Patent ID: 7787650

Claim:
An electromagnetic exciter comprising: a magnetic circuit assembly comprising an outer yoke including a bottom wall and a cylindrical side wall extending from a peripheral portion of the bottom wall upward with an axis centered, the cylindrical side wall of the outer yoke having an upper end that is opposite to the peripheral portion of the bottom wall, the magnetic circuit assembly further comprising a magnet and an inner yoke that are successively stacked on the bottom wall of the outer yoke coaxially with the axis of the outer yoke, wherein a magnetic gap is formed between the inner yoke and the cylindrical side wall of the outer yoke; a voice coil inserted into the magnetic gap; a casing accommodating the magnetic circuit assembly and the voice coil that is inserted in the magnetic gap, the casing comprising a cylindrical wall disposed around the cylindrical side wall of the outer yoke; a suspension secured on the upper end of the cylindrical side wall of the outer yoke and on the cylindrical wall of the casing to supportingly connect the magnetic circuit assembly to the casing; and a weight secured to an outer side surface of the cylindrical side wall of the outer yoke; wherein the suspension comprises a radially inner section, a radially outer section, and a connecting section interconnecting the radially inner section and the radially outer section: the radially inner section secured to the upper end of the cylindrical side wall of the outer yoke; the radially outer section secured to the cylindrical wall of the casing; and wherein the radially outer section of the suspension is secured to the cylindrical wall of the casing at a higher position than the radially inner section that is secured on the upper end of the cylindrical side wall of the outer yoke with the connecting section slopingly connecting the radially inner section and the radially outer section.