Standard SKF

8/21/2019 Standard SKF

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Roller screws


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Se

Hi

Gl


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General

Other technical dataLead precision according to ISO ---------------------------------------------------------------Preload adjustment --------------------------------------------------------------------------------Product inspection and certification ----------------------------------------------------------

GeneralOverview: roller screw nuts ---------------------------------------------------------------------Comparing roller screws to ball screws ------------------------------------------------------The principle of planetary roller screws -----------------------------------------------------The principle of recirculating roller screws -------------------------------------------------

Recommendations for selectionBasic and static load rating ---------------------------------------------------------------------

Critical rotating speed for screw shafts ------------------------------------------------------Permissible speed limit --------------------------------------------------------------------------Lubrication ------------------------------------------------------------------------------------------Efficiency and back-driving ---------------------------------------------------------------------Axial play and preload ----------------------------------------------------------------------------Static axial stiffness --------------------------------------------------------------------------------Screw shaft buckling ------------------------------------------------------------------------------Materials and heat treatments -----------------------------------------------------------------Shaft design -----------------------------------------------------------------------------------------

Recommendations for assemblyRadial and moment loads -----------------------------------------------------------------------Alignment --------------------------------------------------------------------------------------------Lubrication -------------------------------------------------------------------------------------------Designing the screw shaft ends ---------------------------------------------------------------Starting-up the screw ---------------------------------------------------------------------------Operating temperature --------------------------------------------------------------------------

Rollingelement

Load CoØ

d

Product informationService Range Capabilities -------------------------------------------------------------------------------------------Range details ----------------------------------------------------------------------------------------Flanged thrust bearings, FLRBU --------------------------------------------------------------

Standard Range Pl t ll t h i l d t d di i


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General

Overview

nuts for r

Planetary roller screws


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General

TRU/PRUCylindrical backlash elimination: TRU Preloaded: PRU

SRC, Cylindrical axial play BRC, backlash elimination

TRK/PRK Flanged backlash elimination: TRK Preloaded: PRK

SRF, Flanged axial playBRF, backlash elimination

PVU Cylindrical preloaded

SVC, Cylindrical axial play BVC, backlash elimination


6/88

General

The load carrying capacity of arolling screw depends practicallyon the surfaces at the points ofcontact:

n their diametern the number of contactsn their hardnessn their surface fi nish

n the preassurethem.

Comparing roller screws to ball screws

Roller screws

In roller screws, the load is transmitted from the nubarrelled surfaces of all the engaged rollers. The diameter of the contact surface is substantially of points of contact.

2 types of roller screws

Planetary roller screwThreaded rollers are the basis of“SR / BR / TR / PR” planetary roller screws.

RecirculatinGrooved roll“SV /BV / PV

Contact surfaces

Diameter

Number

Hardness

Surface finish

Precision

Load rating

EE===

E E

=====

=

Ball screws

In ball screws, the load is transmittedfrom the nut to the shaft through theballs engaged in the groove.

In a single start ball screw, the balldiameter is limited to approximately70 % of the lead: there is only a singlehelix of balls in a nut of given lengthso the number of contacts is small.


7/88

General

Higheracceleration over

12 000 rad/sec2

Stainless steels

Higher statload up to1000 tonne

Hiloa20

Higher rospeed Ø 4over 300

Shock loads

Adverseenvironmentsdust, ice, sand

1 mm Lead

SRSV SRSV

SV

SR

SRSR

SR

SR

SV

Break out from the limitations of

ball screw performance

The 10 reasonsfor using roller screws


8/88

Many strong contact surfaces High load carrying capacity

No recirculation and no contact No weak points in the nut between rolling elements High rotation speed

Guided rollers No loss in preload torque when changing direction

Timing mechanism Exceptional reliability

Adaptable tooling Non standard and left hand leads available

All parts made “in house”, special steels possible

General

The capacity to carry heavy loadsf th d f h i th

Examples:Pl ti ldi

The principle of planetary roller screws

Threaded rSR/BR/TR/

fig. 1

The specific qualities of SKF planetary roller screws

Typical applications

G l


9/88

General

Ultimate positioning accuracy canb bt i d i th fi l d

Examples:G i di hi

The principle of recirculating roller screws

Grooved rollerrecirculating r

fig. 1

The specific qualities of SKF recirculating roller screws

Very small leads (1mm) Fine resolution Minimum drive torque High m

No miniature parts Simple Robust Reliab

Many strong contact Heavy load High rigidity Long

points carrying capacity

All parts made “in house”, special steels possible

Typical applications

R d ti f l ti


10/88

Recommendations for selection

Basic dynamic loadrating (Ca)

The dynamic rating is used tocompute the fatigue life of roller

screws. It is the axial load cons-tant in magnitude and direction,and acting centrally under whichthe nominal life (as defi ned byISO) reaches one million revolu-tions.

Nominal fatigue life L10The nominal life of a roller screwis the number of revolutions(or the number of operatinghours at a given constant speed)which the roller screw is capableof enduring before the fi rst signof fatigue (fl aking, spalling) occurson one of the rolling surfaces

(screw, nut or roller thread orgroove).

It is however evident fromboth laboratory tests and practi-cal experience that seeminglyidentical roller screws operatingunder identical conditions have

different lives, hence the notion ofnominal life. It is, in accordance with ISO

defi nition, the life achieved orexceeded by 90 % of a suffi cientlylarge group of apparently identi-cal roller screws, working in iden-tical conditions (alignment, axial

and centrally applied load, speed,acceleration, lubrication, tempe-rature and cleanliness).

Service It is the aspecifi c rFailure is(fl aking oinadequawear of tcorrosion

more genfunctionaby the ap

Expersimilar apselect thethe requimust tak

requiremof screw ments, duthe elemL10 life pworking is permit


Only basic selection parameters are included. To make the verybest selection of a roller screw, the designer should specify suchcritical parameters as the load spectrum, the linear or rotationalspeed, the rates of acceleration and deceleration, the cycle rate,the environment, the required life, the lead accuracy, the stiffness,and any special requirement. If in doubt, please consult an SKFspecialist before placing an order.

In cases where more than 90 %



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Equivalent dynamic loadsThe loads acting on the screwcan be calculated according to the

laws of mechanics if the externalforces (e.g. power transmission,work, rotary and linear inertiaforces) are known or can be cal-culated. It is necessary to calcula-te the equivalent dynamic load(see page 84). Radial and moment loadsmust be taken by linear guidingsystems. It is extremely importantto resolve these problems at theearliest conceptual stage. Theseforces are detrimental to the lifeand the expected performance ofthe screw.

Fluctuating load

When the load fl uctuates duringthe working cycle, it is necessaryto calculate the equivalent dyna-mic load: this load is defi ned asthat hypothetical load, constant inmagnitude and direction, actingaxially and centrally on the screwwhich, if applied, would have thesame infl uence on the screw lifeas the actual loads to which thescrew is subjected.

Additional loads due, forexample to misalignment, unevenloading, shocks, and so on, must

be taken in account.Their infl uence on the nominallife of the screw is generally takencare of, consult SKF for advice.

Static load carryingcapacity (Coa)

Roller screws should be selectedon the basis of the static loadrating Coa instead of on life whenthey are submitted to continuousor intermittent shock loads, whilestationary or rotating at very lowspeed for short duration.

The permissible load is deter-mined by the permanent defor-mation caused by the load actingat the contact points.

It is defi ned by ISO standardsas the purely axially and centrallyapplied static load which willcreate, by calculation, a total (rol-

ling element + thread surface)permanent deformation equal to0.0001 of the diameter of curva-ture of the rolling element. Thisdeformation corresponds to acontact Hertz stress up to 4500MPa depending on the screw dia-meter.

The roller screw must beselected by its basic static loadrating which must be, at least,equal to the product of the maxi-mum axial static load applied anda safety factor “so”.

The safety factor is selected inrelation with past experience of

similar applications and require-ments of running smoothnessand noise level (1).

Critical rfor screw

The shaft isthe diametediameter ofmulas (seemeter the vdictated by screw shaft

supported oAs a ruledered as a sshaft. Becauinaccuraciesthe screw ator of 0.80 culated criti

Calculatithe nut as aor reduce thre practical optimization



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Permissible speed limit

The permissible speed limit isthat speed which a screw cannotreliably exceed at any time. It isgenerally the limiting speed ofthe centrifugal forces in the nut.It is expressed as the product ofthe rpm and the diameter of thescrew shaft (in mm). The speed limits quoted in thiscatalogue (see page 84) are themaximum speed that may beapplied through very short periods and in optimized running condi-tions of alignment, light externalload and preload with monitoredlubrication.

Running a screw continuouslyat the permissible speed limitmay lead to a reduction of thecalculated life of the nut mecha-nism.

High speed associated withhigh load requires a large inputtorque and yields a relativelyshort nominal life (1). In the case of high accelera-tion and deceleration, it is recom-mended to either work under anominal external load or to apply

a light preload to the nut to avoidinternal sliding during reversal.The value of the preload of

screws submitted to high accele-ration is that preload whichensures the rolling elements do

Lubrication

The key point is the initial lubri-cation of the nut to lubricate allcomponents. The lubrication ofscrews rotating at high speedmust be properly considered inquantity and quality.

The volume, spread and fre-quency of the application of thelubricant (oil or grease) must beproperly selected and monitored.At high speed the lubricantspread on the surface of thescrew shaft may be thrown off bycentrifugal forces. It is important

to monitor this phenomenonduring the fi rst run at high speedand possibly adapt the frequencyof re-lubrication or the fl ow oflubricant, or select a lubricantwith a higher viscosity.

Monitoring the steady tempe-rature reached by the nut permits

the frequency of re-lubrication orthe oil fl ow rate to be optimized.

Oil lubr

A centraloil systemcontinuothe nut wfrom the prescribeis likely taccuracy. regulatedkness an

SelectionMineral olubricate such as bmay be u

viscosity the speedand load.a viscositrunning tin viscosithe runnispeed (<

should bening temload an Ethe fi lm ded. Corrstabilizinused to a Synth

advised frature. Bariumheavy loaadhesion

!



13/88


Grease lubrication

Where oil lubrication is not prac-ticable, the grease recommendedfor the support bearings of thescrew may also be used for thescrew. After a few full strokes thegrease will be spread evenly overthe useful threaded length ofthe screw shaft, which will alsohelp to protect the screw againstcorrosion. However the grease isopen to the air.

To prevent dirt which mayfall on it from entering the nut,wipers should be mounted ineach end of the nut. Also thegrease on the screw shaft willage more quickly than that in thescrew support bearings so morefrequent regreasing is needed,especially in a dirty environment.If the screw cannot be dis-mounted and cleaned beforeregreasing it is necessary tothoroughly clean the old grease

from the screw shaft. This canbe done with a spatula and thenwith a clean fl uff proof cloth.To clean even more a cloth wet-ted with a solvent such as whitespirit may be used. We do notadvise using brushes to removeold or spread new grease (risk of

bristles coming out). Apply alsothe new grease through the nutto push out the old from insidethe nut. The grease type is defi nedabove all by the operating tem-

Selection of greaseLithium base greases, for stan-dard applications with EP-additi-

ves, are generally suitable for usefrom –30 °C to +110 °C.

A few can be used to +150 °CLithium base greases are virtuallyinsoluble in water and very workstable. However they absorblarge quantities of water whenworked to extremes.

Lubrication intervalThe lubrication interval dependson the working cycle of the screwand whether the lubricant is pol-luted during use. General adviceis diffi cult but the following willhelp you to defi ne the interval.On start up check the greasequality regularly, for instanceevery month. The fi rst re-lubrication has tobe done after roughly 50 000revolutions under load, toremove all particles generatedduring running-in. If the viscosity of the greasesample has increased, it needsreplacing. If the grease sample is darkerthan new it may indicate oxida-tion or the presence of metallicparticles.

If it is discoloured, it is proba-bly mixed with water. It is helpful to take samplesnot only from the part of thescrew where running has occu-red but also from unused partsf h h h



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Quantity of lubricant

• OilWe advise a quantity of5 › 25 cm3/h in shots of 0,1 cm3 as an order of magnitude depen-ding on the size of the screw andits running conditions.

• GreaseThe total volume of grease nee-ded for a new roller screw is thesum of the quantities needed forthe screw shaft and the nut. The volume of grease neces-sary for the screw shaft Zs canbe estimated from this formula:

This quantity of greaseshould be spread over the wholethreaded length of the shaft. The

volume of grease for the nut Zn is one third of the free volume inthe nut.

The quantity Zn is given in thedimension tables: it should beinjected through the lubricationhole while turning the shaft. Before applying load the nut

should be run twice along thecomplete stroke to ensure greaseis evenly spread.

Relubrication, see also ‘Greaselubrication’

Efficiency and back-driving

The performance of a screw ismainly dependant on the geo-metry of the contact surfaces andtheir fi nish as well as the helixangle of the thread.

It is, also, dependant on theworking conditions of the screw(load, speed, lubrication, preload,alignment, etc…). The “direct effi ciency” is usedto defi ne the input torque requi-red to transform the rotation ofone member into the translationof the other. Conversely, the“indirect effi ciency” is used todefi ne the axial load required to

transform the translation of onemember into the rotation of theother one. It is used, also, to defi -ne the braking torque required toprevent that rotation. These screws are reversible orback-driveable under almost allcircumstances. It is therefore

necessary to design a brakemechanism if backdriving is to beavoided (gear reducers or brake).

Preload t

Internallybit a torq

This persnot extertorque is when assISO grad

Starting

This is de

ded to ovstart rotaa) the totparts accsource (inlinear mob) the intscrew/nuassociate In geninertia (atorque (b The cothe high starting µdouble thunder no

Zs = 4,4 ™ 10

-4 d0l1



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Axial play and preload

Preloaded nuts are subject tomuch less elastic deformationthan non-preloaded nuts.

Therefore they should be usedwhenever the accuracy of positio-ning under load and stiffness areimportant.

Preload, preload torqueand rigidity

When a roller screw with a wholenut with axial play is measuredon a tensile testing machine, agraph similar to (fi g. 1) is obtai-ned. One objective of preloadingis to eliminate the axial play sothat positioning accuracy isimproved when the external loadchanges direction.

Planetary roller screws areavailable with play eliminationusing whole nut (designation: BR)or split nut (designation: TR). In this case the preload torquewill be between 0 and Tpe measu-red at 50 rpm when lubricatedwith ISO grade 68 oil.

Planetary and recirculatingroller screws are also availablepreloaded for optimum rigidity:their designations are PR and PV.(fi g. 2) shows how a squeeze loadFq is applied to the nut halves 1and 2 of a split nut to obtain apreload Fpr . One part of this loadis used to generate the preloadf d h h

When an external load F (fi g. 3) isapplied the loads on the nut hal-ves become F1 and F2.

For all conditions whereF ≤ 2,83 Fpr the load seen by nuthalf 2 is greater than the externalload so increasing the preloadreduces the life of the screw.When the external load reaches2,83 Fpr nut half 1 is unloadedand F2 = F. Roller screws are

normally preloaded by preloadingone nut half against the other soonly one half supports the exter-nal load in a given direction. Inthis case, nut half 2 is taking theexternal load. The load carryingcapacity and rigidity of a splitpreloaded nut are substantiallyless than a whole nut.

Because of the very high loadcapacity and rigidity of rollerscrews a split nut is suffi cient formost applications and offers anextremely compact design.

-- 1- 20- 30

-

- 1

- 1

1

1

fig. 1

Fq

Fpr

fig. 2

Fq

F1

fig. 4

fig. 3



16/88


Figure 5 compares the load/defl ection characteristics of threedifferent nut combinations:

Curve 1. Whole nut with axialplay

Curve 2. Preloaded split nutCurve 3. Preloaded double nut. Backlash elimination can beachieved by fi tting oversize rollersin one-piece nut (BRC-BVC)which allows to keep high load

capacities. In exceptional cases where theload rating of a split nut is notsuffi cient two whole cylindricalnuts may be preloaded together(fi g. 6). Exact dimensions areavailable on request: please con-tact SKF.

The squeeze load applies acompressive preload in all cases:this ensures more rigidity of the

roller screw compared to a pre-load in extension. Preload torque is the torqueresulting from the preload, Fpr.The preload torque is calculatedfrom the nominal preload assu-ming a real effi ciency of 90 % ofthe theoretical direct effi ciency

(page 85).

The prelo

+

10000

15000

LoadN 3 1

2

fig. 6fig. 5

Tpr = F



17/88

Preload torque tolerancesFor each roller screw, preloadedfor optimum rigidity a range of

value of preload torque , Tpr isgiven in the technical data. Thecustomer is free to choose anyvalue in this range: if no value isspecifi ed on the order the meanvalue will be taken. A typical pre-load torque graph is shown onpage 18: they can be obtained on

request when ordering. The reference Rnr value ofrigidity correspond to this meanpreload torque value.

The tolerance of variation ofpreload torque as the nut movesalong the length of the screwdepends on the helix angle of thescrew thread, the slenderness ofthe screw shaft and the lead pre-cision. The tables give the tole-rances of preload torquevariation. Refer to A if the helixangle, a is less than 11° and B ifit is more. Preload torque is measured at50 rpm with ISO grade 68 oil forSR/TR/PR screws and with ISOgrade 220 oil for SV/PV screws.

A. Tolerance of preload torque for screws with a < 1

l1/d0 ≤ 40 and l1 ≤ 4000 l1/d Tpr G1 G3 G5 G Nm ±%

≤0,2 35 40 50 4 (0,2) - 0,6 25 30 35 3 (0,6) - 1,0 20 25 30 2 (1,0) - 2,5 15 20 25 2

(2,5) - 6,3 10 15 20 1 (6,3) - 10,0 10 10 15 1

B. Tolerance of preload torque for screws with a ≥ 1

l1 ≤ 2000 2000

Tpr G3 G5 G3 Nm ±%

0 - 10,0 70 80 80

Planetary roller screws preloaded for optimum rigidity wavailable in G1 lead precision.



18/88

Example:

A PRK 48 ™ 10 with threaded length 600 mm. The range of preloadtorque is 1,24 › 2,47 Nm. What is the tolerance of preload torque forG3 lead precision ?

The minimum guaranteed nut rigidity is 760 N/µm and the refe-rence value is 980 N/µm. To obtain these the mean value of preloadtorque is specified: 1,855 Nm. The helix angle a is 3,79°.

Table A gives ±20 % for G3. All screws will be within the tolerance

1,855 ±20 % or 1,484 › 2,226 Nm.

If for reasons of motor torque limitations the minimum preloadtorque 1,24 Nm is chosen. The tolerance becomes 1,24 ±20 % or0,99 › 1,49 Nm and the preload and minimum guaranteed and refe-rence values of rigidity are not valid.

Two typical examples are shown. 1,81,6

1,41,2

1,0

0,8

TprNm

0,2

fig. 2

2,42,2

2,0

1,8

1,6

1,4

1,2

1,0

TprNm

0,2

fig. 1



19/88

Static axial stiffness of acomplete assembly

It is the ratio of the external axialload applied on the system andthe axial displacement of the faceof the nut in relation with thefi xed (anchored) end of the screwshaft. The inverse of the rigidityof the total system is equal to the

sum of all the inverses of therigidity of each of the compo-nents (screw shaft, nut as moun-ted on the shaft, supportingbearing, supporting housings,etc…).

Because of this, the rigidity ofthe total system is always lessthan the smallest individual rigi-

dity.

Nut rigidity: RnWhen a preload is applied to asplit nut, fi rstly, the internal playis eliminated, then, the Hertzianelastic deformation increases asthe preload applied so that the

overall rigidity increases. The theoretical deformationdoes not take into accountmachining inaccuracies, actualsharing of the load between thedifferent contact surfaces, the

Shaft rigidity: RsThe elastic deformation of screwshaft is proportional to its length

and inversely proportional to thesquare of the root diameter. According to the relativeimportance of the screw defor-mation (see rigidity of the totalsystem), too large an increase inthe preload of the nut and sup-porting bearings yields a limited

increase of rigidity and notablyincreases the preload torqueand therefore the running tem-perature.

Consequently, the preload sta-ted in the catalogue for eachdimension is optimum and shouldnot be increased.

for standard steelsee fi g. 1

for standard steelsee fi g. 2

Screw shThe columnshaft must bsubmitted t(whether dyly).

The maxcompressiveusing the Ethen multipof 3 to 5, deapplication.

Th t

fig. 2

fig. 1

1 = 1 + 1 Rt Rs Rn

d2

2

Rs = 165 ––– (N/µm)l

165 d22 l

Rs = ––––––––––––––l2 (l - l2)



20/88

Materials and heattreatments

Standard screw shafts aremachined from pretreated42 CrMo4.

Standard nuts are machinedin 100Cr6 steel which is throughhardened. Hardness of the con-tact surfaces is 56-60 HRc. Most assemblies made ofstainless material have a surface

hardness in the range 42 to 58HRc: the load rating of the cata-logue therefore must be deratedrespectively to C’a and C’oaC’a and C’oa being the capacitieswith the new hardness in Vickers(Hv).

Working environment

Our products have not beendeveloped for use in an explosiveatmosphere, consequently wecannot take any responsibility for

their use in this fi eld.NOTE: 42 CrMo4, an AFNORreference is similar to AISI 4140;100Cr6 is similar to AISI 52100.

Shaft D

It is possiscrews wthe outsidshaft. To

ciently anmeter d2(fi g. 1).

• When d

SR/BR/TPh ≤ 8 m

Ph > 8 m

SV/BV/PVPh = 1+ 40 ™ 263 ™ 2

Through hardening treatment

Tensile strength,MPa

Yield stress(Rp 0,2 %)

850 MPa

650 Mpa up to12,5 mmradially fromoutside.550 MPa morethan 12,5 mmradially fromoutside.

Then the Transrol thread is surface

hardened by induction.

( Hv )

2

C’a = Ca ™ ––––– 654

( Hv )3

C’oa = Coa ™ ––––– Recommendations for selection


21/88

Zone A.Torsion only

The nominal shear stress t cau-sed by the drive torque T is givenby:

16 Tt = ––––––– p d5

3

This is increased by a stress con-centration factor f 4 to give thereal shear stress, tp

tp = f 4t

According to Von Mises the total

stress, st

st = 1,73 tp

For safety st should be less than67 % of the 0,2 % proof stress ofthe steel.

If the end diameter d5 inclu-

des a keyway of depth e calculatewith (d5 - e).

The angle of twist of the screwshaft is given by

0,0648 Tlq = ––––––––––

do4

The linear positioning error, d,caused by this twist

Ph q

Zone B.Axial + torsional stresses

The nominal axial stress causedby the axial load F is given by

4Fs = ––––– pd4

2

This is increased by a stress con-centration factor f 5 to give thereal principal stress sp

sp = f 5 s

as above

tp = f 4t

According to Von Mises the totalstress st

st = (sp2 + 3 tt

2)1/2

For safety st should be less than

67 % of the 0,2 % proof stress ofthe steel.

Strengthends

The end ma

screw is desmer. Due todynamic loascrews it is the strengthends.

This cheresponsibilit

cally ask SK This siminto accounters of the ecentration fit takes intoaxial and to

d5 r5

ZONE A

fig. 1



22/88

Manufacturing precision

Generally speaking, the precision

indication given in the designa-tion defi nes the lead precision:see page 24. Lead precision according toISO (ex. G1 - G5…). Parameters other than leadprecision correspond to our inter-nal standards (generally based onISO 3408-3 class 5). If you require special toleran-ces (for example class 1 or 3)please specify when requesting aquotation or ordering.

Inspection of surface finish

Recommendations for assembly


23/88

Radial and moment loadsAny radial or moment load on thenut will overload some of thecontact surfaces, thus signifi cantlyreducing its life. (fi g. 1)

AlignmentSKF linear guidance componentsshould be used to ensure correctalignment and avoid non-axialloading. The parallelism of thescrew shaft with the guidingdevices must be checked.

If external linear guidanceprove impractical, we suggestmounting the nut on trunnions orgimbals and the screw shaft inself-aligning bearings. Mounting the screw in tensionhelps align it properly and elimi-nates buckling.

LubricationGood lubrication is essential forthe proper functioning of thescrew and for its long term relia-bility (1) (see fig 2)

If this operation is performedin a potentially polluted atmos-phere it is highly recommendedto proceed with a thorough clea-ning of the assembly.

Designing the screw shaft endsGenerally speaking, when theends of the screw shaft are spe-cifi ed by the customer’s enginee-ring personnel, it is theirresponsability to check thestrength of these ends.

Roller screws can be suppliedwith one end bigger than the dia-meter of the threaded portion.The core strength of such an endmay be affected by large reduc-tions of diameter. When this con-cept of a large end is used, aminimum length at root diameter

is needed between the end of thethread and the face of the largerdiameter.

Starting-up the screwAfter the assembly has been

Operating tScrews mad(see page 2under normtemperaturto +110 °C. BetweenSKF must b

adapts the and checks can be succbelow the svalue. Above +adapted to the applicat

ted, which cload rating. Consult

NOTE:Operating awill lower thsteel, alter t

thread and dability of t

Recommended assembly procedure

YESfig. 1

Roller screws are precision components and should be handledwith care to avoid shocks. When stored out of the shipping cratethey must lie on wooden or plastic vee blocks and should not beallowed to sag. Screw assemblies are shipped in a carboard/wooden crate,wrapped in a sealed plastic bag which protects them from foreignmaterial and possible pollution. They should stay wrapped until

they are used.

Technical data


24/88

Lead precision according to ISO

Lead precision is measured at 20 °C on the useful stroke lu, which isthe threaded length decreased, at each end, by the length le equal tothe screw shaft diameter.

G1 G3 G5

V300p µm 6 12 23

lu ep vup ep vup ep vup mm µm

0 - 315 6 6 12 12 23 23 (315) - 400 7 6 13 12 25 25 (400) - 500 8 7 15 13 27 26 (500) - 630 9 7 16 14 32 29 (630) - 800 10 8 18 16 36 31 (800) - 1000 11 9 21 17 40 34

(1000) - 1250 13 10 24 19 47 39 (1250) - 1600 15 11 29 22 55 44 (1600) - 2000 18 13 35 25 65 51 (2000) - 2500 22 15 41 29 78 59 (2500) - 3150 26 17 50 34 96 69 (3150) - 4000 32 21 62 41 115 82 (4000) - 5000 76 49 140 99 (5000) - 6300 170 119

Technical data


25/88

le le

m

Threaded length

l u

c

+

l0mm

fig. 2

Threaded length

lule

fig. 3

Threaded length

l e l u

300 mm

v

Mean travel :the line which fitsthe curve best bymethod of leastsquares.

300a

v300p

fig. 1

Case with value of c specified by the customer. Case with c = 0 = standard veno value given by the custome

lu = useful travel

le = excess travel (no lead precision required)

lo = nominal travel

ls = specified travel

c = travel compensation (difference between ls and lo

to be defined by the customer, for instance to

compensate for expansion)

ep = tolerance over the specified travel

V = travel variation (or permissible band width)

V300p = maximum permitted travel variation over 300 mm

Vup = maximum permitted travel variation over the useful

travel luV300a = measured travel variation over 300 mm

Vua = measured travel variation over the useful travel

Technical data


26/88

Preload adjustment

Cylindrical nutsIn the case of cylindrical nuts (types TRU and PRU for planetary rollerscrews - type PVU for recirculating roller screws), the threadedhousing stoppers must be tightened to the values shown into tables 1and 2 below. These torques can also be used with one-piece nuts(SRC - BRC - SVC - BVC).

The standard nut is through hardened to 56 d 60 HRc: under some load conditions itis necessary to use hardened & ground spacers (S) to avoid bedding of the nut into thehousing & stopper resulting in loss of preload and rigidity.

SVC/BVC/PVU

Housing stopper Tightening Squeeze thread torque load

d1 mm Nm Nd1 mm Nm N

Table 2

SRC/BRC/TRU/PRU

Housing stopper Tightening Squeeze thread torque load

d0 mm Nm N

8 12

15 21 25 30 39 44 48 60 64

75 80 99 120 150

30 ™ 1.0 35 ™ 1.0

40 ™ 1.0 50 ™ 1.0 60 ™ 1.0 70 ™ 1.5 90 ™ 1.5 88 ™ 1.5 110 ™ 1.5 130 ™ 2.0 125 ™ 2.0

158 ™ 2.0 148 ™ 2.0 215 ™ 2.5 230 ™ 2.5 340 ™ 2.5

20 35

45 65 80 100 140 160 180 230 250

310 340 440 550 730

2700 4100

4600 5500 5500 5900 6400 7600 6800 7400 8300

8200 9600 8500 9950 8950

d0 mm Nm N

Table 1

SVC/BVC

TRU/PRU

SRC/BRC

Technical data


27/88

TRK/PRK/PVK

Number of Screw Tightening screws size torque

d0 Nm

8 10 12 15

16 20 21 25 (T/PRK) 25 (PVK) 30 32 36 39 40 44 48 50 56 60 63 64 80 100 125

6 6 6 6

6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 8 12 12

M4 M4 M4 M5

M4 M5 M5 M6 M5 M8 M6 M8 M10 M8 M10 M12 M10 M12 M16 M12 M16 M16 M16 M18

3 3 3 6

3 6 6 10 6 25 10 25 50 25 50 80 50 80 200 80 200 200 200 270

d0 Nm

Table 3

Preload adjustment

Flanged nutsFor fl anged nuts (types TRK and PRK for planetary rollerscrews - type PVK for recirculating roller screws), fi xingbolts must be tightened according to table 3.

Special inspcertifi cates ctailored to irequest.The followin

1 - Certifi 2 - Lead p 3 - Dimen

report 4 - Stiffne 5 - Magn 6 - Raw m

from 7 - Chem 8 - Heat t 9 - Induct 10 - Manu

list

Produinspeccertific

Product information


28/88

Delivery time

1 weekwithout end machining2 weekswith machined ends

Nuts

g With backlash elimination by oversize rollers:

BRC.

Details page 30

Capabilities

g Machined ends: • premachined shafts for machining by

the customer • to customer drawing (see general rules) • suitable for FLRBU units. g Screw dimensions: see page 30.

Planetary roller screws with bearing units

Service Range

Delivery time

4 weekswith machined ento customer draw

Nuts

g With axial play: SRC-S g

With backlash elimina g Preloaded: PRU-PRK

Details page 32

Capabilities

g Machined ends to cus(see general rules).

g Screw dimensions: • up to 1500 mm • up to 900 mm th

Product information


29/88

Delivery time

1 weekwithout end machining2 weekswith machined ends

Nuts

g With backlash elimination by oversize rollers:

BVC.

Details page 31

Capabilities

g Machined ends: • premachined shafts for machining by

the customer • to customer drawing (see general rules) • suitable for FLRBU units g Screw dimensions: see page 31

Recirculating roller screws with b

Service

Delivery time

4 weekswith machined endsto customer drawing

Nuts

g With axial play: SVC

g

Preloaded: PVU-PVK for

Details page 32

Capabilities

g Machined ends to custom(see general rules)

g Screw dimensions: • up to 1500 mm ma • up to 900 mm thre

Product information


30/88

Service RangePlanetary roller screws “BRC”+ thrust bearing assembly (option)

B8

Designation Ca C

oaT

pr*

R

nrd

1 d

8 d

10 B

5 B

6 R D A w

kN kN Nm N/µm

25.9

50.5

91.9

129.2

43.5

81.9

178.3

268.9

0.10

0.30

0.60

1.10

150

200

300

400

15.4

21.4

30.4

39.4

14.3

20.3

29.3

38.3

25

40

50

70

115

178

213

259

400

570

800

1046

1.2

1.2

2.0

2.0

35

45

64

80

50

64

85

100

0.5

0.5

0.5

1.0

BRC 15x5-R5

BRC 21x5-R5

BRC 30x5-R5

BRC 39x5-R5

Thrust bearingFLRBU*

b"

" "

"BB

D g6

H

0,8

0,80 8

0,81,6

R

12

d1d8

1 x 45° w x 45° w x 45°

d10

Key a

Wi

Q LWiper

Product information


31/88

Service RangeRecirculating roller screws “BVC”+ thrust bearing assembly (option)

B8

Designation Ca C

oaT

pr*

R

nrd

1 d

8 d

10 B

5 B

6 R D A w

kN kN Nm N/µm

18.5

32.9

64.3

36.6

68.4

159.2

0.20

0.30

0.40

200

250

300

20

25

32

19.1 24.1

31.1

28

33

40

116

159

179

400

500

500

1.2

1.2

1.2

34

42

54

37

44

57

0.5

0.5

1.0

BVC 20x1-R1

BVC 25x1-R1

BVC 32x1-R1

Thrust bearingFLRBU*

b"

" "

"

D g6

H

0,80,8

0,8

R

12

d145°

d8

B A h12

0,5 x 45° w x 45° w x 45°

d10

Key a

No wip

Q LubrNo wiper

Product information


32/88

Service Range Standard nuts - Planetary r

d

0

Ph

N Ca

Coa SRC/SRF TRU/PRU - TRK/PRK SRC/SRF

15

21 21 21 21

25

25

30 30

39 39

48 48

5

5 6 8 10

5

10

5 10

5 10

5 10

5

5 5 5 5

5

5

5 5

5 5

5 5

25,9

50,5 52,7 54,4 59,2

63,2

72,6

91,9 106,3

129,2 152,6

198,0 231,5

14,3

27,8 29,0 30,0 32,6

34,8

40,0

50,6 58,5

71,1 84,0

109,1 127,5

43,5

81,9 82,0 78,0 83,0

108,2

105,3

178,3 174,3

268,9 270,9

481,5 475,1

Standard nuts - Recirculating roller screws

d0 Ph N Ca Coa

SVC PVU-PVK SVC

Product information


33/88

In standard version, the “FLRBU” thrust bearing unit is assepage 30 or 31. If you require a different assembly, please inGreased for life with SKF LGEP2.

Service Range Flanged thrust bearing units

D4 D2 D5 D3 D1

L1

L2L3

1,6 E

5xS1

45°

Ø 0,2

1,6

L4L5

Angular contact ball bearing (40°) Lock nut

Basic load rating Number Bearing Maximum Axial Tilt High precision KMT nut

(axial) of designation preload rigidity rigidity bearings torque *

Flanged Ca Coa Designation Hook Tightbearing spanner torquunit kN kN Nm N/µm Nm/mrad Nm designation

27.9

40.1

74.2

109.4

208.8

31.9

63.8

119.2

188.4

392.3

2

4

4

4

4

FLRBU2

FLRBU3

FLRBU4

FLRBU5

FLRBU6

7303 BEGBP

7204 BEGBP

7305 BEGBP

7307 BEGBP

7310 BEGBP

0.25

0.25

1.10

1.10

1.50

190

400

450

600

750

51

140

160

715

1000

KMT 3

KMT 4

KMT 5

KMT 7

KMT 10

HN 4

HN 5

HN 5

HN 7

HN 10

15

18

25

42

70

Nota: other sizes available: see page 58-60.

Dimensions (mm)

L1 L2 L3 L4 D1 D2 D3 D4 D5 S1

h7 H13

Flangedbearingunit

Product information


34/88

b1 b

a

b2

d5d4

B1B2

B4

G1

45°

ba x d7cx45°

G

Rb QE R

cx45°

Dimensions (mm)

d4 d5 d9 B1 B2 B4 B3 G G1 c ba d7 Ra R

h6 h7 js12 js12 6g h11

17

20

25

35

50

15

17

20

30

40

23

27

34

45

62

66

97

112

134

168

30

40

45

55

65

96

137

157

189

233

5

7

7

10

12

FLRBU2

FLRBU3

FLRBU4

FLRBU5

FLRBU6

Thrustbearingunits

22

22

25

26

31

0.5

0.5

0.5

1

1

1.5

1.5

2.3

2.3

2.3

15.5

18.5

22.8

32.8

47.8

0.6

0.6

0.6

0.6

0.8

0

0

0

0

0

M17 ™ 1

M20 ™ 1

M25 ™ 1.5

M35 ™ 1.5

M50 ™ 1.5

Undercut l2 is defi ned p20.d9 can be equal to the root diameter for some sizes.


35/88

Planetary roller screws:technical data and dimensions

Cylindrical nuts with axial play, SRC .........................................Flanged nuts with axial play, SRF ..............................................Preloaded cylindrical nuts, TRU/PRU ........................................

Preloaded flanged nuts, TRK/PRK..............................................

Recirculating roller screws: technicadimensions Cylindrical nuts with axial play, SVC ...........................................Flanged nuts with axial play, SVF ..............................................

Preloaded cylindrical nuts, PVU .................................................Preloaded flanged nuts, PVK ......................................................

Flanged thrust bearing unit, FLRBU

Standard Range: contents

Product information


36/88

Standard Range

The full range of “SR” planetary roller screw

8

4

5

6

8

9

10

12

15

16

18

20

24

25

30

35

36

40

12

15

20

21

24

25

30

36

39

44

48

56

60

64

75

80

99

100

12

42

L e a d ,

P

Nominal diameter, d

h

o

4 5 5 6 5 6 5 5 6 5 6 5 6 5 6 5 6 5 6 6

Product information


37/88

SKF planetary roller screws

The robust screw for loin tough conditions has tadvantages n Very high load carrying capacity

n Very long lifen High rotational speed and long le

speed up to 90 metres/minuten Planetary timing mechanism perm

leration (> 12 000 rad/sec2)

n Robust design to withstand shockn Choice of 3 classes of lead precisin Planetary timing mechanism ensu

functioning even in adverse enviras ice, dirt or poor lubrication

n Special and left hand leads easily n Special steels availablen Special surface treatments and lu

availablen Nut removal without losing rollingn

Cylindrical and fl anged nuts, with pn Built in wipers available in all case

L Backlash elimination with oversias an option under following conditio

Product information


38/88

Cylindrical nuts with axial play, SRCBacklash elimination with oversize rollers L as an optio

d0 8 g 36 mm

Standard Threaded rollers Customised

L

L

LL

L

LLLL

LL

d0 Ph N ltp a Nr Nmax Ca Coa Sap mn ms Is Inn

mm mm — mm ° kN kN mm kg kg/m kgmm2/m kgmm

4

5

58

6

568

10

612

8

12

1515

20

21212121

2424

4

5

55

6

5555

66

500

750

975975

1300

1400140014001400

16001600

9,04

7,55

6,069,71

5,45

4,335,206,958,62

4,559,04

7

9

99

11

9999

1111

8

11

1110

14

11111110

1413

11,24

17,73

25,9527,43

26,83

50,5552,7754,4459,24

42,3047,65

19,59

26,71

43,5940,78

44,86

81,9782,1878,0683,01

65,1762,34

0,02

0,02

0,020,02

0,02

0,020,020,020,04

0,020,04

0,1

0,2

0,20,2

0,3

0,40,40,40,4

0,50,5

0,4

0,9

1,41,4

2,3

2,72,72,72,7

3,63,6

3,2

16,0

39,039,0

123,3

149,9149,9149,9149,9

255,7255,7

11,4

22,9

45,245,2

71,8

141,2141,2141,2141,2

173,2173,2

Product information


39/88

A

b" "

" "

BB

d1 D3

15°

D2 D

Qw x 45° w x 45°

Hd0 d2

0,8

0,8 0,8

Wiper on request

d0 d1 d2 D A w a b H Q

Designation g6/H7 h12 h9

mm mm mm mm mm mm mm mm mm m

8,4

12,4

15,415,5

20,4

21,421,421,521,8

24,424,8

8

12

1515

20

21212121

2424

SRC 8x4

SRC 12x5

SRC 15x5SRC 15x8

SRC 20x6

SRC 21x5SRC 21x6SRC 21x8SRC 21x10

SRC 24x6SRC 24x12

7,3

11,3

14,314,0

19,3

20,320,320,019,7

23,322,7

25

30

3535

40

45454545

4848

44

44

5050

50

64646464

5858

0,5

0,5

0,50,5

0,5

0,50,50,50,5

0,50,5

4

4

44

4

5555

55

12

12

1616

16

20202020

2020

26,5

31,5

36,536,5

41,5

47,047,047,047,0

50,050,0

5

5

55

5

5555

55

Wiper recess

Product information


40/88

Cylindrical nuts with axial play, SRCBacklash elimination with oversize rollers L as an optio

d0 39 g 64 mm



LLLLL

LLLL

L

LL

LLL

510152025

8121824

30

58

101520

3939393939

44444444

44

4848484848

55555

6666

6

55555

26502650265026502650

3000300030003000

3000

33003300330033003300

2,344,676,989,27

11,53

3,304,96

7,42 9,85

12,24

1,903,033,795,687,55

99999

11111111

11

99999

1211111010

14141313

12

1211111111

129,21152,62167,64172,82174,79

130,48143,71157,74167,81

165,86

198,08218,43231,54257,75265,69

268,92270,93272,89260,89249,00

261,47262,87264,94266,95

246,44

481,53470,61475,11486,36462,27

0,020,040,070,070,07

0,040,040,070,07

0,07

0,020,040,040,070,07

2,12,12,12,12,1

1,71,7

1,7 1,7

1,7

4,24,24,24,24,2

9,49,49,49,49,4

11,911,911,911,9

11,9

14,214,214,214,214,2

178E1178E1178E1178E1178E1

289E1289E1289E1289E1

289E1

409E1409E1409E1409E1409E1

203E1203E1203E1203E1203E1

173E1173E1173E1173E1

173E1

652E1652E1652E1652E1652E1


Product information


41/88

A

b" "

" "

BB

d1 D3

15°

D2 D

Qw x 45° w x 45°

Hd0 d2

0,8

0,8 0,8

Wiper on requestWiper recess




39,439,840,240,540,9

44,444,845,245,5

45,9

48,448,648,849,249,5

3939393939

44444444

44

4848484848

SRC 39x5SRC 39x10SRC 39x15SRC 39x20SRC 39x25


SRC 44x30

SRC 48x5SRC 48x8SRC 48x10SRC 48x15SRC 48x20

38,337,737,136,535,9

43,242,742,141,5

40,9

47,347,146,746,145,5

8080808080

80808080

80

100100100100100

100100100100100

90909090

90

127127127127127

1,01,01,01,01,0

0,50,50,50,5

0,5

1,01,01,01,01,0

88888

6666

6

88888

4040404040

32323232

32

4545454545

83,083,083,083,083,0

82,582,582,582,5

82,5

103,0103,0103,0103,0103,0

7,07,07,07,07,0

7,07,07,07,0

7,0

7,07,07,07,07,0

Product information


42/88

Cylindrical nuts with axial play, SRCd0 75 g 210 mm


mm mm — mm ° kN kN mm kg kg/m kgmm2/m kgmm2

10

1520

12182436

75

7575

80808080

5

55

6666

5500

55005500

6000600060006000

2,43

3,644,85

2,734,105,458 15

11

1111

13131311

12

1111

14141413

504,86

561,29572,26

410,27455,94485,80442 89

1486,68

1491,301495,87

1163,161167,631172,06999 09

0,04

0,070,07

0,040,070,070 07

14,6

14,614,6

8,98,98,98 9

34,7

34,734,7

39,539,539,539 5

244E2

244E2244E2

316E2316E2316E2316E2

469E2

469E2469E2

260E2260E2260E2252E2


Product information


43/88




75,8

76,276,5

80,881,281,582 3

75

7575

80808080

SRC 75x10

SRC 75x15SRC 75x20


73,7

73,172,5

78,778,177,576 3

150

150150

140140140140

191

191191

156156156156

1,0

1,01,0

1,01,01,01 0

10

1010

10101010

63

6363

63636363

153

153153

143143143143

10

1010

10101010

A

b" "

" "

BB

d1 D3

15°

D2 D

Qw x 45° w x 45°

Hd0 d2

0,8

0,8 0,8


Product information


44/88

Flanged nuts with axial play, SRFBacklash elimination with oversize rollers L as an optio

d0 8 g 36 mm




4

5

58

6

568

10

612

8

12

1515

20

21212121

2424

4

5

55

6

5555

66

500

750

975975

1300

1400140014001400

16001600

9,04

7,55

6,069,71

5,45

4,335,206,95

8,62

4,55 9,04

7

9

99

11

9999

1111

8

11

1110

14

11111110

1413

11,24

17,73

25,9527,43

26,83

50,5552,7754,4459,24

42,3047,65

19,59

26,71

43,5940,78

44,86

81,9782,1878,0683,01

65,1762,34

0,02

0,02

0,020,02

0,02

0,020,020,020,04

0,020,04

0,3

0,3

0,50,5

0,5

0,70,70,70,7

0,80,8

0,4

0,9

1,41,4

2,3

2,72,72,72,7

3,63,6

3,2

16,0

39,039,0

123,3

149,9149,9149,9149,9

255,7255,7

66,4

106,0

201,6201,6

289,5

436,6436,6436,6436,6

524,2524,2

L

L

LL

L

LLLL

LL

Product information


45/88

A

r r

A2

A1

d1 D3 D2

G

Dg6/H7

D1d0 d2

0,8

0,8

D0 +0,5

d0 d1 d2 D A A1 A2 D1 J G r Q

Designation h12 js12 +0,4

mm mm mm mm mm mm mm mm mm mm mm mm

8,4

12,4

15,415,5

20,4

21,421,421,521,8

24,424,8

8

12

1515

20

21212121

2424

SRF 8x4

SRF 12x5

SRF 15x5SRF 15x8

SRF 20x6

SRF 21x5SRF 21x6SRF 21x8SRF 21x10

SRF 24x6SRF 24x12

7,3

11,3

14,314,0

19,3

20,320,320,019,7

23,322,7

25

30

3535

40

45454545

4848

44

44

5050

50

64646464

5858

14,0

14,0

16,016,0

16,0

23,023,023,023,0

20,020,0

16

16

1818

18

18181818

1818

46

51

5858

63

68686868

7171

36

41

4646

51

56565656

5959

6xM4

6xM4

6xM56xM5

6xM5

6xM56xM56xM56xM5

6xM56xM5

0,4

0,4

0,40,4

0,8

0,80,80,80,8

0,80,8

M6

M6

M6M6

M6

M6M6M6M6

M6M6

Wiper on request

Wiper recess

Equidistant

Product information


46/88

510152025

8121824

30

58

101520

3939393939

44444444

44

4848484848

55555

6666

6

55555

26502650265026502650

3000300030003000

3000

33003300330033003300

2,34 4,67 6,98 9,2711,53

3,304,96

7,42 9,85

12,24

1,903,03

3,79 5,687,55

99999

11111111

11

99999

1211111010

14141313

12

1211111111

129,21152,62167,64172,82174,79

130,48143,71157,74167,81

165,86

198,08218,43231,54257,75265,69

268,92270,93272,89260,89249,00

261,47262,87264,94266,95

246,44

481,53470,61475,11486,36462,27

0,020,040,070,070,07

0,040,040,070,07

0,07

0,020,040,040,070,07

4,04,04,04,04,0

3,63,6

3,6 3,6

3,6

7,8 7,87,87,87,8

9,49,49,49,49,4

11,911,911,911,9

11,9

14,214,214,214,214,2

178E1178E1178E1178E1178E1

289E1289E1289E1289E1

289E1

409E1409E1409E1409E1409E1

836E1836E1836E1836E1836E1

803E1803E1803E1803E1

803E1

185E2185E2185E2185E2185E2

LLLLL

LLLL

L

LL

LLL

Flanged nuts with axial play, SRFBacklash elimination with oversize rollers L as an optio

d0 39 g 64 mm




Product information


47/88

39,439,840,240,540,9

44,444,845,245,5

45,9

48,448,648,849,249,5

3939393939

44444444

44

4848484848

SRF 39x5SRF 39x10SRF 39x15SRF 39x20SRF 39x25


SRF 44x30

SRF 48x5SRF 48x8SRF 48x10SRF 48x15SRF 48x20

38,337,737,136,535,9

43,242,742,141,5

40,9

47,347,146,746,145,5

8282828282

82828282

82

105105105105105

100100100100100

90909090

90

127127127127127

33,533,533,533,533,5

28,528,528,528,5

28,5

45,045,045,045,045,0

3333333333

33333333

33

3737373737

124124124124124

124124124124

124

150150150150150

102102102102102

102102102102

102

127127127127127

6xM106xM106xM106xM106xM10

6xM106xM106xM106xM10

6xM10


1,21,21,21,21,2

1,21,21,21,2

1,2

1,21,21,21,21,2

M6M6M6M6M6

M6M6M6M6

M6

M8x1M8x1M8x1M8x1M8x1

A

r r

A2

A1

d1 D3 D2

G

Dg6/H7

D1d0 d2

0,8

0,8

D0 +0,5




Wiper on request

Wiper recess

Equidistant

Product information

Fl d t ith i l l SRF


48/88

Flanged nuts with axial play, SRFd0 75 g 210 mm



10

1520

12182436

75

7575

80808080

5

55

6666

5500

55005500

6000600060006000

2,43

3,64 4,85

2,73 4,10 5,458 15

11

1111

13131311

12

1111

14141413

504,86

561,29572,26

410,27455,94485,80442 89

1486,68

1491,301495,87

1163,161167,631172,06999 09

0,04

0,070,07

0,040,070,070 07

20,6

20,620,6

17,717,717,717 7

34,7

34,734,7

39,539,539,539 5

244E2

244E2244E2

316E2316E2316E2316E2

114E3

114E3114E3

108E3108E3108E3108E3


Product information


49/88




75,8

76,276,5

80,881,281,582 3

75

7575

80808080

SRF 75x10

SRF 75x15SRF 75x20


73,7

73,172,5

78,778,177,576 3

150

150150

150150150150

191

191191

156156156156

73,0

73,073,0

55,555,555,555 5

45

4545

45454545

210

210210

210210210210

180

180180

180180180180

8xM16

8xM168xM16

8xM168xM168xM168xM16

1,6

1,61,6

1,61,61,61 6

M8x1

M8x1M8x1

M8x1M8x1M8x1M8x1

A

r r

A2

A1

d1 D3 D2

G

Dg6/H7

D1d0 d2

0,8

0,8

D0 +0,5

Wiper on request

Wiper recess

Equidistant

Product information

Preloaded cylindrical nuts TRU for backlash eliminatio


50/88

Preloaded cylindrical nuts, TRU for backlash eliminatio PRU for optimum rigidity

d0 8 g 36 mm

TRU PRU

d0 Ph N ltp a Nr Nmax Ca Coa Tpe Rng Rnr Tpr Fpr mn ms

mm mm — mm ° kN kN Nm N/µm N/µm Nm N kg kg/m


4

5

58

6

568

10

612

8

12

1515

20

21212121

2424

4

5

55

6

5555

66

400

600

750750

1050

1100110011001100

12501250

9,04

7,55

6,069,71

5,45

4,335,206,95

8,62

4,55 9,04

7

9

99

11

9999

1111

8

11

1110

14

11111110

1413

6,19

9,77

14,3015,11

14,78

27,8529,0830,0032,64

23,3126,25

9,79

13,36

21,8020,39

22,43

40,9841,0939,0341,51

32,5931,17

0,07

0,13

0,190,19

0,30

0,330,330,330,33

0,410,41

110

180

290242

290

400359311200

370150

150

240

380315

380

520467404260

490200

0,06 - 0,13

0,12 - 0,25

0,18 - 0,360,18 - 0,36

0,26 - 0,58

0,31 - 0,630,31 - 0,630,31 - 0,630,31 - 0,63

0,39 - 0,780,39 - 0,78

236

570

932954

1305

134113941354 557

1597 541

0,1

0,2

0,20,2

0,3

0,40,40,40,4

0,50,5

0,4

0,9

1,41,4

2,3

2,72,72,72,7

3,63,6

Product information


51/88

A

b" "

" "

BB

d1 D3

15°

D2 D

Qw x 45° w x 45°

Hd0 d2

0,8

0,8 0,8




8,4

12,4

15,415,5

20,4

21,421,421,521,8

24,424,8

8

12

1515

20

21212121

2424

TRU/PRU 8x4

TRU/PRU 12x5

TRU/PRU 15x5TRU/PRU 15x8

TRU/PRU 20x6

TRU/PRU 21x5TRU/PRU 21x6TRU/PRU 21x8TRU/PRU 21x10

TRU/PRU 24x6TRU/PRU 24x12

7,3

11,3

14,314,0

19,3

20,320,320,019,7

23,322,7

25

30

3535

40

45454545

4848

44

44

5050

50

64646464

5858

0,5

0,5

0,50,5

0,5

0,50,50,50,5

0,50,5

4

4

44

4

5555

55

12

12

1616

16

20202020

2020

26,5

31,5

36,536,5

41,5

47,047,047,047,0

50,050,0


Product information

Preloaded cylindrical nuts TRU for backlash eliminatio


52/88

Preloaded cylindrical nuts, TRU for backlash eliminatio PRU for optimum rigidity

d0 39 g 64 mm

TRU PRU



510152025

812182430

58

101520

3939393939

4444444444

4848484848

55555

66666

55555

21002100210021002100

24002400240024002400

26002600260026002600

2,344,676,989,27

11,53

3,304,967,429,85

12,24

1,903,033,795,687,55

99999

1111111111

99999

1211111010

1414131312

1211111111

71,1984,0992,3695,2296,30

71,8979,1886,9192,4691,38

109,13120,34127,57142,01146,38

134,46135,46136,45130,45124,50

130,73131,44132,47133,48123,22

240,77235,30237,56243,18231,14

0,920,920,920,920,92

1,121,121,121,121,12

1,301,301,301,301,30

750500390220210

688610430290190

1080889760600460

980650510290280

895800550380250

14101156 980 780 600

0,88 - 1,750,88 - 1,750,88 - 1,750,88 - 1,751,31 - 2,19

1,07 - 2,141,07 - 2,141,07 - 2,141,07 - 2,141,60 - 2,68

1,24 - 2,471,24 - 2,471,24 - 2,471,24 - 2,471,24 - 2,47

228819651465 694697

243222971497 725727

26982583240520721423

2,12,12,12,12,1

1,71,7

1,7 1,7 1,7

4,24,2

4,2 4,2 4,2

9,49,49,49,49,4

11,911,911,911,911,9

14,214,214,214,214,2


Product information


53/88




39,439,840,240,540,9

44,444,845,245,545,9

48,448,648,849,249,5

3939393939

4444444444

4848484848

TRU/PRU 39x5TRU/PRU 39x10TRU/PRU 39x15TRU/PRU 39x20TRU/PRU 39x25



38,337,737,136,535,9

43,242,742,141,540,9

47,347,146,746,145,5

8080808080

8080808080

100100100100100

100100100100100

9090909090

127127127127127

1,01,01,01,01,0

0,50,50,50,50,5

1,01,01,01,01,0

88888

66666

88888

4040404040

3232323232

4545454545

83,083,083,083,083,0

82,582,582,582,582,5

103,0103,0103,0103,0103,0

77777

77777

77777

A

b" "

" "

BB

d1 D3

15°

D2 D

Qw x 45° w x 45°

Hd0 d2

0,8

0,8 0,8


Product information

Preloaded flanged nuts, TRK for backlash elimination


54/88

Preloaded flanged nuts, TRK for backlash elimination PRK for optimum rigidity

d0 8 g

36 mm

TRK PRK




4

5

58

6

568

10

612

8

12

1515

20

21212121

2424

4

5

55

6

5555

66

400

600

750750

1050

1100110011001100

12501250

9,04

7,55

6,069,71

5,45

4,335,206,95

8,62

4,55 9,04

7

9

99

11

9999

1111

8

11

1110

14

11111110

1413

6,19

9,77

14,3015,11

14,78

27,8529,0830,0032,64

23,3126,25

9,79

13,36

21,8020,39

22,43

40,9841,0939,0341,51

32,5931,17

0,07

0,13

0,190,19

0,30

0,330,330,330,33

0,410,41

110

180

290242

290

400359311200

370150

150

240

380315

380

520467404260

490200

0,06 - 0,13

0,12 - 0,25

0,18 - 0,360,18 - 0,36

0,26 - 0,58

0,31 - 0,630,31 - 0,630,31 - 0,630,31 - 0,63

0,39 - 0,780,39 - 0,78

236

570

932954

1305

134113941354 557

1597 541

0,3

0,3

0,50,5

0,5

0,70,70,70,7

0,80,8

0,4

0,9

1,41,4

2,3

2,72,72,72,7

3,63,6

Product information


55/88

A

r r

A2

A1

BB

d1 D3

15°

D2

G

Dg6/H7

D1d0 d2 D0

+0,5

0,8

0,8

Wiper recess

Wiper on request

Dowel pins

to hold preload




8,4

12,4

15,415,5

20,4

21,421,021,021,8

24,424,8

8

12

1515

20

21212121

2424

TRK/PRK 8x4

TRK/PRK 12x5

TRK/PRK 15x5TRK/PRK 15x8

TRK/PRK 20x6

TRK/PRK 21x5TRK/PRK 21x6TRK/PRK 21x8TRK/PRK 21x10

TRK/PRK 24x6TRK/PRK 24x12

7,3

11,3

14,314,0

19,3

20,320,320,019,7

23,322,7

25

30

3535

40

45454545

4848

44

44

5050

50

64646464

5858

14,0

14,0

16,016,0

16,0

23,023,023,023,0

20,020,0

16

16

1818

18

18181818

1818

46

51

5858

63

68686868

7171

36

41

4646

51

56565656

5959

6xM4

6xM4

6xM56xM5

6xM5

6xM56xM56xM56xM5

6xM56xM5

0,4

0,4

0,40,4

0,8

0,80,80,80,8

0,80,8

M6

M6

M6M6

M6

M6M6M6M6

M6M6

Equidistant

Product information

Preloaded flanged nuts, TRK for backlash elimination


56/88

g PRK for optimum rigidity

d0 39 g

64 mm

TRK PRK



510152025

812182430

58

101520

3939393939

4444444444

4848484848

55555

66666

55555

21002100210021002100

24002400240024002400

26002600260026002600

2,34 4,67 6,98 9,2711,53

3,304,96

7,42 9,8512,24

1,903,03

3,79 5,68 7,55

99999

1111111111

99999

1211111010

1414131312

1211111111

71,1984,0992,3695,2296,30

71,8979,1886,9192,4691,38

109,13120,34127,57142,01146,38

134,46135,46136,45130,45124,50

130,73131,44132,47133,48123,22

240,77235,30237,56243,18231,14

0,920,920,920,920,92

1,121,121,121,121,12

1,301,301,301,301,30

750500390220210

761610

430 290 190

1080889

760 600 460

980650510290280

989800

550 380 250

14101156 980 780 600

0,88 - 1,750,88 - 1,750,88 - 1,750,88 - 1,751,31 - 2,19

1,07 - 2,141,07 - 2,141,07 - 2,141,07 - 2,141,60 - 2,68

1,24 - 2,471,24 - 2,471,24 - 2,471,24 - 2,471,24 - 2,47

228819651465 694 697

344522971497 725 724

26982583240520721423

4,04,04,04,04,0

3,63,6

3,6 3,6 3,6

7,77,7

7,7 7,7 7,7

9,49,49,49,49,4

11,911,911,911,911,9

14,214,214,214,214,2


Product information


57/88



mm mm mm mm mm mm mm mm mm mm mm m

39,439,840,240,540,9

44,444,845,245,545,9

48,448,648,849,249,5

3939393939

4444444444

4848484848

TRK/PRK 39x5TRK/PRK 39x10TRK/PRK 39x15TRK/PRK 39x20TRK/PRK 39x25



38,337,737,136,535,9

43,242,742,141,540,9

47,347,146,746,145,5

8282828282

8282828282

105105105105105

100100100100100

9090909090

127127127127127

33,533,533,533,533,5

28,528,528,528,528,5

4545454545

3333333333

3333333333

3737373737

124124124124124

124124124124124

150150150150150

102102102102102

102102102102102

127127127127127




1,21,21,21,21,2

1,21,21,21,21,2

1,21,21,21,21,2

MMMMM

MMMMM

M8xM8xM8xM8xM8x

A

r r

A2 A1

BB

d1 D3

15°

D2

G

Dg6/H7

D1d0 d2 D0

+0,5

0,8

0,8

Wiper recess

Wiper on request

Dowel pins

to hold preload

Equidistant

Product information

Flanged thrust bearing units


58/88

In standard version, the “FLRBU” thrust bearing unit is aspage 30 or 31. If you require a different assembly, pleaseGreased for life with SKF LGEP2.

g g

Angular contact ball bearing (40°) Lock nut

Basic load rating Number Bearings Maximum Axial Tilt High precision KMT nut (axial) of designation preload rigidity rigidity

bearings torque *

Flanged Ca Coa Designation Hook Tbearing spanner tunit kN kN Nm N/µm Nm/mrad Ndesignation

13,3

27.9

40.1 74.2

109.4

208.8

305,3

473,1

14,7

31.9

63.8 119.2

188.4

392.3

615,4

1123

2

2

4 4

4

4

4

4

FLRBU1

FLRBU2

FLRBU3FLRBU4

FLRBU5

FLRBU6

FLRBU7

FLRBU8

7201 BEGBP

7303 BEGBP

7204 BEGBP 7305 BEGBP

7307 BEGBP

7310 BEGBP

7313 BEGBP 7318 BEGBP

0.10

0.25

0.25 1.10

1.10

1.50

2.00

2.30

150

190

400 450

600

750

1250

1500

40

51

140 160

715

1000

3200

7500

KMT 1

KMT 3

KMT 4 KMT 5

KMT 7

KMT 10

KMT 13

KMT 18

HN 3

HN 4

HN 5 HN 5

HN 7

HN 10

HN 14

HN 18

D4 D2 D5 D3 D1

L1

L2L3

1,6

E

45

Ø 0,2

1,6

L4L5

Dimensions (mm)

L1 L2 L3 L4 D1 D2 D3 D4 D5

h7

Flangedbearingunit

Product information


59/88

Dimensions (mm)

d4 d5 d9 B1 B2 B4 B3 G G1 c ba d7 Ra Rb

h6 h7 js12 js12 6g h11

12

17

20

25 35

50

65

90

10

15

17

20 30

40

60

85

17

23

27

34 45

62

78

108

58

66

97

112 134

168

210

270

20

30

40

45 55

65

100

120

78

96

137

157 189

233

310

390

5

5

7

7 10

12

18

25

FLRBU1

FLRBU2

FLRBU3

FLRBU4FLRBU5

FLRBU6

FLRBU7

FLRBU8

Thrustbearingunits

17

22

22

25 26

31

32

39

0.5

0.5

0.5

0.5 1

1

1

1

1.5

1.5

1.5

2.3 2.3

2.3

3.0

3.0

10.5

15.5

18.5

22.8 32.8

47.8

62.2

87.2

0.4

0.6

0.6

0.6 0.6

0.8

1.2

1.6

0.4

0.6

0.6

0.6 0.6

0.8

1.0

1.2

M12 ™ 1

M17 ™ 1

M20 ™ 1

M25 ™ 1.5 M35 ™ 1.5

M50 ™ 1.5

M65 ™ 2

M90 ™ 2

Undercut l2 is defi ned p20.d9 can be equal to the root diameter for some sizes.

b1b

a

b2

d5d4

B1B2

B4

G1

45°

ba x d7cx45°

G

Rb QE Ra

cx45°

Product information

Other possible bearing arrangement


60/88

In case of load acting mainly in one direction, we recommend following thrust bear

Ca (kN) Coa (kN) Ca (kN)

FLRBU1 (*): No other possible arrangement (1+1)FLRBU2 (*): No other possible arrangement (1+1)

FLRBU3

FLRBU4

FLRBU5

FLRBU6

FLRBU7

FLRBU8

53,3

98,6

145,3

277,3

405,5

628,3

--

95,7

178,8

282,6

588,6

923,1

1684,6

--

24,7

45,7

67,3

128,5

187,9

291,2

Product information

Flanged thrust bearing units


61/88

Flange Suitable for SRC & SRF Suitable for PRU & PRKthrust bearing

SKF “FLRBU” fl anged thrust bearing units can be fi tted on the screw shafts in the tab

FLRBU1

FLRBU2

FLRBU3

FLRBU4

FLRBU5

FLRBU6

FLRBU7

SR 8 ™ 4 - R4

SR 12 ™ 5 - R5SR 15 ™ 5 - R5 — SR 15 ™ 8 - R5SR 20 ™ 6 - R6

SR 24 ™ 6 - R6

SR 21 ™ 5 - R5 — SR 21 ™ 6 - R5 — SR 21 ™ 8 - R5SR 21 ™ 10 - R5SR 24 ™ 12 - R6SR 25 ™ 5 - R5 — SR 25 ™ 10 - R5 — SR 25 ™ 15 - R5

SR 30 ™ 5 - R5 — SR 30 ™ 6 - R5 — SR 30 ™ 10 - R5

SR 30 ™ 20 - R5SR 36 ™ 6 - R6 — SR 36 ™ 9 - R6 — SR 36 ™ 12 - R6SR 36 ™ 18 - R6 — SR 36 ™ 24 - R6

SR 39 ™ 5 - R5 — SR 39 ™ 10 - R5 — SR 39 ™ 15 - R5SR 39 ™ 20 - R5 — SR 39 ™ 25 - R5SR 44 ™ 8 - R6 — SR 44 ™ 12 - R6 — SR 44 ™ 18 - R6SR 44 ™ 24 - R6 — SR 44 ™ 30 - R6

SR 48 ™ 5 - R5 — SR 48 ™ 8 - R5 — SR 48 ™ 10 - R5SR 56 ™ 12 - R6

SR 48 ™ 15 - R5 — SR 48 ™ 20 - R5 — SR 48 ™ 25 - R5SR 56 ™ 24 - R6 — SR 56 ™ 36 - R6SR 64 12 R6 SR 64 18 R6 SR 64 24 R6

PR 8 ™ 4 - R4PR 12 ™ 5 - R5PR 15 ™ 5 - R5 — PR 15 ™ 8 -

PR 20 ™ 6 - R6PR 21 ™ 5 - R5 — PR 21 ™ 6 -PR 24 ™ 6 - R6 — PR 24 ™ 12

PR 21 ™ 10 - R5PR 25 ™ 5 - R5 — PR 25 ™ 10

PR 30 ™ 5 - R5 — PR 30 ™ 6 -PR 30 ™ 20 - R5PR 36 ™ 6 - R6 — PR 36 ™ 9 -PR 36 ™ 18 - R6 — PR 36 ™ 24 PR 39 ™ 5 - R5PR 44 ™ 8 - R6 — PR 44 ™ 12

PR 39 ™ 10 - R5 — PR 39 ™ 15

PR 39 ™ 25 - R5PR 44 ™ 18 - R6 — PR 44 ™ 24 PR 48 ™ 5 - R5 — PR 48 ™ 8 -PR 56 ™ 12 - R6

PR 48 ™ 10 - R5 — PR 48 ™ 15 PR 48 ™ 25 - R5PR 56 ™ 24 - R6 — PR 56 ™ 36 PR 60 ™ 10 - R5 — PR 60 ™ 15

PR 64 ™ 12 - R6 — PR 64 ™ 18 PR 64 ™ 30 - R6 — PR 64 ™ 36

Product information

Standard Range


62/88

The full range of “SV” recirculating roller scr

1

2

3

4

5

L e a d ,

P h

External diameter, d 1

8 10 12 16 20 25 32 40 50 63

Standard program

Right hand lead

Manufacturing possibilities

on request

Product information

SKF recirculating roller screws


63/88

The fine screw for ultimtioning accuracy has theadvantages

n 1 mm lead on screws from8 - 50 mm diameter

n Fine resolutionn Choice of 3 classes of lead precisin Minimum input torque because o

mechanical advantagen Simplifi cation of transmissions to

performancen High load capacityn Long life

n High rigidity and reliability (no miparts)

n Special surface treatments and luavailable

n Cylindrical nuts with play or prelon

Flanged nuts with play or preload

L Backlash elimination with oversias an option under following conditio

Product information

Cylindrical nuts with axial play, SVCNuts with or without wiper recesses (standard = withou


64/88

Nuts with or without wiper recesses (standard = withouBacklash elimination with oversize rollers L as an optio

d1 Ph N ltp a Ca Coa Sap mn ms Is Inn


L

L

LLL

LL

LL

LL

LL

L

Standard Grooved rollers Customised

1

1

2

12

12

12

12

12

1

8

10

10

12 12

16 16

20 20

25 25

32 32

40

1

1

212

12

12

12

12

1

500

650

650750

750

10501050

13001300

16501650

21502150

2700

2,28

1,82

3,641,523,04

1,142,28

0,911,82

0,731,46

0,571,14

0 46

8,4

8,9

8,910,3

10,3

11,5 11,5

18,5 18,5

32,9 32,9

64,3 64,3

79 1

11,0

11,4

11,414,0

14,0

16,8 16,8

36,6 36,6

68,4 68,4

159,2 159,2

231 6

0,02

0,02

0,020,020,02

0,020,02

0,020,02

0,020,02

0,020,02

0 02

0,1

0,1

0,10,1

0,1

0,1 0,1

0,2 0,2

0,3 0,3

0,6 0,6

1 2

0,36

0,57

0,570,84

0,84

1,51 1,51

2,38 2,38

3,75 3,75

6,18 6,18

9 69

2,6

6,7

6,714,2

14,2

46,2 46,2

114,9114,9

284,5284,5

773,3773,3

190E1

3,6

5,0

5,06,7

6,7

14,0 14,0

29,8 29,8

79,3 79,3

280,2280,2

878 7

A

Product information


65/88

b" "

" "

B

d1 D2 D2-0,3

gD

Qw x 45° w x 45°

Hd0 d2

0,8

0,8 0,8

d0 d1 d2 D A B w a b

Designation g6/H7 with wiper without wiper h9

recess h12 recess h12

mm mm mm mm mm mm mm mm mm mm

8

10

101212

1616

2020

2525

3232

40

7,7

9,7

9,711,711,7

15,715,7

19,719,7

24,724,7

31,731,7

39 7

SVC 8x1

SVC 10x1

SVC 10x2SVC 12x1SVC 12x2

SVC 16x1SVC 16x2

SVC 20x1SVC 20x2

SVC 25x1SVC 25x2

SVC 32x1SVC 32x2

SVC 40x1

7,1

9,1

9,111,111,1

15,115,1

19,119,1

24,124,1

31,131,1

39 1

20

22

222424

2929

3434

4242

5454

68

40

40

404040

4040

4545

5454

6767

75

4

4

444

44

44

55

55

5

0,2

0,2

0,20,20,2

0,50,5

0,50,5

0,50,5

1,01,0

1 0

2

2

222

33

33

44

44

5

12

12

121212

1212

1616

2020

2525

32

31

31

313131

3131

3737

4444

5757

63

Wiper on request

Product information

Flanged nuts with axial play, SVFBacklash elimination with oversize rollers L as an optio


66/88

Backlash elimination with oversize rollers L as an optio

d1 Ph N ltp a Ca Coa Sap mn ms Is Inn


L

LL

LL

LL

LL

LL

LL

L

1

1

212

12

12

12

12

1

8

10

1012

12

16 16

20 20

25 25

32 32

40

1

1

212

12

12

12

12

1

500

650

650750

750

10501050

13001300

16501650

21502150

2700

2,28

1,82

3,641,523,04

1,142,28

0,911,82

0,731,46

0,571,14

0 46

8,4

8,9

8,910,3

10,3

11,5 11,5

18,5 18,5

32,9 32,9

64,3 64,3

79 1

11,0

11,4

11,414,0

14,0

16,8 16,8

36,6 36,6

68,4 68,4

159,2 159,2

231 6

0,02

0,02

0,020,020,02

0,020,02

0,020,02

0,020,02

0,020,02

0 02

0,2

0,2

0,20,2

0,2

0,3 0,3

0,4 0,4

0,6 0,6

1,2 1,2

2 1

0,36

0,57

0,570,84

0,84

1,51 1,51

2,38 2,38

3,75 3,75

6,18 6,18

9 69

2,6

6,7

6,714,2

14,2

46,2 46,2

114,9114,9

284,5284,5

773,3773,3

190E1

47,9

47,0

47,063,5

63,5

100,3100,3

191,9191,9

415,8415,8

111E1111E1

312E1

Standard Grooved rollers Customised

Product information

A


67/88

d0 d1 d2 D A A1 A2 D1 J G r


mm mm mm mm mm mm mm mm mm mm mm

8

10

101212

1616

2020

2525

3232

40

7,7

9,7

9,711,711,7

15,715,7

19,719,7

24,724,7

31,731,7

39 7

SVF 8x1

SVF 10x1

SVF 10x2SVF 12x1SVF 12x2

SVF 16x1SVF 16x2

SVF 20x1SVF 20x2

SVF 25x1SVF 25x2

SVF 32x1SVF 32x2

SVF 40x1

7,1

9,1

9,111,111,1

15,115,1

19,119,1

24,124,1

31,131,1

39 1

22

22

222525

3030

3535

4545

5656

68

40

40

404040

4040

4545

5454

6767

75

12,0

12,0

12,012,012,0

12,012,0

13,513,5

18,018,0

23,523,5

24 0

16

16

161616

1616

1818

1818

2020

27

43

43

434646

5151

5858

6868

Documents

Standard SKF