892-0000010B OM
89
3.3 Gearbox
3.3.1 General information
The gearbox (GB) is a part of the tractor transmission and serves to change gear
ratios of the transmission and ensure the reversal of the tractor movement.
In addition, the design of the gearbox provides a drive for a ground-speed rear and
lateral semi-continuous power take-off shaft (PTO), and also provides the possibility of ob-
taining additional speeds in the first and second gears of forward and reverse when the
tractor is equipped with a creeper (hydraulic creeper).
On the BELARUS-892/892.2 tractors, it is possible to install either a creeper (hydrau-
lic creeper) or a lateral semi-continuous PTO. Both the creeper (hydraulic creeper) and the
lateral semi-continuous power take-off shaft are attached to the left side plane of the gearbox
instead of the cover. Subsection 3.3 "Gearbox" contains a technical description of the gear-
box with creeper drive. The drive of the lateral semi-continuous PTO is presented in sub-
section 3.6 “Lateral semi-continuous power take-off shaft”.
The BELARUS-892/892.2 tractors are equipped with a mechanical fixed-ratio two-
range gearbox with a right-hand gearbox control lever. The following versions of the gearbox
are provided:
- GB 9F/2R with a mechanical increasing gear unit;
- GB 9F/2R with a mechanical reducing gear unit;
- GB 9F/2R with a synchronized reducing gear unit;
- GB 9F/9R with a reverse gear unit.
The gearbox, shown in Figure 3.3.1, is a complex unit consisting of mechanisms of
two groups. The first group - the mechanical transmission unit - includes mechanical toothed
gears that serve to transmit and transform the power flow. The second group - gearbox
control - includes lever mechanisms, the design of which provides the operator with high-
quality gearbox control (selection of the required gear in the gearbox, its reliable engage-
ment and the exclusion of self-disengagement).
3.3.2 Mechanical transmission unit
The gearbox mechanical transmission unit consists of primary shaft 34a and second-
ary shaft 6 coaxially located in gearbox housing 29 (Figure 3.3.1), as well as intermediate
shaft 32 and shaft of the 1st gear and reverse gear 27, parallel to them (Figure 3.3.2) .
Primary shaft 34a (Figure 3.3.1) is mounted on two ball bearings. One of the bearings
is located in cage 36a, which is installed in the bore of GB housing front wall 29 and is
attached to it with bolts. The second one is in the bore of secondary shaft 6. On the splines
of the front console of the primary shaft, driven gear of the reducing gear unit 35a is installed
rigidly. In the span between the primary shaft supports, double-rim drive gear of the 4th and
5th speeds 1 and drive gear of the 3rd and 6th speeds 5 are installed, which are able to
slide along the axis of the shaft on its splines.
The design of the front part of the primary shaft of the tractor gearbox 9F/9R equipped
with a reverse gear unit is shown in Figure 3.3.2. It has the following differences compared
to the 9F/2R gearbox discussed above with a mechanical increasing gear unit (Figure 3.3.1).
Driven gear of the reverse gear unit 35b (Figure 3.3.1) is mounted on the smooth
journal of front console of the gearbox primary shaft 34b and has the ability to rotate freely
on a roller bearing. Gear 34b is in constant engagement with the large crown of intermediate
gear of the gear unit 31.
To Next Page
Loading...
