CAT 241-3818 Retainer Collar

CAT 241-3818 is a rigid retaining ring (shaft retaining ring type) used by Caterpillar for axial positioning of bearings/shafts. It is compatible with the final drive, slewing bearing or gearbox of excavators and loaders. Its core function is to lock the inner ring of the bearing, gear or bushing to prevent axial movement. It is suitable for medium and high speed and medium and heavy load conditions, and has strong resistance to vibration and impact. It is a key component for positioning of the transmission system. The following is structured technical and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model 241-3818, Type: Rigid retaining ring for shaft (one-piece molded retaining ring structure), Material: 42CrMo alloy steel (quenched and tempered, hardness HRC 32-38), Surface: blackened oxide (corrosion resistance ≥72 hours salt spray test), Single weight: approximately 0.68 kg, Operating temperature: -40℃ to +180℃, Installation method: hot fitting + bolt-assisted positioning, Design life: ≥12000 hours (normal operating conditions)

Key Dimensions
Inner diameter: 88.9 mm (3.5 inches, tolerance 0/-0.02 mm), Outer diameter: 114.3 mm (4.5 inches, tolerance 0/+0.025 mm), Total thickness: 19.05 mm (0.75 inches, tolerance 0/-0.05 mm), Edge height: 5.08 mm, Number of bolt holes: 6 (evenly distributed, diameter…) 10.5 mm), bolt hole center circle diameter 101.6 mm, flange fillet radius R1.5 mm, inner hole surface roughness Ra≤0.8 μm, outer circle cylindricity≤0.015 mm
Compatible Models and Accessories: Compatible with Cat 320D2 and 336D2 excavators (final drive planetary carrier bearing positioning), 966M loader (gearbox output shaft bearing locking), 349D2 slewing bearing drive shaft bearing positioning, and compatible with 241-3819 washers, M10×30 socket head cap screws, 366-9274 retaining rings, and 5V-5498 retainers.
Performance Parameters: Axial rated load ≥50 kN, radial positioning accuracy ≤0.02 mm, impact load ≥18 kN, bolt tightening torque 65 N・m, heat fitting temperature 80-100℃ (interference 0.03-0.05 mm), fatigue life ≥8000 (Load Cycles)

Structural and Performance Advantages

Made of 42CrMo alloy steel, the heat-treated ring combines strength and toughness. The one-piece molded retaining ring structure has no splicing gaps, ensuring high positioning accuracy. Suitable for high-speed, high-load conditions in transmission systems, it prevents positioning failure caused by ring deformation.

The evenly distributed design of the retaining edge and bolt holes ensures uniform stress distribution, effectively absorbing transmission system vibration, reducing impact between components, protecting core components such as bearings and gears, and improving the overall reliability of the transmission system.

The anodized black surface treatment is suitable for harsh outdoor conditions, reducing the risk of corrosion. The heat-fit installation method ensures an interference fit between the retaining ring and the shaft, and bolt-assisted positioning prevents loosening, making it suitable for frequent start-stop operations.

Installation and Maintenance Points:
**Before installation, clean the shaft diameter, bearing inner hole, and bearing end face, checking for burrs and rust. Measure the shaft diameter (88.9 mm) and bearing inner hole, ensuring an interference fit of 0.03-0.05 mm.** Heat the bearing ring to 80-100℃ and quickly insert it into the shaft’s positioning position. Allow it to cool and naturally fit together.

Install the matching washers and M10×30 socket head cap screws, tightening them diagonally and evenly to a torque of 65 N·m. After installation, check the fit between the bearing ring flange and the bearing inner ring; ensure there are no gaps or looseness, and that the rotating shaft system rotates smoothly without jamming.

Maintenance: Check the bolt torque and bearing ring condition every 2500 hours. If the bearing ring is deformed, cracked, or the bolts are loose, replace it immediately. When replacing, replace the entire bearing ring and matching washers to avoid reusing old parts, which could reduce positioning accuracy.