KOYO

Koyo (JTEKT) Bearings

Koyo (JTEKT) is one of the high-volume manufacturers of standard deep groove ball bearings; its catalogs cover the complete 6000/6200/6300/6800/6900/16000 series. What sets Koyo apart is the wide variety of its seal designations: contact seal 2RS, very light contact seal 2RD, non-contact seal 2RU and metal shield ZZ are each coded separately; in addition, the special CM clearance code for electric motors (as in 6205ZZCM) is very widely used on the market instead of CN.

Japan (headquartered in Nagoya/Osaka). Production also takes place at plants in France, the Czech Republic, Romania, the USA, China, India, Thailand and Indonesia; the country name on the bearing varies according to the plant where it was made.

Code structure

There is a SINGLE SPACE between the basic designation and the seal/shield code; subsequent suffixes follow directly with no space. Examples: 6205 ZZ, 6205 ZZCM, 6205 2RSC3, 6205 2RSC3FG. In the laser marking on the bearing and in dealer lists, the same code may appear with no spaces at all: 6205ZZ, 62052RSC3

Suffix	Meaning	Example
Z	Fixed metal shield on one side, other side open	6205 Z
ZZ	Fixed metal shields on both sides – Koyo's standard shielded type (equivalent to SKF 2Z, NSK ZZ, FAG 2ZR)	6205 ZZ
ZX	Removable (detachable) metal shield on one side	6205 ZX
ZZX	Removable metal shields on both sides	6205 ZZX
RS	Synthetic rubber (NBR) contact seal on one side, other side open	6205 RS
2RS	Steel-reinforced NBR contact seals on both sides – Koyo's standard sealed type (equivalent to SKF 2RS1, FAG 2RSR, NSK DDU, NTN LLU)	6205 2RS
RK	Contact seal on one side (RK profile type, seal geometry differs from RS)	6205 RK
2RK	Contact seals on both sides (RK profile type)	6205 2RK
U	Contact seal on one side (U type, mainly small/miniature series)	6205 U
UU	Contact seals on both sides (U type, mainly small/miniature series)	6205 UU
RD	Very light-contact seal on one side – low friction, lower torque than RS	6205 RD
2RD	Very light-contact seals on both sides – low-friction sealed type (similar in principle to SKF 2RSL / NSK DDW)	6205 2RD
RU	Non-contact (labyrinth gap) rubber seal on one side – frictionless, high speed	6205 RU
2RU	Non-contact rubber seals on both sides (equivalent to NSK VV, NTN LLB) – high speed, low friction	6205 2RU
ZU	Non-contact seal on one side (ZU type)	6205 ZU
2ZU	Non-contact seals on both sides (ZU type)	6205 2ZU

Markings on the bearing: On shielded types (Z/ZZ), the marking is printed/embossed on the metal shield: "KOYO" on the top line, the full code below it (e.g. "6205ZZCM") and, usually on the same face or on the outer ring side face, the country name ("JAPAN", also FRANCE / CZECH / CHINA / INDIA / THAILAND / U.S.A.). On rubber-sealed types (RS/2RS/2RD/2RU), the brand and code are printed on the sheet-metal-reinforced face of the seal; on open types, "KOYO 6205 JAPAN" is laser-marked on the outer ring side face. The code is usually written as a single string with no spaces (as in 62052RSC3). There is also a production lot/date code made up of small letters/digits. On some batches of recent production, the marking "JTEKT" may also appear.