F series – Spur Gears and Locking Hub Assemblies

picture of Fseries

Features :
– Completed in 2 working days !
– 3 product lines, 2100 items standardized

What are spur gears and locking hub assemblies ?

  • They are KHK’s own products with standardized secondary operations
    Based on standard gears with pilot holes, KHK has created its own specification of bushing and gear combinations resulting in 3 products made up of 2100 items.
  • Pursuit of production efficiency and quality
    We pursue production efficiency and quality by using the latest equipment and JIT production line.
    We offer highly reliable products by performing secondary operations by ourselves.
  • Quick delivery to you
    Quick response from standard gears in stock to the JIT production line.
    You can purchase 1 to 20 pieces by catalog number, and the order is completed in two working days.
    (We will provide separate quotes for quantities 21 and above.)


(Note 1: The working days exclude our company holidays and the day the order is placed)
(Note 2: Since the production starts immediately after receipt of order, we cannot accept cancellations)


Trouble with movement between the gear and shaft !
Problem with run-out after secondary operation !
Solve all these worries !

picture of Fseries2


Please order by specifying
Catalog number + F + bore size + type
Example : When the catalog number is SS2-60 and bore size is 20mm => SS2-60F20A


Mounting directions for spur gear and locking hub assembly
Example / Two piece type

construction_of_F_seriesF series principal

Mounting Method and Notes of Caution

attention 1

  1. Recommended shaft diameter tolerance is  h7.  The limit is h8, but to reduce run-out we recommend h6. Also, surface finish of the shaft should be  1.6a.
  2. Carefully wipe off garbage, dirt and oil from the surfaces of the bushing and shaft and tighten only after the shaft is completely through the bushing. Also, in order to be able to disassemble, it is necessary to have 1mm or more of a gap on the back side of the gear.  (Figure 1).
  3. The method of tightening the screws is to tighten the screws on the diagonal opposite with  a torque wrench. First, tighten the screws to 1/4 of the specified torque, then tighten to 1/2 of the specified torque, and finally tighten to the specified torque. Do not tighten without a shaft or tighten the screw in the tapped hole for removal. (Figure 2).
  4. If there is a keyway on the shaft, the transmission power is reduced by 15 – 20% due to the reduced contact surface in the locking portion.


Disassembly Method and Notes of Caution

attention 2

  1. Shut the power source (electrical supply) and confirm there is no load on the gear and no danger of the gear falling.
  2. Place all the screws removed into the tapped hole for removal and slowly and evenly tighten in a diagonal sequence. The locking bushing will come off.
  3. If the tightening screw is reused, the damages on the seating and screw surfaces will reduce the locking force.  The use of new same size screws is recommended.


Pinions Designed for Speed Reducers

SSAG Ground Spur Gears
SSAG spur gear
(Can also be used as  general purpose gears)

This is in response to subjects and news from users such as below :

  • It takes time and effort in estimating, delivery adjustment, making drawings, calculating strength, etc.
  • It takes labor to order gears which matches the output flange of the speed reducers.


Specifications :

  • Precision grade / JIS N7 (JIS B 1702-1: 1998) / JIS grade 3 (JIS B 1702: 1976)
  • Gear teeth / Standard full depth
  • Pressure angle / 20 degrees
  • Material / S45C
  • Heat treatment / Tooth surface induction hardened
  • Tooth hardness / 50 – 60 HRC
  • Surface treatment / Black oxide finish except gear teeth
  • Gears in m1 – 6 in 66 configurations are standardized.


Laser Hardening

srf hl_machine

New SRF-HL Hardened Racks

  • Latest Heat Treating Technology !
  • Racks in m1.5 – 6 in 21 configurations are standardized (J Series is also available)
  • Utilizing laser for tooth surface hardening !
  • These heat treated racks achieved less distortion


Specifications :

  • Precision grade / KHK R 001 5
  • Gear teeth / Standard full depth
  • Pressure angle / 20 degrees
  • Material / S45C
  • Heat treatment / Laser hardened tooth surface
  • Tooth hardness / 55 – 65 HRC
  • Surface treatment / Black oxide finish