two design styles ramp & roller overrunning clutches ·  · 2016-02-20ramp & roller design...

4 __________________________________________________ Warner Electric/Formsprag (800-927-3262) www.formsprag.com

Overrunning Clutch Designs

Ramp & Roller DesignThese rugged, reliable clutches consist ofa cylindrical outer race and an inner raceincorporating the ramps on which therollers ride. The rollers are individuallyspring loaded to provide constant forcebetween the rollers and both races. This force ensures instantaneous lock-ups when switching from the

overrunning mode to the driving mode.

This design is also quiteversatile, as the clutchcan be operated in allthree modes: overrun-ning, indexing and back-stopping. The outer racehas greater overrunningspeed capability than theinner race, making theunit ideal for use as anindexing clutch, with theouter race acting as thereciprocating member.

Ramp-Roller DesignFor increased accuracy in indexing appli-cations, specify “V” type, with strongerenergizing springs.

Two Design StylesStieber overrunning clutches are available in two basic designs:

• Ramp & Roller

• Sprag

Overrunning clutch speed is a majordetermining factor in selecting the designbest suited for each application. Ramp &roller clutches are used for applicationswith low-to-medium overrunning speedsand for indexing. Sprag clutches are thechoice for applications with high overrun-ning speeds and for backstopping.

With each basic design there are severalvariations to choose from to meet specificapplication requirements. These variationsinclude clutches with or without internalbearings, as well as a range of mountingflanges, covers and couplings.

Ball Bearing

Spring/Plunger

Seal

Locking Roller

Inner Race

Outer Race

Ramp & Roller Overrunning Clutches

Outer race

Locking roller

Inner race

Spring loadedplungers

Individually spring loaded

OverrunningDrive

DriveOverrunning

When the outer race is the driving member,this is the resultant race activity.

®

DIST. AUTORIZADOMEX (55) 53 63 23 31QRO (442) 1 95 72 60

MTY (81) 83 54 10 18ventas@industrialmagza.com

Warner Electric/Formsprag (800-927-3262) www.formsprag.com __________________________________________________ 5

Overrunning Clutch Designs

free, or overruns. Either race may be the driven member or driving member.

If one race of the overrunning clutch issecurely fixed to a grounded member, so that it cannot rotate, and the other raceis free to turn, the free race will turn freelyin one direction of rotation, but will belocked to the ground in the oppositedirection.

In an overrunning clutch, the specificsprag shapes have been developed to

Sprag DesignA sprag overrunning clutch consists of acylindrical inner race and a cylindricalouter race surrounding it, with an annularspace between the two races. A full com-plement of accurately formed sprags fillsthis annular space. Each sprag is essen-tially a strut placed between the races insuch a way that it transmits power fromone race to the other by a wedging actionwhen either race is rotated in the drivingdirection. Rotation in the other directiondisengages the sprags and the clutch is

D shape sprag design Free action PCE® design Inner race C/T design

Sprag Overrunning Clutches

Various Sprag Designs

Load Transmitting Formchrome® Sprags

Free Action Retainer

Oil Seal

Inner Race

Outer Race

Snap Ring

Lubrication Holes

Energizing Springs

Oil Seal

Snap Ring

Ball Bearings

meet most conceivable types of clutchapplications. Since different types of overrunning applications involve differentloading characteristics, different spragshapes are used to provide the greatestpossible life, torque capacity, and func-tional characteristics for the three basictypes of overrunning clutch applications:overrunning, indexing, and backstopping.

®

DIST. AUTORIZADOMEX (55) 53 63 23 31QRO (442) 1 95 72 60

MTY (81) 83 54 10 18ventas@industrialmagza.com