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Construction and Mining Machinery Business

Bearings for construction and mining machinery are used outdoors, which requires improved reliability for rugged environment use, extended life, and maintenance free. The construction and mining machinery bearings produced by NTN display high performance and reliability under extreme conditions, and contribute to safe and efficient workflow at construction, excavation, and transportation sites.

Main Construction Machinery Products

Photo: Main Construction Machinery Products

Wheel Bearings for Off-Highway Trucks

Photo: Wheel Bearings for Off-Highway Trucks

In addition to natural environments with a lot of sand clouds and dust, off-highway trucks are used in mines with very severe 24-hour duty cycles. In order to satisfy such market needs, NTN developed a high-functionality wheel bearing, an important part for the truck.

Market needs for wheel bearings and NTN new products

Diagram: Market needs for wheel bearings and NTN new products

Filter Seal Integrated Large-Sized Bearings

Wheel bearings require special measures against severe operating environments and improved reliability in addition to long life and maintenance-free operation. However, damage due to denting on the bearing raceways caused by dust, particles and metal abrasion powder from the gears around bearings contaminating lubricant is very common after only a short operation time.

The filter seal integrated large-sized bearing developed by NTN does not allow foreign objects in the lubricant to enter into bearings, resulting in longer life; therefore, it is expected that the intervals for replacing the bearings will be longer.

Filter seal integrated large-sized bearing
(tapered roller bearing)

Diagram: Filter seal integrated large size bearing (tapered roller bearing)

IC Tag Integrated Bearings

Off-highway trucks are periodically inspected and repaired. For critical components such as bearings, maintenance records such as inspection date and operating hours are managed and kept. Because bearings are used for a long time, it is challenging to simplify the management of them and to secure inspection records against loss. Thus, expectations were high for management using IC tags. However, existing IC tags do not allow reading or writing while embedded in metal and the use of non-magnetic material for enabling read/write operation makes the tag size too large. Therefore, IC tags have not been practical.

NTN has developed IC tag integrated bearings so that quality information and operation history can be directly recorded on the bearings. It is possible to read/write information on IC tags embedded directly in the bearings and to set management information for each user.

Photo: IC Tag Integrated BearingsIC Tag Integrated Bearings

Integrated Rotation Sensor Large-sized Bearings

As the off-highway trucks are driven on unpaved roads in the mines, slippage of wheels may cause accidents. As a countermeasure to avoid slippage, trucks are equipped with anti-lock brakes and traction control systems. These systems detect the rotation of the wheels to control them. The wheel rotation detection sensors are usually installed separately from the wheel bearings. In order to accurately detect the rotation speed, position adjustment is required for associated rotation sensor components.

NTN has developed an integrated rotation sensor large-sized bearing with a pulse detection sensor on the stationary inner ring, and a pulsar ring on the rotating outer ring. By integrating the rotation sensor and bearings, sensor positioning adjustment is not required and the number of components is reduced. In addition, a disconnection prevention mechanism is adopted for sensor wiring so that even when slippage occurs between the axle and bearing inner ring (called creep), rotational speed or direction can be detected without causing damage or errors to the sensor.

Photo: Diagram: Outer view of bearing