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15-15 to 1 5-22 As in Ex. 15–4, design a cylindrical worm-gear mesh to connect a squirrel-cage induction motor to a liquid agitator. The motor speed is 1125 rev/min, and the velocity ratio is to be 10:1. The output power requirement is 25 hp. The shaft axes are 90° to each other. An overload factor Ko (see Table 15–2) makes allowance for external dynamic excursions of load from the nominal or average load Wt. For this service Ko = 1.25 is appropriate. Additionally, a design factor nd of 1.1 is to be included to address other unquantifiable risks. For Probs. 15–15 to 15–17 use the AGMA method for
EXAMPLE 15-4 Design a 10-hp 11:1 worm-gear speed-reducer mesh for a lumber mill planer feed drive for 3- to 10-h daily use. A 1720-rev/min squirrel cage induction motor drives the planer feed (Ka = 1.25), and the ambient temperature is 70°F.
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SHIGLEY'S MECHANICAL ENG.DESIGN W/CODE
- A 15 kW and 1200 motor drives a compressor at 300 a pair of spur gears having . The center-to-center distance between the shafts is 400 . The motor pinion is made of forged steel having an allowable static stress as 210 MPa, while the gear is made of cast steel having allowable static stress as 140 MPa . Assuming that the drive operates 8 to 10 hours per day under light conditions , find from the standpoint of strength Module , 2. Fare and 3. Number of teeth and pitch circle diameter of each gear 2. Check the gears thus designed from the consideration of Static tooth load or endurance strength of the tooth flexural endurance limil (sigma_{\epsilon}) may be taken as 400 MPa 3. Check the gears thus designed from the consideration of wear surface endurance limit ( sigma epsilon x ) may be taken 700 MPa b ^ pi ( 6.154 - 0512/pi; F_{N}arrow_forwardA truck equipped with a 50 HP engine uses a roller chain as the final drive to the rear axle. The driving sprocket runs at 225 rpm with a center distance of approximately 500 fpm. The transmission efficiency between the engine and the driving sprocket is 85%. 1.1 Determine the pitch and width of chain to be used. 1.2 Determine the number of teeth in each sprocket and the pitch diameters.arrow_forwardA 21-tooth pinion rotating at 1000 rpmrpm meshes with a 33-tooth gear in a spur-gear reducer. Both pinion and gear are manufactured to a quality level of 9. A reliability of 0.9 has been specified and the transmitted tangential load is 2500 lblb. Conditions are such that Cm= 1.7. It is proposed that standard 25∘∘, full-depth teeth be used, with both pinion and gear hobbed from an AISI 4140 nitrided steel. The diametral pitch is 6, and the face width 2.000 inin. Suppose that the life of the pinion will be less than that of the gear, the lubricant bulk temperature does not exceed 250∘F∘F, both driver and driven devices are smooth-running, the gearset is external, gears made by conventional methods. Use the average value for the uncorrected surface-fatigue strength when choosing it from the appropriate table. Assume that the reducer is used for critical service applications. a)What is the dynamic factor (Cv) for the pinion? b)What is the AGMA Surface-Geometry Factor(I) for the pinion/gear…arrow_forward
- A 17-tooth 20° pressure angle spur pinion rotates at 1800 rev/min and transmits 4 hp to a 52-tooth disk gear. The diametral pitch is 10 teeth/in, the face width 1.5 in, and the quality standard is No. 6. The gears are straddle-mounted with bearings immediately adjacent. The pinion is a grade 1 steel with a hardness of 240 Brinell tooth surface and through-hardened core. The gear is steel, through-hardened also, grade 1 material, with a Brinell hardness of 200, tooth surface and core. Poisson's ratio is 0.30, Jp = 0.30, JG = 0.40, and Young's modulus is 30(10°) psi. The loading is smooth because of motor and load. Assume a pinion life of 108 cycles and a reliability of 0.90, and use YN = 1.3558N-0.0178, ZN = 1.4488N-0.023. The tooth profile is uncrowned. This is a commercial enclosed gear unit. (a) Find the factor of safety of the gears in bending. (b) Find the factor of safety of the gears in wear. (c) By examining the factors of safety, identify the threat to each gear and to the…arrow_forwardA gear set with a 20-tooth input pinion and a 42-tooth gear has a diametral pitch of 4 teeth/in. the pinion speed is 200 rpm with an input torque of 170 in-lbf. Which component of the load contributes to the transmitted power and what is it’s magnitude? Choose answer below Radial load 68lbf Tangential load 68lbf Radial load 136 lbf Tangential load 136 lbf None of the abovearrow_forwardFor the gear mechanism in the figure: P1 = 4 kW, η1 = 1000 rpm, z1 = 18, z2 = 36, z3 = 54, z4 = 108, z1 is the driving gear. Total efficiency values for each stage; Since η12 = η34 = 0.96; Find the output torque and speed of gear z4.arrow_forward
- Provide very clear and complete solution and diagam. SITUATIONAL PROBLEM: Two shafts are connected by spur gears. The pitch radii of the gears A and B are 200 mm and 860 mm respectively. If shaft A makes 350rpm and is subjected to twisting moment of 250 N-m. Pressure angle is 14.5 degree. What is: a.) Rpm of gear B b.) Torque in shaft B (in Newton meter). c.) Separation load of two gears (in newtons). d.) Total load on gears (in newtons).arrow_forwardA pair of gears with 20° full-depth teeth are to transmit 15hp at 1750 rpm of the 4-in pinion; velocity ratio desired is about mw= 4; intermittent service. Use a strength reduction factor of about 1.4, with the load at the tip and teeth carefullycut. A.Determine the diametral pitch, B. face width, C. and tooth numbers if the material is cast iron, class 25arrow_forwardA pair of gears with 14.5° full-depth teeth are to transmit 5 hp at 1800 rpm of the pinion; mw= 2.5; Np = 20 teeth; carefully cut teeth; intermittent service; Kf= 1.45. A. Determine the diametral pitch, B. face width, C. and tooth numbers if the pinionis to be made of phosphor gear bronze (SAE 65, Table AT 3arrow_forward
- A belt conveyor transports 18 tonnes per hr at 20°. Determine the speed reducer power factor to lift the load vertically up sufficient to give 33.5 m horizontal center-to-center pulley distance. 1750-rpm motor, plain chain drive to helical gear speed reducer. Belt speed, 61 m/min. Discharge over tail pulley. No tripper.arrow_forward13-32 The 247 6-pitch 20° pinion 2 shown in the figure rotates clockwise at 1000 rev/min and is driven at a power of 25 hp. Gears 4, 5, and 6 have 24, 36, and 144 teeth, respectively. What torque can arm 3 deliver to its output shaft? Draw free-body diagrams of the arm and of each gear and show all forces that act upon them.arrow_forwardThe client requires a single step-up spur gearbox to transmit a 10 kW power from a shaft rotating at 1000 rpm, while the output speed must be 1700 rpm. The material for gear and pinion is 817M40 and 655M13, respectively. Use table 6.10 on page 128 to select the suitable gear and pinion. 1.1 Briefly state the problem. 1.2 State the design specification considering the following design factors: 1. Functionality 2. Stress 1.3 State formula and standards relevant to the single step-up spur gearbox design. 1.4 If the pinion has 20 teeth, use the Lewis formula to determine the face width of the pinion and gear. Then, do one set of calculations and tabulate the answers. 1.5 Conclusion.arrow_forward
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