Needle Roller Bearings - Ntn-snr.com

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Bearing Fits NTN 7. Bearing Fits 6.1 Interference For rolling bearings, the inner ring and outer ring are fixed on the shaft or in the housing so that relative movement does not occur between the fitted surfaces of the bearing ring and the shaft or housing in radial, axial and rotational directions when a load acts on the bearing. Such a relative movement, if occurred, would result in wear, fretting corrosion, friction crack, etc. on the fitted surfaces, which would then cause damage of the bearing and the shaft or the housing. Furthermore, wear powder invades into the bearing, then causing imperfect rotation, abnormal overheat, vibration, etc. The most effective way to fix a bearing is to assign an proper interference to the fitted surfaces between the bearing ring and the shaft or the housing and to thereby apply "tight fit" to the bearing. Furthermore, as its advantage this tight fit method supports the thin-walled bearing ring with uniform load throughout its entire circumference without any loss of load carrying capacity. The needle roller bearing is a bearing type enabling to separate the inner ring and the outer ring from one another and, therefore, it can be installed on a shaft or in a housing with an interference applied to both of its inner ring and outer ring. In the case of "tight fit", the easiness of bearing installation and removal is lost and, therefore, the bearing ring subjected to stationary load can be "loose-fitted". 6.2 Necessity of proper fit Improper fit could lead to damage and shorter life of bearing. Therefore, advance careful analysis is needed for selection of proper fit. Representative examples of bearing defects caused by improper fit are as described below. ¡Crack and earlier separation of bearing ring, and displacement of bearing ring ¡Wear of bearing ring, shaft and housing caused by creep and fretting corrosion ¡Seizure (sticking) caused by less internal clearance ¡Insufficient running accuracy and abnormal noise caused by deformed raceway surface 6.3 Fit selection Fit selection is generally done in accordance with the rule specified hereunder. The loads acting on each bearing ring are divided into running load, stationary load and directionally unstable load according to the direction and characteristic of loads acting on the bearing. "Tight fit" can be selected for a bearing ring subjected to running load and directionally unstable load and "stationary fit" or "loose fit" be selected for a bearing ring subjected to stationary load. (See Table 6.1) Where load of high magnitude or vibration and shock loads act on a bearing or a light alloy/plastic housing is used, it is necessary to secure a large interference. In that case, however, the housing rigidity must be considered carefully so as not allow occurrence of split damage, etc. For an application subjected to high running accuracy, bearings of high accuracy must be used with a shaft and a housing of higher dimensional accuracy so as not to apply a large interference thereto. Applying a large interference would cause the shaft or housing profile to be transferred to the bearing track, which could then interfere with the bearing running accuracy. The said bearings of high accuracy are used to prevent such possible phenomena. Table 6.1 Radial load and bearing fit Bearing running conditions Sketch Load characteristic Bearing fit Inner ring Outer ring Inner ring : Rotation Outer ring: static Load direction: constant Inner ring: static Outer ring: rotation Load direction: rotating with outer ring Rotating inner ring load Static outer ring load Tight fit Loose fit acceptable, too Inner ring: static Outer ring: rotation Load direction: constant Inner ring: rotation Outer ring: static Load direction : rotating with inner ring Inner ring: rotation or static Outer ring: rotation or static Load direction: The direction can not be fixed. Rotating inner ring load Static outer ring load Loose fit acceptable, too Tight fit Load direction is non-constant due to directional fluctuation, unbalanced load, etc. Directionally unstable load Tight fit Tight fit A-32
Bearing Fits NTN 6.4 Recommended Fits The dimensional tolerances for the diameter of a shaft and the hole diameter of a bearing housing, on/in which a bearing is installed, are standardized under the metric system in ISO 286 and JIS B 0401 (Dimensional Tolerances and Bearing Fits). Hence, bearing fits is determined by selection of the dimensional tolerances for shaft diameter and hole diameter as applicable. Fig. 6.1 shows the relationship between shaft diameter and bearing bore diameter and between housing hole diameter and bearing outer diameter. Table 6.2 shows the recommended fits for the machined ring needle roller bearings (with inner ring) that are generally selected based on the dimensional and load conditions. Table 6.3 shows the numerical fit values. For the recommended fits for others than the machined ring needle roller bearings, refer to "Commentary" described in the respective Dimension Tables. 50m 0 50m f6 g5 g6 h5 h6 js5 js6 k5 n6 p6 k6 m5 m6 dmp 50m 50m 0 F6 F7 G7 G6 H6 Dmp H7 JS6 JS7 K6 K7 M6 M7 N6 N7 P6 P7 R7 Fig. 6.1 (a) Bearing fits on shaft Fig.6.1(b) Bearing fits in housing hole Table 6.2 Machined ring needle roller bearing fits Table 6.2 (1) Dimensional tolerance for shaft diameter Table 6.2 (2) Dimensional tolerances for housing Conditions Load characteristic Load magnitude Shaft diameter d mm Light load 50 50 Rotating inner ring Ordinary load 50150 load or directionally unstable load 150 Heavy load and 150 shock load 150 Inner ring static load Medium- and low-speed rotation, light load General application When high rotational accuracy is required All dimensions Tolerance range class j5 k5 m5 m6 m6 n6 g6 h6 h5 Conditions Tolerance range class Outer ring static load Ordinary and heavy load J7 Two-split housing, ordinary load H7 Rotating outer ring load Directionally unstable load Light load Ordinary load Heavy load and shock load Light load Ordinary load Heavy load and shock load M7 N7 P7 J7 K7 M7 When high rotational accuracy under light load is required K6 Remarks: Light load, ordinary load and heavy load are classified per the following criteria. Light load : Pr0.06Cr Ordinary load : 0.06Cr< Pr0.12Cr Heavy load : Pr>0.12Cr A-33
Page 1 and 2: For New Technology Network R corpor
Page 3 and 4: Technical Data A-001058 Needle roll
Page 5 and 6: Needle Roller Bearings
Page 7 and 8: DIMENSIONAL DATA CONTENTS Needle Ro
Page 9 and 10: Classification and Characteristics
Page 19 and 20: Load Rating and Life NTN Table 2.1
Page 21 and 22: Load Rating and Life NTN When the o
Page 23 and 24: Load Rating and Life NTN 2.10 Radia
Page 25 and 26: Calculation of Bearing Loads NTN (2
Page 27 and 28: Calculation of Bearing Loads NTN 3.
Page 29 and 30: Bearing Accuracy NTN 4. Bearing Acc
Page 31 and 32: A-27 Bearing Accuracy NTN 7 7 8 8 8
Page 33 and 34: Bearing Accuracy NTN Table 4.5 Allo
Page 35: Bearing Internal Clearance NTN 5.2.
Page 39 and 40: Bearing Fits NTN 6.5 Interference C
Page 41 and 42: Shaft Bearing and Fits Housing Desi
Page 43 and 44: Shaft Bearing and Fits Housing Desi
Page 45 and 46: Lubrication NTN Table 8.2 Grease va
Page 47 and 48: Lubrication NTN (4) Circulating lub
Page 49 and 50: Sealing Devices NTN 9. Sealing Devi
Page 51 and 52: Sealing Devices NTN 9.2 Combined se
Page 53 and 54: Bearing Handling NTN 10. Bearing Ha
Page 55 and 56: Bearing Handling NTN the bearing fi
Page 57 and 58: Technical Data NTN 11.2 Bearings wi
Page 59 and 60: Technical Data NTN expressed in the
Page 61 and 62: Bearing Type Symbols and Auxiliary
Page 63 and 64: Needle roller and cage assemblies B
Page 65 and 66: Needle Roller and Cage Assemblies
Page 67 and 68: Needle roller and cage assemblies N
Page 81 and 82: Cage and roller type needle roller
Page 83 and 84: Needle Roller and Cage Assemblies f
Page 85 and 86: Needle roller and cage assemblies f
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Needle roller and cage assemblies f
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Needle roller and cage assemblies f
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Drawn Cup Needle Roller Bearings
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Drawn cup needle roller bearings NT
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Drawn cup needle roller bearings se
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Drawn cup needle roller bearings se
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Machined Ring Needle Roller Bearing
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Machined ring needle roller bearing
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Machined-ring needle roller bearing
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Machined Ring Needle Roller Bearing
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Inner Rings
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Inner rings NTN Type IR d 510mm Bou
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Inner rings NTN d 1520mm Boundary d
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Inner rings NTN d 80100mm Boundary
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Inner rings NTN d 170380mm Boundary
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Inner rings NTN Inch series Type MI
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Inner rings NTN d 101.600203.200mm
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Adjustable-Clearance Needle Roller
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Clearance-adjustable needle roller
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Clearance-adjustable needle roller
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Complex Bearings
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Complex bearings NTN Bearing compon
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Complex bearings NTN B-143
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Needle roller bearings with thrust
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Needle roller bearings with angular
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Needle roller bearings with three-p
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Needle roller bearings with double-
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Needle roller bearings with double-
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Roller Followers / Cam Followers
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Roller followers: Yoke-type track r
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Roller followers : Yoke type truck
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Cam followers stud type truck rolle
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Thrust Roller Bearings
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Thrust roller bearings NTN Bearing
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Thrust roller bearings NTN B-209
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Thrust needle roller bearings NTN B
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Thrust needle roller bearings NTN B
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Thrust cylindrical roller bearing N
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COMPONENTS Needle Rollers/Snap Ring
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Needle rollers NTN Application of n
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Needle rollers NTN DW 4.55mm Bounda
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Snap rings NTN For shaft Type WR Be
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Snap rings NTN For housing Type BR
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Snap rings NTN Bearing numbers Boun
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Seals NTN Type G Type GD Type G Typ
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LINEAR BALL BEARINGS: Solid, Drawn
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Linear Ball Bearings NTN Components
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Linear Ball Bearings NTN Components
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Solid type linear ball bearings NTN
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Machined cup linear ball bearings N
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Linear ball bearings, stroke type N
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Machined ring linear ball bearings
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Linear flat rollers NTN Stopper Fig
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Linear flat rollers NTN Type BF Typ
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Linear roller bearings NTN Type RLM
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One-way Clutches Tension Pulleys, B
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One-way clutches NTN Shaft and hous
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One-way clutch miniature type NTN T
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Bottom roller bearings NTN Type FRI
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Bottom roller bearings NTN Type FRI
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Tensioner pulleys for textile machi
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Contents of Appendix Approximate co
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Appendix NTN ˚C-˚F temperature co
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C-5 Appendix NTN Standard ball Hult
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Appendix NTN Unit system Quantity P
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Appendix NTN Viscosity conversion t
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Appendix NTN Ordinary tolerance for
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Appendix NTN High Low Hig
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Appendix NTN H7 H8 H9 H10 H11 H13 J
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Needle Roller Bearings - Ntn-snr.com

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