CAT 188-4103 BEARING AS

CAT 188-4103 is a Caterpillar single-row tapered roller bearing assembly designed specifically for hydraulic pumps. It is compatible with the main pump/pilot pump of Cat 330C/345B excavators and other models. It is used to support the pump shaft and withstand radial and unidirectional axial loads, and is a key component to ensure the efficient and stable operation of the hydraulic system. The following is structured technical and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model 188-4103, Type: Single-row tapered roller bearing assembly, Material: Inner/Outer ring 52100 bearing steel, Rollers 20CrMnTi, Cage: Phenolic resin, Weight: Approx. 1.8 kg, Applicable Temperature: -30℃ to +110℃, Hardness: Inner/Outer ring HRC60-64, Rollers HRC58-62, Rated Speed: 4500 rpm (grease lubrication)

Key Dimensions
Inner Diameter: 50 mm (Tolerance 0 to -0.012 mm), Outer Diameter: 90 mm (Tolerance +0.012 to +0.025 mm), Width: 23 mm (Tolerance ±0.10 mm), Number of Rollers: 18, Roller Diameter: 10 mm, Roller Length: 18 mm, Taper Angle: 10°, Clearance Adjustment Range 0.03-0.08 mm, chamfer 1 mm × 45°, surface roughness Ra≤0.8 μm
Compatible Models and Applications: Compatible with Cat 330C and 345B excavators, for the input/output shaft of the hydraulic main pump and pilot pump. Matching parts include locknuts, thrust washers, and seals. Rated radial load ≥65 kN, rated axial load ≥42 kN, fatigue life ≥12000 hours
Performance Parameters: Lubrication method: Grease lubrication (Cat Moly Paste recommended), grease filler 15-20 g, limiting speed 6000 rpm (oil lubrication), coefficient of friction ≤0.0025, corrosion resistance meets ISO 9227 neutral salt spray test ≥48 hours without rust, radial runout after assembly ≤0.04 mm
Structural and Performance Advantages

Directional Load Bearing: The single-row tapered roller structure efficiently bears radial and unidirectional axial loads, adapting to the stress characteristics of hydraulic pump shaft systems, effectively dispersing stress, and reducing the risk of localized wear.

High-Precision Fit: 52100 bearing steel is hardened for high dimensional accuracy. The tapered angle design ensures a tight fit between the roller and raceway, minimizing radial runout during operation and improving pump shaft rotation accuracy and hydraulic system pressure stability.

Long-lasting Durability: The phenolic resin cage is lightweight and high-temperature resistant. The rollers are made of 20CrMnTi material, offering excellent impact resistance and wear resistance, suitable for the high-pressure, high-frequency operating conditions of engineering machinery hydraulic systems, extending service life.

Easy Maintenance: High component integration allows for integral press-fitting during installation. Clearance can be adjusted via locknuts, eliminating the need for complex tooling and reducing maintenance difficulty and time costs.

Installation and Maintenance Points:
**Before installation, clean the bearing assembly, pump shaft, and bearing housing, checking for burrs and cracks.** Use cold press fitting (pressure ≤15 kN, applied to the inner ring end face), and do not strike the outer ring. After installation, adjust the clearance to 0.03-0.08 mm, ensuring smooth rotation and end face runout ≤0.04 mm.

Run for 30 minutes, ensuring the bearing temperature is ≤75℃ and there are no abnormal noises or vibrations. Check the lubrication status and clearance every 1000 hours, and replenish grease every 2000 hours. Replace the assembly when roller wear exceeds 0.15 mm or pitting appears on the raceway.

When replacing parts, prioritize original parts, ensuring the cone angle, roller dimensions, and clearance meet standards. After installation, check the locknut and seal condition to prevent loosening or leakage that could lead to bearing failure.