- 10 -
3.4 Sound of bearing (Grease replenish type)
Sound of bearing during operation is classified as follows.
(1) Normal sound
The normal sound is continuous one. The race sound, jarring sound and retainer sound are
considered as normal. The jarring sound may be misunderstood as an abnormal noise but it
does not mean the abnormality of bearing. The jarring sound dies away temporarily when the
grease is injected in general.
The jarring sound may be generated in the following cases.
1) In case of bearing clearance C3 or C4 for high speed machine
2) In case of cylindrical roller bearing
3) In case of operation in winter of low ambient temperature and of the beginning of operation
after long stoppage.
(2) Abnormal sound
1) Flaw noise or dust noise, etc. are abnormal sound.
2) Abnormal sound is discontinuous and in some cases it accompanies vibration.
3)When abnormal noise sounds, inject new grease and observe change in sound and
temperature for a while. If abnormal noise does not stop, the bearing should be replaced.
4. Checking of accessories
For checking of accessories of electromagnetic brake, speed reducer, etc., see the Instruction of
Manual for accessories of the separate volume.
5. Service life of main accessory parts
Some parts of motor have their service life limit. It differs depending on the service
environment/conditions and therefore, carry out checking or replacement of parts making the
undermentioned service life limit as a criterion.
5.1 As to motor related parts
(1) Motor bearing (at ambient temperature of 40°C or lower and speed of 1800 r/min)
1) Grease replenish type bearing ..... About 50,000 hours
2) Shielded bearing .................. About 32,000
～
47,000 hours
・
Sealed grease is of Multemp SRL of Kyodo Yushi, or equivalent.
・
Life of shielded bearing is determined depending on the life of sealed grease. Life of
sealed grease is affected by the ambient temperature and is shortened about 1/1.5 every
time the ambient temperature rises 10°C from 40°C.
(2) Fan motor .......... About 3
～
4 years (at ambient temperature of 40°C or lower)
(3) Pulse oscillator ... About 4
～
5 years (at ambient temperature of 40°C or lower and speed of
1800 r/min)
(The shielded bearings of fan motor and pulse generator will reach the limit of their service life.
This limit differs depending on the ambient temperature.)
(4) V ring .................... About 25,000 hours
(It is recommended to also replace the V-ring when the encoder is replaced.)
5.2 Helical speed reducer (at ambient temperature of 40°C)
(1) Each bearing ....... About 25,000 hours
(2) Oil seal .................About 10,000
～
15,000 hours as a criterion (Life differs greatly depending on
the environmental conditions for use.)
(3) Replacement cycle of lubrication oil
First time
: 500
～
1,000 hours after starting of operation.
Subsequently : Every 2,500 hours.
