Gears

Question 1

Module

Answer 1

m = p / n (= d / n)

Question 2

Face width

Answer 2

ba = x m

where x = 9~15

Question 3

Circular tooth thickness

Answer 3

ctt = 1/2 p

Question 4

Outside tip diam.

Answer 4

da = dp/g + 2m

Question 5

Cicular pitch with m

Answer 5

p = pi m

Question 6

Centre distance

Answer 6

a = 1/2 (dg + dp)

Question 7

Tangential comp. force

Answer 7

Ft = F (cos α)

Question 8

What is α

Answer 8

Pressure angle

Question 9

Normal comp. force is aka

Answer 9

Separating

Question 10

Separating force

Answer 10

Fs = Ft (tan α)

Question 11

Relationship of rpm and rad/s

Answer 11

N1 / N2 = ω1 / ω2 (same way round)

Question 12

Relationship of rpms and diams.

Answer 12

N1 / N2 = d2 / d1 (flipped)

Question 13

Relationship of rpm and num. of teeth

Answer 13

N1 / N2 = z2 / z1 (flipped)

Question 14

Relationship of rad/s and num. of teeth

Answer 14

ω1 / ω2 = z2 / z1 (flipped)

Question 15

Power transmitted with torque

Answer 15

P1 = T1 ω1

Question 16

Power transmitted with torque, with efficiency

Answer 16

P1 = η T1 ω1

Question 17

Torque with Ft, with diam. or rad.

Answer 17

T1 = 1/2 (Ft d1) = Ft r1

Question 18

Transmitted load

Answer 18

Wt = P / V

Question 19

Pitch line velocity

Answer 19

V = 1/2 d ω

Question 19

Transmitted load using overload factor

Answer 19

Wt = (P / V) * (O.L. factor)

Question 20

Velocity factor

Where to find this

Answer 20

Kv = (x + V) / x

Formula sheet

Question 21

x in velocity factor eqs for a milled cut gears

Answer 21

6.1 (formula sheet)

Question 22

x in velocity factor eqs for a cast gears

Answer 22

3.05 (formula sheet)

Question 23

Lewis Eqs

on formula sheet

Answer 23

σ = Ft / (ba m Y)

Question 24

What to do to Lewis eqs if you have a velocity factor

formula sheet

Answer 24

σ = (Kv Ft) / (ba m Y)

Question 25

Y in Lewis eqs

Answer 25

Lewis form factor

Question 26

Contact ratio eqs

Answer 26

= [ (rgo^2 - rgb^2)^1/2 + (rpo^2 - rpb^2)^1/2 - a sinΦ ] / (pi m cosΦ)