金属直线轴承是一种以低成本生产的直线运动系统，用于无限行程与圆柱轴配合使用。广泛应用于精密？机床、纺织机械、食品包装机械、印刷机械等工业机械的滑动部件。

　　Metal linear bearings are a low-cost linear motion system designed for use with infinite travel and cylindrical shafts. Widely used in precision? Sliding parts of industrial machinery such as machine tools, textile machinery, food packaging machinery, printing machinery, etc.

　　金属直线轴承是一种以低成本生产的直线运动系统，用于无限行程与圆柱轴配合使用。广泛应用于精密机床、纺织机械、食品包装机械、印刷机械等工业机械的滑动部件。直线导轨通常按照形式如下安装：

　　Metal linear bearings are a low-cost linear motion system designed for use with infinite travel and cylindrical shafts. Widely used as sliding components in industrial machinery such as precision machine tools, textile machinery, food packaging machinery, printing machinery, etc. Linear guides are usually installed in the following form:

　　1.一端固定——另一端支承?导轨一端固定，另一端支承。固定端同时承受轴向力和径向力；支承端只承受径向力，而且能作微量的轴向浮动，可以减少或避免因导轨自重而出现的弯曲，同时导轨热变形可以自由向一端伸长。这种结构使用广泛，目前国内中小型数控车床、立式加工中心等均采用这种结构。

　　1. One end fixed - the other end supports the rail with one end fixed and the other end supported. The fixed end simultaneously bears axial and radial forces; The supporting end only bears radial force and can undergo slight axial floating, which can reduce or avoid bending caused by the self weight of the guide rail. At the same time, the thermal deformation of the guide rail can be freely extended towards one end. This structure is the most widely used, currently used in small and medium-sized CNC lathes, vertical machining centers, and other applications in China.

　　2.一端固定——一端自由? ?导轨一端固定，另一端自由。固定端轴承同时承受轴向力和径向力，这种支承方式用于行程小的短导轨或者用于全闭环的机床，因为这种结构的机械定位精度是不可靠的，特别是对于长径比大的导轨（直线导轨相对细长），热变性是很明显的，1.5m长的导轨在冷、热的不同环境下变化0.05~0.10mm是很正常的。但是由于他的结构简单，安装调试方便，许多高精度机床仍然采用这种结构，但是必须加装光栅，采用全闭环反馈。

　　2. Fixed at one end - One end is free and the guide rail is fixed at one end, while the other end is free. Fixed end bearings simultaneously bear axial and radial forces. This support method is used for short guide rails with small stroke or for fully closed-loop machine tools, because the mechanical positioning accuracy of this structure is the least reliable, especially for guide rails with a large aspect ratio (linear guide rails are relatively slender), and thermal deformation is very obvious. It is normal for a 1.5m long guide rail to change by 0.05-0.10mm in different cold and hot environments. However, due to its simple structure and easy installation and debugging, many high-precision machine tools still use this structure, but it is necessary to install gratings and adopt fully closed-loop feedback.

　　3.两端固定? ?导轨两端均固定。固定端轴承都可以同时承受轴向力，这种支承方式，可以对导轨施加适当的预紧力，提高导轨支承刚度，可以部分补偿导轨的热变形。? ?对于大型机床、重型机床以及高精度镗铣床常采用此种方案。但是，这种导轨的调整比较繁琐，如果两端的预紧力过大，将会导致导轨终的行程比设计行程要长，螺距也要比设计螺距大。如果两端锁母的预紧力不够，会导致相反的结果，并容易引起机床震动，精度降低。所以，这类导轨在拆装时一定要按照原厂商说明书调整，或借助仪器（双频激光测量仪）调整。

　　3. Both ends of the fixed guide rail are fixed. Fixed end bearings can simultaneously withstand axial forces. This support method can apply appropriate pre tension to the guide rail, improve the stiffness of the guide rail support, and partially compensate for the thermal deformation of the guide rail. This scheme is commonly used for large machine tools, heavy-duty machine tools, and high-precision boring and milling machines. However, the adjustment of this type of guide rail is relatively complicated. If the pre tension force at both ends is too large, it will result in the final stroke of the guide rail being longer than the design stroke and the pitch being larger than the design pitch. If the pre tightening force of the locking nut at both ends is insufficient, it will lead to opposite results and easily cause machine tool vibration, resulting in reduced accuracy. So, when disassembling and assembling such guide rails, it is necessary to adjust them according to the original manufacturer's instructions or with the help of an instrument (dual frequency laser measuring instrument).