Yamaha 3-axis model Manual Do Utilizador

11-39

Replacement period
The harmonic drive replacement period is determined by the total number of
wave generator rotations. A calculation example is shown below.
The recommended harmonic drive replacement period is 8.4

×10

8

 rotations (at

usage atmospheric temperature range 0

°C to +40°C).

The harmonic drive should be replaced earlier if the robot operation duty is high
or if the temperature conditions are poor.

[Replacement period]

=8.4

×10

8

/(n

×60×h×D×N×θ) years

n

: Number of robot movements in one minute

θ

: Average axis rotation in one movement

N

: Deceleration rate (50 for ZRS R-axis)

h

: Number of operation hours per day

D

: Number of operation days per year

(Example) The YK500X X-axis harmonic drive replacement period when the

axis rotates an average quarter turn every movement and the robot
moves ten times in one minute. (Operation hours: 24 hours/day,
number of operation days: 240 days/year)

n

:  10

θ

: 0.25

N

:  50

h

:  24

D

: 240

[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

Consult with YAMAHA when actually replacing the harmonic drive.