IAI America RCA2-SA6R - Manual (Page 68)

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12. Life
12. Life
One factor that affects the traveling life of an actuator is “Rated Load.”
There are two types of rated loads: “Static Rated Load” and “Dynamic Rated Load.”
x “Static Rated Load”:
Load applied while the actuator is stopped, as a result of which minor
pressure marks are left on the contact surface
x “Dynamic Rated Load”: Load under which the actuator can travel for a specified distance and still
meet a specified probability of survival defined by no damage to its guide.
Manufacturers of guides indicate the life of each guide by a dynamic rated load based on a probability of
survival (no damage to the guide) of 90% after 50 km of traveling.
With industrial equipment, however, dynamic rated loads must be defined based on longer traveling
distance of 5,000 km to 10,000 km given the moving speed, operating ratios and other operating
conditions of these equipment.
Also note that guides are generally designed with a sufficient life against radial loads. Moment loads that
are applied at positions away from the guide center are most damaging to guides.
The traveling life is calculated by assuming that the actuator travels 5,000 km while receiving the
allowable load moment, based on a load coefficient of 1.2.
[For the allowable dynamic load moment, refer to 6, “Specifications.”]
The formula for calculating the allowable dynamic load moment corresponding to a traveling life of 5,000
km is shown below.
3
1
50
IA
km 5000
km 50
x
fW
M
C ¸¸¹
·
¨¨©
§
Calculate the life at the applicable moment using the formula below:
km 5000 x
P
C
L
3
IA
¸¸¹
·
¨¨©
§
L: Traveling life (survival probability of 90%)
C IA: Allowable dynamic moment
P: Applicable moment
C IA: Allowable dynamic load moment
:fW: Load factor (= 1.2)
:M 50: Rated dynamic moment based on a
survival probability of 50% after 50 km of
traveling