| 摘要 |
<p>PURPOSE:To obtain a small device by forming a part adjacent to a permanent magnet in a taper type reaching the side surface of a main body part of each core constituting a center core, while setting a base point at a position retreated by a specified distance parallel to the axial direction from the outermost end of the end surface facing the permanent magnet. CONSTITUTION:In a core 11 or the like, an end portion 11b or the like of a part adjacent to a permanent magnet 17 or the like is formed in a taper type. When the taper part is formed as a gentle inclination part, the weight is reduced by that amount, and the winding part of a primary coil 21 is lengthened, so that performance can be improved. But when the core 11 or the like is formed to be, e.g. T-shaped, magnetic flux is concentrated, and magnetic resistance is increased, so that specified ignition characteristics can not obtained. Hence the core 11 or the like is formed in a taper type connecting the position reaching the main body part side surface of the core 11 or the like and the position retreated from the end surface facing the permanent magnet 17 or the like parallel with the axial direction by the minimum amount necessary for press processing, with an inclination angle of 40-50 deg. from the outermost part of the end surface facing the permanent magnet 11 or the like.</p> |
