Drawn cup roller clutches

Drawn cup roller clutches:

are one-way clutches, which transmit torques in one direction ➤ Figure
are available with or without an integrated bearing arrangement ➤ Figure, ➤ Figure and ➤ Figure
give very precise indexing
allow high indexing frequencies
have a low overrunning frictional torque
are available with or without greasing
are particularly compact in a radial direction and therefore permit extremely compact designs
are suitable for housing materials made from steel, light metal or plastic
can be combined with drawn cup needle roller bearings with open ends HK and drawn cup needle roller bearings with closed end BK
have an extensive range of applications, for example as indexing clutches, back-stopping clutches and overrunning clutches ➤ Figure

Drawn cup roller clutches in tandem arrangement in an indexing system

Stationary component

Component performs a swivel motion

Component performs a gradual rotational motion

Product design

Design variants

Drawn cup roller clutches are available:

without bearing arrangement ➤ Figure
with bearing arrangement (rolling or plain bearing) ➤ Figure and ➤ Figure

Drawn cup roller clutches

Drawn cup roller clutches are one-way clutches

These drawn cup roller clutches comprise thin-walled, drawn outer rings with a series of ramps on the inside diameter, plastic cages and needle rollers, which serve as clamping elements. Steel or plastic springs hold the needle rollers in their clamped position. Drawn cup roller clutches can transmit high torques in one direction and are particularly compact in a radial direction. The roller clutches are available with and without support bearing arrangements.

Suitable for applications with high indexing frequencies

Drawn cup roller clutches give very precise indexing, since the individual spring loading of the needle rollers ensures continuous contact between the shaft, needle rollers and ramps. They allow high indexing frequencies due to their low mass and the resulting low moment of inertia of the clamping elements. They also have a low overrunning frictional torque.

Preferred areas of application

Drawn cup roller clutches can be used in various applications such as indexing clutches, back-stopping clutches and overrunning clutches. In these cases, the drawn cup roller clutch performs an overrunning or locking function.

Drawn cup roller clutches should not be used if a malfunction could lead to personal injury. New applications, especially those involving extreme conditions, should first be verified by tests. Correct functioning can only be guaranteed if the concentricity error between the support bearing and the shaft can be kept to a low value.

Drawn cup roller clutches without bearing arrangement

Suitable for supporting torques only

Roller clutches HF do not have a bearing arrangement, i. e. they transmit torques only and, as a result, are unable to support any radial forces ➤ Figure. In the case of these roller clutches, concentricity to the shaft axis must be secured by additional rolling bearings or drawn cup roller clutches with a bearing arrangement must be used. The drawn cup roller clutches are available with and without knurling.

Drawn cup roller clutches without knurling

Drawn cup roller clutches without knurling are available with steel or plastic pressure springs ➤ Figure. Bearings with plastic springs have the suffix KF ➤ section.

Drawn cup roller clutches with knurling

For improved torque transmission in plastic housings, drawn cup roller clutches are available with a knurled outside surface. These drawn cup roller clutches have the suffix R ➤ section. The knurling can be applied to part of the drawn cup or over its entire length. The drawn cup roller clutches are also available with steel or plastic pressure springs. Roller clutches with plastic springs have the suffix KF ➤ section.

Drawn cup roller clutches without bearing arrangement, with and without knurling

Without knurling

With knurling

Drawn cup roller clutches with bearing arrangement

Also suitable for supporting radial forces

Due to the integrated plain or rolling bearing, roller clutches HFL can also support radial forces in addition to torques ➤ Figure and ➤ Figure. The drawn cup roller clutches are available with and without knurling.

Drawn cup roller clutches without knurling

Drawn cup roller clutches without knurling are available with steel or plastic pressure springs ➤ Figure and ➤ Figure. Drawn cup roller clutches with plastic springs have the suffix KF ➤ section.

Drawn cup roller clutches with knurling

For improved torque transmission in plastic housings, drawn cup roller clutches are available with a knurled outside surface. These drawn cup roller clutches have the suffix R ➤ section. The knurling can be applied to part of the drawn cup or over its entire length. These drawn cup roller clutches are also available with steel or plastic pressure springs. Roller clutches with plastic springs have the suffix KF ➤ section.

Drawn cup roller clutches with plain bearing arrangement, with and without knurling

F_r = radial load

Without knurling

With knurling

Plain bearing

Drawn cup roller clutch with rolling bearing arrangement, without knurling

F_r = radial load

Rolling bearing

Clamping direction of the drawn cup roller clutch

An arrow on the end face of the drawn cup indicates the clamping direction of the drawn cup roller clutch. The roller clutch clamps when the drawn cup is rotated in the direction of the arrow.

Load carrying capacity

Roller clutches with a support bearing arrangement accommodate radial forces

Depending on the design (with or without bearing arrangement), drawn cup roller clutches can either transmit torques only or additional radial loads ➤ section, ➤ Figure and ➤ Figure. For roller clutches without bearing arrangement, radial forces must be supported by additional bearings.

Transmissible torque

The rigidity of the housing determines the transmissible torque

Transmission of torque requires a rigid housing. The transmissible torque is therefore dependent on the shaft and housing material, the shaft hardness, the wall thickness of the housing and the shaft and housing tolerances. When calculating the torque, the maximum drive torque and the moment of inertia of the masses during acceleration must be taken into consideration.

Limiting load

Do not exceed the limiting load

In the case of drawn cup roller clutches with plain bearings, the product calculated from the actual speed n and radial load F_R must not exceed the value stated for the limiting load (F_r · n)_max. The operating limits are determined by the limiting speeds stated in the product tables and the permissible radial load.

Indexing accuracy and indexing frequency

The roller clutch must not be overloaded

In order not to overload the clutch, the inertia of the entire system must be taken into consideration. The high indexing accuracy is due to the individual spring loading of the needle rollers, which ensures continuous contact between the shaft, needle rollers and clamping surface. The indexing accuracy is influenced by the indexing frequency, lubrication, fitting tolerances, adjacent construction, elastic deformation of the adjacent parts and the drive method, either through the shaft or the housing. Optimum accuracy is achieved if the drive is via the shaft.

High indexing frequencies due to low mass

High indexing frequencies are due to the low mass and the resulting low moment of inertia of the clamping elements.

Frictional torque and frictional energy

For pattern of frictional torque ➤ Figure. The frictional energy at idle is dependent on whether the shaft or the outer ring is rotating ➤ Figure.

Frictional torque during idling, as a function of shaft diameter

M_R = frictional torque during idling

d = shaft diameter

Frictional energy during idling, as a function of speed

N_R = frictional energy during idling

n = speed

n_GA = limiting speed with rotating outer ring

n_GW = limiting speed with rotating shaft

Rotating outer ring

Due to the centrifugal force, the needle rollers may lift off the shaft

If the outer ring rotates, the frictional energy increases with speed at first but then, due to the centrifugal force of the needle rollers, it decreases gradually towards zero. At this speed, there is no longer any frictional contact between the needle rollers and the shaft. Due to the increasing centrifugal force, the needle rollers lift off the shaft.

Compensation of angular misalignments

Concentricity is an essential precondition for correct functioning of the roller clutch. Correct functioning can only be guaranteed if the concentricity error between the support bearing and the shaft can be kept to a low value.

Lubrication

A grease to GA26 is used for initial greasing

The roller clutches are greased using a lithium soap grease to GA26. In many cases, the initial greasing is sufficient to last the operating life of the bearings. For applications with oil lubrication, roller clutches are available without greasing. These roller clutches are coated with a preservative. For general applications (mixed operation involving locking and overrunning), the Schaeffler initial greasing has proved effective. In order to ensure optimum function, it may be necessary to use different lubricants. The suitability of the lubricant must then be verified by means of tests.

For applications in which one operating condition (overrunning or locking) is heavily predominant, a special greasing should be used. In this case, please consult Schaeffler.

A grease operating life cannot be calculated

It is not possible to calculate the grease operating life or lubrication interval for drawn cup roller clutches. If relubrication is carried out, oil should used for lubrication or a changeover to oil lubrication should generally be made. At temperatures ＜ –10 °C and speeds ＞ 0,7 n_G, recommendations on lubrication should be requested. At temperatures over +70 °C, oil lubrication should be used. The oil level should be such that, when the drawn cup roller clutch is stationary and the axis is horizontal, it is immersed approx. 1/3 in the oil bath.

Suitable lubricating oils

Suitable oils are CL and CLP to DIN 51517 or HL and HLP to DIN 51524. Viscosity classes ➤ Table.

Compatibility with plastic cages

When using bearings with plastic cages, compatibility between the lubricant and the cage material must be ensured if synthetic oils, lubricating greases with a synthetic oil base or lubricants containing a high proportion of EP additives are used.

Viscosity classes

Operating temperature		Viscosity class
°C
from	to
+15	+30	ISO VG 10
+15	+90	ISO VG 32
+60	+120	ISO VG 100

Sealing

Drawn cup roller clutches (with and without bearing arrangement) are supplied without seals. Contaminants (dust, dirt and moisture) can impair the function and operating life of roller clutches.

Sealing of the bearing position with sealing rings G or SD

Effective sealing elements for use in sealing open drawn cup roller clutches with a risk of contamination

If there is a risk of contamination, sealing rings of economical series G or SD should be fitted ➤ link. The sealing rings are designed as contact seals and are arranged in front of the roller clutch. They protect the bearing position reliably against contamination, spray water and excessive loss of grease. The sealing rings are matched to the small radial dimensions of the drawn cup roller clutches and can be combined with wider inner rings of series IR. They are very easy to fit, since they are simply pressed into the housing bore.

Speeds

Speeds for rotating shaft or rotating outer ring

The limiting speeds n_GW and n_GA in the product tables are valid for oil and grease lubrication. The limiting speed n_GW is valid for a rotating shaft, while n_GAis valid for a rotating outer ring.

Noise

Schaeffler Noise Index

The Schaeffler Noise Index (SGI) is not yet available for this bearing type ➤ link. The data for these bearing series will be introduced and updated in stages.

Temperature range

Possible operating temperatures of drawn cup roller clutches ➤ Table.

Permissible temperature ranges

Operating temperature	Drawn cup roller clutches
	–10 °C to +70 °C, limited by the lubricant

In the event of anticipated temperatures which lie outside the stated values, please contact Schaeffler.

Cages

Plastic cages are used in the guidance of rolling elements for roller clutches and for integrated support bearing arrangements supported by rolling elements.

Internal clearance

The enveloping circle diameter F_w applies instead of the radial internal clearance

In the case of bearings without inner ring, the enveloping circle dimension F_w is used instead of the radial internal clearance. The enveloping circle is the inner inscribed circle of the needle rollers in clearance-free contact with the outer raceway. In drawn cup roller clutches with a rolling bearing arrangement, the enveloping circle diameter F_w of the bearings once fitted (in the solid section ring gauge) is approximately in tolerance class F8. Upper and lower deviations of enveloping circle diameter for tolerance class F8 ➤ Table.

Deviations of enveloping circle diameter for drawn cup roller clutches supported by rolling bearings

Enveloping circle diameter F_w		Tolerance class F8
mm		Tolerance for enveloping circle diameter F_w
mm		upper deviation	lower deviation
over	up to	μm	μm
3	6	+28	+10
6	10	+35	+13
10	18	+43	+16
18	30	+53	+20
30	50	+64	+25

Dimensions, tolerances

Deviations and tolerances of drawn cup roller clutches are not standardised. The thin-walled outer cups adopt the dimensional and geometrical accuracy of the housing bore.

Suffixes

For a description of the suffixes used in this chapter ➤ Table and medias interchange http://www.schaeffler.de/std/1B69.

Suffixes and corresponding descriptions

Suffix	Description of suffix
‒	Steel springs	Standard
KF	Plastic pressure springs	Standard
R	Knurled outside surface	Standard
RR	Drawn cup roller clutch with Corrotect coating	Special design, available by agreement

Structure of product designation

Examples of composition of product designation

The designation of drawn cup roller clutches follows a set model. Examples ➤ Figure and ➤ Figure.

Drawn cup roller clutch without bearing arrangement, without knurling: designation structure

Drawn cup roller clutch with bearing arrangement, plastic pressure springs, with knurling: designation structure

Dimensioning

The size is determined on the basis of the load carrying capacity of the drawn cup roller clutch relative to the loads and the requirements for rating life and operational reliability ➤ section.

Design of the adjacent construction

Design of housing bore

Support outer cup over entire circumference and width

Suitable housing materials are steel, light metal or plastic. In order to allow full utilisation of the performance capability of drawn cup roller clutches and thus also achieve the requisite rating life, sufficient rigid support must be provided for the outer cups in the housing. The support for the outer cup in the housing bore can be produced as a cylindrical seating surface. The seating surfaces for the outer cup and the raceway for the rolling elements or inner ring (if the bearing arrangement is not produced as a direct bearing arrangement) should not be interrupted by grooves, holes or other recesses. The accuracy of the mating parts must meet specific requirements, the bore tolerances for the housing bore (recommended tolerance classes) are dependent on the housing material ➤ Table and ➤ Table. The surface quality of the housing bore should be Ramax 0,8. The cylindricity tolerance of the housing bore in metal housings should be within the tolerance grade IT5/2.

Due to the thin-walled outside surface, the roller clutches only adopt their precise geometry once they have a tight fit. As a result, the accuracy of the locating bore essentially determines the geometrical accuracy of the drawn cup and thus the functioning of the clutch.

Provide lead chamfer on the housing bore

For the drawn cup roller clutches to be mounted without damage, the housing bore must have a lead chamfer of 15°.

Design of housing bore

Series	Springs	Bore
		Housing material
		Steel, cast iron	Light metal	Max. bore in plastic²⁾
HF, HFL	Steel	N6 Ⓔ (N7 Ⓔ)¹⁾	R6 Ⓔ (R7 Ⓔ)¹⁾	‒
HF..-KF, HFL..-KF	Plastic	N7 Ⓔ	R7 Ⓔ	‒
HF..-R, HFL..-R	Steel	‒	‒	D	0 -0,05
HF..-KF-R, HFL..-KF-R	Plastic	‒	‒	D	0 -0,05
HFL0606-KF-R, HFL0806-KF-R	Plastic	‒	‒	D	0 -0,05

The values in brackets can be used if the actual torque is no more than 50% of the permissible torque M_{d per} in accordance with the product table.
Guide values as a function of the plastic used. Outside diameter D ➤ link.

Minimum wall thickness for metal housings

Maximum transmissible torque

For metal housings, the maximum transmissible torque M_{d per max} is determined as a function of the diameter ratio Q_A to ➤ Figure (steel housing) or to ➤ Figure (aluminium housing), see calculation examples.

Guide values for Q_{A max} with steel and aluminium as housing materials ➤ Table.

Guide values

Housing material	Diameter ratio Q_{A max}
Steel	0,8
Aluminium	0,6

Housing material

Diameter ratio

Q_{A max}

Steel

0,8

Aluminium

0,6

The comparative stress σ_v must not exceed the yield stress of the housing material.

Steel housing

Calculation example

For drawn cup roller clutches HF0612, the maximum transmissible torque M_{d per max} should be determined ➤ Figure:

Drawn cup roller clutch	HF0612
Housing	Steel
Housing bore tolerance	N6 Ⓔ
Permissible housing stress (R_p0,2) σ_v	450 N/mm²
Diameter ratio Q_Aof housing	0,9
Permissible torque M_{d per}	in accordance with product table

Calculation

M_{d per max}
	= 60% M_{d per}
	= 0,6 * 1, 76 Nm
	= 1,056 Nm

Steel housing

Modulus of elasticity E = 210 000 N/mm²

Q_A = diameter ratio of housing

D_Ai = housing bore

D_Aa = housing outside diameter

M_{d per} = permissible torque

M_{d per max} = maximum transmissible torque

σ_v = comparative stress

Aluminium housing

Calculation example

For drawn cup roller clutch HF1616, the diameter ratio Q_A of the housing should be determined ➤ Figure:

Drawn cup roller clutch	HF1616
Housing	Aluminium
Housing bore tolerance	R6 Ⓔ
Permissible housing stress (R_p0,2) σ_v	250 N/mm²
Maximum transmissible torque M_{d per max}	10 Nm
Permissible torque M_{d per}	in accordance with product table
giving M_{d per max}/M_{d per}	50%

Calculation

Q_A	= D_Ai/D_Aa≤ 0,7
D_Aa	≧ D_Ai/0,7 = 22 mm/0,7
	= 31,5 mm

Aluminium housing

Modulus of elasticity
E = 70 000 N/mm²

Q_A = diameter ratio of housing

D_Ai = housing bore

D_Aa = housing outside diameter

M_{d per} = permissible torque

M_{d per max} = maximum transmissible torque

σ_v = comparative stress

Minimum wall thickness for plastic housing

For plastic housings, drawn cup roller clutches with a partially or fully knurled outside surface should be used (suffix R).

The guide value for the minimum wall thickness of plastic housings is:

Legend

s_min	mm	Minimum wall thickness
D	mm	Outside diameter of roller clutch
F_w	mm	Enveloping circle

Axial location

A tight fit is usually sufficient for axial location

Drawn cup roller clutches give very easy mounting and permit simple adjacent constructions. The drawn cup roller clutches are pressed into the housing bore and require no further axial location.

The precondition for this is, however, that the specifications in accordance with ➤ Table are observed.

Design of the shaft/raceway

Producing the raceway as a rolling bearing raceway

Drawn cup roller clutches HF/HFL are usually used without an inner ring. In order to guarantee correct functioning of the drawn cup roller clutches, the raceway for the rolling elements on the shaft must be produced as a rolling bearing raceway (hardened and ground). The surface hardness of the raceways mus be 670 HV to 840 HV, the case hardening depth CHD must be sufficiently large (CHD ≧ 0,3 mm). Design of raceways ➤ Table. If the shaft cannot be produced as a raceway, the bearings can be combined with inner rings IRor LR.

Provide lead chamfer on the housing bore

For the bearings to be mounted without damage, the shaft must have a lead chamfer of 10° to 15° with a width of approx. 1 mm.

Design of shaft

Series	Springs	Shaft
		Tolerance class¹⁾	Roundness tolerance	Parallelism tolerance	Recommended mean roughness value
			Roundness tolerance	Parallelism tolerance	Ramax (Rzmax)
			max.	max.	μm
HF, HFL	Steel	h5 (h6)²⁾	IT3	IT3	0,4 (2)
HF..-KF, HFL..-KF	Plastic	h8
HF..-R, HFL..-R	Steel	h5 (h6)²⁾
HF..-KF-R, HFL..-KF-R	Plastic	h8
HFL060t6-KF-R, HFL0806-KF-R	Plastic	h9

The envelope requirement Ⓔ applies.
The values in brackets can be used if the actual torque is no more than 50% of the permissible torque M_{d per}.

Mounting and dismounting

Protect drawn cup roller clutches against dust, dirt and moisture; contaminants can impair the function and operating life of roller clutches. Pressing-in forces must never be directed through the rolling elements. Drawn cup roller clutches must not be tilted during pressing-in, as this may damage the needle rollers and raceways.

Retention for transport

Drawn cup roller clutches are normally packed individually in the case of small quantities. Where larger quantities are involved, drawn cup roller clutches are placed in a specific orientation in blister packaging and delivered in this form. The blister packaging then serves to retain the parts in position during transport.

Removing the drawn cup roller clutches from the packaging

Drawn cup roller clutches should only be removed from their original packaging immediately before assembly. If roller clutches are removed from a batch packaged with dry preservative, the package must be closed again immediately. The protective vapour phase can be maintained only in the closed package. Ungreased drawn cup roller clutches are coated with a preservative. Lubrication with oil must take place after pressing-in, in accordance with the specifications.

Storage

Drawn cup roller clutches should be stored:

in dry, clean rooms with the room temperature as constant as possible
at a relative humidity of max. 65%

Storage period

The storage period for greased drawn cup roller clutches is limited by the shelf life of the lubricating grease.

Mounting using a fitting mandrel

Drawn cup roller clutches should only be pressed into the locating bore using a special fitting mandrel. Attention must be paid to the clamping direction of the roller clutch. The clamping direction is indicated by an arrow on the end face of the drawn cup.

The drawn cup roller clutch clamps if it is rotated in the direction of the arrow.

Functional inspection

Clutches without knurling

The function of these roller clutches is checked in a housing with the minimum wall thickness determined according to ➤ Figure or thicker. The housing bore and shaft tolerances must be observed ➤ Table and ➤ Table.

Clutches with knurling

The function of these clutches is checked before they are pressed in. In this case, the inspection criteria are the clamping effect and idling.

For any questions relating to the mounting of drawn cup roller clutches, please consult Schaeffler.

Schaeffler Mounting Handbook

Drawn cup roller clutches must be handled with great care

In order that drawn cup roller clutches can function correctly and achieve the envisaged operating life without detrimental effect, they must be handled with care.

The Schaeffler Mounting Handbook MH 1 gives comprehensive information about the correct storage, mounting, dismounting and maintenance of rotary rolling bearings http://www.schaeffler.de/std/1B68. It also provides information which should be observed by the designer, in relation to the mounting, dismounting and maintenance of bearings, in the original design of the bearing position. This book is available from Schaeffler on request.

Legal notice regarding data freshness

The further development of products may also result in technical changes to catalogue products

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We therefore reserve the right to make changes to the data and illustrations in this catalogue. This catalogue reflects the status at the time of printing. More recent publications released by us (as printed or digital media) will automatically precede this catalogue if they involve the same subject. Therefore, please always use our electronic product catalogue to check whether more up-to-date information or modification notices exist for your desired product.