Gears Encyclopedia

Gears Encyclopedia

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a Gear Term

Definitions of Gear Terms can be mystifying at the best of times. Gear formula and their calculation even more so.
In this section I hope to shine some light in this area and explain the calculation where applicable.
I will be adding and updating Gear Terms with pictures and animation's on a regular basis.
Please be patient as it is an ongoing project.
If you cannot find the gear term you require, why not make a request and I will bring it to the top of the pile.

A	If the term you are looking for is not here - 'Request a Term'
Active Profile Addendum Addendum Modification Addendum Modification Coefficient AGMA (American Gear Manufacturers Association) ANSI (American National Standards Institute) Approach Ratio Arc of Action Arc of Approach Arc of Recess Arcoid ASME (American Society of Mechanical Engineers) Axial Hobbing Axial Pitch ..... Axial Pitch Tolerance ..... Axial Pitch Variation Axial Plane Axial Runout Axial Thrust
B
Backlash ..... Minimum Backlash ..... Maximum Backlash ..... Backlash Tolerance ..... Backlash Variation Ball Diameter - see Pin Diameter Base Circle Diameter Base Helix Angle Base Pitch Base Tangent Basic Rack Profile Bevel Gears BGA - British Gear Association
C
Central Plane Centre Distance Change Factor Chordal Addendum Chordal Thickness Circular Pitch Circular Thickness Clearance Contact Diameter Contact Ratio
D
Dedendum Diametral Pitch
E
Effective Face Width Efficiency, Gear External Gear Extrusion
F
Face Of Tooth Fillet Curve Fillet Radius Fillet Stress Flank Of Tooth Form Diameter
G
Gashes - see Hob Flutes Gear Deviations ..... Pitch Deviations ..... ..... Single Pitch Deviations ..... ..... ..... Single pitch deviation f_pt ..... ..... ..... Normal pitch deviation f_pn ..... ..... ..... Base pitch deviation f_pb ..... ..... ..... Mean base pitch deviation f_pbm ..... ..... ..... Adjacent Pitch Difference f_u ..... ..... Cumulative Pitch Deviations ..... ..... ..... Cumulative pitch deviation F_pk ..... ..... ..... Total cumulative pitch deviation F_p ..... ..... ..... Pitch sector deviation f_pS ..... ..... ..... Cumulative pitch sector deviation F_pkS ..... ..... ..... Total cumulative pitch sector deviation Fps ..... Flank Deviations ..... ..... Profile deviations ..... ..... ..... Total profile deviation F_a ..... ..... ..... Profile slope deviation f_Ha ..... ..... ..... Profile form deviation f_fa ..... ..... ..... Base diameter deviation f_db and pressure angle deviation FA ..... ..... ..... Profile undulation f_wa ..... ..... Helix Deviations ..... ..... ..... Total helix deviation F_b ..... ..... ..... Helix slope deviation f_Hb ..... ..... ..... Helix form deviation f_fb ..... ..... ..... Helix angle deviation f_b ..... ..... ..... Helix undulation f_wb ..... ..... Generator Deviations ..... Runout, Eccentricity and Wobble ..... ..... Runout F_r ..... ..... Eccentricity f_e (f_eL, f_eR) ..... ..... Wobble F_s (F_sL, F_sR) ..... Tooth Thickness and Span Accuracy ..... ..... Tolerance on tooth thickness ..... ..... Tolerance on span ..... Composite Deviations ..... ..... Tangential composite deviations ..... ..... ..... Total tangential composite deviation F_i' ..... ..... Radial composite deviations ..... ..... ..... Total radial composite deviation F_i" ..... ..... ..... Tooth-to-tooth radial composite deviation f_i" ..... Gear Pair Deviations ..... ..... Centre distance deviation FA ..... ..... Parallel deviation of axes f_S ..... ..... Shaft inclination f_Ss ..... ..... Shaft skew f_Sb ..... ..... Composite deviations of gear pairs Gear Ratio Gear Tooth Vernier
H
Helical Overlap Helix Angle Hob - Flutes Gashes Hob - Runout Hobbing Machine HPSTC Highest Point Of Single Tooth Contact
I
Internal Diameter Internal Gear Involute
J

K

L
Land Lead .......... Lead Tolerance .......... Lead Variation Line Balancing and Motion Economy Line of Action
M
Module
N
Normal Module see Module
O

P
Pin Diameter - EXTERNAL Gears. (DOW, DOP, MOW, MOP) .......... Calculation of pin/ball diameter for EXTERNAL gears. .......... Calculation of the measurement over pins/balls for EXTERNAL gears. Pin Diameter - INTERNAL Gears. (DOW, DOP, MOW, MOP) .......... Calculation of pin/ball diameter for INTERNAL gears. .......... Calculation of the measurement between pins/balls for INTERNAL gears. Pitch .......... Pitch Range .......... Pitch-Range Tolerance .......... Pitch Tolerance .......... Pitch Variation Pitch Circle Pitch Diameter Pitch Plane Pitch Point Plane of Rotation Pressure Angle .......... Transverse Pressure Angle .......... Working Transverse Pressure Angle Principal Reference Planes Profile Shift Coefficient - see Addendum Modification Coefficient
Q

R
Rack Radial Hobbing Radial Runout Reference Diameter Roll Angle Root Circle Root Diameter
S
SAP - Start of Active Profile Shot Peening South Pointing Chariot Spur Gear Symbols and terms A to D: in English with German, French and Italian translations. .................................... E to M .................................... N to R .................................... S to Z
T
Tangent Plane TIF True Involute Form Diameter Tip Diameter Tip Relief Total Face Width Transverse Module see Module Translations of Gear Terms to German, French and Italian. Transverse Plane Trochoid
U
Undercut
V
Vernier - Gear Tooth
W
Working Depth
X

Y

Z

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