More Flexibility for Vehicle Concepts ZF Develops New 3-in-1 Electric Drive System

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High Revolution Drive is the name of ZF's latest innovation. The new drive concept builds on the existing Select platform and stands out primarily for its reduced weight and smaller footprint.

The new drive system has a motor speed of up to 30,000 rpm. This enables a smaller and lighter electric motor with reduced magnet requirements. A high-ratio, two-stage transmission delivers the required torque to the wheel. The new drive concept builds on the existing SELECT platform, giving vehicle manufacturers additional flexibility for new vehicle and platform designs.

The drive’s motor speed is significantly higher than that of standard solutions—including those from our own company. This was achieved primarily because the company focuses on the system as a whole, rather than just individual components. “Our system expertise really comes into play with the High Revolution Drive. We don’t optimize individual components in isolation, but rather consistently coordinate the electric motor, power electronics, and transmission,” says Thomas Meiser, head of the E-Mobility Business Unit at ZF, summing up the most important prerequisite.

The principle: At the same power output, a higher rotational speed reduces the required motor torque. Because this is closely related to the rotor volume, the electric motor can be designed to be smaller and lighter. For motor speeds of up to 30,000 rpm, the supplier increases the gear ratio of the two-stage spur gear transmission to approximately 18:1. This ensures that the required torque remains available at the wheel. ZF integrates the electric motor, inverter, and transmission into a 3-in-1 system. The design now being introduced achieves 200 kW of peak power and 3,500 Nm of peak torque at the wheel.

Reduce Noise and Vibrations

Keeping noise and vibrations under control even at high rotational speeds played a key role in the development process. High rotational speeds place special demands on noise performance. ZF addresses these demands through the integrated design of the components: “Robustness and low noise and vibration levels were key development goals from the very beginning,” emphasizes Meiser. “To achieve this, we considered the electric motor, gearing, bearings, and tooth geometry as a unified system. For the design presented here, 30,000 rpm is the economic and technical sweet spot.”

Less Magnetic Material, Lighter Weight

Compared to the standard drive of the ZF eDrive Platform Select with the same performance specifications and 18,000 rpm, the High Revolution Drive requires nearly 25 percent less installation space and weighs 25 percent less. However, this does not come at the expense of efficiency, which remains on par with that of the comparable standard drive from the Select platform. The required magnet mass is reduced by 50 percent. This not only offers cost advantages but also helps minimize dependencies in the supply chain.

The lower weight also helps to increase the electric range. The focus is on the high-volume passenger car market, with power outputs ranging from about 150 to 200 kW. The architecture is scalable for different power levels as well as 400- and 800-volt systems.

The New Powertrain is Part of the Platform Strategy

This new approach is also in line with ZF’s platform strategy: The High Revolution Drive is designed as a variant of the modular Select family and utilizes existing technologies. This combines predictable product costs with a high degree of flexibility for various industrialization concepts.

According to the supplier, it is in talks with several automakers regarding its new powertrain. Mass production is scheduled to begin by 2030.