High Performance Surface Treatments for Electric & Hybrid Vehicle E-Axle’s.

Posted on Jun 10, 2024

Traditionally combustion engine cars have used a differential to split the engine torque in two directions at different speeds. Power from the engine runs through a transmission and turns the vehicles axle in one direction. However, with the introduction of Electric & Hybrid Cars there is now another choice that no longer needs a differential.

The E-Axle is a compact, electric drive solution for battery-electric vehicles and hybrid applications. The electric motor, power electronics and transmission are combined in a compact unit directly powering the vehicle’s axle. Through regenerative braking the load is applied in both directions to recharge the battery.

Therefore, the need for fatigue, seizure and wear resistant surface treatment is of paramount importance. Especially when being loaded in both directions and under high torque with a low RPM.

ARCOR® fulfils all these requirements and outperforms other case hardening, gas nitriding & coatings options in this application.

The need for differential systems remains, and the HEF Group are privileged to globally apply CLIN™ (controlled liquid ionic nitrocarburizing) treatments many of these parts.

1) Differential case (body & cap)

ARCOR® mitigates the contact wear between spinning elements, and provides:

• High resistance to wear and fatigue
• Smaller of parts design can be reached (thanks to increased part resistance).
• Cost saving (potential to eliminate washers)
• Minimal distortion
• Corrosion improvement (moderated)

2) Differential shaft

ARCOR® reduces the friction between the shaft, gear and case to help prevent seizure.
It offers an environmental & performance advantage over electroless nickel plating:

• Lubrication and friction coefficient improvement;
• Superior in E-Axle technology when being loaded in both directions and under high torque, low RPM situations;
• High resistance to wear, fatigue and seizure;
• No flaking or delamination issues as ARCOR® is a diffusion process unlike plating.

3) Differential pin

ARCOR® provides a durable contact surfaces that do not score exposed to heavy loading. It brings the opportunity to:

• Reduce the number of operations;
• Lubrication and friction coefficient improvement;
• Nickel plating replacement;01
• Superior in E-Axle technology when being loaded in both directions and under high torque, low RPM situations;
• High resistance to wear, fatigue and seizure;
• No flaking or delamination issues as it is a diffusion process unlike plating.

4) Differential washer and spacer

ARCOR® has superior wear resistance and corrosion resistance than the traditional treatment (gas nitriding + phosphating process). Improvement allowed:

• Better wear resistance;
• Better corrosion resistance;
• More optimized manufacturing process and lower cost.

The ARCOR® process forms a uniform compound layer thickness due to its high temperature uniformity, thermal transfer method & optimal nitriding potential. This also yields a fast process time, enabling our customer to enjoy quick turn-a-round times.

Benefiting from the HEF Group’s complete vertical integration and 70 years’ experience in liquid nitriding, ARCOR® processes are robust, repeatable solutions.