10. 1. 12, 13, ‘A.work rotating at 1150 rpm drives a worm gear. The velocity ratio is 15 to 1. A 10 hp motor is used to supply ‘the worm with worm pitch gear diameter of 3 in. Find the tangential force on the worm. A. 365.37 Ibs B. 465.37 Ibs C. 565.37 Ibs D. 685.37 bs A double thread worm gear has a pitch of 1 1/8 and a pitch diameter of 3 in. It has a coefficient of friction of 0.20 ‘and normal angle (pressure angle) of 14.62. The worm is supplied by 12 hp at 1200 rpm motor. Find the tangential force on the gear. The worm is left hand threads. ‘A. 597.08 Ibs B. 697.08 Ibs ©. 797.08 Ibs D. 897.08 bs Assingle worm gear has a pitch diameter of 2 in and a pitch of 1 in with coefficient of friction of 0.21. The normal ‘angle is 14.5 degrees with tangential force on gear of 1000 Ibs. Find the separation force on gear and worm ‘considering 2 left-hand thread. A. 171.23 Ibs B. 271.23 Ibs ©. 371.28 Ibs D. 471.23 bs ‘A double thread worm gear has a lead angle of 7.25 degrees and pitch radius of 2 %4in. Find the pitch of the worm. A. %in B %in C. tin D.1%in triple thread worm gear has a helix angle of 78 degrees. It has a pitch of %in. Find the pitch diameter of the gear. A. 2.37in B.277In ©. 3.07 in D. 337 in A double thread worm has a lead of 1.5 in and pitch diameter of 3.5 in. Ifnormal pressure angle is 14.5 degrees, find the pressure angle of the worm. A. 11.689 B. 1268° C. 13.68° D. 14.68 A\triple thread worm gear has pitch of % in and pitch diameter of 2 %4 in. Find the helix angle. A. 7234 B. 6234" C. 92.34" D. 42.34 A three-thread worm, rotating at 1,000 rpm, drives a 31-tooth gear. Find the speed of the gear. A. 7677 1pm B. 86.77 pm C. 96.77 rpm D. 106.77 rpm ‘A double thread worm having @ pitch of 1 in is used to drive a 40 teeth gear. Find the pitch diameter of the gear. A. 9.73 in B. 10.73 in ©. 11.73in D. 12.73in triple thread worm gear is used to drive a 25 taeth gear having a pitch of % in. Find the center distance. A. 2.34 in B. 3.34in C. 4.34 in D. 5.34 in ‘A double thread worm has a helix angle of 82° and a pitch diameter of 1 %4in. The worm rotates at 800 rpm. Find the linear speed of the worm. ‘A. 129.82 fpm B. 199.82 fpm C. 149.82 fom D. 159.82 fpm Atriple thread worm gear having a diametral pitch of 5 in is used to deliver a gear. The speed ratio is 10. Find the pitch line velocity of gear id the worm rotates at 600 rpm, ‘A. 64.25 fpm B. 74.25 fpm C. 84.25 fpm D. 94.25 fpm ‘A double thread worm gear having a pitch of 1 in and has a linear speed of 200 fpm. The pitch diameter of worm sin. Find the tangential speed of the worm. A. 1,258.64 fpm B. 1,358.84 fpm CC. 1,456.84 fpm D. 1,586.64 fpm14, 15. 16. 17. 18, 19, 21. 23. 28. triple thread worm gear has a pitch of % in and pitch diameter of 3.5 in. The normal pressure angle is 14.5 degrees and coafficient of friction is 0.10. Find the worm efficiency, A. 50.05% B. 55.05% C. 60.05% D. 65.05% A triple thread worm gear has normal pressure angle of 14.5° and coafficient of friction is 0.15. If worm efficiency is 70%, find the lead angle. ‘A. 25.14 B. 27.74° c. 29.74% D. 31.74% ‘Aworm has four threads of 14.5° normal pressure angle and pitch diameter of 4 %4in. The gear has 52 teeth of 1 %in pitch. Find the canter distance of the shafts. A. 1261 in B. 1461 in C. 16.61 in D. 18.61 in ‘Aworm has four threads of 14.5° normal pressure angle and pitch diameter of 4 Yin. The gear has 52 teeth of 1 %in pitch. Find the efficiency of the worm if friction is 0.03. A. 82.88% B. 86.88% C. 69.88% D. 92.88% A triple thread worm has a pitch diameter of 3 inches. The wheel has 25 teeth and a pitch diameter of 5 inches. Material for both the worm and the wheel is of phosphor bronze. Compute the helix angle. A020 B. 0.30 c. 0.40 D. 14 A\tnple thread worm gear is used to drive a 25 teeth gear having a pitch of % in. Find the center distance. ‘A. 2.34 in B. 3.34in C. 4.34 in) D. 534in |. A double threaded right-handed worm gear transmits 15 HP at 1150 rpm. The pitch of the worm is 0.75 inches and pitch diameter of 3 inches. The pressure angle is 14 and % degrees and the coefficient of friction is 0.12. Find the separating force in pounds. ‘A. 504 Ibs B. 501 Ibs C. 407 bs D. 5091 Ibs ‘A.20-ooth helical gear hes a pitch diameter of 10 in. Find the diametral pitch of the gear. Az B.3 C4 D5 28 -tooth helical gear having a pitch diameter of 7 has a helix angle of 22 degrees. Find the circular pitch ina plane normal to the teeth. A. 0528 B, 0.628 c. 0.728 D. 0.828 Anlical gear having a helix angle of 23° and prescure angle of 20°. Find the pressure angle normal tothe teeth. ‘A. 0.235 B. 0.335 ©. 0.435 D. 0.535 AT hp motor, running at 450 rpm is geared to a pump by means of helical gear having a pinion dlameter of 8 in. Find the tangential force of the gear. ‘A. 2,326 Ibs B. 2,426 bs . 2,526 Ibs D. 2,626 Ibs ‘A turbine at 30,000 rpm is used to drive a reduction gear delivering 3 hp at 3,000 rpm. The gears are 20 degrees involute herringbone gears of 28 pitch and 2 1/8 in effective width. The pinion has 20 teeth with a helix angle of 23.deg. Determine the load normal to the tooth surface, ‘A. 204 Ibs B. 24.4 Ibs ©. 28.41bs D. 32.41bs ‘Anlical gear having 20 teeth and pitch diameter of Sin. Find the normal diametral pitch if helix angle is 22 A. 3.21 in B. 4.31 in ©. 5.31 in D. 6.31 in . helical gear tangential load of 200 Ibs and axal load of 73 Ibs. Find the helix angie. ‘A. 14 degroes: B. 16 degroes . 18 degrees: D. 20 degross ‘Anlical gear having 20 teeth and pitch diameter of Sin. Find the normal diametral pitch if helix angle is 22 degrees. A. 3.231 in B. 4.31 in ©. 5.31in ©. 6.31 in |. Two helical gear transmit 50 HP at 3600 rpm. What should be the bore diameter of each gear be ifthe allowable ‘stress in gear shafis is 12,500 psi? ‘A. 1.282 in B. 1.3275 in ©. 1.4568 in D. 1.5276 in31. 33. a 43, |. A 20° full depth straight tooth gear has a face width of 3 % in and a pitch diameter of 12 in with cone pitch angle of 37.5°. Find the mean diameter. A. 672in B. 7.72in C. 8.72in D. 9.72in A straight tooth bevel gear has a face width of 4” and a pitch diameter of 14 in with cone pitch angle of 40°. If the torque on the gear is 8000 in.lb, what is the tangential force on the gear? ‘A. 1400 Ibs B. 1400 Ibs C. 1400 Ibs D. 1400 Ibs A pair of straight tooth bevel gear connect a pair of shafts 90°. The velocity ratio is 3 to 1. What is the cone pitch ‘angle of smalllar gear? A. 71.57 deg B. 65.34 deg C. 18.43 deg D. 12.34 deg A spiral bevel pinion with a left-hand spiral rotates clockwise transmits power toa mating gear with speed ratio of 2to1. Determine the pitch angle of the pinion. A. 16.56 deg B. 20.56 deg C. 26.56 deg D. 22.56 deg |. A spiral bevel pinion with a left-hand spiral transmits 4 hp at 1200 rpm to a mating gear. The mean diameter of the pinion is 3 in. Find the tangential force at the mean radius of the gear. ‘A. 110 Ibs. B. 120Ibs C. 120 Ibs D. 140 Ibs. . A pair of 4-pitch, 14.5°, involute bevel gears have 2:1 reduction. The pitch diameter of the driver is 1 0 in and face width of 2 in. Determine the face angle of pinion. (Shafts at right angle) ‘A. 20.85 deg B. 23.85 deg C. 25.85 deg D. 27.85 deg . The cone angle of pinion of a pair of bevel gear is 30° while for the gear 60°. If the pinion tums at 300 rpm, find the speed of the gear. A. 173.21 rpm. B. 18321 1pm . 193.21 1pm D. 203.21 1pm The cone angle of pinion and the gear are 25° and 65° respectively. Find the speed ratio. A B.52 C. 4.23 D. 2.14 A pair of bevel gear having a speed ratio of 3 has a 5-pitch at 14.5 deg involute. The pitch angle of the pinion is Bin. Find the addendum angle of the pinion. (At right angle between shafts) BL 145° Cc. 2.34° ‘A. 0.906" D. 3.20° A pair of bevel gear having a speed ratio of 2 has 4-pitch at 14.5° involute. The pitch diameter of pinion is 7 in. Find the dedendum angle of the gear. ‘A 1.41 deg B. 2.11 dog ©. 3.41 deg D. 4.11 deg |. A class 3 pinion bevel gear is made of alloy steel hardened o 300 Brinell. The pinion runs at 850 rom with 5 in pitch diameter. Find the gear stress at factor of safety 3. A. 36,023 psi B. 45,023 psi C. 55,023 psi D. 65,023 psi ‘Compute the pitch angle of a bevel gear given the pinion’s number of teeth of 14 and 42 teath on the gear. A 184" B. 28.4" c. 33.4" D. 38.4" ln a standard bevel gear, the pinion rotates at 150 rpm, its number of teeth is 14 while the gear has 42 teeth, ‘what is the pitch angle of the pinion? A. 18.4 degrees B. 20 degrees C. 14.5 degrees D. 20.5 degrees ‘A four-wheel vehicle must develop a drawbar pull of 17,500 lbs. The engine which develops 500 hp and drives ‘500 hp and drives through a gear transmission a 34-tooth spiral bevel pinion gear which meshes with a spiral bevel gear having 51 teeth. This gear is keyed to the drive shaft of the 48 in diameter rear wheels of the vehidle. ‘What transmission gear ratio should be used if the engine develops maximum torque at 1500 rpm? Note: the efficiency of the bevel gear differential is 80%. ‘A. 17.493:1 B. 16.667:1 ©. 18.9622 D. 11.4922ANSWER KEY LA 6D 1.B 16.C 21.4 26.B 31.D 36. aA 2.0 TA 12.D 17.D 22.6 27.D 32.4 37.D 42.4 3.8 ac 13.4 18.4 23.B 28.B 33.C 38. 43.B 4c 9D 14.D 19.B 24.D 29.D 34.D 39.B 5.D 10.B 15.4 20.B 25.A 30.D 35.D 40.A