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GMN Bearing USA

RPM Shouldn’t be a Limiting Factor

Our high torque capacity FE 8000 sprag clutch is unlike any other clutch of its kind on the market today. Here is what sets it apart:

GMN FE 8000 Series- Why it's so great. No RPM Limits. More sprags per clutch than any competitor on the market. Unique sprag design allows the sprags to engage at any speed.
A. Our sprags have a unique design.
  • Sprags will engage at any speed, has no RPM limits.
  • Sprags have a constant clamping angle for increased reliable engagement.
B. More torque.
  • Our FE 8000 has almost double the torque capacity than the leading competitor.
C. Single cage design.
  • More sprags, per clutch, than any other clutch on the market.

Download our FE 8000 Case Study! See how one company partnered with our engineering team and eliminated their winch failures.

No RPM Limits: How it Works

Drawing to illustrate how a freewheel one-way sprag clutch idles to allow movement in the rotational direction.
When idle, no torque is being transmitted, the sprag assembly is rotating.

With other clutch brands, when the clutch is operating too fast the centrifugal force causes the sprags to lay down and lift off the shaft. That’s why you will see an RPM limit on their clutches.

BUT with the GMN FE 8000 sprag clutch, we don’t have that problem.

Our cam sprags are designed with a unique geometrical shape that actually uses the centrifugal forces in their favor! When centrifugal forces increase, our sprags stand up on the shaft, which produces a constant contact on the shaft at any speed (RPM). Therefore our FE 8000 has no limiting speed issues.

We know there is a “wildcard” when we talk about RPM and that’s lubrication.

So book 20 min on our engineer’s calendar and he’ll walk you through all the “geeky” details including system requirements, lead times, and pricing.

Clamping & The Engagement Curve

A single sprag on our FE 8000 sprag clutch.
engagement curve illustration of our fe 8000 series from GMN Bearing USA

The unique geometric design of the cam sprag produces a constant engagement curve.

A specific clamping angle (αa, αi) results when the sprags are in contact with the mating parts. This part of the engagement curve is called the operating zone.

Nominal Torque

For optimal torque transmission there are three key components:

  1. Stiffness of sprags, shaft and housing for minimal deflection
  2. Gap height requirements need to be met so the sprags aren’t standing up too much before engagement
  3. The line contact for Hertzian pressure needs to be tight

The rules for gap height and Hertzian pressure are:

  • Nominal torque: Gap height 8.490 mm OR Hertzian pressure of 4,200 MPa
  • Max. torque: Gap height 8.600 mm OR Hertzian pressure of 4,600 MPa

Torque Capacity

Wall thickness is the key factor for measuring stiffness in the shaft and housing. The chart below shows what happens to stress and torque limit with respect to wall thickness. We recommend a D/DL value of at least 1.4

Stress and torque limit compared to wall thickness

Application Requirements

  1. Hardened and ground mating parts
    • HRC : 60 +4
    • Surface (Rz): < 2.5 µm
    • Hardness Depth: 1.3 mm
  2. Bearing support
    • Clamping elements don’t hold concentricity
  3. Lubrication
    • No additives in your lubrication or it will prevent sprag engagement

Request a FE 8000 Quote

GMN FE 8000 Sprag Clutch Sizes & Specs

SlugSeriesPart NoSpring
Type		Shaft
Diameter
d [mm]		Outer
Diameter
D [mm]		Width
b [mm]		Torque
M [Nm]
sc-fe-8038-z16-insert-elementFE8038 Z 16Tension38.0954.7516609
sc-fe-8038-z19-insert-elementFE8038 Z 19Tension38.0954.7519801
sc-fe-8040-z16-insert-elementFE8040 Z 16Tension4056.6616668
sc-fe-8040-z19-insert-elementFE8040 Z 19Tension4056.6619880
sc-fe-8044-z16-insert-elementFE8044 Z 16Tension44.4561.1116799
sc-fe-8044-z19-insert-elementFE8044 Z 19Tension44.4561.11191052
sc-fe-8049-z16-insert-elementFE8049 Z 16Tension49.7266.3816923
sc-fe-8049-z19-insert-elementFE8049 Z 19Tension49.7266.38191201
sc-fe-8050-z16-insert-elementFE8050 Z 16Tension5066.6616942
sc-fe-8050-z19-insert-elementFE8050 Z 19Tension5066.66191237
sc-fe-8054-z16-insert-elementFE8054 Z 16Tension54.7671.42161080
sc-fe-8054-z19-insert-elementFE8054 Z 19Tension54.7671.42191424
sc-fe-8054-z25-insert-elementFE8054 Z 25Tension54.7671.42252015
sc-fe-8060-z16-insert-elementFE8060 Z 16Tension6076.66161243
sc-fe-8060-z19-insert-elementFE8060 Z 19Tension6076.66191560
sc-fe-8060-z25-insert-elementFE8060 Z 25Tension6076.66252111
sc-fe-8072-z16-insert-elementFE8072 Z 16Tension72.2188.87161740
sc-fe-8072-z19-insert-elementFE8072 Z 19Tension72.2188.87192145
sc-fe-8072-z25-insert-elementFE8072 Z 25Tension72.2188.87252918
sc-fe-8079-z-insert-elementFE8079 Z 25Tension79.6996.36253295
sc-fe-8080-z16-insert-elementFE8080 Z 16Tension8096.66161848
sc-fe-8080-z19-insert-elementFE8080 Z 19Tension8096.66192278
sc-fe-8080-z25-insert-elementFE8080 Z 25Tension8096.66253101
sc-fe-8083-z-insert-elementFE8083 Z 25Tension83.34100253640
sc-fe-8100-z16-insert-elementFE8100 Z 16Tension100116.66162632
sc-fe-8100-z19-insert-elementFE8100 Z 19Tension100116.66193303
sc-fe-8100-z25-insert-elementFE8100 Z 25Tension100116.66254535
sc-fe-8103-z16-insert-elementFE8103 Z 16Tension103.23119.89162887
sc-fe-8103-z19-insert-elementFE8103 Z 19Tension103.23119.89193582
sc-fe-8103-z25-insert-elementFE8103 Z 25Tension103.23119.89254920
sc-fe-8123-z-insert-elementFE8123 Z 25Tension123.88140.54256604
sc-fe-8126-z-insert-elementFE8126 Z 25Tension126.22142.88256744
sc-fe-8140-z-insert-elementFE8140 Z 25Tension140156.66257388
sc-fe-8150-z-insert-elementFE8150 Z 25Tension150166.66258272
sc-fe-8160-z-insert-elementFE8160 Z 25Tension160176.66259096
sc-fe-8180-z-insert-elementFE8180 Z 25Tension180196.662510463
sc-fe-8220-z-insert-elementFE8220 Z 25Tension220236.662514060
sc-fe-8123-z-insert-elementFES 8123 Z 25Tension123.34140256600