CAT 446-7243 BEARING

CAT 446-7243 is a Caterpillar genuine single-row deep groove ball bearing, specifically designed for rotary piston motor shafts, used in the rotary hydraulic systems of equipment such as excavators, to withstand radial and bidirectional light axial loads. The following are precise original factory specifications and application information, excluding replacement parts (Cat®…).

Core Technical Parameters

Item Details
Part Model: CAT 446-7243 (Deep Groove Ball Bearing for Rotary Piston Motor Shaft)
Product Type: Support bearing for hydraulic motor shafts in engineering machinery, suitable for rotary motor spindles, bearing radial loads and bidirectional light axial loads, suitable for medium pressure and vibration conditions.

Material: Rings/Rolling Elements: AISI 52100 bearing steel (hardness HRC 60–64), Cage: Reinforced nylon, surface anti-oxidation treatment

Key Dimensions: Inner diameter 35 mm (1.378 in), Outer diameter 72 mm (2.835 in), Width 17 mm (0.669 in), Chamfer 1 mm, Inner ring fit tolerance k5, Outer ring fit tolerance G6

Rated Load: Basic rated dynamic load 25.5 kN, basic rated static load 14.2 kN, ultimate radial load 51 kN

Speed ​​Parameters: Grease lubrication limiting speed 7500 rpm, oil lubrication limiting speed 9000 rpm rpm

Sealing and Lubrication: Double-sided dust cover seal, pre-filled with lithium-based grease (NLGI 2 grade), operating temperature -30℃ ~ +120℃

Single Weight: Approx. 0.26 kg (0.57 lbs)

Operating Parameters: Suitable pressure ≤ 28 MPa, compatible with mineral oil, synthetic hydraulic oil, and other media.

Structure and Core Features:

Double-Sealed Protection: Double-sided dust cover design effectively prevents impurities and moisture from entering the hydraulic oil, extending bearing life and adapting to harsh working conditions.

Lightweight and High Rigidity: Reinforced nylon cage reduces weight while maintaining structural strength, capable of withstanding impact loads during the start-up and shutdown of the rotary motor.

Precise Fit: Precision machining ensures a raceway surface roughness Ra ≤ 0.08 μm, with precise tolerances to ensure motor shaft rotation accuracy and reduce operating noise.

Compatible Models and Application Scenarios:

Compatible Equipment: 320D2/323 excavator rotary piston motor, small loader hydraulic rotary system, and hydraulic motors for some C-series engines.

Core Application: Installed on the spindle support of a rotary motor, providing radial positioning and rotational support, suitable for medium-speed, medium-pressure rotary operation, ensuring smooth motor shaft operation and preventing component damage caused by vibration.

Installation and Maintenance Points

Installation: Clean the journal and bearing housing bore, checking for bearing deformation, cracks, or damaged dust covers.

Cold Press-In: Inner ring with shaft interference fit (k5), outer ring with bearing housing clearance fit (G6). Press-in force should be applied to the end face of the mating rings; rolling elements must not be subjected to force.

Post-Installation Inspection: Radial runout ≤ 0.02 mm, axial runout ≤ 0.04 mm.

Maintenance: Check bearing operating condition every 2000 hours. Replace immediately if abnormal noise, abnormal temperature rise, or leakage occurs.

During equipment maintenance, check bearing clearance. Replace bearings if it exceeds tolerance (>0.04 mm) to prevent increased shaft vibration.

Avoid contact with corrosive media. Change hydraulic oil regularly to prevent grease deterioration.