Just ahead of the 2019 North American Vehicle Show set to begin in Atlanta next week, Eaton’s eMobility division has announced the launch of an all-new four-speed transmission. The new transmission is designed for Class 7 and 8 commercial vehicles and meet the growing demand in a number of segments, including pickup and delivery and port drayage in North America, China and Europe. Eaton said the new transmission is currently is currently undergoing evaluation trials with major truck
Eaton said the new transmission is the latest addition to company’s growing eMobility portfolio of electrified vehicle (EV) transmissions and other componentry, which also includes medium-duty 2- and 4-speed models that are also currently in production with several OEMs.
“Electric buses and trucks need to be able to go up hills and run at highway speeds when they are fully loaded,” said Scott Adams, senior vice president, eMobility, Eaton. “Our solution is to expand the range of the motor by adding an EV transmission. With this addition, the vehicle can perform well on hills and efficiently at highway speeds with a smaller, less costly motor.”
Eaton said its engineers designed the new heavy-duty 4-speed EV transmission to solve the primary issue related to single-speed drives: contradictory requirements for high efficiency at top speeds and increased torque at launch and low speeds. Fine-pitch helical gears ensure a smooth, low-noise operation, while the Eaton Transmission Control Unit’s shifting strategy is designed for fast gear changes and maximum efficiency, which extend range and battery life.
According to the company, the transmission is based on traditional, robust and efficient lay shaft architecture typical of AMTs but is designed specifically for electric commercial vehicle applications. Unlike traditional commercial vehicle transmissions, Eaton’s 4-speed EV gearbox does not have a clutch, and shifts are synchronized using the traction motor. It also operates at higher speeds than its traditional internal combustion gearbox counterparts, and gears are optimized for typical electric motor performance and power curves for maximum efficiency.
By providing higher output speed capability and torque range than a direct-drive system, Eaton said, the transmission enables the usage of a smaller, lighter electric motor for large commercial vehicles, which cuts down on the cost, a major buying point for commercial EV operators.