求翻译：滚动轴承的选择和代用 1）. 选择的方法和步骤 能否正确选用滚动轴承，对主机能否获得良好的工作性能，延长使用寿命；对企业能否缩短维修时间，减少维修费用，提高机器的运转率，都有着十分重要的作用。因此，不论是设计制造单位，还是维修使用单位， 在选择滚动轴承时都必须高度重视。 一般来说，选择轴承的步骤可能概括为： ①. 根据轴承工作条件（包括载荷方向及载荷类型、转速、润滑方式、同轴度要求、定位或非定位、安装和维修环境、环境温度等），选择轴承基本类型、公差等级和游隙； ②. 根据轴承的工作条件和受力情况和寿命要求，通过计算确定轴承型号，或根据使用要求，选定轴承型号，再验算寿命； ③. 验算所选轴承的额定载荷和极限转速。 选择轴承的主要考虑因素是极限转速、要求的确良寿命和载荷能力，其它的因素则有助于确定轴承类型、结构、尺寸及公差等级和游隙工求的最终方案。是什么意思？

Selection and maintenance of rolling bearing 1). Select the method and steps of correctly selection of rolling bearing, can host for good work performance, extended life; companies can shorten the repair time, reduce maintenance costs, increase the rate of operation of the machine, have a very important role. Therefore, both design and manufacturing units or the maintenance and use, in choosing a bearing must attach great importance to. Generally, select bearing of steps may General for: ①. under bearing work conditions (including load direction and the load type, and speed, and lubrication way, and with axis of requirements, and positioning or non-positioning, and installation and maintenance environment, and environment temperature,), select bearing basic type, and tolerance grade and tour gap; ②. under bearing of work conditions and by force situation and life requirements, through calculation determine bearing model, or under using requirements, selected bearing model, then checking life; ③. checking by selected bearing of rated load and limit speed. Selection of bearing the main consideration is the speed limit, and load capacity requirements Dacron life, other factors help to determine the bearing type, structure, size and grade of tolerance and clearance workers seeking the final plan.