C4  Maintenance  5. Joint #1 
 
C Series Maintenance Manual Rev.2  63 
5.2  Joint #1 - Replacing the Reduction Gear Unit 
 
The shapes and replacement procedures of the reduction gear units vary depending on the specification type.   
The reduction gear units have the following two specification types which differ  depending on the time of 
shipment. 
Before performing maintenance, confirm the specification type of the reduction gear unit. 
 
 
A reduction gear unit consists of the following parts and accessories.  When replacing the reduction gear unit, 
be sure to replace these parts and accessories all together as a set. 
Reduction gear unit  : Wave generator, Flexspline, Circular spline 
Accessory  : Spacer, Grip ring (only for Specification type 1) 
For details, refer to C4 Maintenance: 17. C4 Maintenance Parts List. 
It is recommended to replace the O-ring when replacing the reduction gear unit. 
 
 
Parts 
Joint #1 reduction gear unit 
Joint #1 O-ring 
1 
1480857 
Tools 
Hexagonal 
wrench 
width across flats: 2.5 mm 
For M5 hexagon socket head set screws 
For M4 hexagon socket headcap bolts 
For M6 hexagon socket headcap bolts 
For belt tension adjustment