Main Shaft And Bearing - Alamarin Jet COMBI-FRAME AJ 285 Repair Manual

Main shaft and bearing

Repair manual
2. Main shaft and bearing
The power from the engine that runs the jet is transmitted to the main shaft
using an intermediate shaft. The intermediate shaft is attached to the drive
flange in one end, and either the gear box or the engine flywheel adapter in
the other end. The intermediate shaft is often acquired and installed by the
manufacturer of the boat and can, therefore, not be discussed in detail in
this document. However, some central issues related to it are described at a
general level in the section 2.3.
The main shaft of the jet is a direct shaft (figure 1, point A), supported at
both ends with bearings. At the front end of the shaft is a drive flange (figure
1, point B), to which the intermediate shaft is connected. The shaft is also
equipped with an impeller (figure 1, point C), connected with a parallel key.
The impeller generates pressure as it rotates.
Figure 1. Main shaft and bearing
The front end has a double-cone angular contact ball bearing, receiving axial
thrust and radial loads in every direction. The bearing is inside the housing
(figure 1, point D), and it is oil-lubricated. The bearing housing seal on the
intake duct side is a mechanical rotary seal (figure 1, point E). The shaft seal is
on the engine room side.
The rear bearing (figure 1, point F) is attached to the stator. There is a needle
bearing, which is lubricated from the engine room with petroleum jelly, within
the housing. Alternatively, a water lubricated bearing can be used.
KM/285/EN/1.1.0
, page 25.
Intermediate shaft
3