Service manual

Avantra 36/44 Service Manual
2-20 Functional Analysis
Figure 2-9 Carriage assembly.
The carriage assembly consists of:
• Carriage housing with precision mounting interfaces for the bearing com-
ponents
• Optical system
• Friction wheel drive components
The carriage assembly uses a friction drive system with recirculating ball bearings
that ride on two rails mounted to the upper structure. This type of system makes
the carriage self contained.
2.13.1.1 Friction Wheel Drive Subsystem
The friction wheel drive subsystem consists of:
• Spin motor assembly
• Flywheel
• The digital and analog encoders
• Active preload system
The precision ball bearings in the carriage housing support the shaft; the friction
wheel rides along one of the fixed rails (guide rail) of the linear bearing guideway
system. Friction contact is maintained between the wheel and the guide rail
because of the gravity load of the carriage and an active preload element.