BZZ1,BZZ2,BZZ3 series SCU offers the
advantages as follows:
This kind of SCU series can help you reduce the machinery cost without mechanical linkage device, and can offer reliable and light structure.
This kind of SCU series can operate more flexible with light steering torque.This kind of SCU series can offer emergent manual steering in case of engine failure.This kind of SCU series can be steering at the continuous speed with less steering torque.This kind of SCU series can offer various hydraulic system and different mounting choice.This kind of SCU series can link various steering pump and hydraulic steering system.
Hydraulic Steering Unit (BZZ1, BZZ2, BZZ3)
Hydraulic steering control units (BZZ)
BZZ1, BZZ2, BZZ3 Hydraulic steering control units(SCU), new design, better performance. Widely applied to low speed and heavy load vehicles E.g. construction machinary, forklift, tractor, harvester and helm control etc.
The advantages of the hydraulic steering control units:
Note 1: represents Function Code, BZZ2 can be chosen for SCU with the displacement of 50-200mL/r. BZZ1 or BZZ3 can be chosen for SCU with the displacement of 50-1000mL/r.
Note 2: “Flow” that we suggest to use is the flow of 1.25 times as much as that at the steering wheel’s rotation speed of 60 r/min. If the design of the system can't meet the requirements, the flow is allowed to be adjusted a little bit.
The installation and use of full hydraulic steering note
1 installation precautions:
2 oil flow rate considerations:
3 other matters needing attention:
Troubleshooting of Metering Pump
|Heavy turning of wheel.||1. lnsufficient oil pressure or no oil
2. Relief valve sticking when open orthe valve pressure is too low.
3. Blocked Ls orifice or dirt particles delaying spool movement in flow amplifier.
5. Misplaced anti-cavitation ball in steering unit.
2. Repair, clean and reset the reliefvalve.
|"Motoring" - steering wheel turning by itself.||1. Leaf springs have sagged and thus have reduced elasticity or no elasticity at all (broken springs rotherwise).
2. Squeezed spool/sleeve.Possible
insufficient spool/sleeve clearance.
|1. Replace leaf springs in control unit.
2.Contact your dealer.In the meantime,
lower the relief valve setting.
|Repeated steering wheel corrections required.
lmpossible to make steering go to neutral or right on own accord.
|1. Leaf springs without elasticity or broken.
2.Steering column out of alignment with steering unit.
3. Insufficient clearance between steering column and coupling.
1. Replace leaf springs in control unit.
3. Adjust the clearance.
|Backlash.||1. Splines of cardan shaft worn or broken.
2.Leaf springs without elasticity or broken.
|1. Replace cardan shaft.
2. Replace leaf springs in steering unit.
|Shimmy - abnormal
vibration of steering (tire pattern can cause vibration)
|1. Air accumulation in steering system.
2. Worn mechanical connections and wheel bearings.
3. Leaky dual shock valves and suction valves or broken springs.
|1. Bleed the cylinders and find the source of the air accumulation and have it removed.
2. Replace worn parts.
3. Repair or replace dual shock valves,suction valves or the springs.
|The steering wheel can be turned continuously without turning the wheels.
||1. No oil in the tank.
2. Steering cylinder piston seals leaking badly.
3. Shock valve failure.
|1.Fill system with clean oil and bleed the system.
2.Repair or replace cylinder(s).
3. Remove shock valves and repair or replace, then reset pressure level.
|The operator cannot feel resistance when the steered wheels turn to the stops.||1. Shock valves are set to approximately the same setting as steering PRV.
2.Dirt particles causing shock valve erratic operation.
|1. Adjust shock valve settings to at least 500 psi (34 bar) higher than steering PRv setting.
2.Clean system and fill with clean oil.
|steering wheel in both steering wheel in both directions.||1. lncorrect setting of cardan shaft and gear wheel setting (timing).||1. Adjust setting (timing).
|Kickback from system.||1.Dirt particles delaying spool movement in flow amplifier.
||1.Remove and overhaul flow amplifier.
Sample test oil to determine contamination source. Clean system,change filter elements and fill withfresh oil.
|Slow steering.||1. lnsufficient oil to the steering unit due to defective or worn pump.
2. Weak or damaged priority valve spool bias spring.
|1.Replace the pump.
2. Check or replace spring.
|The steering wheel does not pass to neutral
position - tendency to "motor."
|1. Dirt particles between spool and spring.
2. Squeezing between spool and sleeve caused by a too-high system pressure.
3. Leaf spring broken or without elasticity.
4.Mechanical binding in steering column.
|1.Clean spool and sleeve, or replace steering unit.Clean entire system.
2.Adjust pump pressure to the correct value at steering PRV.
3. Replace with new springs.
4. Correct and adjust where necessary.
|When turning the steering wheel, the steered wheels are
activated in the opposite direction.
|1. The hydraulic hoses to the steering cylinders have been reversed.
2. Incorrect mounting and setting of cardan shaft and gear wheel set.
|1. Correctly connect the hoses.
2.Correct the setting.
|Steering power too low (possibly to one side only).||1.Pump pressure too low.
2.Malfunctioning shock valve.
|1.Correct the pump pressure or adjust the steering PRV in the flow amplifier valve.
2.Remove and repair or replace shock valve.
|Leakage at input shaft,end cover on gear wheel set.||1. Defective shaft seal.
2. Screws have come loose.
3. Defective discs or O-rings.
|1. Replace shaft seal.
2. Tighten the screws to 266 in-lb (3 N-m).
3. Replace discs or O-rings.
|1. Dust seal ring||12. Set of springs||24. Name plate|
|2. Housing, spool and sleeve.
Check valve and the seats for relief and shock valves are locktited.
|13. Cardan shaft||30. Complete relief valve|
|3. Ball 8.5 mm [0.33 in]||14. Spacer||31. Spring wire|
|4. Thread bushing||15. O-ring||32. Complete shock valve|
|5. O-ring used with kin-ring (item 6)||16. Distributor plate||33. Ball 3/16 in|
|6. Kin-ring||17. Gearwheel set||34. Rolled pin|
|7. Bearing assembly||18. O-ring||35. Ball|
|10. Ring||19. End cover||36. Bushing|
|11. Cross pin||20. Washer||38. Spring|
|22. Special screw||39. Kin ring|
|23. Screw||40. O-ring|