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New Product
Development of ‘Highly Greased Ball Bearing’ with positive grease leakage prevention
March 31, 2010New Products

[For the first time in the bearing industry, high greasing and sealing performance is attained through use of a special cage shape!]

Photo : ‘Highly Greased Ball Bearing’

NTN Corporation (hereafter NTN) has developed and commercialized a ‘Highly Greased Ball Bearing’ with high sealing performance by controlling the grease behavior in the bearing with a special cage shape. This is the first time in the bearing industry that the grease fill of a bearing has been increased without leakage due to a special cage shape. Using this approach, bearing life is extended and depending on the operating conditions, the concept may also be applied to smaller bearings. This contributes to reductions in size, mass, and torque of equipment using these bearings.

Greased and sealed ball bearings are used in many applications because of the convenience of not needing an external lubrication system. To improve bearing lubrication life, use of a different kind of grease or an increase in the grease fill amount is a feasible approach. However, increasing the grease fill amount may cause marginal grease leakage depending on operating conditions, and the leaked grease may not only harm the bearing surroundings, but also cause adverse effects in the operation of the equipment. Therefore, the grease fill amount was previously chosen so that it was as high as possible without causing leakage.

Use of this cage allows for a limited increase in the grease fill amount without causing leakage. This acts to extend the grease life and in some cases, the bearing life. For example, in applications where the bearing load is relatively small and the bearing life is determined by the grease conditions, a highly greased smaller bearing may be substituted for a conventional bearing. This allows for reductions in size, mass, and torque of the equipment.

Mass production of the bearings using the cages mentioned above will begin for certain applications. These bearings will be marketed focusing on outer ring rotational applications. The bearing concept is the same but a plastic cage or a pressed steel cage will be used depending on the operating temperature.


  1. High greasing performance is attained through the changing of the cage configuration!
  2. Bearing life is extended by increasing the limited grease fill amount without causing leakage! (Grease life is doubled)
  3. Reductions in size, mass, and torque are achieved by downsizing the bearing. This is possible because of the extended grease life in these bearings!

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Product appearance photo

Product appearance photo

Cage photo (Pressed steel)

Photo : New cage

New cage

Photo : Standard cage

Standard cage