| 摘要 |
A group of magnetic poles (74, 78) is formed on each end of a columnar yoke (72). The magnetic pole groups each include four magnetic poles (74a, 74b, 74c, 74d, 78a, 78b, 78c, 78d) which protrude from the center of the yoke at right angles to one another and to the longitudinal direction of the yoke. A cylindrical supported body (54) surrounds the yoke and the magnetic poles. A ring-shaped member (68) formed of a ferromagnetic material is fixed to the inner peripheral surface of the supported body so that both end portions of the ring-shaped member are in alignment with the centers of their corresponding magnetic poles of the magnetic pole groups. Coils (76a, 76b, 76c, 76d, 80a, 80b, 80c, 80d) are wound around the individual magnetic poles of the magnetic pole groups, whereby loops are formed along which magnetic fluxes delivered from each aligned pair of magnetic poles enter the ring-shaped member substantially at right angles to the peripheral surface thereof, and return to those original magnetic poles via another pair of magnetic poles adjacent thereto. Thus, the supported body is supported in its radial direction. A coil (82) is wound around the yoke, whereby loops are formed along which magnetic fluxes pass through the yoke along its longitudinal direction, enter one end face of the ring-shaped member at right angles thereto via the magnetic poles of the first magnetic pole group, pass through the ring-shaped member along its longitudinal direction, and enter the magnetic poles of the second magnetic pole group via the other end face of the ring-shaped member. Thus, the supported body is supported in its longitudinal direction. |
