CAT 7S-8670 RACE

CAT 7S-8670 is a Caterpillar original single-row tapered roller bearing outer ring, suitable for use in Cat 950GC loader transmissions, 140M grader rear axle differentials, 320D excavator slewing mechanisms, and other transmission components. It is used to position the outer ring of tapered roller bearings and bear radial and bidirectional axial loads. The following are the core technology and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model 7S-8670, type is single-row tapered roller bearing outer ring (compliant with ISO 355 standard), suitable for Cat 950GC loader transmission second axle tapered roller bearing outer ring, 140M grader rear axle differential bearing outer ring positioning, 320D excavator slewing bearing tapered roller bearing outer ring, C15 engine fan clutch bearing outer ring, material is SAE 52100 high carbon chromium bearing steel (hardened HRC 60-64), surface anodized black, operating temperature… -40℃ to +120℃, single weight approximately 2.3 kg (5.07 lb), suitable for grease/oil lubrication, radial dynamic load rating ≥125 kN, radial static load rating ≥150 kN, axial load ≥45 kN

Key Dimensions: Inner diameter 120 mm (tolerance H7, +0.040/0 mm), outer diameter 180 mm (tolerance g6, -0.010/-0.035 mm), width 35 mm (tolerance ±0.15 mm), cone angle α=12°30′, large end face chamfer r2=2 mm, small end face chamfer r1=1 mm, end face runout ≤0.01 mm, roundness ≤0.005 mm

Material and Manufacturing Process: 52100 Bearing steel forged blank, spheroidizing annealing → rough turning → finish turning → quenching (850-870℃ oil quenching) → tempering (180-200℃) → ultra-precision grinding (surface roughness Ra≤0.08 μm) → blackening oxidation (film thickness 5-8 μm), raceway hardness HRC 60-64, matrix hardness HRC 58-62, raceway contact fatigue life ≥1000 hours. Compatible models: Cat 950GC loader gearbox, 140M grader rear axle differential, 320D excavator swing mechanism, C15 engine fan clutch, D6T bulldozer final drive. Compatible bearing model: 7S-8671 (inner ring/taper), used for outer ring positioning of tapered roller bearings, bearing radial and bidirectional axial loads.

Assembly fit: Compatible with 180 mm diameter bearing housing bore (tolerance H7, +0.040/0 mm). 7S-8671 Inner ring (tapered) is used in pairs. During installation, heat-fit (80-100℃, 10 minutes) into the bearing housing bore, or cold-fit (-20 to -30℃, 30 minutes) into the bearing housing bore, ensuring the raceway fits snugly against the bearing housing bore without gaps.

Installation and Maintenance Points:
Before installation, clean the bearing housing bore and raceway. Inspect the raceway for cracks, rust, and scratches; surface roughness Ra≤0.08 μm; coaxiality error between the raceway and bearing housing bore≤0.02 mm.

Heat-fit raceway to bearing housing bore: Immerse the raceway in an 80-100℃ constant temperature oil bath for 10 minutes, then quickly insert it into the housing bore, using the end face locating ring for positioning.

Cold-fit raceway to bearing housing bore: Cool the raceway in an environment of -20 to -30℃ for 30 minutes, then insert it into the housing bore, ensuring the raceway end face fits snugly against the housing bore step. Do not strike the raceway end face.

Maintenance recommendations: Check the wear and fit of the raceway of the seat ring every 1500 hours. If the wear of the raceway exceeds 0.1 mm, or if peeling or cracks appear, replace it immediately. When replacing, it must be replaced at the same time as the inner ring (7S-8671) to avoid damage caused by uneven load.