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FXN series

FXN series
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Internal Freewheels FXN for press fit on the outer ring with sprag lift-off X Application as ➧ Backstop ➧ Overrunning Clutch For application as backstop in installations with high speeds in freewheeling operation. For application as overrunning clutch in installations with low speeds in driving operation. Features Internal Freewheels FXN are sprag freewheels without bearing support and with sprag lift-off X. The sprag lift-off X ensures a wear-free freewheeling operation when the inner ring rotates at high speed. The outer ring is pressed into the customer housing. This makes compact, space-saving fitting solutions possible. Nominal torques up to 20 500 Nm. The torque is transmitted on the outer ring by press fit. Bores up to 130 mm. A multitude of standardized bore diameters are available with short delivery times. Sprag lift-off X Internal Freewheels FXN are equipped with sprag lift-off X. The sprag lift-off X is used for backstops and overrunning clutches, provided that in freewheeling operation the inner ring is rotating at high speed and providing with overrunning clutches that the driving operation is conducted at low speed. In freewheeling operation, the centrifugal force FC causes the sprag to lift off from the outer track. In this operating state, the freewheel works wear-free, i.e. with unlimited service life. Figure 74-2 shows a freewheel with sprag liftoff X in freewheeling operation. The sprags, which are supported in a cage connected with the inner ring, rotate with the inner ring. The centrifugal force FC that is applied in the center of gravity S of the sprag turns the sprag counterclockwise and rests against the support ring of the cage. This results in the gap a between the sprag and the outer track; the freewheel works without contact. If the inner ring speed decreases to such an extent that the effect of Support ring Freewheeling direction or freewheeling operation Locking direction or driving operation the centrifugal force on the sprag is less than that of the spring force FF , the sprag again rests on the outer ring and the freewheel is ready to lock (figure 74-3). If used as an overrunning clutch, the driving speed must not exceed 40% of the lift-off speed

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Internal Freewheels FXN for press fit on the outer ring with sprag lift-off X Application example Internal Freewheel FXN 38 - 17/70 NX as a backstop, arranged in a housing adapter to attach to an electric motor. The thin outer ring that is pressed into the housing enables a space-efficient fitting solution. Due to the high shaft speeds in normal operation (freewheeling operation), the sprag lift-off X ensures a contactless and hence wear-free continuous operation. Application example Application example Internal Freewheel FXN 85 - 40/140 MX as a backstop fitted to the end of the first...

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Internal Freewheels FXNfor press fit on the outer ring with sprag lift-off X Backstop The maximum transmissible torque is 2 times the specified nominal torque. See page 14 for determination of selection torque. The theoretical nominal torque applies only for ideal concentricity between the inner and outer ring.In practice, the concentricity is affected by the bearing play and centering errors of the neighbouring parts. Then the nominal torques specified in the table apply, whilst taking into consideration the existing run out (T.I.R.). Higher speeds upon request. Mounting Internal...

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Internal Freewheels FXNfor press fit on the outer ring with sprag lift-off X 77-1 Freewheel size Internal Freewheels ■ Freewheels with bore diameters highlighted blue in the table are available with short delivery times. Keyway according to DIN 6885, page 1 • Tolerance of keyway width JS10. * Keyway according to DIN 6885,page 3 • Tolerance of keyway width JS10. Lubrication At speeds in excess of the sprag lift-off speed, no special lubrication is required; the freewheel functions maintenance-free. When operating below the sprag lift-off speed, an oil lubrication of the specified quality...

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