B-1 SLIDE GUIDE STROKE BALL SPLINE ROTARY BALL SPLINE BALL SPLINE TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT SLIDEROTARYBUSH STROKE BUSH SLIDE SHAFT

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1 SLIDE GUIDE TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT B-1

2 The NB ball spline is a linear motion mechanism utilizing the rotational motion of ball elements. It can be used in a wide variety of applications including robotics and transport type equipment. STRUCTURE AND ADVANTAGES The NB ball spline consists of a spline shaft with raceway grooves and a spline nut. The spline nut consists of an outer cylinder (main body), retainer, side rings, and ball elements. Designed and manufactured to achieve a reliably smooth motion. High Load Capacity and Long Travel Life: The raceway grooves are machined to a radius close to that of the ball elements. The large ball contact area results in high load capacity and long travel life. Wide Variety of Configurations: shaft sizes with diameters from 4 to 1 are available. Seven different types of nuts are available: cylindrical types (SSP/SSPM), flange types (SSPF/SSPT), and block types (SPA/SPA-W/SSPB). Material option of Stainless steel(44c or equivalent) is also available. They can be specified to suit various applications. Transmission of Torque: NB ball splines can sustain loads in several directions simultaneously. They can be used as a single shaft system and can transmit (or resist) torque. Ease of Additional Custom Machining: Since a round shaft with raceway grooves is used, NB ball spline shafts can be machined easily to customized specifications. High-Speed Motion and High-Speed Rotation: The outer cylinder is compact and well balanced, resulting in good performance at high speed. Figure B-1 Basic Structure of NB Ball Spline outer cylinder side ring with side-seal spline shaft retainer ball elements B-2

3 SLIDE GUIDE TYPE TYPES OF SPLINE NUT: A wide variety of spline nut designs are available and all spline nuts come with a side-seal as a standard feature. Table B-1 Types of Spline Nut type of nut cylindrical type SSP SSPS shape and advantage cylindrical spline nut with key groove with special key nominal diameter: SSP4-1 : SSPS4- page number for dimension table P.B- TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT SSPM cylindrical spline nut without key groove with two lock plates for fixing nominal diameter: 6-1 P.B-18 flange type SSPF SSPFS spline nut with flange nominal diameter: SSPF6-6 : SSPFS6- P.B-2 SSPT B-3 spline nut with a two side cut flange nominal diameter: 6-1 P.B-22

4 Table B-2 Types of Spline Nut type of nut shape and advantage page number for dimension table SPA aluminum housing lightweight and compact with keyless spline nominal diameter: 6-1 P.B-24 aluminum housing can sustain high moment loading block type SPA-W with two keyless splines with grease fitting nominal diameter: 6-1 P.B-26 cast block spline grooves are machined SSPB directly on main body high rigidity with grease fitting nominal diameter: 2-4 P.B-28 B-4

5 SLIDE GUIDE TYPES OF SPLINE SHAFT: Depending on the application requirements, either a fully machine ground spline shaft or a coercial grade spline shaft can be specified. Table B-3 Types of Spline Shaft type of spline shaft ground spline shaft shape and advantage precision-ground and precision machined surface finish high precision possible to machine ends of spline shaft and surface finish nominal diameter: 4-1 TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT standard spline shaft standard dimension and shape accuracy grade: high grade short lead time nominal diameter: 4-6 (Refer to page B-3) coercial shaft (non-ground) for general industrial use with special finished raceway surface low cost possible to machine ends of spline shaft and surface finish nominal diameter: 2-5 maximum length: 5 (Refer to page B-31) B-5

6 ACCURACY The NB ball spline is measured for accuracy at points shown in Figure B-2 and categorized as either highgrade or precision-grade (P). Contact NB for accuracy information on the coercial type ball spline. Table B-4 Tolerance of Spline Shaft and groove torsion type of shaft ground shaft accuracy grade high precision (P) m/1 6m/1 Figure B-2 Accuracy Measurement Points support area part attachment area spline nut spline shaft support area part attachment area Note: The support area is the portion where, for example, radial bearings are attached in order to support the spline shaft. The part attachment area is the portion to which other parts, such as gears are attached. Table B-5 Tolerance of Parts Relative to Spline Support Area (Max.) radial run-out of part attachment area perpendicularity of the end of the spline shaft section high-grade precision-grade high-grade precision-grade SSP4 SSP SSP8 9 6 SSP SSP A SSP A SSP 2A SSP SSP A SSP 22 9 SSP 3 SSP 4 SSP SSP 6 SSP 88L SSP11L unit/m perpendicularity of the flange high-grade precision-grade B-6

7 SLIDE GUIDE Table B-6 Radial Run-Out of Outer Surface of Spline Nut Relative to Spline Shaft Support Area (Max.) total length of spline shaft () greater than , 1, 1,6 or less , 1, 1,6 2, highgrade highgrade SSP4 SSP6 SSP8 precision grade SSP1 highgrade precision grade SSPA SSPA highgrade precision grade SSP2A SSP2 SSPA SSP SSP3 highgrade Both the clearance and pre-load are expressed in terms of clearance in the rotational direction. The pre-load is categorized into three different levels : standard, light (T1), and medium (T2). A pre-load cannot be specified when using the coercial grade spline shaft. B-7 precision grade highgrade precision grade SSP4 SSP5 highgrade precision grade highgrade SSP6 SSP8 SSP8L precision grade SSP4 maximum fabrication length: 3; SSP6 maximum fabrication length: 4; SSPA, A maximum fabrication length: 15 For lengths exceeding 2, contact NB SSP1 SSP1L unit/m PRE-LOAD AND CLEARANCE IN ROTATIONAL DIRECTION Table B-7 Pre-Load and Clearance in Rotational Directionunit/m SSP4 SSP6 SSP8 SSP 1 SSP A SSP A SSP 2A SSP 2 SSP A SSP SSP 3 SSP 4 SSP 5 SSP 6 SSP 8(L) SSP1(L) standard light (T1) medium (T2) Table B-8 Operating Condition and Pre-Load pre-load standard light medium pre-load symbol T1 T2 operating condition precision grade Minute vibration is applied. A precise motion is required. A torque in a given direction is applied. Slight vibration is applied. Slight torsional load is applied. Cyclic torque is applied Shock/vibration is applied. Over-hang load is applied. Torsional load is applied. TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT

8 LIFE CALCULATION Because ball elements are used as the rolling elements in ball splines, the following equations are used to calculate the life of ball spline systems. Figure B-3 Radial Loading and Torque Loading radial load For radial load fc C fw P L= 5 3 torque load For torsional load fc CT fw T L= 5 L : travel life (km) fc : contact coefficient fw: Load coefficient C : basic dynamic load rating(n) P : load(n) CT : basic dynamic torque rating(n-m) T : torque(n-m) * Refer to page Eng-5 for coefficients ** The rated load for the coercial spline shaft is approximately 7% of the standard ball spline shaft. OPERATING ENVIRONMENT 3 moment Figure B-4 Examples of Dust Prevention Methods The performance of a ball spline system is affected by the operating condition and environment of the application. The operating conditions should therefore be carefully taken into consideration. Dust Prevention: The invasion of foreign particles and dust may affect the motion characteristics and shorten the life of a ball spline. Seals will perform well under normal operating conditions. However, they may not prevent the entry of foreign particles in a hostile environment. When used in such an environment, the ball spline should be protected using bellows and protective covers. Operating Temperature: The ball retainers used in ball spline nuts are made of resin, so the operating temperature should never exceed 8 o C. bellows cover Excessive Moment: The allowable load for ball splines is high, and they can also sustain high moment load. However, when the load becomes excessive, the load applied to the raceway grooves becomes unbalanced and stable motion may not be achieved. When accuracy is required, the application of excessive moment should be prevented by using two or more spline nuts. B-8

9 SLIDE GUIDE LUBRICATION Both ends of the spline nut have a side-seal as a standard feature. For the fully ground spline shaft, the side-seals are positioned against the spline shaft so as to prevent the lubricant from leaking out of the spline nut. Lithium soap grease is applied to NB ball spline nuts before shipping, so there is no need to apply lubricant at the time of installation. However, a small amount of lubricant may be lost during operation, so the lubricant needs to be replenished periodically. SPECIAL REQUIREMENTS NB will fablicate custom shafts, spline nut, surface finish, etc. to meat customer requirements. For hollow spline shafts, recoended standard inner diameters are listed in Table B-9. Contact NB for details. Figure B-6 Example of End-Machining Figure B-5 Example of Lubrication Mechanism Table B-9 Recoended Inner Diameter for Hollow Spline Shaft SSP 4 SSP 6 SSP 8 SSP 1 SSP A SSP A shaft diameter DS inner diameter d crosssectional coefficient Z second moment of inertia I ,26 2,78 TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT B-9

10 Fit: A transition fit between an SSP/SSPM-type spline nut and its housing bore is used to minimize the clearance. If high accuracy is not required, then a clearance fit is used. For the SSP/SSPM type spline nuts, if only a light load is to be applied, a hole slightly larger than the outer diameter of the nut will suffice. Insertion of Spline Nut: When inserting a spline nut into the housing, use a jig, example as shown in Figure B-7. Carefully insert the nut so as not to hit the side ring and side-seal. Table B-11 Recoended Jig Dimensionsunit/ SSP 4 SSP 6 SSP 8 SSP1 SSPA SSPA SSP2A SSP2 SSPA MOUNTING D d SSP SSP 3 SSP 4 SSP 5 SSP 6 SSP 8 SSP 8L SSP1 SSP1L D d Table B-1 Fit for the Spline Nut type of spline nut clearance fit transition fit SSP SSPM H7 J6 Figure B-7 Insertion of Spline Nute into Housing jig Insertion of Spline Shaft: Insertion of Spline Shaft: When inserting the spline shaft into the spline nut, ensure that the ball elements do not drop out. This is accomplished by aligning the raceway grooves of the shaft with the rows of ball elements in the nut. Then simply insert the spline shaft through the spline nut. B-1

11 SLIDE GUIDE Mounting of SSP Type Spline: Example methods for installing the SSP type spline are shown in Figures B-8 and B-9. Figure B-8 Using a Retaining Ring Key: The SSP type spline comes with a key, as shown in Figure B-1. Figure B-9 Using a Push Plate Figure B-1 Key for SSP Type Spline TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT Table B-12 Major Dimensions of Key (SSP Type) a m SSP4 2 SSP6 2.5 SSP SSP 1 3 SSP A 3 SSP A 3.5 SSP 2A 24 SSP SSP A SSP 5 SSP SSP SSP 5 15 SSP SSP 8 18 SSP 8L SSP SSP1L h B-11 m 3 36 / L R k

12 Mounting of SSPM Type Spline: Example methods for installing the SSPM spline are shown in Figures B-11 to B-14. Figure B-11 Using an F Type Lock Plate Figure B-12 Using an LP Type Lock Plate Figure B-14 Using a Special Lock Plate (2) Figure B- Using a Special Lock Plate (1) B-12

13 SLIDE GUIDE F Type Lock Plate (Standard Part): The lock plate shown in Figure B-15 is provided with the SSPM spline. Material: SUS34CSP Table B- F Type Lock Plate FP 6 FP 8 FP1 K G t LP Type Lock Plate (Purchased Separately): An LP type lock plate is also available for use with the SSPM spline. Material: SUS34CSP Figure B- LP Type Lock Plate R applicable spline nut SSPM 6 SSPM 8 SSPM1 Figure B-15 F Type Lock Plate TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT 2C.3 or more When using the LP type lock plate, machine the housing as shown. Table B-14 LP Type Lock Plate LP 6 LP 8 LP1 K lock plate major dimensions G t R X Y B- machined housing dimensions B E GM M M2.5 M3 M3 applicable spline nut SSPM 6 SSPM 8 SSPM1

14 Mounting of SSPF Type Spline: Example methods for installing the SSPF spline are shown in Figure B-17. Figure B-17 Example Methods for installing SSPF Type Spline Mounting of SSPT Spline: Example methods for installing the SSPT spline are shown in Figure B-18. Figure B-18 Example Methods for installing SSPT Type Spline B-14

15 SLIDE GUIDE Mounting of Block Type Spline: Example methods for installing the block spline are shown in Figure B-19. Figure B-19 Example Methods for installing Block Type Spline SPA type SPA-W type TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT SSPB type B-15

16 SSP TYPE Cylindrical Spline Nut structure example SSP 8 L T1-6 - P / CU SSP type nominal diameter nut length blank standard L long number of nuts attached to one shaft with special specification accuracy grade blank high P precision spline shaft total length pre-load symbol blank T1 T2 standard light medium When two spline nuts are used in close contact. major dimensions standard anticorrosion D m L B b m t.5 L1 d Ds m SSP4 SSPS4 SSP6 SSPS6 SSP8 SSPS8 SSP 1 SSPS 1 SSP A SSPS A SSP A SSPS A / SSP 2A SSPS 2A SSP 2 SSPS 2 SSP A SSPS A SSP SSPS SSP 3 SSP 4 SSP SSP 6 SSP 8 SSP 8L SSP1 SSP1L B-

17 SLIDE GUIDE (oil hole) key groove key groove (oil hole) SSP4 spline nut does not come with an oil hole. key groove (oil hole) SSP88L11L TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT basic torque rating dynamic static CT COT Nm Nm basic load rating dynamic static C Co kn kn allowable static moment M1 M2 Nm Nm second crosssectional moment of inertia 4 crosssectional coefficient 3 nut kg mass shaft kg/m SSP SSP6 SSP8 SSP 1 SSP A SSP A , ,47 2, SSP 2A SSP 2 SSP A SSP SSP 3 SSP 4 1,39 3, , SSP 5 2,1 3,86 5,12 6,75 8,96 4,8 6,23 9,34 11,57 17, ,3 2, 4,41 3,36 7,34 8,8 11,1 21,1 19,3 37,7 B SSP 6 SSP 8 SSP 8L SSP1 SSP1L 1kN12kgf1Nm.12kgfm

18 SSPM TYPE Keyless Spline Nut structure example SSPM T1-2 - P / CU SSPM type nominal diameter number of nuts attached to one shaft pre-load symbol blank standard T1 light with special specification accuracy grade blank high P precision spline shaft total length When two spline nuts are used in close contact. major dimensions D L F W C A d B H K G m SSPM 6 SSPM 8 SSPM / B-18

19 SLIDE GUIDE (oil hole) TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT t 1. 6 basic torque rating Ds dynamic static CT COT m Nm Nm / basic load rating dynamic static C Co kn kn allowable static moment M1 Nm 5.1 M2 Nm 4 second crosssectionasectional cross- moment of coefficient inertia mass nut shaft kg kg/m part number SSPM SSPM SSPM1 1kN12kgf1Nm.12kgfm B-19

20 SSPF TYPE Flange Type Nut structure example SSPF T P / CU SSPF type nominal diameter number of nuts attached to one shaft pre-load symbol blank standard T1 light T2 medium with special specification accuracy grade blank high P precision spline shaft total length When two spline nuts are used in close contact. major dimensions standard anticorrosion SSPF 6 SSPFS 6 SSPF 8 SSPFS 8 14 D m 11 L Df 3 32 H 5 5 P.C.D d1d2h W d 1 SSPF1 SSPFA SSPFA SSPFS1 SSPFSA SSPFSA SSPF2A SSPFS2A SSPF2 SSPFA SSPFS2 SSPFSA SSPF SSPFS SSPF3 SSPF4 SSPF SSPF6 9 / B-2

21 SLIDE GUIDE mounting hole x 4 2- d (oil hole) 2- d (oil hole) TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT SSP6 1 SSPA 6 DS basic torque rating basic load rating dynamic static CT COT m Nm Nm dynamic static C Co kn kn allowable static moment M1 M2 Nm Nm second crosssectional moment of inertia 4 crosssectional coefficient 3 mass nut shaft kg kg/m 6 / SSPF SSPF 8 SSPF1 SSPFA SSPFA , , SSPF2A SSPF2 SSPFA SSPF SSPF / ,39 2, ,18 4, , ,4 1,3 8,8 B SSPF SSPF SSPF6 1kN12kgf1Nm.12kgfm

22 SSPT TYPE Two Side Cut Flange Type structure example SSPT T P / CU SSPT type nominal diameter number of nuts attached to one shaft pre-load symbol blank standard T1 light with special specification accuracy grade blank high P precision spline shaft total length When two spline nuts are used in close contact. major dimensions D L Df B H P.C.D. d1d2h W d m SSPT 6 SSPT 8 SSPT / B-22

23 SLIDE GUIDE mounting hole x 2 (oil hole) TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT DS basic torque rating basic load rating dynamic static CT COT m Nm Nm dynamic static C Co kn kn allowable static moment M1 M2 Nm Nm second crosssectional moment of inertia 4 crosssectional coefficient 3 mass nut shaft kg kg/m / SSPT SSPT SSPT1 1kN12kgf1Nm.12kgfm B-23

24 SPA TYPE Keyless Block Type structure example SPA T1-2 / CU SPA type nominal diameter number of nuts attached to one shaft pre-load symbol blank standard T1 light with special specification spline shaft total length When two spline nuts are used in close contact. major dimensions h E W L F L1 T B C S D SPA M SPA M3 5 SPA M B-24

25 SLIDE GUIDE NB mark TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT 6 basic torque rating Ds dynamic static m /12 CT COT Nm Nm 2.4 basic load rating dynamic static C Co kn kn allowable static moment M1 M2 Nm Nm second crosssectionasectional cross- moment of coefficient inertia mass nut shaft kg kg/m part number SPA SPA SPA1 1kN12kgf1Nm.12kgfm B-

26 SPA-W TYPE Keyless Block Double Type structure example SPA 1 W T1-2 / CU SPA type nominal diameter double-wide type number of nuts attached to one shaft with special specification spline shaft total length pre-load symbol blank standard T1 light major dimensions h E W L F L1 T Gw B C S SPA 6W M3 5 SPA 8W M3 5 SPA1W M4 6 B-26

27 SLIDE GUIDE NB mark TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT D 14 6 Ds m /12 basic torque rating dynamic static CT COT Nm Nm basic load rating dynamic static C Co kn kn allowable static moment M1 Nm 4 second crosssectional moment of inertia crosssectional coefficient mass nut shaft kg kg/m part number SPA 6W SPA 8W SPA1W 1kN12kgf1Nm.12kgfm B-27

28 SSPB TYPE Block Type structure example SSPB T P / CU SSPB type nominal diameter number of nuts attached to one shaft pre-load symbol blank T1 T2 standard light medium with special specification accuracy grade blank high P precision spline shaft total length When two spline nuts are used in close contact. major dimensions h B L E b T P1 P2 S T1 SSPB M SSPB M SSPB M SSPB M B-28

29 SLIDE GUIDE TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT basic torque rating Ds dynamic static m 21 / CT COT Nm Nm basic load rating dynamic static C Co kn kn allowable static moment M1 M2 Nm Nm , ,94 second crosssectionasectional cross- moment of coefficient inertia nut kg mass shaft kg/m part number SSPB2 SSPB SSPB3 SSPB4 1kN12kgf1Nm.12kgfm B-29

30 STANDARD SPLINE BALL structure example SPA 1 W S T1-4 nut shape SSP cylindrical type SSPM key less type SSPF flange type two side cut SSPT flange type aluminum SPA block type SSPB block type nominal diameter standard length L pre-load symbol blank standard T1 light T2 medium number of nuts attached to one shaft standard spline shaft double-wide type heat-treated area heat-treated area major dimensions nominal Ds d standard length diameter L m m A A A A /3 15 / , ,15 1, ,15 1,35 Tolerance of length L for nominal diameter sizes 4-A: JIS B45 coarse grade. Refer to dimensional tables for nut shape and dimensions. applicable nut SSP SSPM SSPF SSPT W - SPA SPA SSPB , 1, 85 1,15 yes no B-3

31 SLIDE GUIDE COMMERCIAL SPLINE BALL structure example SSPF C / CU nut shape SSP cylindrical type SSPF flange type SSPB block type nominal diameter with special specification spline shaft total length number of nuts attached to one shaft coercial spline shaft TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT nominal diameter 2 Ds major dimensions standard length L 1, 2, 3, 4, 5, SSP SSPM applicable nut SSPF SSPT SPA W - SPA SSPB , 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, of total length and length of splined portion yes no total length less than 4: JIS B45 coarse grade total length greater than 4,: +/- 5. Please specify for s other than those above. Refer to dimensional tables for nut shape and dimensions When a coercial shaft is used, the rated load for the nut is about 7% that indicated in the dimensional tables. B-31

32 The NB rotary ball spline can be used for both rotational motion and linear motion. It can be used in SCARA robots, the vertical shaft of assembly equipment, and tool changers and loaders. STRUCTURE AND ADVANTAGES The NB rotary ball spline consists of a spline shaft and a nut. The nut has a spline portion and a rotating portion using cross rollers. Reduced Number of Parts: Because of the single-body construction consisting of the rotating portion and the spline portion, the number of parts is reduced so that the accumulated error is reduced as well. Substantial Reduction in Installation Cost: The use of cross roller elements keeps the housing thickness to a minimum, making the ball spline light and easy to install. High Rigidity: The cross roller elements and 4-row ball circuit structure provides high rigidity in spite of the compact design. Compact and Light: The cross rollers are directly attached to the ball spline's external cylinder, resulting in a compact and light design. High Accuracy: The cross roller elements ensure accurate positioning in the rotational direction. Figure B-2 Structure of NB Rotary Ball Spline seal installation flange side-seal spline shaft ball elements retainer cross roller elements B-32

33 SLIDE GUIDE ACCURACY The accuracy of the NB rotary ball spline is measured as shown in Figure B-21. Figure B-21 Accuracy Measurement Points support area part attachment area Note: The support area is the portion that supports the shaft using, for example, a bearing. The part attachment area is the portion to which other parts, such as gears, are attached. Table B-17 Radial Run Out of Outer Surface of Rotary Spline Nut Relative to Spline Support Area (Max.) spline shaft total length greater than or less , 1, 1, 1, 1,6 1,6 2, spline shaft SPR 6, * Contact NB for spline shafts exceeding 2. * SPR6 spline shaft Max. length : 4 SPR, Max.length : 15 rotary spline nut Table B-15 Tolerance of Spline Shaft Groove Torsion (Max.) accuracy grade high m/1 The groove torsion is indicated for 1, arbitrarily set as the effective length of the spline section. When the motion length is under 1 or exceeds 1, the value shown in Table B-15 increases or decreases proportionally to the motion length. SPR SPR, * B-33 SPR 2,2A,,A, SPR 4, support area part attachment area Table B- Tolerance of Parts Relative to Spline Support Area(Max.) unit/m part number SPR 6 SPR 8 SPR1 SPR SPR SPR2A SPR2 SPRA SPR SPR3 SPR4 SPR5 SPR6 radial run out of part attachment area perpendicularity of the end of the spline shaft section perpendicularity of the flange SPR unit/m TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT

34 PRE-LOAD AND CLEARANCE IN ROTATIONAL DIRECTION The amount of clearance and pre-load for the spline portion and the cross-roller portion are expressed in terms of the clearance in the rotational direction and the clearance in the radial direction, respectively. Three levels of pre-load are available: standard, light (T1), and medium (T2). Table B-18 Pre-Load and Clearance in Rotational Direction unit/m standard light (T1) medium (T2) SPR SPR 8 SPR1 SPR SPR 8 SPR2A linear motion SPR2 SPRA SPR SPR3 SPR4 SPR SPR6 rotational motion SPR 6 SPR6 5 Table B-19 Operating Condition and Pre-Load pre-load standard light medium symbol blank T1 T2 operating condition Minute vibration is applied. A precise motion is required. Moment is applied in a given direction. Light vibration is applied. Light torsional load is applied. Cyclic torque is applied. Shock/vibration is applied. Over-hang load is applied. Torsional load is applied. SPECIAL REQUIREMENTS NB will fabricate special shaft ends, spline nuts, spline shafts, surface finish etc. to meet customer requirements. Contact NB for details. Figure B-22 Examples of Shaft End Machining Table B-2 recoended hollow shaft part number SPR 6 SPR 8 SPR1 SPR SPR outer dia. inner dia modulus of section giometrical moment of inertia ,26 2,78 d Ds Contact NB for other sizes. B-34

35 SLIDE GUIDE MOUNTING OF The flange attachment bolts have been pre-adjusted for smooth rotary movement and should never be loosened. Shock loading to the flange assembly should be avoided as this can degrade the accuracy of movement and deteriorate the overall performance. Mounting: When the flange is to be used with a faucet joint (as shown in Figure B-23) the housing bore should be machined to a of H7 and to a minimum depth of 6% of the flange thickness. If only a light load is applied to the SPR in operation, the flange can be used without a pilot end. When the mounting bolts are fixed, they should be tightened diagonally in steps with progressively more torque at each step. A torque wrench should be used to achieve uniform torque. The recoended torque values for medium-hardness steel bolts are listed in Table B-21. Insertion of Spline Shaft: When inserting the rotary ball spline shaft into the spline nut, ensure that the ball elements do not drop out. This is accomplished by aligning the raceway grooves of the shaft with the rows of ball elements in the nut. Then simply insert the spline shaft through the spline nut. LUBRICATION B-35 Figure B-23 Flange mounting Method Table B-21 Recoended Torque installation bolt recoended torque (alloy steel bolt) M2.4 M2.5.9 unit/nm Since NB rotary ball splines are equipped with seals at both the spline portion and the rotational portion, the lubricant is retained for an extended period of time. Lithium soap grease is applied prior to shipment, so they can be used iediately without having to apply lubricant. Lubricant should be added periodically and depending on the operating conditions. NB also provides low dust generation grease for the linear system. Please refer to page Eng-2 for details. A grease fitting can be installed as an optional feature however, an oil lubricant should be used for highspeed applications. Contact NB for further details. Figure B-24 Example of Installed Grease Fitting grease fitting M3 1.4 greater than D+(.3 1.) M4 3.2 M M TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT

36 OPERATING ENVIRONMENT Certain operating environments may prevent the full functionality of the rotary ball spline from being achieved expected accuracies. The operating environment should be taken into consideration when designing the system. Operating Temperature: Resin retainers are used in the rotary ball spline, so the operating temperature should never exceed 8. APPLICATION EXAMPLES Dust Prevention: The invasion of foreign particles and dust may affect the motion characteristics of the rotary ball spline and shorten the travel life. Seals will perform well under normal operating conditions, but may not completely prevent the entry of dust in a hostile environment. When used in such environments, a dust prevention mechanism such as bellows or covers should be used to protect the rotary ball spline. ball screw B-36

37 SLIDE GUIDE ball screw TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT B-37 rotary actuator air cylinder

38 SPR TYPE structure example SPR T1-436 / CU SPR type nominal diameter number of nuts attached to one shaft pre-load symbol blank standard T1 light T2 medium with special specification spline shaft total length ball spline major dimensions major dimensions of support bearing part number D1 D2 L P1 S h I H D3 P2 d G m m SPR 6 2 M / SPR 8 SPR1 SPR SPR M2.5 M3 M3 M SPR2A SPR2 SPRA M4 M4 M SPR SPR3 SPR M5 M6 M M SPR5 SPR M8 M B-38

39 SLIDE GUIDE Mo 4-d G depth.4 H (oil hole from back side) D2 D2 Ds Ds L Mo H h I P1 P1 D1 D1 P2 P2 D3 D3 6-d 4-S G depth.4 H (oil hole from back side) SPR61 TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT H I 6-S, depth h spline shaft Ds m / /3 basic torque rating dynamic CT Nm ,39 2,1 ball spline static COT Nm ,18 4,8 L basic load rating dynamic C kn static Co kn support bearing basic load rating dynamic CR kn static COR kn B-39 allowable static moment Mo Nm second crosssectional moment of inertia 4 crosssectional coefficient , Maximum rotational speed for grease lubrication. Contact NB for further information when higher speeds or oil lubrication is required. mass nut spline shaft kg kg/m kN12kgf SPR6 maximum rotational speed rpm 3,5 3,5 3, 1,8 1,5 1,1 1,2 9 1, SPR 6 SPR 8 SPR1 SPR SPR SPR2A SPR2 SPRA SPR SPR3 SPR4 SPR5 SPR6 1Nm.12kgfm

40 The NB stroke ball spine SPLFS type is a high accuracy linear motion bearing with a limited stroke, to which both radial load and torque can be applied at the same time. It operates with extremely small dynamic friction. STRUCTURE AND ADVANTAGES The NB stroke ball spline consists of a nut and a shaft both with raceway grooves. Since the retainer in the nut is equipped with a ball pocket, the steel balls, (rolling elements) do not contact each other, which allows for a smooth linear motion. In a linear motion, however, the retainer moves a half of the travel distance. Therefore, the linear travel stroke is limited up to twice as long as the distance that the retainer can move in the nut. For normal operation, it is recoended to consider 8% of the maximum stroke shown in the dimension list as an actual travel distance. Extremely Small Dynamic Friction and Low Noise: The rolling elements are separated by the ball pockets so that they do not contact each other. The stroke length is limited, but extremely small dynamic friction and low noise are realized because the rolling elements do not circulate. Compact-Size: With the nut about 2% smaller than existing ball splines, it contributes to space saving. All Stainless Steel: Since all the components are made of stainless steel, this stroke ball spline has an excellent corrosion resistance and heat resistance (operating temperature: -2 to +14). It is ideal for clean-room or vacuum applications. Lubrication: A lubricant groove and two lubrication holes are provided on the outer surface of the nut, which allow for an easy designing of lubricant replenishment. Figure B- Structure of SPLFS Type side-ring spline shaft outer cylinder steel ball retainer B-4

41 SLIDE GUIDE ACCURACY The accuracy of the NB stroke ball spline is measured as shown in the figure below. Figure B-26 Accuracy support area part attachment area A-B A-B spline nut Spline Shaft/Groove Distortion Tolerance (Maximum) Groove distortion is measured at a given 1 out of the effective length of the spline portion. When the travel distance is less or more than 1, increase or decrease the value shown in Table B-22 in proportion to the travel distance. A B-41 A-B spline shaft A-B B support area part attachment area Remarks: The support area refers to a portion that supports the spline shaft and to which a bearing is attached. The part attachment area refers to a portion to which another mechanical element, such as a gear, is attached. Table B-23 Tolerance of Parts Relative to Spline Support Area (Max.) SPLFS 6 SPLFS 8 SPLFS1 SPLFS SPLFS radial run out of part attachment area A-B A-B Table B-22 Spline Shaft/Groove Distortion Tolerance (Maximum) (m) Table B-24 Radial Run-Out of Outer Surface of Spline Nut Relative to Spline Support Area (Max.) spline shaft total length greater than or less SPLFS6, * 4 5 3* , 1, 1, 1, 1,5 * maximum fabrication length of SPLFS6: 4 perpendicularity of the end of the spline shaft section SPLFS perpendicularity of the flange SPLFS, unit/m unit/m TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT

42 PRE-LOAD AND CLEARANCE IN ROTATIONAL DIRECTION Both the clearance and pre-load are expressed in terms of clearance in the rotational direction. For the SPLFS type, only the standard value shown below is available. Contact us if you need a clearance other than shown in Table B-. Table B- Pre-Load and Clearance in Rotational Direction unit/m SPLFS 6 SPLFS 8 SPLFS1 SPLFS SPLFS standard COMPARISON OF DYNAMIC FRICTION RESISTANCE Figure B-27 Comparison Data of dynamic Friction Resistance dynamic friction resistance (N) standard pre-load; without load; without lubricant; measuring speed: 2.5 /s SSPA SPLFS travel distance () B-42

43 SLIDE GUIDE NOTES ON USE Dust Control: Since the stroke ball splines are designed and manufactured for operating with an extremely small dynamic friction resistance, any seal that increases the dynamic friction resistance is not equipped as a standard feature. If you use this type of spline under unfavorable conditions, contact us and a special seal will be available.be For use under extremely unfavorable conditions, the stroke ball spline should be protected using bellows and protective covers. Retainer Misalignment: If the stroke ball spline is used at a high speed or with a vertical shaft, or under an asyetric load or oscillation, a retainer misalignment may occur. For general operation, it is recoended to consider 8% of the maximum stroke length shown in the dimension list as a travel distance. In order to prevent the retainer misalignment, it is also recoended to conduct a full-stroke moving operation times during use so that the retainer will be relocated to the center. TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT B-43

44 SPLFS TYPE - Two Side Cut Flange Type - structure example SPLFS CU - / SPLFS type M2 nominal diameter number of nuts attached to one shaft total length of the spline shaft with special specification When two spline nuts are used in close contact major dimensions part number maximum stroke D D1 L E Df H B P.C.D. A F N1-S m SPLFS 6 SPLFS 8 SPLFS1 SPLFS SPLFS B-44

45 SLIDE GUIDE N1-S N1-S B B 2-d F (oil hole) A SPLFS, SPLFS1 SPLFS6 8 Df P.C.D. D1 Ds E H W M1 L 2-d (oil hole) mounting surface TOPBALL PRODUCTS SLIDE BUSH SLIDE UNIT W d Ds m 6 / basic torque rating dynamic static CT COT Nm Nm basic load rating dynamic static C kn Co kn allowable static moment M1 M2 Nm Nm second crosssectional moment mounting surface mass nut shaft g kg/m size N12kgf Nm.12kgfm B-45