CAT 171-8970 INSERT-COUPL

CAT 171-8970 is a Caterpillar construction machinery flexible coupling insert, also known as a rubber coupling block. It is primarily used in the connection between the engine and hydraulic pump, and the gearbox and drive shaft, transmitting torque and compensating for installation misalignment and working displacement between the two shafts. It is suitable for the power transmission systems of small and medium-sized excavators/loaders. The following is precise technical and application information:

Core Technical Parameters
Item Details
Part Model: CAT 171-8970 (1718970) Coupling Insert, compatible with coupling model 6Y-4771, 3 inserts per set (120° evenly distributed)

Core Material: Polyurethane (PU) + steel frame composite structure, PU hardness Shore A 92±3, tensile strength 45 MPa, elongation at break 300%, single weight approximately 0.52 kg (1.15 lb)

Key Dimensions: Outer diameter 101.6 mm, inner diameter 38.1 mm, thickness 19.05 mm, insert protrusion height 12.7 mm, steel frame diameter 38.1 mm (tolerance ±0.02 mm), center distance 63.5 mm

Rated load: Rated torque 850 N·m, maximum instantaneous torque 1200 N·m, suitable speed ≤3000 r/min, operating temperature -30℃ to +100℃

Suitable working conditions: Suitable for power transmission parts with torsional vibration, installation deviation ≤0.5 mm, angular displacement ≤1.5°, suitable for mineral oil-based working environment, oil-resistant and wear-resistant

Compatible models: CAT 305.5E2/306E2 excavators (engine – main pump coupling), 906M loader (gearbox – drive shaft connection), 226D3 skid steer loader (hydraulic pump – motor connection)

Accessories: Compatible coupling flange 486-7817, bolts 106-7772 (M12×35), anti-loosening nut 8T-4124, requires locating pin 148-8002 during installation. Core Functions and Structural Features:

Torque Transmission: Polyurethane elastomer transmits power, steel frame ensures the strength of the connection between the insert and flange, adapting to the torque output of the power system and preventing power interruption.

Misalignment Compensation: Compensates for radial, angular, and axial displacement of two shafts, absorbs installation errors and working deformation, reduces transmission impact, and lowers noise and vibration.

Vibration Damping: The elastic material absorbs torsional vibrations from the engine and hydraulic pump, protecting transmission components from impact loads and extending the life of couplings and shaft systems.

Wear-Resistant and Durable: Polyurethane material is oil-resistant and anti-aging, suitable for harsh working conditions in engineering machinery, with a service life of approximately 2000 working hours (under normal conditions).

Installation and Maintenance Points:
Installation Specifications: Clean the insert, coupling flange, and bolt holes, removing oil and burrs. Check the insert for cracks and deformation, and the steel frame for rust.

The inserts are evenly distributed at 120° intervals within the flange grooves, ensuring a complete fit between the protrusions and grooves. The bolt pre-tightening torque is 80 N·m, tightened symmetrically in 2-3 stages.

After installation, check that the coaxiality deviation between the two shafts is ≤0.2 mm and the angular displacement is ≤0.5°. During trial operation, there should be no abnormal vibration or noise.

Maintenance Recommendations: Check the wear and aging of the inserts every 1000 working hours. When cracks appear on the insert surface, wear exceeds 2 mm, or elasticity decreases, the entire set (3 pieces/set) must be replaced.

Avoid prolonged overload operation to prevent premature aging and breakage of the inserts, which could lead to power transmission interruption.