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.25-micron filter of the working fluidThe hydraulic power steering oil tank is the right-hand section of the oil tank (4) with the 25-micron filter of the working fluid

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 wheelRecommendations for Operation of the hydraulic power steering

When assembling the 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 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)

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 thehydraulic power steeringsystem 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

TROUBLESHOOTING

Problems and probable causesCounter measures

1. Steering wheel is very heavy to turn

a) Poor assemble between steering column and unit. Spline of column and unit are assembled tightly. Spool of unit is seized by spline of column Poor rotation of column

b. Insufficient pump pressure or fluid volume Check pump delivery (Unit volume120 rpm1.15) Check oil tank fluid volume Check pump pressure

c. Trouble internal steering unit valve Low setting pressure of relief valve Ball-nut heavy to work

d. Trouble machine mechanism. Poor link work Excessive sector gear pre-load

Replace column spline

Check column assembly face and spline length (MAX 6.5) Replenish oil or Exchange

-Exchange pump

-Replenish oil -Adjust relief pressure

Adjust fluid level properly Wash clean or replace

Wash and replenish oil -Adjust backlash

2. Return to neutral is too slow

a. Poor assemble steering column and unit Poor assemble to center between column and unit Column assembly face depressed unit bushing

b. Depressed control set (spool+sleeve) Excessive fluid volume Excessive pressure Dust

c. High pressure ratio of "T" port (tank port) Tank port hall is small Tank port pipe is linked to other lines

3. Free play of steering wheel

a. Too low elastic of centering spring( Remove P port pipe line and check left and right turning) Damaged spring or poor elastic

b. Depressed control set Excessive fluid and pressure Depressed by foreign material Dpressed from external when assemblewith column

Loosen the bolt and fix again with center

-Replace column or repair

Adjust fluid level properly Adjust pressure Wash

MAX. Pressure ratio 20 bar Wash and clean pipe line Separate unit pipe line and reinstall

Replace spring

Adjust fluid level and pressure properly Wash Check column and adjust

4. Steering wheel resistance with turning

a. Worn of spline gear columnb. Depressed control set

c. Air trapped in cylinder and pipe lined. Excessive backlash columne. Poor turning of column,or wear of bearing

Replace column -Wash,and Adjust fluid level and pressureproperly -Deflate the air -Adjust column -Replace column and replenish oil

5. Too much free play of steering wheel(Rough touching on tire causes vibration)

a. Air trapped in steering cylinder and pipe line.b. Worn ball bearing

Deflate the air -Replace

6. Free play steering wheela. Insufficient oil in the tankb. Worn,damage steering cylinderc. Loose spacer in unit

Replenish oil Replace oil seal and cylinder assemble spacer parts.

7. Kick-back of steering wheel

a. Loose check valve in "P" port or don'toperateb. Trouble in system

Adjust check valve

consult workshop

8. Serious kick-back each side

a. Poor assemble the gyrotor lower the unit

Reassemble

9. Steering wheel is very heavy to begin turning

a. Oil density is too high or cool

Replace oil

10. External Oil leakage

a. columnb. End cap gyrotorc. Tightening Bolt

Replace oil seal,slide ring Replace o-ring Replace copper washer(Torque 1st:175 f. 2nd:280 f)