CAT 271-6890 Single Row Taper Roller Bearing

CAT 271-6890 (2716890) is a Caterpillar single-row tapered roller bearing assembly, suitable for heavy-duty transmission components such as the gearbox axle and drive axle differential of CAT excavators and loaders. It is used to withstand combined radial and unidirectional axial loads. The following is the core technical information:

Core Technical Parameters
Item Details
Part Model: CAT 271-6890 (2716890) Single-row tapered roller bearing assembly (including inner ring/outer ring/rollers/cage, suitable for heavy-duty transmission conditions)

Core Materials: Inner ring/outer ring: SAE 52100 bearing-grade alloy carburized steel, carburized and quenched, hardened layer depth 1.0–1.4 mm, hardness HRC 60–64; Rollers: Chromium steel (GCr15), surface Ra≤0.4 μm; Cage: Stamped low-carbon steel, anti-roller misalignment

Key Dimensions: Inner diameter 100 mm, outer diameter… 180 mm in diameter, 46 mm in width, 10° raceway taper angle, suitable for 100 mm journal (tolerance h6, 0–-0.035 mm), 1:12 taper with outer ring, 0.012–0.028 mm interference fit. Weight: Approx. 5.2 kg. Compatible with CAT 320D2/323D2 excavators (slewing gearbox input shaft), 972M loaders (gearbox second shaft), and D6T bulldozers (drive axle differential). Used for heavy-duty transmission systems, suitable for combined radial and unidirectional axial loads. Operating conditions: Dynamic radial load 280 kN, limiting speed 2800 rpm, operating temperature -30℃ to +150℃, compatible with extreme pressure lithium-based grease (NLGI 2). Core functions and structural features: Separable structure: The inner and outer rings are separable, facilitating installation, disassembly, and maintenance, suitable for transmission parts with limited space. **Conical Load Distribution:** A 10° raceway cone angle evenly distributes radial and axial loads, reducing localized stress concentration and improving fatigue resistance.

**Interference Fit Fixing:** The inner diameter and journal are interference-fitted by 0.012–0.028 mm, ensuring torque transmission without slippage, guaranteeing transmission accuracy, and reducing vibration and noise.

**High-Precision Cage:** The stamped steel cage has uniform spacing and precise roller positioning, suppressing misalignment and extending bearing assembly life.

**Installation and Maintenance Points:**
**Installation Specifications:** Clean the journal and bearing housing. Journal surface Ra≤0.8 μm, tolerance h6 (0–-0.035 mm), hardness HRC≥58; bearing housing tolerance H7, surface free of scratches and burrs.

Heat the inner ring (≤120℃) before assembly. Use a sleeve to press against the inner ring end face, applying force evenly to ensure tight contact with the shaft shoulder. For the outer ring, cold install and adjust the preload to the value in the model manual (e.g., 100–120 N・m for the 972M gearbox). Apply extreme pressure lithium-based grease, filling the bearing to 1/3–1/2 of its internal space to prevent heat buildup.

Maintenance Recommendations: Every 1000 operating hours, check for raceway wear, spalling, and burning. Replace immediately if the inner diameter clearance is >0.06 mm. Simultaneously check journal wear (>0.02 mm requires repair).

When replacing, prioritize genuine parts to avoid confusion with similar models such as 271-6891.

Simultaneously check the lubrication channels, clean impurities, and prevent abnormal wear.