NTN in Mining: Which Bearings Are Used in Crushers, Mills, Screens and Conveyor Belts

Jaw and cone crushers subject bearings to very high combined loads, with impacts and constant vibration. NTN tapered roller bearings are designed to withstand simultaneous radial and axial loads, which is typical in these machines. Their internal geometry distributes contact pressure evenly, helping to extend service life under severe conditions. In gyratory and cone crushers, the main shaft and countershaft bearings are usually of this type.

In ball and rod mills, tapered roller bearings are used on trunnion supports and drive systems. Precise alignment and proper internal clearance are critical to avoid premature failure. When ordering a replacement, it is advisable to have the exact NTN code, for example 32920 or 32924, which correspond to frequently used metric series. It is also useful to measure the bore, outer diameter and width to verify equivalences.

A common mistake is choosing a bearing with standard internal clearance when the application requires C3 clearance, which is greater than normal, to absorb thermal expansion. Another is not respecting the tightening torque of the lock nuts, which can cause slippage on the shaft. Before requesting a quote, send a photo of the part with the engraved code and confirmed measurements. At MR we advise you as an official NTN distributor so that the replacement is the correct one.

NTN angular contact bearings are used in centrifugal pumps, electric motors and gearboxes that accompany mills and crushers. They support combined loads and allow adjustment of clearance or preload according to the mounting. In paired arrangements, they can absorb axial loads in both directions, which is necessary in vertical or horizontal shafts with thrust. Codes such as 7010 or 7210 are examples of angular contact bearings that MR quotes.

In mill lubrication systems, pumps often carry angular contact bearings on the drive shaft. Rotation speed and fluid temperature influence the selection of internal clearance and seal type. If the bearing operates in a dusty environment, it is recommended to use 2RS seals (rubber on both sides) to prevent contaminant ingress. In case of high temperatures, C3 clearance may be necessary to compensate for expansion.

When ordering these bearings, it is key to indicate whether they are mounted in pairs, tandem or back-to-back arrangement. It is also advisable to clarify whether the original equipment used a sheet metal, polyamide or machined cage. A frequent mistake is replacing a bearing with another with a different contact angle without verifying the resulting axial load. Send us the NTN code, for example 7011, and the working conditions to quote the appropriate option.

Mineral conveyor belts use insert bearings mounted in pillow block, take-up or flange housings. NTN Y-bearings have a spherical outer ring that allows self-alignment within the housing. This compensates for small shaft misalignments or structure deformations, very common in mining installations. The inner ring can be with set screws, eccentric or with adapter sleeve.

In idlers and tail pulleys, inserts work exposed to dust, moisture and variable loads. Seal choice is fundamental in abrasive environments. The housing must be robust and well anchored to avoid vibrations that damage the bearing. When quoting, indicate the insert and housing code, or send photos of both.

A common mistake is using an insert with set screw locking in applications with alternating loads, where an eccentric ring is preferable. Another is not verifying the fit between housing and insert: if it is loose, premature wear occurs. At MR we market NTN Y-bearings and compatible housings for mining conveyor belts. Give us the code, for example AS201 or AR210, and we quote the complete assembly.

NTN cylindrical roller bearings are used in mill, conveyor and crusher gearboxes where radial loads are very high. Their design allows the inner or outer ring to be removed separately, which facilitates maintenance on large equipment. NU series, such as NU416 or NU218, are typical in transmission shafts with high speed and load. They accommodate axial displacement of the shaft relative to the housing, which is useful for thermal expansion.

In high-power electric motors that drive mills, cylindrical roller bearings are combined with ball or angular contact bearings. The cylindrical roller bearing absorbs radial load, while the other bearing axially locates the shaft. When ordering a replacement, it is important to know whether the original bearing has a sheet metal, machined brass or polyamide cage. It is also necessary to verify whether the inner ring has a cylindrical or tapered bore.

A frequent mistake is mounting a cylindrical roller bearing with excessive interference on the shaft, which reduces internal clearance and can cause overheating. Another is not respecting the mounting direction when the rings are separable. Before quoting, send the NTN code, for example NU317, and the shaft and housing measurements. At MR we help you identify the correct bearing for your mining gearbox or motor.

Vibrating screens subject bearings to extreme loads, with high accelerations and orbital movements. NTN spherical roller bearings, such as 21317 or 21318, are self-aligning and withstand angular misalignments of the shaft. Their design with two rows of spherical rollers on a common spherical outer ring gives them high radial load capacity and some axial capacity. They are a common choice in exciters and screen shafts.

In these machines, lubrication is critical: special grease for high speed and temperature is recommended, with frequent relubrication. Internal clearance should be C3 or even C4 in some cases, to absorb expansions and shock loads. When ordering a replacement, it is key to indicate whether the bearing works on the fixed or free side of the shaft. It is also advisable to know whether the bore is cylindrical or tapered, since adapter sleeve mountings are used in screens.

A common mistake is replacing a spherical roller bearing with a rigid ball bearing to save cost, which leads to premature failures. Another is not checking radial clearance after mounting, especially in tapered bores. At MR we quote NTN spherical roller bearings for screens and other vibrating equipment. Send us the code, for example 21319, and the vibration conditions to quote the appropriate option.

NTN cam followers and support rollers are used in auxiliary mechanisms of mining plants, such as cams, linear guides and transport systems. They have a thick outer ring that can roll directly on a track or cam, supporting radial loads and, in some models, axial loads. They are mounted on a stud or fixed shaft, and their compact design saves space. In mining they appear in feeders, gates and sampling equipment.

When selecting a cam follower, the type of load, linear speed and environment must be considered. There are also versions with spherical outer ring to compensate for misalignments. When quoting, it is useful to send the NTN code and the mounting stud measurements, as well as a photo of the assembly.

A frequent mistake is not lubricating the internal bearing according to the maintenance plan. At MR we advise you on which NTN cam follower is suitable for your mining application. Give us the part data and we quote the exact replacement.

NTN needle roller bearings are used in reduction gearboxes, hydraulic pumps and feed mechanisms of mining equipment. Their reduced cross-section allows compact supports with high radial load capacity. They are available as complete bearings, needle cages or needle assemblies with thrust washers.

When ordering a needle roller bearing, it is essential to indicate whether the complete bearing, the cage alone or the assembly with thrust washers is needed. Shaft and housing measurements are critical, since needles work with very precise fits. It is also necessary to specify whether the bearing requires a seal or is lubricated by the central system.

A common mistake is mounting the needles without the correct radial clearance, which causes overheating and seizure. Another is not verifying the surface hardness of the shaft, which must be adequate for contact with the needles. At MR we market NTN needle roller bearings and components for mining maintenance. Send us the code or measurements and we quote the appropriate solution.