R

Bearing
Technical Calculation Tool
Usage Method

Contents
1-1. Overview of Bearing Technical Calculations………………………………………………… 2

1-2. Screen flowchart …………………………………………………………………………………………… 4
1-3. Bearing technical calculation screen operation ……………………………………………… 5
1−3− 1. Description of on-screen buttons ………………………………………………………………………… 5
1−3− 2. Description of selection items ……………………………………………………………………………… 5
1−3− 3. Description of input items ………………………………………………………………………………… 7
1−3− 4. Description of output items ………………………………………………………………………………… 9
1−3− 5. Description of quantity symbols ………………………………………………………………………… 12
1−3− 6. Technical calculation menu screen ……………………………………………………………………… 13
1−3− 7. Basic rating life …………………………………………………………………………………………… 14
1−3− 8. Gear load and basic rating life …………………………………………………………………………… 18
1−3− 9. Bearing load and basic rating life………………………………………………………………………… 23
1−3−10. Operating clearance calculation ………………………………………………………………………… 27
1−3−11. Bearing vibration frequency ……………………………………………………………………………… 29
1−3−12. Bearing search window …………………………………………………………………………………… 31
1-4. Warning screens …………………………………………………………………………………………… 33
1−4− 1. Basic rating life …………………………………………………………………………………………… 33
1−4− 2. Gear load and basic rating life, bearing load and basic rating life …………………………………… 33
1−4− 3. Operating clearance calculation ………………………………………………………………………… 34
1-5. Error messages …………………………………………………………………………………………… 35
1−5− 1. Basic rating life …………………………………………………………………………………………… 35
1−5− 2. Gear load and basic rating life, bearing load and basic rating life …………………………………… 36
1−5− 3. Operating clearance calculation ………………………………………………………………………… 37
1−5− 4. Bearing vibration frequency ……………………………………………………………………………… 38
1-6. Calculation formula ……………………………………………………………………………………… 40
1−6− 1. Description of quantity symbols ………………………………………………………………………… 40
1−6− 2. Gear load …………………………………………………………………………………………………… 43
1−6− 3. Load distribution on bearings …………………………………………………………………………… 43
1−6− 4. Calculation of equivalent load …………………………………………………………………………… 46
1−6− 5. Calculation of average equivalent load when calculating bearing unit life ………………………… 46
1−6− 6. Calculation of basic rating life …………………………………………………………………………… 47
1−6− 7. Calculation of total life of bearing system ……………………………………………………………… 47
1−6− 8. Total life of the bearing unit calculated from the frequency of meshing conditionsof the gear in 1-3-8. Gear load and basic rating life …………………………………………………… 47
1−6− 9. Calculation of average inner ring groove diameter, average outer ring groove diameter ………… 47
1−6−10. Expansion of each component dimension taking into account shaft and housing temperature … 47
1−6−11. Calculation of inner ring and shaft ……………………………………………………………………… 48
1−6−12. Outer ring and housing calculation ……………………………………………………………………… 49
1−6−13. Calculation of clearance reduction due to temperature difference of shaft and housing ………… 50
1−6−14. Operating clearance calculation ………………………………………………………………………… 50
1−6−15. Calculation of fitting pressure (shaft and bearing), fitting stress (shaft and bearing) ………………50
1−6−16. Calculation of fitting pressure (bearing and housing), fitting stress (outer ring) …………………… 51
1−6−17. Calculation of bearing vibration frequency ……………………………………………………………… 51
1−6−18. Calculation of modified rating life………………………………………………………………………… 52

1-7. Appendix tables……………………………………………………………………………………………56

1／62

NTN

Bearing Technical Calculation Tool Usage Method

1-1. Overview of Bearing Technical Calculations
There are five technical calculations that can be performed within the NTN Bearing Technical Calculation Tool.

1. Basic rating life
(calculation function) ¡Can be input/output in SI units¡Input/output either grease lubrication or oil lubrication¡Bearing basic rating life based on JIS (L10h) or modified rating life that takes into accountaISO (L10mh)(input item)¡Can be selected by entering the boundary dimensions (inner dia., outer dia., width) andsearching for the bearing, or entering the bearing product name¡Selection of the calculated bearing life, lubrication (oil, grease)¡Up to 10 steps can be entered for the load placed on the bearing (radial load, axial load)
and rot. speed¡Required life¡【For modified rating life】In addition to the above, the contamination level or contamination
factor, lubricating oil kinematic viscosity (40°C, 100°C), and operating temperature(output item)¡Basic rating life (L10h), basic dynamic load ratings, basic static load ratings, fatigue limit
load, equivalent load, limiting speed (catalog, adjusted)¡【For modified rating life】In addition to the above, the modified rating life (L10mh),
contamination level or contamination factor, operating temperature, lubricating oil viscosity
during operation, reference kinematic viscosity, viscosity ratio and life modification factor

2. Gear load and basic rating life
(calculation function) ¡Can be input/output in SI units¡Input/output either grease lubrication or oil lubrication¡Applies to 2 shafts¡Bearing supported at two points on the shaft¡Up to five gear meshing conditions¡Bearing basic rating life based on JIS (L10h) or modified rating life that takes into accountaISO (L10mh)(input item)¡Can be selected by entering the boundary dimensions (inner dia., outer dia., width) andsearching for the bearing, or entering the bearing product name¡Distance bet. bearings¡Selection of the calculated bearing life, lubrication (oil, grease)¡Gear specifications¡Input shaft tor.
¡Input shaft rot.
¡【For modified rating life】In addition to the above, the contamination level or contamination
factor, lubricating oil kinematic viscosity (40°C, 100°C), and operating temperature(output item)¡Gear torque of the input shaft and output shaft, rot. speed, and gear load (tangent dir. load,
radial dir. load, axial dir. load) under each condition¡Total life (L10h), brg. system life, basic dynamic load ratings, and fatigue limit load of each bearing¡Bearing load (radial dir. load, axial dir. load), limiting speed (adjusted), rot. speed, equivalentload, basic rating life (L10h), and frequency of each bearing, under each condition¡【For modified rating life】In addition to the above, the modified rating life (L10mh),
contamination level or contamination factor, operating temperature, lubricating oil viscosity
during operation, reference kinematic viscosity, viscosity ratio and life modification factor

3. Bearing load and basic rating life
(calculation function) ¡Can be input/output in SI units¡Input/output either grease lubrication or oil lubrication¡Selection of the calculated bearing life, lubrication (oil, grease)

2／62

NTN

Bearing Technical Calculation Tool Usage Method¡Bearing basic rating life based on JIS (L10h) or modified rating life that takes into accountaISO (L10mh)¡Two bearing rows
¡Up to three load centers(input item)¡Can be selected by entering the boundary dimensions (inner dia., outer dia., width) andsearching for the bearing, or entering the bearing product name¡Distance bet. bearings¡Load conditions (radial load, axial load, moment load, load center position)¡Rot. speed¡【For modified rating life】In addition to the above, the contamination level or contamination
factor, lubricating oil kinematic viscosity (40°C, 100°C), and operating temperature(output item)¡Bearing basic rating life (L10h), brg. system life
¡Bearing load (radial load, axial load), equivalent load, basic dynamic load ratings,
basic static load ratings¡Limiting speed (catalog, adjusted)¡【For modified rating life】In addition to the above, the modified rating life (L10mh),
contamination level or contamination factor, operating temperature, lubricating oil viscosity
during operation, reference kinematic viscosity, viscosity ratio and life modification factor

4. Operating clearance calculation(calculation function) ¡Can be input/output in SI units¡Radial internal clearance taking into account the fit with the shaft and bearing, bearing andhousing, and shaft and housing material and temperature¡Fitting pressure and fitting stress calculation taking into account the fit with the shaft andbearing, bearing and housing, and shaft and housing material and temperature(input item)¡Can be selected by entering the boundary dimensions (inner dia., outer dia., width) andsearching for the bearing, or entering the bearing product name
¡Bearing tolerances¡Radial internal clearance¡Shaft bore diameter, housing outer diameter¡Fit with shaft and housing¡Material of shaft and housing¡Shaft, housing temperature under operating condition(output item)¡Minimum and maximum values of the residual clearance, fitting pressure and fitting stressafter fitting (not taking into account the temperature of the shaft and housing)¡Minimum and maximum values of the operating clearance, fitting pressure and fitting stressunder operating condition (taking into account the temperature of the shaft and housing)

5. Bearing vibration frequency(calculation function) ¡Calculate the bearing vibration frequency generated form within the bearing due to rotationof the bearing(input item)¡Can be selected by entering the boundary dimensions (inner dia., outer dia., width) andsearching for the bearing, or entering the bearing product name¡Rot. speed(output item)¡Rotational speed of cage
¡Rotational speed of cage relative to inner ring
¡Number of load cycles of inner ring per second¡Number of load cycles of outer ring per second¡Rotational speed of rolling element

3／62

NTN

Bearing Technical Calculation Tool Usage Method

1-2. Screen flowchart
On-screen processing for each window is displayed in Fig. 1.

Basic rating life
BearingselectionscreenOperatingcondition
input screen

Bearing life
list display
screenBearing life
details display
screenGear load and basic rating life
BearingselectionscreenGearspecification
input screen

Gear load
display
screenBearingsystem life
display
screenBearing life
details
display
screenBearing load and basic rating life
TOP menu
screenTechnical
calculation
menu screen

BearingselectionscreenOperatingcondition
input screen

Bearingsystem life
display
screenOperating clearance calculation

Input screen

Calculation
results
display
screenBearing vibration frequency
Input output
screenFig. 1. Screen transition between each window

4／62

Bearinglife details
display
screenNTN

Bearing Technical Calculation Tool Usage Method

1-3. Bearing technical calculation screen operation
1-3-1. Description of on-screen buttons
Print ……………………Prints the displayed screen on a printer or similar device.
OK………………………If there is no error, proceed to the next screen. If there is an error, a warning screen is displayed.
Calculate ………………If there is no error, the calculation results screen is displayed. If there is an error, a warning screen
is displayed.
Search …………………Search for bearings from the inner dia., outer dia. and width. (see 1-3-12. Bearing search window)
Bearing A (B, C, D) …The basic rating life (L10h) and the modified rating life (L10mh) are displayed for each condition of
the selected bearing.
Bearing life ……………If there is no problem with use under the operating conditions of the bearing, the total life of the
bearing system and bearing is displayed. If there is a problem with use under the operating
conditions of the bearing, an error message is displayed.
Detail of Brg. life ……The basic rating life (L10h) for each condition of each bearing and the modified rating life (L10mh)
depending on the selection are displayed.
Condition 1 (2, 3, 4, 5) …For 1-3-8. Gear load and basic rating life, the screen switches to one where the gear specificationsof meshing conditions for the selected gear are input.
Detailed display ……The results of the detailed operating life for the selected bearing are displayed.
Main menu ……………Changes to the main menu.
Return …………………Changes to the previous screen.

1-3-2. Description of selection items
Axial load ……………For 1-3-8. Gear load and basic rating life and 1-3-9. Bearing load and basic rating life, when abearing other than the following bearings is selected, click whether or not to apply an axial loadwith the mouse. (the load is applied by default)
Angular contact ball brgs., tapered roller brgs. (metric series), tapered roller brgs. (inch series)
Bearing type …………For 1-3-7. Basic rating life, click the appropriate bearing from the following displayed bearing types
with the mouse.
Deep groove ball brgs., expansion compensating brgs., miniature ball brgs., (metric series),
angular contact ball brgs. (30˚, 40˚), four-point contact ball brgs., double row angular contact ballbrgs., self-aligning ball brgs., cylindrical roller brgs., double row cylindrical roller brgs., tapered
roller brgs. (metric series), tapered roller brgs. (inch series), double row tapered roller brgs.
(outward facing), double row tapered roller brgs. (inward facing), spherical roller brgs., thrust ballbrgs., thrust self-aligning roller brgs.
For 1-3-8. Gear load and basic rating life and 1-3-9. Bearing load and basic rating life, click theappropriate bearing from the following displayed bearing types with the mouse.
Deep groove ball brgs., expansion compensating brgs., miniature ball brgs. (metric series),
angular contact ball brgs. (30˚, 40˚), double row angular contact ball brgs., self-aligning ball brgs.,
cylindrical roller brgs., double row cylindrical roller brgs., tapered roller brgs. (metric series),

5／62

NTN

Bearing Technical Calculation Tool Usage Method

tapered roller brgs. (inch series), double row tapered roller brgs. (outward facing), double row
tapered roller brgs. (inward facing), spherical roller brgs.
For 1-3-10. Operating clearance calculation, click the appropriate bearing from the following
displayed bearing types with the mouse.
Deep groove ball brgs., cylindrical roller brgs. spherical roller brgs.
For 1-3-11. Bearing vibration frequency, click the appropriate bearing from the following displayed
bearing types with the mouse.
Deep groove ball brgs., angular contact ball brgs. (30˚, 40˚), self-aligning ball brgs. cylindricalroller brgs., tapered roller brgs. (metric series), tapered roller brgs. (inch series), spherical roller
brgs.
Bearing tolerances …For 1-3-10. Operating clearance calculation, click the bearing precision to use from JIS Class 0,
JIS Class 6, JIS Class 5, JIS Class 4 and JIS Class 2 with the mouse. (see 1-7. attached tables 1
and 2)
Bearing selection ……For 1-3-8. Gear load and basic rating life and 1-3-9. Bearing load and basic rating life, select thebearing by entering the bearing type and NTN product name.
Shaft material ………For 1-3-10. Operating clearance calculation, click the shaft material to use with the mouse. The
materials that can be selected are as displayed below. (see 1-7. attached tables 14)
Bearing steels, carbon steels, gray iron castings, spheroidal graphite iron castings, aluminium,
martensitic stainless steels, austenitic stainless steels, copper
Fit with shaft …………For 1-3-10. Operating clearance calculation, click the fit symbol of the bearing and shaft to use
with the mouse.
The fit symbols that can be selected are as displayed below. (see 1-7. attached tables 6 to 9)

d6

e6

f6

g5
g6

h5
j5
h6
j6
h7
j7
h8
h9
h10

js5
js6

k5
k6
k7

m5
m6

n6

p6

r6
r7

Housing material ……For 1-3-10. Operating clearance calculation, click the housing material to use with the mouse.
The materials that can be selected are as displayed below. (see 1-7. attached tables 14)
Bearing steels, carbon steels, gray iron castings, spheroidal graphite iron castings, aluminium,
martensitic stainless steels, austenitic stainless steels, copper
Fit with housing ……For 1-3-10. Operating clearance calculation, click the fit with bearing and housing symbol to use
with the mouse.
The fit symbols that can be selected are as displayed below. (see 1-7. attached tables 10 to 13)

E6

F6
F7

G6
G7

H6
H7
H8

J6
J7

JS6
JS7

K5
K6
K7

6／62

M5
M6
M7

N5
N6
N7

P6
P7

NTN

Bearing Technical Calculation Tool Usage Method

Lubrication ……………Click either oil or grease to use with the mouse.
(grease is selected by default)
Contact ang. ort. ……For 1-3-8. Gear load and basic rating life and 1-3-9. Bearing load and basic rating life, when abearing other than the following bearings are selected, click the direction of the contact ang. withthe mouse.
Angular contact ball brgs., tapered roller brgs. (metric series), tapered roller brgs. (inch series)
I/O Param. Unit ………I/O param. unit for load, etc., is SI only.
Input shaft rotation direction ……For 1-3-8. Gear load and basic rating life, click either clockwise or counterclockwise to
use with the mouse. (clockwise is selected by default)
Gear shape A (gear shape B) ……For 1-3-8. Gear load and basic rating life, click the gear to use from spur, helical-rightor helical-left with the mouse.
(spur is selected by default)
Radial internal clearance …………For 1-3-10. Operating clearance calculation, click the bearing radial internal clearance
to use from C2, CN, C3, C4 or C5 with the mouse. (see 1-7. attached tables 3 to 5)

1-3-3. Description of input items
Axial load ……………For 1-3-7. Basic rating life, enter the axial load to be applied to the bearing. (kgf)
For 1-3-9. Bearing load and basic rating life, enter the axial load to be applied to the bearing. (N)Pres. angle ……………For 1-3-8. Gear load and basic rating life, enter the pres. angle of the gear. (˚)
Operating temperature ……………For 1-3-7. Basic rating life, 1-3-8. Gear load and basic rating life, and 1-3-9. Bearing
load and basic rating life, enter the assumed operating temperature when themodified rating life L10mh (taking into account aISO) was selected for the calculated
operating life selection in each of these. If this is not entered, it will automatically be
set to 20°C. (°C)
Shaft temperature under …………For 1-3-10. Operating clearance calculation, enter the temperature of the shaft underoperating condition
operating condition If this is not entered, it will automatically be set to 20˚. (˚C)
Housing temperature ……………For 1-3-10. Operating clearance calculation, enter the temperature of the housing
under operating condition
under operating condition If this is not entered, it will automatically be set to 20˚. (˚C)
NTN product name …Enter the NTN bearing number(for calculations other than 1-3-7. Basic rating life, click the "Search" button if the NTN productname is unknown, and use the 1-3-12 Bearing search window)
Contamination factor ec …………For 1-3-7. Basic rating life, 1-3-8. Gear load and basic rating life, and 1-3-9. Bearing
load and basic rating life, select the contamination level or directly enter the value
was selected for the calculated operating life selection in each of these.
Rot. speed ……………For 1-3-7. Basic rating life, enter the rot. speed of the bearing.
For 1-3-9. Bearing load and basic rating life and 1-3-11. Bearing vibration frequency, enter the rot.
speed of the shaft (inner ring). (min-1)

7／62

NTN

Bearing Technical Calculation Tool Usage Method

Calculated operating life selection …For 1-3-7. Basic rating life, 1-3-8. Gear load and basic rating life, and 1-3-9. Bearing
load and basic rating life, select basic rating life (L10h) or modified rating life (L10mh)
for each of these.
(Basic rating life (L10h) is selected by default.)
Distance bet. effective load………For 1-3-8. Gear load and basic rating life and 1-3-9. Bearing load and basic rating life,
if bearing A and bearing B (bearing C and bearing D) are the bearings displayed
below, enter the distance between the effective load of one bearing and the effective
load of the other bearing. (mm)Angular contact ball brgs., tapered roller brgs. (metric series), tapered roller brgs.
(inch series)
Distance between bearing ………For 1-3-8. Gear load and basic rating life and 1-3-9. Bearing load and bearing basic
A and bearing B
distance rating life, enter the distance between the bearing centers of bearing A and(distance between bearing C
bearing B (bearing C and bearing D). (mm)and bearing D)
Shaft bore diameter …For 1-3-10. Operating clearance calculation, enter the inner dia. of the shaft. If this is not entered,
the calculation will be made as a solid shaft. (mm)Housing outer diameter…For 1-3-10. Operating clearance calculation, enter the outer dia. of the housing. If this is notentered, it will automatically be set to a size 1.3 times the shaft outer dia. (mm)Lubrication ……………For 1-3-7. Basic rating life, 1-3-8. Gear load and basic rating life, and 1-3-9. Bearing load andbasic rating life, select the contamination level or enter the contamination factor directly.
Lubricating oil kinematic viscosity …For 1-3-7. Basic rating life, 1-3-8. Gear load and basic rating life, and 1-3-9. Bearing
load and basic rating life, enter the lubricating oil kinematic viscosity at 40°C and 100°C
for each of these. It is also possible to click and enter any item from the ISO dynamic
viscosity grade table or the grease characteristics table depending on the lubrication.
(mm2/s)Use rate ………………For 1-3-7. Basic rating life, enter the hours or the ratio for performing each step. If there is only
one step, there is no need to enter this. (hours or %)Frequency ……………For 1-3-8. Gear load and basic rating life, enter the frequency of the gear meshing conditions. (%)
Steps …………………For 1-3-7. Basic rating life, enter the number of ways the load conditions and rot. speed change.

Inner dia., outer dia., width ………For 1-3-7. Basic rating life, if the NTN product name is unknown, enter the min or max
of at least the bearing inner dia., bearing outer dia. or bearing width, and search forthe bearing. (mm)In the 1-3-12. Bearing search window, enter the min or max of at least the bearing
inner dia., bearing outer dia. or bearing width, and search for the bearing. (mm)Input shaft rot. ………For 1-3-8. Gear load and basic rating life, enter the rot. speed to be applied to the input shaft.
(min-1)
Input tor. ………………For 1-3-8. Gear load and basic rating life, enter the torque to be applied to the input shaft. (N-mm)
Twisting angle ………For 1-3-8. Gear load and basic rating life, when selecting the helical gear, enter the twisting angleof the gear. (˚)
Gear pos. ……………For 1-3-8. Gear load and basic rating life, enter the distance from the reference bearing to thegear. (mm)

8／62

NTN

Bearing Technical Calculation Tool Usage Method

Teeth …………………For 1-3-8. Gear load and basic rating life, enter the number of gear teeth.
Notes …………………Enter comments related to the calculations. The calculation is not affected even if this is left
empty.
Module…………………For 1-3-8. Gear load and basic rating life, enter the module of gear.
Moment load …………For 1-3-9. Bearing load and basic rating life, enter the moment load to be applied to the shaft.
(N-mm)
Required life …………For 1-3-7. Basic rating life, enter the minimum life required of the bearing. (hours)
Radial load ……………For 1-3-7. Basic rating life, enter the radial load to be applied to the bearing. (N)For 1-3-9. Bearing load and basic rating life, enter the radial load to be applied to the bearing.
(N)

1-3-4. Description of output items
Axial load ……………Axial load placed on the bearing (Fa) (N)Axial dir. load ………For 1-3-8. Gear load and basic rating life, the load generated in the gear axial direction isdisplayed. (N)Operating clearance …For 1-3-10. Operating clearance calculation, fit the bearing on to the shaft and housing, and theradial internal clearance under operating conditions is displayed. (mm)The min and max operating clearance is displayed as there are tolerances with the initial radial
internal clearance, fit with shaft and fit with housing.
NTN product name …Bearing number
Contamination factor…For 1-3-7. Basic rating life, 1-3-8. Gear load and basic rating life, and 1-3-9. Bearing load andbasic rating life, the contamination level and contamination factor are displayed.
Outer dia. ……………Bearing outer dia. (D) (mm)Rot. speed ……………For 1-3-7. Basic rating life and 1-3-11. Bearing vibration frequency, the rot. speed of the bearing isdisplayed. (min-1)
For 1-3-8. Gear load and basic rating life and 1-3-9. Bearing load and basic rating life, the rot.
speed of the bearing is displayed. (min-1)
Number of load cycles of …………For 1-3-11. Bearing vibration frequency, the number of rolling elements that passouter ring per second
through a single point on the outer track surface per second. (Hz)
Reference kinematic viscosity ……Depends on rotation speed n and size (Dpw) of the bearing. (mm2/s)
Basic static load ratings …………Static radial load (static central axial load) (Cor or Coa) (N) corresponding to thecalculated contact stress displayed below at the contact center with the rolling
element and track being subjected to maximum load
Self-aligning ball brgs.: 4600 MPa
Other ball brgs.: 4200 MPa
Roller brgs.: 4000 MPa
The total permanent deformation of the rolling element and track under these contractstresses is approximately 0.0001 times the diameter of the rolling element.

9／62

NTN

Bearing Technical Calculation Tool Usage Method

Basic rating life ………When individual bearings within the same group are rotated under the same conditions, this is theactual total number of rotations that is possible when 90% (90% reliability) of those bearings rotate
without any flaking caused by rolling fatigue is generated. When the bearing is rotated at a fixed
rpm, the total number of hours is used. (hours)
Basic dynamic load ratings ………A certain static radial load (central axial load) (Cr or Ca) (N) that the bearing should
theoretically be able to withstand a basic rating life of 1 million rotations.
Gear torque …………For 1-3-8. Gear load and basic rating life, the torque applied to the gear is displayed. (N-mm)
Limiting speed ………As the rot. speed of the bearing increases, the temperature of the bearing increases due to friction
heat generated within the bearing, which causes burning and other damage, preventing reliable
operation of the bearing from continuing. This limiting rotational speed is called the limiting speed.
(min-1)The "Catalog" is the limiting speed value listed in the "NTN Bll and Roller Bearing Catalog"(CAT.NO.2203/E).
The "Adjusted value" is the value acquired when the adjusted coefficient is applied by applying aload to the "Catalog" value.
Count of result ………For 1-3-7. Basic rating life, this is the number of bearings when (basic rating life) ≥ (required life) is
met.
Residual clearance …For 1-3-10. Operating clearance calculation, the radial internal clearance is displayed with thebearing fit to the shaft and housing. (mm)The min and max residual clearance is displayed as there are tolerances with the initial radial
internal clearance, fit with shaft and fit with housing.
Corrected rating life…The life corrected using the aISO factor that was calculated from the contamination factor,
lubricating oil kinematic viscosity, operating temperature, etc., against the basic rating life L10h.
(hours)Bearing life ……………For 1-3-8. Gear load and basic rating life, the total life of each bearing takes into account thefrequency of gear meshing conditions. (hours)
For 1-3-9. Bearing load and basic rating life, this is the basic rating life (L10h) of each bearing
calculated from the bearing load placed on each bearing. (hours)
Brg. system life ………For 1-3-8. Gear load and basic rating life and 1-3-9. Bearing load and basic rating life, this is thelife for bearing systems that are supported by two bearings until either bearing becomesdamaged due to rolling fatigue. (hours)
Modified rating life …Obtained with the following formula from the basic rating life using the life modification factor
Lnm = a1・aISO・Ln
Life ……………………For 1-3-8. Gear load and basic rating life, this is the basic rating life (L10h) for each meshingcondition of the gear in the Detail of Brg. life window. (hours)
For 1-3-9. Bearing load and basic rating life, this is the basic rating life (L10h) for each bearing in
the Detail of Brg. life window. The value is the same as "Bearing life." (hours)Life modification factor …Obtained by integrating material characteristics and lubrication conditions. It is given as a function
like the following formula in ISO 281:2007.

ec Cu
aISO = f (ーーーpー k )
Lubrication ……………The selected lubrication conditions are displayed. (oil lubrication or grease lubrication)

10／62

NTN

Bearing Technical Calculation Tool Usage Method

Use rate ………………For 1-3-7. Basic rating life, the hours or the ratio for performing each step is displayed. If thenumber of steps is "1" and no use rate is entered, the use rate in the output is displayed as "1."(hours or %)Frequency ……………For 1-3-8. Gear load and basic rating life, the frequency of the gear meshing conditions isdisplayed. (%)
Tangent dir. load ……For 1-3-8. Gear load and basic rating life, the load generated in the gear Tangent dir. is displayed.
(N)
Total life ………………For 1-3-8. Gear load and basic rating life, this is the total life of each bearing taking into accountthe frequency of the meshing condition of the gear in the Detail of Brg. life window. (hours)
For 1-3-9. Bearing load and basic rating life, this is the basic rating life (L10h) for each bearing in
the Detail of Brg. life window. The value is the same as "Bearing life" and "Life." (hours)
Units……………………The selected units are displayed. (SI unit or Gravit. unit)
Rotational speed of …For 1-3-11. Bearing vibration frequency, the rot. speed of the rolling element per second isrolling element
displayed when viewed from the center of the bearing. (Hz)Equivalent load ………A certain static radial load (central axial load) placed on the bearing so that the same life as thelife of bearings achieved under actual load conditions is attained. (Pr or Pa) (N)Inner dia. ………………Bearing inner dia. (d) (mm)Number of load cycles of…For 1-3-11. Bearing vibration frequency, the number of rolling elements that pass through a single
inner ring per second
point on the inner track surface per second. (Hz)
Rotational speed of cage…For 1-3-11. Bearing vibration frequency, this is the rotational speed of the cage per second
relative to inner ring
relative to the standard rotating inner ring. (Hz)
Width …………………Bearing width (B) (mm)Fitting stress …………For 1-3-10. Operating clearance calculation, the stress generated when fitting the shaft and(inner ring)
bearing is displayed. (MPa)The min and max fitting stress is displayed as there are tolerances in fitting with the shaft.
Fitting stress …………For 1-3-10. Operating clearance calculation, the stress generated when fitting the bearing and(outer ring)
housing is displayed. (MPa)The min and max fitting stress is displayed as there are tolerances in fitting with the housing.
Fitting pressure ……For 1-3-10. Operating clearance calculation, the pressure generated when fitting the bearing and(bearing and housing) housing is displayed. (MPa)The min and max fitting pressure is displayed as there are tolerances in fitting with the housing.
Fitting pressure ……For 1-3-10. Operating clearance calculation, the pressure generated when fitting the shaft and(shaft and bearing)
bearing is displayed. (MPa)The min and max fitting pressure is displayed as there are tolerances in fitting with the shaft.
Fatigue limit load ……Load applied on bearings that becomes the fatigue limit stress at the maximum load contact partof the raceway. This depends on the bearing internal specifications, quality, and material strength.
The fatigue limit load values with respect to the NTN bearing numbers are specified in eachspecification table. (N)Rotational speed ……For 1-3-11. Bearing vibration frequency, this is the rot. speed of the cage per second. (Hz)of cage

11／62

NTN

Bearing Technical Calculation Tool Usage Method

Notes …………………Details entered into the notes are displayed as they are.
Required life …………For 1-3-7. Basic rating life, the required life that was entered is displayed. (hours)
Radial load ……………Radial load placed on the bearing (Fr) (N)Radial dir. load ………For 1-3-8. Gear load and basic rating life, the load generated in the gear radial direction isdisplayed. (N)

1-3-5. Description of quantity symbols
B ………Bearing width (mm)C ………Basic dynamic load ratings (N)Ca ………Basic dynamic axial load ratings (N)If the bearing type is four-point contact ball brgs., thrust ball brgs., thrust spherical roller brgs. C＝Ca
Cr ………Basic dynamic radial load ratings (N)If the bearing type is a bearing other than four-point contact ball brgs., thrust ball brgs.,
thrust spherical roller brgs. C＝Cr
Co ………Basic static load ratings (N)Coa ……Basic static axial load ratings (N)If the bearing type is four-point contact ball brgs., thrust ball brgs., thrust spherical roller brgs. Co＝Coa
Cor………Basic static radial load ratings (N)If the bearing type is a bearing other than four-point contact ball brgs., thrust ball brgs.,
thrust spherical roller brgs. Co＝Cor
d…………Bearing inner dia. (mm)D ………Bearing outer dia. (mm)d＋D
dp ………As determined by dp＝———— (mm)2
Fa ………Axial load (N)Fr ………Radial load (N)n ………Rot. speed (min-1)
P ………Equivalent load (N)Pa ………Equivalent axial load (N)If the bearing type is four-point contact ball brgs., thrust ball brgs., thrust spherical roller brgs. P＝Pa
Pr ………Equivalent radial load (N)If the bearing type is a bearing other than four-point contact ball brgs., thrust ball brgs.,
thrust spherical roller brgs. P＝Pr

12／62

NTN

Bearing Technical Calculation Tool Usage Method

1-3-6. Technical calculation menu screen

Screen No. 1 Technical calculation menu window

13／62

NTN

Bearing Technical Calculation Tool Usage Method

1-3-7. Basic rating life
1. Bearing selection

Screen No. 2 Bearing selection window(selection item) (see 1-3-2 Description of selection items)
Life selection, bearing type, lubrication(input item) (see 1-3-3 Description of input items)
Enter the calculation details into the notes if necessary.
If the NTN product name is known
Enter the NTN product name.
If the NTN product name is unknown
Enter at least one of inner dia. (min and max), outer dia. (min and max), and width (min and max).

14／62

NTN

Bearing Technical Calculation Tool Usage Method

2. Enter operating conditions

Screen No. 3 Enter operating conditions(The section in the red box is only for the modified rating life)(input item) (see 1-3-3 Description of input items)
Always enter the number of steps.
Enter the required life if necessary.
Always enter the rot. speed and use rate for each step. For a single step, the use rate does not need to be entered.
Enter the required item for each step for the radial load and axial load.
(When modified rating life was selected) Select the contamination level or select “Direct input” and then directly enter
the contamination factor value. Always enter the lubricating oil kinematic viscosity for 40°C and 100°C. Always enter theoperating temperature. Click the “See index” button to open the “Contamination factor ec index” and confirm the content
of each contamination level. Also, click the “See ISO grade table” button (for oil lubrication) and the “See greasecharacteristics table” button (for grease lubrication) to open a table with typical base oil viscosity for each lubricant.
Click the row in the table to enter the corresponding base oil viscosity value in the column for 40°C and 100°C of the
lubricating oil kinematic viscosity.

15／62

NTN

Bearing Technical Calculation Tool Usage Method

3. Life calculation results display<List display of life>

Screen No. 4 List display of life
(The section in the red box is only for the modified rating life)(output item) (see 1-3-4 Description of output items)
Notes, required life, count of result, units, lubrication, NTN product name, basic dynamic load ratings, equivalent load,
basic rating life (L10h), limiting speed (catalog, adjusted), inner dia., outer dia., width
Note 1) The basic rating life (L10h) is displayed as "9999999.9" if it exceeds 10 million hours.
Note 2) If the count of results exceeds 24, a scroll bar is displayed on the right edge of the screen and the screen canbe moved up and down.
Click "△" with the mouse: move the screen up
Click "▽" with the mouse: move the screen down
(When modified rating life was selected) The contamination factor, lubricating oil kinematic viscosity (40°C, 100°C),
operating temperature, and modified rating life (L10mh).

16／62

NTN

Bearing Technical Calculation Tool Usage Method<Details of life calculation results>

Screen No. 5 Detailed display of life calculation results(The section in the red box is only for the modified rating life)(output item) (see 1-3-4 Description of output items)
Notes, NTN product name, required life, count of result, units, lubrication, step No., radial load, axial load, rot. speed,
use rate, basic dynamic load ratings, basic static load ratings, equivalent load, limiting speed (catalog, adjusted), basic
rating life (L10h).
Note 1) The basic rating life is displayed as "9999999.9" if it exceeds 10 million hours.
(When modified rating life was selected) The modified rating life (L10mh), contamination factor, viscosity ratio, kinematic
viscosity, reference kinematic viscosity, life correction factor.

17／62

NTN

Bearing Technical Calculation Tool Usage Method

1-3-8. Gear load and basic rating life
1. Bearing setting

Screen No. 6 Bearing setting window(The section in the red box is only for the modified rating life)(selection item) (see 1-3-2 Description of selection items)
When the bearing type is angular contact ball brgs. (30˚, 40˚), tapered roller brgs. (metric series), tapered roller brgs.
(inch series)
Bearing selection, bearing type, lubrication, contact ang. ort. and for other bearing types
Bearing selection, bearing type, lubrication, axial load
(input item) (see 1-3-3 Description of input items)
Enter the calculation details into the notes if necessary.
If the NTN product name is known
Enter the NTN product name.
If the NTN product name is unknown
Click the "Search" button and search for the relevant bearing. (see 1-3-12. Bearing search window)
When the bearing type is angular contact ball brgs. (30˚, 40˚), tapered roller brgs. (metric series), tapered roller brgs.
(inch series), enter the distance bet. effective load (bearing A and bearing B, bearing C and bearing D).
For other bearing types,
enter the distance between bearing A and bearing B, and the distance between bearing C and bearing D.
(When modified rating life was selected) Select the contamination level or select “Direct input” and then directly enter
the contamination factor value. Always enter the lubricating oil kinematic viscosity for 40°C and 100°C. Always enter theoperating temperature. Click the “See index” button to open the “Contamination factor ec index” and confirm the content
of each contamination level. Also, click the “See ISO grade table” button (for oil lubrication) and the “See greasecharacteristics table” button (for grease lubrication) to open a table with typical base oil viscosity for each lubricant.
Click the row in the table to enter the corresponding base oil viscosity value in the column for 40°C and 100°C of the
lubricating oil kinematic viscosity.

18／62

NTN

Bearing Technical Calculation Tool Usage Method

2. Enter gear specifications

Screen No. 7 Gear specification input window(button items) (see 1-3-1 Description of on-screen buttons)
Condition 1 (condition 2, condition 3, condition 4, condition 5)(selection item) (see 1-3-2 Description of selection items)
Input shaft rotation direction, gear type A, gear type B(input item) (see 1-3-3 Description of input items)
Input tor., input shaft rot. speed, number of teeth, module, pressure angle
gear position: gear A is the distance from bearing A, gear B is the distance from bearing C(If gear A (B) is to the right of bearing A (C): enter pos.
If gear A (B) is to the left of bearing A (C): enter neg.)
Twisting angle (helical gear only)
The frequency is up to five conditions, and the total of all conditions must be 100%.

19／62

NTN

Bearing Technical Calculation Tool Usage Method

3. Calculation results display<Gear load>

Screen No. 8 Gear load display(output item) (see 1-3-4 Description of output items)
Notes, units, lubrication, gear torque, rot. speed, tangent dir. load, radial dir. load, axial dir. load

20／62

NTN

Bearing Technical Calculation Tool Usage Method<Total life of bearing system and bearings>

Screen No. 9 Display of total life of bearing system and bearings(The section in the red box is only for the modified rating life)(output item) (see 1-3-4 Description of output items)
Notes, units, lubrication, NTN product name, basic dynamic load ratings, bearing life (L10h): Total life of each bearing(hours)Brg. system life: total life of combination of bearing A and bearing B, and bearing C and bearing D (hours)
Note 1) The life is displayed as "9999999.9" if it exceeds 10 million hours.
(When modified rating life was selected) Modified rating life (L10mh): Total life of each bearing (hours)

21／62

NTN

Bearing Technical Calculation Tool Usage Method<Detail of Brg. life>

Screen No. 10 Display of details of bearing life
(The section in the red box is only for the modified rating life)(output item) (see 1-3-4 Description of output items)
Notes, NTN product name, units, lubrication, basic dynamic load ratings, basic static load ratings, limiting speed catalog
value
Total life: total life taking into account the frequency of each bearing (hours)
The output items below are displayed for each condition.
Radial load, axial load, limiting speed adjusted value, rot. speed, equivalent load, life (L10h), frequency.
Note 1) The life is displayed as "9999999.9" if it exceeds 10 million hours.
(When modified rating life was selected) Life (L10mh)

22／62

NTN

Bearing Technical Calculation Tool Usage Method

1-3-9. Bearing load and basic rating life
1. Bearing setting

Screen No. 11 Bearing setting window(The section in the red box is only for the modified rating life)(selection item) (see 1-3-2 Description of selection items)
When the bearing type is angular contact ball brgs. (30˚, 40˚), tapered roller brgs. (metric series), tapered roller brgs.
(inch series), bearing selection, bearing type, lubrication, I/O param. unit, contact ang. ort.
Bearing selection, bearing type, lubrication, contact ang. ort. and for other bearing types
Bearing selection, bearing type, lubrication, axial load
(input item) (see 1-3-3 Description of input items)
Enter the calculation details into the notes if necessary.
If the NTN product name is known
Enter the NTN product name.
If the NTN product name is unknown
Click the "Search" button and search for the relevant bearing. (see 1-3-12. Bearing search window)
When the bearing type is angular contact ball brgs. (30˚, 40˚), tapered roller brgs. (metric series), tapered roller brgs.
(inch series),
Enter the distance bet. effective load a.
For other bearing types,
Enter the distance between bearing A and bearing B.

23／62

NTN

Bearing Technical Calculation Tool Usage Method

2. Enter operating conditions

Screen No. 12 Operating conditions input window(input item) (see 1-3-3 Description of input items)
Always enter the rot. speed.
Enter the radial load (downward: pos., upward: neg.), the axial load (A→B: pos., B→A: neg.), moment load (clockwise:pos., counterclockwise: neg.) placed on each load center into the required items.
Distance from bearing A: distance from bearing A of each load center (mm)(if bearing A is on the left of the load center: neg., if bearing A is on the right of the load center: pos.)Enter the distance from bearing A only for load centers where a load is placed.

24／62

NTN

Bearing Technical Calculation Tool Usage Method

3. Calculation results display<Brg. system life>

Screen No. 13 Display of brg. system life
(The section in the red box is only for the modified rating life)(output item) (see 1-3-4 Description of output items)
Notes, units, lubrication, NTN product name, basic dynamic load rating bearing life: Basic rating life (L10h) of eachbearing (hours)
Brg. system life: life of combination of bearing A and bearing B (hours)
Note 1) The life is displayed as "9999999.9" if it exceeds 10 million hours.
(When modified rating life was selected) Modified rating life (L10mh) of each bearing (hours).

25／62

NTN

Bearing Technical Calculation Tool Usage Method<Detail of Brg. life>

Screen No. 14 Display of details of bearing life
(The section in the red box is only for the modified rating life)(output item) (see 1-3-4 Description of output items)
Notes, units, lubrication, NTN product name, basic dynamic load ratings, basic static load ratings, limiting speed(catalog value, adjusted value), radial load, axial load, rot. speed, equivalent load
Total life: basic rating life of the bearing (hours)
Life: Basic rating life of the bearing (hours) L10h (= total life)(When modified rating life was selected) Life: Modified rating life of the bearing (hours) L10mh
Note 1) The life is displayed as "9999999.9" if it exceeds 10 million hours.

26／62

NTN

Bearing Technical Calculation Tool Usage Method

1-3-10. Operating clearance calculation
1. Enter calculation conditions

Screen No. 15 Bearing setting window(selection item) (see 1-3-2 Description of selection items)
Bearing type, bearing tolerances, radial internal clearance, fit with shaft, shaft material, fit with housing, housingmaterial.
(input item) (see 1-3-3 Description of input items)
Enter the calculation details into the notes if necessary.
If the NTN product name is known
Enter the NTN product name.
If the NTN product name is unknown
Click the "Search" button and search for the relevant bearing. (see 1-3-12. Bearing search window)
Enter the required items for shaft bore diameter, housing outer diameter, shaft temperature and housing
temperature under operating condition.

27／62

NTN

Bearing Technical Calculation Tool Usage Method

2. Calculation results display

Screen No. 16 Display of calculation result(output item) (see 1-3-4 Description of output items)
Notes, units, NTN product name
The min and max of each of the following items is displayed.
After fitting: residual clearance, fitting pressure (shaft and bearing), fitting pressure (bearing and housing), fitting
stress (inner ring), fitting stress (outer ring)
Under operating condition: operating clearance, fitting pressure (shaft and bearing), fitting pressure (bearing andhousing), fitting stress (inner ring), fitting stress (outer ring)

28／62

NTN

Bearing Technical Calculation Tool Usage Method

1-3-11. Bearing vibration frequency
1. Enter calculation conditions

Screen No. 17 Calculation conditions input window(selection item) (see 1-3-2 Description of selection items)
Bearing type
(input item) (see 1-3-3 Description of input items)
Enter the calculation details into the notes if necessary.
If the NTN product name is known
Enter the NTN product name.
If the NTN product name is unknown
Click the "Search" button and search for the relevant bearing. (see 1-3-12. Bearing search window)
Always enter the rot. speed.

29／62

NTN

Bearing Technical Calculation Tool Usage Method

2. Display of calculation result

Screen No. 18 Display of calculation result(output item) (see 1-3-4 Description of output items)
Notes, bearing type, NTN product name, rot. speed, rotational speed of cage, rotational speed of cage relative to innerring, number of load cycles of inner ring per second, number of load cycles of outer ring per second, rotational speed ofrolling element

30／62

NTN

Bearing Technical Calculation Tool Usage Method

1-3-12. Bearing search window
For bearing setting screens other than calculations for "Basic rating life," if the NTN product name is unknown, clicking the"Search" button displays the following window.
1. Bearing search window 1

Screen No. 19 Bearing search window 1(input item)
Enter at least one of inner dia., outer dia. or width.
Inner dia. :Inner dimensions of bearing (min and max) (mm)(Input example) If the inner dia. of the required bearing is 25mm or more and 30mm or less
Inner dia. (mm): enter

25

to

30

.

Outer dia. :Outer dimensions of bearing (min and max) (mm)(Input example) If the outer dia. of the required bearing is 50mm or more and 60mm or lessOuter dia. (mm): enter

50

to

60

.

Width :
Width dimensions of bearing (min and max) (mm)(Input example) If the width of the required bearing is 10mm or more and 20mm or lessWidth (mm): enter

10

to

20

.

31／62

NTN

Bearing Technical Calculation Tool Usage Method

2. Bearing search window 2

Screen No. 20 Bearing search window 2(Bearing search method)(1) For "Bearing search window 2," click the NTN product name to be used with the mouse. (the clicked bearing isdisplayed as white text on a black background to distinguish it from the others)(2) Click the "OK" button.
(3) For the bearing setting screen for each calculation, enter the searched NTN product name into the NTN product namefield.
Note 1) If the count of results exceeds 14, a scroll bar is displayed on the right edge of the screen and the screen can be
moved up and down.
Click "△" with the mouse: move the screen up
Click "▽" with the mouse: move the screen down

32／62

NTN

Bearing Technical Calculation Tool Usage Method

1-4. Warning screens
1-4-1. Basic rating life(1) "The entered load is too large. Contact NTN for more information."
The equivalent load calculated from the entered load conditions is a larger value than either "Basic dynamic load
ratings ÷2" or "Basic static load ratings" for all bearings corresponding to the bearing selection conditions.
For expansion compensating brgs., this is also displayed when the equivalent load exceeds the limiting load.
(2) "The entered rotational speed exceeds the limiting speed. Contact NTN for more information."
The entered rot. speed is a value larger than the adjusted limiting speed of all bearings that correspond to the bearing
selection conditions.
(3) "The entered load is too large and the limiting speed cannot be adjusted. Contact NTN for more information."
If C/P < 5, the above warning is displayed.
(4) The axial load is too large for the radial load to adjust the limiting speed. Contact NTN for more information."
For deep groove ball brgs., expansion compensating brgs., miniature ball brgs. (metric series), angular contact ballbrgs. (30˚, 40˚), tapered roller brgs. (metric series), tapered roller brgs. (inch series), when Fa/Fr > 2.0, the above
warning is displayed. For spherical roller brgs., when either Fa/Fr > 2.0 or Fa/Fr > 2･e , the above warning isdisplayed.
(5) "dp･n < 10000. (see manual for quantity symbols) Contact NTN for more information."
If dp･n < 10000 from the entered rot. speed and bearing inner dia. and outer dia., the above warning is displayed.
(6) "Axial loads cannot be taken into account for life calculations with cylindrical roller brgs. For cylindricalroller brgs. (NJ, NUP, NF type) with an axial load placed on them, a separate limiting axial load must be
considered."
If an axial load is entered to calculate the life of cylindrical roller brgs. and double row cylindrical roller brgs., theabove warning is displayed.

1-4-2. Gear load and basic rating life, bearing load and basic rating life(1) "The load placed on bearing A is too large. Contact NTN for more information."If there is even one bearing with the equivalent load calculated from the load placed on each bearing that exceeds"basic dynamic load ratings) ÷2" or "(basic static load ratings)" of each bearing, the above warning is displayed. An
example of the above example is when the load placed on bearing A exceeds either "basic dynamic load ratings) ÷2"or "(basic static load ratings)."
For expansion compensating brgs., this is also displayed when the equivalent load exceeds the limiting load.
(2) "The input rotational speed of bearing A exceeds the limiting speed. Contact NTN for more information."If there is even one bearing with the rot. speed acting on each bearing that exceeds the adjusted limiting speed ofeach bearing, the above warning is displayed.
An example of the above example is when the rot. speed acting on bearing A exceeds the adjusted limiting speed.
(3) "The load placed on bearing A is too large and the limiting speed cannot be adjusted. Contact NTN for more
information."
If either bearing is C/P <5, the above warning is displayed. An example of the above is when the load placed on
bearing A is C/P < 5.
(4) "For bearing A, the axial load is too large for the radial load. Contact NTN for more information."
For deep groove ball brgs., expansion compensating brgs., miniature ball brgs. (metric series), angular contact ballbrgs. (30˚, 40˚), tapered roller brgs. (metric series), tapered roller brgs. (inch series), when Fa/Fr > 2.0, the above
warning is displayed. An example of the above is when the load placed on bearing A is Fa/Fr > 2.0.

33／62

NTN

Bearing Technical Calculation Tool Usage Method(5) "For bearing A, the axial load is too large for the radial load to adjust the limiting speed. Contact NTN for
more information."
For spherical roller brgs., when either Fa/Fr > 2.0 or Fa/Fr > 2･e , the above warning is displayed.
(6) "For bearing A, dp･n < 10000. (see manual for quantity symbols) Contact NTN for more information."
For either bearing, if dp･n < 10000 from the entered rot. speed and bearing inner dia. and outer dia., the above
warning is displayed.
(7) "Axial loads cannot be taken into account for life calculations with cylindrical roller brgs. For cylindricalroller brgs. (NJ, NUP, NF type) with an axial load placed on them, a separate limiting axial load must be
considered."For either bearing, if an axial load is entered to calculate the life of cylindrical roller brgs. and double row cylindricalroller brgs., the above warning is displayed.
(8) "Is it OK to place an axial load on two bearings?"
For "Bearing load and basic rating life," if an axial load is placed on two bearings other than angular contact ball brgs.
or tapered roller brgs., the above warning is displayed. If YES, proceed to the next step. If NO, return to the bearing
selection screen and reselect the axial load.

1-4-3. Operating clearance calculation(1) "The clearance is negative. Check the values again."If the min residual clearance or the min operating clearance is negative, the above warning is displayed. A calculation
result is output.
(2) "Interference is out of the standard of safety. Review the fit."¡Max fitting stress after fitting (inner ring)¡Max fitting stress under operating condition (inner ring)If either of these exceeds 127 MPa, the above warning is displayed. A calculation result is output.
(3) "The conditions to use the bearing are not suitable because of high temperature."
If a temperature that exceeds 150˚C has been entered for the shaft temperature under operating condition or the
housing temperature under operating condition, the above warning is displayed. A calculation result is output.

34／62

NTN

Bearing Technical Calculation Tool Usage Method

1-5. Error messages
1-5-1. Basic rating life(1) "Select a bearing type"In the 1-3-7-1. Bearing selection window, clicking the "OK" button without selecting a bearing type displays the above
error message.
(2) "The NTN product name is incorrect"
In the 1-3-7-1. Bearing selection window, clicking the "OK" button after entering an incorrect NTN product namedisplays the above error message.
(3) "The inner dia. (MIN > MAX) is incorrect"
In the 1-3-7-1. Bearing selection window, clicking the "OK" button with the (min) > (max) for the entered dimensions(inner dia., outer dia., width) displays the above error message.
(4) "Fa/Co > 0.5. Life calculation is not possible (see manual for quantity symbols) Contact NTN for more
information."
If an NTN product name has been entered, if the entered axial load (Fa) is not within the 0 ≤ Fa/ Co ≤ 0.5 range fordeep groove ball brgs., the above error message is displayed.
(5) "Fa/Co > 0.3. Life calculation is not possible (see manual for quantity symbols) Contact NTN for more
information."
If an NTN product name has been entered, if the entered axial load (Fa) is not within the 0 ≤ Fa/Co ≤ 0.3 range forminiature ball brgs., the above error message is displayed.
(6) "The calculation is not possible because the equivalent load (P) = 0."
If an NTN product name has been entered, when both the radial load and axial load have not been entered in the 1-37-2. Operating conditions input window, the above error message is displayed.
(7) "Equivalent load 0 division"
If an NTN product name has been entered, when the rot. speed has not been entered in the 1-3-7-2. Operating
conditions input window, the above error message is displayed.
(8) Enter a number of 10 or less for the number of steps"
If nothing has been entered, or a value of 11 or more has been entered as the number of steps in the 1-3-7-2.
Operating conditions input window and the "Calculate" button is clicked, the above error message is displayed.
(9) "No applicable data could be found"
When selecting "deep groove ball brgs." or "expansion compensating brgs." as the bearing type in the 1-3-7-1.
bearing selection window and entering the dimensions to search for bearings, if it is not within the 0 ≤ Fa/Co ≤ 0.5
range from the entered operating conditions, the above error message is displayed. Also, when selecting "miniatureball brgs." as the bearing type and entering the dimensions to search for bearings, if it is not within the 0 ≤ Fa/Co ≤0.3 range from the entered operating conditions, the above error message is displayed.
When entering dimensions and searching for bearings in the 1-3-7-1. Bearing selection window, if both the radial load
and axial load have not been entered in the 1-3-7-2. Operating conditions input window, the above error message isdisplayed.
When entering dimensions and searching for bearings in the 1-3-7-1. Bearing selection window, if the rot. speed has
not been entered in the 1-3-7-2. Operating conditions input window, the above error message is displayed.

35／62

NTN

Bearing Technical Calculation Tool Usage Method(10) "No bearings meet the required life with these operating conditions"
If there are no bearings that meet the required life when entering the operating conditions and clicking the "Calculate"button, the above error message is displayed.

1-5-2. Gear load and basic rating life, bearing load and basic rating life(1) "Select a bearing type"In the 1-3-8-1. Bearing setting and 1-3-9-1. Bearing setting window, clicking the "OK" button without selecting at least
one bearing type displays the above error message.
(2) "Enter the NTN product name"In the 1-3-8-1. Bearing setting and 1-3-9-1. Bearing setting window, clicking the "OK" button without selecting
entering the NTN product name displays the above error message.
(3) "The NTN product name is incorrect"
In the 1-3-8-1. Bearing setting and 1-3-9-1. Bearing setting window, clicking the "OK" button after entering an
incorrect NTN product name displays the above error message.
(4) "The inner dia. (MIN > MAX) is incorrect"
In the 1-3-8-1. Bearing setting and 1-3-9-1. Bearing setting window, when clicking the "Search" button and searchingfor bearings, clicking the "Search" button with the (min) > (max) for the entered dimensions (inner dia., outer dia.,width) displays the above error message.
(5) "Enter the correct value for distance bet. bearings"
In the 1-3-8-1. Bearing setting and 1-3-9-1. Bearing setting window, clicking the "OK" button without entering the
distance between bearing A and bearing B, or the distance between bearing C and bearing D (or the distance bet.
effective load for angular contact ball brgs. and tapered roller brgs.) displays the above error message.
(6) "Wrong combination of the contact ang. ort."
In the 1-3-8-1. Bearing setting and 1-3-9-1. Bearing setting window, when angular contact ball brgs., tapered roller
brgs. (metric series) or tapered roller brgs. (inch series) are selected, if the contact ang. ort. has been selected but
the same angle has been selected for both contact angles, the above error message is displayed.
(7) "Bearing type not applicable."In the 1-3-8-1. Bearing setting and 1-3-9-1. Bearing setting window, if bearing A and bearing B, or bearing C andbearing D is set as angular contact ball brgs. or tapered roller brgs., and the other is set as bearings other thanangular contact ball brgs. or tapered roller brgs., the above error message is displayed.
(8) "The total frequency is not 100%"In the 1-3-8-2. Gear specification input window, if the total frequency is not 100%, completely entering the gear
specifications and clicking the "Calculate" button displays the above error message.
(9) "Calculation error"
In the 1-3-8-2. Gear specification input window, clicking the "Calculate" button without entering any frequency at all
displays the above error message.
(10) "The calculation not possible because the equivalent load (P) = 0 [Bearing A (condition 1)]"In the 1-3-8-2. Gear specification input window, if only the input tor. of the gear specifications are not entered but
other items are entered, clicking the "Calculate" button clears all gear loads (tangent dir., radial dir., axial dir.) in<Gear loads> in the 1-3-8-3 Calculation results display window. Clicking the "Bearing life" button here displays theabove error message.

36／62

NTN

Bearing Technical Calculation Tool Usage Method(11) "The calculation not possible because the rot. speed (n) = 0 [Bearing A (condition 1)]"In the 1-3-8-2. Gear specification input window, if only the rot. speed of the gear specifications are not entered but
other items are entered, clicking the "Calculate" button clears all rot. speeds for gear A and gear B in <Gear loads> inthe 1-3-8-3 Calculation results display window. Clicking the "Bearing life" button here displays the above error
message.
(12) "Enter the correct value for gear specifications"
In the 1-3-8-2. Gear specification input window, if at least one of the number of teeth and module of gear A and gear
B have not been entered, clicking the "Calculate" button displays the above error message.
(13) "Enter the correct value for rot. speed"
In the 1-3-9-2. Load conditions input window, clicking the "OK" button without entering the rot. speed displays theabove error message.
(14) "The calculation not possible because the equivalent load (P) = 0 [Bearing A]"
In the 1-3-9-2. Load conditions input window, clicking the "OK" button without entering any loads at all displays theabove error message.
(15) "Fa/Co > 0.5 for bearing A. Life calculation is not possible (see manual for quantity symbols) Contact NTN
for more information."
If any of the bearings include deep groove ball brgs., and the axial load placed on those bearings is not within the 0 ≤Fa/Co ≤ 0.5 range, the above error message is displayed.
(16) "Fa/Co> 0.3 for bearing A. Life calculation is not possible (see manual for quantity symbols) Contact NTN for
more information."
If any of the bearings include miniature ball brgs., and the axial load placed on those bearings is not within the 0 ≤Fa/Co ≤ 0.3 range, the above error message is displayed.

1-5-3. Operating clearance calculation(1) "Required items have not been entered"
In the 1-3-10-1. Operating conditions input window, clicking the "Calculate" button with no selection items selected atall, or not entering the NTN product name, the above error message is displayed.
(2) "Select a bearing type"In the 1-3-10-1. Operating conditions input window, clicking the "Search" button of the NTN product name without
selecting a bearing type displays the above error message.
(3) "The NTN product name is incorrect"
In the 1-3-10-1. Operating conditions input window, clicking the "Calculate" button with an incorrect NTN productname entered, or if the bearing type and the NTN product name do not match, the above error message is displayed.
(4) "Bearing inner diameter ≤ Shaft bore diameter. Impossible to calculate."
In the 1-3-10-1. Operating conditions input window, clicking the "Calculate" button with the entered shaft bore
diameter exceeding the bearing inner dia. displays the above error message.
(5) "The value of inner dia. (housing outer diameter) is inappropriate"
In the 1-3-10-1. Operating conditions input window, clicking the "Calculate" button with the entered shaft bore
diameter (housing outer diameter) value negative or a character other than a number displays the above error
message.

37／62

NTN

Bearing Technical Calculation Tool Usage Method(6) "Housing outer diameter ≤ Bearing outer diameter. Impossible to calculate."
In the 1-3-10-1. Operating conditions input window, clicking the "Calculate" button with the entered housing outer
diameter less than the bearing outer dia. value displays the above error message.
(7) "The value of the shaft (housing) temperature under operating condition is inappropriate."
In the 1-3-10-1. Operating conditions input window, clicking the "Calculate" button with the entered shaft (housing)temperature under operating conditions other than a number displays the above error message.
(8) "MIN inner dia. is incorrect"
In the 1-3-10-1 Operating conditions input window, when clicking the NTN product name "Search" button andsearching for bearings, clicking the "Search" button with the entered dimensions (inner dia., outer dia., width) otherthan a number, the above error message is displayed.
(9) "The inner dia. (MIN > MAX) is incorrect"
In the 1-3-10-1 Operating conditions input window, when clicking the NTN product name "Search" button andsearching for bearings, and(1) The "Search" button is clicked with (min) entered for dimensions (inner dia., outer dia., width) > (max),(2) The "Search" button is clicked without entering a min value for dimensions (inner dia., outer dia., width) and anegative value entered of max, the above error message is displayed.
(10) "No applicable data could be found"
In the 1-3-10-1 Operating conditions input window, clicking the NTN product name "Search" button and searching forbearings, and there are bearings that meet the conditions for dimensions (inner dia., outer dia., width), the above
error message is displayed.
(11) "Precision symbols are not defined for large diameter bearings"
In the 1-3-10-1. Operating conditions input window, clicking the "Calculate" button with both an NTN product namewith a large inner dia. and outer dia., and precision symbols that have not been defined with JIS have been entered
for those inner dia. and outer dia., the above error message is displayed.
(12) "Fit symbols are not defined for large diameter bearings"
In the 1-3-10-1. Operating conditions input window, clicking the "Calculate" button with both an NTN product namewith a large inner dia. and outer dia., and fitting symbols that have not been defined with JIS have been entered for
those inner dia. and outer dia., the above error message is displayed.

1-5-4. Bearing vibration frequency(1) "Required items have not been entered"
In the 1-3-11-1. Calculation conditions input window, clicking the "Calculate" button without either the bearing type,
NTN product name or rot. speed entered, the above error message is displayed.
(2) "The corresponding bearing type does not exist"
In the 1-3-11-1. Calculation conditions input window, clicking the "Search" button of the NTN product name without
selecting a bearing type displays the above error message.
(3) "The NTN product name is incorrect"
In the 1-3-11-1. Calculation conditions input window, clicking the "Calculate" button with an incorrect NTN productname entered, or if the bearing type and the NTN product name do not match, the above error message is displayed.

38／62

NTN

Bearing Technical Calculation Tool Usage Method(4) "The value of rot. speed is inappropriate"
In the 1-3-11-1. Calculation conditions input window, clicking the "Calculate" button with the entered rot. speed value
negative or a character other than a number displays the above error message.
(5) "MIN inner dia. is incorrect"
In the 1-3-11-1 Calculation conditions input window, when clicking the NTN product name "Search" button andsearching for bearings, clicking the "Search" button with the entered dimensions (inner dia., outer dia., width) otherthan a number, the above error message is displayed.
(6) "The inner dia. (MIN > MAX) is incorrect"
In the 1-3-11-1 Calculation conditions input window, when clicking the NTN product name "Search" button andsearching for bearings, and(1) The "Search" button is clicked with (min) entered for dimensions (inner dia., outer dia., width) > (max),(2) The "Search" button is clicked without entering a min value for dimensions (inner dia., outer dia., width) and anegative value entered of max, the above error message is displayed.
(7) "No applicable data could be found"
In the 1-3-11-1 Calculation conditions input window, clicking the NTN product name "Search" button and searchingfor bearings, and there are bearings that meet the conditions for dimensions (inner dia., outer dia., width), the above
error message is displayed.

39／62

NTN

Bearing Technical Calculation Tool Usage Method

1-6. Calculation formula
1-6-1. Description of quantity symbols
Kt …………………：Tangent dir. load of gear(N)

Ks …………………：Radial dir. load of gear(N)

Ka …………………：Axial dir. load of gear(N)

M……………………：Torque applied to gear

(N･mm)

z ……………………：Teeth of gear
m …………………：Module of gearz・m
Dp ：Pitch diameter of gear（＝—————）
cosβ

(mm)

α …………………：Pres. angle of gear
β …………………：Twisting angle of gear (helical gear only)
SB1 …………………：Distance between bearing A and bearing B(mm)

SG1 …………………：Distance between bearing A and gear A(mm)

SB2 …………………：Distance between bearing C and bearing D(mm)

SG2 …………………：Distance between bearing C and gear B(mm)

DpA …………………：Pitch diameter of gear A(mm)

DpB …………………：Pitch diameter of gear B(mm)

Fr …………………：Radial load placed on bearing(N)

Fa …………………：Axial load placed on bearing(N)

FrA …………………：Radial load placed on bearing A(N)

FrB …………………：Radial load placed on bearing B(N)

FrC …………………：Radial load placed on bearing C(N)

FrD …………………：Radial load placed on bearing D(N)

FaA …………………：Axial load placed on bearing A(N)

FaB …………………：Axial load placed on bearing B(N)

P ……………………：Equivalent load(N)

Pr …………………：Equivalent radial load(N)

Pa …………………：Equivalent axial load(N)

Pm …………………：Average value of equivalent load

(N)

Pi……………………：Equivalent load placed on each step(N)

Pmin …………………：Min value of equivalent load(N)

Pmax ………………：Max value of equivalent load(N)

p ……………………：Life calculation formula index
Ball bearings P = 3
Roller bearings P = 10/3
n ……………………：Rot. speed(min-1)

ni …………………：Rot. speed of each step(min-1)

nm …………………：Average value of rot. speed(min-1)n1,n2,…nn …………：Rot. speed of each step(min-1)

ti ……………………：Use rate of each step(hours or %)t1,t2,…tn ……………：Use rate of each step(hours or %)X ……………………：Radial load coefficient
Y ……………………：Axial load coefficient
YA …………………：Axial load coefficient of bearing A
YB …………………：Axial load coefficient of bearing B

40／62

NTN

Bearing Technical Calculation Tool Usage Method

Fri …………………：Radial load placed on shaft load center(N)

Fmi …………………：Moment load placed on shaft load center(N･mm)

L1 …………………：Distance from bearing A to load center(mm)

LB …………………：Distance from bearing A to bearing B(mm)

L10h …………………：Basic rating life

(hours)

LT …………………：Total life of bearing system(hours)

Lt …………………：Total life of bearing unit

(hours)

LA …………………：Basic rating life of bearing A(hours)

LB …………………：Basic rating life of bearing B(hours)

L10hi ………………：Basic rating life under each meshing condition(hours)

C ……………………：Basic dynamic load ratings(N)e ……………………：When both are ball bearings e=10/9
When both are tapered roller bearings e=9/8
When one is a ball bearing, and the other is a tapered roller bearing e=(10/9+9/8)/2
qi ……………………：Frequency of gear meshing conditions(%)

S ……………………：Shaft bore diameter(mm)

H……………………：Housing outer diameter(mm)

TS …………………：Shaft temperature under operating condition(˚C)

TH …………………：Housing temperature under operating condition(˚C)

d ……………………：Bearing inner dia.: (nominal dimensions)(mm)

D ……………………：Bearing outer dia.: (nominal dimensions)(mm)ddmin ………………：Min value of bearing inner dia. tolerance(mm)

ddmax ………………：Max value of bearing inner dia. tolerance(mm)

DDmin ………………：Min value of bearing outer dia. tolerance(mm)

DDmax ………………：Max value of bearing outer dia. tolerance(mm)

SSmin ………………：Min value of shaft outer dia. tolerance(mm)

SSmax ………………：Max value of shaft outer dia. tolerance(mm)

HHmin ………………：Min value of housing outer dia. tolerance(mm)

HHmax ………………：Max value of housing outer dia. tolerance(mm)

Cr min ………………：Min value of radial internal clearance(mm)

Cr max ………………：Max value of radial internal clearance(mm)

ES …………………：Young's modulus of shaft(MPa)νS …………………：Poisson's ratio of shaft
αS …………………：Coefficient of linear thermal expansion of shaft(1/˚C)

EH …………………：Young's modulus of housing(MPa)

νH …………………：Poisson's ratio of housing
αH …………………：Coefficient of linear thermal expansion of housing(1/˚C)

EB …………………：Young's modulus of bearing inner ring, outer ring

( = 208000 MPa)dm …………………：Average inner ring groove diameter(mm)

Dm …………………：Average outer ring groove diameter(mm)

Dr …………………：Outer ring groove diameter(mm)

So …………………：Expansion of shaft outer dia. nominal dimensions taking into account temperature(mm)

do …………………：Expansion of bearing inner dia. nominal dimensions taking into account temperature(mm)

Do …………………：Expansion of bearing outer dia. nominal dimensions taking into account temperature(mm)

Ho …………………：Expansion of housing inner dia. nominal dimensions taking into account temperature(mm)

mi …………………：Average value of interference of shaft and inner ring(mm)

σi …………………：Standard deviation of interference of shaft and inner ring(mm)mo …………………：Average value of interference of outer ring and housing(mm)

σo …………………：Standard deviation of interference of outer ring and housing

(mm)

41／62

NTN

Bearing Technical Calculation Tool Usage Method

λi …………………：Average inner ring groove diameter coefficient of expansion
λo …………………：Average outer ring groove diameter coefficient of expansion
Mi …………………：Average value of clearance reduction due to fitting with inner ring and shaft(mm)

Σi …………………：Standard deviation of clearance reduction due to fitting with inner ring and shaft (mm)Mo …………………：Average value of clearance reduction due to fitting with outer ring and housing(mm)Σo …………………：Standard deviation of clearance reduction due to fitting with outer ring and housing(mm)

Δt …………………：Clearance reduction due to temperature difference of shaft and housing(mm)

Um …………………：Average value of operating clearance(mm)Uσ …………………：Standard deviation of operating clearance(mm)

QS，Qi，QO，QH，mf，σf，tO，μt，σt ……………………………：values used during calculations
Umin…………………：Min value of operating clearance(mm)

Umax ………………：Max value of operating clearance(mm)

Pi min ………………：Min value of fitting pressure (shaft and bearing)(MPa)

Pi max ………………：Max value of fitting pressure (shaft and bearing)(MPa)

σi min ………………：Min value of fitting stress (inner ring)(MPa)

σi max ………………：Max value of fitting stress (inner ring)(MPa)

Po min ………………：Min value of fitting pressure (bearing and housing)(MPa)

Po max ………………：Max value of fitting pressure (bearing and housing)(MPa)

σo min ………………：Min value of fitting stress (outer ring)(MPa)

σo max ………………：Max value of fitting stress (outer ring)(MPa)ni …………………：Rot. speed of inner ring(min-1)

α0 …………………：Contact ang.

(˚)

Z ……………………：Number of rolling elements(No.)

Dw …………………：Rolling element diameter(mm)dpw …………………：Rolling element pitch diameter(mm)nc …………………：Rotational speed of cage(Hz)

nci …………………：Rotational speed of cage relative to inner ring(Hz)

fc ……………………：Number of load cycles of inner ring per second(Hz)

fce …………………：Number of load cycles of outer ring per second(Hz)na …………………：Rotational speed of rolling element(Hz)

L10mh ………………：Modified rating life

(hours)aISO ………………：Modified rating life factor
ec …………………：Contamination factor
Cu …………………：Fatigue limit load(N)v ……………………：Viscosity during operation
v1 …………………：Reference kinematic viscosityκ …………………：Viscosity ratio(mm2/s)(mm2/s)

42／62

NTN

Bearing Technical Calculation Tool Usage Method

1-6-2. Gear load
2･M
Kt＝———
Dp
Ks＝Kt･tanα (spur)tanα＝Kt･————— (helical gear)cosβ
Ka＝Kt･tanβ (helical gear only)
Each positive and negative gear load in this catalog has been set from the rotation direction of the input shaft whenviewing bearing A from bearing B, and the twisting direction of each gear as in Table 1.
Table 1 Positive and negative of each gear load
Rotation directionof input shaft

Twisting directionof gear

Tangent dir.
load

Radial dir.
load

Axial dir.
load

Right screw
Left screw
Right screw
Gear B
Left screw
Right screw
Gear A
Left screw
Right screw
Gear B
Left screw

Pos.
Pos.
Neg.
Neg.
Neg.
Neg.
Pos.
Pos.

Neg.
Neg.
Pos.
Pos.
Neg.
Neg.
Pos.
Pos.

Neg.
Pos.
Neg.
Pos.
Pos.
Neg.
Pos.
Neg.

Gear A
Clockwise

Counterclockwise

Note 1) Axial dir. load not taken into account for spurs.
Note 2) Gear twisting direction not taken into account for spurs.

1-6-3. Load distribution on bearings
1. Gear load
Radial load (applies to both spurs and helical gears)
1) When the twisting direction of gear A is right and the directionof rotation is clockwise, or the twisting direction of gear A isleft and the direction of rotation is counterclockwise,

SB1
SG1

Gear A

2

B

FrA=

SB1− SG1
SB1− SG1
DpA
Ks ＋
Ka
Kt ＋
SB1
SB1
2･SB1

FrB=

SG1
SG1
DpA
Ks −
Ka
Kt ＋
SB1
SB1
2･SB1

FrC=

SB2− SG2
SB2− SG2
DpB
Ks −
Ka
Kt ＋
SB2
SB2
2･SB2

FrD=

SG2
SG2
DpB
Ks ＋
Ka
Kt ＋
SB2
SB2
2･SB2

DpA

A

2

2

2

D
DpB

C

2

Gear A
SG2
SB2

43／62

2

2

2

NTN

Bearing Technical Calculation Tool Usage Method

2) When the twisting direction of gear A is left and the direction of rotation is clockwise, or the twisting direction of gear A isright and the direction of rotation is counterclockwise,2

FrA=

SB1− SG1
SB1− SG1
DpA
Ks −
Ka
Kt ＋
SB1
SB1
2･SB1

FrB=

SG1
SG1
DpA
Ks ＋
Ka
Kt ＋
SB1
SB1
2･SB1

FrC=

SB2− SG2
SB2− SG2
DpB
Ks ＋
Ka
Kt ＋
SB2
SB2
2･SB2

FrD=

SG2
SG2
DpB
Ks −
Ka
Kt ＋
SB2
SB2
2･SB2

2

2

2

2

2

2

2

Note 1) For spurs, Ka= 0

Axial load (helical gear only)
1) Angular contact ball brgs. and tapered roller brgs.
If a radial load (Fr) is placed on angular contact ball brgs. and tapered roller brgs., a component force is generated in theaxial direction. This is called the induced thrust load (Fa'). The size of the induced thrust load is determined with thefollowing formula.
0.5･FrFa'＝——————………………(N or kgf)
Y
The calculation of the axial load and equivalent load of each bearing when angular contact ball brgs. and tapered roller
brgs. are positioned opposite each other.
(a) Back-to-back arrangement
BearingABack(a) Face-to-face arrangement
BearingA

BearingB

Front

Bearing
B

Ka

Ka
FrB
FrA

FrB

0.5･FrB
0.5･FrA(1) For —————≦—————＋Ka
YA
YB
FaA=

0.5･FrA
0.5･FrB(1) For —————≦—————＋Ka
YB
YA

0.5･FrB
＋ Ka
YB

FaA=

FaB= 0.5･FrA ＋Ka
YAFaB= 0.5･FrB
YB
0.5･FrA
0.5･FrB(2) For —————＞—————＋Ka
YA
YB
FaA=

0.5･FrA
YA

0.5･FrB
0.5･FrA(2) For —————＞—————＋Ka
YB
YA

0.5･FrAYA

FaA=

FaB= 0.5･FrA −Ka
YA

0.5･FrB− Ka
YB

FaB= 0.5･FrB
YB

44／62

FrA

NTN

Bearing Technical Calculation Tool Usage Method

1) Other bearings
If there is an instruction to place an axial load on the bearing setting screen, place an axial load on the bearing.
(1) If the load is placed on a single row, the entire axial load is placed on those bearings.
(2) If the load is placed on two rows, half the axial load is placed on those bearings.

2. Load placed on shafts
Radial load
Bearing radial load calculated from the radial load and moment load placed on the shaft load center

FrA=
FrB=

LB − L1
Fm1
Fr1 −
LB
LB
L1
Fm1
Fr1＋
LB
LB

L1

Fr1

Bearing A

Bearing B

Fm1
LB
FrA

FrB

Axial load
1) Angular contact ball brgs. and tapered roller brgs.
Replacing the axial dir. load (Ka) of the gear with the axial load (Fa) placed on the shaft means the calculation method is
the same as 1-6-3-1.2 Axial load of the gear load.
2) Other bearings
If there is an instruction to place an axial load on other bearing setting screens, place an axial load on the bearing.
(1) If the load is placed on a single row, the entire axial load is placed on those bearings.
(2) If the load is placed on two rows, half the axial load is placed on those bearings.

45／62

NTN

Bearing Technical Calculation Tool Usage Method

1-6-4. Calculation of equivalent load
1. Radial bearings excluding cylindrical roller brgs.
1) Application bearings ：Deep Groove Ball Brgs.
Expansion Compensating Brgs.
Miniature Ball Brgs.
Angular Contact Ball Brgs.
Double Row Angular Contact Ball Brgs.
Self-Aligning Ball Brgs.
Tapered Roller Brgs. (Metric series)
Tapered Roller Brgs. (Inch series)
Double Row Tapered Roller Brgs. (Outward facing type)Double Row Tapered Roller Brgs. (Inward facing type)
Spherical Roller Brgs.
2) Equivalent load formula
Pr＝X･Fr＋Y･Fa
2. Cylindrical Roller Brgs.
1) Application bearings ：Cylindrical Roller Brgs
Double Row Cylindrical Roller Brgs.
2) Equivalent load formula
Pr＝Fr
3. Thrust Spherical Roller Brgs.
1) Application bearings ：Thrust Spherical Roller Brgs.
2) Equivalent load formula
Pa＝Fa＋1.2･Fr (however, Fr/Fa ≤ 0.55)
4. Thrust Spherical Roller Brgs.
1) Application bearings ：Four-Point Contact Ball Brgs.
Thrust Ball Brgs.
Double Row Thrust Ball Brgs.
Thrust Cylindrical Roller Brgs.
2) Equivalent load formula
Pa＝Fa

1-6-5. Calculation of average equivalent load when calculating bearing unit life
p

Pm=

1

Σ（ Pi･ni･ti ） p
Σ（ ni･ti ）

46／62

NTN

Bearing Technical Calculation Tool Usage Method

1-6-6. Calculation of basic rating life

L10h=

106
60･n

C
P

p

Note 1) For bearing unit life calculations, if there are 2 or more steps, enter the average value of the rot. speed determinedwith the following formula into the rot. speed of the above formulan1・t1＋n2・t2…nn・tn
t1＋t2…tn

nm=

1-6-7. Calculation of total life of bearing system
Determine the total life of the shaft supported by bearing A and bearing B as follows.
LT=

1
e 1e
（1/LA）＋（1/LB）

｛

e

｝

1-6-8. Total life of the bearing unit calculated from the frequency of meshing conditions of the gearin 1-3-8. Gear load and basic rating life
Lt=

100
qi
Σ L10hi

1-6-9. Calculation of average inner ring groove diameter, average outer ring groove diameter
The average inner ring groove diameter dm, average outer ring groove diameter Dm and outer ring groove diameter Dr is
calculated with the following formula.

Table 1 Average inner and outer ring groove diameter, outer ring groove diameter
Bearing type

dm

Dm

Dr

Deep Groove Ball Brgs.

4d＋D
1.05・—————
5d＋4D
0.95・—————
5

d＋4D
—————
5

Cylindrical Roller Brgs.

3d＋D
1.05・—————
4

d＋3D
0.98・—————
4

d＋3D
—————
4

Spherical Roller Brgs.

2d＋D
—————
3

d＋4D
0.97・—————
5

d＋4D
—————
5

1-6-10. Expansion of each component dimension taking into account shaft and housing temperature
Calculate expansion of each component dimension taking into account shaft and housing temperature with the following
formula.
（TS−20）S0＝d・αS・（TS−20）d0＝d・12.5・10−6・（TH−20）
D0＝D・12.5・10−6・（TH−20）
H0＝D・αH・

47／62

NTN

Bearing Technical Calculation Tool Usage Method

1-6-11. Calculation of inner ring and shaft
1-6-11-1. Calculation of average value of interference of inner ring and shaft, and standard deviation ofinterference of inner ring and shaft
Calculate the average value of interference mi and standard deviation of interference σi of the inner ring and shaft
with the following.
① Calculate（S0＋SS1）−（d0＋dd2）
If （S0＋SS1）−（d0＋dd2）≧0, proceed to ②,
If （S0＋SS1）−（d0＋dd2）＜0, proceed to ③.
② Interference calculation for interference fit
mi=

σi=

d
2･S0＋ SS1＋ SS2 2･d0＋ dd1＋ dd2
−
･
d ＋3
2
2
SS2 − SS1
2･3

2

＋

dd2 − dd1
2･3

2

･

d
d ＋3
(end of 1-6-11-1)③ Calculate（S0＋SS2）−（d0＋dd1）
If （S0＋SS2）−（d0＋dd1）＞0, proceed to ④,
If （S0＋SS2）−（d0＋dd1）≦0, proceed to ⑤.
④ Interference calculation for transition fit
mf=

σf=

d
2･S0＋ SS1＋ SS2 2･d0＋ dd1＋ dd2
−
･
d ＋3
2
2
SS2 − SS1
2･3

2

＋

dd2 − dd1
2･3

2

･

d
d ＋3

If t0 = -mf/σf, determine μt, σt from Table 2.
Table 2 μt・σt calculation chart
t0

μt

σt

t0

μt

σt

−3.0
−2.8
−2.6
−2.4
−2.2
−2.0
−1.8
−1.6
−1.4
−1.2
−1.0
−0.9
−0.8
−0.6
−0.5
−0.4
−0.3
−0.2
−0.1
−0

0.00040.00080.00150.0027
0.005
0.008
0.014
0.023
0.037
0.056
0.083
0.100
0.120
0.143
0.169
0.198
0.230
0.267
0.307
0.351
0.399

0.999
0.998
0.996
0.993
0.988
0.980
0.969
0.953
0.931
0.902
0.867
0.846
0.823
0.799
0.772
0.744
0.714
0.683
0.651
0.618
0.577

0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0

0.451
0.509
0.567
0.630
0.698
0.769
0.843
0.920
1.000
1.083
1.256
1.437
1.623
1.814
2.008
2.205
2.40272.60152.80083.0004

0.549
0.515
0.480
0.446
0.412
0.380
0.349
0.318
0.289
0.262
0.211
0.168
0.131
0.100
0.075
0.056
0.041
0.029
0.020
0.014

※Areas between each value are calculated with linear interpolation. If t0 < -3.0 and 3.0 < t0,
conduct the calculation using the -3.0 ≤ t0 ≤-2.8 and 2.8≤ t0 ≤3.0 interpolation curve.

Using μt and σt from Table 2,
mi＝mf＋μt・σt
σi＝σt・σf(end of 1-6-11-1)⑤ Interference calculation for clearance fit
mi＝0，σi＝0(end of 1-6-11-1)

48／62

NTN

Bearing Technical Calculation Tool Usage Method

1-6-11-2. Calculation of average inner ring groove diameter coefficient of expansion
Calculate the average inner ring groove diameter coefficient of expansion λi with the following.
Qi=

dm2 ＋ d 2
dm2 − d 2Qs=λi=

d 2 ＋S2d 2 −S2
Es･（Qi＋1）d･＋EB･（Qs−vs） dm
Es･（Qi＋0.3）

1-6-11-3. Calculation of clearance reduction due to fitting with inner ring and shaft
Calculate the average value Mi and standard deviation Σi of clearance reduction due to fitting of the inner ring andshaft.
Σi =σi ･λiMi =mi ･λi

1-6-12. Outer ring and housing calculation
1-6-12-1. Calculation of average value of interference of outer ring and housing, and standard deviation ofinterference of outer ring and housing
Calculate the average value of interference m0 and standard deviation of interference σ0 of the outer ring andhousing with the following.
① Calculate（D0＋DD1）−（H0＋HH2）
If （D0＋DD1）−（H0＋HH2）≧0, proceed to ②,
If （D0＋DD1）−（H0＋HH2）＜0, proceed to ③.
② Interference calculation for interference fit
m0=

σ0=

D
2･D0＋DD1＋ DD2
2･H0＋HH1＋HH2
−
･ D
2
2
＋3
D
DD2− DD1 2
HH2−HH1 2
＋
･ D 3
2･3
2･3
＋
(end of 1-6-12-1)③ Calculate（D0＋DD2）−（H0＋HH1）
If （D0＋DD2）−（H0＋HH1）＞0, proceed to ④,
If （D0＋DD2）−（H0＋HH1）≦0, proceed to ⑤.
④ Interference calculation for transition fit
mf=

σ f=

D
2･D0＋DD1＋ DD2
2･H0＋HH1＋HH2
−
･ D
2
2
＋3
D
DD2− DD1 2
HH2−HH1 2
＋
･ D 3
2･3
2･3
＋

If t0 = -mf/σf, determineμt,σt from Table 2.
Using μt and σt from Table 2,
m0＝mf＋μt・σt
σ0＝σt・σf(end of 1-6-12-1)⑤ Interference calculation for clearance fit
m0＝0，σ0＝0(end of 1-6-12-1)

49／62

NTN

Bearing Technical Calculation Tool Usage Method

1-6-12-2. Calculation of average outer ring groove diameter coefficient of contraction
Calculate the average outer ring groove diameter coefficient of contraction λo with the following.
Q0=

D 2＋Dm2
D 2−Dm2H 2 ＋ D2QH=
λ0=

H 2 − D2
EH･（Q0＋1）

Dm･＋EH･（Q0−0.3） D
EB･（QH＋νH）

1-6-12-3. Calculation of clearance reduction due to fitting with outer ring and housing
Calculate the average value M0 and standard deviation Σ0 of clearance reduction due to fitting of the outer ring andhousing.
M0=m0･λ0
Σ0=σ0･λ0

1-6-13. Calculation of clearance reduction due to temperature difference of shaft and housing
Calculate the clearance reduction Δt due to temperature difference of shaft and housing with the following formula
Δt＝Dr・12.5・10−6・（TS−TH）(Δt can be a negative value)

1-6-14. Operating clearance calculation
Calculate the average value Um and standard deviation Uσ of the operating clearance with the following formula.
Um=

Cr max ＋ Cr min−（Mi ＋M0＋Δt ）2Uσ=

Cr max − Cr min
2･3

2

2

2

＋Σi ＋Σ0

The min value of operating clearance Umin and max value of operating clearance Umax are the following.
Umin＝Um−3・Uσ
Umax＝Um＋3・Uσ

1-6-15. Calculation of fitting pressure (shaft and bearing), fitting stress (shaft and bearing)Calculate the fitting pressure (shaft and bearing) min value Pi min, max value Pi max, fitting stress (inner ring) min value
σi min, max value σi max with the following formulas.
−｛（S0＋SS1）（d0＋dd2）･｝dPi min=

d
＋3

2･d/2
2
2
（ S/2 ）
（dm/2）
1 −νs
1−0.3
＋ 2･
＋
−
2
2
2
2
Es
EB
Es｛
･（d/2 ）−（S/2 ）｝ EB｛･（dm/2）−（ d/2 ）｝−｛（S0＋SS2）（d0＋dd1）･｝d
Pi max=

d
＋3

2･d/2
2
2
（ S/2 ）
（dm/2）
1 −νs
1−0.3
＋ 2･
＋
−
2
2
2
2
Es
EB
Es｛
･（d/2 ）−（S/2 ）｝ EB｛･（dm/2）−（ d/2 ）｝

50／62

−
｛（S0＋SS2）（d0＋dd1）･
｝d

d
＋3

2･d/2

Pi max=2
2（ S/2 ）
（dm/2）1 −νs
1−0.3
Bearing
Technical
Calculation Tool Usage Method
＋ 2･
＋
−
2
2
2
2
Es
EB
Es ｛
･（d/2 ）−（S/2 ）｝ EB｛･（dm/2）−（ d/2 ）｝NTNσi min=σi max=2
1 ＋（ d/dm ）21−（ d/dm ）2
1 ＋（ d/dm ）21−（ d/dm ）･ Pi min･ Pi max

1-6-16. Calculation of fitting pressure (bearing and housing), fitting stress (outer ring)Calculate the fitting pressure (bearing and housing) min value P0 min, max value P0 max, fitting stress (outer ring) min
value σ0 min, max value σ0 max with the following formulas.
D−｛（D0＋DD1）（H0＋HH2）･
｝D 3
＋
2･D/2

P0 min=2
2（Dm/2）（H/2 ）
1−0.3
1 −νH
＋ 2･
＋
−
2
2
2
2
EB
EH
EB｛
･（D/2）−･（ H/2 ）−（D/2 ）｝（Dm/2）｝ EH｛

D−｛（D0＋DD2）（H0＋HH1）･
｝D 3
＋
2･D/2

P0 max=σ0 max=σ0 min=（Dm/2）（H/2 ）
1−0.3
1 −νH
＋ 2･
2
2 ＋
2
2
EB − EHEB｛（Dm/2）｝ EH｛･（D/2）−･（ H/2 ）−（D/2 ）｝2

2
1 ＋（ d/dm ）21−（ d/dm ）2
1 ＋（ d/dm ）21−（ d/dm ）2･ P0 max･ P0 min1-6-17. Calculation of bearing vibration frequency
Calculate nc, nci, fci, fce and na with the following formula.
nc=ni（･ dpw −Dw･cosα0）2･dpw･60

nci=･ dpw ＋Dw･cosα0）
ni（
2･dpw･60

fci= nci･Z
fce= nc･Z

na=･ dpw2 − Dw2 ･cos 2α0）ni（
2･dpw･Dw･60

51／62

NTN

Bearing Technical Calculation Tool Usage Method

1-6-18. Calculation of modified rating life
Modified rating life can be obtained with the following formula using the reliability factor, life modification factor, andbasic rating life.
Lnm = a1・aISO・Ln

1-6-18-1 Calculation of reliability factor a1
The value of reliability factor a1 is provided in Appendix table 18 for reliability of 90% or greater.
* The Bearing Technical Calculation Tool uses a reliability of 90% L10 , that is a1 = 1.

1-6-18-2 Calculation of modification factor aISO
Life modification factor aISO is a value obtained by integrating material characteristics and lubrication conditions, andgiven as a function like the following formula in ISO 281:2007. Specifically, it is obtained with the drawing or formula foreach bearing type indicated in 1-16-18-7.

ec Cu
aISO = f (ーーpーー k )*The Bearing Technical Calculation Tool does not support the use of a lubricant with extreme pressure additive.
Please consult NTN Engineering when using a lubricant with extreme pressure additive.

1-6-18-3 Calculation of viscosity ratioκ

Viscosity ratio for the lubricating material κ is represented by the following formula by the ratio of kinematic viscosity v
in use with respect to reference kinematic viscosity v1 of the lubricant.

vーκ= ーvー
1

Reference kinematic viscosity v1 depends on bearing rotation speed n and size (Dpw), and can be obtained with thefollowing formula or from Figure A.1.
For n < 1000 min-1, v1 ＝ 45 000 n-0.83 Dpw-0.5
For n ≥ 1000 min-1, v1 ＝ 45 000 n-0.5 Dpw-0.5

Figure A. 1

Reference kinematic viscosity v1

52／62

NTN

Bearing Technical Calculation Tool Usage Method

1-6-18-4 Calculation of reliability factor ec
As shown in Appendix table 16, approximate values are determined by the bearing size (may be substituted by rolling
element pitch diameter Dpw, average bearing diameter (d+ D ) /2), filtration and seal structures (including presence of
pre-washing).

1-6-18-5 Calculation of fatigue limit load Cu
The fatigue limit load Cu is the load applied on bearings that becomes the fatigue limit stress at the maximum loadcontact part of the raceway. This depends on the bearing type, internal specifications, quality, and material strength,
and in ISO 281:2007, 1.5 GPa is recommended as the contact stress corresponding to Cu for the bearings made ofhigh purity bearing steel. The fatigue limit load values with respect to the NTN bearing numbers are specified in eachspecification table.

1-6-18-6 Calculation of equivalent load P
1-6-4. See calculation of equivalent load.

1-6-18-7 Calculation of life modification factor aISO for each bearing typeThe value of life modification factor aISO is determined based on Figure A.2 to Figure A.5 or the following formula(A.5) to formula (A.16) calculation for each bearing type.
However, care should be taken concerning the following points.
① If aISO > 50, aISO = 50.
② Ifκ> 4, aISO is calculated withκ= 4.
③ Ifκ< 0.1, aISO cannot be calculated (the formula and figure do not apply)④ Ifκ< 1 and ec ≥ 0.2, and a lubricant containing extreme pressure additive is used, the valueκ＝1 can be used to
calculate contamination factor ec and life modification factor aISO . However, when the value for life modification
factor aISO exceeds 3 as a result of this calculation, aISO = 3.

53／62

NTN

Bearing Technical Calculation Tool Usage Method

The curved lines shown in Figure A.2 are based on formula(A.5) to formula (A.7).
If 0.1 ≤κ< 0.4,［（

aISO =0.1 1− 2.5671−

1.9987

κ0.19087）（ ） ］……（A.6）

If 1 ≤κ≤ 4,

aISO =0.1 1− 2.5671−）（ ） ］……（A.7）1/3-9.3

e c Cu

1/3

-9.3

P

0.83

1.9987e c CuP

0.83

aISO =0.1 1− 2.5671−［（……（A.5）

κ0.054381

If 0.4 ≤κ< 1,［（）（ ） ］
0.83

2.2649

κ0.071739

e c Cu

1/3

-9.3

P

Figure A.2 Life modification factor aISO (radial ball bearing)

The curved lines shown in Figure A.3 are based on formula(A.8) to formula (A.10).
If 0.1 ≤κ< 0.4,［（

aISO =0.1 1− 1.5859−

1.3993

If 0.4 ≤κ< 1,［（

aISO =0.1 1− 1.5859−

1.2348

κ0.19087

If 1 ≤κ≤ 4,［（

aISO =0.1 1− 1.5859−

Figure A.3 Life modification factor aISO (radial roller bearing)

54／62）（ ） ］……（A.8））（ ） ］……（A.9））（ ） ］……（A.10）

κ0.054381

1.2348ec Cu

0.4-9.185

P

ec Cu

0.4

-9.185P

κ0.071739

ec Cu
P

0.4

-9.185NTN

Bearing Technical Calculation Tool Usage Method

The curved lines shown in Figure A.4 are based on formula(A.11) to formula (A.13).
If 0.1 ≤κ< 0.4,［（

aISO =0.1 1− 2.5671−

1.9987

κ0.19087）（ ） ］…（A.12）

If 1 ≤κ≤ 4,

aISO =0.1 1− 2.5671−）（ ） ］…（A.13）

1/3-9.3

e c Cu

1/3

-9.3

3P

0.83

1.9987e c Cu3P

0.83

aISO =0.1 1− 2.5671−［（…（A.11）

κ0.054381

If 0.4 ≤κ< 1,［（）（ ） ］
0.83

2.2649

κ0.071739

e c Cu

1/3

-9.3

3P

Figure A.4 Life modification factor aISO (thrust ball bearing)

The curved lines shown in Figure A.5 are based on formula(A.14) to formula (A.16).
If 0.1 ≤κ< 0.4,［（

aISO =0.1 1− 1.5859−

1.3993

If 0.4 ≤κ< 1,［（

aISO =0.1 1− 1.5859−

1.2348

κ0.19087

If 1 ≤κ≤ 4,［（

aISO =0.1 1− 1.5859−

Figure A.5 Life modification factor aISO (thrust roller bearing)

55／62）（ ） ］…（A.14））（ ） ］…（A.15））（ ） ］…（A.16）

κ0.054381

1.2348ec C u0.4-9.1852.5P

ec C u0.4-9.1852.5P

κ0.071739

ec C u2.5P

0.4-9.185NTN

Bearing Technical Calculation Tool Usage Method

1-7. Appendix tables
Appendix table 1. Limiting dimensional tolerance of bearing inner dia.
Bearing inner dia. (d)mmMore than
0.6
18
30
50
80
120
150
180
250
315
400
500
630
800
1000
1250
1600

or less
18
30
50
80
120
150
180
250
315
400
500
630
800
1000
1250
1600
2000

JIS Class 0
μm
Upper
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

Lower
−8
−10
−12
−15
−20
−25
−25
−30
−35
−40
−45
−50
−75
−100
−125
−160
−200

JIS Class 6
μm
Upper
0
0
0
0
0
0
0
0
0
0
0
0
—
—
—
—
—

JIS Class 5
μm

Lower
−7
−8
−10
−12
−15
−18
−18
−22
−25
−30
−35
−40
—
—
—
—
—

Upper
0
0
0
0
0
0
0
0
0
0
—
—
—
—
—
—
—

Lower
−5
−6
−8
−9
−10
−13
−13
−15
−18
−23
—
—
—
—
—
—
—

JIS Class 4
μm
Upper
0
0
0
0
0
0
0
0
—
—
—
—
—
—
—
—
—

Lower
−4
−5
−6
−7
−8
−10
−10
−12
—
—
—
—
—
—
—
—
—

JIS Class 2
μm
Upper
0
0
0
0
0
0
0
0
—
—
—
—
—
—
—
—
—

Lower
−2.5
−2.5
−2.5
−4
−5
−7
−7
−8
—
—
—
—
—
—
—
—
—

Appendix table 2. Limiting dimensional tolerance of bearing outer dia.
Bearing outer dia. (D)mmMore than
2.5
18
30
50
80
120
150
180
250
315
400
500
630
800
1000
1250
1600
2000

or less
18
30
50
80
120
150
180
250
315
400
500
630
800
1000
1250
1600
2000
2500

JIS Class 0
μm
Upper
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

Lower
−8
−9
−11
−13
−15
−18
−25
−30
−35
−40
−45
−50
−75
−100
−125
−160
−200
−250

JIS Class 6
μm
Upper
0
0
0
0
0
0
0
0
0
0
0
0
0
0
—
—
—
—

JIS Class 5
μm

Lower
−7
−8
−9
−11
−13
−15
−18
−20
−25
−28
−33
−38
−45
−60
—
—
—
—

Upper
0
0
0
0
0
0
0
0
0
0
0
0
0
—
—
—
—
—

56／62

Lower
−5
−6
−7
−9
−10
−11
−13
−15
−18
−20
−23
−28
−35
—
—
—
—
—

JIS Class 4
μm
Upper
0
0
0
0
0
0
0
0
0
0
—
—
—
—
—
—
—
—

Lower
−4
−5
−6
−7
−8
−9
−10
−11
−13
−15
—
—
—
—
—
—
—
—

JIS Class 2
μm
Upper
0
0
0
0
0
0
0
0
0
0
—
—
—
—
—
—
—
—

Lower
−2.5
−4
−4
−4
−5
−5
−7
−8
−8
−10
—
—
—
—
—
—
—
—

NTN

Bearing Technical Calculation Tool Usage Method

Appendix table 3. Radial internal clearance of deep groove ball brgs.
Bearing inner dia. (d)mmMore than or less
10
6
18
10
24
18
30
24
40
30
50
40
65
50
80
65
100
80
120
100
140
120
160
140
180
160
200
180
225
200
250
225
280
250
315
280
355
315
400
355
450
400
500
450
560
500
630
560

min
0
0
0
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
3
3
3
3
10
10

C2
μm

max
7
9
10
11
11
11
15
15
18
20
23
23
25
30
35
40
45
55
60
70
80
90
100
110

min
2
3
5
5
6
6
8
10
12
15
18
18
20
25
25
30
35
40
45
55
60
70
80
90

CN
μm

max
13
18
20
20
20
23
28
30
36
41
48
53
61
71
85
95
105
115
125
145
170
190
210
230

min
8
11
13
13
15
18
23
25
30
36
41
46
53
63
75
85
90
100
110
130
150
170
190
210

C3
μm

max
23
25
28
28
33
36
43
51
58
66
81
91
102
117
140
160
170
190
210
240
270
300
330
360

min
14
18
20
23
28
30
38
46
53
61
71
81
91
107
125
145
155
175
195
225
250
280
310
340

C4
μm

max
29
33
36
41
46
51
61
71
84
97
114
130
147
163
195
225
245
270
300
340
380
420
470
520

min
20
25
28
30
40
45
55
65
75
90
105
120
135
150
175
205
225
245
275
315
350
390
440
490

C5
μm

max
37
45
48
53
64
73
90
105
120
140
160
180
200
230
265
300
340
370
410
460
510
570
630
690

Appendix table 4. Radial internal clearance of cylindrical roller brgs.
Bearing inner dia. (d)mmMore than or less
24
10
30
24
40
30
50
40
65
50
80
65
100
80
120
100
140
120
160
140
180
160
200
180
225
200
250
225
280
250
315
280
355
315
400
355
450
400
500
450

min
0
0
5
5
10
10
15
15
15
20
25
35
45
45
55
55
65
100
110
110

C2
μm

max
25
25
30
35
40
45
50
55
60
70
75
90
105
110
125
130
145
190
210
220

min
20
20
25
30
40
40
50
50
60
70
75
90
105
110
125
130
145
190
210
220

CN
μm

max
45
45
50
60
70
75
85
90
105
120
125
145
165
175
195
205
225
280
310
330

min
35
35
45
50
60
65
75
85
100
115
120
140
160
170
190
200
225
280
310
330

57／62

C3
μm

max
60
60
70
80
90
100
110
125
145
165
170
195
220
235
260
275
305
370
410
440

min
50
50
60
70
80
90
105
125
145
165
170
195
220
235
260
275
305
370
410
440

C4
μm

max
75
75
85
100
110
125
140
165
190
215
220
250
280
300
330
350
385
460
510
550

min
65
70
80
95
110
130
155
180
200
225
250
275
305
330
370
410
455
510
565
625

C5
μm

max
90
95
105
125
140
165
190
220
245
275
300
330
365
395
440
485
535
600
665
735

NTN

Bearing Technical Calculation Tool Usage Method

Appendix table 5. Radial internal clearance of spherical roller brgs.
Bearing inner dia. (d)mmMore than or less
24
14
30
24
40
30
50
40
65
50
80
65
100
80
120
100
140
120
160
140
180
160
200
180
225
200
250
225
280
250
315
280
355
315
400
355
450
400
500
450
560
500
630
560
710
630
800
710
900
800
1000
900
1120
1000
1250
1120
1400
1250

min
10
15
15
20
20
30
35
40
50
60
65
70
80
90
100
110
120
130
140
140
150
170
190
210
230
260
290
320
350

C2
μm

max
20
25
30
35
40
50
60
75
95
110
120
130
140
150
170
190
200
220
240
260
280
310
350
390
430
480
530
580
640

min
20
25
30
35
40
50
60
75
95
110
120
130
140
150
170
190
200
220
240
260
280
310
350
390
430
480
530
580
640

CN
μm

max
35
40
45
55
65
80
100
120
145
170
180
200
220
240
260
280
310
340
370
410
440
480
530
580
650
710
780
860
950

max
35
40
45
55
65
80
100
120
145
170
180
200
220
240
260
280
310
340
370
410
440
480
530
580
650
710
780
860
950

C3
μm

max
45
55
60
75
90
110
135
160
190
220
240
260
290
320
350
370
410
450
500
550
600
650
700
770
860
930
1020
1120
1240

min
45
55
60
75
90
110
135
160
190
220
240
260
290
320
350
370
410
450
500
550
600
650
700
770
860
930
1020
1120
1240

C4
μm

max
60
75
80
100
120
145
180
210
240
280
310
340
380
420
460
500
550
600
660
720
780
850
920
1010
1120
1220
1330
1460
1620

min
60
75
80
100
120
145
180
210
240
280
310
340
380
420
460
500
550
600
660
720
780
850
920
1010
1120
1220
1330
1460
1620

C5
μm

max
75
95
100
125
150
180
225
260
300
350
390
430
470
520
570
630
690
750
820
900
1000
1100
1190
1300
1440
1570
1720
1870
2080

Appendix table 6. Limiting dimensional tolerance of shaft (1)Diameter
d6
e6
f6
g5
g6
classification
m
m
m
m
m
mm
More than or less Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower
−11
−14
−5
−5
−22
−13
−34
−25
−49
−40
10
6
−14
−17
−6
−6
−27
−16
−43
−32
−61
−50
18
10
−16
−20
−7
−7
−33
−20
−53
−40
−78
−65
30
18
−20
−25
−9
−9
−41
−25
−66
−50
−96
−80
50
30
−23
−29
−10
−10
−49
−30
−79
−60
−119
−100
80
50
−27
−34
−12
−12
−58
−36
−94
−72
−120 −142
120
80
−32
−39
−14
−14
−68
−43
−110
−85
−145 −170
180
120
−35
−44
−15
−15
−79
−50
−170 −199 −100 −129
250
180
−40
−49
−17
−17
−88
−56
−110 −142−190 −222
315
250
−43
−54
−18
−18
−98
−62
−210 −246 −125 −161
400
315
−47
−60
−20
−20
−68 −108−230 −270 −135 −175
500
400
—
—
−66
−22
−76 −120−260 −304 −145 −189
630
500
—
—
−74
−24
−80 −130−290 −340 −160 −210
800
630
—
—
−82
−26
−86 −142−320 −376 −170 −226
800 1000
—
—
−94
−28
−98 −164−350 −416 −195 −261
1000 1250
—
—
−108
−30
−110 −188−390 −468 −220 −298
1250 1600

58／62

h5
m

h6
m

Upper Lower
0
−6
0
−8
0
−9
0
−11
0
−13
0
−15
0
−18
0
−20
0
−23
0
−25
0
−27
—
—
—
—
—
—
—
—
—
—

Upper Lower
0
−9
0
−11
0
−13
0
−16
0
−19
0
−22
0
−25
0
−29
0
−32
0
−36
0
−40
0
−44
0
−50
0
−56
0
−66
0
−78

NTN

Bearing Technical Calculation Tool Usage Method

Appendix table 7. Limiting dimensional tolerance of shaft (2)Diameter
h7
h8
h9
h10
j5
js5
j6
classification
μm
μm
μm
μm
μm
μm
μm
mm
More than or less Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower
7
−2
−3
3
−2
−58
−36
−22
−15
4
0
0
0
0
10
6
8
−3
−4
4
−3
−70
−43
−27
−18
5
0
0
0
0
18
10
9
−4
−4.5
4.5
−4
−84
−52
−33
−21
5
0
0
0
0
30
18
11
−5
−5.5
5.5
−5
−100
−62
−39
−25
6
0
0
0
0
50
30
12
−7
−6.5
6.5
−7
−120
−74
−46
−30
6
0
0
0
0
80
50
13
−9
−7.5
7.5
−9
−140
−87
−54
−35
6
0
0
0
0
120
80
14
−11
−9
9
−11
−160
−100
−63
−40
7
0
0
0
0
180
120
16
−13
−10
10
−13
−185
−115
−72
−46
7
0
0
0
0
250
180
16
−16
−11.5
11.5
−16
−210
−130
−81
−52
7
0
0
0
0
315
250
18
−18
−12.5
12.5
−18
−230
−140
−89
−57
7
0
0
0
0
400
315
20
−20
−13.5
13.5
−20
−250
−155
−97
−63
7
0
0
0
0
500
400
—
—
—
—
—
—
−280
−175
−110
−70
0
0
0
0
630
500
—
—
—
—
—
—
−320
−200
−125
−80
0
0
0
0
800
630
—
—
—
—
—
—
−360
−230
−140
−90
0
0
0
0
800 1000
—
—
—
—
—
—
−420
−260
−165
−105
0
0
0
0
1000 1250
—
—
—
—
—
—
−500
−310
−195
−125
0
0
0
0
1250 1600

Appendix table 8. Limiting dimensional tolerance of shaft (3)Diameterclassification
mmMore than or less
10
6
18
10
30
18
50
30
80
50
120
80
180
120
250
180
315
250
400
315
500
400
630
500
800
630
1000
800
1250
1000
1600
1250

js6
μm
Upper Lower
−4.5
4.5
−5.5
5.5
−6.5
6.5
−8
8
−9.5
9.5
−11
11
12.5 −12.5
14.5 −14.5
−16
16
−18
18
−20
20
−22
22
−25
25
−28
28
−33
33
−39
39

j7
k5
k6
k7
m5
m6
μm
μm
μm
μm
μm
μm
Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower
6
12
6
15
16
10
1
1
1
−5
7
10
7
15
7
18
19
12
1
1
1
−6
9
12
8
17
8
21
23
15
2
2
2
−8
11
13
9
20
9
25
27
18
2
2
2
−10
13
15
11
24
11
30
32
21
2
2
2
−12
15
18
13
28
13
35
38
25
3
3
3
−15
18
20
15
33
15
40
43
28
3
3
3
−18
21
22
17
37
17
46
50
33
4
4
4
−21
24
25
20
43
20
52
56
36
4
4
4
−26
27
26
21
46
21
57
61
40
4
4
4
−28
29
29
23
50
23
63
68
45
5
5
5
−32
32
31
26
—
—
—
—
70
—
—
70
44
0
0
30
—
—
—
—
80
—
—
80
50
0
0
34
—
—
—
—
90
—
—
90
56
0
0
40
—
—
—
—
106
—
—
105
66
0
0
48
—
—
—
—
126
—
—
125
78
0
0

59／62

NTN

Bearing Technical Calculation Tool Usage Method

Appendix table 9. Limiting dimensional tolerance of shaft (4)Diameterclassification
mmMore than or less
10
6
18
10
30
18
50
30
65
50
80
65
100
80
120
100
140
120
160
140
180
160
200
180
225
200
250
225
280
250
315
280
355
315
400
355
450
400
500
450
560
500
630
560
710
630
800
710
900
800
1000
900
1120
1000
1250
1120
1400
1250
1600
1400

Upper
19
23
28
33

n6
μm

p6
μm

Lower
10
12
15
17

Upper
24
29
35
42

Lower
15
18
22
26

39

20

51

32

45

23

59

37

52

27

68

43

60

31

79

50

66

34

88

56

73

37

98

62

80

40

108

68

88

44

122

78

100

50

138

88

112

56

156

100

132

66

186

120

156

78

218

140

Upper
28
34
41
50
60
62
73
76
88
90
93
106
109
113
126
130
144
150
166
172
194
199
225
235
266
276
316
326
378
408

r6
μm

Lower
19
23
28
34
41
43
51
54
63
65
68
77
80
84
94
98
108
114
126
132
150
155
175
185
210
220
250
260
300
330

Upper
34
41
49
59
71
73
86
89
103
105
108
123
126
130
146
150
165
171
189
195
220
225
255
265
300
310
355
365
425
455

r7
μm

Lower
19
23
28
34
41
43
51
54
63
65
68
77
80
84
94
98
108
114
126
132
150
155
175
185
210
220
250
260
300
330

Appendix table 10. Limiting dimensional tolerance of housing hole (1)Diameterclassification
mmMore than or less
18
10
30
18
50
30
80
50
120
80
180
120
250
180
315
250
400
315
500
400
630
500
800
630
800 1000
1000 1250
1250 1600
1600 2000

E6
μm

F6
μm

Upper Lower Upper Lower
16
27
32
43
20
33
40
53
25
41
50
66
30
49
60
79
36
58
72
94
43
68
85
110
50
79
100
129
56
88
110
142
62
98
125
161
68
108
135
175
76
120
145
189
80
130
160
210
86
142
170
226
98
164
195
261
110
188
220
298
120
212
240
332

F7
μm

G6
μm

G7
μm

Upper Lower Upper Lower Upper
6
24
17
34
16
7
28
20
41
20
9
34
25
50
25
10
40
29
60
30
12
47
34
71
36
14
54
39
83
43
15
61
44
96
50
17
69
49
108
56
18
75
54
119
62
20
83
60
131
68
22
92
66
146
76
24
104
74
160
80
26
116
82
176
86
28
133
94
203
98
30
155
108
235
110
32
182
124
270
120

60／62

H6
μm

Lower Upper Lower
0
11
6
0
13
7
0
16
9
0
19
10
0
22
12
0
25
14
0
29
15
0
32
17
0
36
18
0
40
20
0
44
22
0
50
24
0
56
26
0
66
28
0
78
30
0
92
32

NTN

Bearing Technical Calculation Tool Usage Method

Appendix table 11. Limiting dimensional tolerance of housing hole (2)Diameter
H7
H8
J6
J7
JS6
JS7
classification
μm
μm
μm
μm
μm
μm
mm
More than or less Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower
0
0
−8
−5.5
−9
9
5.5
10
6
−5
27
18
18
10
0
0
−9
−6.5 10.5 −10.5
6.5
12
8
−5
33
21
30
18
0
0
−11
−8
12.5 −12.5
8
14
10
−6
39
25
50
30
0
0
−12
−9.5 15
−15
9.5
18
13
−6
46
30
80
50
0
0
−13
−11
17.5 −17.5
11
22
16
−6
54
35
120
80
0
0
−14
−12.5 20
−20
12.5
26
18
−7
63
40
180
120
0
0
−16
−14.5 23
−23
14.5
30
22
−7
72
46
250
180
0
0
−16
−16
−26
26
16
36
25
−7
81
52
315
250
0
0
−18
−18
28.5 −28.5
18
39
29
−7
89
57
400
315
0
0
−20
−20
31.5 −31.5
20
43
33
−7
97
63
500
400
0
0
−22
−35
35
22
110
70
630
500
—
—
—
—
0
0
−25
−40
40
25
125
80
800
630
—
—
—
—
0
0
−28
−45
45
28
140
90
800 1000
—
—
—
—
0
0
−33
52.5 −52.5
33
165
105
1000 1250
—
—
—
—
0
0
−39
62.5 −62.5
39
195
125
1250 1600
—
—
—
—
0
0
−46
−75
75
46
230
150
1600 2000————

Appendix table 12. Limiting dimensional tolerance of housing hole (3)Diameter
K5
K6
K7
M5
M6
M7
classification
μm
μm
μm
μm
μm
μm
mm
More than or less Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower
0
−15
−9
−6
−4
−12
−12
−18
−4
6
2
2
18
10
0
−17
−11
−8
−4
−14
−15
−21
−5
6
2
1
30
18
0
−20
−13
−9
−4
−16
−18
−25
−5
7
3
2
50
30
0
−24
−15
−10
−5
−19
−21
−30
−6
9
4
3
80
50
0
−28
−18
−13
−6
−23
−25
−35
−8
10
4
2
120
80
0
−33
−21
−15
−8
−27
−28
−40
−9
12
4
3
180
120
0
−37
−24
−18
−8
−31
−33
−46
−11
13
5
2
250
180
0
−41
−27
−20
−9
−36
−36
−52
−13
16
5
3
315
250
0
−46
−29
−22
−10
−39
−40
−57
−14
17
7
3
400
315
0
−50
−32
−25
−10
−43
−45
−63
−16
18
8
2
500
400
−26
−70
−44
−26
−70
−96
0
0
630
500
—
—
—
—
−30
−80
−50
−30
−80
−100
0
0
800
630
—
—
—
—
−34
−90
−56
−34
−90
−124
0
0
800 1000
—
—
—
—
−40
−106
−66
−40
−105
−145
0
0
1000 1250
—
—
—
—
−48
−126
−78
−48
−125
−173
0
0
1250 1600
—
—
—
—
−58
−150
−92
−58
−150
−208
0
0
1600 2000
—
—
—
—

61／62

NTN

Bearing Technical Calculation Tool Usage Method

Appendix table 13. Limiting dimensional tolerance of housing hole (4)DiameterN5N6classificationμm
μm
mmMore than or less Upper Lower Upper Lower
−20
−17
−9
−9
18
10
−24
−21
−11
−12
30
18
−28
−24
−12
−13
50
30
−33
−28
−14
−15
80
50
−38
−33
−16
−18
120
80
−45
−39
−20
−21
180
120
−51
−45
−22
−25
250
180
−57
−50
−25
−27
315
250
−62
−55
−26
−30
400
315
−67
−60
−27
−33
500
400
−88
−44
630
500
—
—
−100
−50
800
630
—
—
−112
−56
800 1000
—
—
−132
−66
1000 1250
—
—
−156
−78
1250 1600
—
—
−184
−92
1600 2000
—
—

N7
μm

P6
μm

P7
μm

Upper Lower Upper Lower Upper
−23
−11
−26
−15
−5
−28
−14
−31
−18
−7
−33
−17
−37
−21
−8
−39
−21
−45
−26
−9
−45
−24
−52
−30
−10
−52
−28
−61
−36
−12
−60
−33
−70
−41
−14
−66
−36
−79
−47
−14
−73
−41
−87
−51
−16
−80
−45
−95
−55
−17
−114
−78
−78 −122
−44
−130
−88
−88 −138−50−146 −100 −156−100
−56−171 −120 −186
−120
−66−203 −140 −213
−140−78−242 −170 −262
−170
−92

Lower
−29
−35
−42
−51
−59
−68
−79
−88
−98
−108
−148
−168
−190
−225
−265
−320

Appendix table 14. Material physical property value
Material

Young's modulus
2
MPa {kgf/mm }Poisson's ratio

Bearing steels
Carbon steels
Cast ironSpheroidal graphite iron castings
Aluminium
Martensitic stainless steels
Austenitic stainless steels
Copper208000 {21200}
198900 {20300}
100500 {10250}
150900 {15400}
68940 {7030}
199900 {20400}
196500 {20050}
131000 {13370}

0.3
0.3
0.3
0.3
0.34
0.3
0.3
0.35

Coefficient of linear
thermal expansion−6×10 （1/˚C）
12.5
10.23
10.5
10.0
21.5
17.1
17.1
16.5

Note) Poisson's ratio and the coefficient of linear thermal expansion are not affected by the input param. unit.

Appendix table 15. Reliability factor a1
Reliability %Ln

Reliability factor

90
95
96
97
98
99
99.2
99.4
99.6
99.8
99.9
99.92
99.94
99.95

L10
L5
L4
L3
L2
L1
L0.8
L0.6
L0.4
L0.2
L0.1
L0.08
L0.06
L0.05

1
0.64
0.55
0.47
0.37
0.25
0.22
0.19
0.16
0.12
0.093
0.087
0.080
0.077

a1

Appendix table 16. Value of contamination factor ec
Contamination levelec
Dpw <100mm

Dpw ≥100mm

1

1High cleanliness
Oil filtered by an extremely fine filter, standard
grease sealed bearings and seal bearings

0.8〜0.6

0.9〜0.8

Standard cleanliness
Oil filtered by a fine filter, standard grease sealed
bearings and shielded bearings

0.6〜0.5

0.8〜0.6

Light contamination
The lubricant is slightly contaminated

0.5〜0.3

0.6〜0.4

Normal contamination
No sealing, rough filter is used, abrasion powder, environment
in which particles enter from the periphery

0.3〜0.1

0.4〜0.2

Heavy contamination
Significantly contaminated surrounding environment, and astate in which sealing performance of bearings is insufficient

0.1〜0

0.1〜0

0

0

Extremely high cleanlinessParticle size about the same as the oil film thicknessof lubricant, and laboratory level environment

Extreme contamination

62／62