| 摘要 |
PURPOSE:To maintain the proper size of the prescribed face width and stably hold a magnetic fluid, regardless of the dispersion of a shaft along an axial direction. CONSTITUTION:A groove type recess 24 is formed around the outer surface of a spindle 2 forming a shaft 1 at the side of a sleeve 5 in the vicinity of a seal section 21 sealing a magnetic fluid 15 in a gap 14a between the internal surface of a pole piece 11a and the external surface of the spindle 2. A gap between the top of the recess 24 and the lower end of a slope 25 shows face width 23, and even when an axial polishing or assembly error occurs in the spindle 2, a magnet or the like, the size of the face width 23 is constant. In other words, even when the spindle 2 of the shaft 1 is assembled in such a condition as dispersed along an axial direction, the size of the face width 23 of the spindle 2 of the section 21 sealing the fluid 15 is always constant, due to the existence of the recess 24. According to this construction, flux density in the section 21 becomes constant and the fluid 15 can be stably held. |
