Freewheels and Backstops

Freewheels - What is it actually?

In mechanics, freewheels are couplings which act in only one direction of rotation. Freewheel couplings can transmit torques in only one direction of rotation. If the direction of rotation is reversed, freewheel clutches automatically release the connection. The same happens if the speed of the component to be driven is greater than the speed of the driving component. In this case, too, the freewheel disengages the connection and thus interrupts the transmission of the torque. MOVET offers the right overrunning clutch for every application.

What is a freewheel used for?

A freewheel is always required when a drive train is to be interrupted at a specific point in order to cause a drive torque to be transmitted in only one direction of rotation. A freewheel is also used when a predefined minimum speed must be maintained. Since freewheeling clutches are also used when specific increases in output shaft speed are desired over constant input speeds, freewheeling clutches are also referred to as "overrunning clutches." The overrunning clutch fulfills an elementary protective function for drive units by protecting them from impermissibly increased speeds and expensive mechanical damage.

Where are overrunning clutches used?

Known applications for freewheel clutches are found in the starter of internal combustion engines (starter freewheel) in combination with pulleys on alternators. Freewheel hubs are used in vehicles with engageable all-wheel drive. Freewheel clutches are also found on bicycles, namely as so-called torpedo freewheel hubs, which prevent the bicycle pedals from spinning permanently. Freewheel clutches are not only indispensable in automotive engineering. Whether in turnstiles or revolving doors, in the paper feed of copiers or in model making: Freewheel clutches can be found in many areas of our daily life. MOVET overrunning clutches are primarily used as backstops in conveyor systems, as speed compensation in transport systems or as overrunning clutches in packaging machines.

Which freewheel fits higher torques to be transmitted?

Depending on the size of the torque to be transmitted and the application, different freewheel designs are used. The most common types include sprag freewheels, centrifugal lift-off freewheels and backstops. In sprag freewheels, an outer ring and an inner ring surround a series of sprags. Sprag freewheels are geometrically designed so that they are minimally longer in the upright orientation than the distance between the inner and outer rings. As a result, the sprags are slightly tilted in the freewheeling direction. Normally, the inner ring does not follow the rotation of the outer ring. However, if the direction of rotation is changed, all sprags on the inner and outer ring will line up. This creates a clamping effect. This freewheel design is used for higher torques to be transmitted.

Which freewheel suits tasks where speed is the focus?

The so-called centrifugal lift-off freewheel designs are a special form of the sprag design. In centrifugal lift-off clutches, the sprags are shaped in such a way that they are inclined by the centrifugal force of rotation. This means that they no longer rest against the friction surfaces, which reliably prevents excessive wear. When the speed decreases again or the drive comes to a standstill, the sprags again contact the friction surface, thus enabling renewed power transmission.

Which freewheel fits if reverse running is to be prevented?

Backstops are used to reliably prevent the system from running backwards when a drive is switched off. Backstops are used, among other things, on conveyor belts and elevators in the bulk materials sector. Backstops are ideally suited when comparatively slow-running drives are to be protected. In the case of backstops, the backdriving torque generated when the drive is switched off is supported by a lever arm mounted on the outer housing of the backstop.

Is it possible to change the bearing of a freewheel?

Freilauf-Kupplungen, die einem erhöhten Verschleiß ausgesetzt sind, verfügen häufig über die Option eines Lagerwechsels. MOVET unterstützt seine Kunden durch ein umfangreiches Angebot an Freilauf Kugellagern für die angebotenen Freilauf-Kupplungen. Wenn Sie bei einem Freilauf das Lager wechseln wollen, sprechen Sie vor dem Austausch am besten mit den MOVET Experten. Gerne suchen wir gemeinsam mit Ihnen das optimale Freilauf Kugellager für Ihren Bedarf. Wir freuen uns auf Ihre Anfrage!

Buy a freewheel: Of course at MOVET!

If you want to buy a freewheel, you are in the right place at MOVET! We offer a wide selection of sprag freewheels, backstops and overrunning clutches. Our product filter makes it especially easy for you to buy the right freewheel coupling! Simply enter the required torque, bearing type and shaft diameter - and you will immediately receive a pre-sorted selection of our product portfolio. If you are looking for an overrunning clutch that is not listed on our website: No problem! We will be happy to work with you to determine the exact requirements for your project and find the optimum overrunning clutch for you. We would also be happy to advise you on the other products in our range. Just give us a call!

Freewheels and Backstops

Cam clutches - freewheels for overrunning applications with high and low speeds; bearing-mounted freewheels, backstops for the safety of your equipment

Freewheels

Backstops

Overrunning Clutches