mecalac 14 MBX, Handbook Of Repair

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3.5 Hydraulic system
Three completely independent circuits: hydrostatic transmission, equipment circuit, and steering and
slewing circuit.
3.5.1 Hydrostatic transmission
Reversible closed circuit, with declutching bypass valves in case towing is necessary.
- Transfer movement pump: ............................................................................................. 71 cm 3
- Transfer movement engine: ........................................................................................... 107 cm 3
- Axial piston engine and pump:
Variable displacement and axial piston motor and pump permitting the continuous variation of the
transmission ratio over the machine’s entire speed range. Automatic adjustment of the optimum
transmission ratio to suit the motion resistance and accelerator setpoint of the diesel engine: it
is automobile control.
- Selection of direction of travel:
( F ) “forward” or ( R ) “reverse” by electric control on the steering ”Commodo”, without being
obliged to stop.
- Two manual speed ranges operated by the selector:
This change of speed must be done when stationary, with the ‘Commodo’ in neutral ( N ) and the
brake pedal fully depressed.
• Selector OFF = Range 1 , “Site” speed,
• Selector ON = Range 2 , “Road” speed.
For each of these 2 speed ranges, it is possible to operate 2 speeds for both directions of travel
selected by the ‘Commodo’ electric control, i. e. in all 4 speeds:
• RANGE 1 : ( L ) speed from 0 to 4 kph,
( H ) speed from 0 to 12 kph.
• RANGE 2 : ( L ) speed from 0 to 10 kph,
( H ) speed from 0 to 30 kph.
Note: For Germany, between 0 and 20 kph.
Possibility of control in “loader mode” ( L ) or ( H ) and ( F ) or ( R ) using the right manipulator.
- Inching” slow approach control:
Allows reducing the displacement speed at a constant engine regime and therefore applying a
constant power to the wheels in both front/reverse directions.
- Handbrake (parking and emergency):
It works by lack of pressure on the integrated discs on the front axle.
- Hydrostatic foot brake:
Foot-operated control with inching device, main brake function and working brake function.
- Main brake:
In the initial part of its travel, it reduces the machine’s travel speed by means of the valve (inching
function), then if the braking pressure exceeds 13 bars it acts simultaneously on the integrated
discs on the front and rear axles (main brake function). This system increases the service life of
the brake discs.
- Working brake:
A switch locks the foot-operated control in the braked position and makes it possible to work by
releasing the brake pedal while at the same time having the brakes locked.
14MBX 30750
8 M1