MOMSP#8 (GEARS: Spur, Helical, Worm and Bevel) BASAEN, RG.

|
LINX ENGINEERING 4
~ INTERNATIONAL
Floor CMFF! Od Bidg., 815 R. Pape St. Sampatoc, Manila
Feu Nov/a6e6r0 too, Man

MACHINE DESIGN
(8.GEARS: Spur, Helical, Worm and Bevel}

Gry te
(Prepared by: Engr. Romulo Vicente D. Basaen)

b = face width Wr = atd —<

a= addendum distance
d= dedendum distance
WD: atd
q pA
a+d= whole depth +
2a = working depth =< 2QtC
c= clearance
= Wr +c
t, = tooth space or space width
t, = tooth thickness pe(te #4)

- ID -
P,= ciroular pitch

Rat +0} a

=e
Py= diametral pitch
A. SPUR GEARS
Reference:
DMM by Doughtie
DME by Faires

¢ Forces on a Gear Tooth

{Pitch circle

DJ Dp = pitch diameters
C. =center distance
Ft= tangential force

Re 2(Torgue)
D \, é
a
he
Fr= radial force or separating force

=F, tang Vr %
. cr}
FREresultant foree (bending load on shat) bpNe by + Strength of Gear Teeth
normal lo
Ceartter For ordinary industrial gears operating at velocities up to 2000

Fy =F +82)| Spe Ne hy som

Na, Ng = angular speeds Velonty palig

St oe |
Ss OY 600

m° — a
> P, (600+,
Nu, Ny = number of teeth of the gears, NeTp r Ng tg
- For accurately cut gears operating at velocities up to 4000 fon

KBr fg: p= Seb] _1200 ¢

it be. ty P, (1200+
. [—_

Mie Pg Ts
 1 up
For precision gears cut with a high degree of accurac MDMSP#8 (GEARS: Spur, Helical, Worm and Bevel} BASAEN, RG 2
y and

(1veJve) (ao S|
operating at velocities af 4000 fom and over -
we er

_S,o¥| 78 ff
Ain
= Ve 2 E+)
2 2

33100
L
‘PB, 784 fv, F, _ Power |Z
where — \
Ft = tangential load or transmitted toad Vn
<= \
= oO . 3 Wp
Fo=F
F, =r
Power pr TL Vin

Ym _¢ — Fo= FE, tan ¢ e

Va = pitch line velocity; y=nDN
5, = safe working stress or design stress
tan ¢, = tandcos
. (fablel3)
Y = Lewis form factor (Table 1 1-2) :
Py=diametral pitch [P.. = P, cosy} normal circular pitch
b= face width

* Dynamic Load on Gear Teeth

7 7.
v, os Xe Z a“
0,05v_
Fy =F, + F, = F 4205 (Ch + F.
(Ch+ Fi) ¢ 0f
Lf
0.05, +JCb +h
: ¥ vn
where
Fa= total equivalent load applied at pitch line of Oe,
F, = tangential toad : 44 Pa
F, = increment load (variable load) Ss
C=a factor dependent upon mach ining errors
b= face width (a) (b) .
(Circular pitch) (Axial pitch)
B. HELICAL GEARS
¢ | Strength of Helical Gear Feeth

¥’ = form factor based On the virtual number of

teeth

Te
t=
¥
—_ cos’y
Ft= tangential load
Sw = safe working stress
b= face width
Pd = diametra! piteh

¢ Dynamic Load on Gear Teeth

ue
Fy= F+h=F4 0.05v, (Cbcos 2
+k cosy

¢
(3)
Forces on @ Gear Tooth
% o 0.05y, +/Cbcos” y+ F. a

(Use Table 11-5 and 11-6, DMAF by D&Y,fr Q

n FL Ft
F a* i’ \ {en 4
y: fa
F, = tangential force
F,= radial f - any
F,= xia! force Fae Ft
Fa = resultant force
v= helix angle
$= pressure angle
$.= normal pressure angte
 ‘MOMSP#8 (GEARS: Spur, Helical, Worm and Bevel) BASAEN, RG
3
C, WORM GEARS +. Tangential Force on Worm

wore ge"
is
[| 2(Torque,.)
7 D,
ey
* Tangential Force on the Gear *

f, =a ; © =efficiency

* Separating Force between Worm and Gear

. Worm gear drive. .

(a) single enveloping (cylindrical teeth); (b) double
s-__. Fising,
— — enveloping. cosg, co—sd
fsin A
Ff ra °

f= coefficient of friction between surfaces

¢ Speed Ratio HW ty = "9 Ty

Ni? no. of teeth of gear _t4

N, no. of threads of worm T,'-l-2-%
where
Tw=i fora Single-threaded worm
Tw =2 for a double-threaded wonn
Tw =3 for a triple-threaded worm

¢ — Strength of the Gear (Gear is weaker than worm)

*
” -wF
Important Angies on the Gear Teeth
re S,bY 1200

tn( 2) _ tang, ‘RP, [1200+y,

2 tan A
,
oy where
= fa Ie (usually 60° P,~ circular pitch of gear
A tead atl (osvally 60) Ps = diameteral pitch of gear
$, = normal pressure angle (cPd=n)
$= pressure angle y Y = form factor (Table 1 1-2, DEV)

i=g
tape}
Vg pitch line velocity of gear, fpm
b= face width

_ Lead D, BEVEL GEARS

tanA
=

Dw = pitch diameter of worm

Dg = pitch diameter of pear

+ = Efficiency of Werm and Gear

_ tanA(cos¢, — f tan 4)
é
__ (cosg, tan d+ f)
f= coefficient of friction between thethrea
ds

To maxithe
mi effi
zeciency,{tanA =yl+/? -f 7
* Power Input te the Worm

Torque transmitted by
worn
 MOMSP#8 (GEARS: Spur, Helical, Worm and Bevel) BASAEN,
where RG 4
IO
b= face width EEE

@=shaft angle
SO GEARS
= cone angle GAT
F, = tangential forge on ihe gear L A wheel with teeth cut parallel with the axis of
R = base radius rotation
D = base diameter Spur Gear
N= angular speed B. Bevel Gear
C. Worm Gear
¢ Torque Transmitted by Gear D. Helical Gear
Gear used to change rotary motion to reciprocating
motion.
A. Helical gear
Rack gear
C. Worm gear
D. Spur gear
This is the circle that bounds the outer ends of the gear
teeth,
A. Pitch Circle
B. — Working Depth circle
C. = Dedendum circle
' Addendum Circle
Tooth space minus the circular thickness of a spur
F, = tangential force gear. :
F, = axial force @ Backlash
F, = radial force Clearance
F, = resultant force

paw
face width
F, = F,(tang, cos 7| » Chordal thickness
What will be the effect in meshing gears without
‘backlash?
[F, = Ff, (tang,)siny A. jamming
B. overheating
C, overloading
Fp=yF24F 48? @ all ofthese
- The concave portion of the tooth profile where it foins
the bottom of the tooth space of a gear.
y Fillet curve
[tan¢, s tan peosy|- . Flank
C. Chordal Addendum
D. Land
4. = normal pressure angle For mating gears, this is the dedendum minus the
mating addendum .
* Strength of Gear Teeth A. backlash
clearance
FadebY lb . chordal thickiless
78 D. face widih
‘LL 32h 78+ fy, Afillet is used fn gears to:
A. increase the wear resistance
CB reduce stress concentration
where C. decrease the backlash
Sw = safe working stress D. reduce the circumferential pitch
b= face width ’ The height of tooth ebove the pitch circle or the
radial
Y = form factor (Table 1 1-2, DEV) distance between the pitch circle and the top land
of
Vm = nDN = 2nRN the teoth.
A. top root
+ = Spiral Bevel Gears addendum
C. land
D, hunting teoth
10. In an involute teeth, the pressure angle is often defined
Wom as the angle between the line of action and the
line
tangent to the pitch circle. It is also termed as the:
A. helix angle
B. angle of recess
a Cl Spirvid angle of obliquity
D, are of action
- The point of tangency of the pitch circles
Ring Gear ser EE of meshing
gears, For an indiyidva! gear, this point
° i] Hypoid where the tooth profile cuts the standard pitch
is iocated
circle,
A. Addendum point
t=] Spiral Pitch point
C. Whole depth
D. Working depth
- The path of contact in involute pears where
force or
power is actually transmitted, It is a straight imagin
ary
line passing through the pitch point and tangen
t to the
base circle.
A. principal reference plane
B. front angle
C. Pitch point
) line of action
 = (200 rpm
TN
MOMSP#8 (GEARS: Spur, Helical, Worm and Bevel) BASAEN, .
13, The reciprocal ofa diametral piich or the
pitch diameter in mm to the na:of teeth.
ratio of the 26, A spur
RG
pinion rotates at 1800 rpm and transmits to a Mo. P ©3025
A. lead mating gear 30 hp. The pitch diameter is 4” and
the °9 = 30 yp
> ain ,
B. involute angle of obliquity is 14 v’, Determine the tangenti
al t: P(6302£ )
modula force on the gear in Jb,
D. clearance 525
i4. In gear design, the ratio of the pitch B. 543 = 4 f£ 7
diameter in inches H
fo the number of teeth C. 534
A. module
B, diametrical pitch 27,
D. 552
The usual range of helix angles on helical gears: fy. ?
English Module A. less than 18
D. circular pitch 15-25 . ay -
‘
Me
15. The ratio of the length of action to the
base pitch,
C. 20-35
A, Velocity of ratio
CB? Contact ratio 28.
D, 35-40
The hardness of helical and herringbone gear
testh 34. Y + 30
€.
D.
Recess ratio
Obliquity ratio
‘
+
after heat treatment is 210 to 300 Brinell hardness for
the gear and for the pinion.
Fi 2 P(e3oze ) P.. ~ os i
16. “Good proportions for the face width of spur gears in A. 380 Brinell, min
terms of the circula r pitch P,. @ 340-350 nomnally
400 Brineli,max
»
DN
A. 5Pe<b<4 Po
CH? 2.5Po<h<APg D. all ofthe above
Tp + iC
C. 1 Pe<b<15Pc 29. Commonly used in parallel shaft transmi
ssion
2 (oe We DSR )}:3
especially when a smooth continuous
czoee ) ‘
Tg: 48
D. 1.25Pe<b<3,25Pe
17. Curves that satisfy the law of gearing
are called:
action is
essential as in high speed drives up to 12,000 fpm
' Fe:
(4 md (1000 pe)
A. spiroid curves A. bevel gear
B. Fillet curves B. spur gear
conjugate curves © herring bone gear
D. pyroid curves
18. The curve formed by the path ofa 30.
D, helical gear
A pair of meshing helical gears has a diametr +9+Tp
tzs .2| Ibs
point on a circie as al pitch

ye
it rolis along a straght line. of 5 and a normal circular pitch of 0.35 in. Determi
ne
the helix angte,
2PdA-
A. Trochoid
CB? Cycloid AL 26,59° B. 20.61°
C. Root Circle C. 24,719 28.9°
D. Are of approach 31, Two mesbing helical Bears have a 30° helix
angle and
19. It is recommended to apply whenever a 0.5” normal circular pitch, The number
possible the use --15 and 43 teeth. Determine the center distan
of teeth are
of six (6) arms for pears up to 10 feet in
30) Pai - £ mW.
diameter and ce.
A. 261 in, B. 6.42 in,
for larger
A.
diameters, use:
7 pairs or more C420 in, CD? 5.513 in,
° Foy = Pecos Y
B. 14 32. A 250 mm diameter helicat gear has a 20°
involute F =0O-S¢ {n-
CQ
BD. 10 or more
8ormore stub tooth and a helix angle of 30°. Deter
mine:
8) the tangential and radial component
Fen =O yl’ Fe cos 3d°
gz. SR=.3°
20. For an even distribution tooth load in the plane of rotation of
and uniform wear on each
meshing gear teeth, the ideal transmitted at 1200 rpm
if 30 KW is
Pons Pe cos)
0.773
design practice is to
consider a
A. wear resistant alloy gears
b). the axial component of tooth toad
¢) the resultant tooth load, and Cos orn. or eo W Fe - | IN.
Ig=
B. heat treatment of the gears d) the angle of obliquity in the plane norma
C. hardening or each tooth to the pitch element of the tooth l
Go Fen “pd
@ hunting tooth addition (4c 4 ie ) -c¥¢f
Pe. 7 "
“aus, 1909.8 N, 695 N, 1102.62 N,
21, Find the tooth thickness on the Pitch
degree full depth tooth of 12 diame
circle of a 1 4%
trat pitch
—
“17.52
2312 N,
pce
= TM day Coe oN ——
A. 0.3208 inch @nu4.g tiadge 33. A worm gear consists of a worm
° with a triple thread Per ea
B, 0.5623 inch driving a worm wheel with 48 teeth Wy = 2e-E9 8
C. declh which is attached
1,309 inch Pde ie a. fe
fee tte"
MU Pe
to a 24 inches pulley, The worm is drive
n at 900 rpm.
2 3.em3)
CD. 90.4309 inch - Find the speed of the wonn wheel.
22. . te fd 2te
A gear set having a gear ratio
of3 is to be used ata ter A. 300rpm eps 4 Ts 19#TP
center distance of 10 laches. If
the gear has 60 t eeth, —tL CB 56.25 pm (Pe)
what must be the circular pitch, in inch? 2Pd C. 80.75 rpm
A. 6.7236 za, * D, 600mm 2fd - 27
0.7854 8Cre) 34, A triple-threaded worm has a Pitch
diameter of 4

23.
C.
D. 0.7283
0.8970
Find the tooth thickness of a’gea
tr 1309 inches, The wheel has 36 teeth and
inches. Compute the lead angle,
a pitch diameter of
9 3
Tp t
r if it has a diametral 118°

one
pitch of 4, B. 12.8°
A. 0.3297 Per
C.
0.3937
0.3397
2 t
{> Cc
dD.
14.3°
16.5°
te t) 2 A wom gear transmits 7,5 kW Go | Tp = 20 teal
D. 0.3957 wee tiple threaded worn has a pitch
at 1200 rpm., The
24, An internal gear is set up with diameter of 70 mm, 3 Sy
a Sin diameter pinion 4 The gear has 60 teeth which
at a center distance of £8 inche cut as 20° stub with a
s, Find the diameter of = circular pitch of 19 tum. The coefficient offriction’i
the annular gear, s
0.10. For a ripht-handed worn,
~~ A 38" Dp: & IA. ep: 09-De calculate:
B. 21,5” 2 un
A. speed ratio ans, 20:1
2 B, speed of worm gear ans. 60 rpm
C. 26” Cosh n
41” ? Woe 24-5 In
©, tangential foree on the worm
45. A machinist mad 8 diametrical pitch spur pears ang. 1705.23 N
to be mounted at a ceater distance of 10 2 D. tangential; force on the gear
inches with a
OO Speed ratlo
each gen.
of7 to 9, Determine the number of teeth in
;
8 and 3 x
g
Dg = 4
—
————
mM.
. resu sana
_ ae. 4540 N
Frredial orscparafing force sas, 1699.2N
N
Bh 1 10 and 8 PA
. ais.
ft
& Wand CD = fo
!
cD: T9At
T
es
4 G. efficiency of worm gear drive
Tg = = (ho)
D. 144 and 112 tas 69.01%
Se: : 7-9
. e

ade -——_
Te aT: ip Nn Tp - fo +]
9: ? 1, je co 2 ( )
Tp: ° 9 Tg
 MDMSP#8 (GEARS: Spur, Helical, Worm and Bevel) BASAEN, RG
36, Gears used to connect intersecting shafls that are 48, When an external gear is In mesh with an intemal
usually but not necessarily at 90° apart, gear, the gears will rotate in:
A. Spur Gears
Bevel gears
fi. same direction
B, opposite direction
e Worm Gears C, any direction
D. helical gears
D. none of the above
37. A pair of straight-tooth bevel gears are mounted on 49, The actual torque ratio of a gear set divided by its gear
shafts that intersect each other at an anple of 70°. The
ratio, :
velocity ratio is 4, Determine the pitch angle of the
A. clearance
pinion.
A. 48,14° 218° —B, efficiency
C. contact ratio
Cc. 184° » 18,2 D. approach ratio
38, A pair of straight-tooth bevel pears has a velocity ratio
30, If the driving gear has 20 teeth and rotates at 80 rpm
of 4:3, The pitch diameter of the pinion is 159 tam,
and the driven gear has 40 teeth, find the speed of the
The face width is 50 mm. The pinion rotates at 240
driven gear, in rpm.
tpm. The pressure angle is 14°, If6 KW is transmitted,
A. 40
detennine:
B. 20
8) the tangential foree on the pinion.
C. 56,57
b) the pinion thrust force D. 160
¢) the gear thrust force SL. Find the tooth thickness, in inch, of a gear whose
3183 N, 381N, 508N diametrical pitch is 5.
39, The axes of these gears are nonparallel and
nonintersecting and the teeth are straight. What type of
A. 0.34116 in
B OB4I6 in
bevel gears are these?
C. ' 0.32416
in
A. Hypoid gears
D. 0.31164 in
B. Spiral Bevel gears 52, A 3¢-in diameter pinion at 300 rpm drives a gear of
Skew Bevel gear 120-in diameter. The pressure angle is 14,5°,
D, Zerol Bevel gears
Determine the speed of the driven gear.
A. 1,0005pm
Miscellaneous Problems B. 800rpm
40. When two gears are in mesh, the smaller gear is C. 90rpm
called: D, 80pm
4. pinion 53 Find the center distance between gears with 50 tecth
B. —involute gear and 25 tecth if the diametral pitch is 5.
C. -Hypoid Gear A 5
D. —Spyrofd Gear B. 10
AL This is addendum plus dedendum. Cc. 85
~4._, whole depth D FS Co
B. working depth 54, A 30 In diameter pinion rotates at 300 mpm drives a
C. circular thickness gear of 120-in. diameter. The pressure angle is 14 4,
D. circular pitch Determine the rpm of the gear,
42, The surface of the teeth between the pitch and root A. 100zpm
cylinders ef a spur gear, B. 200rpm
AL flank Cc. 7Sipm ¥
B. face D. 801mm
C. pitot cylinder 35. A gcar having 60 teeth is driven by a 12-tooth gear
D, bottom land turning at 800 rpm,
43, The emount by which the width of a tooth space 3) What is the speed of the driven gear? Ans, 160 pm
exceeds the thickness of the engaging tooth along the 5) What would be the speed of the driven gear ifa 24-
pitch circle tooth idler were placed between the driving and the
AL Backlash driven gears? Ans, 160 rpm
B, clearance c) What would be the speed of the driven gear if two
C. Undercut . idlers were used? Ans, 160rpm
D. chordal thickness
. This refers to the surfaces of a gear between the fillets 56. A machine shop somewhere in Makati fabricated a
of its adjacent teeth, pair of spur gears with 2.5 module which are to be
A. Top land mounted on shafts at a center distance of 90 mm. The
3. Botton land speed ratio is 3:1. Determine thefollowing:
Cc. Pitch a) Pitch diameters Ans. 45 mm 135 mm
D. Fillet b) Number of teeth Ans 18 teeth, 54 teeth
45, The distance ofa gear icoth, which is equal to ¢) Circular pitch == Ans, 7.854. mm
the
sum of the addendum and the dedendum distances,
A. fulidepth 57 A Mitsubishi car transmission has two meshing spur
B. whole depth gears having a velocity ratio of about 1.4 The number
“C working depth of teeth in the driven gear is 36 and the diametral pitch
D. dedendum is 3.
46. The surface of the tooth between the pitch circle a) Determine the number of teeth in driver
and
the root cylinder of.a spur gear. b) Determine the distance between centers
A. Face width 0} What is the clreular pitch?
B. top fand Ans: 26 teeth, 10.4 in, 1.05 in
, flank
D,__ bettom land 38, A pinion and gear pair is carefully cut with a 20
47, The reciprocal of the diametral Pitch or the ratio degree full depth design. The 16-tooth steel pinion
of the and
pitch diameter to the number of tecth of a gear. the 72-tooth cast-iron gear transmit a power of
AL lead 50 kW
when the pinion tums at 1400 rpm. The face width
2B. module fs
90 mm and the module is 8, Find the center distance
C. involute ,
in mm, between pinion and gear and the compon
D, clearance ents
of the tooth force,
(Center distance, Tangential load, radial load:
352 mm, 5328.7 N, 1939.5 N)
 MDMSP#8 (GEARS: Spur, Helical, Worm and Bevel) BASAEN, RG
59. A pinion, rotating at 1800 rpm and is supported on 71. A pair of meshing gears has a diametral pitch of 10,
each side by ball bearings, transmits 18 kW to a a center distance of 2.6” and a velocity ratio of 1.6,
mating spur gear, Add 3° to the pressure angle to Determine the aumber of teeth of the smailer gear.
compensate for the friction. If the pressure angle is A 15 B. 18
20° and the pinion’s pitch diameter is 102mm, Cc. 20 D, 25
determine the following: 72. A spur gear with 20°FD involute teeth has an outside
a) the tangential tooth load; ans.1872.4N diameter of 195 mm and a module of 6.5. Determine
b) the foad which tends to separate the two the number of teeth.
gears; ans, 794,78 N A. 28 B. 30
c) the resultant load of the gear; Cc. 32 D 34
ans, 2034,10N 73. What is the pitch diameter of a 40-tooth spur gear
having a circular pitch of 0.7854” and a pitch line
60. The helical and herringbone gear teeth cut after heat velocity of 12 fps?
treatment should have a hardness in the range of | A. 8in. B. J0in.
210/300 BHN. The pinion gear teeth hardness on the Cc. 12in. D. 14 in.
other hand, ideally or normally should be et 74, At what rpm is a spur gear tuming if it has a module
BHN , of 2mm, number of teeth of 40, and a pitch line
. A. 250/320 velocity of 2.5m/s?
B. 400 A. 698.5 B. 856.9
C. 350/380 C. $968 - D. 965.8
D. 340/350 75. A standard 20°full depth spur gear has 24 teeth and a
61, A helical gear has a helix angle of 25° and a transverse circular pitch of 0.7854”, Determine the working
clreular pitch of 7/3 inch. Determine its normal depth.
circular pitch. A. 0.25 in. B. 0.75 in.
A. O569 B. 0.321 C. Osi D. 1.0in.
C, 0.485 D. 0.244 76, What is the equivalent diametral pitch of a gear that
62, A double-threaded, right-handed worm gear transmits has a module of 2.57
15 hp at 1150 rpm, The pitch of the worm is 0.75 inch A, 10.16 B. TL61
and its pitch diameter is 3 inches, The pressure angle Cc. 16,10 DB. 42,30
is 14.5° and the prevalling coefficient of friction is 77. A 20° full depth gear has a tooth thickness of 6.25”.
0.12. Find the tangential force on the gear in Ib, Find the addendum distance.
A. 1898 1b A. 0,195" B. 0.591°
B. 1989 lb C. 0.972" D. 6459”
C. 1867 ib 78. A 14,5°full depth gear has a tooth thickness of 0.25”,
D. 2675 tb find the addendum distance,
A. 0.212" B. 0,316"
63. This is a type ofa bevel gear with a variable angle of C. @459" D. 0.195"
contact and slope, 79. A gear has a pitch diameter of 10 inches and a
A. cyclold gear diametral pitch of 5. Determine the outside diameter,
B. helical gear A. 14.0 in. ‘ B. 125 in.
L hypoidgear Cc. l4in D. 13.6 in,
D. angled gear 80. A 14.5° full-depth gear has an addendum of 0.2".
64. Bevel gears subjected to corrosion and are lightly Determine the tooth space.
loaded are usually made of A. 0.4123" B. 0.3142”
A. bronze Cc. 0.2314" BD. 0.2413”
B. duralumin 81. An intermafly meshing gear bas a center distance of 20
C. brass inches, If the larger gear has a diameter of 50 inches,
D. all of these find the diameter of the internal gear.
65. A bével gear pair has a pinion of 12 teeth and a gear of A. Sin. B. /0in.
48 teeth. Determine the pitch angle of the gear. Cc. 12in. BD Min.
A. 1261° B. 36.42° 82. A 10-inch diameter gear is used to transmit 20 KW at
C, = 75.96° D. 60.41° 900 rpm. Determine the tangential force acting at each
gear,
A. LIT6kKN B. L617kN
Other Gear Problems C. L671 kN D. L7L6KN
66. Find the distance between the centers of a pair of 83. A 200mm diameter, 14.5° involute gear, is used to
gears, one of which has 12 teeth and the other 37 transmit 40 KW at 600 rpm. Determine the tangential
teeth. The diametral pitch is 7. ‘ force transmitted on the gear,
A iin B. 65 in. A. 6.366kN B. 3.666 KN
G 35in D. 7.5in, C. 9.423 KN D. 4,923 kN
67. Determine the pitch diameter of a 4-pitch gear with 28
teeth,
A 7 in B, 75in.
Cc Sin D. 8.5in
68. Two parallel shafts have an angular velocity ratio of 3
to 1 and are connected by gears, the larger of which
has 36 teeth. Find the number of teeth of the smaller
pear.
A ll ' Bo 22
Cc, 15 D, 16
69, Two parallel shafts have a center distance of 5
inches. One of the shafts carries a 40-tooth, 2-
diametral pitch gear, which drives a gear on the other
shaft at a speed of 150 mpm. How fast is the 40-tooth
gear turning?
A. 1001pm B. 1251pm
C. 75rpm D. 150 mpm
70. A 14,5°FD, involute gear has an outside diameter of
8.5inches and a diametral pitch of 4. Find the number
of testh.
A 30 B. 25
Cc, 35 DB. 32