Cluster mill or Backing Bearings are multi-row cylindrical roller bearings and are used for 20-high reductions mills and rolling ferrous and non-ferrous materials. These bearings can have rollers that are cage guided or full complement depending on the loads and speeds of the application. A machined brass cage and sometimes a precision ground internal spacer is provided when the cage guided bearing is specified. The heavy section outer race and relatively smaller section inner race and rollers are closely matched to achieve precise section height specifications. The specifications allow for shaping of the backing assemblies to achieve the desired rolled material characteristics. These bearings are section numbered and serialized per specification for backing assembly building/roll shop tracking. They are available in popular backing bearing O.D. and sections heights that match mill size specifications.Backing bearings are specially developed for multi-roll cold rolling mills and are mainly used for high-precision rolling of steel and non-ferrous metal strip. Can also be used for other purposes, such as roller straightening machine or bending machines. Backing bearings are specially thick bearings on the outer ring and can be mounted on a static support shaft to form support rollers or straightening rollers. The force from the work roll is transmitted to the roll or stand by means of a support shaft and a support saddle system. Depending on the design, the backing bearings are able to withstand high radial loads, as well as the axial loads transmitted to the frame by adjacent mechanisms.

  structure

The structure of an outer ring without ribs, the first and second rows of rollers by the dual claw cage to guide the third column roller from a single row of the solid cage guide. The roller is guided axially by a movable collar on the inner ring. Such bearings for emulsion lubrication; structure two roller, outer ring has three ribs. The roller is guided by a double jaw brass retainer. This type of structure is suitable for all kinds of lubrication. According to the needs, can choose to seal or without sealing; structure three pairs of full-loaded type, inner ring, outer ring with a middle wall. This structure of the bearing without sealing, suitable for emulsion lubrication.

Section height grouping to ensure the accuracy of rolling plate, need to ensure high-precision bearings. Especially the beating of the outer ring and the bearing height tolerance of the cross section are the most important. This requires high machining accuracy and control of the tolerances of various components to achieve. LYHG back-up bearing section height tolerance is divided into seven groups, Ⅰ, Ⅱ, Ⅲ ... .. VIII, each 3μm or 5μm tolerance, as shown in Table 1:

Section Height Group Section Height Tolerance μm I 0 -0.005 II -0.005 -0.010 III -0.010 -0.015 Each set of backing bearings is marked with a section height group (Figure 4). The markings are located at the maximum wall thickness of the inner and outer rings (Figure 5). In order to reduce the inner ring wall thickness fluctuation, all the bearing inner ring mounted on the same shaft must be marked in the same position. All backing bearings on the same shaft must be the same tolerance group