When the ball screw is running, the temperature rise will affect the accuracy of the mechanical transmission system, especially the high-speed and high-precision machinery. The following factors affect the temperature rise of ball screw:

温升的因素基本是这三种：(1) 预压力 (2) 润滑 (3) 预拉。

There are three basic factors of temperature rise: (1) pre pressure (2) lubrication (3) pre tension.

导轨在安装时注意的事项

Matters needing attention during installation of guide rail

(1) 预压力的影响

(1) The influence of preload

为避免造成机械传动系统的任何失步，提高螺帽刚性是很重要的，然而要提高螺帽刚性，必须使螺帽预压力达 到一定水准。施加预压力于螺帽会增加螺牙的摩擦扭矩，并使工作时的温升提高。

However, it is very important to improve the rigidity of the nut system in order to avoid any loss of mechanical step. Applying pre pressure on the nut will increase the friction torque of the screw teeth and increase the temperature rise during operation.

导轨安装不好滚珠丝杆的影响

Influence of improper installation of guide rail on ball screw

(2) 润滑的影响

(2) Effect of lubrication

润滑油的选择直接影响滚珠丝杆的温升。HIWIN滚珠丝杆须採以油或油脂其中一项的润滑，一般建议以轴承 润滑油为滚珠丝杆油润滑，油脂则建议以锂皂基的油脂。油品黏度选用是依操作速度、工作温度及负荷情形来做 选择。说明油品黏度、工作温度与温升的关係和IKO自润滑滚珠花键原理是一样的。

The selection of lubricating oil directly affects the temperature rise of ball screw. HIWIN ball screw must be lubricated with one of oil or grease. Generally, bearing grease is recommended as ball screw oil, and lithium soap based grease is recommended as grease. The selection of oil viscosity depends on the operating speed, operating temperature and load. It shows that the relationship between oil viscosity, working temperature and temperature rise is the same as IKO self-lubricating ball spline.

当工作情况为高速低负载时选用低黏度油品；低速高负载时则建议使用黏度高油品。 一般来讲，高速时建议使用润滑油为40℃时黏度指数范围为32～68 cSt (ISO VG 32～68)(DIN  51519)；而低速时，建议使用的润滑油为40℃时黏度指数范围为90 cSt (ISO VG 90)以上。应用于高速且重负载，必须以强製冷却来降低温度，且可藉由中空螺杆通入冷却油来达到冷却效果。

When the working condition is high speed and low load, low viscosity oil is selected; when the working condition is low speed and high load, high viscosity oil is recommended. Generally speaking, it is recommended to use lubricating oil at high speed with viscosity index range of 32-68 CST (ISO VG 32-68) (DIN 51519) at 40 ℃; at low speed, it is recommended to use lubricating oil with viscosity index range of above 90 CST (ISO VG 90) at 40 ℃. For high speed and heavy load applications, the temperature must be reduced by forced cooling, and the cooling effect can be achieved by injecting cooling oil into the hollow screw.

(3) 预拉的影响

(3) The influence of pretension

滚珠螺杆温升时，热应力效应会使螺杆伸长，使螺杆的长度变得不稳定。其伸长量可藉由M40公式求出，此伸 长量可藉由预拉来做补偿；而预拉补偿的目标值就是图面所标示的负T值。过大的预拉会烧坏支撑轴承，因此HIWIN 建议採用小于5℃的预拉值，但若螺杆直径超过50mm时也不适合做预拉；螺杆直径大就需要大的预拉力，因此导致 支撑轴承过热而烧坏。

When the ball screw temperature rises, the thermal stress effect will make the screw elongate and make the screw length unstable. The elongation can be calculated by M40 formula, and the elongation can be compensated by pre stretching. The target value of pre stretching compensation is the negative T value marked on the drawing. Too large pre tension will burn the support bearing, so HIWIN suggests that the pre tension value less than 5 ℃, but it is not suitable for pre tension if the screw diameter exceeds 50 mm; large pre tension is required for large screw diameter, which leads to overheating and burning of the support bearing.