Table of Contents

2
Special Characteristics, Points of Caution
in Selecting and Using Helical Gears.................... page 130
KHG Ground Helical Gears................................... page 134
SH Helical Gears.................................................. page 144

Catalog Number of KHK Stock Gears

The Catalog Number for KHK stock gears is based on the
simple formula listed below.
Please order KHK gears by specifying the Catalog Numbers.

(Example)
Helical Gears Helical Gears
K HG 1 - 20 R

Direction of Helix (R)

No. of Teeth (20)

Module (1)

Type (Ground Helical Gear)

Material (SCM440)

Material Type
S S45C H Helical Gears
K SCM440 HG Ground Helical Gear

129
 Helical Gears

Meets all high-speed rotation needs of industrial machines !

Characteristics Selection Hints

KHK stock helical gears are quiet, compact and economical. They It is important to thoroughly understand the contents of the product
are suitable wherever you require high-speed rotation including in tables as well as “CAUTION” notes before making the selection.
machine tools, speed reducers and other industrial machinery. You must specify the right or left hand by including the letter R or
L in the catalog number when ordering.

■ KHG Ground Helical Gears

① Have excellent strength and wear resistance which allow your
designs to be more compact. 1. Caution in Selecting the Mating Gears.
② Secondary operations are possible permitting modifications to Right hand and left hand helical gears mate as a set. See
suit your design. the photograph for reference. The table shows the possible
③ Use of a transverse module allows interchangeability with
combinations.
straight spur gears of the same module and numbers of teeth
at the same center distance. This feature is very convenient ■ Mating Helical Gear Selection Chart ( ○ Allowable × Not allowable)
when switching from spur gears to helical gears due to the gear
strength or the noise considerations. Catalog No. & KHG SH KRHG(F) SRH
④ The use of CBN grinding wheels produces consistent precision Helix Hand RH LH RH LH RH LH RH LH
with shorter grinding time, making these products easily
RH × ○ × × × ○ × ×
affordable. KHG
LH ○ × × × ○ × × ×
RH × × × ○ × × × ○
SH
LH × × ○ × × × ○ ×

(L) Left

■ SH Helical Gears
(R) Right
① SH helical gears fit a wide range of applications which have
made them popular choices for many years.
② Since helical gears have larger contact ratios than the equivalent
SS spur gears, they are effective in reducing noise and vibration.

Pinion (L) & Rack (R)

Pinion (R) & Rack (L)

130
 KHK Technical Information

2. Caution in Selecting Gears Based on Gear Strength 3. Caution with Regard to the Special Characteristics of Helical Gears
Allowable bending strength and surface durability values shown ① KHG ground helical gears and SH helical gears are not
in product tables were computed by assuming a certain application interchangeable due to different module systems, pressure angle
environment. They should be used as reference only. We designations and helix angles. The illustration below shows the
recommend that each user computes his own values by applying difference between the transverse module of KHG type and the
the actual usage conditions. normal module of SH type gears.

■ Calculation of Bending Strength of Gears

Catalog No. KHG SH
Item

Formula NOTE 1 Formula of spur and helical gears on bending strength (JGMA401-01)

No. of teeth of mating gears Same number of teeth Normal module

Transverse module

Rotation 600min-1 100min-1

CAUTION: Above is for illustration purpose only and not a
Durability Over 107 cycles representation of the true tooth forms.
Impact from motor Uniform load
Impact from load Uniform load
② Since SH helical gears use the normal module, the pitch circle
Direction of load Bidirectional
diameters and the center distance are not integral numbers.
Allowable bending stress at root σFlim NOTE 2 20kgf/mm2 12.67kgf/mm2 Please refer to the Table of SH Helical Gear Center Distance on
Safety factor SF 1.2 the product pages.

■ Calculation of Surface Durability (Except where it is common with bending strength)

4. Other Points to Consider in Selection Process
Formula NOTE 1 Formula of spur and helical gears on bending strength (JGMA402-01)
① There are various footnotes to the product pages under the
headings of “CAUTION” and “NOTE”. Please consider them
Kinematic viscosity of lubricant 100cSt(50℃ )
carefully when selecting these products.
Gear support Symmetric support by bearings ② There may be slight differences in color or shape of products
Allowable Hertz stress σHlim 116kgf/mm2 49kgf/mm2 shown in the photograph from the actual products.
③ KHK reserves the right to make changes in specifications and
Safety factor SH 1.15
dimensions without notice.
NOTE 1: The formula for gear strength is based on JGMA Standard. The units ④ KHK is ready to produce and supply custom order products.
for the rotational speed (min-1) and the load (kgf/mm2) were matched When you require specific gears different from KHK Stock
to the units needed in the equation.
NOTE 2: Since the load is bidirectional, the allowable bending stress at root Gears please contact our distributor for quotation. Also, please
σFlim is set to 2/3 of the value. refer to page 16 “KHK Custom Order Products”.

Definition of bending strength Definition of surface durability

The allowable bending The surface durability of
strength of a gear is defined a gear is defined as the
as the allowable tangential allowable tangential force
force at the pitch circle at the pitch circle, which
based on the mutually per mits the force to be
allowable root stress of two transmitted safely without
meshing gears under load. incurring surface failure.
Example of the failure due Example of the defacement
to insufficient bending due to insufficient surface
strength. durability.

131
 Helical Gear

Application Hints
In order to use KHK stock gears safely, carefully read the
Application Hints before proceeding.
If there are questions or if you require clarifications, please contact
our technical department or your nearest distributor.

KHK CO., LTD. TECHNICAL DEPARTMENT

PHONE: 81-48-254-1744 FAX: 81-48-254-1765
E-mail export@khkgears.co.jp

1. Caution on Performing Secondary Operations ⑥ To avoid problems of reduced gear precision and other
Most KHK gears can be modified by the user. Please note the manufacturing difficulties, do not attempt to machine the gears
following points. to reduce face widths.
① If you are reboring, it is important to pay special attention to ⑦ KHG Ground Helical Gears are already stress relieved. But if
locating the center in order to avoid runout. you subject them to a heavy turning operation such as removing
② The reference datum for gear cutting is the bore. Therefore, the hubs, the residual stress may cause deformation.
use the bore for locating the center. If it is too difficult to do for ⑧ When heat-treating SH Helical Gears, it is possible to get
small bores, the alternative is to use one spot on the bore and the thermal stress cracks. It is best to subject them to penetrant
runout of the side surface.
inspection afterwards. If the tooth strength is not sufficient, it
③ If the rework requires using scroll chucks, we recommend the
can be increased approximately four times by heat-treating. On
use of new or rebored jaws for improved precision. If chucking
the other hand, the precision of the gear will drop about one
by the teeth, please apply the pressure carefully to avoid
crushing the teeth which will lead to noisy gears. grade.

Lathe Operations
Heat Treatment
1) Induction Heat treatment of S45C products should
conform with the reference data below.
●Heat treatment temperature - 800~900°C
●Tempering temperature - 200~250°C
●Hardness - 48~53HRC

2) In general, gears made from S45C have not been heat-

treated. The user can heat-treat as required, but some
deformation will be introduced. Ordinarily, a grinding
process is needed after heat-treatment. Otherwise, the
precision grade will drop about one grade.

3) SUS303 and SUS304 belong to austenite family and

cannot be hardened. To harden stainless, there are
martensitic series, such as SUS420J2.

4) The induction hardened depth is approximately 1mm.

However, the hardening process does not completely
reach the root of the gear tooth at the center portion of
the face width.

④ The maximum bore size is dictated by the requirement that the

strength of the hub must be higher than that of the gear teeth.
⑤ In order to avoid stress concentrations, leave radii on the
keyway corners.

132
 KHK Technical Information

2. Points of Caution in Assembling

① KHK stock helical gears are designed to give the proper
CAUTION:
backlash when assembled using the center distance given by the The center distance of
formula on the right (center distance tolerance of H7~H8). The SH series is given in a
separate table.
amount of backlash is given in the product table for each gear.
② Because of the helix of the gear teeth, helical gears in mesh
produce thrust forces in the axial directions. The axial thrust where
d1 ＋ d2 a = center distance
bearings must be able to resist these forces. The direction of a=
the thrust forces depend on the helix hand and the direction of 2 d1 = pitch diameter of pinion
d2 = pitch diameter of gear
rotation as shown below
③ Please refer to overall length tolerance for Helical Gears on page
30.

Direction of rotation and driven drive

thrust force L L L L

R drive R R driven R

Thrust bearing
R Rack thrust L Pinion thrust R Pinion thrust L Rack thrust

L Rack thrust
R pinion thrust
R Rack thrust
L Pinion thrust drive drive

3. Notes on Starting Operations ④ The followings are the gear lubrication methods in general use:
① Before operating, check the following: (a) Grease Lubrication
● Are the gears firmly mounted on the shafts? (b) Splash Lubrication (Oil Bath Method)
● Have you eliminated uneven tooth contact? (c) Forced Oil Circulation Lubrication
● Does the gear mesh have the proper amount of backlash? Check lubrication after start up. Sometimes, when the unit is
(Please avoid the condition of no backlash.) initially being operated, lubricating oil deteriorates rapidly.
● Is there sufficient lubrication? 4. Other Points to Consider in Applications
② If the gears are exposed, install a safety cover for protection.
① KHK products are individually packaged to avoid damage.
Never touch gears while they are in motion.
Depending on how they are handled, it is still possible to deform
③ If there is unusual noise or vibration at the start up or
or break them. It is important to exercise care in handling these
insufficient lubrication after the start up, please recheck the
parts.
gears and correctness of the assembly. Some of the methods for
② Check the products as they are being taken out of the boxes. If
achieving noise reduction are:
any of them are rusted, scratched or dented, please return to the
(a) High Precision
dealer where they were bought, for exchange.
(b) Fine Tooth Surface Finish
③ KHK cannot guarantee the precision of gears once the customer
(c) Accurate Tooth Contact
performs a secondary operation on them.

133
 KHG Ground Helical Gears Transverse
Module 1
Helical
Gears

K
H
G

RH S1 Shape LH

■ Module 1
Catalog Module No. of teeth Bore Hub dia. Pitch dia. Outside dia. Face width NOTE 1 Hub width Total length
Direction of Helix
No. m z AH7 B C D E F G
KHG1- 20R R
1 020 6 17 020 022 8 10 18
KHG1- 20L L
KHG1- 22R R
1 022 8 18 022 024 8 10 18
KHG1- 22L L
KHG1- 24R R
1 024 8 20 024 026 8 10 18
KHG1- 24L L
KHG1- 25R R
1 025 8 20 025 027 8 10 18
KHG1- 25L L
KHG1- 28R R 1 028 8 20 028 030 8 10 18
KHG1- 28L L
KHG1- 30R R
1 030 10 25 030 032 8 10 18
KHG1- 30L L
KHG1- 32R R 1 032 10 25 032 034 8 10 18
KHG1- 32L L
KHG1- 35R R 1 035 10 25 035 037 8 10 18
KHG1- 35L L
KHG1- 36R R 1 036 10 25 036 038 8 10 18
KHG1- 36L L
KHG1- 40R R
1 040 10 30 040 042 8 10 18
KHG1- 40L L
KHG1- 44R R 1 044 10 30 044 046 8 10 18
KHG1- 44L L
KHG1- 45R R 1 045 10 30 045 047 8 10 18
KHG1- 45L L
KHG1- 48R R 1 048 10 30 048 050 8 10 18
KHG1- 48L L
KHG1- 50R R
1 050 12 35 050 052 8 10 18
KHG1- 50L L
KHG1- 60R R
1 060 12 40 060 062 8 10 18
KHG1- 60L L
KHG1- 70R R 1 070 12 40 070 072 8 10 18
KHG1- 70L L
KHG1- 80R R 1 080 15 50 080 082 8 10 18
KHG1- 80L L
KHG1- 90R R 1 090 15 50 090 092 8 10 18
KHG1- 90L L
KHG1-100R R 1 100 15 50 100 102 8 10 18
KHG1-100L L
CAUTION: Right handed and left handed helical gears of the same module are designed to mesh as a pair, but they are not interchangeable with SH type helical gears.
NOTE 1: It is possible to perform secondary operations except on the gear teeth. We recommend that you avoid shortening the hub which will lead to the deformation of the
gears.

134
 Ground Helical Gears

Specifications

Precision grade JIS N6 grade (JIS B1702-1: 1998) Heat treatment Thermal refined, tooth surfaces
OLD JIS 2 grade (JIS B1702: 1976) induction hardened

Helical
Reference section

Gears
of gear Rotating plane Tooth hardness 50~55HRC

Gear teeth Standard full depth Surface treatment Black oxide except ground surfaces
Transverse pressure
angle 20° Tooth surface finish Ground
K
Helix angle 21°30’ Datum reference surface Bore H
for gear grinding G
Material SCM440 Secondary Operations Possible except tooth area

Allowable torque (N.m) NOTE 2 Allowable torque (kgf.m) Backlash (mm) Weight Catalog
Shape
Bending strength Surface durability Bending strength Surface durability NOTE 3 (kgf) No.

S1 007.785 004.978 （0.7939） （00.5076） 0.08 ~ 0.16 0.03 KHG1- 20R

KHG1- 20L
S1 08.92 006.139 （0.9096） （00.6260） 0.08 ~ 0.16 0.04 KHG1- 22R
KHG1- 22L
S1 10.07 007.429 （1.0270） （00.7576） 0.08 ~ 0.16 0.05 KHG1- 24R
KHG1- 24L
S1 10.66 008.123 （1.0870） （00.8283） 0.08 ~ 0.16 0.05 KHG1- 25R
KHG1- 25L
S1 12.42 010.390 （1.2670） （01.0600） 0.08 ~ 0.16 0.06 KHG1- 28R
KHG1- 28L
S1 13.62 012.080 （1.3890） （01.2320） 0.08 ~ 0.16 0.07 KHG1- 30R
KHG1- 30L
S1 13.47 012.630 （1.3740） （01.2880） 0.08 ~ 0.16 0.08 KHG1- 32R
KHG1- 32L
S1 15.13 015.360 （1.5430） （01.5660） 0.08 ~ 0.16 0.09 KHG1- 35R
KHG1- 35L
S1 15.68 016.340 （1.5990） （01.6660） 0.08 ~ 0.16 0.09 KHG1- 36R
KHG1- 36L
S1 17.93 020.540 （1.8280） （02.0950） 0.08 ~ 0.16 0.12 KHG1- 40R
KHG1- 40L
S1 20.18 025.260 （2.0580） （02.5760） 0.08 ~ 0.16 0.14 KHG1- 44R
KHG1- 44L
S1 20.74 026.530 （2.1150） （02.7050） 0.08 ~ 0.16 0.14 KHG1- 45R
KHG1- 45L
S1 22.46 030.510 （2.2900） （03.1110） 0.08 ~ 0.16 0.16 KHG1- 48R
KHG1- 48L
S1 23.59 033.320 （2.4060） （03.3980） 0.08 ~ 0.16 0.18 KHG1- 50R
KHG1- 50L
S1 29.34 049.400 （2.9920） （05.0370） 0.10 ~ 0.18 0.26 KHG1- 60R
KHG1- 60L
S1 35.15 068.850 （3.5840） （07.0210） 0.10 ~ 0.18 0.32 KHG1- 70R
KHG1- 70L
S1 40.99 091.780 （4.1800） （09.3590） 0.10 ~ 0.18 0.44 KHG1- 80R
KHG1- 80L
S1 46.86 118.300 （4.7780） （012.060） 0.10 ~ 0.18 0.53 KHG1- 90R
KHG1- 90L
S1 50.44 141.900 （5.1440） （14.4700） 0.10 ~ 0.18 0.62 KHG1-100R
KHG1-100L
NOTE 2: The allowable torques shown in the table are the calculated values according to the assumed usage conditions.
Please see page 131 for more details.
NOTE 3: The backlash values shown in the table are the theoretical values of a pair of identical gears in mesh.

135
 KHG Ground Helical Gears Transverse
Module 1.5
Helical
Gears

K
H
G

RH S1 Shape LH

■ Module 1.5

Catalog Module No. of teeth Bore Hub dia. Pitch dia. Outside dia. Face width NOTE 1 Hub width Total length
Direction of Helix
No. m z AH7 B C D E F G
KHG1.5- 20R R
1.5 020 12 24 030.0 .033.0 12 12 24
KHG1.5- 20L L
KHG1.5- 22R R
1.5 022 12 26 033.0 .036.0 12 12 24
KHG1.5- 22L L
KHG1.5- 24R R
1.5 024 12 28 036.0 .039.0 12 12 24
KHG1.5- 24L L
KHG1.5- 25R R
1.5 025 12 30 037.5 .040.5 12 12 24
KHG1.5- 25L L
KHG1.5- 26R R 1.5 026 12 32 039.0 .042.0 12 12 24
KHG1.5- 26L L
KHG1.5- 28R R 1.5 028 15 36 042.0 .045.0 12 12 24
KHG1.5- 28L L
KHG1.5- 30R R
1.5 030 15 38 045.0 .048.0 12 12 24
KHG1.5- 30L L
KHG1.5- 32R R 1.5 032 15 40 048.0 .051.0 12 12 24
KHG1.5- 32L L
KHG1.5- 35R R
1.5 035 15 42 52.5 .055.5.0 12 12 24
KHG1.5- 35L L
KHG1.5- 36R R
1.5 036 15 45 .054.0 .057 .0 12 12 24
KHG1.5- 36L L
KHG1.5- 40R R 1.5 040 15 50 060.0 .063.0 12 12 24
KHG1.5- 40L L
KHG1.5- 44R R
1.5 044 15 50 066.0 .069.0 12 12 24
KHG1.5- 44L L
KHG1.5- 45R R
1.5 045 18 50 067.5 .070.5 12 12 24
KHG1.5- 45L L
KHG1.5- 48R R 1.5 048 18 50 072.0 .075.0 12 12 24
KHG1.5- 48L L
KHG1.5- 50R R 1.5 050 18 60 075.0 .078.0 12 12 24
KHG1.5- 50L L
KHG1.5- 52R R 1.5 052 18 60 078.0 081.0 12 12 24
KHG1.5- 52L L
KHG1.5- 60R R
1.5 060 20 60 090.0 093.0 12 12 24
KHG1.5- 60L L
KHG1.5- 70R R
1.5 070 20 60 105.0 108.0 12 12 24
KHG1.5- 70L L
KHG1.5- 80R R 1.5 080 20 70 120.0 123.0 12 12 24
KHG1.5- 80L L
KHG1.5- 90R R 1.5 090 20 70 135.0 138.0 12 12 24
KHG1.5- 90L L
KHG1.5-100R R 1.5 100 20 70 150.0 1530 12 12 24
KHG1.5-100L L
CAUTION: Right handed and left handed helical gears in the same module are designed to mesh as a pair, but they are not interchangeable with SH type helical gears.
NOTE 1: It is possible to perform secondary operations except on the gear teeth. We recommend that you avoid shortening the hub which will lead to the deformation of the
gears.

136
 Ground Helical Gears

Specifications

Precision grade JIS N6 grade (JIS B1702-1: 1998) Heat treatment Thermal refined, tooth surfaces
OLD JIS 2 grade (JIS B1702: 1976) induction hardened

Helical
Reference section

Gears
of gear Rotating plane Tooth hardness 50~55HRC

Gear teeth Standard full depth Surface treatment Black oxide except ground surfaces
Transverse pressure
angle 20° Tooth surface finish Ground
K
Helix angle 21°30’ Datum reference surface Bore H
for gear grinding G
Material SCM440 Secondary Operations Possible except tooth area

Allowable torque (N.m) NOTE 2 Allowable torque (kgf.m) Backlash (mm) Weight Catalog
Shape
Bending strength Surface durability Bending strength Surface durability NOTE 3 (kgf) No.

S1 026.27 018.53 （02.679） （01.890） 0.08 ~ 0.16 0.09 KHG1.5- 20R

KHG1.5- 20L
S1 027.37 （02.791） （02.124） 0.08 ~ 0.16 0.11 KHG1.5- 22R
020.83 KHG1.5- 22L
S1 030.90 025.30 （03.151） （02.580） 0.08 ~ 0.16 0.13 KHG1.5- 24R
KHG1.5- 24L
S1 032.70 027.71 （03.334） （02.826） 0.08 ~ 0.16 0.15 KHG1.5- 25R
KHG1.5- 25L
S1 034.49 030.24 （03.517） （03.084） 0.08 ~ 0.16 0.17 KHG1.5- 26R
KHG1.5- 26L
S1 038.120 035.67 （03.887） （03.637） 0.08 ~ 0.16 0.19 KHG1.5- 28R
KHG1.5- 28L
S1 041.78 041.57 （04.260） （04.239） 0.08 ~ 0.16 0.22 KHG1.5- 30R
KHG1.5- 30L
S1 045.47 047.96 （04.637） （04.891） 0.08 ~ 0.16 0.26 KHG1.5- 32R
KHG1.5- 32L
S1 051.06 058.47 （05.207） （05.962） 0.10 ~ 0.18 0.30 KHG1.5- 35R
KHG1.5- 35L
S1 052.94 062.22 （05.398） （06.345） 0.10 ~ 0.18 0.33 KHG1.5- 36R
KHG1.5- 36L
S1 060.49 078.49 （06.168） （08.004） 0.10 ~ 0.18 0.42 KHG1.5- 40R
KHG1.5- 40L
S1 068.11 096.79 （06.945） （09.870） 0.10 ~ 0.18 0.47 KHG1.5- 44R
KHG1.5- 44L
S1 070.02 101.70 （07.140） （10.370） 0.10 ~ 0.18 0.47 KHG1.5- 45R
KHG1.5- 45L
S1 075.78 117.20 （07.727） （11.950） 0.10 ~ 0.18 0.52 KHG1.5- 48R
KHG1.5- 48L
S1 079.63 128.20 （08.120） （13.070） 0.10 ~ 0.18 0.63 KHG1.5- 50R
KHG1.5- 50L
S1 083.49 139.60 （08.514） （14.240） 0.10 ~ 0.18 0.67 KHG1.5- 52R
KHG1.5- 52L
S1 099.05 191.00 （10.100） （19.480） 0.10 ~ 0.18 0.81 KHG1.5- 60R
KHG1.5- 60L
S1 113.50 256.00 （11.570） （26.100） 0.12 ~ 0.20 1.00 KHG1.5- 70R
KHG1.5- 70L
S1 132.30 342.70 （13.490） （34.950） 0.12 ~ 0.20 1.40 KHG1.5- 80R
KHG1.5- 80L
S1 151.20 442.30 （15.420） （45.100） 0.12 ~ 0.20 1.65 KHG1.5- 90R
KHG1.5- 90L
S1 170.20 554.40 （17.360） （56.530） 0.12 ~ 0.20 1.97 KHG1.5-100R
KHG1.5-100L
NOTE 2: The allowable torques shown in the table are the calculated values according to the assumed usage conditions.
Please see page 131 for more details.
NOTE 3: The backlash values shown in the table are the theoretical values of a pair of identical gears in mesh.

137
 KHG Ground Helical Gears Transverse
Module 2
Helical
Gears

K
H
G

RH S1 Shape LH
■ Module 2
Catalog Module No. of teeth Bore Hub dia. Pitch dia. Outside dia. Face width NOTE 1 Hub width Total length
Direction of Helix
No. m z AH7 B C D E F G
KHG2- 15R R
2 015 12 024 030 034 16 13 29
KHG2- 15L L
KHG2- 16R R
2 016 12 026 032 036 16 13 29
KHG2- 16L L
KHG2- 18R R
2 018 12 030 036 040 16 13 29
KHG2- 18L L
KHG2- 20R R
2 020 15 032 040 044 16 13 29
KHG2- 20L L
KHG2- 22R R
2 022 15 036 044 048 16 13 29
KHG2- 22L L
KHG2- 24R R
2 024 15 038 048 052 16 13 29
KHG2- 24L L
KHG2- 25R R
2 025 15 040 050 054 16 13 29
KHG2- 25L L
KHG2- 26R R
2 026 15 042 052 056 16 13 29
KHG2- 26L L
KHG2- 28R R
2 028 15 045 056 060 16 13 29
KHG2- 28L L
KHG2- 30R R
2 030 18 050 060 064 16 13 29
KHG2- 30L L
KHG2- 32R R
2 032 18 050 064 068 16 13 29
KHG2- 32L L
KHG2- 35R R
2 035 18 050 070 074 16 13 29
KHG2- 35L L
KHG2- 36R R
2 036 18 050 072 076 16 13 29
KHG2- 36L L
KHG2- 40R R
2 040 20 060 080 084 16 13 29
KHG2- 40L L
KHG2- 44R R
2 044 20 060 088 092 16 13 29
KHG2- 44L L
KHG2- 45R R
2 045 20 060 090 094 16 13 29
KHG2- 45L L
KHG2- 48R R
2 048 20 060 096 100 16 13 29
KHG2- 48L L
KHG2- 50R R
2 050 25 060 100 104 16 13 29
KHG2- 50L L
KHG2- 52R R
2 052 25 065 104 108 16 13 29
KHG2- 52L L
KHG2- 60R R
2 060 25 065 120 124 16 13 29
KHG2- 60L L
KHG2- 70R R
2 070 25 070 140 144 16 13 29
KHG2- 70L L
KHG2- 80R R
2 080 25 080 160 164 16 13 29
KHG2- 80L L
KHG2- 90R R
2 090 25 090 180 184 16 13 29
KHG2- 90L L
KHG2-100R R
2 100 25 100 200 204 16 13 29
KHG2-100L L
CAUTION: Right handed and left handed helical gears in the same module are designed to mesh as a pair, but they are not interchangeable with SH type helical gears.
NOTE 1: It is possible to perform secondary operations except on the gear teeth. We recommend that you avoid shortening the hub which will lead to the deformation of the
gears.
138
 Ground Helical Gears

Specifications

Precision grade JIS N6 grade (JIS B1702-1: 1998) Heat treatment Thermal refined, tooth surfaces
OLD JIS 2 grade (JIS B1702: 1976) induction hardened

Helical
Reference section

Gears
of gear Rotating plane Tooth hardness 50~55HRC

Gear teeth Standard full depth Surface treatment Black oxide except ground surfaces
Transverse pressure
angle 20° Tooth surface finish Ground
K
Helix angle 21°30’ Datum reference surface Bore H
for gear grinding G
Material SCM440 Secondary Operations Possible except tooth area

Allowable torque (N.m) NOTE 2 Allowable torque (kgf.m) Backlash (mm) Weight Catalog
Shape
Bending strength Surface durability Bending strength Surface durability NOTE 3 (kgf) No.
KHG2- 15R
S1 040.45 0022.75 （04.125） （002.320） 0.10 ~ 0.20 0.11
KHG2- 15L
0.13 KHG2- 16R
S1 040.63 0024.09 （04.143） （002.457） 0.10 ~ 0.20 KHG2- 16L
KHG2- 18R
S1 048.53 0031.86 （04.949） （003.249） 0.10 ~ 0.20 0.17 KHG2- 18L
KHG2- 20R
S1 056.62 0040.83 （05.774） （004.164） 0.10 ~ 0.20 0.20 KHG2- 20L
KHG2- 22R
S1 064.87 0050.56 （06.615） （005.156） 0.10 ~ 0.20 0.25 KHG2- 22L
KHG2- 24R
S1 073.25 0061.43 （07.470） （006.264） 0.10 ~ 0.20 0.30 KHG2- 24L
KHG2- 25R
S1 077.49 0067.29 （07.902） （006.862） 0.10 ~ 0.20 0.33 KHG2- 25L
KHG2- 26R
S1 081.76 0073.44 （08.337） （007.489） 0.12 ~ 0.22 0.37 KHG2- 26L
KHG2- 28R
S1 090.35 0086.62 （09.213） （008.833） 0.12 ~ 0.22 0.43 KHG2- 28L
KHG2- 30R
S1 099.05 0101.00 （10.100） （010.300） 0.12 ~ 0.22 0.50 KHG2- 30L
KHG2- 32R
S1 107.80 0116.50 （10.990） （011.880） 0.12 ~ 0.22 0.55 KHG2- 32L
KHG2- 35R
S1 121.00 0142.20 （12.340） （014.500） 0.12 ~ 0.22 0.63 KHG2- 35L
（12.800） （015.430） 0.12 ~ 0.22 KHG2- 36R
S1 125.50 151.3 0.65 KHG2- 36L
KHG2- 40R
S1 143.40 0191.00 （14.620） （019.480） 0.12 ~ 0.22 0.85 KHG2- 40L
KHG2- 44R
S1 161.40 0235.70 （16.460） （024.040） 0.12 ~ 0.22 0.98 KHG2- 44L
KHG2- 45R
S1 165.90 0247.70 （16.920） （025.260） 0.12 ~ 0.22 1.00 KHG2- 45L
KHG2- 48R
S1 171.80 0273.20 （17.520） （027.860） 0.12 ~ 0.22 1.10 KHG2- 48L
KHG2- 50R
S1 180.50 0298.90 （18.410） （030.480） 0.12 ~ 0.22 1.20 KHG2- 50L
KHG2- 52R
S1 189.30 0326.00 （19.300） （033.240） 0.14 ~ 0.24 1.29 KHG2- 52L
KHG2- 60R
S1 224.60 0446.70 （22.900） （045.550） 0.14 ~ 0.24 1.60 KHG2- 60L
KHG2- 70R
S1 269.00 0624.80 （27.430） （063.710） 0.14 ~ 0.24 2.20 KHG2- 70L
（30.650） （081.440） 0.14 ~ 0.24 KHG2- 80R
S1 300.60 798.6 2.90 KHG2- 80L
KHG2- 90R
S1 343.60 1030.00 （35.040） （105.000） 0.14 ~ 0.24 3.37 KHG2- 90L
KHG2-100R
S1 386.70 1290.00 （39.430） （131.500） 0.14 ~ 0.24 4.63
KHG2-100L
NOTE 2: The allowable torques shown in the table are the calculated values according to the assumed usage conditions. Please see page 131 for more details.
NOTE 3: The backlash values shown in the table are the theoretical values of a pair of identical gears in mesh.

139
 KHG Ground Helical Gears Transverse
Module 2.5
Helical
Gears

K
H
G

RH S1 Shape LH

■ Module 2.5

Catalog Module No. of teeth Bore Hub dia. Pitch dia. Outside dia. Face width NOTE 1 Hub width Total length
Direction of Helix
No. m z AH7 B C D E F G
KHG2.5-15R R
2.5 15 15 30 037.5 042.5 20 14 34
KHG2.5-15L L
KHG2.5-16R R
2.5 16 15 32 040.0 045.0 20 14 34
KHG2.5-16L L
KHG2.5-18R R 2.5 18 15 38 045.0 050.0 20 14 34
KHG2.5-18L L
KHG2.5-20R R 2.5 20 18 40 050.0 055.0 20 14 34
KHG2.5-20L L
KHG2.5-22R R 2.5 22 18 44 055.0 060.0 20 14 34
KHG2.5-22L L
KHG2.5-24R R
2.5 24 18 48 060.0 065.0 20 14 34
KHG2.5-24L L
KHG2.5-25R R 2.5 25 20 50 062.5 067.5 20 14 34
KHG2.5-25L L
KHG2.5-26R R
2.5 26 20 50 065.0 070.0 20 14 34
KHG2.5-26L L
KHG2.5-28R R 2.5 28 20 60 070.0 075.0 20 14 34
KHG2.5-28L L
KHG2.5-30R R
2.5 30 20 65 075.0 080.0 20 14 34
KHG2.5-30L L
KHG2.5-32R R 2.5 32 20 70 080.0 085.0 20 14 34
KHG2.5-32L L
KHG2.5-35R R 2.5 35 20 70 087.5 0092.5.0 20 14 34
KHG2.5-35L L
KHG2.5-36R R 2.5 36 20 70 090.0 095.0 20 14 34
KHG2.5-36L L
KHG2.5-40R R
2.5 40 25 70 100.0 105.0 20 14 34
KHG2.5-40L L
KHG2.5-44R R 2.5 44 25 75 110.0 115.0 20 14 34
KHG2.5-44L L
KHG2.5-45R R 2.5 45 25 75 112.5 117.5 20 14 34
KHG2.5-45L L
KHG2.5-48R R
2.5 48 25 75 1200 125.0 20 14 34
KHG2.5-48L L
KHG2.5-50R R 2.5 50 25 80 1250 130.0 20 14 34
KHG2.5-50L L
KHG2.5-52R R 2.5 52 25 80 1300 135.0 20 14 34
KHG2.5-52L L
KHG2.5-60R R
2.5 60 25 80 1500 155.0 20 14 34
KHG2.5-60L L
CAUTION: Right handed and left handed helical gears in the same module are designed to mesh as a pair, but they are not interchangeable with SH type helical gears.
NOTE 1: It is possible to perform secondary operations except on the gear teeth. We recommend that you avoid shortening the hub which will lead to the deformation of the
gears.

140
 Ground Helical Gears

Specifications

Precision grade JIS N6 grade (JIS B1702-1: 1998) Heat treatment Thermal refined, tooth surfaces
OLD JIS 2 grade (JIS B1702: 1976) induction hardened

Helical
Reference section

Gears
of gear Rotating plane Tooth hardness 50~55HRC

Gear teeth Standard full depth Surface treatment Black oxide except ground surfaces
Transverse pressure
angle 20° Tooth surface finish Ground
K
Helix angle 21°30’ Datum reference surface Bore H
for gear grinding G
Material SCM440 Secondary Operations Possible except tooth area

Allowable torque (N.m) NOTE 2 Allowable torque (kgf.m) Backlash (mm) Weight Catalog
Shape
Bending strength Surface durability Bending strength Surface durability NOTE 3 (kgf) No.

S1 071.82 0.10 ~ 0.20 0.21 KHG2.5-15R

041.09 （07.324） （04.190）
KHG2.5-15L
S1 079.36 0.10 ~ 0.20 0.25 KHG2.5-16R
047.93 （08.093） （04.888）
KHG2.5-16L
S1 094.78 063.40 （09.665） （06.465） 0.10 ~ 0.20 0.34 KHG2.5-18R
KHG2.5-18L
S1 110.60 081.25 （11.280） （08.285） 0.10 ~ 0.20 0.39 KHG2.5-20R
KHG2.5-20L
S1 126.70 100.60 （12.920） （10.260） 0.12 ~ 0.22 0.49 KHG2.5-22R
KHG2.5-22L
S1 143.10 122.30 （14.590） （12.470） 0.12 ~ 0.22 0.60 KHG2.5-24R
KHG2.5-24L
S1 151.30 134.00 （15.430） （13.660） 0.12 ~ 0.22 0.64 KHG2.5-25R
KHG2.5-25L
S1 159.70 146.20 （16.280） （14.910） 0.12 ~ 0.22 0.65 KHG2.5-26R
KHG2.5-26L
S1 176.40 172.60 （17.990） （17.600） 0.12 ~ 0.22 0.87 KHG2.5-28R
KHG2.5-28L
S1 193.40 201.20 （19.720） （20.520） 0.12 ~ 0.22 1.00 KHG2.5-30R
KHG2.5-30L
S1 210.50 232.30 （21.470） （23.690） 0.12 ~ 0.22 1.20 KHG2.5-32R
KHG2.5-32L
S1 236.40 283.60 （24.110） （28.920） 0.12 ~ 0.22 1.30 KHG2.5-35R
KHG2.5-35L
S1 245.10 301.90 （24.990） （30.790） 0.12 ~ 0.22 1.40 KHG2.5-36R
KHG2.5-36L
S1 267.80 364.90 （27.310） （37.210） 0.12 ~ 0.22 1.60 KHG2.5-40R
KHG2.5-40L
S1 301.60 450.80 （30.750） （45.970） 0.14 ~ 0.24 1.90 KHG2.5-44R
KHG2.5-44L
S1 310.10 473.90 （31.620） （48.320） 0.14 ~ 0.24 2.00 KHG2.5-45R
KHG2.5-45L
S1 335.60 546.70 （34.220） （55.750） 0.14 ~ 0.24 2.20 KHG2.5-48R
KHG2.5-48L
S1 352.60 598.50 （35.960） （61.030） 0.14 ~ 0.24 2.40 KHG2.5-50R
KHG2.5-50L
S1 369.70 652.30 （37.700） （66.520） 0.14 ~ 0.24 2.50 KHG2.5-52R
KHG2.5-52L
S1 438.50 890.10 （44.720） （90.770） 0.14 ~ 0.24 3.30 KHG2.5-60R
KHG2.5-60L
NOTE 2: The allowable torques shown in the table are the calculated values according to the assumed usage conditions.
Please see page 131 for more details.
NOTE 3: The backlash values shown in the table are the theoretical values of a pair of identical gears in mesh.

141
 KHG Ground Helical Gears Transverse
Module 3
Helical
Gears

K
H
G

RH S1 Shape LH

■ Module 3

Catalog Module No. of teeth Bore Hub dia. Pitch dia. Outside dia. Face width NOTE 1 Hub width Total length
Direction of Helix
No. m z AH7 B C D E F G
KHG3-15R R 3 15 18 36 045 051 25 16 41
KHG3-15L L
KHG3-16R R
3 16 18 38 048 054 25 16 41
KHG3-16L L
KHG3-18R R
3 18 18 40 054 060 25 16 41
KHG3-18L L
KHG3-20R R
3 20 20 50 060 066 25 16 41
KHG3-20L L
KHG3-22R R 3 22 20 54 066 072 25 16 41
KHG3-22L L
KHG3-24R R
3 24 20 58 072 078 25 16 41
KHG3-24L L
KHG3-25R R 3 25 20 60 075 081 25 16 41
KHG3-25L L
KHG3-26R R 3 26 20 60 078 084 25 16 41
KHG3-26L L
KHG3-28R R 3 28 20 70 084 090 25 16 41
KHG3-28L L
KHG3-30R R
3 30 25 75 090 096 25 16 41
KHG3-30L L
KHG3-32R R 3 32 25 75 096 102 25 16 41
KHG3-32L L
KHG3-35R R 3 35 25 80 105 111 25 16 41
KHG3-35L L
KHG3-36R R
3 36 25 80 108 114 25 16 41
KHG3-36L L
KHG3-40R R 3 40 25 80 120 126 25 16 41
KHG3-40L L
KHG3-44R R 3 44 25 80 132 138 25 16 41
KHG3-44L L
KHG3-45R R 3 45 25 80 135 141 25 16 41
KHG3-45L L
KHG3-48R R 3 48 25 85 144 150 25 16 41
KHG3-48L L
KHG3-50R R 3 50 30 85 150 156 25 16 41
KHG3-50L L
KHG3-52R R 3 52 30 85 156 162 25 16 41
KHG3-52L L
KHG3-60R R
3 60 30 90 180 186 25 16 41
KHG3-60L L
CAUTION: Right handed and left handed helical gears in the same module are designed to mesh as a pair, but they are not interchangeable with SH type helical gears.
NOTE 1: It is possible to perform secondary operations except on the gear teeth. We recommend that you avoid shortening the hub which will lead to the deformation of the
gears.

142
 Ground Helical Gears

Specifications

Precision grade JIS N6 grade (JIS B1702-1: 1998) Heat treatment Thermal refined, tooth surfaces
OLD JIS 2 grade (JIS B1702: 1976) induction hardened

Helical
Reference section

Gears
of gear Rotating plane Tooth hardness 50~55HRC

Gear teeth Standard full depth Surface treatment Black oxide except ground surfaces
Transverse pressure
angle 20° Tooth surface finish Ground
K
Helix angle 21°30’ Datum reference surface Bore H
for gear grinding G
Material SCM440 Secondary Operations Possible except tooth area

Allowable torque (N.m) NOTE 2 Allowable torque (kgf.m) Backlash (mm) Weight Catalog
Shape
Bending strength Surface durability Bending strength Surface durability NOTE 3 (kgf) No.

S1 129.3 74.69 （13.18） （007.616） 0.10 ~ 0.20 0.36 KHG3-15R

KHG3-15L
S1 142.9 87.16 （14.57） （008.888） 0.10 ~ 0.20 0.42 KHG3-16R
KHG3-16L
KHG3-18R
S1 170.6 115.3 （17.40） （011.760） 0.12 ~ 0.22 0.53
KHG3-18L
KHG3-20R
S1 199.1 148.0 （20.30） （015.090） 0.12 ~ 0.22 0.70
KHG3-20L
S1 228.1 184.1 （23.26） （018.770） 0.12 ~ 0.22 0.86 KHG3-22R
KHG3-22L
S1 257.5 223.8 （26.26） （022.820） 0.12 ~ 0.22 1.00 KHG3-24R
KHG3-24L
S1 272.4 245.2 （27.78） （025.000） 0.12 ~ 0.22 1.10 KHG3-25R
KHG3-25L
S1 287.4 267.7 （29.31） （027.300） 0.12 ~ 0.22 1.20 KHG3-26R
KHG3-26L
S1 317.6 316.1 （32.39） （032.230） 0.12 ~ 0.22 1.50 KHG3-28R
KHG3-28L
S1 348.1 368.7 （35.50） （037.600） 0.12 ~ 0.22 1.60 KHG3-30R
KHG3-30L
S1 362.5 407.4 （36.96） （041.540） 0.12 ~ 0.22 1.80 KHG3-32R
KHG3-32L
S1 407.0 497.6 （41.50） （050.740） 0.14 ~ 0.26 2.20 KHG3-35R
KHG3-35L
S1 422.0 529.8 （43.03） （054.030） 0.14 ~ 0.26 2.30 KHG3-36R
KHG3-36L
S1 482.1 670.1 （49.16） （068.330） 0.14 ~ 0.26 2.70 KHG3-40R
KHG3-40L
S1 542.9 827.5 （55.36） （084.380） 0.14 ~ 0.26 3.20 KHG3-44R
KHG3-44L
S1 558.1 869.2 （56.91） （088.630） 0.14 ~ 0.26 3.30 KHG3-45R
KHG3-45L
S1 604.0 1000.00 （61.59） （102.000） 0.14 ~ 0.26 3.80 KHG3-48R
KHG3-48L
S1 634.8 1094.00 （64.73） （111.600） 0.14 ~ 0.26 4.00 KHG3-50R
KHG3-50L
S1 665.6 1191.00 （67.87） （121.500） 0.14 ~ 0.26 4.20 KHG3-52R
KHG3-52L
S1 756.6 1560.00 （77.15） （159.100） 0.14 ~ 0.26 5.60 KHG3-60R
KHG3-60L
NOTE 2: The allowable torques shown in the table are the calculated values according to the assumed usage conditions.
Please see page 131 for more details.
NOTE 3: The backlash values shown in the table are the theoretical values of a pair of identical gears in mesh.

143
 SH Helical Gears Normal
Modules 2~3
Helical
Gears

S
H

RH S1 Shape LH

■ Module 2

Catalog Module No. of teeth Bore Hub dia. Pitch dia. Outside dia. Face width Hub width Total length
Direction of Helix
No. m z AH7 B C D E F G
SH2-15R R
2 15 12 024 031.06 035.06 25 10 35
SH2-15L L
SH2-20R R
2 20 12 032 041.41 045.41 25 10 35
SH2-20L L
SH2-30R R
2 30 12 050 062.12 066.12 25 10 35
SH2-30L L
SH2-40R R
2 40 18 060 082.82 086.82 25 10 35
SH2-40L L
SH2-60R R 2 60 18 070 124.23 128.23 25 10 35
SH2-60L L
SH2-90R R
2 90 18 120 186.35 190.35 25 10 35
SH2-90L L

■ Module 3
SH3-15R R 3 15 15 036 046.59 052.59 35 15 50
SH3-15L L
SH3-20R R 3 20 15 050 062.12 068.12 35 15 50
SH3-20L L
SH3-30R R 3 30 20 070 093.17 099.17 35 15 50
SH3-30L L
SH3-40R R 3 40 20 080 124.23 130.23 35 15 50
SH3-40L L
SH3-60R R
3 60 20 140 186.35 192.35 35 15 50
SH3-60L L
CAUTION: Right handed and left handed helical gears in the same module are designed to mesh as a pair, but they are not interchangeable with KHG type helical gears.

144
 Helical Gears

Specifications

Precision grade JIS N8 grade (JIS B1702-1: 1998) Heat treatment -

OLD JIS 4 grade (JIS B1702: 1976)

Helical
Reference section

Gears
of gear Normal plane Tooth hardness Less than 194HB

Gear teeth Standard full depth Surface treatment Black oxide

Transverse pressure
angle 20° Tooth surface finish Cut
S
Helix angle 15° Datum reference surface Bore H
for gear cutting
Material S45C Secondary Operations Possible

Allowable torque (N.m) NOTE 1 Allowable torque (kgf.m) Backlash (mm) Weight Catalog
Shape
Bending strength Surface durability Bending strength Surface durability NOTE 2 (kgf) No.

S1 43.72 002.895 （04.458） （00.2952） 0.12 ~ 0.26 0.16 SH2-15R

SH2-15L
S1 0 67.11 005.851 （06.843） （00.5966） 0.12 ~ 0.26 0.31 SH2-20R
SH2-20L
S1 116.8 015.250 （11.910） （01.5550） 0.14 ~ 0.30 0.70 SH2-30R
SH2-30L
S1 168.6 028.920 （17.190） （02.9490） 0.14 ~ 0.30 1.20 SH2-40R
SH2-40L
S1 274.9 070.810 （28.030） （07.2210） 0.18 ~ 0.360 3.00 SH2-60R
SH2-60L
S1 437.4 173.000 （44.600） （17.6400） 0.18 ~ 0.360 6.10 SH2-90R
SH2-90L

S1 137.7 009.672 （14.04） （00.9863） 0.16 ~ 0.32 0.5 SH3-15R

SH3-15L
S1 211.3 019.390 （21.55） （01.9770） 0.16 ~ 0.32 1.0 SH3-20R
SH3-20L
S1 367.8 050.200 （37.51） （05.1190） 0.18 ~ 0.38 2.2 SH3-30R
SH3-30L
S1 530.8 095.460 （54.13） （09.7340） 0.18 ~ 0.38 3.8 SH3-40R
SH3-40L
S1 865.8 235.500 （88.29） （24.0100） 0.22 ~ 0.44 9.3 SH3-60R
SH3-60L
NOTE 1: The allowable torques shown in the table are calculated values according to the assumed usage conditions.
Please see page 131 for more details.
NOTE 2: The backlash values shown in the table are the theoretical values of a pair of identical gears in mesh.

■ SH Helical Gear Center Distance ■ SH Helical Gear Center Distance

R R R R R R
Catalog No. SH2-15 L SH2-20 L SH2-30 L SH2-40 L SH2-60 L SH2-90 L Catalog No. SH3-15R
L SH3-20R
L SH3-30R
L SH3-40R
L SH3-60R
L

SH2-15 R
L 031.05 — — — — — R
SH3-15 L 046.58 — — — —

SH2-20 R 36.23 041.41 — — — — R

L SH3-20 L 054.34 062.11 — — —
SH2-30 R
L
046.58 051.76 062.11 — — —
R
SH3-30 L 069.87 077.64 093.17 — —
SH2-40 R
L
056.93 062.11 072.46 082.82 — —
SH3-40 R 085.40 093.17 108.70 124.23 —
SH2-60 R
L
077.64 082.82 093.17 103.52 124.23 — L

R
SH2-90 R
L 108.70 113.88 124.23 134.58 155.29 186.35 SH3-60 L 116.46 124.23 139.76 155.29 186.35

145