| 摘要 |
A cap (2) is made of sintered hard metal and has on the inside a cylindrical surface (20) and a frusto-conical surface (21) that are true ground. The cap's cylindrical surface (20) is fitted with radial play around an outer cylindrical surface (9) of an underlying middle (1) and the cap's frusto-conical surface (21) has the same inclination as a subjacent frusto-conical surface (14) on the outside of the middle. The cap (2) and the middle (1) are secured to one another by a ring of deformable material sandwiched between their cylindrical surfaces (9, 20). On the outside the cap (2) is formed over its thicker main portion (18) with a trued and polished surface (22) having the same inclination as its inside frusto-conical surface (21) such as to provide the thicker portion (18) with a parallelogrammatic cross-section.
|
