Danfoss OSPU User guide
Technical Information
Steering Unit
OSPU
powersolutions.danfoss.com
Technical Information
OSPU Steering Unit
Revision history Table of revisions
Date Changed Rev
March 2016 Updated to Engineering Tomorrow design 0202
May 2014 Converted to Danfoss layout - DITA CMS BA
Aug 2013 First edition AA
2 | © Danfoss | March 2016 L1313806 | BC00000222en-US0202
Technical Information
OSPU Steering Unit
Contents
A wide range of Steering Components
A wide range of Steering Components....................................................................................................................................4
Conversion factors........................................................................................................................................................................... 5
Technical literature survey
Survey of literature with technical data on Danfoss Steering Components...............................................................6
OSPU general information............................................................................................................................................................ 6
Function
OSPU steering unit...........................................................................................................................................................................7
Function
Function, OSPU LS............................................................................................................................................................................8
Neutral position................................................................................................................................................................................ 8
Steering with normal pump supply...........................................................................................................................................9
Emergency steering: Failing pump supply..............................................................................................................................9
Versions
OSPU LS............................................................................................................................................................................................. 10
Load sensing dynamic............................................................................................................................................................ 10
Non-reaction.............................................................................................................................................................................. 10
Amplification, linear.................................................................................................................................................................10
Amplification, progressive.................................................................................................................................................... 10
Technical data
Displacement, amplification, flow and pressure: OSPU LS ............................................................................................12
A minimum standby pressure..............................................................................................................................................12
Amplification characteristics .....................................................................................................................................................13
Emergency steering: Pressure capability ..............................................................................................................................13
Valve functions in OSPU LS steering units............................................................................................................................14
Pilot pressure relief valve; (P - T, Qp) characteristic...........................................................................................................15
Shock valves.....................................................................................................................................................................................15
Suction valves..................................................................................................................................................................................15
Check valve in P..............................................................................................................................................................................16
Check valve function in LS..........................................................................................................................................................16
Port thread versions for OSPU LS............................................................................................................................................. 17
Dimensions
Dimension.........................................................................................................................................................................................19
Order specifications and weights
Order specifications...................................................................................................................................................................... 20
Weights..............................................................................................................................................................................................20
Code numbers for catalog versions with specifications
Specify your OSPU according to the destinations as in the example underneath the empty scheme:.........21
Code numbers........................................................................................................................................................................... 21
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Technical Information
OSPU Steering Unit
A wide range of Steering Components
A wide range of Steering Components
Danfoss is one of the largest producers in the world of steering components for hydrostatic steering
systems on off-road vehicles. Danfoss offers steering solutions both at component and system levels. Our
product range makes it possible to cover applications of all types - ranging from ordinary 2-wheel
steering (also known as Ackermann steering) to articulated steering, automatic steering (e.g. by sensor)
and remote controlled steering via satellite. We can offer more than 1,800 different steering units and 250
different priority valves categorized in types, variants and sizes.
For hydrostatic steering systems Danfoss offers:
•
Mini steering units with displacements from 32 to 100 cm3/rev [1.95 to 6.10 in3/rev], flow up to 20
l/min [5.28 US gal/min], steering pressure up to 140 bar [2030 psi].
•
Steering units with displacements from 40 to 1200 cm3/rev [2.44 to 73.2 in3/rev], flow up to 100 l/min
[26.4 US gaL/min, steering pressure up to 240 bar [3481 psi].
•
Priority valves for rated flows at 40, 80, 120, 160 and 320 l/min [10.6, 21.1, 31.7, 42.3 and 84.5 US gal/
min], pressure up to 350 bar [5076 psi].
•
Pilot operated flow-amplifiers with amplification factors of 4, 5, 8, 10 or 20 for rated oil flows of 240
and 400 l/min [63.4 and 105.7 US gal/min], steering pressure up to 210 bar [3045 psi].
•
Pilot operated steering valve with steering flow up to 100 l/min [26.4 US gal/min], steering pressure
up to 250 bar [3625 psi] and with integrated priority valve for pump flow up to 120 l/min [31.7 US gal/
min].
For electrohydraulic steering systems Danfoss offers:
•
Pilot operated steering valves (pilot operated by hydrostatic steering unit or by electrical signal) with
steering flows up to 100 l/min [26.4 US gal/min], steering pressure up to 250 bar [3625 psi].
•
Steering units with integrated electrical operated steering valve with steering flow up to 50 l/min
[13.2 US gal/min], steering pressure up to 210 bar [3045 psi].
4 | © Danfoss | March 2016 L1313806 | BC00000222en-US0202
Technical Information
OSPU Steering Unit
A wide range of Steering Components
Characteristic features for steering units:
•
Low steering torque: From 0.5 N•m to 3 N•m in normal steering situations
•
Low noise level
•
Low pressure drop
•
Many types available: Open center Non-reaction, Open center Reaction, Power Beyond, Closed center
Non-reaction, Load Sensing, Load Sensing Reaction
•
One or more built-in valve functions: relief valve, shock valves, suction valves, non-return valve in Pline and in LS-line
•
Optional port connections (according to ISO, SAE or DIN standards)
Characteristic features for electrohydraulic steering systems with OSPE and EHPS:
•
Possibility of GPS, row sensor, variable steering ratio and joystick steering
•
The possibility of manual steering even on very heavy vehicles
•
EHPS: High steering pressure requiring smaller cylinders and flow
•
EHPS: Low pilot pressure and flow giving extremely low noise in the cabin
•
EHPS: Can be combined with Danfoss PVG 32 proportional valve
Conversion factors
1 N•m = [8.851 lbf•in] 1 l = [0.264 US gal]
1 N = [0.2248 lbf] 1 bar = [14.5 psi]
1 mm = [0.0394 in] °F = [1.8°C + 32]
1 cm3 = [0.061 in3]
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Technical Information
OSPU Steering Unit
Technical literature survey
Survey of literature with technical data on Danfoss Steering Components
Detailed data on all Danfoss steering components and accessories can be found in our steering
component catalogues, which is divided in to the following individual sub catalogues:
General information Steering components
Technical data on mini steering units OSPM
Technical data on open center, and closed center steering units OSPB, OSPC, and OSPD
Technical data on load sensing steering units, priority valves and flow
amplifiers
Technical data on hydraulic and electrohydraulic pilot operated steering
valves, electrical actuation modules and appropriate steering units.
Technical data on combined steering unit/electrohydraulic steering valves
and steering wheel sensors
Technical data on load sensing steering unit with amplification OSPU
For technical information on individual variants, please contact the Danfoss Sales Organization.
OSPU general information
OSPU is a flow amplifying, load sensing steering unit, available with amplification factors 2, 3, or 4. OSPU
is a cost-attractive dual displacement steering unit alternative for heavier applications needing reduced
displacement for emergency (manual) steering, such as tractors, backhoe loaders, telehandlers, and
combines.
The OSPU total displacement ranges from 120-500 cc in normal steer mode (amplified). In emergency
steer mode the displacement ranges from 60-125 cc/rev. The standard OSPU has fully linear flow
characteristic (flow versus rpm).
OSPU is also available in a version with continuous progressive amplification factor. This feature will make
a simple “Fast Steer” steering system possible: it enables higher ratio steering flow at higher rpm
meaning less turns lock-lock at higher steering speed. This feature is especially attractive on backhoe
loaders and small wheel loaders.
OSPB, OSPC, OSPF, OSPD, OSPL,
OSPBX, OSPLX, OVPL, OLS and OSQ
EHPS, EHPS w. OLS 320, PVE for EHPS
and OSPCX
OSPE
SASA
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3 6 9 7 8
P301 477
11 12 13 14 15 16
Technical Information
OSPU Steering Unit
Function
OSPU steering unit
The OSPU includes the following main components:
Designation of OSPU elements
Item Description
3 Torque compensator valve
6 P-check valve
7 Spool/sleeve set
8 Gear set
9 LS copy valve
11 Housing
12 Neutral spring package
13 Cross pin
14 Cardan shaft
15 Distributor plate
16 End cover with screws
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Danfoss | March 2016 L1313806 | BC00000222en-US0202 | 7
A
5
A
4
A
3
A
2
A
1
A
u
A
d
A
1-5,d,u
P
T
LS
L R
P301 479
2
1
3
4
5
6
8
9
7
10
P301 480
T
LS
L R
P
2
1
3
4
5
6
7
8
10
9
Technical Information
OSPU Steering Unit
Function
Function, OSPU LS
Designation of OSPU elements
Item Description
1 Shock valves
2 Suction valves
3 Torque compensator valve
4 Emergency steering check valve
5 Pilot pressure relief valve
6 P-check valve
7 Spool/sleeve set: including bleeds, A1-A5, Au and Ad
8 Gear set
9 LS copy valve
10 Priority valve, dynamic type
OSPU Danfoss symbols
OSPU ISO-symbols
The OSPU is a Load Sensing Dynamic steering unit type with built in amplification function in the spool/
sleeve set (7).
The main circuit is identical to other OSP LS steering units like e.g. OSPC: Bleeds of spool/sleeve set (7):
A1-A5 and Ad plus gear set (8).
Additionally the OSPU includes an amplification circuit containing the Au bleed in spool/sleeve/set (7)
and a torque compensator valve (3).
Furthermore the OSPU contains a LS copy valve (9). This valve is needed to be able to use dynamic
priority valve.
Neutral position
The drain bleed Ad of spool/sleeve set (7) is open to tank. All other bleeds, A1-A5 and Au are closed.
When the pump runs, the dynamic flow from the LS line of the priority valve (10) will stream across the LS
copy valve (9) to tank.
8 | © Danfoss | March 2016 L1313806 | BC00000222en-US0202
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