-half the $50 production cost of the appliance. Consumer complaints about gear noise have grown over the years and sales are declining. One young engineer has found data that suggest the noise level…
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Estimate the fatigue stress concentration factor for the tension-side root fillet of the driving pinion.
1. A 10-pitch 20 full-depth involute gearset with a face width of 1.25 inches is being proposed to provide a 2:1 speed reduction for a conveyor drive unit. The 18-tooth pinion is to be driven by a 15-hp, 1725-rpm electric motor operating steadily at full rated power. A very long life is desired for this…