4-7
Chapter 4 Periodic Inspections
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CAUTION
Harmonic drive
• Do not apply strong impacts on any part with a hammer, etc. Do not damage
or mark the parts by dropping. There is a risk of damage.
• The specified performance cannot be attained if a damaged part is used.
Continued use of a damaged part could lead to trouble such as rupture.
Harmonic grease HC-1A (Harmonic Drive Systems) is used to lubricate the har-
monic drive used for the R-axis (ZRL, ZRH, ZRF unit) speed reduction gear. The
life of the harmonic drive could be shortened if this grease deteriorates.
Determine an inspection interval at every three years or to suit the usage condi-
tions, and replace the grease.
The ZRS unit's R-axis also uses a harmonic drive, but the grease does not need to
be replaced.
8-1 Harmonic grease replacement period
The harmonic grease should be replaced when the total number of wave genera-
tor rotations reaches 1.5 × 108 times (at -10°C to +40°C). Thus, the replacement
period will differ according to the following usage conditions.
n : Number of arm movements in one minute
θ: Average arm rotation in one movement
N : 1/deceleration rate
h : Number of operation hours per day
D : Number of operation days per year
The method of calculating the replacement period using the following conditions
is shown as an example.
n : 10 times
θ: 1/4 rotation
N: 80
h : 24 hours/day
D : 240 days/year
Replacement period = 1.5 × 108/ ( n × 60 × h × D × N × θ )
= 1.5 × 108/ ( 10 × 60 × 24 × 240 × 80 × 1/4 )=2.17 years