CAT 4J-3047 15.875mm Inner Diameter Needle Bearing

CAT 4J-3047 is a needle roller bearing specifically designed for Caterpillar hydraulic systems. It is commonly used in hydraulic pumps and steering mechanisms of wheeled tractors (models 621, 623, 627, etc.) to reduce axial friction and withstand certain axial loads. It is suitable for the compact installation space of hydraulic systems in construction machinery and ensures efficient operation of components. The following is structured technical and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model: 4J-3047, Type: Needle Roller Bearing (with Cage), Material: Bearing Steel (Needle Rollers) + Phenolic Resin (Cage), Single Weight: Approx. 0.02 kg, Operating Temperature: -40℃ to +120℃, Design Life: ≥8000 hours (normal operating conditions), Lubrication Method: Grease Lubrication, Suitable Hydraulic System Pressure: ≤35 MPa

Key Dimensions
Inner Diameter: 30 mm (Tolerance 0/+0.02 mm), Outer Diameter: 47 mm (Tolerance 0/-0.015 mm), Width: 2 mm (Tolerance ±0.05 mm), Needle Roller Diameter: 2 mm, Number of Needles: 18, Cage Thickness: 1.5 mm, Shaft Fit Clearance: 0.01-0.02 mm, Radial Runout: ≤0.03 mm

Compatible Models and Replacement Parts
Compatible with Cat Wheel Tractors Models 621, 623, 627, 627B, 639D, and 657E are suitable for hydraulic pumps, steering gears, and other hydraulic components.

Performance Parameters: Rated dynamic axial load 16.4 kN, rated static axial load 70 kN, coefficient of friction ≤0.003 (good lubrication conditions), limiting speed 3000 rpm (grease lubrication), impact strength ≥30 J/cm², cage breaking strength ≥1.5 kN.

Structural and Performance Advantages: Needle roller bearings have a compact structure, capable of withstanding large axial loads in a small installation space. They are suitable for the compact layout of hydraulic systems, reducing component space occupation and improving space utilization.

The bearing steel needle rollers have high hardness (HRC60-64) and good wear resistance. The phenolic resin cage has good lubricity and corrosion resistance, effectively extending bearing service life and making them suitable for harsh working conditions in engineering machinery.

The cage design prevents needle rollers from rubbing against each other, reducing operating noise while ensuring uniform needle roller distribution, improving bearing load capacity and operational stability, reducing component wear, and lowering maintenance costs. Installation and Maintenance Points: Before installation, clean the bearing and mounting surface to remove oil and impurities. Check for bearing damage and detached needle rollers. Use a special tool to press the bearing into its mounting position, avoiding impact that could deform the cage or damage the needle rollers.

After installation, apply an appropriate amount of lithium-based grease to ensure adequate lubrication of the needle rollers. During the initial operation (first 50 hours), regularly check the bearing’s running condition. If abnormal noises or temperature rises occur, troubleshoot promptly to prevent bearing damage.

Maintenance: Check the grease condition every 1500 hours. If the grease is found to be deteriorated, the bearing wear exceeds 0.05 mm, or the cage is damaged, replace it immediately. When replacing, use bearings of the same model; do not mix with needle roller bearings of different specifications to ensure component compatibility.