Koyo NATR8 track roller, 8 x 24 x 15 mm

These Koyo NATR yoke-type track rollers have caged needle rollers on an inner ring, with a crowned outer ring and two retaining end washers. 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. A crowned outer diameter alleviates uneven bearing loading caused by deflection, bending or misalignment in mounting.

The range has 4 sizes from 16 to 32 mm outside diameter. The NATR is non-separable: the two end washers are securely fastened to the inner ring and form effective labyrinth-type shields that help retain lubricant and exclude foreign material. A lubrication hole in the inner ring allows re-lubrication through a cross-drilled bolt or shaft that can be serviced from the end. 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
• Non-separable unit with two retaining end washers that act as labyrinth-type shields
• Lubrication hole in the inner ring for re-lubrication through a cross-drilled bolt or shaft
• Dynamic load rating as a track roller Cw 3.34 to 8.32 kN; basic dynamic load rating as a bearing C 4.62 to 10.2 kN
• Grease lubrication speed rating 8,100 to 13,000 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

The machine parts next to the track roller should be sized from the minimum clamping diameter da in the variant specification, so the end washers are adequately supported. Clamp the unit endwise between parallel faces, perpendicular to the axis, so the retaining washers cannot come off under load. If it cannot be clamped, a close axial fit in the yoke is needed.

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. Locate the lubrication hole in the inner ring in the unloaded zone of the raceway.

Related products

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