Sam Horizon, Руководство оператора, Страница: 35 / 73

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A slow speed high torque Wheel Motor is mounted behind each wheel of the machine. Each Motor has
numerous pistons operating on numerous cam faces. As such, up to eighty piston strokes are therefore
required to turn the wheel once, making slow speed operation extremely smooth and efficient. For 'road' use,
half the pistons are neutralised, therefore, for the same amount of oil the wheel will turn twice as fast but with
half the power.
The speed of operation depends entirely upon the flow from the pump. Maximum field speed is up to 20kph
(12 mph) but like any tractor the slower it travels, the more power it has.
The hydrostatic pump carries out the 'primary' braking function. It will produce braking torque equal to the
driving torque, since no freewheel action can occur within a hydrostatic wheel motor.
A mechanical disc brake is an integral part of the wheel motors. This 'secondary' mechanical braking system
is for
parking / emergency use only (unless dynamic brakes are fitted).
Should the Park Brake be operated while the machine is moving, serious damage will result.
These brakes are failsafe in their operation, spring on - pressure off, and are held off with 'boost pump'
pressure, as such, they will be automatically applied when the engine is stopped or when 'boost' pressure fails
i.e. if a hydraulic hose fails or from lack of oil in the tank.
The permanent 4WD system employed on all SAM sprayers maximises high tractive effort with more than
adequate braking ability and a 'torque split' effect by controlling oil flow to the front and rear axles is a standard
feature of all Horizon Sprayers.
TRANSMISSION - HYDROSTATIC WHEEL MOTOR
3-3
A self-levelling suspension system is fitted to the SAM 'Horizon' Sprayers. Normal suspension is provided by
hydraulic rams and gas accumulators fitted at each corner of the machine. The accumulator pre-charge has
been set at the factory and needs no further adjustments. The pre-charge should be checked by a competent
person every 2000 hours.
The rear axle is of the trailing arm type to reduce front end nodding. For safety reasons, it is not independent,
therefore the machine will always follow the attitude of the rear axle.
The front axle is free to articulate ensuring that all wheels stay in contact with the ground under normal
conditions.
Two leveling valves are fitted to the chassis near each axle. A sensing arm joining each valve to its respective
axle determines the correct ride height. Oil is moved 'into' or 'out of' the rams to maintain the same height
above the ground whether the tank is full or empty or the booms are open or closed.
The front tripod bearing should be inspected on a regular basis and at least every 250 hours along
with the Panhard rod. Weekly greasing is essential. If a knocking sound is heard from underneath the
Cab then the front tripod bearing should be replaced
IMMEDIATELY !
The only maintenance on the rear being the regular greasing of the swinging arm bushes and the removal of
mud and stones, which accumulate on top of the swinging arm frame. Should this accumulation be allowed to
dry then the rear suspension system could become inoperative.
SUSPENSION
Working in a similar manner to a vehicle anti-lock braking system. A sensor at each wheel measures the
speed of rotation of that wheel via electronic pulses. If one wheel should speed up and exceed the averages
of the other three wheels by a pre-determined amount, the oil to that wheel is stopped. The wheel is then
allowed to rotate via a modulating valve at the average speed of the other three wheels.
The anti-slip ECU has four LEDs (wheel sensor connections) which should be flashing green (only when
moving). A change of colour identifies a fault - contact SAM.
SMART DRIVE (Electronic Anti-Slip System) - Optional