LINEAR GUIDE TRH-F
High Assembly, Flange Type
TRH-F features low friction, small contact point and low temperature during operating, it only requires low driving force to operate, extending its' service life. TBI's exclusive patent delivers stability by increasing the depth of material and self-aligning balance load rate in all directions, increasing the accuracy.
When determining a model that would suit your service conditions for a linear motion system, the load carrying capacity and service life of the model must be considered. To consider the load carrying capacity you should know the static safety factor of the model calculation based on the basic static load rating. Service life can be assessed by calculating the nominal life based on the basic dynamic load rating and checking to see if the obtained value meet your requirements.
The service life of a linear motion system refers to the total running distance that the linear motion system travels until flaking (the disintegration of a metal surface in scale-like pieces) occurs there to as a result of the rolling fatigue of the material caused by repeated stress on raceways and rolling elements.
Basic Load Rating : There are two basic load ratings for linear motion systems : basic static load rating (Co), which sets the static permissible limits, and basic dynamic load rating (C).
■ 1-3-1 Basic Static Load Rating (Co)
If a linear motion system, whether at rest or in motion, receives an excessive load or a large impact, a localized permanent set develops between the raceway and rolling elements. If the magnitude of the permanent set exceeds a certain limit, it hinders the smoothness of the motion system.
The basic static load rating refers to a static load in a given direction with given magnitude such that the sum of the permanent set of the rolling elements and that of the raceway at the contact area under the most stress is 0.0001 times greater than the rolling element diameter.
In linear motion systems, the basic static load rating is defined as the radial load. Thus the basic static load rating provides a limit on the static permissible load.
■ 1-3-2 Basic Permissible Moment (MX, MY, MZ)
When a Linear Guide gets a force that makes the balls distorted to 1/10,000 of their diameter, we call the force as basic static permissible moment. Values of MX, MY, MZ are shown on Fig 1.3.1, which suggest 3 axis of moment on a Linear Guide slide.
■ 1-3-3 Static Safety Factor fS
A linear motion system may possibly receive an unpredictable external force due to vibration and impact while it is at rest or is moving or due to inertia resulting from start and stop. It is therefore necessary to consider the static safety factor against operating loads like these. The static safety factor (fs) indicates the ratio of a linear motion system load carrying capacity 【basic static load rating CO】 to the load exerted there on.
To calculate the applied load on Linear Guide, mean load and static safety factor must be obtained in advance. In the working environment with high intensity while start and stop, cantilever or cutting, a unexpected heavy load may occurs, therefore the maximum load must be acquired. Datum values of static safety factor are shown below;
Table 1.3.1 Static Safety Factor fs
|Machine Used||Loading Conditions||fs lower limit|
|Ordinary Industrial Machine||Receives no vibration or impact||1.0-1.3|
|Receives no vibration or impact||2.0-3.0|
|Machine Tool||Receives no vibration or impact||1.0-1.5|
|Receives no vibration or impact||2.5-7.0|