Press Release
ZF High Revolution Drive: Higher Speeds, Less Space
- Up to 30,000 rpm with low noise, backed by decades of transmission expertise
- Compact design makes it easier for vehicle manufacturers to integrate the drive into new vehicle architectures
- Scalable architecture makes the drive suitable for different power ratings and both 400- and 800-volt platforms
Friedrichshafen. ZF has developed the High Revolution Drive, a compact 3-in-1 electric drive that spins at up to 30,000 rpm, so it's smaller and lighter than conventional drives while delivering the same power. This enables a smaller, lighter electric motor with reduced magnet requirements. A high-ratio two-stage transmission delivers the required torque at the wheel. The new drive concept builds on the existing SELECT platform, so automakers can bring it into new vehicles faster and at lower development cost.
The motor speed of the High Revolution Drive is significantly higher than that of conventional systems. Making that work requires the whole system to work together: “The High Revolution Drive draws on ZF’s full systems expertise,” says Thomas Meiser, Head of the E-Mobility Business Unit at ZF. “Rather than optimizing individual components in isolation, we systematically coordinate the electric motor, power electronics and transmission.”
The principle is simple: At the same power output, a higher rotational speed reduces the required motor torque. Since torque is closely linked to rotor volume, the electric motor can be designed to be smaller and lighter. To turn that high speed into usable torque, a two-stage spur gear transmission with a ratio of about 18:1 makes sure the required torque reaches the wheels. The version shown delivers peak output of 200 kW and peak wheel torque of 3,500 Nm.
High Speed, Low Noise
Higher speeds make noise and vibration harder to control. ZF tackles this with decades of gear and transmission experience. ZF addresses these challenges through the coordinated design of the components: “Robustness and low noise and vibration levels were stringent development targets from the outset,” says Meiser. “To achieve this, we considered the electric motor, gearing, bearings and tooth geometry as an integrated system. For the configuration presented, 30,000 rpm is the economic and technical sweet spot.”
Reduced Magnet Mass, Weight and Installation Space
The High Revolution Drive is nearly 25 percent smaller and nearly 25 percent lighter than a comparable SELECT drive running at 18,000 rpm. The required magnet mass is reduced by 50 percent, which lowers costs and reduces dependence on critical supply chains. Even at high rotational speeds and with a high gear ratio, the system achieves an efficiency of nearly 93 percent, on par with the comparable SELECT system.
The lower weight also helps increase electric range. The focus is on the high-volume passenger car market, with drive outputs of approximately 150 to 200 kW. The architecture is scalable for different power ratings and for both 400- and 800-volt systems.
SELECT: New Drive Concept on a Proven Platform
The approach also follows ZF’s platform strategy: The High Revolution Drive is designed as a variant of the modular SELECT platform and uses existing technologies. This keeps product costs predictable while giving automakers flexibility in how the drive is produced. “With SELECT, we do not have to start from scratch for every new drive variant,” says Meiser. “We use our modular system to tailor new concepts to different customer requirements.”
ZF is already in talks with several automakers and is targeting production by 2030.
