CAT 3G-7698 TRUNNION

The CAT 3G-7698 is a Caterpillar original steering/articulation trunnion, used in the steering and articulation parts of engineering machinery. It plays a crucial role in articulating support, transmitting loads, and enabling flexible rotation. It is compatible with a variety of heavy-duty equipment. The following are its key features.

Core Technical Parameters

Item Details
Part Model: CAT 3G-7698 (Steering/Hinge Trunnion, Single Piece)

Material: 4140 alloy steel, heat-treated with temper, tensile strength ≥1000MPa, hardness HRC 30-35, combining high strength and toughness, wear-resistant and impact-resistant

Key Dimensions: Spherical diameter approx. 127mm (5 inches), total length approx. 254mm (10 inches), mounting hole diameter approx. 50.8mm (2 inches), compatible with standard hinge bushings and bearings

Single Weight: Approx. 9.1kg (20 lbs)

Core Features: High-precision spherical machining, compatible with self-lubricating bushings, low rotational resistance; wear-resistant surface after heat treatment, suitable for frequent steering and hinge movements under high load conditions

Suitable Operating Conditions: Operating temperature -40℃ to + 120℃, suitable for steering articulation systems of loaders, graders, tracked bulldozers, etc., resistant to impact loads and alternating stress.

Structure and Core Functions

Integrated Spherical Structure: The spherical surface mates with the hinge hole, paired with a self-lubricating bushing, achieving low-friction rotation and ensuring flexible steering/articulation movements while transmitting longitudinal and lateral loads during equipment travel and operation.

High-Strength Material and Heat Treatment: 4140 alloy steel is heat-treated to form a wear-resistant layer on the surface while maintaining internal toughness, preventing the trunnion from breaking or deforming under impact loads and extending its service life.

Positioning and Installation Structure: Mounting flanges and locating pin holes at both ends ensure precise positioning of the trunnion and the frame/articulation frame, preventing misalignment after installation and ensuring steering/articulation geometric accuracy.

Load Transfer and Buffering: As a core load-bearing component of the articulation part, it evenly transmits loads, reduces local stress concentration, and, together with the bushing, absorbs vibrations, improving the stability of equipment travel and operation.

Compatible Models and Application Scenarios

Compatible Equipment: CAT 966G/H/K loaders, 140H/G graders, D6R/D7R tracked bulldozers, and other heavy-duty construction machinery using articulated steering (Cat®…).

Installation Locations: Primarily used at the articulation points between the chassis and front/rear axles, the articulation points between the pusharm and chassis, and the connection points between the steering cylinder and chassis.

Core Purpose: Enables equipment steering and articulation movements, supports equipment weight and transmits operational loads, adapts to frequent steering and heavy-load operation conditions, and ensures equipment maneuverability and structural reliability.

Installation and Maintenance Points

Installation: Clean the trunnion mounting surface and articulation holes, and check the trunnion spherical surface for scratches, cracks, or other damage; during installation, ensure the locating pin is embedded in the locating hole, the flange surface is tightly fitted, and the bolts are tightened symmetrically to the original torque, typically 220-250 N·m.

When using the original self-lubricating bushing, the gap between the bushing and the trunnion spherical surface should be controlled between 0.05-0.10mm to avoid excessive gaps that could lead to abnormal noise or accelerated wear.

Maintenance: Regularly check the wear of the trunnion and bushing. When the spherical wear exceeds 0.5mm or the bushing fails, replace the trunnion and bushing promptly to prevent loosening or misalignment of the hinge.

Before operating the equipment, check the tightness of the trunnion fixing bolts to prevent loose bolts from causing trunnion displacement and structural damage.

Avoid high-speed operation or overloading of the equipment on rough surfaces to reduce impact loads on the trunnion and prevent premature damage.