ProfileFα

Cf NfProfile deviation, total
Overlay of profile form deviationand profile slope deviation.

Lαgα

Cαa

Profile form deviation
Form deviation of the profile without
consideration of the slope deviation.

Cαf

Cαfp
gα

Cf Nf

Fa a2

3456

78910 11 12 13 14 15 16 17 18

Fp
Fpi 01574

1

1-2-4-8-7-8 -11 -12 -10 -7-2-3

Single pitch deviation
Greatest unsigned positional
deviation of all individual right (left)
flanks to the preceding right (left)
flank.

j 18n1122334456567788

9 10 11 12 13 14 15 16 17 18
9 10 11 12 13 14 15 16 17 18

fpfpi 3142-3 -30-3-2 -4

1-1-3-1

235-1+Lα

Profile tip relief
Correction of the profile throughmaterial removal on the tooth tip.
Avoids jamming with the matinggear under load.

fHαgα

CfFffu0LCαf, max

LαmLCαf, minLCαa, minFrFa

Cαf

Cαa
Lαf

Profile crowning
Correction of the profile throughconvex curvature over a defined rangeof the tooth height. Compensatesfor elastic deformations of the toothunder load.

LαCf Nf

Lαa

Fa aCαLαgα

HelixIFf

Root form circle

CfStart of profile evaluation

NfStart of active profile

FaTip form circle

aTipgαLength of path of contact

LαProfile evaluation length

LαfProfile root relief zone

LCαf

Length of profile root relief

LαmMiddle profile zone of unmodified profile

LαaProfile tip relief zone

LCαa

Length of profile tip relief

II

Helix deviation, total
Overlay of helix form deviation andhelix slope deviation.

Adjacent pitch differenceGreatest unsigned difference of all
individual single pitch deviations of
all right (left) flanks.

fufui 423250331252223126

Radial runoutaLCαa, maxfe

Radial runout deviation
Range of the radial positional
deviation of all gaps. Measured byplacing a measuring sphere on bothflanks of all gaps.

FriFr
fe

1

Eccentricity
Eccentricity of the gearing to thereference system axis (bore/shaft).

234

5678

9 10 11 12 13 14 15 16 17 18kDiameter
daFß1ffαProfile slope deviation
Slope deviation of the profile
without consideration of the formdeviation.

Profile root relief
Correction of the profile throughmaterial removal on the tooth root.
Avoids jamming with the matinggear under load.

j

Cumulative pitch deviation, total
Range of the positional deviationof all right (left) flanks to thenominal position, with the flanks
being analyzed independently.

FaLα

fHα

FpFα

Cf Nfffα

Pitch

Fadf
Fβ

Lβ

Tip circle diameter
Greatest (smallest) diameter of an
external gear (internal gear) at thetooth tip.

dadf

Root circle diameter
Smallest (greatest) diameter of an
external gear (internal gear) at thetooth root.

b

Helix form deviation
Form deviation of the helix without
consideration of the slope deviation.

III-Tooth thickness

ƒfβ+sLβb

fHß

Helix slope deviation
Slope deviation of the helix without
consideration of the form deviation.

III+

ƒHβ

MrK

Lβb

Helix end relief at datum face
Correction of the helix throughmaterial removal on the flank endsof the datum face. Avoids jammingwith the mating gear under load.

ILCI, max

LβmLCI, min

LCII, max

II

CβII
LβI

Helix end relief at non-datum
face
Correction of the helix throughmaterial removal on the flank endsof the non-datum face. Avoids
jamming with the mating gear
under load.

LβCß

Helix crowning
Correction of the helix throughconvex curvature over the face width.
Compensates for elastic deformationsof the tooth under load.

ZEISS Gear Metrology
www.zeiss.com

LβII

over/between two pins
Greatest outermost (smallest innermost)
distance of two defined measuring
spheres/pins (cylinder) fitted in two
opposing gaps on both flanks of an
external gear (internal gear).

bIIILβbCβ

Radial dimension
over/between one ballRadial distance of the gear axis to theoutermost (innermost) point of a definedmeasuring sphere fitted in a gap on bothflanks of an external gear (internal gear).

dimension
MdK Diametral
over/between two balls
MdR Diametral dimension

LCII, min

CβI

CßII

Sd0-CßI

Tooth thickness
Arc length of the distance of a rightto a left flank in a transverse section
plane on the reference diameter.

IDatum face

IINon-datum facebFace width

Lβ

Helix evaluation length

LβI

Helix end relief zone (datum face)

LCI

Length of helix end relief (datum face)Lβm

Middle helix zone of unmodified helix

LβII

Helix end relief zone (non-datum face)

LCII

Length of helix end relief (non-datum face)

Wk

Base tangent length overk teeth (gaps)
Distance of two parallel measuring planes
that intersect a right and left flank overk teeth (gaps) of an external gear (internalgear) and also lie in a tangential plane on
the base circle.

DMMrKDM

MdK / MdR

WkdBi

Individual value

jFlank numberkTooth/gap numbernPitch numberd

Reference diameterdB

Base diameter

DMDiameter of the measuring ball/pin (cylinder)

EN_60_050_0006I Printed in Germany. V/2015 © Carl Zeissffß