Rated Load

Basic Static Rated Load

(1) Definition of Basic Static Rated Load (C₀)

If a linear guide is subjected to excessive loads while stationary or in motion, or if it experiences significant impact loads, this can cause localized permanent deformation of the contact surfaces between the ball raceways and the steel balls; when the amount of permanent deformation exceeds a certain limit, it will impair the smoothness of the linear guide’s motion. The basic static rated load is the limit load that permits this amount of permanent deformation. By definition, it is the static load at which—under conditions where the direction and magnitude of the load remain constant—the total permanent deformation of the ball and raceway surfaces at the point of maximum stress is exactly one ten-thousandth of the ball’s diameter.

The values for the basic static rated load are listed in detail in the respective specification tables; users may refer to these tables to select a suitable linear guide. However, it is important to note that the maximum static load experienced by the selected linear guide during operation must not exceed its basic static rated load.

(2) Definition of Allowable Static Moment (M₀)

When the steel ball in the slider subjected to the maximum stress reaches the static rated load as defined above, the torque borne by the slider at that moment is referred to as the static rated torque. In the motion of a linear guide, this is defined in three directions: M_R, M_P, and M_Y:

(3) Static Safety Factor

When linear guides are used for slow motion or under conditions with low operating frequencies, the static safety factor must be considered. Depending on the specific operating conditions, different safety factors must be applied when calculating static loads; in particular, a higher safety factor is required when the guide is subjected to impact loads.

Table 1: Application of Static Safety Factors

OR

f_SL : Static Safety Factor

f_SM : Static Safety Factor (Moment Load)

C₀ : Basic Static Rated Load (kN)

M₀ : Allowable Static Moment (kN·m)

P : Working load (kN)

M : Static moment load (kN·m)

Basic Dynamic Rated Load

Definition of Basic Dynamic Rated Load (C)

The basic dynamic rated load is used to calculate the service life of a linear guide when it is subjected to a load and performs rolling motion. It is defined as the maximum load at which the linear guide has a rated life of 50 km (100 km for roller-type linear guides) under conditions where the direction and magnitude of the load remain constant. This value is listed in detail in the respective specification and dimension tables; users can use this value to estimate the rated life of the selected linear guide in advance.