Koyo STO12 track roller, 12 x 32 x 12 mm

These Koyo STO yoke-type track rollers have caged needle rollers on a separable inner ring, with a crowned outer diameter. Track rollers, also known as cam followers, have thick-walled outer rings that run directly on a track. The thick outer rings give high load-carrying capability while keeping distortion and bending stresses low, and JTEKT designs them to withstand heavy rolling and shock loads on track-type or cam-controlled equipment. Yoke-type track rollers are designed for straddle mounting. A crowned outer diameter alleviates uneven bearing loading caused by deflection, bending or misalignment in mounting.

The range has 9 sizes from 19 to 72 mm outside diameter. They are supplied without end washers, so the outer ring must be guided by the adjacent end locating surfaces. With the inner ring removed, the STO becomes the RSTO series, which runs directly on a hardened and ground inner raceway. Koyo bearings are made by JTEKT Corporation.

Where this product is used

• Ram support rollers
• Material handling equipment
• Indexing equipment
• Track-type and cam-controlled equipment

Features

• Crowned outer diameter: alleviates uneven loading from deflection, bending or misalignment in mounting
• Caged needle rollers on a separable inner ring, supplied without end washers
• Dynamic load rating as a track roller Cw 4.15 to 25.2 kN; basic dynamic load rating as a bearing C 5.4 to 35.2 kN
• Grease lubrication speed rating 2,200 to 9,400 min-1 depending on size
• Thick-walled outer ring for high load capacity with low distortion and bending stress

Key specifications

Available sizes

Selecting the right option

Cw is the dynamic load rating as a track roller. For rating life (L10) calculations the applied radial load must not be greater than Cw/2 under ideal operating conditions of alignment, lubrication and temperature.

Fr perm is the maximum permissible dynamic radial load and F0r perm is the maximum permissible static radial load as a track roller. The F0r perm values give a minimum static factor fs of 0.7 for the worst internal load distribution, and they must not be exceeded, because exceeding them may cause permanent damage to the track roller.

The DZ suffix means cylindrical outer diameter, and a designation without DZ is crowned. Pick the one that suits your track.

Fitting and use

STO track rollers are supplied without end washers, so the outer ring must be guided by the adjacent end locating surfaces. The inner ring is separable.

Oil is the preferred lubricant for yoke-type track rollers. Use continuous oil lubrication or frequent grease lubrication for steady rotating conditions. Slow, intermittent oscillation is less critical and allows longer intervals between re-lubrication.

Related products

Also available from Koyo: the STO...DZ track roller range, the NATR track roller range and the NA22.2RS track roller range.