Linear Actuators for High-Speed Reciprocating Motion with Dual Halbach Arrays (Fundamental Consideration of the Effect of Magnet Arrangement on Thrust Characteristics)

To achieve higher performance in spark-ignition engines, the intake and exhaust valves must be controlled in a stepless manner according to the engine speed. Our research group has been continuously studying the electromagnetic drive valve system using a linear actuator. We designed a linear actuator with a dual Halbach array of permanent magnets in the stator to increase the thrust of the linear actuator. The thrust characteristics of the proposed model were investigated using electromagnetic field analysis based on the finite element method. The analysis confirmed that the Halbach array concentrates the magnetic flux on the coil side, which generates Lorentz force. From the analysis results, the proposed liner actuator can generate thrust for driving the engine valve, and optimal permanent magnets in stator can be obtained to generate higher thrust.