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Installation of covered bearing unit

Fig. 12
Fig. 13
Fig. 14

For covered bearing units, selecting the shaft and fitting the shaft and bearing housing are identical with those for the standard bearing units. The cover can be easily fitted without any special tool or jig.

Installation procedure of cover

  1. Remove the steel plate cover from the bearing unit. The cover can be easily removed with hands. If it cannot be easily removed, use a screwdriver as shown in Fig. 12.
  2. To enhance dust and moisture resistance, completely fill the area between the two lips of the rubber seal in the cover with grease. Also, put grease into the cover inside space, to approx. 2/3 its volume (apply cup grease unless otherwise specified) (Fig. 13).
  3. Chamfer the shaft end to protect the lips of the rubber seal against possible damage. Then, fit the greased cover over the shaft. To do so, fit the inner ring to the shaft, and then tighten the mounting bolts of the housing. Recommended torques for tightening hex. head bolt. The installation procedure sequence may be reversed for convenience in installation (first, tighten the mounting bolts of the housing, and then fit the inner ring to the shaft).
  4. Fit the cover that is fitted over the shaft, into the spigot of the bearing housing. When fitting the cover, NEVER directly hit it with a steel hammer. First, place a block, made of synthetic resin or wood, over the cover. Then, from 45°direction, tap it with a hammer around the circumference of the cover to exert a uniform impact on the cover to fit it into the groove on the bearing housing (Fig. 14). Fasten the cast iron cover with three set bolts.
  5. Put grease in the other cover in a manner similar to step 2), and fit the cover over the shaft. If the cover is a closed type, put some grease in advance in the spigot section of the bearing housing (Fig. 13).
  6. Fit the cover that is fitted over the shaft into the spigot of the bearing housing, in a manner similar to step 4) (Fig. 14).

Steel plate cover designed for easy installation and removal

  1. NTN steel plate covered unit has a cover fitting groove as illustrated below (Fig. 15). Fit the cover in the cover fitting groove and tap it with a synthetic resin or wooden hammer from a 45° direction. Then, the cover is securely fitted by reaction force (Fig. 16) (note that #204 is a press-fitted type).
  2. For easy removal of the cover, a groove is cut on the outer side of the cover. When removing the cover, fit a flatblade screwdriver into this groove, and then pry the cover to remove it. Other manufacturers' bearing covers are all press-fitted, making fitting and removal of covers difficult.
Fig. 15   Fig. 16