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15-15 to 15-22 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
15-17 | AGMA | Steel, HRC 58 | Centrifugal-cast bronze |
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 MECH.ENGINEERING DESIGN-EBK>I
- A steel shaft 800 mm long transmitting 15 kW at 400 r.p.m. is supported at two bearings at the twoends. A gear wheel having 80 teeth and 500 mm pitch circle diameter is mounted at 200 mm from theleft hand side bearing and receives power from a pinion meshing with it. The axis of pinion and gearlie in the horizontal plane. A pulley of 300 mm diameter is mounted at 200 mm from right hand sidebearing and is used for transmitting power by a belt. The belt drive is inclined at 30° to the vertical inthe forward direction. The belt lap angle is 180 degrees. The coefficient of friction between belt andpulley is 0.3. Design and sketch the arrangement of the shaft assuming the values of safe stresses as :τ = 55 MPa; σt= 80 MPa. Take torsion and bending factor 1.5 and 2 respectively.arrow_forwardA pair of gray iron and steel helical gears, having a helix angle of 15° with 20° full-depth teeth are to transmit 10 hp at 1500 rpm of a 4-in pinion having a total number of 28teeth. The velocity ratio desired is about mw = 4. Find the (a) normal circular pitch, (b) normal diametral pitch, (c) axial pitch, and (d) dynamic loaarrow_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
- 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_forwardProvide 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_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_forward
- A 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_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 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_forward
- The figure shows a double-reduction helical gearset. Pinion 2 is the driver, and it receives a torque of 1200 Ibf • in from its shaft in the direction shown. Pinion 2 has a normal diametral pitch of 8 teeth/in, 14 teeth, and a normal pressure angle of 20° and is cut right-handed with a helix angle of 30°. The mating gear 3 on shaft b has 36 teeth. Gear 4, which is the driver for the second pair of gears in the train, has a normal diametral pitch of 3 teeth/in, 15 teeth, and a normal pressure angle of 20° and is cut left-handed with a helix angle of 15°. Mating gear S has 45 teeth. Find the magnitude and direction of the force exerted by the bearings C and D on shaft b if bearing C can take only a radial load while bearing D is mounted to take both radial and thrust loads.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_forwardA pair of spur gear fitted on a motor shaft of lathe machine transmits the power of 7 kW at 600 rpm which is input at pinion gear and its shaft rotates in the counter-clockwise direction. The number of teeth on the pinion and the gear are 22 and 72 respectively, while the module is 8 mm. Assume a pressure angle of 200. Calculate: i) Torque on the shaft of the pinion in Nm. ii) Torque on the shaft of the gear in Nm. iii) Gear ratio iv) Center distance between shafts in mmarrow_forward
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