Precision Ball Screw/Spline Rotary-Nut Series Linear Motion + Rotary Motion BNS/NS CATALOG No.7E
Contents
Rotary-Nut Series Precision Ball Screw/Spline BNS/NS Japanese patent No. 7 (model NS), 77 (model BNS) Seal Shim plate Outer ring Seal Spline nut Seal Shim plate Seal End cap Ball Retainer Outer ring Shaft Collar Retainer Ball Outer ring Ball screw nut Outer ring Structure of Precision Ball Screw/Spline Structure of Support Bearing Model BNS-A Structure of Support Bearing Model BNS Structure and Features The Ball Screw/Spline is a linear-rotary unit that contains Ball Screw grooves and Ball Spline grooves crossing with each other on a single shaft. The nuts of the Ball Screw and the Ball Spline have dedicated support bearings directly embedded on the circumference of the nuts. The Ball Screw/Spline is capable of performing three (rotary, linear and spiral) modes of motion with a single shaft by rotating or stopping the ball screw nut or the spline nut. It is optimal for machines using a combination of rotary and linear motions, such as a SCARA robot s Z-axis, assembly robot, automatic loader, and machining center s ATC equipment. Zero Axial Clearance The Ball Spline has an angular-contact structure that causes no backlash in the rotational direction, enabling highly accurate positioning. Lightweight and Compact Since the ball screw nut is integrated with the support bearing, highly accurate and compact design is allowed. In addition, small inertia through the lightweight ball screw nut ensures high responsiveness. Smooth Motion with Low Noise As the Ball Screw is based on an end-cap mechanism, smooth motion with low noise is achieved. Highly Rigid Support Bearing The support bearing on the Ball Screw has a contact angle of in the axial direction while that on the Ball Spline has a contact angle of in the moment direction, thus provide a highly rigid shaft support. In addition, a dedicated rubber seal is attached as standard to prevent entry of foreign material. Easy Installation The ball spline nut is designed so that balls do not fall off even if the spline nut is removed from the shaft, thus making installation easy. The Ball Screw/Spline can easily be mounted simply by securing it to the housing with bolts (for the housing s inner- tolerance, H7 is recommended).
Types Model BNS-A [compact type: linear motion + rotary motion] Model BNS [heavy-load type: linear motion + rotary motion] Model NS-A [compact type: linear motion] Model NS [heavy-load type: linear motion]
BNS/NS OUTLINE Product Overview Static Safety Factor It is necessary to take into account a static safety factor indicated in Table 1 against the axial load that is applied on the Ball Screw. When studying the static safety factor, a basic static load rating Ca is required. Ball Screw Unit [Basic Static Load Rating Ca] When a Ball Screw receives an excessive load or a large impact load while it is stationary or in motion, a local permanent deformation occurs between the raceway and the steel ball. If the permanent deformation exceeds a certain limit, it will prevent the Ball Screw from smoothly moving. It is recognized that in general there will be no operational problem if the amount of permanent deformation is up to approximately.1 of the steel ball. The load present in such cases is called basic static load rating Ca. [Static Safety Factor] fs Ca Fa fs : Static safety factor (see Table 1) Ca : Basic static load rating (kn) (see the corresponding dimensional table) Fa : Axial load (kn) Table 1 Static Safety Factor Machine using the Ball Screw Load conditions Lower limit of fs General industrial machinery Machine tools Without vibrations or impact With vibrations or impact Without vibrations or impact With vibrations or impact 1. to 1.. to. 1. to 1.5.5 to 7. Ball Spline Unit [Basic Static Load Rating C] When a Ball Spline receives an excessive load or a large impact load while it is stationary or in motion, a local permanent deformation occurs between the raceway and the rolling element. If the permanent deformation exceeds a certain limit, it will prevent the Ball Spline from smoothly moving. The basic static load rating is a static load with a constant direction and magnitude whereby the sum of the permanent deformation of the rolling element and that of the raceway on the contact area under the maximum stress is.1 times the rolling element. With the Ball Spline, it is defined in terms of radial load. Therefore, the basic static load rating is considered to be the limit of the static permissible load rating. [Static Safety Factor fs] When the Ball Spline is stationary or in motion, an unexpected external force may be applied through inertia caused by vibrations, impact or start/stop. It is necessary to take into account a static safety factor against such a working load. A static safety factor (fs) of a Ball Spline is expressed in how many times greater is the load capacity (basic static load rating C) than the load applied on the Ball Spline. fs C P fs : Static safety factor C : Basic static load rating (N) P : Calculated load (N)
Rated Life and Service Life Time Ball Screw Unit [Basic Dynamic Load Rating Ca] Basic dynamic load rating Ca is used to calculate the service life of a Ball Screw in motion with its ball screw nut being under a load. The basic dynamic load rating Ca is an axial load under which the rated life of % of a group of the same Ball Screw units independently operating is 1 rev (1 million revolutions). [Rated Life] The service life of a Ball Screw is obtained from the equation below using the basic dynamic load rating and the axial load. Ca L = ( ) 1 fw Fa L : Rated life (rev) Ca : Basic dynamic load rating (N) (see the corresponding dimensional table) Fa : Axial load (N) fw : Load factor (see Table ) Table Load Factor Vibrations/impact Velocity (V) fw Faint Weak Medium Strong Very low V. m/s Low.V1. m/s Moderate 1.V. m/s High. m/sv 1. to 1. 1. to 1.5 1.5 to.. to.5 [Service Life Time] When the rated life (L) has been determined, the service life time is obtained from the following equation if the stroke length and the number of reciprocations are constant. Lh = L R Rs n1 Ball Spline Unit ft fc CT L = ( ) 5 fw TC [Service Life Time] When the rated life (L) has been determined, the service life time is obtained if the stroke length and the number of oscillations are constant. (For details, see the General Catalog.) Lh : Service life time (h) Rs : Stroke length (mm) n1 : Revolutions per minute (min -1 ) R : Lead (mm) [Rated Life When a Torque is Applied] [Rated Life When a Radial Load is Applied] ft fc C L = ( ) 5 Lh = fw PC L 1 RS n1 L : Rated life (km) CT : Basic dynamic torque rating (N m) TC : Calculated load torque (N m) C : Basic dynamic load rating (N) PC : Calculated radial load (N) ft : Temperature factor (see the General Catalog) fc : Contact factor (see the General Catalog) fw : Load factor (see the General Catalog) Lh : Service life time (h) RS : Stroke length (m) n1 : Oscillations per minute (opm) (For details, see the General Catalog.)
BNS/NS OUTLINE Product Overview Accuracy The Ball Screw/Spline is manufactured with the following specifications. Ball Screw Unit Axial clearance : or below Lead accuracy : C5 (For details of the specification values, see the General Catalog.) Ball Spline Unit Clearance in the rotational direction : or below (CL: light preload) Accuracy : class H (For details of the specification values, see the General Catalog.) Spline nut Ball screw nut Spline nut Ball screw nut Model BNS Model NS Unit: mm Model No. C D E F H I BNS 1 NS 1 BNS 5 NS 5 BNS 11 NS 11 BNS NS BNS NS BNS NS BNS 44 NS 44 BNS 55 NS 55.14.14.1.1.1.1...17.17.1.1.1.1...14.14.1.1.1.1.1.1.1.1...4.4...1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1
Action Patterns Basic Actions of Model BNS Ball screw nut Ball screw nut pulley: Spline nut Shaft Spline nut pulley: N R: ball screw lead (mm) : ball screw nut rotation speed (min -1 ) N: spline nut rotation speed (min -1 ) Input Shaft motion Motion Action direction Ball Screw pulley Ball Spline pulley Vertical direction (speed) Rotational direction (rotation speed) 1. Vertical Vertical direction downward Rotational direction (Forward) VR () Vertical direction upward Rotational direction (Reverse) VR (). Rotational Vertical direction Rotational direction forward N (Forward) N (Forward) (N) Vertical direction Rotational direction reverse N (Reverse) N (Reverse) (N). Spiral Vertical direction upward Rotational direction forward N (N) VNR N (Forward) Vertical direction downward Rotational direction reverse N (N) VNR N (Reverse)
BNS/NS OUTLINE Product Overview Basic Actions of Model NS Ball screw nut Ball screw nut pulley: Spline nut Shaft R: ball screw lead (mm) : ball screw nut rotation speed (min -1 ) Input Shaft motion Motion Action direction Ball Screw pulley Vertical direction (speed) 1. Vertical Vertical direction downward (Forward) VR () Vertical direction upward (Reverse) VR ()
Extended Actions of Model BNS Input Shaft motion Motion Action direction Ball Screw pulley Ball Spline pulley Vertical direction (speed) Rotational direction (rotation speed) 1. Upward downward forward upward downward reverse Vertical direction upward Vertical direction downward Rotational direction forward (Reverse) (Forward) N (Forward) VR () VR () N (Forward) (N) Vertical direction upward Vertical direction downward Rotational direction reverse N (Reverse) VR () VR () N (Reverse) (N). Downward upward forward downward upward reverse Vertical direction downward Vertical direction upward VR () VR () Rotational direction forward N N (N) Vertical direction downward Vertical direction upward Rotational direction reverse N VR () VR () N (N). Downward forward upward reverse Vertical direction downward VR () Rotational direction forward N N (N) Vertical direction upward VR () Rotational direction reverse N N (N) 4. Downward upward forward reverse Vertical direction downward Vertical direction upward VR () VR () Rotational direction reverse N N (N) Rotational direction forward N N (N)
BNS/NS OUTLINE Product Overview Examples of Installation [Example of Installing Model BNS] Seal Pulley Support bearing Ball screw nut Shaft Support bearing Spline nut Seal Pulley Example of installing the ball screw nut input pulley and the spline nut input pulley, both outside the housing. The housing length is minimized. Pulley Example of installing the ball screw nut pulley inside the housing. [Example of Installing Model NS] Example of installing the ball screw nut pulley outside the housing. The housing length is minimized. Pulley Example of installing the ball screw nut pulley inside the housing. Example of Use Example of Using Model BNS (Z Axis of a SCARA Robot) Ball screw input motor Shaft Pulley Ball screw nut Chuck Stroke Spline input motor Support bearing Pulley Spline nut Stroke
BNS-A TYPE Dimensional Table for Model BNS-A Compact Type: Linear Motion + Rotary Motion equidistant) equidistant) equidistant) equidistant) Model No. BNS 1A BNS 5A BNS 11A BNS A BNS A BNS A BNS 44A Screw Screw shaft outer shaft inner d dp 1 1 14 1 4 Lead Ph 1 15 1 4 Basic load rating Ca Ca 1.1 1.7..1.1 1 1.4 1..7 7. 1. 1.. 4.7 Ball centerto-center dp.4 1.5 1.5.75. 41.75 Thread minor dc.. 1.7 17.5. 5. Outer D g 5 7 1 Flange D1 44 4 7 1 1 Ball screw dimensions Overall length L1 D h7 D4 H7.5 4 7 5 7.5 1 47 7 Model No. BNS 1A BNS 5A BNS 11A BNS A BNS A BNS A BNS 44A Basic load rating C C 1.5.7 7.1 1. 15..5 7.. 4. 1. 17.. 4.5 Static permissible moment MA Nm 5. 15.7 7. 1 7 Basic torque rating CT Nm. 1.4 5. 15 1 41 CT Nm. 7. 4. 55. 1 157 77 Outer D7 g 5 7 1 Flange D5 44 4 7 1 1 Overall length L 5 71 1 Ball spline dimensions D h7 4 5 7.5 BE1 1 1 1 5 4 5 4 BNSA +5L Model number Overall shaft length (in mm)
equidistant) equidistant) equidistant) equidistant) Unit: mm BE 1 47 7 H 7 1 B4 1.5 1.5 1 1 B5 7 1 1 14 1.5 Te 1.5 1.5.5 P1 4 5 4 75 P 1 1 1 1 S M. M M4 M5 M M M t 1.5 1.5 1.5 1 d1.4.4 5.5. Support bearing basic load rating Ca Ca...7.7 1.7 1. 1.5.5.7 1.5 1.4 1... Nut inertial moment kgcm...5.5.1 5.4 17. Screw shaft inertial moment J kgcm /mm.1 1-5 7.71 1-5. 1-4.7 1-4. 1-5. 1-1.4 1 - H1 7 1 B 1.5 1.5 1 1 B7 1 1 1 17 H P 4 5 4 75 P4 1 44 54 S1t1 M. M 4 M4 M5 M5 M 1 M 1 ds1.4.4 5.5. Support bearing basic load rating C C...7 7.4.7 1.5 1.5...4 7. 1. 1.5.7 Nut inertial moment kgcm...44.. 5.17 1.1
BNS TYPE Dimensional Table for Model BNS Heavy-load Type: Linear Motion + Rotary Motion equidistant) Model No. BNS 11 BNS BNS BNS BNS 44 BNS 55 Screw Screw shaft outer shaft inner d dp 1 14 1 4 5 Lead Ph 1 4 5 Basic load rating Ca Ca..1.1 1 1.4 1. 7. 1. 1.. 4.7 77. Ball centerto-center dp 1.5.75. 41.75 5. Thread minor dc 1.7 17.5. 5. 44.1 Outer D 5 7 1.7.7.7.7.. Flange D1 7 15 14 15 Ball screw dimensions Overall length L1 54 5 1 D h7 4 5 1 Model No. BNS 11 BNS BNS BNS BNS 44 BNS 55 Basic load rating C C 7.1 1. 15..5 7.. 1. 17.. 4.5 Static permissible moment MA Nm 7. 1 7 14 Basic torque rating CT Nm 1.4 5. 15 1 41 4 CT Nm 4. 55. 1 157 77 7 Outer 5 5 1 1 D7.7.7.7.7.. Ball spline dimensions Flange D5 7 7 15 1 15 Overall length L 5 71 1 1 Dimension U indicates the length from the head of the hexagon socket bolt to the ball screw nut end face. BNS +L Model number Overall shaft length (in mm)
equidistant) Unit: mm D4 H7 47 7 H 5 1 B4 7.5 4 4 55 B5 1.5 14 1.5 Te 4 P1 7 1 1 1 1 P 1 1 75 S M4 M5 M M M M1 t 1 1 1 1 d1 5.5. 4 4 4 4 5 5 Support bearing basic load rating Ca Ca 1.4.. 5.. 1... 74.1 Nut inertial moment kgcm. 1.44..74 7.. Screw shaft inertial moment J kgcm /mm. 1-4.7 1-4. 1-5. 1-1.4 1 -.5 1 - D h7.5 5 5.5 7.5.5 H1 5 1 B 7 55 74 7 B7 1 1 1 17 P 4 7 1 1 P4 45 55 5 S1t1 M5 M5 M M 1 M 1 M1 15 ds1. U 5 7 1 1 1 Support bearing basic load rating C C 1.7 1. 17..1 7. 41.. 15.5 1 4 4.5 54.1 Nut inertial moment kgcm.5.7 1.7 5.1 14.7.5
NS-A TYPE Dimensional Table for Model NS-A Compact Type: Linear Motion equidistant) equidistant) equidistant) equidistant) Model No. NS 1A NS 5A NS 11A NS A NS A NS A NS 44A Screw Screw shaft outer shaft inner d dp 1 1 14 1 4 Lead Ph 1 15 1 4 Basic load rating Ca Ca 1.1 1.7..1.1 1 1.4 1..7 7. 1. 1.. 4.7 Ball centerto-center dp.4 1.5 1.5.75. 41.75 Thread minor dc.. 1.7 17.5. 5. Outer D g 5 7 1 Flange D1 44 4 7 1 1 Ball screw dimensions Overall length L1 D h7 D4 H7.5 4 7 5 7.5 1 47 7 Model No. NS 1A NS 5A NS 11A NS A NS A NS A NS 44A Basic load rating C C kn kn 1.5. 7.1 1. 15..5 7.. 4. 1. 17.. 4.5 Static permissible moment MA Nm 5. 15.7 7. 1 7 Basic torque rating CT Nm. 1.4 5. 15 1 41 CT Nm. 7. 4. 55. 1 157 77 Ball spline dimensions Flange Outer 1 1 1 5 4 4 4 D7..1.1.1.1.1.1 D5-. 4 51 5 77 1 NSA +5L Model number Overall shaft length (in mm)
equidistant) equidistant) Unit: mm BE 1 47 7 H 7 1 B4 1.5 1.5 1 1 B5 7 1 1 14 1.5 Te 1.5 1.5.5 P1 4 5 4 75 P 1 1 1 1 S M. M M4 M5 M M M t 1.5 1.5 1.5 1 d1.4.4 5.5. Support bearing basic load rating Ca Ca...7.7 1.7 1. 1.5.5.7 1.5 1.4 1... Nut inertial moment kgcm...5.5.1 5.4 17. Screw shaft inertial moment J kgcm /mm.1 1-5 7.71 1-5. 1-4.7 1-4. 1-5. 1-1.4 1 - Overall length 5 71 1 L..... H1 5 7 1 14 B 7.5 1.5 1.5.5 r.5.5.5.5.5.5.5 Greasing hole d 1.5 1.5 4 P 4 4 45 5 ds1.4 5.5 5.5. Mounting hole d.5.5.5 14 h. 4.4 4.4 5.4 5.4.5.
NS TYPE Dimensional Table for Model NS Heavy-load Type: Linear Motion ( equidistant) Model No. NS 11 NS NS NS NS 44 NS 55 Screw Screw shaft outer shaft inner d dp 1 14 1 4 5 Lead Ph 1 4 5 Basic load rating Ca Ca..1.1 1 1.4 1. 7. 1. 1.. 4.7 77. Ball centerto-center dp 1.5.75. 41.75 5. Thread minor dc 1.7 17.5. 5. 44.1 Outer D 5 7 1.7.7.7.7.. Flange D1 7 15 14 15 Ball screw dimensions Overall length L1 54 5 1 D h7 4 5 1 Model No. NS 11 NS NS NS NS 44 NS 55 Basic load rating C C kn kn 7.1 1. 15..5 7.. 1. 17.. 4.5 Static permissible moment MA Nm 7. 1 7 14 Basic torque rating CT Nm 1.4 5. 15 1 41 4 CT Nm 4. 55. 1 157 77 7 Ball spline dimensions Outer 1 5 4 4 4 D7.1.1.1.1.1.1 NS +L Model number Overall shaft length (in mm)
equidistant) Unit: mm D4 H7 47 7 H 5 1 B4 7.5 4 4 55 B5 1.5 14 1.5 Te 4 P1 7 1 1 1 1 P 1 1 75 S M4 M5 M M M M1 t 1 1 1 1 d1 5.5. 4 4 4 4 5 5 Support bearing basic load rating Ca Ca 1.4.. 5.. 1... 74.1 Nut inertial moment kgcm. 1.44..74 7.. Screw shaft inertial moment J kgcm /mm. 1-4.7 1-4. 1-5. 1-1.4 1 -.5 1 - Flange Overall length Greasing hole Mounting hole 51 5 77 1 14 5 71 1 1 L...... H1 7 1 14 1 B 1.5.5 4.5 r.5.5.5.5.5 1 d 4 4 P 4 45 5 1 ds1 5.5 5.5. d.5.5 14 17.5 h 4.4 5.4 5.4.5.
Precautions on Handling LM Guide, Ball Cage, Precision Ball Screw/Spline Models BNS/NS Precautions on Use Disassembling components may cause dust to enter the system or degrade the mounting accuracy of the components. Do not disassemble the components. Tilting the shaft and the ball screw nut (or spline nut) may cause them to fall by their own weight. Dropping or hitting the Precision Ball Screw/Spline may damage or fracture the ball circulation component, which may cause functional loss. Giving an impact to the product could also cause damage to its function even if the product looks intact. Greasing plate Grease nipple Lubrication Thoroughly remove anti-corrosion oil and feed a lubricant before using the product. Do not mix lubricants of different physical properties. In locations exposed to constant vibrations or in special environments, such as clean rooms, vacuum and low/high temperature, normal lubricants may not be used. Contact THK for details. When planning to use a special lubricant, contact THK before using it. Lubrication interval varies according to the service conditions. Contact THK for details. When lubricating the Precision Ball Screw/Spline, attach a greasing plate to the housing in advance (see the figure on the right). Housing Precautions on Use Lubrication Method Do not remove the ball screw nut (or spline nut) from the shaft. Doing so may cause the balls to fall off. Entry of foreign material to the ball screw nut (or spline nut) may cause damage to the ball circulation component or functional loss. Prevent foreign material, such as dust or cutting chips, from entering the system. If foreign material adheres to the product, replenish the lubricant after cleaning the product. For the type of the detergent, contact THK. When planning to use the product in an environment where the coolant penetrates the ball screw nut (or spline nut), it may cause trouble to product functions depending on the type of the coolant. Contact THK for details. Do not use the product at temperature of C or higher. When desiring to use the system at temperature of C or higher, contact THK in advance. If using the product with vertical mount, the ball screw nut (or spline nut) may fall by its own weight. Attach a mechanism to prevent it from falling. Using the product at speed exceeding the permissible rotation speed may cause breakage of a component or accident. Be sure to use the product within the specification range designated by THK. Forcibly driving in a component may cause an indentation on the raceway. Use care when mounting components. If an offset or skewing occurs with the ball screw shaft support and the ball screw nut (or spline nut), it may substantially shorten the service life. Pay much attention to components to be mounted and to the mounting accuracy. When using the product in locations exposed to constant vibrations or in special environments such as clean rooms, vacuum and low/high temperature, contact THK in advance. Letting the ball screw nut (or spline nut) overshoot will cause balls to fall off or the ball circulation component to be damaged. Be sure not to let it overshoot. Storage When storing the Precision Ball Screw/Spline, enclose it in a package designated by THK and store it in a horizontal orientation while avoiding high temperature, low temperature and high humidity., and QZ are registered trademarks of THK CO., LTD. The photo may differ slightly in appearance from the actual product. The appearance and specifications of the product are subject to change without notice. Contact THK before placing an order. Although great care has been taken in the production of this catalog, THK will not take any responsibility for damage resulting from typographical errors or omissions. For the export of our products or technologies and for the sale for exports, THK in principle complies with the foreign exchange law and the Foreign Exchange and Foreign Trade Control Law as well as other relevant laws. All rights reserved For export of THK products as single items, contact THK in advance. 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