Roller screws - SKF

1 Roller screws SKF is a registered trademark of the SKF Group. SKF Group 2014 The contents of this publication are the copyright of the publisher and may not be reproduced (even extracts) unless prior written permission is granted. Every care has been taken to ensure the accuracy of the information contained in this publication but no liability can be accepted for any loss or damage whether direct, indirect or consequential arising out of the use of the information contained MT/P1 14489 EN April 2014 This publication supersedes publication image(s) used under license from Selection Planetary Roller screws Ultra Power Roller screws Inverted Roller screws Rotating nut with planetary Roller screws Recirculating Roller screws Support bearings FLRBUC Calculation formulae and exampleD Recommendations for assemblyE Additional informationContentsA Product informationSKF the knowledge engineering company.

2 4 Selection guide .. 6 Planetary Roller screws SR/BR, HR .. 6 Planetary Roller screws PR, with internal preload .. 8 Inverted Roller screws ISR/IBR .. 10 Rotating nut Roller screws SRR/BRR .. 10 Recirculating Roller screws SV/BV .. 11 Recirculating Roller screws PV, with internal preload .. 11 Preferred range .. 12 Introduction to Roller screws .. 14 SKF Roller screws , high performance driving solutions .. 14 Typical applications for Roller screws .. 16 Roller screws conceptual design advantage over ball screws .. 18 Technical concepts .. 19 Introduction to SKF Roller screws .. 19 Basic dynamic load carrying capacity .. 19 Nominal fatigue life .. 19 Service life .. 20 Equivalent dynamic load .. 20 Basic static load carrying capacity .. 20 Critical rotating speed for screw shafts .. 21 Permissible speed limit and acceleration.

3 21 Efficiency .. 22 Back driving and braking torque .. 23 Break away torque .. 23 Driving torque .. 23 Static axial stiffness .. 23 Materials, heat treatment and coatings .. 24 Operating temperature .. 25 screw shaft buckling or column strength .. 25 Shaft design .. 26 Product inspection and certification .. 27 Working environment .. 27 Lubrication .. 28 Lubrication for Roller screws .. 28 Grease lubrication .. 29 Oil lubrication .. 34 Wipers .. 34 Dry lubricants .. 34 Axial play and preload .. 36 Axial play and preload .. 36 Preload and stiffness .. 36 Preload torque .. 38 Preload torque tolerances .. 38 Preload adjustment .. 40 Lead precision and manufacturing tolerances .. 42 Lead precision .. 42 Manufacturing tolerances .. 46B Product dataPlanetary Roller screws SR .. 50 SRC/BRC planetary Roller screws with cylindrical nut.

4 52 SRF/BRF/SRP/BRP planetary Roller screws with flanged nut .. 58 PRU preloaded planetary Roller screws with cylindrical nut .. 64 PRK preloaded planetary Roller screws with flanged nut .. 70 Ultra Power Roller screws HR.. 74 HRC Ultra Power Roller screws with cylindrical nut .. 76 HRF/HRP Ultra Power Roller screws with flanged nut .. 80 Inverted Roller screws ISR .. 84 Rotating nut with planetary Roller screws SRR .. 88 SRR/BRR planetary Roller screws with rotating nut .. 90 Recirculating Roller screws SV .. 92 SVC/BVC recirculating Roller screws with cylindrical nut .. 94 SVF/BVF recirculating Roller screws with flanged nut .. 96 PVU preloaded recirculating Roller screws with cylindrical nut . 98 PVK preloaded recirculating Roller screws with flanged nut .. 1002 Support bearings FLRBU .. 102 FLRBU support bearings with angular contact ball bearings.

5 104 Standard machined ends .. 105 Recommendations for support bearings assembly and orientation .. 106 Support bearings recommended for standard planetary Roller screws .. 107 Support bearings recommended for recirculating Roller screws .. 108 Preselection of spherical Roller thrust bearings .. 109C Calculation formulae and exampleCalculation formulae .. 111 Calculation example .. 114D Recommendations for assemblyHandling, storage, nut disassembly, support bearing assembly, alignment .. 117 Alignment .. 120E Additional information .. 122 Technical request form .. 122 Symbols .. 124 Electro mechanical cylinders .. 126 Linear Motion solutions .. 131 Designation system .. 1323 From one simple but inspired solution to a misalignment problem in a textile mill in Sweden, and fifteen employees in 1907, SKF has grown to become a global industrial knowledge leader.

6 Over the years, we have built on our exper-tise in bearings, extending it to seals, mecha-tronics, services and lubrication systems. Our knowledge network includes 46 000 employees, 15 000 distributor partners, offices in more than 130 countries, and a growing number of SKF Solution Factory sites around the world. Research and development We have hands-on experience in over forty industries based on our employees know-ledge of real life conditions. In addition, our world-leading experts and university part-ners pioneer advanced theoretical research and development in areas including tribol-ogy, condition monitoring, asset manage-ment and bearing life theory. Our ongoing commitment to research and devel opment helps us keep our customers at the forefront of their industries. Meeting the toughest challenges Our network of knowledge and experience, along with our understanding of how our core technologies can be combined, helps us create innovative solutions that meet the toughest of challenges.

7 We work closely with our customers throughout the asset life cycle, helping them to profitably and re spon sibly grow their Solution Factory makes SKF knowledge and manu facturing expertise available locally to provide unique solutions and services to our with SKF IT and logistics systems and application experts, SKF Authorized Distributors deliver a valuable mix of product and application knowledge to customers for a sustainable future Since 2005, SKF has worked to reduce the negative environmental impact from our operations and those of our suppliers. Our continuing technology development resulted in the introduction of the SKF BeyondZero portfolio of products and services which im-prove efficiency and reduce energy losses, as well as enable new technol ogies har-nessing wind, solar and ocean power. This combined approach helps reduce the en vir-on mental impact both in our oper ations and our customers oper the knowledge engineering company44 BearingsSKF is the world leader in the design, development and manufacture of high performance rolling bearings, plain bearings, bearing units and maintenanceCondition monitoring technologies and main-tenance services from SKF can help minimize unplanned downtime, improve operational efficiency and reduce maintenance solutionsSKF offers standard seals and custom engineered sealing solutions to increase uptime, improve machine reliability, reduce friction and power losses, and extend lubricant fly-by-wire systems for aircraft and drive-by-wire systems for off-road, agricultural and forklift applications replace heavy.

8 Grease or oil consuming mechanical and hydraulic solutionsFrom specialized lubricants to state-of-the-art lubrication systems and lubrication management ser vices, lubrication solutions from SKF can help to reduce lubrication related downtime and lubricant and motion controlWith a wide assortment of products from actu-ators and ball screws to profile rail guides SKF can work with you to solve your most pressing linear system knowledge your successSKF Life Cycle Management is how we combine our technology platforms and advanced ser vices, and apply them at each stage of the asset life cycle, to help our customers to be more success ful, sustainable and closely with you Our objective is to help our customers improve productivity, minimize main ten-ance, achieve higher energy and resource efficiency, and optimize designs for long service life and reliability.

9 Innovative solutions Whether the application is linear or rotary or a combination, SKF engineers can work with you at each stage of the asset life cycle to improve machine performance by looking at the entire application. This approach doesn t just focus on individual components like bearings or seals. It looks at the whole application to see how each com po nent in-teracts with each optimization and verificationSKF can work with you to optimize current or new designs with proprietary 3-D mod-ell ing software that can also be used as a virtual test rig to confirm the integrity of the design. SKF Life Cycle ManagementDesign and developManufacture and testSpecificationInstall and commissionOperate and monitorMaintain and repair555 Planetary Roller screws SR/BR, HR: Standard and maximum dynamic load carrying capacity Ca [kN]NominalNut Lead [mm]diametertyped024568910121518mm kN 8SR/BR8,618,9312SR/BR 14,112SR/BR13,215,115SR/BR 2627,415SR/BR23,929,729,418SR/BR30,437,7 3821SR/BR 50,652,85759,221SR/BR47,457,860,365,263, 624SR/BR42,347,724SR/BR47,353,325SR/BR68 ,476,178,685,625SR/BR78,28789,891,930SR/ BR929510310611930SR/BR10510911712212736S R/BR90,597,510711436SR/BR10611512512839S R/BR12915316839SR/BR14817419244SR/BR1301 4415844SR/BR15316918548SR/BR198218232258 48SR/BR24025026529556SR/BR21256SR/BR2496 0SR/BR33937360SR/BR38742660HR49464SR/BR 31764SR/BR29633375SR50556175HR83680SR365 42080SR38344187HR1 05999SR99HR1 277112,5HR1 396120SR120HR1 547135HR1 843150HR2 200180HR3 073210HR240 HRSelection guide Standard number of rollers Maximum number of rollers, on request Preferred rangeSR (C, F or P).

10 Planetary Roller screw with axial playBR (C, F or P): Planetary Roller screw without backlashHR (C, F or P): Ultra Power planetary Roller screwC: Cylindrical nut, F: Centered flange, P: Off centered flange6 Planetary Roller screws SR/BR, HR: Standard and maximum dynamic load carrying capacity Ca [kN]NominalNut Lead [mm]diametertyped024568910121518mm kN 8SR/BR8,618,9312SR/BR 14,112SR/BR13,215,115SR/BR 2627,415SR/BR23,929,729,418SR/BR30,437,7 3821SR/BR 50,652,85759,221SR/BR47,457,860,365,263, 624SR/BR42,347,724SR/BR47,353,325SR/BR68 ,476,178,685,625SR/BR78,28789,891,930SR/ BR929510310611930SR/BR10510911712212736S R/BR90,597,510711436SR/BR10611512512839S R/BR12915316839SR/BR14817419244SR/BR1301 4415844SR/BR15316918548SR/BR198218232258 48SR/BR24025026529556SR/BR21256SR/BR2496 0SR/BR33937360SR/BR38742660HR49464SR/BR 31764SR/BR29633375SR50556175HR83680SR365 42080SR38344187HR1 05999SR99HR1 277112,5HR1 396120SR120HR1 547135HR1 843150HR2 200180HR3 073210HR240 HRNominalNut Lead [mm]