For drilling machinery7 applications JSC "MPZ" produces the bearings of the two following modification groups: small multi row angular contact ball bearings of 296700 series and big multi row angular contact thrust ball bearings of 128700,128700M series.
The bearings can sustain radial and axial load in both directions. They are meant for application in turbodrill supports and screw downhole motors. The bearings are designed to evenly distribute the load between all the ball rows during shifting of the inner ring kit.
The design of 128700 series bearings has the inner and outer ring raceways shaped as tapered bevels with 60°contact angle.
The advantage of the improved 128700M and 296700 series bearings is their enhanced basic load rating and service time. The load rating increase is attained due to lowering the contact voltages between the balls and the bearing rings' raceways: The contact voltages reduction is accounted for changing the raceways' profile and choosing the optimum correlation of the raceways' radiuses and the balls' diameters.
The bearings are delivered to the customer in the assembled condition using attachment devices. The attachment devices (washers, buckles) ensure the possibility of fitting a bearing onto the shaft without dismantling.
The bearings are manufactured according to the specified technical specifications that compliment GOST 520 and reflect the specific requirements for the drilling machinery bearings - specifically, dedicated rings and balls material providing the bearings' increased operational life.