When the linear guide rail is subjected to load and is moving, the surface of the bead and the steel ball are constantly subjected to cyclic stress. Once the critical value of rolling fatigue is reached, the contact surface will start to be fatigue-damaged and the fish scale will appear on some surfaces. The peeling phenomenon of the sheet, this phenomenon is called surface peeling. The definition of life is the total running distance of the bead surface and the steel ball when the surface is peeled off due to material fatigue.
2. Rating life
The life of linear guides is highly dispersible. Even if the same batch of products are used under the same motion conditions, the service life will be different; this is mostly due to the inherent changes in the fatigue properties of the material itself. Therefore, in order to define the life of a linear guide, it is generally based on the rated life; it is defined as: a batch of the same product, operating under the same conditions and rated load one by one, 90% of which have not achieved surface peeling Running distance.
3. Calculation of life
The life of the linear guide will vary depending on the actual working load. The basic dynamic load rating and working load of the linear guide can be used to calculate the service life. Linear Guides
4. Life factor
(1) Hardness coefficient (fh)
The hardness of the bead contact surface hardness is required to be hrc58-62 at a certain hardening depth. If the hardness value cannot reach the required level, the rated load and service life of the linear guide rail will be reduced. At this time, the dynamic and static rated load is the size table. The column value is then multiplied by the corresponding hardness factor.
The linear guide rail hardness requirements of hiwin are all above hrc58, so fh is 1
Linear guide (2) temperature coefficient (ft)
The system temperature will affect the material of the linear guide. When the temperature is higher than 100 °c, the rated load and service life of the linear guide will be reduced. At this time, the dynamic and static rated load is the size of the dimension table and multiplied by the corresponding temperature coefficient. . Since some accessories are made of plastic materials that are not resistant to high temperatures, the recommended temperature should be less than 100 °C.
(3) Load factor (fw)
The load acting on the linear guide is not only the self-weight of the device itself, the inertia load at the time of starting and stopping, but also the moment load due to the suspension, as well as the shock and shock loads accompanying the motion. This type of load is not easy. Calculate, based on experience, depending on the load situation and speed of use, it is recommended to multiply the calculated load value by the corresponding load factor.