Specialty Lubricants for Steering Components

For plastic-to-metal interfaces, a medium-viscosity, synthetic hydrocarbon grease enhanced by PTFE ensures good slip and low “stiction.” For metal-to-metal interfaces, a heavier synthetic hydrocarbon grease is recommended. A lighter grease designed for sliding surfaces is recommended for tight tolerances between telescoping shafts.

Rack and pinion designs often feature high loads and tight tolerances. Lubricants formulated with Extreme Pressure additives withstand high loads to reduce friction to prevent wear. A lubricant with good adhesion and low temperature performance is recommended to ensure reliable operation. Plastic and steel compatibility should also be considered.

If not properly lubricated, couplings, and ball bearings located at the end of the steering column, can transfer noise and vibration through the steering column up to the driver. Greases can quiet these applications and provide durability and wear protection. Load should be considered when selecting a grease. Heavily loaded designs require a heavy viscosity grease to ensure the proper wear prevention and mechanical damping properties.

Light weight synthetic hydrocarbon greases with advanced additive packages greatly reduce frictional torque between the gearing components. This allows for lower current draw over extended periods of use. They also improve low temperature torque performance, while providing wear protection and vibrational damping. Grease can also be used for its thermal management, corrosion protection, and wear mitigating capabilities. 

The friction from the junction of the yoke and steering rack can transmit vibrations that are felt by the driver. Yokes require a grease with excellent damping characteristics to minimize noise and vibration. Lubricants with good film strength are ideal tare ideal for these sliding conditions to reduce friction.

Bellows protect the steering rack and pinion and tie road end from external contamination and hence optimize gear performance. The grease helps seal these bellows which potentially operate at wide temperature ranges.

The input shaft connect is a universal joint which links the intermediate steering shaft with the rest of the steering system. This joint requires a mechanically stable, corrosion resistant and wide-temperature grease.

The ball nut helps overcome friction and wear in the steering gear through circulation of ball bearings between the worm and the nut itself. The grease helps overcome energy losses by further reduction in friction between the two metal surfaces and loading conditions.

Our magnetic brake system simulates an OEMs ‘run-in’ process. This is a high load, high speed, test entirely dedicated to removing high spots—or residual imperfections from the manufacturing process. When high spots are removed, it allows our engineers to understand how our lubricants will perform in an aged EPS system.

The EPS rig uses a feedback loop with two server motors that rotate from 0-540 degrees at 30 rotations per minute. Engineers can then use the feedback loop to simulate specific loads at different wheel rotations. OEMs are constantly trying to create systems that operate at higher loads. Our rig can simulate loads of up to 120 newton-meters to simulate the different EPS load requirements. Using the rigs infrared camera, our engineers can see the temperature distribution of the entire gear assembly. This allows us to assess how well our lubricants are reducing the amount of heat generated by the motor under specific loads and wheel rotations.

This rig is a non-loaded parking check, also known as a Backdrive check. This uses a high-resolution torque transducer to assess gear-to-torque distribution when a wheel is turned all the way in one direction. With this information, our engineers can remove the peaks and valleys of that distribution data to obtain the average gear-to-torque distribution for the system. This test allows us to understand frictional characteristics in EPS systems and how they affect the “feel” of steering.