Turntable Bearings and Lazy Bearings

TRAILER RINGS

Series U,L&N – Light duty trailer rings

Trailer ring technical

Trailer rings do not usually have hardened raceways and cannot be considered as a replacement for a slewing rings.

Trailer rings are not precision bearings and dimensions such as the overall height can vary by as much as 3mm, and diameters by as much as 5mm.

Series U

Suitable for light offroad trailers, irrigation systems or airport luggage trolleys at speeds < 25 km/h and simple industrial turntables

Series L

Suitable for light trailers at speeds < 30 km/h

Series N

Suitable for heavier farm vehicles, factory trailers and small road going trailers at speeds > 30 km/h.

Support structure

Trailer rings should be supported by a stiff frame over at least 50% of their surface area with the loading plug positioned away from the direction of any significant radial load, usually at 90 deg to the direction of travel. Metal tags welded to the frame can be used to improve radial location and reduce bolt shear stress caused by acceleration and deceleration.

Bolt data

Series U, L and N are supplied undrilled. 6 to 8 Grade 8.8 bolts size M12 to M16 (depending on diameter) should be added to each flange. Typical bolt patterns are illustrated in Figure 1. Bolt torques should be tightened appropriately and checked during a monthly maintenance cycle. Recommended bolt torques are tabulated in Table 1

Bolt size                    Recommended torque (Nm)

M12                                        78
M14                                       126

M16                                       193

Table 1: Recommended trailer ring bolt torques

Lubrication

Unsealed trailer rings must be fully greased on installation and throughout their service life. A good quality multipurpose EP2 grease will be adequate in most applications. Grease intervals are difficult to define and will depend on operating conditions. In dirty or wet environments continuous lubrication is preferable. Always rotate the ring during lubrication to distribute the grease throughout the raceway.