The failure phenomenon and specific reasons of ball screw pair in operation are as follows:

1、反向间隙大，定位精度差，加工零件尺寸不稳定。

1. Large reverse clearance, poor positioning accuracy and unstable dimension of machined parts.

滚珠丝杠副及其支撑系统由于长时间运行产生的磨损间隙，将直接影响数控机床的传动精度和刚性。一般故障现象有反向间隙大、定位精度不稳定等问题。根据磨损具体产生的位置，故障原因可分为以下几类：提高滚珠丝杆副精度的办法？ 滚珠丝杠支撑轴承磨损或轴承预加负荷垫圈配的不合适。滚珠丝杠双螺母副产生间隙、滚珠磨损。

The wear clearance of ball screw pair and its support system caused by long-time operation will directly affect the transmission accuracy and rigidity of CNC machine tools. The common faults include large reverse clearance and unstable positioning accuracy. According to the specific location of wear, the causes can be divided into the following categories: how to improve the accuracy of ball screw pair? The ball screw support bearing is worn or the preloading washer is not suitable. The double nut pair of ball screw produces clearance and ball wear.

2、滚珠丝杠副运动不平稳，噪音过大。伺服电机驱动参数未调整好。丝杠丝母润滑不好。滚珠丝杠弯曲变形。

2. The motion of the ball screw pair is not stable and the noise is too large. Servo motor drive parameters are not adjusted well. The screw nut is not well lubricated. The ball screw is bent and deformed.

滚珠丝杆副的常见故障如下：

The common faults of ball screw pair are as follows:

（1）过载问题

(1) Overload problem

滚珠丝杆副进给传动的润滑状态不好、轴向预加载荷太大、丝杠与导轨不平行、螺母轴线与导轨不平行、丝杠弯曲变形时，都会引起过载警声。一般会在CRT上显示伺服电动机过载、过热或过流的警声，或在电柜的进给驱动单元上，用指示灯或数码管提示驱动单元过载、过流信息。

When the lubrication state of the ball screw pair feed drive is not good, the axial preload is too large, the lead screw is not parallel to the guide rail, the nut axis is not parallel to the guide rail, and the lead screw is bent and deformed, the overload alarm will be caused. Generally, the alarm sound of overload, overheating or over-current of servo motor will be displayed on CRT, or the information of overload and over-current of drive unit will be prompted by indicator light or nixie tube on the feed drive unit of electric cabinet.

（2）爬行问题

(2) Crawling problem

爬行问题一般发生在启动加速段或低速进给时，多因进给传动链的润滑状态不好、外加负载过大等因素所致。尤其要注意的是，伺服电动机和滚珠丝杠连接用的联轴器，如连接松动或联轴器本身缺 陷，如裂纹等，会造成滚珠丝杠转动和伺服电动机的转动不同步，从而使进给运动忽快忽慢，产生爬行现象。

The creeping problem usually occurs when the acceleration section or low speed feed is started, which is mainly caused by the bad lubrication state of the feed transmission chain and the excessive load. In particular, if the coupling used for connecting the servo motor and the ball screw is loose or the coupling itself is defective, such as cracks, etc., it will cause the rotation of the ball screw and the servo motor to be out of sync, so that the feed movement will be fast and slow, and the phenomenon of crawling will occur.

（3）窜动问题

(3) The problem of movement

窜动问题是滚珠丝杠副进给传动的润滑状态不好、丝杠支承轴承的压盖压合情况不好、滚珠丝杠副滚珠有破损、丝杠支承轴承可能破裂、轴向预加载荷太小，使进给传动链的传动间隙过大，引起丝杠传动时的轴向窜动。

The problem of shifting is that the lubrication state of the feed transmission of the ball screw pair is not good, the gland pressing of the ball screw support bearing is not good, the ball of the ball screw pair is damaged, the ball screw support bearing may break, and the axial preload is too small, which makes the transmission clearance of the feed transmission chain too large and causes the axial shifting of the ball screw drive.