This invention relates to a monophase electromagnetic rotary actuator of angular travel between 70/N and 110/N degrees exhibiting a high torque/mass ratio and a torque that is approximately independent of the angular position of the rotor. A relation between the magnetized width Y.sub.a measured on the mean diameter of the magnets, the width of the angular arc C through which the rotor passes on the mean diameter of the magnets, the width S measured on the mean diameter of the magnets between two adjacent stator poles, the radial length of the magnets L, and the constant length E of the air gap is: where E' is between E/2 and E. Furthermore, C+2 E'/E >6 and L/E>0.75.
An electromagnetic drive device includes a coil frame with a hollow tubular shape, a magnet rotor rotatably disposed in the coil frame through a rotational shaft, a transmission member for transmitting a rotation of the magnet rotor, and a coil wound around an outer periphery of the coil frame. The coil frame is formed of two coil frame halves divided vertically along the rotational shaft of the rotor, and the coil is wound in a direction crossing connection faces (joint faces) of the two coil frame halves on upper and lower end surfaces thereof.
A a rotating electromagnetic actuator with limited stroke, including at least 2N poles on the stator, N being a whole number, energized by at least one energizer coil and N magnetized parts on the rotor arranged in an air gap of thickness E wherein each magnetized part is juxtaposed with at least one ferromagnetic part with a thickness e between 0 and E, defining one or two air gaps with a total length of E-e.
An actuator for rotating (or moving) a rotor (or a moving member) according to the current flowing through an electromagnetic coil. Magnetic energy of magnetomotive force induced in the electromagnetic coil when energized is stored in an air gap and a sub-air gap provided in a magnetic path. The rotor (or the moving member) comes to rest at a position where the stored magnetic energy becomes the smallest. The stored magnetic energy serves as a source of counterforce and functions in the same way as a spring.
Electromagnetic actuator comprising a stationary stator (I) with a central pole (3) of length X.sub.c and two lateral poles (4,5) of length X.sub.L, said stator including an exciting coil (6). The actuator further comprises a moving part (2) with thin permanent magnets (12,13,22,23) magnetized in the direction of the air gap. It is characterized in that the moving member (2) consists of at least two independent elements (10,20) each movable in the parallel directions to the intersection of the air gap plane and the stationary stator median plane (1), in opposite directions. Each of the moving parts (10,29) has a pair of thin magnets (12,13,22,23) magnetized in alternate directions, integral with a yoke (11,21) of soft material. The thin magnets (22,23) of one of the moving elements (20) are magnetized in the opposite direction to the corresponding thin magnets (12,13) of the adjacent moving element (10), the yokes (11,21) defining with the stationary stator part the air gap (E).
A rocking motor comprises a coil wound around a hollow coil bobbin. A rotor is rotatably mounted at a position close to an end portion of the coil bobbin. The rotor has a center shaft and a permanent magnet and is magnetized with two poles such that the positions of the poles are located close to the coil and the magnetization angle is greater than 90 degrees but less than 180 degrees. The positions of the poles of the rotor and the coil are adjacent to one another so that a rotary torque can be efficiently obtained by a magnetic force generated by the coil. The rocking motor can generate a high power output with a relatively low power supply and its operational performance is not adversely affected by an external magnetic field.
