b. Pitch Diameter (PD)

g. Whole Depth (WD)2.15708

(1) Diameter of the pitch circle.

(1) The sum of an addendum and a

dedendum.

(2) For every tooth in the gear there is an

addendum on the pitch diameter.

(2) 1.0000 - ADD

(3) *ADD *× *NT = PD*

+1.1570 - DED

c. Outside Diameter (OD).

2.1570 - WD

(1) The diameter of the gear.

h. Diametral Pitch (DP)

(2) Since there is an addendum on the pitch

(1) The ratio of the number of teeth per inch

diameter for each tooth, the two elements are directly

of pitch diameter.

related. Therefore, the outside diameter is simply the

pitch diameter plus two addendums, or simulated teeth.

(2)

The formulas read:

i. Chordal Addendumac

(a) *ADD *× *NT = PD*

(1) The distance from the top of a gear tooth

(b) *ADD *× *(NT) + *2) *= OD*

to a chord subtending (extending under) the

intersections of the tooth thickness arc and the sides of

the tooth.

d. Linear Pitch (LP)

(1) The linear pitch is the same as the

(2)

circular pitch except that it is the lineal measurement of

pitch on a gear rack

j. Chordal Thicknesstc

(1) The thickness of the tooth, measured at

(3) Figure AIV-2 illustrates linear pitch.

the pitch circle.

SHIP

GEAR

TOOTH

2. GEAR ELEMENTS

a. PD

a ADD

a. Number of Teeth (NT)

b. OD

b. DED

(1) Connecting link between the tooth

c. CP

c. ac

elements and gear elements.

d. CT

d. tc

e. WD

(2) Number of teeth in the gear

f. CL

g. DP

(3)

AIV-2

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