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This paper reports on the design of a synchronizer brake based on permanent magnets, capable of braking with an active zero-slip load. Eddy-current brakes are widely used in automation and transportation applications; however, their use is limited by the rotor speed. For low-speed and high-torque applications, designs based on permanent magnets are better suited. Zero-slip braking torque is increased by the use of permanent magnets but, consequently, so is the cogging torque. At first, the synchronizer brake was designed with 16 surface magnets on the rotor. However, in order to reduce the permanent magnet mass, the rotor was re-designed with half the number of surface magnets. This novel design helped lower cogging torque and fabrication costs. Simulation of the design, using the 3D transient with motion solver in commercial finite element software, showed promising results.

With the aim of producing innovative clutch actuation mechanisms for automotive transmissions, we are investigating a design based on power screws. The design strives to improve clutch actuation technology and minimize energy consumption by maintaining clutch lock-up independent of an external energy source. The system consists of a lead screw shaft-and-nut assembly, a clutch apply-plate, a set of wet clutch disks and a brushless DC motor. The clutch actuation assembly is separated from the clutch-pack via thrust bearings, which allows the use of a motor, while reducing the inertial load imposed by the conventional clutch-pack. A prototype of the design was fabricated and installed on a testbed, to mimic the installation of the actuator to replace the hydraulic components. A standard 12-disk clutch-pack of an automatic transmission was used within the apparatus. The formulation of the mathematical model of the entire testbed is described in this paper.