CAT 488-1644 Bearing-Aligning

CAT 488-1644 is a cage-enclosed needle roller bearing designed by Caterpillar for low-speed, heavy-duty rotating components such as gearbox planetary carriers and hydraulic motor output shafts. It is used for radial high-density load support and low-friction transmission, and is suitable for heavy-duty construction machinery power systems. The following is the structured core information:

Core Parameters
Item Details
Basic Information
Model 488-1644, cage-enclosed needle roller bearing, suitable for low-speed, heavy-duty conditions (≤1500rpm), only bears radial loads, installation method is interference fit (inner ring to shaft, outer ring to housing bore)

Compatible Models
Cat 320/323/326 excavators, 980/982 loaders, suitable for gearbox planetary carriers, hydraulic motor output shafts, drive axle differential half-shafts

Material and Process
Bearing steel (chromium steel GCr15), inner/outer ring hardened HRC 61-65, needle roller material same as bearing steel, cage is phenolic resin, surface uncoated, precision grade P6, Radial Clearance C2 Group
Key Dimensions: Inner diameter 50mm (1.969in), outer diameter 72mm (2.835in), width 22mm (0.866in), needle roller diameter 3.969mm, quantity 24 pieces, weight approx. 0.26kg
Functional Parameters: Radial dynamic load 42.8kN, radial static load 68.5kN, coefficient of friction ≤0.002 (oil lubrication), operating temperature -40℃ to +120℃, limiting speed 1800rpm (oil lubrication)
Compatible Components: Fits shaft diameter 50mm (h6 tolerance), fits bearing housing inner diameter 72mm (H7 tolerance), fits seal ring 4T-0521, mounting retaining ring 6V-0813, bolts 8T-4120 Installation and Maintenance Points
**Preparation Before Installation:** Clean the journal and bearing housing bore, removing burrs and oil stains; check the journal roundness to be ≤0.01mm, the inner ring interference fit to the shaft to be 0.015-0.025mm, and the outer ring interference fit to the housing bore to be 0.01-0.02mm; use dedicated press-fitting fixtures, and strictly prohibit striking the needle rollers and cage.

Installation Steps: Smoothly press the bearing into place using a hydraulic press (position the inner ring first, then press the outer ring); after press-fitting, check the end face runout to be ≤0.02mm, and the radial clearance to meet the C2 group requirements (0.008-0.018mm); after installation, add gear oil/hydraulic oil to ensure a sufficient oil film.

Maintenance and Replacement: Check the bearing condition every 1500 hours. Replace the bearing if abnormal noise occurs, temperature rise exceeds 65℃, or radial clearance exceeds 0.04mm. Avoid overload and uneven load, prevent fatigue damage to needle rollers and raceways, and change the lubricating oil regularly.