专业英语第六课.doc

Lesson 6 Rolling Contact Bearings  The purpose of a bearing is to support a load while permitting relative motion between two elements of a machine. The term rolling contact bearings refers to the wide variety of bearings that use spherical ball or some other type of roller between the stationary and the moving element. The most common type of bearing supports a rotating shaft, resisting purely radial loads or a combination of radial and axial(thrust)loads. Some bearings are designed to carry only thrust loads. Most bearings are used in applications involving rotation, but some are used in linear motion applications. The components of a typical rolling contact bearing are the inner race, the outer race, and the rolling elements. Figure 1.8 shows the common single-row, deep_groove ball bearing. Usually the outer race is stationary and is held by the housing of the machine. The inner race is pressed onto the rotating shaft and thus rotates with it. Then the balls roll between the outer and inner races. The load path is from the shaft, to the inner race, to the balls, to the outer race, and finally to the housing. The presence of the balls allows a very smooth, low-friction rotation of the shaft. The typical coefficient of friction for a rolling contact bearing is approximately 0.001 to 0.005. These values reflect only the rolling elements themselves and the means of retaining them in the bearing. Types of Rolling Contact Bearing Here we discuss several different types of rolling contact bearings and the applications in which each is typically used. Radial loads act toward the center of the bearing along a radius. Such loads are 轴承的目的是承受载荷而允许机器的两个要 素之间的相对运动。滚动接触轴承是在静止元件和 运动元件之间使用球和其他类型滚动体的、种类繁 多的轴承。最常见的轴承支持转轴、抗纯径向负荷 或联合(逆)的径向和轴向负载。一些轴承被设计只 用于传递推力负载。大多数轴承被用于旋转运动的 应用,但也有一些被用于在直线运动的应用。 一个典型的滚动接触轴承的部件是内圈,外 圈,滚动元素。图1.8展示了普通的单列深沟球轴 承。 通常外圈是固定的并且受到机器外壳的容纳。 内圈压入到转轴上,和转轴一起旋转。然后滚球在 外圈和内圈之间。传递路径从轴、内圈、球,到外 圈,最后到外壳。球面上,允许一个很光滑,低摩擦 轴转动。典型的滚动接