Service Manual
Flow amplifier
OSQA/OSQB
powersolutions.danfoss.com
Service Manual
OSQA/OSQB
Revision history Table of revisions
Date Changed Rev
July 2016 First edition 0101
2 | © Danfoss | July 2016 HN25D293 | AX00000127en-US0101
Service Manual
OSQA/OSQB
Contents
Introduction
Technical specifications
Disassembly
Assembly
Testing
Safety precautions............................................................................................................................................................................4
Symbols used in this literature.................................................................................................................................................... 4
OSQ versions...................................................................................................................................................................................... 5
Exploded view................................................................................................................................................................................... 6
Parts list................................................................................................................................................................................................6
OSQA and OSQB parts list........................................................................................................................................................6
OSQ spare parts list.................................................................................................................................................................... 8
Tools......................................................................................................................................................................................................8
Dismantling counter pressure valve..........................................................................................................................................9
Removing pressure relief valve ................................................................................................................................................11
Removing end cover at PP-connection................................................................................................................................. 12
Removing end cover at LS-connection..................................................................................................................................13
Unscrew orifices, throttle check valve....................................................................................................................................16
Housing and end cover with accessories..............................................................................................................................16
Spools with accessories............................................................................................................................................................... 17
Dismantling directional spool...................................................................................................................................................17
Priority valve spool number of orifices...................................................................................................................................17
Dismantling priority valve spool.............................................................................................................................................. 18
Dismantling amplifier spool.......................................................................................................................................................19
Shock and suction valves............................................................................................................................................................ 23
Cleaning............................................................................................................................................................................................ 24
Inspection and replacement......................................................................................................................................................24
Lubrication....................................................................................................................................................................................... 24
Assembling shock, suction, and check valve....................................................................................................................... 25
Assembling amplifier spool........................................................................................................................................................26
Assembling priority valve spool............................................................................................................................................... 28
Assembling directional spool....................................................................................................................................................29
Installing orifice and throttle check valve.............................................................................................................................29
Installing shock valves..................................................................................................................................................................30
Assembling pressure relief valve..............................................................................................................................................31
Installing OSQB back pressure valve.......................................................................................................................................32
Installing spools..............................................................................................................................................................................33
Installing PP end cover.................................................................................................................................................................34
Installing LS end cover................................................................................................................................................................. 37
Plastic plugs..................................................................................................................................................................................... 39
Set-up for testing........................................................................................................................................................................... 40
Steering test using steering unit type OSPBX LS................................................................................................................40
Pilot relief valve...............................................................................................................................................................................41
Neutral positioning....................................................................................................................................................................... 41
Manual steering test..................................................................................................................................................................... 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 part Note correct orientation
External hex head Mark orientation for reinstallation
Internal hex head Torque specification
Lubricate with hydraulic fluid Press in - press fit
Inspect for wear or damage Pull out with tool - press fit
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Service Manual
OSQA/OSQB
Introduction
OSQ versions
This service literature is valid for:
•
OSQA: Flow-Amplifier without back pressure valve in HT
•
OSQB: Flow-Amplifier with back pressure valve in HT
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1
12
38
14
15
40
41
39
30
29
28
27
10
5
20
20
49
49.2
47
48
46
45
23
23.2
22.2
22
21
25
13
37.1
37.2
37.5
37.4
37.3
2
26
27
28
29
30
37
57
57
58
58
59
6
9
20.11
20.11
26
36
66
65
70
80
81
82
83
4
3
7
11
160
24
81
80
82
83
kwa1464729220764
Service Manual
OSQA/OSQB
Technical specifications
Exploded view
OSQA and OSQB exploded view
BSP: 40 ± 5 N·m
UNF: 15 ± 3 N·m
Parts list
OSQA and OSQB parts list
Parts list
Part Number per unit Item Tightening torque
Housing 1 1 —
Priorty valve spool 1 2 —
Plug 1 3 10 ± 3 N·m
Throttle/check valve 1 4 10 ± 3 N·m
Compress spring 1 5 —
Throttle/check valve 1 6 10 ± 3 N·m
Plug 1 7
Orifice, LS 1 9 10 ± 3 N·m
Spring stop 1 10 —
Orifice, dynamic 1 11 5 ± 1 N·m
Outer spool amplifier 1 12 —
Compress spring 1 13 —
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OSQA/OSQB
Technical specifications
Parts list (continued)
Part Number per unit Item Tightening torque
Inner spool, amplifier 1 14 —
Compress spring 1 15 —
Shock valve 2 20 —
O-ring Ø24 x 2 mm 2 20.11 —
Valve seat 1 21 20 ± 3 N·m
Pilot cone 1 22 —
Spring 1 22.2 —
Adjusting screw 1 23 —
O-ring Ø9 x 2 mm 1 23.2 —
Plug 1 24 —
Directional spool 1 25 —
Orifice 2 26 5 ± 1 N·m
Spring stop 2 27 —
Compress spring 2 28 —
Compress spring 2 29 —
Spring stop 2 30 —
Orifice 1 36 5 ± 1 N·m
Check valve 1 37 20 ± 3 N·m
Screw 1 37.1 5 ± 1 N·m
Compress spring 1 37.2 —
O-ring Ø10.3 x 2.4 mm 1 37.3 —
Valve seat 1 37.4 —
Ball 1 37.5 —
Pin 2 38 —
Locking ring 2 39 —
Plug 1 40 —
Orifice 1 41 5 ± 1 N·m
Compress spring, OSQB only 1 45 —
Piston, OSQB only 1 46 —
Compress spring, OSQB only 1 47 —
Ball, OSQB only 1 48 —
Plug, OSQB only 1 49 25 ± 3 N·m
O-ring Ø23.3 x 2.4 mm, OSQB only 1 49.2 —
O-ring Ø35 x 2 mm 4 57 —
O-ring Ø40 x 2 mm 4 58 —
O-ring Ø10 x 2 mm 2 59 —
Cover 1 65 —
Cover 1 66 —
Model/code label 1 70 —
Spring washer 16 80 —
Screw 16 81 25 ± 5/-0 N·m
Spring washer 2 82 —
Screw 2 83 80 ± 10 N·m
Plug with O-ring 1 160 25 ± 5 N·m
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Service Manual
OSQA/OSQB
Technical specifications
Tools
OSQ spare parts list
Spare parts list
Spare parts Code number Item
Seal kit NBR for OSQ 150F0278
Seal kit Viton for OSQ 11020933 57, 58 , 59
Pilot relief valve kit 11011038 21, 22, 22.2, 23, 23.2
Shock and suction valves complete, 140-160 bar 150F0281 20, 20.11
Shock and suction valves complete, 165-185 bar 150F0282 20, 20.11
Shock and suction valves complete, 200-220 bar 150F0286 20, 20.11
Shock and suction valves complete, 215-235 bar 150F0283 20, 20.11
Shock and suction valves complete, 230-250 bar 150F0284 20, 20.11
Shock and suction valves complete, 270-290 bar 150F0285 20, 20.11
20.11, 23.2, 37.3, 49.2, 57, 58 , 59, and
two aluminum washers for pilot relief
valve of OSQ from before week 43,
year 2004
Tools needed for assembly / disassembly
•
Hexagon keys 4, 5, 6, 8, and 10 mm
•
Ratchet for socket spanners
•
Hexagon socket for external hexagon 6, 13, 17, and 19 mm
•
Hexagon socket for internal hexagon 8 and 10 mm
•
Multigrip pliers
•
Ring spanner 13 mm
•
Screwdrivers 3 and 10 mm
•
Steel mandrels 3, 5 and 8 mm
•
Torque wrench for 12 daNm [1060 lbf in]
•
Magnetic rod
•
Hook
These tools are not available from Danfoss.
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Service Manual
OSQA/OSQB
Disassembly
OSQB: OSQ with back pressure valve in HT
Place the unit on a work bench.
Dismantling counter pressure valve
1.
Screw out the plug with O-ring (49) using an 8 mm Hex key.
2. Take out the small spring (47) using a hook.
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Service Manual
OSQA/OSQB
Disassembly
3. Take out ball (48) using a magnetic rod.
4. Take out the piston (46) using a hook.
5. Take out the spring (45) using a hook.
Dismantled counter pressure valve
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OSQA/OSQB
Disassembly
Removing pressure relief valve
1. Remove plug (24) using a 2 mm screw driver.
Some special versions of OSQ have a cover plug (160) assembled on the top of the pilot relief valve. In
such cases, use a 24 mm
socket spanner.
2.
Screw out the adjusting screw (23) using a 6 mm Hex key.
O-ring (23.2) is fitted to the screw (23).
3. Remove the spring (22.2) with cone (22) using a hook or magnet rod.
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Service Manual
OSQA/OSQB
Disassembly
4.
Screw out the seat (21) using a 6 mm socket spanner.
Removing end cover at PP-connection
1.
Unscrew screws (8x81) with spring washer (8x80) using a 13 mm
with spring washer (82) using a 10 mm Hex key.
socket spanner and screw (83)
2. Remove end cover (66).
Spring stop (30) and springs (28, 29 and 13) will follow the end cover.
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OSQA/OSQB
Disassembly
3. Remove stop (27) from directional spool (25).
Removing end cover at LS-connection
1.
Unscrew screws (8x81) with spring washer (8x80) using a 13 mm socket spanner and screw (83)
with spring washer (83) using a 10 mm Hex key.
2. Remove end cover (65).
Spring stops (10 and 30) and springs (28 and 29) will follow the end cover.
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Service Manual
OSQA/OSQB
Disassembly
3. Remove spring stop (27) for directional spool (25).
4. Remove spring (5) for priority spool (2).
5. Remove directional spool (25).
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Disassembly
6. Remove amplifier spool (12).
7. Remove priority valve spool (2).
8. Remove shock valves (2x20) with screwdriver and hexagon key or mandrel.
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Service Manual
OSQA/OSQB
Disassembly
Unscrew orifices, throttle check valve
1.
Unscrew orifice (9) in LS-connection using a 6 mm Hex key.
2.
Unscrew throttle check valve (6) (if present) in PP-connection using a 6 mm Hex key.
3.
Unscrew orifice (36) in housing using a 4 mm Hex key.
Housing and end cover with accessories
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OSQA/OSQB
Disassembly
Spools with accessories
Dismantling directional spool
Use a mandrel for holding the spool, unscrew orifice (26) using a 4 mm Hex key.
Dismantled directional spool (25) and orifice (26)
Priority valve spool number of orifices
Depending on versions this spool has none, 1, or 2 orifices:
•
OSQ static with external PP: the priority valve spool has no orifice
•
OSQ static with internal PP: the priority valve spool has throttle/check valve (4)
•
OSQ dynamic with external PP: the priority valve spool has plug (3) and orifice, dynamic (11)
•
OSQ dynamic with internal PP: the priority valve spool has throttle/check valve (4) and orifice,
dynamic (11)
As shown in Dismantling priority valve spool on page 18
‒
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Service Manual
OSQA/OSQB
Disassembly
Dismantling priority valve spool
1.
Unscrew throttle/check valve (4) using a 8 mm Hex key and multigrip pliers.
2.
Unscrew orifice, dynamic (11) using a 4 mm
Dismantled priority valve spool (25) with throttle/check valve (4) and orifice, dynamic (11)
Hex key and multigrip pliers.
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OSQA/OSQB
Disassembly
Dismantling amplifier spool
1.
Be careful not to damage the locking ring.
Carefully remove, from the amplifier spool (12), the locking ring (39) from the recess using a 3 mm
screwdriver.
a) Carefully guide the locking ring (39) back.
2.
Be careful not to damage the locking ring.
Carefully take the other locking ring (39) from the recess and guide it back using a 3 mm screwdriver.
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Service Manual
OSQA/OSQB
Disassembly
a) Press out pin (38) using a 3 mm screwdriver or mandrel.
b) Take out the plug (40).
c) Take out the spring (15).
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OSQA/OSQB
Disassembly
d) Take out the other pin (38) using a 3 mm screwdriver or mandrel.
e) Take out the inner spool (14).
3.
Be careful not to damage the spool surface.
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Service Manual
OSQA/OSQB
Disassembly
Unscrew check valve (37) using a 13 mm socket spanner and a mandrel in the pin hole.
4.
Unscrew orifice (41) from plug (40) using a 4 mm Hex key and a mandrel in the pin hole.
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OSQA/OSQB
Disassembly
5.
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)
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Service Manual
OSQA/OSQB
Disassembly
Cleaning
Inspection and replacement
Lubrication
Using low aromatic kerosene, clean all parts carefully.
•
Replace all seals and washers.
•
Check all parts carefully and make any replacements as is necessary.
Before assembling, lubricate all parts with hydraulic oil.
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Service Manual
OSQA/OSQB
Assembly
Assembling shock, suction, and check valve
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.
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Assembly
a) Push locking ring (39) into position.
b) Place locking ring into the recess with end facing away from pin holes.
3. Place spring (15) on end of the inner spool (14).
a) Place plug (40).
b) Place pin (38) through outer spool (12) and plug (40).
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Service Manual
OSQA/OSQB
Assembly
4. Push locking ring (39) into position.
a) Place locking ring into the recess with ends facing away from pin holes.
Assembling priority valve spool
The priority valve spool has throttle/check valve (4) and orifice, dynamic (11).
1.
Screw in orifice, dynamic (11) using a 4 mm
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Hex key and a multigrip pliers, 5 ± 1 N·m.
Service Manual
OSQA/OSQB
Assembly
Assembling directional spool
2.
Screw in throttle/check valve (4) using a 8 mm Hex key and a multigrip pliers, 10 ± 0.3 Nm.
Screw in orifices, 2x (26) in directional spool (25) using a 4 mm Hex key and mandrel for holding
the spool, 5 ± 1 N·m [45 ± 10 lbf·in].
Installing orifice and throttle check valve
1.
Screw orifice (36) in housing using a 4 mm Hex key, 5 ± 1 N·m [45 ± 10 lbf·in].
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Service Manual
OSQA/OSQB
Assembly
2.
Screw orifice (9) in LS-connection using a 6 mm Hex key, 10 ± 3 N·m [89 ± 27 lbf·in].
Installing shock valves
3.
Screw throttle check valve (6), if present in PP-connection using an 8 mm
[89 ± 27 lbf·in].
Flow amplifiers with internal PP, plugs for PP port:
1/4 BSP female in PP-connection; Fit washer and plug; Tightening torque: 40 ± 5 N·m [354 ± 44
•
lbf·in].
7/16 – 20 UNF in PP-connection; Fit O-ring and plug; Tightening torque: 15 ± 3 N·m [133 ± 27
•
lbf·in].
Guide shock valves, 2x (20) with O-rings (2x 20.11) in and then secure it by hand.
Hex key, 10 ± 3 N·m
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OSQA/OSQB
Assembly
Assembling pressure relief valve
1.
2. Place in the spring with cone (22).
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.
a) Insert plastic protection plug (24).
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Service Manual
OSQA/OSQB
Assembly
Installing OSQB back pressure valve
Fit spring (45) in position on piston (46) with Vaseline.
1. Place in assembled piston and spring.
2. Place in ball (48) in the piston (46).
3. Place O-ring (49.2) on plug (49).
a) Fit spring (47) in plug (49) with Vaseline.
b)
Screw in assembled plug and spring using an 8 mm Hex key, 25 ± 3 N·m [221 ± 27 lbf·in].
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OSQA/OSQB
Assembly
Installing spools
1.
Spring control must be placed in correct position against LS-connection.
Guide priority valve spool (2) into place.
2. Place spring (5) on priority valve spool (2)
3.
The orifice must be placed in correct position against LS-connection.
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Service Manual
OSQA/OSQB
Assembly
Guide amplifier spool (12) into place.
4. Guide directional spool (25) into place.
Installing PP end cover
1. Place spring stop (27) on the directional spool (25).
2.
The spring must be fitted at the PP-connection.
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Assembly
Place spring (13) with Vaseline in amplifier spool (12).
3. Place O-rings, 2x (57), 2x (58) and 2x (59) and spring stop (30) in end cover (66).
a) Place large spring (29) and small spring (28) in end cover (66).
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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.
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OSQA/OSQB
Assembly
Installing LS end cover
c)
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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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.
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Assembly
Plastic plugs
c)
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.
Plastic plugs placed or screwed into ports
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P
P
LSLS
PP
T
OSPBX LS
CRCL
OSQA
EF
HP HT
T
R
R
L
L
kwa1468255007577
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 Technical
Information, 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.
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OSQA/OSQB
Testing
Pilot relief valve
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.
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Service Manual
OSQA/OSQB
42 | © Danfoss | July 2016 HN25D293 | AX00000127en-US0101
Service Manual
OSQA/OSQB
©
Danfoss | July 2016 HN25D293 | AX00000127en-US0101 | 43
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