KHK Spur Gear Catalogue - KHK - (Version JPG) - Page n° 3 - PDF Catalogue | Technical Documentation

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Bevel gear, Planetary gearbox, Flexible coupling, Rack and pinion, Gear

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KHK Technical information

Selection Hints

Please select the most suitable products by carefully considering the characteristics of items and contents of the product tables. It is also important to read all applicable "CAUTION" notes before the final selection. Use of catalog numbers when ordering will simplify and expedite the processing of your order.

1. Caution in selecting the mating Gears

2. Caution in Selecting Gears Based on Gear Strength

the teeth can be mated.

© When using a pinion with an internal gear with a small difference in the numbers of teeth, there are possibilities for involute interference, trochoid interference and trimming interference. See the internal gear interference

portion of the technical section to avoid problems in

assembling these items. (Page 277) ■ Calculation of Bending Strength of Gears

The gear strength values shown in the product pages were computed by assuming a certain application environment. Therefore, they should be used as reference only. We recommend that each user computes his own values

by applying the actual usage conditions. Also, SUSL Fairloc hub spur gears, DSL Fairloc hub spur gears and SSAY/K spur gears with built-in clamps need additional considerations of the starting torque.

The table below contains the assumptions established for

various products in order to compute gear strengths.


Catalog No. Item	MSGA MSGB	SSGS	SSG	SSS,SS,SSA SSY,SSAY SSAY/K SSR	SUS SUSA SUSL LS	BSS	NSU	PU PS PSA	DSL DS
Formula note 1	Formula of spur and helical gears on bending strength(JGMA401-01)						The Lewis formula
No. of teeth of mating gears	Same number of teeth(30 for SSGS,SSS,SSR)						-
Rotation	600rpm			100rpm			100rpm
Durability	Over 10⁷ cycles						-
Impact from motor	Uniform load						Allowable Bending Stress (kgf/mm²)
Impact from load	Uniform load						1.59 (40Cwith No Lubrication)	1.15 SET	m 0.8 î0 m i0 3 5 Wwith Grease Lubrication)
Direction of load	Bidirectional
Allowable bending stresss at root o_mm (kgf/mm²) note i	47	24.5	19	19(24.5) Note3	10.5	4
Safety factor Sf	1.2
■ Calculation of Surface Durability (Except where it is common with Bending Strength)
Formula note i	Formula of spur and helical gears on surface durability(JGMA402-01)
Kinematic viscosity of lubricant	100cSt(50°C)
Gear support	Symmetric support by bearings Note 4
Allowable Hertz stress ohm (kgf/mm²)	166	99	90	49 (62.5) note 3	41.3	-
Safety factor Sh	1.15

[NOTE 1]JGMA (Japanese Manufacturers' Association),"MC Nylon Technical Data" of Nippon Polypenco Limited and "Duracon Gear" of Polyplastic Co. The units for

rotational speed (rpm) and the load (kgf/mm2) were matched to the units needed in the equation. [NOTE 2]Since the load is bidirectional, the allowable bending stress at root ofm, calculated from JGMA 401-01, is set to 2/3 of the value.

[NOTE 3]For SSS Spur Pinion Shafts, with module over 1.5, teeth induction hardening is not applied. Allowable bending stress and allowable hertz stress are referred to the value shown in the parentheses.

[NOTE 4]Spur Pinion Shafts (SSS) with module below 1.0 (SA configuration) are cantilever support as it is a single shaft type.

■ Definition of bending strength by jgma 401-01 (1974)

The allowable bending

strength of a gear is defined as

the allowable tangential force at the pitch circle based on the mutually aallowable root stress of two meshing gears under load.

^Example ^of ^the ^failure ^due ^to

insufficient bending strength.

■ Definition of surface durability by jgma 402-01 (1975)

The surface durability of a gear is defined as the allowable tangential force at the pitch circle, which permits the force to be transmitted safely

without incurring surface

failure.

Example of the defacement due to insufficient surface durability.

KHK Spur Gear Catalogue - KHK - #3

Bevel gear, Planetary gearbox, Flexible coupling, Rack and pinion, Gear