Roller Follower General Catalog

Transcription

1 General Catalog A Product Descriptions Features and Types... A20-2 Features of the... A20-2 Structure and Features... A20-2 Types of the... A20-3 Types and Features... A20-4 Point of Selection... A20-6 Nominal Life... A20-6 Accuracy Standards... A20-7 Track Load Capacity... A20-8 Radial Clearance... A20-8 Dimensional Drawing, Dimensional Table Models NAST (Separable Type with a Cylindrical Outer Ring), NAST-R (Separable Type with a Spherical Outer Ring)... A20-10 Models NAST-ZZ (Separable Type with a Cylindrical Outer Ring and Side Plates), NAST-ZZR (Separable Type with a Spherical Outer Ring and Side Plates).. A20-11 Models RNAST (Separable Type with a Cylindrical Outer Ring and No Inner Ring), RNAST-R (Separable Type with a Spherical Outer Ring and No Inner Ring). A20-12 Models NART-R (Non-separable Type with a Spherical Outer Ring), NART-VR (Non-separable Type with a Spherical Outer Ring and Full Balls). A20-13 B Support Book (Separate) Features and Types... B20-2 Features of the... B20-2 Structure and Features... B20-2 Types of the... B20-3 Types and Features... B20-4 Point of Selection... B20-6 Nominal Life... B20-6 Track Load Capacity... B20-8 Example of Calculating a Track Load Capacity... B20-8 Mounting Procedure and Maintenance.. B20-9 Installation... B20-9 Contamination Protection and Lubrication.. B20-9 Model No.... B20-10 Model Number Coding... B20-10 Types and Model Numbers of the.. B20-11 Precautions on Use... B20-12 Point of Design... A20-14 Fit... A20-14 Mounting Section... A20-14 Model No.... A20-15 Model Number Coding... A20-15 Types and Model Numbers of the.. A20-16 Precautions on Use... A20-17 A

2 Features and Types Features of the Outer ring Side plate Inner ring Seal Needle roller Cage Fig.1 Structure of Model NAST-ZZUU Structure and Features The is a compact and highly rigid bearing system. It contains needle bearings and is used as a guide roller for cam discs and straight motion. Since its outer ring rotates while keeping direct contact with the mating surface, this product is thickwalled and designed to bear an impact load. Inside the outer ring, needle rollers and a precision cage are incorporated. This prevents the product from skewing and achieves a superb rotation performance. And, as a result, the product is capable of easily withstanding high-speed rotation. s are divided into two types: separable type whose inner ring can be separated, and non-separable type whose inner ring cannot be separated. There are two types of the outer ring in shape: spherical and cylindrical. The spherical outer ring easily absorbs a distortion of the shaft center when the cam follower is installed and helps lighten a biased load. The is used in a wide range of applications such as cam mechanisms of automatic machines, dedicated machines as well as carrier systems, conveyors, bookbinding machines, tool changers of machining centers, pallet changers, automatic coating machines, and sliding forks of automatic warehouses. A

3 Types of the Features and Types Types of the Separable Type Non-separable Type Standard Type Model NAST Standard Type Model NART-R Standard Type Model NAST-R Full-roller Type Model NART-VR Type with Side Plate Model NAST-ZZ Type with Side Plate Model NAST-ZZR Type without Inner Ring Model RNAST Type without Inner Ring Model RNAST-R A

4 Types of the Types and Features Model NAST (Separable Type) Model NAST is a separable type of bearing system that combines a thick-wall outer ring, an inner ring and needle rollers equipped with a precision cage. Specification Table A Model NAST Model NAST-R (Separable Type) This model is a spherical outer ring type of model NAST. Since the circumference of the outer ring is spherically ground, it helps lighten a biased load (symbol R). Specification Table A Model NAST-R Model NAST-ZZ (Separable Type) This separable type of bearing system has a labyrinth seal consisting of a pair of side plates formed on both sides of the inner ring of model NAST. (Model number of the type attached with seals is NAST-ZZUU.) Specification Table A Model NAST-ZZ Model NAST- ZZR (Separable Type) This model is a spherical outer ring type of model NAST-ZZ. It easily corrects a distortion of the shaft center when the roller follower is installed. Since the circumference of the outer ring is spherically ground, it helps lighten a biased load (symbol R). (Model number of the type attached with seals is NAST-ZZUUR.) Specification Table A Model NAST-ZZR A

5 Features and Types Types of the Model RNAST (Separable Type) This model is basically the same as model NAST, but does not have an inner ring. Specification Table A Model RNAST Model RNAST-R (Separable Type) This model is basically the same as model NAST-R, but does not have an inner ring. Since the circumference of the outer ring is spherically ground, it helps lighten a biased load (symbol R). Specification Table A Model RNAST-R Model NART-R(Non-separable Type) This model is a non-separable type of bearing system whose inner ring is fixed to the side plates. Since the circumference of the outer ring is spherically ground, it helps lighten a biased load (symbol R). (Model number of the type attached with seals is NART-UUR.) Model NART-VR (Non-separable Type) Based on model NART-R, this model is a fullroller bearing suitable for locations where a heavy load is applied in low speed operation. Since the circumference of the outer ring is spherically ground, it helps lighten a biased load (symbol R). (Model number of the type attached with seals is NART-UUVR.) Specification Table A Model NART-R Specification Table A Model NART-VR Stainless steel types are available for all the above models. (symbol M) A

6 Point of Selection Nominal Life Static Safety Factor The basic static load rating C 0 refers to the static load with constant direction and magnitude, under which the calculated contact stress in the center of the contact area between the roller and the raceway under the maximum load is 4000 MPa. (If the contact stress exceeds this level, it will affect the rotation.) This value is indicated as C 0 in the specifi cation tables. When a load is statically or dynamically applied, it is necessary to consider the static safety factor as shown below. C0 P0 fs f S : Static safety factor (see Table1 ) C 0 : Basic static load rating (kn) P 0 : Radial load (kn) Table1 Static Safety Factor (f S ) Load conditions Lower limit of f S Normal load 1 to 3 Impact load 3 to 5 Nominal Life The service life of the is obtained from the following equation. L ft C fw PC L : Nominal life (The total number of revolutions that 90% of a group of identical units independently operating under the same conditions can achieve without showing fl aking from rolling fatigue) C : Basic dynamic load rating (kn) P c : Radial load (kn) f T : Temperature factor (see Fig.1 on A ) f W : Load factor (see Table2 on A ) The basic dynamic load rating (C) of the shows the load with interlocked direction and magnitude, under which the nominal life (L) is 1 million revolutions when a group of identical units independently operate. The basic dynamic load rating (C) is indicated in the corresponding specifi cation table. A

7 Point of Selection Accuracy Standards Calculating the Service Life Time When the nominal life (L) has been obtained, the service life time (L h ) is obtained from the following equation. For Linear Motion Lh 2 D π L n1 ls 60 L h : Service life time (h) L : Nominal life D : Bearing outer diameter (mm) l S : Stroke length (mm) n 1 : Number of reciprocations per minute (min -1 ) For Rotary Motion Lh D 1 n D L D1 n 60 : Outer ring contact average diameter of the cam (mm) : Rotation speed per minute of the cam (min -1 ) Accuracy Standards s are manufactured with accuracies in accordance with the following. (1) Dimensional tolerance of the spherical outer 0 ring in outer diameter D: 0.05 (2) Dimensional tolerance of model RNAST in inscribed bore diameter dr: F6 (3) Dimensional tolerance of model NART in bearing width B: Table3 (4) Accuracy of the inner ring and accuracy of the outer ring in width: Table4 (5) Accuracy of the outer ring: Table5 Temperature factor ft Temperature of the bearing unit ( ) Fig.1 Temperature Factor (f T ) Note) The normal service temperature is 80 or below. If the product is to be used at a higher temperature, contact THK. Table2 Load Factor (f W ) Service condition f W Smooth motion without impact 1 to 1.2 Normal motion 1.2 to 1.5 Motion with severe impact 1.5 to 3 Table3 Dimensional tolerance of model NART in bearing width B Model No. Dimensional tolerance (h12) NART Upper limit Lower limit 5 to to to Table4 Accuracy of the Inner Ring and Accuracy of the Outer Ring in Width (JIS Class 0) Unit: m Nominal dimension of the bearing inner diameter (di) (mm) Tolerance of the bearing in outer diameter (dm) (note) Tolerance of the inner ring (or outer ring) in width Above Or less Upper Lower Upper Lower Tolerance of the inner ring in radial runout (max) Note) dm represents the arithmetic average of the maximum and minimum diameters obtained in measuring the bearing inner diameter at two points. Table5 Accuracy of the Outer Ring (JIS Class 0) Unit: m Nominal dimension of the bearing outer diameter (D) (mm) Tolerance of the bearing in outer diameter (Dm) (note) Above Or less Upper Lower Tolerance of the outer ring in radial runout (max) Note) Dm represents the arithmetic average of the maximum and minimum diameters obtained in measuring the bearing outer diameter at two points. A

8 Track Load Capacity Track load capacity refers to the permissible load which the outer ring of the roller follower and its mating surface material can withstand given repeated use over a long period. The track load capacity provided in the specification table, indicates the value when using a steel material with tensile strength of 1.2 kn/ mm 2 as the mating material. Therefore, it is possible to increase the track load capacity by increasing the hardness of the material. Fig.2 shows the hardness of the mating material and the track capacity factor in relation to tensile strength. To obtain the track load capacity of each mating material, multiply the track load capacity shown in the corresponding specifi cation table by the respective track load factor. Note) For the mating material, we recommend using those materials with the raceway hardness of 20 HRC or higher and the tensile strength of 755 N/mm 2 or higher. Track capacity factor Track capacity factor Spherical outer ring Cylindrical outer ring Raceway surface hardness [HRC] Tensile strength (N/mm 2 ) Fig.2 Track Capacity Factor Radial Clearance The radial clearances of caged type s are based on the values indicated in the tables below (both full-roller type and caged type of model NART share the same radial clearance). Model NAST, NAST-ZZ Unit: m Model No. Radial clearance (with cage) Min. Max to to to to Model NART Unit: m Radial clearance Model No. (caged type and full-roller type) Min. Max. 5 to to to to to A

9 Point of Selection Track Load Capacity A

10 Models NAST (Separable Type with a Cylindrical Outer Ring), NAST-R (Separable Type with a Spherical Outer Ring) r B C r1 φ φ D di φ dr r1 r Model NAST R500 Model NAST-R Model No. Main dimensions Basic load rating Unit: mm Track load capacity Rotational Mass speed Cylindrical Spherical limit outer ring outer ring Inner Inscribed Outer C C 0 diameter bore diameter diameter di dr D B C r smin r 1smin kn kn kn kn min 1 g NAST NAST NAST NAST NAST NAST NAST NAST NAST NAST NAST NAST NAST Note) The rotation speed limit value in the table ( ) applies to models using grease lubrication. With those models using oil lubrication, up to 130% of this value is permitted. Stainless steel types are also available. Contact THK for details. A

11 Models NAST-ZZ (Separable Type with a Cylindrical Outer Ring and Side Plates), NAST-ZZR (Separable Type with a Spherical Outer Ring and Side Plates) B C φ d1 e2 e1 e1 e2 φ D φ di φ a R500 R500 Model NAST-ZZ Model NAST-ZZUU Model NAST-ZZR Model NAST-ZZUUR Model No. Main dimensions Basic load rating Unit: mm Track load capacity Rotational Mass speed Cylindrical Spherical limit outer ring outer ring Inner Outer Oil C C 0 diameter diameter hole di D B C a e 1 e 2 d 1 kn kn kn kn min 1 g NAST 6ZZ NAST 8ZZ NAST 10ZZ NAST 12ZZ NAST 15ZZ NAST 17ZZ NAST 20ZZ NAST 25ZZ NAST 30ZZ NAST 35ZZ NAST 40ZZ NAST 45ZZ NAST 50ZZ Note) The rotation speed limit value in the table ( ) applies to models that have no seal and use grease lubrication. With those models using oil lubrication, up to 130% of this value is permitted. With those attached with seals, up to 70% of this value is permitted. Stainless steel types are also available. Contact THK for details. The seal must be used at temperature of 80 or below. Model number coding NAST 25 ZZ UU R With seal A

12 Models RNAST (Separable Type with a Cylindrical Outer Ring and No Inner Ring), RNAST-R (Separable Type with a Spherical Outer Ring and No Inner Ring) r C φ D φ dr r R500 Model No. Model RNAST Model RNAST-R Unit: mm Main dimensions Basic load rating Track load capacity Rotational Mass speed Inscribed Outer Cylindrical Spherical limit C C 0 bore diameter diameter outer ring outer ring dr D C r smin kn kn kn kn min 1 g RNAST RNAST RNAST RNAST RNAST RNAST RNAST RNAST RNAST RNAST RNAST RNAST RNAST RNAST Note) The rotation speed limit value in the table ( ) applies to models using grease lubrication. With those models using oil lubrication, up to 130% of this value is permitted. Stainless steel types are also available. Contact THK for details. A

13 Models NART-R (Non-separable Type with a Spherical Outer Ring), NART-VR (Non-separable Type with a Spherical Outer Ring and Full Rollers) B C φ d1 φ D r r φ φ di a R500 (model NART17 or lower) R1000 (model NART20 or higher) R500 (model NART17 or lower) R1000 (model NART20 or higher) R500 (model NART17 or lower) R1000 (model NART20 or higher) R500 (model NART17 or lower) R1000 (model NART20 or higher) Model NART-R Model NART-UUR Model NART-VR Model NART-UUVR Model No. Inner Outer diameter diameter Main dimensions Oil hole di D B C a r smin d 1 Track load Basic load rating capacity With Full rollers Spherical cage outer ring C kn C 0 kn C kn C 0 kn Unit: mm Rotational Mass speed limit With Full With cage rollers cage Full rollers kn min 1 min 1 g g NART 5R NART 6R NART 8R NART 10R NART 12R NART 15R NART 17R NART 20R NART 25R NART 30R NART 35R NART 40R NART 45R NART 50R Note) The rotation speed limit value in the table ( ) applies to models that have no seal and use grease lubrication. With those models using oil lubrication, up to 130% of this value is permitted. With those attached with seals, up to 70% of this value is permitted. Stainless steel types are also available. Contact THK for details. The seal must be used at temperature of 80 or below. Model number coding NART 15 UU V R With seal A

14 Point of Design Fit For the fi tting of the with the shaft, we recommend the combinations indicated in Table1. No Inner Ring Table1 Fitting with the Shaft Inner Ring k5, k6 g6, h6 Mounting Section To protect the side plate of models NART and NAST-ZZ, the diameter of the mounting section contacting the side plate must be equal to or greater than the a dimension indicated in the specification table. The structure of the is designed to receive a radial load. If it receives a thrust load, the side plates or the outer ring may be damaged. Therefore, it is necessary to design the system and install the product so that thrust loads are limited to a minimum. If the outer ring moves in the thrust direction, it may contact the mounted part. This can generate abrasive dust and cause wear. To avoid such occurrence, the mounted part shape and specifi cations shown below are recommended. 0.3 or more Thrust washer, etc φ a φ a Direction of thrust Thrust washer, etc. Model NAST-ZZ Model NAST Model RNAST The surface hardness of the shaft to be used with a without inner ring must be between 54 and 64 HRC. For the surface roughness, we recommend 0.2 m Ra or below. For the mating raceway, see Track Load Capacity on A. If the outer ring unilaterally or unevenly contacts the mating raceway, we recommend using a type whose outer ring circumference is spherically ground. The side plate of model NART is press-fi t onto the inner ring. If the plate is pressed under an external force, it may cause abnormal rotation. Do not use the product in the manner that the side plate is pressed. A

15 Model No. Model Number Coding Model number confi gurations differ depending on the model features. Refer to the corresponding sample model number confi guration. Models NAST, NAST-R, NAST-ZZ, NAST-ZZR, RNAST, RNAST-R, NART-R and NART-VR NAST 25 M ZZ UU R No Symbol: Carbon steel (standard) M: Stainless steel With seal A

16 Types and Model Numbers of the The is divided into several types as indicated in Table1. Classification Standard Type Table1 Types of Separable type Type with side plate Type without inner ring Non-separable Type Standard Type Full-roller Type Main model No. NAST NAST-ZZ RNAST NART Shape Cylindrical outer ring Spherical outer ring Full rollers Without seal NAST NAST-M With seal Without seal NAST-R NAST-MR With seal NAST-ZZ NAST-MZZ NAST-ZZUU NAST-MZZUU NAST-ZZR NAST-MZZR NAST-ZZUUR NAST-MZZUUR RNAST RNAST-M RNAST-R RNAST-MR Without seal With seal NART-R NART-MR NART-UUR NART-MUUR NART-VR NART-MVR NART-UUVR NART-MUUVR Note: Symbol M indicates stainless steel type. A

17 Precautions on Use Handling (1) Do not disassemble the parts. This will result in loss of functionality. (2) Take care not to drop or strike the. Doing so may cause injury or damage. Giving an impact to it could also cause damage to its function even if the product looks intact. (3) When handling the product, wear protective gloves, safety shoes, etc., as necessary to ensure safety. Precautions on Use (1) Do not use the product at temperature of 80 or higher. Exposure to higher temperatures may cause the resin/rubber parts to deform/be damaged. (2) Prevent foreign material, such as cutting chips or coolant, from entering the system. Failure to do so may cause damage. (3) If foreign material such as cutting chips adheres to the product, replenish the lubricant after cleaning the product. (4) s are designed for use under a radial load. Do not use the product under a thrust load. (5) Micro-oscillation makes it diffi cult for oil film to form on the raceway in contact with the rolling element, and may lead to fretting. Accordingly, use grease offering excellent fretting toughness. It is also recommended that the Cam Follower be turned once or so on a regular basis to make sure oil film is formed between the raceway and rolling element. (6) Insufficient rigidity or accuracy of mounting members causes the bearing load to concentrate on one point and the bearing performance will drop signifi cantly. Accordingly, give sufficient consideration to the rigidity/accuracy of the housing and base and strength of the fi xing bolts. Lubrication (1) Some types of the do not contain grease depending on the model number. Carefully refer to B, and if the desired model does not contain grease, apply grease to the product as necessary before using it. Lithium soap-based grease No. 2 is available as standard. (2) Do not mix different lubricants. In addition, replenish a lubricant also during operation as necessary. Mixing greases using the same type of thickening agent may still cause adverse interaction between the two greases if they use different additives, etc. (3) We recommend applying a lubricant to the mating surface where the travels. (4) When using the product in locations exposed to constant vibrations or in special environments such as clean rooms, vacuum and low/high temperature, use the grease appropriate for the specifi cation/environment. (5) The consistency of grease changes according to the temperature. Take note that the slide resistance of the also changes as the consistency of grease changes. (6) After lubrication, the slide resistance of the may increase due to the agitation resistance of grease. Be sure to perform a break-in to let the grease spread fully, before operating the machine. (7) Excess grease may scatter immediately after lubrication, so wipe off scattered grease as necessary. (8) The properties of grease deteriorate and its lubrication performance drops over time, so grease must be checked and added properly according to the use frequency of the machine. (9) The greasing interval varies depending on the use condition and service environment. Set the final lubrication interval/amount based on the actual machine. A

18 Storage When storing the, enclose it in a package designated by THK and store it in a room while avoiding high temperature, low temperature and high humidity. After the product has been in storage for an extended period of time, lubricant inside may have deteriorated, so add new lubricant before use. Disposal Dispose of the product properly as industrial waste. A

19 General Catalog B Support Book Features and Types... B20-2 Features of the... B20-2 Structure and Features... B20-2 Types of the... B20-3 Types and Features... B20-4 Point of Selection... B20-6 Nominal Life... B20-6 Track Load Capacity... B20-8 Example of Calculating a Track Load Capacity... B20-8 Mounting Procedure and Maintenance.. B20-9 Installation... B20-9 Contamination Protection and Lubrication.. B20-9 Model No.... B20-10 Model Number Coding... B20-10 Types and Model Numbers of the.. B20-11 Precautions on Use... B20-12 A Product Descriptions (Separate) Features and Types... A20-2 Features of the... A20-2 Structure and Features... A20-2 Types of the... A20-3 Types and Features... A20-4 Point of Selection... A20-6 Nominal Life... A20-6 Accuracy Standards... A20-7 Track Load Capacity... A20-8 Radial Clearance... A20-8 Dimensional Drawing, Dimensional Table Models NAST (Separable Type with a Cylindrical Outer Ring), NAST-R (Separable Type with a Spherical Outer Ring)... A20-10 Models NAST-ZZ (Separable Type with a Cylindrical Outer Ring and Side Plates), NAST-ZZR (Separable Type with a Spherical Outer Ring and Side Plates).. A20-11 Models RNAST (Separable Type with a Cylindrical Outer Ring and No Inner Ring), RNAST-R (Separable Type with a Spherical Outer Ring and No Inner Ring). A20-12 Models NART-R (Non-separable Type with a Spherical Outer Ring), NART-VR (Non-separable Type with a Spherical Outer Ring and Full Balls). A20-13 Point of Design... A20-14 Fit... A20-14 Mounting Section... A20-14 Model No.... A20-15 Model Number Coding... A20-15 Types and Model Numbers of the.. A20-16 Precautions on Use... A20-17 B

20 Features and Types Features of the Outer ring Side plate Inner ring Seal Needle roller Cage Fig.1 Structure of Model NAST-ZZUU Structure and Features The is a compact and highly rigid bearing system. It contains needle bearings and is used as a guide roller for cam discs and straight motion. Since its outer ring rotates while keeping direct contact with the mating surface, this product is thickwalled and designed to bear an impact load. Inside the outer ring, needle rollers and a precision cage are incorporated. This prevents the product from skewing and achieves a superb rotation performance. And, as a result, the product is capable of easily withstanding high-speed rotation. s are divided into two types: separable type whose inner ring can be separated, and non-separable type whose inner ring cannot be separated. There are two types of the outer ring in shape: spherical and cylindrical. The spherical outer ring easily absorbs a distortion of the shaft center when the cam follower is installed and helps lighten a biased load. The is used in a wide range of applications such as cam mechanisms of automatic machines, dedicated machines as well as carrier systems, conveyors, bookbinding machines, tool changers of machining centers, pallet changers, automatic coating machines, and sliding forks of automatic warehouses. B

21 Types of the Features and Types Types of the Separable Type Non-separable Type Standard Type Model NAST Standard Type Model NART-R Standard Type Model NAST-R Full-roller Type Model NART-VR Type with Side Plate Model NAST-ZZ Type with Side Plate Model NAST-ZZR Type without Inner Ring Model RNAST Type without Inner Ring Model RNAST-R B

22 Types of the Types and Features Model NAST (Separable Type) Model NAST is a separable type of bearing system that combines a thick-wall outer ring, an inner ring and needle rollers equipped with a precision cage. Specification Table A Model NAST Model NAST-R (Separable Type) This model is a spherical outer ring type of model NAST. Since the circumference of the outer ring is spherically ground, it helps lighten a biased load (symbol R). Specification Table A Model NAST-R Model NAST-ZZ (Separable Type) This separable type of bearing system has a labyrinth seal consisting of a pair of side plates formed on both sides of the inner ring of model NAST. (Model number of the type attached with seals is NAST-ZZUU.) Specification Table A Model NAST-ZZ Model NAST- ZZR (Separable Type) This model is a spherical outer ring type of model NAST-ZZ. It easily corrects a distortion of the shaft center when the roller follower is installed. Since the circumference of the outer ring is spherically ground, it helps lighten a biased load (symbol R). (Model number of the type attached with seals is NAST-ZZUUR.) Specification Table A Model NAST-ZZR B

23 Features and Types Types of the Model RNAST (Separable Type) This model is basically the same as model NAST, but does not have an inner ring. Specification Table A Model RNAST Model RNAST-R (Separable Type) This model is basically the same as model NAST-R, but does not have an inner ring. Since the circumference of the outer ring is spherically ground, it helps lighten a biased load (symbol R). Specification Table A Model RNAST-R Model NART-R(Non-separable Type) This model is a non-separable type of bearing system whose inner ring is fixed to the side plates. Since the circumference of the outer ring is spherically ground, it helps lighten a biased load (symbol R). (Model number of the type attached with seals is NART-UUR.) Model NART-VR (Non-separable Type) Based on model NART-R, this model is a fullroller bearing suitable for locations where a heavy load is applied in low speed operation. Since the circumference of the outer ring is spherically ground, it helps lighten a biased load (symbol R). (Model number of the type attached with seals is NART-UUVR.) Specification Table A Model NART-R Specification Table A Model NART-VR Stainless steel types are available for all the above models. (symbol M) B

24 Point of Selection Nominal Life Static Safety Factor The basic static load rating C 0 refers to the static load with constant direction and magnitude, under which the calculated contact stress in the center of the contact area between the roller and the raceway under the maximum load is 4000 MPa. (If the contact stress exceeds this level, it will affect the rotation.) This value is indicated as C 0 in the specifi cation tables. When a load is statically or dynamically applied, it is necessary to consider the static safety factor as shown below. C0 P0 fs f S : Static safety factor (see Table1 ) C 0 : Basic static load rating (kn) P 0 : Radial load (kn) Table1 Static Safety Factor (f S ) Load conditions Lower limit of f S Normal load 1 to 3 Impact load 3 to 5 Nominal Life The service life of the is obtained from the following equation. L ft C fw PC L : Nominal life (The total number of revolutions that 90% of a group of identical units independently operating under the same conditions can achieve without showing fl aking from rolling fatigue) C : Basic dynamic load rating (kn) P c : Radial load (kn) f T : Temperature factor (see Fig.1 on B ) f W : Load factor (see Table2 on B ) The basic dynamic load rating (C) of the shows the load with interlocked direction and magnitude, under which the nominal life (L) is 1 million revolutions when a group of identical units independently operate. The basic dynamic load rating (C) is indicated in the corresponding specifi cation table. B

25 Point of Selection Nominal Life Calculating the Service Life Time When the nominal life (L) has been obtained, the service life time (L h ) is obtained from the following equation. For Linear Motion Lh 2 D π L n1 ls 60 L h : Service life time (h) L : Nominal life D : Bearing outer diameter (mm) l S : Stroke length (mm) n 1 : Number of reciprocations per minute (min -1 ) For Rotary Motion Lh D 1 n D L D1 n 60 : Outer ring contact average diameter of the cam (mm) : Rotation speed per minute of the cam (min -1 ) Temperature factor ft Temperature of the bearing unit ( ) Fig.1 Temperature Factor (f T ) Note) The normal service temperature is 80 or below. If the product is to be used at a higher temperature, contact THK. Table2 Load Factor (f W ) Service condition f W Smooth motion without impact 1 to 1.2 Normal motion 1.2 to 1.5 Motion with severe impact 1.5 to 3 B

26 Track Load Capacity Track load capacity refers to the permissible load which the outer ring of the roller follower and its mating surface material can withstand given repeated use over a long period. The track load capacity provided in the specification table, indicates the value when using a steel material with tensile strength of 1.2 kn/ mm 2 as the mating material. Therefore, it is possible to increase the track load capacity by increasing the hardness of the material. Fig.2 shows the hardness of the mating material and the track capacity factor in relation to tensile strength. To obtain the track load capacity of each mating material, multiply the track load capacity shown in the corresponding specifi cation table by the respective track load factor. Note) For the mating material, we recommend using those materials with the raceway hardness of 20 HRC or higher and the tensile strength of 755 N/mm 2 or higher. Example of Calculating a Track Load Capacity Track capacity factor Track capacity factor Spherical outer ring Cylindrical outer ring Raceway surface hardness [HRC] Tensile strength (N/mm 2 ) Fig.2 Track Capacity Factor Obtain the track load capacity when heat-treating the mating material, which a bearing whose outer ring has a track load capacity of 5.29 kn contacts, to hardness of 50 HRC. The track capacity factor when the hardness is 50 HRC is 2.84, as indicated in Fig.2. Therefore, the desired track load capacity is calculated as follows. The track load capacity=5.29kn 2.84=15.0kN B

27 Mounting Procedure and Maintenance Installation Fig.1 shows examples of installing the. If the is to be used under a heavy load, it is necessary to install the product so that the greasing hole of the inner ring is out of the loaded area. Nut Threaded part Model RNAST Model NAST-ZZ Radial load Model NART Thrust load Model NART Model NART Fig.1 Examples of Installing the Note) When mounting model NART, do not secure it with a nut as with model NAST-ZZ shown in the figure above. Doing so may cause the side plate to deform. Contamination Protection and Lubrication The models include seal types (model numbers: UU ), which are incorporated with special synthetic rubber seals that are highly resistant to wear in order to prevent foreign material from entering the interior of the roller follower and the lubricant from leaking. Some models are not filled with grease when assembled. When using a model not filled with grease, apply and fill grease to the interior fi rst (lithium-based grease with consistency of No. 2). NAST(R) RNAST(R) NAST-ZZ(R) NART-(V)R Model No. Grease No seal setting Not fi lled with grease Without seal With seal Filled with grease The lubrication interval varies depending on the operating conditions. As a guide, however, replenish grease of the same group every six months to two years for types with a cage, or every one to six months for full-roller types. Even with types equipped with seals ( UU ), surplus grease may seep during the initial operation period or immediately after resumption of grease replenishment. If desiring to avoid contamination of the surrounding area of the machine by grease, fi rst perform seasoning or the like in advance, and then wipe the seeping surplus grease. B

28 Model No. Model Number Coding Model number confi gurations differ depending on the model features. Refer to the corresponding sample model number configuration. Models NAST, NAST-R, NAST-ZZ, NAST-ZZR, RNAST, RNAST-R, NART-R and NART-VR NAST 25 M ZZ UU R No Symbol: Carbon steel (standard) M: Stainless steel With seal B

29 Model No. Types and Model Numbers of the The is divided into several types as indicated in Table1. Classification Standard Type Table1 Types of Separable type Type with side plate Type without inner ring Non-separable Type Standard Type Full-roller Type Main model No. NAST NAST-ZZ RNAST NART Shape Cylindrical outer ring Spherical outer ring Full rollers Without seal NAST NAST-M With seal Without seal NAST-R NAST-MR With seal NAST-ZZ NAST-MZZ NAST-ZZUU NAST-MZZUU NAST-ZZR NAST-MZZR NAST-ZZUUR NAST-MZZUUR RNAST RNAST-M RNAST-R RNAST-MR Without seal With seal Note: Symbol M indicates stainless steel type. NART-R NART-MR NART-UUR NART-MUUR NART-VR NART-MVR NART-UUVR NART-MUUVR B

30 Precautions on Use Handling (1) Do not disassemble the parts. This will result in loss of functionality. (2) Take care not to drop or strike the. Doing so may cause injury or damage. Giving an impact to it could also cause damage to its function even if the product looks intact. (3) When handling the product, wear protective gloves, safety shoes, etc., as necessary to ensure safety. Precautions on Use (1) Do not use the product at temperature of 80 or higher. Exposure to higher temperatures may cause the resin/rubber parts to deform/be damaged. (2) Prevent foreign material, such as cutting chips or coolant, from entering the system. Failure to do so may cause damage. (3) If foreign material such as cutting chips adheres to the product, replenish the lubricant after cleaning the product. (4) s are designed for use under a radial load. Do not use the product under a thrust load. (5) Micro-oscillation makes it diffi cult for oil film to form on the raceway in contact with the rolling element, and may lead to fretting. Accordingly, use grease offering excellent fretting toughness. It is also recommended that the Cam Follower be turned once or so on a regular basis to make sure oil film is formed between the raceway and rolling element. (6) Insufficient rigidity or accuracy of mounting members causes the bearing load to concentrate on one point and the bearing performance will drop signifi cantly. Accordingly, give sufficient consideration to the rigidity/accuracy of the housing and base and strength of the fi xing bolts. Lubrication (1) Some types of the do not contain grease depending on the model number. Carefully refer to B, and if the desired model does not contain grease, apply grease to the product as necessary before using it. Lithium soap-based grease No. 2 is available as standard. (2) Do not mix different lubricants. In addition, replenish a lubricant also during operation as necessary. Mixing greases using the same type of thickening agent may still cause adverse interaction between the two greases if they use different additives, etc. (3) We recommend applying a lubricant to the mating surface where the travels. (4) When using the product in locations exposed to constant vibrations or in special environments such as clean rooms, vacuum and low/high temperature, use the grease appropriate for the specifi cation/environment. (5) The consistency of grease changes according to the temperature. Take note that the slide resistance of the also changes as the consistency of grease changes. (6) After lubrication, the slide resistance of the may increase due to the agitation resistance of grease. Be sure to perform a break-in to let the grease spread fully, before operating the machine. (7) Excess grease may scatter immediately after lubrication, so wipe off scattered grease as necessary. (8) The properties of grease deteriorate and its lubrication performance drops over time, so grease must be checked and added properly according to the use frequency of the machine. (9) The greasing interval varies depending on the use condition and service environment. Set the final lubrication interval/amount based on the actual machine. B

31 Storage When storing the, enclose it in a package designated by THK and store it in a room while avoiding high temperature, low temperature and high humidity. After the product has been in storage for an extended period of time, lubricant inside may have deteriorated, so add new lubricant before use. Disposal Dispose of the product properly as industrial waste. Precautions on Use B

32 B 506E