滚动体（球/滚子）

滚动体是滚动轴承中的关键部件，通过滚动接触传递载荷并减少摩擦。它们主要有两种形式：球（球形）用于承受径向和轴向载荷，接触方式为点接触；滚子（圆柱、圆锥、球面或滚针）用于承受更高载荷，接触方式为线接触。这些元件保持轴承滚道之间的分离，均匀分布载荷，并实现机械系统中的精确旋转运动。

滚动体基于滚动摩擦原理工作，其摩擦远低于滑动摩擦。当轴承旋转时，滚动体在内圈和外圈之间滚动，将滑动运动转化为滚动运动，从而减少能量损失、发热和磨损。几何形状（球或滚子）决定接触模式：球的点接触将应力分布在小面积上，而滚子的线接触通过沿一条线分散应力来承受更重的载荷。

Rolling elements operate on the principle of rolling friction, which is significantly lower than sliding friction. As the bearing rotates, these elements roll between the inner and outer races, converting sliding motion into rolling motion. This reduces energy loss, heat generation, and wear. The geometry (ball or roller) determines the contact pattern: point contact for balls distributes stress over a small area, while line contact for rollers handles heavier loads by spreading stress along a line.