Transmission Solenoids in Electric Vehicles

Thomas picked by leading OEM

Electric vehicles can also manage without multi-speed transmission. This is because, unlike combustion engines, electric motors deliver a high torque in a broad range of rotational speeds. However, the manufacturer that has now picked Thomas for its new series is going down a different route, choosing a two-speed gearbox in which Thomas’s transmission solenoids are intended to ensure precise switching. The OEM is adding the extra gear for the sake of increased efficiency, which could pay off in the form of a greater range, better acceleration, or a smaller motor – thus saving on resources.

Solenoids for transmission applications

High-precision control of volume flows and pressures

Low wear due to optimized design

Tried-and-tested over many years

The order win is no accident: Many carmakers rely on transmission solenoids from Thomas, not least because they promise switching behavior that meets the toughest requirements. This is also the case in the OEM’s current automatic transmissions: Proportional solenoids from Thomas have been used in a wide range of series and models since 2019.
Needless to say, the desired product characteristics were naturally particularly high: The manufacturer required the product to have a high power density, an excellent performance level and low hysteresis – all in a commercially competitive overall package. In the development project, Thomas managed to bring all of these requirements together better than the competition, which included some highly reputable Tier 1 suppliers.

The market benchmark

The hysteresis value indicates how precisely a desired action is being carried out. The figure factors in the system’s previous history and its current state, because these factors exert a constantly changing influence on mechanical and magnetic behavior. In a nutshell, the smaller the hysteresis is, the less power is lost and the more efficiency savings can be made.

“Optimizing the hysteresis values was particularly important to the OEM during the development work at the time,” explains Heiner Held, Key Account Manager at Thomas. “Working together with the customer, we succeeded in developing a product that sets the market benchmark in this respect.”

A pioneering project

This project is a particularly important one for Thomas, not least because the market volume is huge: Over 50 million pieces will have been manufactured by the end of the production period, and the number of items requested as part of delivery scheduling could well more than double to over 10 million this year alone. Much of the value creation happens in-house, from injection molding, winding the coils, and precision machining through to laser welding, final assembly, and end-of-line testing. What is more, because Thomas uses carry-over parts wherever possible, its proportional solenoid can be adapted to fit new vehicle technologies with relatively little effort – and this includes the requirements of an electric vehicle, as its order win demonstrates.