Yamaha YK-XR Series, Installation Manual

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5
Har
monic drive r
eplacement period
5-2
2. Replacement period
The harmonic drive replacement period is determined by the total number of turns of the wave generator
used in the harmonic drive. It is recommended to replace the harmonic drive when the total number of turns
has reached 8.4×10
8
(at ambient operating temperatures of 0°C to +40°C). This means that the replacement
period will differ depending on the following operating conditions. If the robot operation duty ratio is high or
the robot is operated in environments at higher temperatures, the harmonic drive should be replaced earlier.
Replacement period = 8.4×10
8
/(n×60×h×D×N×
θ
) years
where n : Number of axis movements per minute
θ
: Average turn per axis movement
N : Speed reduction ratio
h : Operation time per day
D : Operation days per year
For example, when the robot is used under the following conditions, the replacement period for the
X-axis harmonic drive of the YK-XR series robots can be calculated as follows.
n : 10
θ
: 0.25
N : 50
h : 24 hours per day
D : 240 days per year
Replacement period = 8.4×10
8
/(n×60×h×D×N×
θ
)
= 8.4×10
8
/(10×60×24×240×50×0.25)
= 19.4 years
Harmonic drive speed reduction ratio
Robot model X-axis Y-axis
YK400XR 50 50