Elements in Machine Design (j.t.) Module 16

ELEMENTS IN MACHINE DESIGN (J.T.) – MODULE 16 1.

The larger of two interacting gears. a. Gear b. Hub c. Pinion d. Bevel 2. The smaller gear in a pair. a. Wheel b. Pinion c. Miter d. Rack 3. The path followed by the point of contact between two meshing gear teeth. a. Gear contact b. Angle of contact c. Contact me d. Path of contact 4. In spur gearing, another term for line of action is called: a. Gear action b. Pressure line c. Angle of action d. Center line 5. The line along which the force between two meshing gear teeth is directed. In general, it changes from moment to moment during the period of engagement of pair of teeth. a. Line of action b. Pressure angle c. Angle of contact d. Radial line 6. The axis of revolution of the gear or center line of the shaft. a. Pitch point b. Pitch line c. Axis d. Shaft line 7. The point where the line of action crosses a line joining the two gear axes. a. Gear point b. Pitch point c. Pitch surface d. Action line point 8. A circle, centered on and perpendicular to the axis, and passing through the pitch point. a. Pitch circle b. Diametral pitch c. Axial surface d. Center point 9. In spur gearing, another term for pitch circle is called: a. Diametral pitch b. Pitch diameter c. Line of action d. Pitch line 10. Diameter of a pitch circle and is equal to twice the perpendicular distance from the axis to the pitch point.

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a. Diametral pitch b. Perpendicular pitch c. Axial pitch d. Pitch diameter The module of a gear is equal to the pitch diameter divided by the number of teeth. a. Module b. Pitch diameter c. Diametral pitch d. Circular pitch The pitch diameter determined from the number of teeth and the center distance at which gears operate. a. Operating pitch diameter b. Operating diametral pitch c. Axial pitch diameters d. Radial vectors For cylindrical gears, this is the cylinder formed by projecting a pitch circle in the axial direction. a. Axial pitch b. Pitch surface c. Circular pitch d. Root cylinder Angle with vertex at the gear center, one leg on the point where mating teeth first make contact, the other leg on the point where they disengage. a. Center angle b. Vertical angle c. Angle of action d. Vertex action The segment of a pitch circle subtended by the angle of action. a. Angular force b. Pitch angle c. Angle of action d. Arc of action The complement of the angle between the direction that the teeth exert force on each other, and the line joining the centers of the two gears. a. Pitch angle b. Pressure angle c. Central angle d. Mating angle For involute gears, the teeth always exert force along the line of action, and thus, for involute gears, the pressure angle is: a. Constant b. Variable c. Fixed d. Equal Diameter of the gear, measured from the tops of the teeth. a. Outside diameter b. Pitch diameter c. Root diameter d. Base diameter

19. Diameter of the gear, measured from the base of the tooth space. a. Base diameter b. Root diameter c. Central diameter d. Tooth diameter 20. The radial distance from the pitch surface to the outer most point of the tooth. a. Addendum b. Dedendum c. Chord d. Tooth thickness 21. The radial distance from the depth of the tooth through to the pitch surface. a. Addendum b. Dedendum c. Chordal thickness d. Circular thickness 22. The total depth of a tooth space, equal to addendum plus dedendum, also equal to working depth plus clearance. a. Working depth b. Whole depth c. Tooth space d. Pitch surface 23. The distance between the root circle of a gear and the addendum circle of its mating gear. a. Backlash b. Root diameter c. Clearance d. Addendum 24. The depth of engagements of two gears, that is, the sum of their operating addendums. a. Working depth b. Whole depth c. Tooth depth d. Tooth thickness 25. The distance from one face of a tooth to the corresponding face of an adjacent tooth on the same gear, measured along the pitch circle. a. Pitch circle b. Circular pitch c. Diametral pitch d. Axial pitch 26. The ratio of the number of teeth to the pitch diameter. a. Pitch circle b. Circular pitch c. Diametral pitch d. Axial pitch 27. Applies only to involute gears, where the tooth profile is the involute of this circle. The circle is termed as a. Base circle b. Addendum circle c. Pitch circle d. Circular pitch

28. Applies only to involute gears. It is the distance from one face of a tooth to the corresponding face of an adjacent tooth on the same gear, measured along the base circle. a. Base pitch b. Addendum pitch c. Pitch circle d. Circular pitch 29. Contact between teeth other than at the intended parts of their surfaces. a. Interference b. Diametral tolerance c. Allowance d. Surface 30. The angle between a tangent to the helix and the gear axis. a. Helix angle b. Gear angle c. Axial angle d. Pitch angle 31. Circular pitch in the plane normal to the teeth. a. Radial circular pitch b. Base circular pitch c. Plane pitch d. Normal circular pitch 32. Circular pitch in the plane of rotation of the gear. a. Radial circular pitch b. Base circular pitch c. Transverse circular pitch d. Normal circular pitch 33. The distance from any point on a thread to the corresponding point on the next turn of the same thread, measured parallel to the axis. a. Pitch b. Lead c. No. Of threads per inch d. Lineal diametral pitch 34. The distance from any point on a thread to the corresponding point on the adjacent thread, measured parallel to the axis. a. Circular pitch b. Lead c. No. Of threads per inch d. Lineal pitch 35. The angle between a tangent to the helix and a plane perpendicular to the axis. a. Pitch angle b. Lead angle c. Plane angle d. Lineal angle 36. For involute gear, parallel-axis gears with either spur or helical teeth, is the rectangular area in the plane of action bounded by the length of action and the effective face width. a. Zone of action b. Path of action c. Length of action

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d. Involute action 37. It is the straight line passing through the pitch point and tangent to both base circles. a. Zone of action b. Plane of action c. Length of action d. Line of action 38. The imaginary surface in which contact occurs between two engaging tooth surfaces. a. Surface of action b. Plane of action c. Length of action d. Line of action 39. The distance of the line of action through which the point of contact moves during the action of the tooth profile. a. Length of action b. Plane of action c. Surface of action d. Arc of action 40. The arc of the pitch circle through which a tooth profile moves from the beginning to the end of contact with a mating profile. a. Length of action b. Plane of action c. Surface of action d. Arc of action 41. The arc of the pitch circle through which a tooth profile moves from its beginning of contact until the point of contact arrives at the pitch point. a. Length of action b. Arc of approach c. Arc of recess d. Arc of action 42. The arc of the pitch circle through which a tooth profile moves from contact at the pitch point until contact ends. a. Length of action b. Arc of approach c. Arc of recess d. Arc of action 43. The number of angular pitches through which a tooth surface rotates from the beginning to the end of contact. a. Pitch ratio b. Contact ratio c. Tooth ratio d. Speed ratio 44. The contact ratio in a transverse plane. It is the ratio of the angle of action to the angular pitch. a. Pitch ratio b. Transverse contact ratio c. Contact ratio d. Speed ratio 45. The contact ratio in an axial plane, or the ratio of the face width to the axial pitch. For bevel and hypoid gears it is the ratio of face advance to circular pitch. a. Pitch ratio b. Transverse contact ratio

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c. Face contact ratio d. Speed ratio The sum of the transverse contact ratio and the face contact ratio. a. Pitch ratio b. Transverse contact ratio c. Face contact ratio d. Total contact ratio For bevel gears is the square root of the sum of the squares of the transverse and face contact ratios. a. Modified contact ratio b. Transverse contact ratio c. Face contact ratio d. Square contact ratio The diameter on a gear at which the line of action intersects the maximum addendum circle of the mating gear. a. Maximum diameter b. Limit diameter c. Minimum diameter d. Pitch diameter The intersection of the limit diameter and the involute profile. a. The start of active profile b. The end of active profile c. The start of contact d. The end of contact The distance on a pitch circle through which a helical or spiral tooth moves from the position at which contact begins at one end of the tooth trace on the pitch surface to the position where contact ceases at the other end. a. Face advance b. Root advance c. Positioning d. Starting The error in motion that occurs when gears change direction. a. Backlash b. Tolerance c. Clearance d. All of these The curve of intersection of a tooth surface and a plane or surface normal to the pitch surface. a. Tooth space b. Tooth profile c. Pitch surface d. None of these The concave portion of the tooth profile where it joins the bottom of the tooth space. a. Tooth profile b. Tooth space c. Fillet curve d. Top curve Is a condition in generated gear teeth when any part of the fillet curve lies inside of a line drawn tangent to the working profile at its point of juncture with the fillet.

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a. Tooth profile cut b. Undercut c. Fillet cut d. Transverse point The distance between a point on one tooth and the corresponding point on an adjacent tooth. a. Pitch b. Diametral pitch c. Tooth line d. Chordal pitch The arc distance along a specified pitch circles or pitch line between corresponding profiles of adjacent teeth. a. Circular pitch b. Diametral pitch c. Tooth space d. Tooth line Normal circular pitch is the circular pitch in the normal plane, and also the length of the arc along the normal pitch helix between helical teeth or threads. a. Normal circular pitch b. Normal diametral pitch c. Normal pitch helix d. Helical tooth line The linear pitch in an axial plane and in a pitch surface. a. Axial pitch b. Lineal pitch c. Plane pitch d. Radial pitch The angle subtended by the circular pitch, usually expressed in radians. a. Circular pitch b. Angular pitch c. Radian pitch d. Arc pitch The length of arc between the two sides of a gear tooth, on the specified datum circle. a. Circular thickness b. Axial thickness c. Radial thickness d. Chordal thickness The circular thickness in the transverse plane. a. Normal circular thickness b. Axial thickness c. Radial thickness d. Transverse circular thickness The circular thickness in the normal plane. In a helical gear it may be considered as the length of arc along a normal helix. a. Normal circular thickness b. Axial circular thickness c. Radial thickness d. Transverse circular thickness In helical gears and worms is the tooth thickness in an axial cross section at the standard pitch diameter. a. Normal circular thickness b. Axial thickness

c. Radial thickness d. Transverse circular thickness 64. In involute teeth is the length of arc on the base circle between the two involute curves forming the profile of a tooth. a. Normal circular thickness b. Axial thickness c. Base circular thickness d. Transverse circular thickness 65. The length of the chord that subtends a circular thickness arc in the plane normal to the pitch helix. a. Normal circular thickness b. Axial thickness c. Chordal thickness d. Transverse circular thickness 66. The height from the top of the tooth to the chord subtending the circular thickness arc. a. Addendum b. Chordal addendum c. Axial addendum d. Total height 67. The displacement of the basic rack datum line from the reference cylinder, made non-dimensional by dividing by the normal module. a. Arc shift b. Speed shift c. Profile shift d. Angle shift 68. The displacement of the tool datum line from the reference cylinder, made non-dimensional by dividing by the normal module. a. Rack shift b. Speed shift c. Profile shift d. Angle shift 69. The measurement of the distance taken over a pin positioned in a tooth space and a reference surface. a. Measurement over pins b. Pin pitch c. Surface pitch d. Space pitch 70. The measurement of the distance across several teeth in a normal plane. a. Span measurement b. Length of arc c. Tooth length d. Normal length 71. Gears whose teeth have a working depth equal 2.000 divided by the normal diametral pitch. a. Stub teeth b. Normal teeth c. Full-depth teeth d. Long teeth 72. Gears whose teeth have a working depth is less than 2.000 divided by the normal diametral pitch. a. Stub teeth

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b. Normal teeth c. Full-depth teeth d. Long teeth Two engaging gears have equal addendums. a. Identical gears b. Miter gears c. Same teeth d. Equal addendum teeth A type of gear with the teeth formed on the outer surface of a cylinder or cone. a. Internal gear b. Hypoid gear c. Rack gear d. External gear A type of gear with the teeth formed on the inner surface of a cylinder or cone. a. Internal gear b. Hypoid gear c. Rack gear d. External gear The simplest and most common type of gear. Their general form is a cylinder or disk. The teeth project radially, and straight-cut gears. a. Spur gears b. Helical gears c. Worm gears d. Bevel gears A type of gear in which the teeth are not parallel to the axis of rotation, but are set at an angle. a. Spur gears b. Helical gears c. Worm gears d. Bevel gears A type of helical gear that is used to overcome the problem of axial thrust presented by ‘single’ helical gears by having teeth that set in a ‘V’ shape. a. Miter gears b. Herringbone gears c. Worm wheels d. Bevel gears Bevel gears with equal numbers of teeth and shaft axes at 90 degrees are called: a. Miter gears b. Herringbone gears c. Worm wheels d. Zero bevel gears A type of gears that are essentially conically shaped, although the actual gear does not extend all the way to the vertex of the cone that bounds it. a. Spur gears b. Helical gears c. Worm gears d. Bevel gears A type of bevel gear having teeth that are both curved along their length. a. Miter gears

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b. Herringbone gears c. Spiral bevel gears d. Zero bevel gears A type of bevel gear having teeth which are curved along their length, but not angled. a. Miter gears b. Herringbone gears c. Spiral bevel gears d. Zero bevel gears A particular form of bevel gear whose teeth project at right angles to the plane of the wheel. a. Miter gears b. Crown gears c. Spiral bevel gears d. Herringbone gears A gear that resemble spiral bevel gears, except that the shaft axes are offset, not intersecting. a. Bevel gear b. Worm gear c. Crown gear d. Hypoid gear A gear that resembles a screw. It is a species of helical gear, but its helix angle is usually somewhat large and its body is usually fairly long in the axial direction. a. Bevel gear b. Worm gear c. Crown gear d. Hypoid gear Helical gears are, in practice, limited to gear ratios of a. 10:1 and under b. 10:1 and over c. 100:1 and under d. 100:1 and over Worm gear sets commonly have gear ratios between a. 10:1 and 20:1 b. 10:1 and 100:1 c. 20:1 and 50:1 d. 20:1 and 40:1 A toothed bar or rod that can be thought of a sector gear with an infinitely large radius of curvature. a. Worm wheel b. Miter gear c. Rack gear d. Ring gear The type of gear used to connect shafts that are in the same plane and parallel. The teeth are cut straight and parallel to the axis of the shaft rotation. a. Spur gear b. Miter gear c. Wheel d. Bevel gear A type of gear used to change rotary motion to linear motion or linear motion to rotary motion. a. Worm and worm gear b. Bevel and spur c. Rack and pinion

d. Rack and bevel 91. Not enough backlash will cause early failure a. Due to overloading b. Heat due to improper lubrication and binding c. Fatigue of tooth surfaces d. All of these 92. When an external gear is meshed with an internal gear the gears will rotate in: a. Same direction b. Opposite direction c. Will not rotate d. None of the above 93. Refers to the surface of the gear between the fillets of adjacent teeth: a. Top land b. Bottom land c. Pitch d. Fillet 94. Effective face width of a helical gear divided by gear axial pitch. a. Face overlap b. Teeth overlap c. Land overlap d. Pitch overlap 95. The curve formed by the path of a point on a straight line as it rolls along a convex base curve. a. Involute b. Trochoid c. Cycloid d. Fillet 96. The curve formed by the path of a point on the extension of a circle as it rolls along a curved or line. a. Trochoid b. Involute c. Cycloid d. Undercut 97. Herringbone gears are gears which: a. Do not operate on parallel shafts b. Have a line contact between the teeth c. Consist of two left handed helical gears d. Tend to produce and trust on the shafts 98. Addendum of a cycloidal gear tooth is: a. Cycloid b. Straight rack c. Epicycloids d. Involute 99. For an evenly distributed and uniform wear on each meshing gear tooth, the ideal design practice is to consider a ___. a. Wear resistance alloy addition to tooth gears b. Heat treatment of the gears c. Hardening of each room d. Hunting tooth addition 100. In case of spur gears the flank of the tooth is: a. The part of the tooth surface lying below the pitch surface

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The curve forming face and flank The width of the gear tooth measured axially along the pitch surface The surface of the top of the tooth -

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