Slotted nut NMG. Housing nut GWR. Bosch Rexroth AG. for economical constructions. a min. 0,3. M A = tightening torque of slotted nut.

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1 R310EN 3301 ( ) Precision Ball Screw Assemblies Bosch Rexroth AG 113 Slotted nut NMG for economical constructions B D d d1 b M A = tightening torque of slotted nut a min. 0,3 Polyamide insert Designation Part number Dimensions M A Weight d D B d 1 a b (Nm) (g) NMG 12x1 R M12x NMG 15x1 R M15x NMG 20x1 R M20x Housing nut GWR for angular-contact thrust ball bearing LGN for cylindrical single nut ZEM-E-S Note: Use a threadlocker (e.g. Loctite 638) to secure against loosening. 0,01 A A D d B g f e Designation Part number Dimensions Weight D d B e f g (g) GWR 18x1 R M18x GWR 23x1 R M23x GWR 26x1.5 R M26x GWR 30x1.5 R M30x GWR 36x1.5 R M36x GWR 40x1.5 R M40x GWR 45x1.5 R M45x GWR 50x1.5 R M50x GWR 55x1.5 R M55x GWR 58x1.5 R M58x GWR 60x1 R M60x GWR 62x1.5 R M62x GWR 65x1.5 R M65x GWR 70x1.5 R M70x GWR 78x2 R M78x GWR 92x2 R M92x GWR 112x2 R M112x

2 114 Bosch Rexroth AG Precision Ball Screw Assemblies R310EN 3301 ( ) Technical Data Technical Notes DIN , Part 1 defines a ball screw as follows: 100 An assembly comprising a ball screw shaft and a ball nut and which is capable of converting rotary motion into linear motion and vice versa. The rolling elements of the assembly are balls. Advantages over the Acme screw drive The mechanical effi ciency of an Acme screw drive is a maximum 50%, whereas a ball screw can reach a mechanical effi ciency of up to 98%. Higher life expectancy due to negligible wear during operation Less drive power required No stick-slip effect More precise positioning Higher travel speed Less heat-up Effi ciency (%) = = 0.01 = 0. 2 = 0.3 Precision Ball Screw Assembly Acme screw Lead angle ( ) Due to their high mechanical effi ciency, ball screws are in principle not selflocking. c Safety information For vertically installed assemblies, customers should check whether separate protection against falling loads, e.g. a safety nut, is required. We recommend that a safety nut be installed for particularly critical applications in vertical set-ups. Please ask. Selection criteria for ball screws The following factors should be considered when selecting the ball screw for a given application: degree of accuracy required (lead deviation) in-service load conditions service life critical speed buckling load rigidity/permissible clearance or desired preload characteristic speed (max. permissible linear speed) The following points should be taken into consideration when selecting a ball screw assembly that is to be both costeffi cient and optimally designed: The lead is a decisive factor for the load-carrying capacity (depending on the maximum possible ball diameter) and the drive moment. The calculation of the service life should be based on average loads and average speeds, not on maximum values. In order for us to provide you with a customized solution, installation drawings or sketches of the ball nut environment should be enclosed with your inquiry. c Note Radial and eccentric forces relative to the screw must be avoided as they have a negative effect on the life and proper function of the ball screw. Where special conditions of use are involved, please ask.

3 R310EN 3301 ( ) Precision Ball Screw Assemblies Bosch Rexroth AG 115 Load-carrying capacities and service life We calculate load-carrying capacities and service life in accordance with DIN , Part 4 and ISO (P5). Basic static load rating C 0 The static load rating is an axial, concentrically acting force that induces a per-manent deformation of x the ball diameter between the ball and the ball raceway. Basic dynamic load rating C The dynamic load rating is an axial, concentrically acting force of constant magnitude and direction under which 90% of a suffi ciently large amount of identical ball screws can achieve a nominal service life of one million revolutions. Service life The nominal life is expressed by the number of revolutions (or number of operating hours at constant speed) that will be attained or exceeded by 90% of a representative sample of identical ball screws before the fi rst signs of material fatigue become evident. The nominal life is designated as L or L h, depending on whether it is specifi ed in revolutions or hours. Short stroke During a short stroke, the ball does not make a real turn. It is therefore impossible for an adequate lubricating fi lm to form. This may result in premature wear. In the chart, the minimum required stroke (travel) for a 10% lower load rating is shown as a function of the number of turns and lead of the nut. Hence the most favorable range lies above each curve. It may help to have occasional longer strokes, which are performed with simultaneous relubrication as lubricating strokes. If in doubt, please ask. Critical speed and buckling load The critical speed and buckling load can be checked using the corresponding charts. For precise calculations see formula 12 15, in Design Calculations Characteristic speed n Rexroth ball screws can be operated at very high speeds due to their internal ball recirculation system. Characteristic speeds of up to 150,000 are possible depending on the nut type. n 150,000 n 80,000 (for eline and ECOplus series) = nominal diameter n = speed (min 1 ) The theoretically possible maximum linear speed v max (m/min) is specifi ed on the page featuring the relevant nut. Actually attainable speeds are heavily dependent among other factors on preload and duty cycle. They are gen-erally restricted by the critical speed. (See Design Calculations ) Material, hardness Our standard ball screw assemblies are made of high-quality, heat-treatable steel, carbon chrome alloy steels or case-hardened steels. The screw and nut raceways have a minimum Rockwell hardness of HRC 60. Ball screw assemblies made of corrosion-resistant steel (DIN EN ISO ) are also available upon request. Unless otherwise specifi ed, the screw ends are not hardened. Sealing Ball screws are precision assemblies that require protection against contamination. Flat protective covers and bellows type dust boots or the drive Short stroke limit (load rating reduced by less than 10%) Stroke (travel) unit AGK are particularly suitable for this purpose. As there are many applications in which these methods do not provide suffi cient protection, we have developed a gapless lip-type seal which ensures an optimal sealing effect and maintains high effi ciency due to the low friction level. Our ball screws are therefore supplied with seals in their standard versions. At the customer s request, these seals can be omitted or special seals used in their place. A reinforced version of the standard seal has been developed for those applications where heavy contamination of the screw ap-pears inevitable. The sealing effect has been improved further by increasing the preload. What must be borne in mind is the signifi cantly higher friction torque in comparison with the standard friction torque (see Technical Data) and the associated increased heat build-up. The reinforced seal can be easily recognized externally by its dark green color. Permissible operating temperatures Ball screws are suitable for continuous operation at temperatures up to 80 C with temporary peaks of 100 C (measurements taken on the outer shell of the nut). Permissible operating temperatures: 10 C T operating 80 C Permissible bearing temperature: 15 C T bearing 80 C Lead Number of ball track turns in the nut i ,5

4 116 Bosch Rexroth AG Precision Ball Screw Assemblies R310EN 3301 ( ) Technical Data Acceptance Conditions and Tolerance Grades T Note: For eline Ball Screws, please refer to the data given in the eline Ball Screw Assemblies section. Ball screw with precision-rolled screw SN-R l' e l 1 l u l' e l 0 Permissible travel deviation in accordance with DIN , Part 3 and ISO Many values are signifi cantly more accurate than those defi ned in DIN , Part 3 and ISO ν300p e'p Symbol definitions (excerpt): l 0 = nominal travel l 1 = thread length l 0 = travel deviation l u = useful travel l' e = excess travel (the closer tolerances for travel and hardness do not apply here) c = travel compensation (target travel deviation) (standard: c = 0) e' p = tolerance mean actual travel deviation ν 300p = permissible travel deviation within 300 mm travel ν 2πp = permissible travel deviation within one revolution l 0 2πrad 2πp ν' e'p c = 0 Improved values compared with DIN , Part 3 and ISO (tolerance reduced by half) Useful travel l u tolerance mean actual travel deviation e' p ( m) Tolerance grade l e' u p ν p For precision screws SN-R the following values apply in all cases: 300p ( m) Tolerance grade ' 2 p ( m) Tolerance grade Non-usable length l' e (Excess travel) Modifi ed with respect to DIN l' e , , 25, 32, , 63, 80 50

5 R310EN 3301 ( ) Precision Ball Screw Assemblies Bosch Rexroth AG 117 Minimum number of measurements within 300 mm (measuring interval) and excess travel to be taken into consideration Lead P Minimum number of measurements for tolerance grade

6 118 Bosch Rexroth AG Precision Ball Screw Assemblies R310EN 3301 ( ) Technical Data Acceptance Conditions and Tolerance Grades Run-outs and location deviations based on DIN , Part 3 and ISO Radial run-out t 5 of the outer diameter of the ball screw shaft over the length l 5 used to determine the straightness in relation to AA'. A l5 l5 l5 AA' t 5p A' 2 l 5 t 5p in µm for l 5 for tolerance grade above up to 5 7; 9 = t 5p A 2 l 1 l5 l5 t 5 max A l 1 / t 5max in µm for l 1 4l 5 for tolerance grade above up to 5 7; Radial run-out t 6 of the bearing diameter in relation to AA' for l 6 l. Table value t 6p applies when I 6 reference length I. Where l 6 > l then t 6a t 6p l 6a l t 6p AA' A 2 l 6 A' Nominal diameter Reference length l t 6p in µm for l 6 l for tolerance grade above up to 5; 7; 9 = Coaxial deviation t 7 ' of the journal diameter of the ball screw shaft in relation to the bearing diameter for l 7 l. Table value t 7p applies when I 7 reference length I. Where l 7 > l then t 7a t 7p l 7a l l 7 C t 7p ' C Bearing seat Nominal diameter Reference length l t 7p ' in µm for l 7 l for tolerance grade above up to 5; 7; 9 =

7 R310EN 3301 ( ) Precision Ball Screw Assemblies Bosch Rexroth AG 119 Axial run-out t 8 ' of the shaft (bearing) face of the ball screw shaft in relation to the bearing diameter. t 8p ' C d C Bearing seat F t 8p ' in µm Nominal diameter for tolerance grade above up to 5; 7; 9 = Axial run-out t 9 of the ball nut location face in relation to A and A' (for preloaded ball nuts only). A D 5 2 t 9p AA' A' 2 F t 9p in µm Flange diameter D 5 for tolerance grade above up to 5; 7; Radial run-out t 10 of the outer diameter D 1 of the ball nut in relation to A and A' (for preloaded and rotating ball nuts only). Fix screw against rotation before carrying out the measurement. A 2 D 1 t 10p AA' Fixed A' 2 t 10p in µm Outer diameter D 1 for tolerance grade above up to 5; 7; Please ask for details of permissible axial and radial run-out for driven nuts.

8 120 Bosch Rexroth AG Precision Ball Screw Assemblies R310EN 3301 ( ) Technical Data Preload and Rigidity Nut system preload In addition to single nuts with reduced backlash, Rexroth supplies preloaded or adjustable-preload nut systems. Axial movement (defl ection) Single nut with backlash Preloaded and adjustablepreload nut systems Axial load The rigidity of these types of Rexroth nut systems is approximately the same at the same preload. This is because the adjustable-preload single nut and the preloaded single nut have a much more compact design. The screw is typically far less rigid than the nut unit (for details see Overall axial rigidity... ). Preloaded single nut Single nuts can be preloaded to 2%,3% or 5% of the basic dynamic load rating by means of optimized ball size selection. Adjustable-preload single nut The adjustable-preload single nut allows cost-effi cient design techniques to be implemented in a large number of applications. The radial clearance and preload are adjusted radially via a slot approx. 0.1 mm wide, see section Mounting. Depending on the application, we will preload the nut system to 2%, 3% or 5% of the basic dynamic load rating. The maximum preload equals approx. 5% of the basic dynamic load rating. Double nut Tensioning two single nuts against each other eliminates the inherent backlash of the ball screw, increases rigidity and thus improves positioning accuracy. As excessive preload can cause a reduction in service life, we recommend that it not be more than 1 / 3 of the average operating load. Depending on the application, we will preload the nut system to 7% or 10% of the basic dynamic load rating. Driven nut Like the single nut, the driven nut from the Drive Units catalog R310EN 3304 can be preloaded to 2%, 3% or 5% of the basic dynamic load rating by means of ball size selection. 2-start single nut with flange The 2-start single nut with fl ange is optimally preloaded to 2% or 3% of the dynamic load rating by means of ball size selection.

9 R310EN 3301 ( ) Precision Ball Screw Assemblies Bosch Rexroth AG 121 Overall rigidity The rigidity of a ball screw is also infl u- enced by all adjoining parts such as bearings, housing bores, nut housings etc. Rigidity of the screw R S The rigidity of the screw R S depends on the type of bearing used. See the corresponding tables for rigidity values. Overall axial rigidity R bs of the ball screw The overall axial rigidity R bs is comprised of the component rigidity of the bearing R fb, the screw R S and the nut unit R nu. 1 Ball screw shaft is fi xed at one end. 2 Ball screw shaft is fi xed at both ends = + + R bs R fb R S R nu 16 l S1 S S2 2 l S2 l S Note: Please note that in most cases the rigidity R S of the screw will be signifi cantly lower than the rigidity R nu of the nut unit. In an assembly with a diameter of 40 x 10, for example, the rigidity R nu of the nut unit is 2 to 3 times higher than the rigidity R S of a screw with a length of 500 mm. D w d2 d1 R S2 165 (-0.71 D w) S2 18 The lowest screw rigidity R S2min occurs at the center of the screw (l S2 = l S /2) and thus equals: 2 S (N/µm) S S2 Rigidity of the bearing R fb The rigidity of the bearings corresponds to the values found in the bearing manufacturer s catalog. RS1 165 (-0.71 D w) S1 2 (N/µm) 17 ( D w ) R 660 (N/µm) S2min S 2 19 See the corresponding tables in this catalog for rigidity values of the bearings offered by Rexroth. Rigidity in the area of the nut unit R nu The rigidity in the area of the nut unit is calculated according per DIN (P5). See the corresponding tables for rigidity values. R S1 = rigidity of the screw = nominal diameter D W = ball diameter l S1 = distance between bearing and nut (N/ m) R S2 = rigidity of the screw = nominal diameter D W = ball diameter l S = distance between bearing and bearing l S2 = distance between bearing and nut (N/ m)

10 122 Bosch Rexroth AG Precision Ball Screw Assemblies R310EN 3301 ( ) Technical Data Preload and Overall Rigidity of Single Nuts Dynamic drag torque, preload and rigidity for screws of tolerance grade 5-7 with single nuts from diameter 16 mm (smaller diameters without backlash only) FSZ-E-S, FEP-E-S (2% only), FEM-E-S, FEM-E-C, ZEM-E-S; SEM-E-S and SEM-E-C (consider centering diameter D 1 to be set) (ZEV-E-S and FBZ-E-S with backlash only!) T 0 T 0 = overall dynamic drag torque = T pr0 + T RD C = basic dynamic load rating C 0 = basic static load rating T RD = dynamic drag torque of 2 seals R S = rigidity of the screw R nu = rigidity of the nut T pr0 = dynamic drag torque without a seal = nominal diameter P = lead D w = ball diameter i = number of ball track turns The values given for dynamic drag torque are proven practical indicators for the nut preloading. Note: Measurement of the dynamic load torque, see Mounting. Size Load ratings Backlash of single nut Overall rigidity of the screw dyn. C stat. C 0 Standard Reduced R S (N) (N) N m D 0 x P x D W - i ( µm ) 6 x 1R x x 2R x x 1R x x 2R x x 2.5R x x 2R x x 5R x x 10R x x 5R/L x x 10R x x 16R x x 16R x x 5R/L x x 5R x x 10R x x 20R/L x x 20R x x 40R x x x 5R/L x x 10R x x 25R/L x 25R x x 25R x x x 5R/L x x 10R x x 20R x x 20R x x 32R x x 32R x x 32R x x x 64R x x x 5R/L x x 10R/L x x 10R x x 12R x x 16R x x 20R x x 20R x 6-4 x x 40R x x 40R x x 40R x 6-3 x x 5R x x 10R x x 10R x x 12R x x 16R x x 20R x x 20R x x 20R x x x 25R x x x 40R x x 40R x x x 40R x x 10R x x 10R x x 20R x x 20R x x 20R x x x 40R x x 40R x x 40R x x x 10R x x 20R x

11 R310EN 3301 ( ) Precision Ball Screw Assemblies Bosch Rexroth AG 123 Size Screws with single nuts 2% preload 3% preload 5% preload R nu T pr0 R nu T pr0 R nu T pr0 (N/ m) (Nm) (N/ m) (Nm) (N/ m) (Nm) Tolerance grade 5; 7 Tolerance grade 5; 7 Tolerance grade 5 Tolerance grade 7 D 0 x P x D W - i max. max. min. max. min. max. min. max. 6 x 1R x x 2R x x 1R x x 2R x x 2.5R x x 2R x x 5R x x 10R x x 5R x x 10R x x 16R x x 16R x x 5R/L x x 5R x x 10R x x 20R/L x x 20R x x 40R x x x 5R/L x x 10R x x 25R/L x x 25R x x 25R x x x 5R/L x x 10R x x 20R x x 20R x x 32R x x 32R x x 32R x x x 64R x x x 5R/L x x 10R/L x x 10R x x 12R x x 16R x x 20R x x 20R x 6-4 x x 40R x x 40R x x 40R x 6-3 x x 5R x x 10R x x 10R x x 12R x x 16R x x 20R x x 20R x x 20R x x x 25R x x x 40R x x 40R x x 40R x x x 10R x x 10R x x 20R x x 20R x x 20R x x x 40R x x 40R x x 40R x x x 10R x x 20R x

12 124 Bosch Rexroth AG Precision Ball Screw Assemblies R310EN 3301 ( ) Preload and Rigidity of Double Nuts Dynamic drag torque, preload and rigidity for screws of tolerance grade 5-7 with double nuts FDM-E-S, FDM-E-C T 0 T 0 = overall dynamic drag torque = T pr0 + T RD C = basic dynamic load rating C 0 = basic static load rating T RD = dynamic drag torque of 2 seals R S = rigidity of the screw R nu = rigidity of the nut T pr0 = dynamic drag torque without a seal = nominal diameter P = lead D w = ball diameter i = number of ball track turns The values given for dynamic drag torque are proven practical indicators for the nut preloading. Note: Measurement of the dynamic load torque, see Mounting. Size Load ratings Rigidity of the screw R S dyn. C stat. C 0 N m ( µm ) D 0 x P x D W - i (N) (N) 16 x 5R x x 5R x x 5R x x 10R x x 5R x x 10R x x 5R x x 10R x x 10R x x 20R x x 5R x x 10R x x 10R x x 20R x x 10R x x 10R x x 20R x x 10R x x 20R x

13 R310EN 3301 ( ) Precision Ball Screw Assemblies Bosch Rexroth AG 125 Size Screws with double nuts FDM-E-S, FDM-E-C R nu (N/ m) 7% preload 10% preload T pr0 R nu T pr0 (Nm) (N/ m) (Nm) Tolerance grade 5 Tolerance grade 7 Tolerance grade 5 Tolerance grade 7 D 0 x P x D W - i min. max. min. max. min. max. min. max. 16 x 5R x x 5R x x 5R x x 10R x x 5R x x 10R x x 5R x x 10R x x 10R x x 20R x x 5R x x 10R x x 10R x x 20R x x 10R x x 10R x x 20R x x 10R x x 20R x

14 126 Bosch Rexroth AG Precision Ball Screw Assemblies R310EN 3301 ( ) Technical Data Friction Torques of Seals Seal torque for single and double nuts (ZEV-E-S is supplied without a seal) T 0 = overall dynamic drag torque T 0 = T pr0 + T RD T RD = dynamic drag torque of 2 seals T pr0 = dynamic drag torque without a seal = nominal diameter P = lead D w = ball diameter Note: Measurement of the dynamic load torque, see Mounting. Size x P x D W Dynamic drag torque Standard Reinforced seal seal T RD approx. T RD approx. Low-friction seal Standard seal for 2-start single nuts with flange T RD approx. (Nm) (Nm) (Nm) 6 x 1R x x 2R x x 1R x x 2R x x 2.5R x x 2R x x 5R x x 10R x x 5R x x 10R x x 16R x x 20 x 5R x x 20 x 5L x x 20 x 10R x x 20R x x 20L x x 40R x x 5R x x 5L x x 10R x x 25R x x 25L x x 5R x x 32 x 5L x x 32 x 10R x x 32 x 20R x x 32 x 32R x x 40 x 5R x x 40 x 5L x x 10R x x 40 x 10L x x 40 x 12R x x 16R x x 20R x x x 40R x x x 5R x x 10R x x 12R x x 16R x x 20R x x 25R x x 40R x x 10R x x 20R x x 40R x x 10R x x 20R x Gap seal (0 Nm) Seal available x Seal in preparation