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MTZ Belarus Tractor hydraulic power steering
Forward-Motion hydraulic power
steering
The hydraulic power steering is intended for controlling the turning of
the steerable wheels and reducing the force to be applied to the
steering wheel for turning the tractor.
The hydraulic power steering consists of a metering pump (1), two
differential hydraulic cylinders (3) executing the turn, feeding pump
(2) driven from the engine and hydraulic fittings.
The hydraulic power steering oil tank is the right-hand section of the
oil tank (4) with the 25-micron filter of the working fluid.
Fig.1. MTZ Belarus Tractor steering
1 – metering pump; 2 – feeding pump; 3 – hydraulic cylinders; 4 – oil
tank.
Construction and Operation of the
hydraulic power steering
The direct-acting metering pump (1) is installed on the bracket of the
steering column; the turn hydraulic cylinder (3) – on the brackets
attached to the front axle and the feed pump (2) – on the engine.
The metering pump is connected to the chambers of the hydraulic cylinder
of turning, feed pump and oil tank via pipe-lines.
When in a straight-ahead motion, the cylinder chambers are closed by the
metering pump spool belts, and the oil fed from the feed pump and
brought to the metering pump returns to the oil tank.
When the steering wheel is turned, the metering spool-valve is displaced
providing in such a way for oil supply to the chambers of the hydraulic
cylinder of turning in the amount proportional to the angle of turn of
the steering wheel.
Recommendations for Operation of the
hydraulic power steering
When assembling the MTZ Belarus Tractor
hydraulic power steering:
- Install properly the oil pipelines and hoses in accordance with the
hydraulic diagram;
- Protect the connecting holes of the metering pumps, hydraulic
cylinders, poi pipelines and high-pressure hoses against penetration of
dirt;
- Prior to starting the engine, check the tightening of all the
connections of the hydraulic power steering hydraulic system;
- When tightening the fasteners, apply the required torque;
- Fill the oil tank to the upper limit as seen on the level indicator;
Bleed air from the MTZ Belarus Tractor hydraulic system.
To do this, proceed as follows:
- Start the engine. Turn the steering wheel in both directions 3-4 times
at the idling rotational speed of the engine without reaching the
extreme positions of turning of the steerable wheels.
- Add oil to the tank to the required level.
- Turn the wheels from one stop to an-other 2-3 times. Hold the steering
wheel at the extreme positions for 4...5 seconds.
- If necessary, eliminate the oil leaks and add oil to the top level of
the tank.
- Drive the figure of eight to check the operation of the steering
control.
Metering Pump
The metering pump consists of assembly I, distributor II, non-return
valve (9), two anti-hammer valves (7), relief valve (6) and two
anti-vacuum valves (8).
Fig.2. MTZ Belarus Tractor hydraulic steering
1 – stator; 2 – rotor; 3 – spool valve; 4 – power shaft; 5 – sleeve; 6 –
relief valve; 7 – anti-hammer valves; 8 – anti-vacuum valves; 9 –
non-return valve; 10 – body. I – pumping assembly; II – distributor
The Gerotor pumping assembly I consists of the stator (1) fixed on the
body and rotating rotor (2) connected to the spool valve (3) by the
power shaft (4).
The distributor II consists of the body (10),
sleeve (5) and spool valve (3) splined onto the tail-end of the power
shaft of the steering column:
- The relief valve (6) limits the maximum pressure in the pressure
mainline to within 17.5...18.0 MPa (175...180 kgf/cm2) in the hydraulic
power steering system with the double-rod hydraulic cylinder or to
within 14.0...14.5 MPa (140...145 kgf/cm2) in the hydraulic power
steering system with two hydraulic cylinders of steering control.
- The anti-hammer valves (7) limit pressure in the cylinder mainlines at
impact loads.
- The pressure setting of the anti-hammer valves is within 22.5...24.5
MPa (225...245 kgf/cm2).
- The anti-vacuum valves (8) make it possible to ensure the required
supply of the working fluid into the hydraulic cylinder in the emergency
mode and in case of operation of the anti-hammer valves.
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