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Miniature & small ball bearings

Part Numbering System

The NMB part numbering system is comprised of the base part number and specification.
The NMB part numbering system is unique to MinebeaMitsumi. The JIS part numbering system is based on the identification system specified in JIS B 1513.

NMB Part Numbering

Model Name
Basic Symbols
Material Symbol Series Symbol Dimension Symbols
Details 3. Materials - -
Display example DD R- 1560
No display
SUJ 2 or equivalent bearing steel
DD
Martensitic stainless steel
CE
Outer/Inner ring :
SUJ2 or equivalent bearing steel
Ball :Ceramic

■Radial ball bearings (metric)

R-(RF-) Thick type (with flange)
L-(LF-) Thin type (with flange)
A- Ultra Thin Type
RNR- Thick type with snap ring
LNR- Thin Type with snap ring
■Radial ball bearings (inch)
RI- All inch types
(R-) * Used for some inch types
RIF- Flange type
■Thrust ball bearings
T-
■Special Type
AS- Special shape
Outer diameter - inner diameter dimensions are listed.
Ex) Metric size
1560 outer diameter: 15mm
inner diameter: 6mm
Ex) Inch size
418 outer diameter: 4/16 inch
inner diameter: 1/8 inch
X Internal design symbol Displayed after the basic symbol when there is a difference in internal design between the basic symbols.
Ex) 1560X2
Outer diameter: 15 mm
Inner diameter: 6 mm
Internal design X2 type
Model Name
Auxiliary Symbol
Shield and Seal Symbols Noise and Special Symbols Retainer Symbols
Details4.Shields,Seals - Details 5. Retainer
ZZ MT R
No display Open type
Z Steel plate shield
(Fixed with snap ring)
H (Pressed)  Steel plate shield
K (Staked)  Steel plate shield
S Rubber seal, non-contact type
D Rubber seal, contact type
When mounting on both sides, they are displayed on top of each other.
Ex) ZZ, DD, etc.
MT Low-noise motor specification
SD Special design specification
W Wider than standard
Y Narrower than standard
R Ribbon retainer(steel plate)
H Crown retainer(steel plate)
MN Resin retainer
(Polyamide  reinforced)

* Resin retainer is also available in other resin materials.
Specification name
Class symbol Clearance symbol Lubricant symbol Grease filling amount symbol
Details 7. Tolerances and Grades Details 9. Internal Clearance Details 18. Lubricants Details 18. Lubricants
P0 P25 LY121 L
Metric dimension series
P0 JIS Grade 0
P5 JIS Grade 5
Inch dimension series

A1

ABEC 1
A3 ABEC 3P
A5 ABEC 5P
Radial Clearance
P13 2.5μm ～ 7.5μm
P24 5.0μm ～ 10.0μm
P25 5.0μm ～ 12.5μm
P58 12.5μm ～ 20.0μm
* Display method
The lower and upper limits in the radial direction are displayed in inches.
Ex) Radial clearance
For 5.0 μm to 12.5 μm when converted to inches→ 0.0002 in to 0.0005 in 
Displayed using this number = "P25".
Lubricant type
LO Oil
LG Grease
LY Grease or Oil
LD No lubricant
No display Standard filling amount
25% to 35%
X 5% ～ 10%
L 10% ～ 15%
T 15% ～ 20%
H 40% ～ 50%
J 50% ～ 60%
Note 1 The filling amount is expressed as a percentage of the internal space volume.
Note 2 For some miniature
bearings, the filling amount may be adjusted.

NMB type display example 1


NMB type display example 2



JIS Part Numbering

Model Name
Basic Symbols
Material Symbol Series Symbol Inner Diameter Symbol
Details 3. Materials - -
Display example No display 60 8
No display
SUJ 2 or equivalent bearing steel
CE
Outer/Inner ring:
SUJ 3 or equivalent bearing steel
Ball : Ceramicx
60
62
63		 Single-row deep groove ball bearings

5

Inner diameter:5mm
6 Inner diameter:6mm
：

00

Inner diameter:10mm
01 Inner diameter:12mm

XInternal design symbol
Displayed after the basic symbol when there is a difference in internal design between the basic symbols.

Model Name
Auxiliary Symbol
Retainer Symbol Shield and Seal Symbol Special Symbol
Details 5. Retainer Details 4. Shields, Seals -
No display ZZ NR
No display Ribbon retainer
MN Resin retainer
(Polyamide reinforced)
* Resin retainer is also available in other resin materials.
No display Open type
Z Steel plate shield
S Rubber seal, non-contact type
D Rubber seal, contact type
When mounting on both sides, they are displayed on top of each other.
Ex) ZZ, DD, etc.
SD Special design specification
NR Type with snap ring
Specification name
Clearance symbol Sound symbol Class symbol Lubricant symbol Grease filling amount symbol
Details 9. Internal Clearance - Details 7. Tolerances and Grades Details 18. Lubricants Details 18. Lubricants
M3 MT P5 LY121 L

Radial Clearance

M2 3μm～8μm
M3 5μm～10μm
M4 8μm～13μm
M5 13μm～20μm
MT Low-noise motor specification
SM General specification
No display JIS Class 0
P5 JIS Class 5

Lubricant type

LO Oil
LG Grease
LY Grease or oil
LD No lubricant
No display Standard filling amount 25%~35%
X 5% ～ 10%
L 10% ～ 15%
T 15% ～ 20%
H 40% ～ 50%
J 50% ～ 60%
Note 1 The filling amount is expressed as a percentage of the internal space volume.

JIS Part Number

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