Symbols used in this literature.................................................................................................................................................... 4
Parts list................................................................................................................................................................................................6
OSQA and OSQB parts list........................................................................................................................................................6
OSQ spare parts list.................................................................................................................................................................... 8
Removing end cover at PP-connection................................................................................................................................. 12
Removing end cover at LS-connection..................................................................................................................................13
Housing and end cover with accessories..............................................................................................................................16
Spools with accessories............................................................................................................................................................... 17
Priority valve spool number of orifices...................................................................................................................................17
Shock and suction valves............................................................................................................................................................ 23
Inspection and replacement......................................................................................................................................................24
Installing OSQB back pressure valve.......................................................................................................................................32
Installing PP end cover.................................................................................................................................................................34
Installing LS end cover................................................................................................................................................................. 37
Set-up for testing........................................................................................................................................................................... 40
Steering test using steering unit type OSPBX LS................................................................................................................40
Pilot relief valve...............................................................................................................................................................................41
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Service Manual
OSQA/OSQB
Introduction
Safety precautions
Always consider safety precautions before beginning a service procedure. Protect yourself and others
from injury. Take the following general precautions whenever servicing a hydraulic system.
Warning
Unintended Machine Movement
Unintended movement of the machine or mechanism may cause injury to the technician or bystanders.
To prevent unintended movement, secure the machine or disable / disconnect the mechanism while
servicing.
Warning
Flammable Cleaning Solvents
Some cleaning solvents are flammable. To eliminate the risk of fire, do not use cleaning solvents in an
area where a source of ignition may be present.
Warning
Fluid under Pressure
Escaping hydraulic fluid under pressure can have sufficient force to penetrate your skin causing serious
injury and/or infection. This fluid may also be hot enough to cause burns. Use caution when dealing with
hydraulic fluid under pressure. Relieve pressure in the system before removing hoses, fittings, gauges, or
components. Never use your hand or any other body part to check for leaks in a pressurized line. Seek
medical attention immediately if you are cut by hydraulic fluid.
Symbols used in this literature
Warning
Personal Safety
Protect yourself from injury. Use proper safety equipment, including safety glasses, at all times.
Warning
Product Safety
Steering valves are safety components and therefore it is extremely important that the greatest care is
taken when servicing these products. There is not much wear on a steering valve and therefore they
normally outlast the application they are built into. Therefore the only recommended service work on
steering valves is:
•
Changing seals and o-rings
•
Disassemble, clean, and assemble if contaminated
•
Hydraulic testing, including valve setting
Non removable part, use a new partNote correct orientation
External hex headMark orientation for reinstallation
Internal hex headTorque specification
Lubricate with hydraulic fluidPress in - press fit
Inspect for wear or damagePull out with tool - press fit
Unscrew plug (37.1) from check valve using a 4 mm Hex key. and a 17 mm socket spanner.
a) Remove spring (37.2) and ball (37.5) from valve seat (37.4).
Dismantled amplifier spool
Shock and suction valves
Shock valves are assembled into the OSQ, and cannot be adjusted. Preadjusted shock valves can be
bought as spare parts, see OSQ spare parts list on page 8. Replace shock and suction valves if polluted.
Replacing O-rings is recommended.
Shock and suction valve assembly (left) with O-ring dismantled (right)
1. Place O-ring (20.11) on shock and suction valve cartridge (20).
2. Place O-ring (37.3) on valve seat/housing (37.4).
a)
Place housing in a 17 mm socket spanner.
b)
Place ball (37.5), spring (37.2) and plug (37.1) in housing (37.4) and tighten, using a 4 mm
Hex key and a 17 mm socket spanner, 5 ± 1 N·m [45 ± 10 lbf·in].
3.
Place orifice (41) in plug (40) and tighten in the pin hole, using a 4 mm Hex key and a mandrel,
5 ± 1 N·m [45 ± 10 lbf·in].
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Service Manual
OSQA/OSQB
Assembly
Assembling amplifier spool
4.
Place check valve (37) in spool (12) and tighten in the pin hole, using a 13 mm socket spanner and
a mandrel, 20 ± 3 N·m [177 ± 27 lbf·in].
Place inner spool in the correct position.
When assembling OSQA 5 and OSQB 5 there are two ways of placing the inner spool, only one is correct.
The pilot channel which faces upwards must be lined up with one of the 5 amplification holes in the
outer spool.
Inner spool in correct position
1. Guide inner spool (14) into outer spool (12).
2. Place the pin (38) through outer (12) and inner (14) spool.
Screw in the seat (21) using a 6 mm socket spanner, 20 ± 3 N·m [177 ± 27 lbf·in].
3.
Place O-ring on adjusting screw (23), then screw in, using a 6 mm Hex key.
After entire assembly of the steering valve, make the pressure setting on a test panel according to
valve setting specification, see Testing on page 40.
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Service Manual
OSQA/OSQB
Assembly
4. Place washers 8x (80) on screws 8x (81).
a) Place the 2 screws with washers in end cover (66), see Exploded view on page 6.
Make sure that all O-rings stay in place. The two screws must screw in with fingers only, so that
the end cover stays in parallel with flange area of the housing only, with distance for
compressing the O-rings less than 1 mm.
b)
Screw in screw (83) with washer (82) using a 10 mm Hex key until end cover is in place.
Screw in remaining six screws (81) with washers (80) using a 13 mm socket spanner, 25 ±
5 N·m [221 ± 44 in·lbf] or 80 ± 10 N·m [708 ± 89 in·lbf] for the 10 mm Hex key.
1. Place spring stop (27) on the directional spool (25).
2. Place O-rings, 2x (57) and 2x (58) and spring stop (10) in end cover (65).
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Service Manual
OSQA/OSQB
Assembly
3. Place spring stop (30) in end cover (65).
a) Place large spring (29) and small spring (28) in end cover (65).
4. Place washers 2x (80) on screws 2x (81).
a) Place the 2 screws with washers as illustrated in end cover (65), see Exploded view on page 6.
Make sure that all O-rings stay in place. It must be possible to screw in the 2 screws using a 13
mm socket spanner with very light torque, so that the end cover stays in parallel with flange area
of the housing and only with distance for compressing the O-rings less than 1 mm.
b)
Screw in screw (83) with washer (82) using a 10 mm Hex key until end cover is in place.
Screw in remaining six screws (81) with washers (80) using a 13 mm socket spanner, 25 ±
5 N·m [221 ± 44 in·lbf] or 80 ± 10 N·m [708 ± 89 in·lbf] for the 10 mm Hex key.
Place or screw in the plastic plugs after testing or if storage is needed between assembly and testing.
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Service Manual
OSQA/OSQB
Testing
This section describes minimum tests needed, when the OSQ steering valve has been disassembled and
reassembled.
OSQ system
Set-up for testing
Use universal hydraulic work bench with pump capacity: 140 l/min and up to 240 bar pressure for relief
valve setting and steering test.
If the recommended pump flow is not available, then take the characteristic of pilot relief valve into
consideration. Reference OSPB/C/F/D/L LS Steering Units, OLS Priority Valves, OSQ Flow Amplifiers TechnicalInformation, BC00000009, the HP/Qp characteristic in the OSQ chapter, under Technical data.
The hydraulic oil must be with a viscosity of 21 cSt. at 50° and with maximum degree of contamination
according to ISO 4406: 21 / 19 / 16.
1. Connect double rod cylinder to CL and CR ports of OSQ.
2. Connect pilot steering unit OSPBX LS to OSQ: L to L, R to R, P to P, T to T, LS to LS.
3. Connect HT and EF port of OSQ to tank of pump station.
4. With LS pump in pump station: connect LS of OSQ-OSP to LS of pump.
5. Connect pressure gages to all ports of OSQ.
6. Connect steering column and steering wheel to the input shaft of the OSPBX steering unit.
T pressure should not exceed approximately 5 bar. Maximum allowed T pressure is 15 bar. Pump supply
circuit must be adjusted not to exceed 240 bar P-T.
Steering test using steering unit type OSPBX LS
During the testing the following must not occur: motor effect, disturbing vibrations, noise, sticking or
other irregularities.
1. Start the pump.
2. Let the supplied oil flow through the OSQ for a few minutes.
3. Operate the steering wheel by approximately 10 rpm in a smooth manner from end stroke to end
The pump flow should be approximately 40 l/min and pump pressure control should be
approximately 70 bar.
a) At the same time, rotate the steering wheel a few times in both directions to bleed air from the
unit and the system.
stroke of the steering cylinder for at least 5 cycles.
a) Make sure pressure P-T, 70 bar can be achieved, when steering against end stroke.
If this is not possible, the adjusting screw of the pilot relief valve (see item 23, Exploded view on
page 6) must be turned clockwise until P-T, 70 bar is achievable.
4. Verify the steering cylinder does not move, when steering wheel is untouched.
The number of turns on steering wheel must match the following calculation:
i approximately or equal to V/Vvs where V is stroke volume of steering cylinder, ccm Vvs equals OSQ
steering system displacement, ccm/rev
V, stroke volume if cylinder in test rig: 4000 ccm
Vvs, steering system displacement with OSQ 5 and OSPBX 200 LS: 1000 ccm/rev
Greater than i, approximately or equal to 4000/1000, equal to 4 turns lock to lock
The pump flow is adjusted to approximately 140 l/min and pressure to maximum 240 bar.
The steering wheel is actuated until the steering cylinder reaches one of its end strokes and the steering
wheel is actuated in this cylinder position with steering torque 20 ± 5 Nm.
The pilot relief valve (item 23 of exploded view) is set according to specification: Maximum steering
pressure (P-T), bar, for the code in question.
The setting pressure is the pressure on the HP-port minus the HT-port of OSQ.
Neutral positioning
Manual steering test
After adjusting the pilot relief valve, the steering wheel must be able to go to neutral position by itself no
later than approximately 1 second after the activation of the steering wheel has been stopped.
The steering unit and OSQ are properly in neutral position when the pressure drop (HP-HT of OSQ) is no
higher than 30 bar at pump flow 140 l/min, and there must be no movement of the steering cylinder.
Without pressure on HP and HT ports, the OSPBX and OSQ must be able to steer in a smooth manner to
the right and to the left observed by the cylinder movement.
The number of turns on the steering wheel for moving the steering cylinder from lock to lock, must
increase in comparison to do this test with normal pump supply.
Without pump supply the number of turns must match cylinder volume/displacement of OSPBX.
Cylinder volume: 4000 ccm and OSPBX 200 LS greater than number of turns must
be 4000/200 which is approximately or equal to 20 turns.
2800 East 13th Street
Ames, IA 50010, USA
Phone: +1 515 239 6000
Danfoss
Power Solutions Trading
(Shanghai) Co., Ltd.
Building #22, No. 1000 Jin Hai Rd
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Shanghai, China 201206
Phone: +86 21 3418 5200
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www.daikin-sauer-danfoss.com
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