IAI America RCP4W - Manual (Page 91)

6. Product Life
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6. Product Life
The mechanical life of the actuator is represented by the guide that receives the moment load mostly.
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”.
• “Static Rated Load” : Load applied while the actuator is stopped, as a result of which minor
pressure marks are left on the contact surface
• “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.
However, it is important to know the specific product life for the general-purposed industrial machines
also from the view of maintenance. The life of the guide is sufficient for the radial load, and is mostly
influenced by the moment load caused by the offset from the center of the guide.
The operation life is set to 5000km assuming 1.2 times of the load coefficient (safety margin) under the
allowable load moment. [For the allowable dynamic load moment, refer to 1.2 Specification.]
The formula for calculating the allowable dynamic load moment corresponding to a traveling life of
5,000km is shown below.
C
IA
=
M
50
f
W
×
50km
5000km
Calculate the life at the applicable moment using the formula below:
L =
C
IA
P × 5000km
1
3
C
IA
: Allowable dynamic load moment
f
W
: Load factor (= 1.2)
M
50
: Rated dynamic moment based on a survival probability of 50%
after 50km of traveling
L : Traveling life (survival probability of 90%)
C
IA
: Allowable dynamic moment
P : Applicable moment
3