Technical Information

Steering
General, Steering Components

www.danfoss.com

Technical Information
General, Steering Components

Revision history

2 | © Danfoss | March 2021

Table of revisions
Date

ChangedRev

March 2021

Removed discontinued products, set revision number to match online catalog.

0701

Changed document number from 'BC00000096' and '520L0468' to 'BC152886484183'

XX

December 2019 Added EHi steering valve, various data changes including 'Oil temperature' in 'Technicaldata common' section

0501

July 2017

0401

Updated literature number

September 2015 Drawings updated

0400

September 2014 Mistakes corrected

DA

July 2014

CA

Changed to Danfoss layout

December 2009 Steering column deleted

BA

October 2002

AA

First version

BC152886484183en-000701

Technical Information
General, Steering Components
Contents
A wide range of steering components
Conversion factors........................................................................................................................................................................... 7
Survey of literature on Danfoss steering components....................................................................................................... 7
Steering concepts
Hydrostatic steering........................................................................................................................................................................ 8
Steering units OSPM/OSPB/OSPC/OSPF/OSPD/OSPU/OSPL...................................................................................... 8
Flow-Amplifiers OSQA/OSQB ................................................................................................................................................ 9Electrohydraulic steering system................................................................................................................................................9
Electrohydraulic steering......................................................................................................................................................... 9Steering components, general
Steering Units: OSPM, OSPB, OSPC, OSPF, and OSPL........................................................................................................10
Steering unit with 2 rotary meters: OSPD............................................................................................................................. 11
Steering unit with amplifier valve: OSPU.............................................................................................................................. 12
Priority valves: OLSA and OLS....................................................................................................................................................13
Flow-Amplifiers: OSQA and OSQB........................................................................................................................................... 14
Steering valve EHPS...................................................................................................................................................................... 15
OSPE steering valve.......................................................................................................................................................................17
OSPE exploded view and parts list..................................................................................................................................... 18
Steering components, product overview
Variant explanations..................................................................................................................................................................... 19
Steering components, main data and features
OSPM mini steering units............................................................................................................................................................21
The OSPM mini-steering unit is available in three versions:..................................................................................... 21
Main data of OSPM...................................................................................................................................................................21
Features of OSPM:.................................................................................................................................................................... 21
OSPB, OSPC, OSPD open center steering units...................................................................................................................21
OSPB ON............................................................................................................................................................................................21
Main data of OSPB ON:........................................................................................................................................................... 22
OSPC ON/OR.................................................................................................................................................................................... 22
Main data of OSPC ON:........................................................................................................................................................... 22
Main data of OSPC OR:............................................................................................................................................................22
Features of OSPB and OSPC Open center steering units:.......................................................................................... 22
OSPD ON/OR....................................................................................................................................................................................23
Main data of OSPD ON:...........................................................................................................................................................23
Main data of OSPD OR............................................................................................................................................................ 23
Features of OSPD open center steering units:............................................................................................................... 23
OSPB closed center steering units OSPB CN........................................................................................................................ 23
Main data of OSPB CN:............................................................................................................................................................23
OSPB,OSPC, OSPF, OSPD, OSPU, OSPL, load sensing steering units........................................................................... 24
OSPB LS and OSPC LS/LSR.......................................................................................................................................................... 24
The OSPB and OSPC Load Sensing steering unit is available in three versions:................................................ 24
Main data of OSPB LS and OSPC LS:...................................................................................................................................24
Main data of OSPC LSR:.......................................................................................................................................................... 24
Features of OSPB and OSPC load sensing steering units:.......................................................................................... 24
OSPF LS.............................................................................................................................................................................................. 24
Main data of OSPF LS: .............................................................................................................................................................25
Features of OSPF load sensing steering units:............................................................................................................... 25
OSPD LS/LSR.................................................................................................................................................................................... 25
Main data of OSPD LS:.............................................................................................................................................................25
Features of OSPD load sensing steering units:.............................................................................................................. 25
Main data of OSPD LSR:.......................................................................................................................................................... 25
OSPU LS............................................................................................................................................................................................. 26
Main data of OSPU LS:.............................................................................................................................................................26
Features of OSPU load sensing steering units:.............................................................................................................. 26
OSPL LS.............................................................................................................................................................................................. 26
The OSPL load sensing steering unit is available in two versions:..........................................................................26
Main data of OSPL LS:..............................................................................................................................................................26© Danfoss | March 2021

BC152886484183en-000701 | 3

Technical Information
General, Steering Components
Contents
Features of OSPL load sensing steering units:............................................................................................................... 27
OLSA/OLS priority valves.............................................................................................................................................................27
The OLSA and OLS priority valves are available in two versions:............................................................................ 27
Main data of OLSA:...................................................................................................................................................................27
Main data of OLS:......................................................................................................................................................................27
Main data of OLSP:................................................................................................................................................................... 28
Features of OLSA and OLS priority valves:.......................................................................................................................28
OSQ Flow Amplifier....................................................................................................................................................................... 28
The OSQ is available in two versions:................................................................................................................................ 28
Main data of OSQ:.....................................................................................................................................................................28
Features of OSQ flow-amplifier:.......................................................................................................................................... 28
Pilot steering units: OSPBX, OSPLX, OSPCX load sensing steering units................................................................... 29
The “X LS” steering units are available in two versions:..............................................................................................29
Main data of the “X LS” steering units:..............................................................................................................................29
EHPS pilot operated steering valves....................................................................................................................................... 29
EHPS type 0, hydrostatic steering system........................................................................................................................29
EHPS type 1, hydrostatic and electrohydraulic steering system............................................................................. 30
EHPS type 2, hydrostatic and electrohydraulic steering system............................................................................. 30
Main data of EHPS:.............................................................................................................................................................. 30
Features of EHPS:.................................................................................................................................................................31
Pilot steering Unit OSPCX CN for EHPS.................................................................................................................................. 31
Main data of the OSPC CN steering units:........................................................................................................................31
OSPE steering valve.......................................................................................................................................................................31
Main data of OSPE.................................................................................................................................................................... 31
Features of OSPE.......................................................................................................................................................................32
EHi steering valve...........................................................................................................................................................................32
Main data of EHi........................................................................................................................................................................ 32
Features of EHi...........................................................................................................................................................................32
OVPL and OVR valve blocks........................................................................................................................................................33
Main data of OVPL.................................................................................................................................................................... 33
Features of OVPL valve block............................................................................................................................................... 33
OVR angular block....................................................................................................................................................................33
Hydrostatic steering systems
Open center steering system.....................................................................................................................................................34
Load sensing steering systems................................................................................................................................................. 34
Features of load sensing static steering systems with Danfoss LS static steering units.................................35
Features of load sensing dynamic steering systems with Danfoss LS dynamic steering units....................36
Features of load sensing dynamic steering systems with Danfoss OSPF LS steering units.......................... 37
Choice of steering concept and components
Choice of steering concept and components..................................................................................................................... 38
Legislation of steering systems.................................................................................................................................................38
General Information
Technical data common.............................................................................................................................................................. 39
Manual steering pressure............................................................................................................................................................39
Demands on steering columns............................................................................................................................................40
Steering components, main data and features............................................................................................................. 41
Calculation of steering systems................................................................................................................................................ 41
Ackermann steering................................................................................................................................................................ 41
Cylinder........................................................................................................................................................................................ 42
Calculation example of steering cylinder ....................................................................................................................... 43
Calculation example of steering unit................................................................................................................................ 44
Calculation example of pump..............................................................................................................................................44
Steering wheel revolutions and steering speed............................................................................................................44
Calculation of LS steering system with working hydraulics......................................................................................44
Calculation of steering system with flow-amplifier OSQA/OSQB........................................................................... 45
Calculation of steering system for articulated vehicle................................................................................................45
Articulated vehicle................................................................................................................................................................... 46
Complete form.......................................................................................................................................................................... 46
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Technical Information
General, Steering Components
Contents
Pump for flow-amplifiers OSQA/OSQB ............................................................................................................................47
Oil types.............................................................................................................................................................................................47
Particle content, degree of contamination and filtering................................................................................................. 48
Installation........................................................................................................................................................................................ 48
Tightening torques........................................................................................................................................................................49
Starting up and running in......................................................................................................................................................... 49
Maintenance.................................................................................................................................................................................... 50
Information on labels................................................................................................................................................................... 51
Examples of steering systems....................................................................................................................................................51
OSPC ON ..................................................................................................................................................................................... 51
OSPC OR.......................................................................................................................................................................................52
OSPC LS + OLSA ....................................................................................................................................................................... 52
OSPF + OLS................................................................................................................................................................................. 53
OSPD LS........................................................................................................................................................................................53
OSPU LS........................................................................................................................................................................................54
OSPBX LS and OSQA................................................................................................................................................................55
2 x OSPBX LS and OSQB......................................................................................................................................................... 56
OSPBX LS and OSQA shown with electrically driven pump for emergency steering.amplification
during emergency steering...........................................................................................................................................57
EHPS - type 1 steering valve with PVG 32, OSPCX pilot steering unit and PVRES joystick.............................58
EHPS - type 2 steering valve with control module PVED, OSPCX pilot steering unit and joystick..............59
OSPE in system with variable pump and GPS steering...............................................................................................60
Load sensing steering system and load sensing working hydraulics with common oil supply froma fixed displacement pump.......................................................................................................................................... 61© Danfoss | March 2021

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Technical Information
General, Steering Components
A wide range of steering components

Danfoss is one of the largest producers in the world of steering components for hydrostatic steeringsystems 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 (for example, 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.
Danfoss offers:
For hydrostatic steering systems:
Product type

Displacement

Mini steering units

32 – 100 cm3/rev

Rated Flow

Steering Pressure[1.95 – 6.10 in3/rev]

max. 20 l/min[5.28 US gal/min]max. 150 bar[2180 psi]

Steering units

40 – 1200 cm3/rev[2.44 to 73.2 in3/rev]

max. 100 l/min[26.4 US gal/min]max. 240 bar[3481 psi]

Priority valves–40, 80, 120, 160, 320 l/min[10.6, 21.1, 31.7, 42.3, 84.5
US gal/min]max. 350 bar[5076 psi]–
Pilot operated flowamplifiers (factors: 4, 5, 8,
or 10)
Pilot operated steering
valves–

240 and 400 l/min [63.4 and max. 240 bar
105.7 US gal/min][3480 psi]
max. 100 l/min[26.4 US gal/min]max. 250 bar[3625 psi]

For electrohydraulic steering systems

6 | © Danfoss | March 2021

Product type

Displacement

Rated flow

Steering pressure

Pilot operated steering
valves-

100 l/min [26.4 US gal/min]

250 bar [3625 psi]

Integrated electricaloperated steering valve

100 - 500 cm3/rev[6.10 - 30.51 in3]

50 l/min [13.2 US gal/min]

210 bar [3045 psi]Electrical operated
steering valve-

70 l/min [18.5 US gal/min]

210 bar [3045 psi]

BC152886484183en-000701

Technical Information
General, Steering Components
A wide range of steering components
Characteristic features for steering units:

•
•
•
•
•
•

Low steering torque: from 0.5 to 3 N•m in normal steering situations
Low noise levelLow 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 LS-line
Optional port connections according to ISO, SAE or DIN standards

Characteristics for EH steering systems with OSPE, EHPS, and EHi:•••

Possibility of GPS, row sensor, variable steering ratio and joystick steering
Possibility of manual steering even on very heavy vehicles
EHPS:‒ High steering pressure requiring smaller cylinders and flow

‒ Low pilot pressure and flow giving extremely low noise in the cabin‒ 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]

Survey of literature on Danfoss steering components
Detailed data on all Danfoss steering components and accessories can be found in our steering
component catalogs, which is divided in to the following individual sub catalogs:
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

OSPB, OSPC, OSPF, OSPD, OSPL, OSPBX, OSPLX, OVPL,OLS and OSQ

Technical data on load sensing steering unit withamplification

OSPU

Technical data on hydraulic and EH pilot operated
steering valves, electrical actuation modules andappropriate steering units.

EHPS, EHPS w. OLS 320, PVE for EHPS and OSPCXTechnical data on combined steering unit/EH steering
valves and steering wheel sensors

OSPE

Technical data on electrohydraulic steering valves

EHi

Technical data on steering wheel sensors

SASA

For technical information on individual variants, please contact the Danfoss Sales Organization.

© Danfoss | March 2021

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Technical Information
General, Steering Components
Steering concepts
Hydrostatic steering
Danfoss steering components are used in vehicles where the driver has to control high steering forces,
reliably, comfortably and with maximum safety.
Steering units OSPM/OSPB/OSPC/OSPF/OSPD/OSPU/OSPLThe operation of Danfoss steering units OSP- is hydrostatic. That is to say, there is no mechanicalconnection between the steering column and the steered wheels.
Instead there are hydraulic pipes and hoses between steering unit and steering cylinder(s). When thesteering wheel is turned, the steering unit meters out an oil volume proportional to the rate of rotation of
the steering wheel. This volume is directed to the appropriate side of the steering cylinder, while
simultaneously the displaced oil is directed to tank.
In open center systems the steering unit is supplied with oil from a separate pump with fixed
displacement.
Open center hydrostatic steering system

In load sensing (LS) systems one pump can supply oil to steering system and to working hydraulics. A
priority valve ensures that steering always has first priority.
Load sensing hydrostatic steering system

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Technical Information
General, Steering Components
Steering concepts
Flow-Amplifiers OSQA/OSQB
In large vehicles and ships the steering units can be used
Load sensing hydrostatic steering system
withDanfoss Flow-amplifiers which amplify the oil flow to thewith flow amplifier
steering cylinders. These systems with steering units and flowamplifiers also include an inbuilt priority valve which ensures that thesteering takes priority.
When the steering wheel is turned, the oil flow is divided in the flowamplifier in such a way as to ensure that the necessary oil flow is led
to the steering system.
The rest of the oil flow is available for the working hydraulics.

Electrohydraulic steering system
Electrohydraulic steering
On loaders, large forklift trucks, dumpers, heavy tractors, combine harvesters, maize harvesters and othersimilar machines there is often need for electrically actuated steering either in the form of a joystick, or
fully automatic.
For this purpose Danfoss offers:
Combined steering unit and electro hydraulic steering valve, OSPE: OSP for normal manual steering
wheel activated steering and E for electro hydraulic steering activated by electrical input signal either
from GPS or vehicle controller or from steering wheel sensor (Danfoss type SASA) for variable steering
ratio. In variable steering mode, the electro hydraulic valve part adds flow to the metered out flow fromthe steering unit part of the OSPE.
Pilot operated steering valve, EHPS: Electro Hydraulic Power Steering:Electrohydraulic steering system
A basic system (type 0) consists of a pilot steering unit as the signal
source and an EHPS valve block which controls oil flow to thesteering cylinders proportional to the pilot flow. The system can beextended to include an electrical actuator so that, as an alternative, it
becomes possible to steer with a joystick (EHPS type 1).
In addition, the valve block can be supplied with built-in microcontroller and safety critical steering software (EHPS type 2). A
steering system with EHPS type 2 means no steering wheel drift andposibility of variable sterring ratio.

© Danfoss | March 2021

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Technical Information
General, Steering Components
Steering components, general
Steering Units: OSPM, OSPB, OSPC, OSPF, and OSPLThe steering unit consists of a rotary valve and a rotary meter.
Via a steering column the steering unit is connected to the steering wheel of the vehicle. When thesteering wheel is turned, oil is directed from the steering system pump via the rotary valve (spool andsleeve) and rotary meter (gear wheel set) to the cylinder ports L or R, depending on the direction of turn.
The rotary meter meters the oil flow to the steering cylinder in proportion to the angular rotation of thesteering wheel. If the oil flow from the steering system pump is too small, the steering unit can function
as a manual pump - assuming the conditions as described in Manual steering pressure on page 39.

10 | © Danfoss | March 2021

1

Check valve

8

Cross pin2

Shock valve

9

Cardan shaft

3

Relief valve

10

Distributor plate

4

Housing with anticavitation valves11

Gear wheel

5

Spool

12

Gear rim

6

Neutral position spring

13

End cover7

SleeveBC152886484183en-000701

Technical Information
General, Steering Components
Steering components, general
Steering unit with 2 rotary meters: OSPD
The basic function of this type is like the main group of Danfoss steering units, except the gearwheel set(rotary meter). OSPD has 2 rotary meters, which are mechanically connected. A shift valve determines
whether only one or both rotary meters are active. In the case of no pump supply only one rotary meter isactive for emergency steering. In normal steering situations both rotary meters are active.
1
2
3

4
5
4
4
5
6

© Danfoss | March 2021

1

Housing with spool/sleeve set and valves

4

Distributor plates

2

Cardan shafts

5

Gear wheel sets

3

Shift valve complete

6

End cover

150-583.12

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Technical Information
General, Steering Components
Steering components, general
Steering unit with amplifier valve: OSPU
The basic function of this type is like the main group of Danfoss steering units, except the rotary valve
and a torque compensator valve. The rotary valve (spool/sleeve set) of OSPU has an amplification
function, which adds flow directly to the cylinder ports in parallel with oil passing through the rotary
meter (gear wheel set). In the case of no pump supply (emergency steering) only the gear wheel set
meters oil to the cylinder ports. The function of the torque compensator valve is to assure constant
amplification.

12 | © Danfoss | March 2021

1

Amplification valve parts

7

Cross pin2

Housing with valve parts

8

Cardan shaft

3

LS copy valve

9

Distributor plate

4

Spool

10

Gear wheel set

5

Neutral position spring11

End cover6

SleeveBC152886484183en-000701

Technical Information
General, Steering Components
Steering components, general
Priority valves: OLSA and OLS
In systems with Danfoss priority valves and load sensing steering units, steering has first priority. Whenthe steering wheel is turned, the oil flow is distributed in the priority valve in such a way that the oil flow
necessary for steering is led to the steering unit through the CF (controlled flow) connection. The
remaining oil flow is available for the working hydraulics through the EF (excess flow) connection.
The distribution is controlled by the LS signal from the steering unit, so that the oil flow to the steering
unit is always determined by the actual steering rate.

1
2
3© Danfoss | March 2021

Plug
Damping orifice (PP)
Spool

4
5
6

Housing
SpringLS-plug with LS-orificeBC152886484183en-000701 | 13

Technical Information
General, Steering Components
Steering components, general
Flow-Amplifiers: OSQA and OSQB
The flow-amplifiers OSQA and OSQB contain a directional valve, an amplification valve, a priority valve, apilot pressure relief valve, shock and suction valves.
In addition OSQB contains a back pressure valve. The flow-amplifier amplifies the oil flow from thesteering unit cylinder ports L or R by an amplification factor of 4, 5, 8, 10 or 20.
The amplified oil flow is directed from the flow-amplifier ports CL or CR to the steering cylinder(s). The
amplified flow is proportional to the rate of the steering wheel rotation. If the oil flow from the pumpfails, the flow-amplifier cuts off the amplification and manual steering through the steering unit ispossible under the same conditions as those mentioned in the section: Manual steering pressure on page
39.
The pressure drop through the flow-amplifier at manual steering is about 5 bar [72.5 psi].

14 | © Danfoss | March 2021

1

Housing

5

Pilot pressure relief valve

2

Shock and suction valves

6

Priority valve

3

Back pressure valve

7

Amplification valve

4

Directional spool

BC152886484183en-000701

Technical Information
General, Steering Components
Steering components, general
Steering valve EHPSThe EHPS is a pilot operated directional valve. Oil from a pilot steering unit or an electrical signal canactuate the steering valve.
Basicly the EHPS valve contains a directional valve, a priority valve, a pilot relief valve, a pilot pressure
control valve, and shock- and suction valves.
An electric actuation module, PVE, can be fitted onto the EHPS valve. In the type 1 system the controller isoperated by an analog signal and the type 2 system the signal is digital with Canbus interface and it
comprises a micro processor with safety critcal steering software.
The pilot for the directional valve in EHPS can be supplied either by the flow from steering unit (cylinder
port L or R), or by the flow from the electric actuation module PVE/PVED.
5 11
1 11 2© Danfoss | March 2021

4

3

9

8

6

2

10

2

7

P301 018

1

Electrical actuation module PVE/PVED

6

Pilot pressure valve for electrical actuating
module2

Housing7

Priority valve

3

Directional spool

8

Cover

4

Shock and suction valve

9

Emergency steering valve

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Technical Information
General, Steering Components
Steering components, general
5

16 | © Danfoss | March 2021

Pilot pressure reduction valve for steering unit

10

Pilot pressure relief valve

11

Shuttle valves

BC152886484183en-000701

Technical Information
General, Steering Components
Steering components, general
OSPE steering valve
OSPE with an electrical programmable module (PVED-CL) the following steering features in electro
hydraulic steer mode/field mode are possible:• GPS-steering

•
•
•
•

Row sensor/ camera steering
Joy stick or mini st. wheel steering
Variable steering ratio
Speed depending steering ratio

The following block diagram shows all input devices possible for the PVED-CL actuator/controller.
Detailed description is to be found in seperate literature, PVED-CL User Manual, please contact Danfoss
Sales Organization.

© Danfoss | March 2021

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Technical Information
General, Steering Components
Steering components, general
OSPE exploded view and parts list

18

9, 10, 11814, 15, 17

16
7
21

13
12

2
22

1

3

5
P301 216

1

Shock valves

12

Control valve for mode select2

Suction valves

13

Pilot reduction valve, 12 bar

3Spool/sleeve set

14

PP damping orifice5

Gear set

15

Priority valve spool

7

Mode select and EH cut off valve

16

Priority valve spring

8

EH directional valve

17

Dynamic orifice9

PVE control unit

18

Pilot pressure relief valve

10

LVDT transducer

21

PVFC valve/LS resolver

11

Solenoid valve bridge

22

Neutral spring package for spool/sleeve

18 | © Danfoss | March 2021

BC152886484183en-000701

Technical Information
General, Steering Components
Steering components, product overview
Type

Variants

Description

Steering units
OSPM

ON, PB,
LSd

Mini steering unit for smaller vehicles

OSPB

ON, CN,LS,

Steering unit with no valve functions

OSPCON, OR,
ORM, LS,
LSd, LSR,
LSRd,
LSRMd

Steering unit with valve functions

OSPF

LSd

Steering unit full drain dynamic load sensing and with valve functions

OSPD

ON, LSd,
LSRd,
LSRMd

Steering unit with 2 displacements and with valve functions

OSPU

LSd

Steering unit with flow amplification and with valve functions

OSPL

LS, LSd

Steering unit for larger vehicles

OSPBX

LS

Pilot steering unit for OSQ static

OSPLX

LS

Pilot steering unit for OSQ static

OSPCX

LSd

Pilot steering unit for OSQ dynamic

OSPCX

CN

Pilot steering unit for EHPS

Priority valves
OLSA

LS, LSd

Priority valve for flanging on steering unit

OLS

LS, LSd

Priority valve for in line use

OLSP

LS, LSd

Priority valve for flanging on gear pumps

Flow-Amplifiers
OSQA

LS

Flow-amplifier

OSQB

LS

Flow-amplifier with back pressure valve

Steering valve
EHPS
type 0LSd

Pilot operated steering valve

Electrohydraulic power steering
EHPS
type 1

LSd

Pilot operated steering valve with electrical actuation module

EHPS
type 2

LSd

Pilot operated steering valve with programmable electrical actuation module

OSPE

LSd,
LSRMd

Combined steering unit/electrohydraulic steering valve

EHi

LS, LSd

Electrohydraulic steering valve for in-line use

Valve blocks
OVPL-

Valve block for OSPLOVR-

Angular block for side ported steering units

Variant explanations•••© Danfoss | March 2021

ON: Open center Non-reaction
LS: Load Sensing, static
OR: Open center Reaction

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Technical Information
General, Steering Components
Steering components, product overview

•
•
•
•
•
•

20 | © Danfoss | March 2021

ORM: Open center Reaction RM-technology
LSd: Load Sensing, dynamic
CN: Closed center Non-reaction
LSR: Load Sensing Reaction, static
PB: Power Beyond LSRd: Load Sensing Reaction, dynamic
LSRMd: Load Sensing Reaction RM-technology, dynamic

BC152886484183en-000701

Technical Information
General, Steering Components
Steering components, main data and features
OSPM mini steering units
For light vehicles such as garden tractors, municipal vehicles, lawn
mowers, small fork lift trucks, etc., Danfoss offers OSPM hydrostatic
steering units.

The OSPM mini-steering unit is available in three versions:•••

Open center Non-reaction (ON)Power Beyond (PB), where surplus oil can be led to working hydraulics.
Load Sensing non-reaction (LS) dynamic

Main data of OSPM

•
•
•
•

Displacement: 32 - 100 cm3/rev [1.95 - 6.10 in3/rev]
Flow, recommended: 3 - 20 l/min [0.79 - 5.28 US gal/min]Maximum steering pressure: 125 bar [1812 psi]
Maximum back pressure (T): 20 bar [290 psi]

Features of OSPM:

•
•
•
•
•

Small dimensions and low weight
Low steering torque 0.5 to 1.5 N•m [4.43 to 13.28 lbf•in]
One or more built-in valve functions: pressure relief, shock in L + R (servo ports Left and Right) and /or non return in P (Pump connection and check valve in LS line)
End ports with integrated fittings (ORFS and check valve in LS line): O-ring face seal or side ports,
male type
Possibility of integrated steering column

OSPB, OSPC, OSPD open center steering units
For small to large vehicles typically tractors, harvesters, fork lifts, contractors machines and special
vehicles, etc., Danfoss offers a wide range of hydrostatic steering units.
For open circuit systems, where a seperate fixed displacement pump is supplying the steering systemwith oil the following types of Danfoss steering units are suitable:• OSPB, OSPC and OSPDOSPB ONThe OSPB Open center steering unit is avaiable in one version:© Danfoss | March 2021

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Technical Information
General, Steering Components
Steering components, main data and features•

Open center Non-reaction (ON)Main data of OSPB ON:• Displacement:50 - 500 cm3/rev [3.05 - 30.5 in3/rev]• Flow, recommended:5 - 70 l/min [1.32 - 18.5 US gal/min]‒ Maximum steering pressure: 210 bar[3045 psi]
‒ Maximum back pressure: 40 bar [580 psi]

OSPC ON/ORThe OSPC Open center steering unit is available in two versions:• Open center Non-reaction (ON)• Open center Reaction (OR)Main data of OSPC ON:

•
•
•
•

Displacement: 40 - 500 cm3/rev [2.44 - 30.51 in3/rev]
Flow, recommended: 4 - 70 l/min [1.06 - 18.49 US gal/min]Maximum steering pressure: 210 bar [3045 psi]
Maximum back pressure: 40 bar [580 psi]

Main data of OSPC OR:•••

Displacement: 40 - 200 cm3/rev [2.44 - 12.21 in3/rev]
Flow, recommended: 4 - 50 l/min [1.06 - 13.21 US gal/min]Maximum steering pressure: 210 bar [3045 psi]

Features of OSPB and OSPC Open center steering units:•••

22 | © Danfoss | March 2021

Low steering torque 0.8 to 3.0 N•m [7.08 to 26.6 lbf•in] in normal steering situations due to low effort
springs and wide control range.
Low noise due to laminar flow conditions throughout profile-grinded passages.
OSPC: one or several built in valve functions: pressure relief, shock in L + R, suction in L + R and / or
non-return in P.

BC152886484183en-000701

Technical Information
General, Steering Components
Steering components, main data and features
OSPD ON/ORThe OSPD Open center steering unit is available in two version:• Open center Non-reaction (ON) version• Open center Reaction (OR) version

Main data of OSPD ON:

•

•
•
•

Displacement :‒ From 60 cm3/rev to max 125 cm3/rev [3.66 to max. 7.63 in3/rev] during manual steering without
pump oil supply and with one rotary meter active.
‒ From 185 cm3/rev up to 440 cm3/rev [11.3 up to 26.9 in3/rev] at full oil supply and with bothrotary meters active.
Flow, recommended: 19 - 70 l/min [5.02 - 18.49 US gal/min]Maximum steering pressure: 210 bar [3045 psi]
Maximum back pressure: 40 bar [580 psi]

Main data of OSPD OR•

Displacement:‒ 60 cm3/rev or 70 cm3/rev [3.66 in3 or 4.27in3/rev] during manual steering‒ From 185 cm3/rev up to 220 cm3/rev [11.28 up to 13.42 in3/rev] at full oil supply•••

Flow recommended: 12 - 50 l/min [3.17 - 13.21 US gal/min]Maxumum steering pressure: 210 bar [3045 psi]
Maximum back pressure: 40 bar [580 psi]

Features of OSPD open center steering units:•

Features like OSPC Open center steering units plus:‒ Possibility of manual steering of heaviest vehicles, without the need for an emergency pump.

OSPB closed center steering units OSPB CN
For constant-pressure systems with variable pump flow Danfoss
offers the steering unit types: OSPB CN
The OSPB closed center steering unit is available in one version:• Closed center Non-reaction (CN)Main data of OSPB CN:••••© Danfoss | March 2021

Displacement: 50 - 400 cm3/rev [3.05 - 24.4 in3/rev]
Flow: 5 - 50 l/min [1.32 - 13.20 US gal/min]Maximum steering pressure: 175 bar [2538 psi]
Maximum back pressure: 40 bar [580 psi]

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Technical Information
General, Steering Components
Steering components, main data and features
OSPB,OSPC, OSPF, OSPD, OSPU, OSPL, load sensing steering units
For small to large vehicles typically tractors, harvesters, fork lifts,
contractors machines and special vehicles, etc., Danfoss also offers awide range of hydrostatic steering units of the Load Sensing (LS)types: OSPB, OSPC, OSPF, OSPD, and OSPU LS steering units are for
Load Sensing systems, where oil is supplied by a pump via a priority
valve or from a pump with variable displacement.

OSPB LS and OSPC LS/LSR
The OSPB and OSPC Load Sensing steering unit is available in three versions:•••

Load Sensing non-reaction (LS) static
Load Sensing non-reaction (LS) dynamic
Load Sensing Reaction (LSR) dynamic (only OSPC)

Main data of OSPB LS and OSPC LS:

•
•
•
•

Displacement: 40 - 400 cm3/rev [2.44 - 24.4 in3/rev]
Flow: 4 - 40 l/min [1.06 - 10.57 US gal/min]Maximum steering pressure: up to 210 bar [3045 psi]
Maximum back pressure: 40 bar [580 psi]

Main data of OSPC LSR:

•
•
•
•

Displacement: 40 - 200 cm3/rev [2.44 - 12.20 in3/rev]
Flow: 4 - 20 l/min [1.06 - 5.28 US gal/min]Maximum steering pressure: 210 bar [3045 psi]
Maximum back pressure: 40 bar [580 psi]

Features of OSPB and OSPC load sensing steering units:•••

Low steering torque 0.8 to 3.0 N•m [ 7.08 to 26.55 lbf•in] in normal steering situations
Low noise
OSPC: one or several built in valve functions: pilot pressure relief, shock in L + R, suction in L + R
and/or non-return in P. OSPC LS/LSR Dynamic: non-return valve in LS-connection.

OSPF LS
The OSPF Load Sensing steering unit is available in one version:• Full drain Load Sensing non-reaction (LS) dynamic

24 | © Danfoss | March 2021

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Technical Information
General, Steering Components
Steering components, main data and features
Main data of OSPF LS:

•
•
•
•

Displacement: 80 - 400 cm3/rev [4.88 - 24.4 in3/rev]
Flow: 8 - 40 l/min [2.11 - 10.57 US gal/min]Maximum steering pressure: 210 bar [3045 psi]
Maximum back pressure: 40 bar [580 psi]

Features of OSPF load sensing steering units:

•
•
•
•

Low steering torque 0.5 to 1.8 N•m [4.43 to 15.93 lbf•in]in normal steering situations
Low noise and wide control range
Higher maximum steering speed, limited only by the capacity of the pump and the pressure setting
One or several built in valve functions: pilot pressure relief, shock in L + R, suction in L + R and / or
non-return in P.

OSPD LS/LSR
The OSPD Load Sensing steering unit is available in two
versions:• Load Sensing non-reaction (LS) dynamic• Load Sensing Reaction (LSR) dynamic

Main data of OSPD LS:

•

•
•
•

Displacement :‒ From 60 cm3/rev to max 125 cm3/rev [3.66 to max. 7.63 in3/rev] during manual steering without
oil supply and with one rotary meter active.
‒ From 185 cm3/rev up to 440 cm3/rev [11.28 up to 26.9 in3/rev] at full oil supply and with bothrotary meters active.
Flow: 19 - 44 l/min [5.02 - 11.62 US gal/min]Maximum steering pressure: 210 bar [3045 psi]
Maximum back pressure: 40 bar [580 psi]

Features of OSPD load sensing steering units:•

Features like OSPC LS plus :‒ Possibility of manual steering of heaviest vehicles, without the need for an emergency pump.

Main data of OSPD LSR:

•

•
•
•

© Danfoss | March 2021

Displacement :‒ From 60 or 70 cm3/rev [3.66 or 4.27 in3/rev] during manual steering‒ From 185 to 220 cm3/rev [11.28 to 13.42 in3/rev] at full oil supply
Flow: 19 - 22 l/min [5.02 - 5.81 US gal/min]Maximu steerring pressure: 210 bar [3045 psi]
Maximum back pressure: 40 bar [580 psi]

BC152886484183en-000701 | 25

Technical Information
General, Steering Components
Steering components, main data and features
OSPU LS
The OSPU Load Sensing steering unit is available in one version:• Load Sensing non-reaction (LS) dynamic with build in amplification
function

Main data of OSPU LS:•

Displacement :‒ From 60 to 125 cm3/rev [3.66 to 7.63 in3/rev] during manual steering without pump oil supply‒ From 120 to 500 cm3/rev [7.32 to 30.51 in3/rev] at normal pump supply. Amplification factors 2, 3•••

or 4 linear of 2 progressive.
Flow: 8 - 50 l/min [2.11 - 13.21 US gal/min]Maximum steering pressure: 210 bar [3045 psi]
Maximum back pressure: 40 bar [580 psi]

Features of OSPU load sensing steering units:•

Features like OSPC LS plus

‒ Possibility of manual steering of heavier vehicles, without the need for an emergency pump
‒ Possibility of “Fast Steer” with progressive amplification

OSPL LS
For larger vehicles typically heavy fork lift trucks, loaders anddumpers, Danfoss also offers a hydrostatic steering units of the Load
Sensing (LS) type optimized for high steering flow: OSPL.

The OSPL load sensing steering unit is available in two versions:••

Load Sensing non-reaction (LS) static
Load Sensing non-reaction (LS) dynamic

Main data of OSPL LS:

•
•
•
•

26 | © Danfoss | March 2021

Displacement : 520 - 1200 cm3/rev [31.8 - 73.2 in3/rev]
Flow: 52 - 100 l/min [13.74 - 26.4 US gal/min]Maximum steering pressure: 240 bar [3480 psi]
Maximum back pressure: 40 bar [580 psi]

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Technical Information
General, Steering Components
Steering components, main data and features
Features of OSPL load sensing steering units:

•
•
•
•

Low steering torque 0.8 to 3.0 N•m [7.08 to 26.6 lbf•in] in normal steering situations
Low noise
Low pressure drop even at high flow
Possibility of built in valve function: pilot pressure relief valve. The OVPL valve block for OSPL contains
shock L + R, suction L + R, non-return in pump line and / or back pressure valve in tank connection.

OLSA/OLS priority valves
For Load Sensing systems, Danfoss offers a wide range of priority
valves:Priority valves for flang mounting to Danfoss LS-Steering units:
OLSA (Except for OSPU and OSPL)
Priority valves for in-line use: OLS

OLSAThe OLSA and OLS priority valves are available in two versions:• Static and• Dynamic

OLS 40/80

Main data of OLSA:• Flow, rated: 40 or 80 l/min [10.57 - 21.1 US gal/min]• Maximum system pressure: 250 bar [3625 psi]

OLS 120Main data of OLS:

• Flow, rated: 40, 80, 120, 160 or 320 l/min [10.57, 21.1, 31.7, 42.3 or
84.5 US gal/min]

OLS 160• Maximum system pressure: 280 bar [4061 psi]
‒ OLS 160: 350 bar [5076 psi] on P and EF port

© Danfoss | March 2021

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Technical Information
General, Steering Components
Steering components, main data and features
Main data of OLSP:• Flow, rated: 80 l/min [21.1 US gal/min]• Maximum system pressure: 250 bar [3625 psi]

OLSP

Features of OLSA and OLS priority valves:• Low noise valves• OLS 160 and OLS 320: available with pilot pressure relief valve

OLS 320OSQ Flow Amplifier
For very heavy vehicles typically very large fork lift trucks, loaders,dumpers and special vehicles weighing one hundred ton or
more,Danfoss offers a flow-amplifier to amplifie the oil from thestering unit: OSQ. The OSQ is based on the load sensing steering
principle.

OSQB

The OSQ is available in two versions:• OSQA for normal fittings connection• OSQB with back pressure valve in tank connection and for flange
type fittings

Main data of OSQ:

•
•
•
•

Amplification factors : 4, 5, 8, or 10
Total displacement of steering system: 640 - 4160 cm3/rev [39 - 254 in3/rev]
Flow: OSQA: 240 l/min [63.4 US gal/min]OSQB: 400 l/min [105.7 US gal/min]Maximum steering pressure: 240 bar [3480 psi]

Features of OSQ flow-amplifier:•••28 | © Danfoss | March 2021

High steering capacity
Low pressure drop even at high flow
Possibility of built in valve functions: pilot pressure relief valve, priority valve, shock and suction
valves in L + R. OSQB also has back pressure valve in tank connection.

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Technical Information
General, Steering Components
Steering components, main data and features
Pilot steering units: OSPBX, OSPLX, OSPCX load sensing steering units
The OSQ flow-amplifiers require special pilot steering units of the
OSPBX LS
type
• OSPBX LS• OSPLX LS or• OSPCX LS
which are all load-sensing steering units whose L- and R- connections
are open to tank in neutral position.

The “X LS” steering units are available in two versions:••OSPBX LS for OSQA and OSQBOSPLX LS for OSQA and OSQB

Main data of the “X LS” steering units:
Displacement OSPBX LS and OSPCX LS 160 - 400 cm3/rev [9.76 - 24.4 in3]
Displacement OSPLX LS 520 - 630 cm3/rev [31.7 - 38.4 in3]
Maximum steering pressure 240 bar [3480 psi]
EHPS pilot operated steering valves
For larger vehicles typically big tractors, heavy fork lift trucks, loadersand dumpers, Danfoss also offers a hydraulic and electro-hydraulicpilot operated steering valve type EHPS.
EHPS systems are available in three versions.

EHPS type 0, hydrostatic steering system
EHPS Type 0 is a purely hydraulic steering system with the EHPS valve acting as a pilot operated
directional valve. A steering unit acts as a pilot unit delivering oil at a low pressure and low flow. The
steering unit needs less displacement as in an ordinary hydrostatic steering system. The displacement
can be optimised for emergency steering.

Joystick

OSP
Q
PVE

EHPS valve

Q

Steering
cylinger
150-566.10© Danfoss | March 2021

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Technical Information
General, Steering Components
Steering components, main data and features
EHPS type 1, hydrostatic and electrohydraulic steering system
This system consists of an EHPS valve (type 0) equipped with anelectrical activation unit (PVE). There are 2 possibi-lities of steering:either hydraulic with the steering wheel or electrical using a signal
from, for example, a joystick. The valve gives highest priority to thesignal from the steering wheel.

Joystick

OSP
Q
Q

EHPS valve

PVE

Steering
cylinger
150-566.10

EHPS type 2, hydrostatic and electrohydraulic steering system
This system consists of an EHPS valve equiped with an electricalactivation unit (PVED), steering wheel sensor and position sensor.
Then it is possible to steer by wire with active hydraulic back up.
The safety system in the integrated microcontroller gives steeringwith an electrical signal a very high level of safety.
The characteristics are variable steering ratio on the steering wheel,
elimination of steering wheel drift and the possibility ofcommunicating with automatic steering.

Steering Wheel Sensor
SASA

Joystick

OSP
Q
PVED CLS

EHPS valve

Vehicle Speed

Q

Steering
cylinger

Position Seorn

CAN bus150-565.12

Main data of EHPS:•••

30 | © Danfoss | March 2021

Flow for steering: up to 100 l/min [26.4 US gal/min]Maximum steering pressure: 250 bar [3625psi]
Maximum pump flow to priority valve in EHPS: 150 l/min [31.6 US gal/min]

BC152886484183en-000701

Technical Information
General, Steering Components
Steering components, main data and features
Features of EHPS:

•
•
•
•
•
•

High steering pressure requiring smaller steering cylinders.
Low pilot pressure up to 30 bar [435 psi] for the pilot steering function giving an extremely low noiselevel in the cab.
With integrated valve functions: pilot pressure relief, priority, shock and suction in L + R and pilotpressure control.
Possibility of emergency steering (manual) in the event of pump failure.
Minimal side acceleration on vehicles with articulated steering.
Micro controller with safety critical software means:‒ No steering wheel drift.

‒ Possibility of variable steering ratio.
‒ Possibility of automatic steering‒ CAN-bus interface.
•

EHPS can be built together with Danfoss proportional valves (PVG 32).

Pilot steering Unit OSPCX CN for EHPSThe EHPS pilot operated steering valve requires a special pilot steering unit, viz:
• OSPCX CN
that is a closed-center steering unit whose L- and R-connections are open to tank in neutral position.
Main data of the OSPC CN steering units:
Displacement: 50-200 cm3/rev [3.05 - 12.20 in3]
Maximum pilot steering pressure: 30 bar [435 psi]
OSPE steering valve
The OSPE Load Sensing Steering Valve is available in 4 version:• Load Sensing non-reaction (LS) dynamic• Load Sensing Reaction (LSRM) dynamic• “D” Load Sensing non-reaction (D-LS) dynamic with double gearset
• “D” Load Sensing Reaction (D-LSRM) dynamic with double gear set

Main data of OSPE

•
•
•
•
•
•

© Danfoss | March 2021

Displacement: 100-500 cm3/rev [6.10 - 30.51 in3]
Flow, steering wheel steering: 10-50 l/min [2.64-13.21 US gal/min]Flow, EH Steering: 12-40 l/min [3.17-10.57 US gal/min]Maximum flow to priority valve in OSPE: 90 l/min [23.78 US gal/min]Maximum steering pressure: 210 bar [3045 psi]
Maximum back pressure: 25 bar [363 psi]

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Technical Information
General, Steering Components
Steering components, main data and features
Features of OSPE

•
•
•
•

Integrated EH valve in hydraulic steering unit
True “safe-state”: Shut-off valve for EH part
Selectable “reaction” - Non-reaction” steering modes
Integrated priority valve

EHi steering valve
EHi is offered in various versions to match the base steering unit on
the vehicle.
EHi is available for:• OC: Open Center steering units• LD: Load Sensing Dynamic steering units• LS: Load Sensing Static steering units• N: Non reaction type steering units• R: Reaction type steering units
EHi is also offered in verssions for pure Steer by Wire usage

Main data of EHi

•
•
•
•
•

Flow, EH Steering: 12-70 l/min [3.17-18.54 US gal/min]Maximum flow to priority valve in EHi: 90 l/min [23.78 US gal/min]Maximum steering pressure: 210 bar [3045 psi]
Maximum P and EF port pressure: 250 bar [3625 psi]
Maximum back pressure: 25 bar [363 psi]

Features of EHi

•
•
•
•

32 | © Danfoss | March 2021

Flexible alternative to Danfoss OSPE, for vehicles where space around steering unit is limited
True “safe-state”: Shut-off valve for EH part
Selectable “reaction” - Non-reaction” steering modes when using Reaction type steering unit
Integrated priority valve

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Technical Information
General, Steering Components
Steering components, main data and featuresOVPL and OVR valve blocks
For the OSPL Load Sensing unit Danfoss offers a flange on valve block: OVPL
Main data of OVPL• Flow: 100 l/min [26.4 US gal/min]• Max. pressure setting: 270 bar [3916 psi] on shock valves

Features of OVPL valve block••

Double service ports (2x L and 2x R) as option
Possibility of built in valve functions: shock and suction in L + R, non-return in pump line, backpressure in tank line.

OVR angular block
The OVR is designed specially for applications where pipes and/or
hoses must run parallel with the steering column axis of the steering
unit, and where space is limited.
The OVR contains no valve functions.
The OVPL and OVR can only be used in connection with steering
units without spot facing around the port connections on the port
surface.

© Danfoss | March 2021

BC152886484183en-000701 | 33

Technical Information
General, Steering Components
Hydrostatic steering systems
Open center steering system
In Open center systems a fixed displacement pumpconstantly supplies oil to the steering circuit separately.
Features of open center steering systems with
Danfoss open center steering units• Immediate reaction of the steered wheels, once thesteering wheel begins to turn.
• High steering comfort maintained throughout
significant changes of steering load and pump oil flow.
• Damping characteristics when system-conditioned
pressure variations occur.
• Simple system build-up with stable steering under all
conditions.

150-568.11

Load sensing steering systems
In Load Sensing steering systems the oil for the steering system is supplied by a pump via a priority valve
or from a pump with variable displacement.
For Load Sensing systems Danfoss offers 3 basic types of steering units:

34 | © Danfoss | March 2021

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Technical Information
General, Steering Components
Hydrostatic steering systems
Features of load sensing static steering systems with Danfoss LS static steering units
OSP LS Static• No flow through the steering unit when not steering:
minimum loss of energy.

150-569.11© Danfoss | March 2021

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Technical Information
General, Steering Components
Hydrostatic steering systems
Features of load sensing dynamic steering systems with Danfoss LS dynamic steering units
OSP LS Dynamic• Constant flow through the unit when not steering,recommended level:• 0.6 – 0.9 l/min [0.16 – 0.24 US gal/min] for standard(low) dynamic LS steering units• 1.0 – 1.3 l/min [0.26 – 0.34 US gal/min] for highdynamic LS steering units, to be used when extreme
response is requested• Dynamic flow causes quick reaction time when startingto steer (no hard spot)• Check valve in P-line and in LS-line of steering unit
avoids kick back at the steering wheel• Steering unit always has the same temperature as theoil in the entire system, therefore no risk of sticking
spool/sleeve set in housing even when starting up
under very cold conditions

150-570.11

36 | © Danfoss | March 2021

BC152886484183en-000701

Technical Information
General, Steering Components
Hydrostatic steering systems
Features of load sensing dynamic steering systems with Danfoss OSPF LS steering units
OSPF LS Dynamic• Constant flow through the unit when not steering,recommended level: 1.1 - 1.5 l/min [0.29 - 0.40 US gal/min]
• Dynamic flow eliminates hard point when starting
steering• No kick back in steer wheel because of check valve in
P- and no connection P-line to LS-line• Steering unit always has the same temperature as theoil.
• OSPF is extremely good in controlling negative
steering forces• Higher max. steering speed, limited only by thecapacity of the pump and the pressure setting

150-571.11© Danfoss | March 2021

BC152886484183en-000701 | 37

Technical Information
General, Steering Components
Choice of steering concept and components
Choice of steering concept and components
The choice of steering concept is determined mainly by vehicle design, performance requirements andrequired operating functions.
When a hydrostatic system is chosen, the next step involves deciding whether the hydraulic steeringsystem is to be:• Open Center steering system• Power Beyond steering system• Closed Center non-Load-Sensing steering system• Load Sensing steering system
The choice will also depend on system cost requirements, hydraulic system energy consumption andsystem complexity.
When a Load Sensing system has been chosen, there are three further possibilities:• Load Sensing Static steering system• Load Sensing Dynamic Steering system• Load Sensing Dynamic steering system based on Danfoss OSPF steering units
The choice here will depend on performance requirements and running-in complexity:• Load Sensing Static steering systems are the simplest Loading Sensing types as regards the initial
setting up of the priority valve spring/orifices combination. Do not recommend Static steeringsystems, only use if customer insists. With “Static” you risk thermal shock, which may harm thesteering unit, kick back and/or hard spot in steering wheel.
• Load Sensing Dynamic steering systems give better steering performance than Static steeringsystems. See Features of load sensing dynamic steering systems with LS dynamic steering units• Load Sensing Dynamic steering systems with OSPF steering units give by far the best steeringcharacteristics. See Features of load sensing dynamic steering systems with OSPF LS steering units. Such asystem can require highly precise setting up of the priority valve spring/orifices combination and it isessential to ensure high “dynamic” flow from the priority valve, min. 1.1 l/min [0.29 US gal/min].
When specifying a steering system, there are two steering unit options, viz. “Reaction” and “Nonreaction”:• With reaction steering units, any external forces that act on the steered wheels result in acorresponding movement of the steering wheel, when the driver is not steering the vehicle• With non-reaction steering units there is no such corresponding movement of the steering wheel,
when the driver is not steering the vehicle
For vehicles with rear-wheel steering and articulated steering, or for vehicles that require a steering unit
displacement >250 cm3/rev [15.25 in3/rev], Danfoss always recommends non-reaction steering units.
Size calculations on steering cylinders, steering units and pumps for steering systems are given in“General information” in the next section.
If a suitable compromise cannot be achieved between minimum necessary displacement determined by
maximum desired number of steering wheel revolutions from lock to lock, and maximum permissible
displacement for building up the steering pressure in emergency situations with pump failure, it ispossible to choose a steering unit with variable displacement: type OSPD or OSPU.
Legislation of steering systems
Please pay attention to country specific legislation for hydraulic/electro-hydraulic steering systems inpublic traffic. The most wellknown of these in Europe are the EU directive 2009/66/EC and the ISO 5010
standard.

38 | © Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
Technical data common
Below common data are valid for all type of Danfoss Steering components:
OSPB, OSPC, OSPD, OSPF, OSPM, OSPL, OSPU, VSP, VSPP, OVR, OVPL, OLS, OSPE, EHPS, EHi
Ambient temperature

min.

–30°C

[–22°F]

max.

+60°C

[140°F]

Surface treatment

Permissible temperature assuming nonactivated steering unit

120°C [248°F] for 20 minutes

Oil temperaturemin., all types-30°C[-22°F]

max.: OSPB, OSPC, OSPD, OSPF, OSPM,
OSPL, OSPU, VSP, VSPP, OVR, OVPL, OLS,
and EHPS type O

100°C[212°F]

max.: OSPE, EHi and EHPS with otheractuator than PVED-CLS actuator

90°C[194°F]

max.: OSPE, EHi, and EHPS with PVED-CLS
actuatorsee oil temperature range in individualcomponent categories.

Recommended oil temperature

Oil viscosity

Recommended viscosity

Filtration

Steering torque, other OSP

30°C[86°F]

60°C[140°F]min.

10 mm2/s[59 SUS]max.

1000 mm2/s[4629 SUS]min.

12 mm2/s[66 SUS]max.

80 mm2/s[370 SUS]

Max. degree of contamination ON/OR
ISO 4406
LS/CN/PB

Temperature-difference between steering unit and otherhydraulics
Steering torque, OSPM

min.
max.

Normal steeringmax.

22 / 20 / 17
21 / 19 / 16∆10°C[∆18°F]

0.5 - 1.5 N•m[4.43 -13.3 lbf•in]

Manual steering1)

Max. 80 N•m[708 lbf•in]Momentary load

Max. 160 N•m[1416 lbf•in]Normal steering, OSPF

0.5 - 1.8 N•m[4.43-15.93 lbf•in]Normal steering, OSPL

1.5 - 4.0 N•m[13.3 - 35.4 lbf•in]Normal steering other OSP

0.8 - 3.0 N•m[7.08 - 26.55 lbf•in]

Manual steering1)

Max. 120 N•m[1062 lbf•in]Momentary load

Max. 240 N•m[2124 lbf•in]1) Steering units must not be used for continuous manual steering, max.1% of life cycle

Manual steering pressure
Under normal operating where the steering pump supplies an adequate oil flow at the required pressure,the maximum torque on the steering wheel will not exceed 5 N•m [44.2 lbf•in]. If the oil flow from thesteering system pump fails or is too small, the steering unit functions automatically as a manual steering
pump.
Manual steering can only be used for a limited control of the vehicle if a sudden drop of pump pressureor flow occurs.
The table below shows the nominal manual steering pressure (Pm) for all sizes of Danfoss steering units
type OSPM at a steering wheel torque of 80 N•m [708 lbf•in].
The values apply only if the suction conditions on the steering unit T port are adequate.

© Danfoss | March 2021

BC152886484183en-000701 | 39

Technical Information
General, Steering Components
General Information
OSPM
Pm

bar

32

50

63

80

100

125

80

65

50

40

[psi] [1813] [1160] [945] [725] [580]The table below shows the nominal manual steering pressure (Pm) for all types of Danfoss steering units
except OSPM at a steering wheel torque of 120 N•m [1062 lbf•in] a value which is considered to be themaximum torque an average size operator can exert. The values apply only if the suction conditions on
the steering unit T port are adequate.
OSP
Pm

bar

50

60

70

80

100

125

160

200

315

400

500

630

800

1000

120

100

85

75

60

50

40

30

20

15

12

10

8

6

[psi] [1740] [1450] [1235] [1090] [870] [725] [580] [435] [290] [217] [174] [145] [116] [87]Demands on steering columns
To ensure proper steering performance, the following demands must be fulfilled:• the steering column must not generate any axial or radial forces on the input shaft of the steeringunit• the steering column must only be provided with one bearing (in the top)•

the welded journal must be coaxial with the spigor hole of the column

Below are stated dimensions for the steering column spline shaft and foot plate to be fulfilled.
Data’s for steering columns for OSPB, OSPC, OSPD, OSPE, OSPF, OSPL and OSPU steering units:

Pitch angle

30°

Diametral pitch/stub pitch

16/32

Pitch Diameter∅19.05 [0.75]

Outer diameter∅20.3±0.1[0.80±0.01]

Smallest diameter∅16.5 +0.5
[0.65 +0.02]

Min. diameter over two
pins∅23.47 -0.1
[0.92 - 0.01]

Pin diameter∅3.048±0.001[0.12±0.001]

Min 3.0 [0.12]

0.4

12

0.4

A

Teeth

B

Involute spline data for steering column
Involute spline data acc. to ANSI B92.1[∅1.75 +0.1
-0 ]∅44.5 +0.1
-0

A

B
+0.02
S=T*+6.5 +0.6
-0.9 [0.26 -0.04]

min.15 full spline
P301 251*T=thickness of console plate.
When column is mounted directly on steering unit, S=6.5mm [0.26 in]

40 | © Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
Data’s for steering columns for OSPM steering units:

9

Outer diameter∅20 -0+0.11[0.79 -0+0.04]

Smallest diameter∅14 -0+0.11[0.55 -0+0.04]

0.4 A

Teeth

0.4 B

Involute spline data for steering column
Involute spline data acc. to DIN5482 A17x14

A

Max 4.0 [0.16]

Pin diameter∅3 ±0.001[0.12 ±0.001]

Pin flat grinded against
spline bottom

1.5 -0.1+0[0.10 -0.1+0]∅35±0.4[∅1.38±0.2]

Min. diameter between two ∅11.07 ±0.05
pins[0.43 ±0.01]

B

S=13±1-T*[S=0.51±0.04-T*]

min.15 full spline

]

[0

+
-0 0
.1

2.5
.10 -0+.10

1.00 1]±0 .00∅3 12±00.
[∅P301 252*T=thickness of console plate.
When column is mounted directly on steering unit, S=13mm [0.51 in]Steering components, main data and features
In EU directive 2009/66/EC specifies the maximum permissible steering-wheel rim force in an emergency
steering situation (Please consult the directives for the ruling values).
If, for example, the permissible steering wheel rim force is Fe = 350N [78.7 lbf] and the steering wheel
diameter SWd is = 0.381 m [15”], the steering torque Tsw will be =Tsw = Fe • (SWd/2) = 350 • (0.381/2) = 66.7 N•m [590 lbf•in]Accordingly, the obtainable maximum steering pressure will be lower than stated in the table in Technicaldata common on page 39.
With, for example, an OSPC 80, the maximum steering pressure Pmr, will be =Pmr = Pm table x Tsw/Ttable = 75 x 66/120 = 41 bar [598 psi].
Calculation of steering systems
Ackermann steering
Symbols:
ML (N•m) [lbf•in]: steering torque
F (N) [lbf]: steering force
GS (N) [lbf]: force on shaft (weight)e (mm) [in]: king pin off-set
B (mm) [in]: tyre breadthµS: friction coefficient© Danfoss | March 2021

BC152886484183en-000701 | 41

Technical Information
General, Steering Components
General Information
S (cm) [in]: piston stroke):r (m) [ft]: minimum effective radius arm for steering cylinders
r

S

GS
e

B

ML

150-268.10

The force on the shaft is 80.000 N (8.000kg) [17.984 lbf] King pin off-set is 100 mm. [3.94 in]. Tyre breadthis 200 mm [7.87 in]Friction coefficient between road and tyres is 0.7. Minimum effective radius arm for steering cylinders is
0.1 m [3.94 in].
According to Taborek's formula the total steering torque becomes

Cylinder piston rods must then produce a steering force of:
F= (ML/r) = (2667/0.1) N = 26.670 N [5995 lbf]
CylinderSymbols:
F (N) [lbf]: steering force
P (bar) [psi]: steering pressure
D (cm) [in]: internal diameter of cylinderd (cm) [in]: piston rod diameter
S (cm) [in]: piston stroke
V (cm3) [in3]: stroke volume

42 | © Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
A

B

C

150-243.10

When using only one differential cylinder, the number of steering wheel revolutions from lock to lock will
be different for each direction of rotation.
Use a piston seal in the cylinder to avoid leakage from one side of the piston to the other.
A: Differential cylinder
When max. steering pressure P is led to the largest area, the steering force becomes:
F = P • (π/4) • D2 • 10
At steering to the largest area, the stroke volume becomes:
V = (π/4) • D2 • S
With max. steering pressure P acting on the smallest area, the steering force becomes:
F = P • (π/4) • (D2 − d2) • 10
At steering to the smallest area, the stroke volume becomes:
V = (π/4) • (D2 − d2) • S
B: Balanced cylinder
F = P • (π/4) • (D2 − d2) • 10
V = (π/4) • (D2 - d2) • S
C: Cross-connected cylinders
F = P • (π/4) • (2D2 − d2) • 10
V = (π/4) • (2D2 − d2) • S
Calculation example of steering cylinder
Cross-connected cylinders are used. The steering force is 30.500 N [6857 lbf]
The steering pressure is 90 bar [1305 psi]. Piston stroke is 20 cm [7.90 in].
The relation between the piston rod diameter and internal diameter of the cylinder is(d/D) = (1/2) for the cylinder chosen.
Inserted in the formula for steering force 30.500 = 90 • (π/4) (2 (2d)2 − d2) • 10
© Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
the result is d = 2.5 cm [1 in] and D = 2 • d = 5.0 cm [2 in].
Stroke volume: V = (π/4) • (2 • 5.02 - 2.52) • 20 = 687 cm3 [41.9 in3]
A theoretical calculation of steering cylinders and steering pressure may result in inadequate steering
forces in many dynamic steering situations in practise.
An empirical rule verifies that adding an approx. 50 bar [725 psi] pressure to the theoretically requiredpressure usually always ensures a satisfactory steering performance.
Based on this empirical rule, the required size of cylinder can be calculated on basis of a steering pressurethat is 50 bar [725 psi] lower than the available system pressure.
Therefore, in the example illustrated above, the steering system must be able to work with a pumppressure of
90 bar [1305 psi]+ 50 bar [725 psi] = 140 bar [2030 psi]
Calculation example of steering unit
Symbols:
V cm3 [in3]: stroke volume
Vv cm3/rev [in3/rev]: steering unit displacementi (rev): required number of steering wheel revolutions from lock to lock
The required steering unit displacement is calculated from Vv = (V/i)
With a stroke volume of 687 cm3 [41.9 in3] and a required number of steering wheel revolutions from lockto lock of 3 to 4, the steering unit displacement will be between 172 and 229 cm3/rev. [10.56 and 13.97
in3/rev]. A steering unit with a displacement of
200 cm3/rev [12.20 in3/rev] will give 3.4 steering wheel revolutions.
Calculation example of pumpSymbols:
Vv (cm3/rev) [in3/rev]: steering unit displacementn (min-1) [rev/min]: required steering wheel speed
Q (l/min) [US gal/min]: oil flow
The oil flow is calculated from
Q = Vv • n • 10-3.
With a displacement of 200 cm3/rev [12.20 in3/rev] and a required steering speed of
100 min-1 [rev/min], the oil flow will be
Q = 200 • 100 • 10-3 = 20 l/min. [5.28 US gal/min]Steering wheel revolutions and steering speed

Recommended:
Number of steering wheel revolutions from lock to lock: 3 to 5.
Steering wheel speed: 100 to 150 min-1/min [rev/min]Steering wheel speed with engine at idle: min. 60 min-1/min. [rev/min]
Calculation of LS steering system with working hydraulics
Symbols:

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Technical Information
General, Steering Components
General Information
Q (l/min) [US gal/min]: required oil flow for the steering system
QA (l/min) [US gal/min]: required oil flow for the remainder of the hydraulic system
Qp (l/min) [US gal/min]: required pump flow
The priority valve ensures priority to the steering system under any situations. In some cases the steeringsystem can take all the oil flow from the pump.
When it is designed that the steering system and the working hydraulics do not require oil
simultaneously, the necessary oil flow from the pump QP will equal the higher of the two oil flows (QA or
Q).
When working hydraulics and steering system must have oil at the same time, the necessary oil flow fromthe pump QP will equal the sum of the two oil flows (QA + Q).
The necessary oil flow to the steering unit is 20 l/min[5.28 US gal/min]. Required for the working
hydraulics 40 l/min [10.56 US gal/min].
If it is acceptable that the working hydraulics drop in speed during steering then
the necessary oil flow from the pump will be: QP = QA = 40 l/min [10.56 US gal/min].
Calculation of steering system with flow-amplifier OSQA/OSQB
Symbols
V (cm3) [in3]: stroke volumei (min-1) [rev]: required number of steering wheel revolutions from lock to lockVv (cm3/rev) [in3/rev]: steering unit displacement
f: amplification factor of Flow-amplifier
Steering unit displacement and amplification factor of the flow-amplifier are calculated from:
Vv • f = (V/i)
Calculation of steering system for articulated vehicle
Should you wish to size a steering system for an articulated vehicle, Danfoss will carry out computer
calculations for you.
Please take a copy of the questionnaire overleaf, complete it, and send it to the Danfoss Sales
organization.

© Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
Articulated vehicle
Manufacturer:
Vehicle:Completed by:
Type:

Date:
Project:

Units used: fill in with X:

metric[US]

Weight of fully loaded vehicle: G max.=

kg

[lbf]

Max. speed of vehicle:

km/h

[mph]

min-1

[rev]

Max. steering pressure:

bar

[psi]

Displacement:

cm3

[in3]

Minimum speed:

min-1

[rev/
min]

Maximum speed:

min-1

[rev/
min]

Bucket width: W=

mm

[in]

Required number of steering wheel revolutions: i =Steering system pump:

LoaderType:

Other machines
Number of front axles:
Number of rear axles:

Complete form
A1 =

mm

[in]

A2 =

mm

[in]

B1 =

mm

[in]

B2 =

mm

[in]

D=

mm

[in]

d=

mm

[in]

± α max. =°°Notes:

E=

2 cylinders E = 1 1 cylinder, left E = 2 1 cylinder, right E = 3

A1

A1
R

L

L
A2

A2

A1
R

B2

B2

B2

B1

R

w

B1

A1

w

B1

w

L
A2

A2

150-317.10

46 | © Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
Pump for flow-amplifiers OSQA/OSQB
Symbols
Q (l/min) [US gal/min]:oil flow required for steering components

QA (l/min) [US gal/min]:oil flow required for working hydraulics

Qp (l/min) [US gal/min]:oil flow required from pump

Vv(cm3) [in3]:

steering unit displacementf:amplification factor of flow-amplifiern (min-1) [rev/min]:required steering speed

The integral priority valve in the flow-amplifier ensures priority to the steering system. When it isdesigned that the steering system and the working hydraulics do not operate simultaneously, the oil flow
required from the pump Qp will equal the higher of the two oil flows (QA or Q).
Q = VV • f • n • 10-3
When working hydraulics and steering system must have oil at the same time, the oil flow required fromthe pump QP will equal the total of the two oil flows (QA + Q).
Oil types
Mineral oils
When using mineral based hydraulic oil, we recommend the addition of a sufficient quantity of antiwear
additive of a type that is active under boundary lubrication conditions at low temperatures.
Mineral oils are normally suitable if they belong to one of the three following groups:
HM oil, possibly HV (ISO 6743/4, CETOP RP 91H) or H-LP oil (DIN 51524)
Automatic Transmission Fluids (ATF A)
SE- and CD motor oil (American Petroleum Institute (API))•••The large content of additives in motor oils may produce sediment that can block valves and filters. If
there is doubt about the suitability of an oil, please contact Danfoss Sales Organisation.
Non-flammable or biodegradable hydraulic fluids
To an increasing extent Danfoss steering components are being used in systems with non-flammable
hydraulic fluids.
These fluids normally belong to one of the following groups according to ISO 12922:
Oil in water emulsion: HFA
Water in oil emulsion: HFBWater/polymer solution: HFC
Waterfree synthetic fluids: HFD-U
Please contact the Danfoss Sales Organisation regarding the use of non-flammable or biodegradable
fluids
Sealing materials
The seals in steering components are of nitrile rubber NBR (Buna N) and teflon PTFE.
If synthetic fluid is to be used in the steering system, please contact the Danfoss Sales Organization
regarding sealing material.

© Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
Oil temperature
Oil life will be drastically reduced because of oxidizing if the operating temperature exceeds 60 °C [140°F]
for long periods.
A rule of thumb is that oil life is halved for each 8 °C [46.4°F] in excess of 80 °C [176°F] .
Impurities in the oil, e.g. particles or water, will further reduce its life.
Particle content, degree of contamination and filtering
Particle content, degree of contamination
The oil must be filtered to prevent the particle content from exceeding an acceptable level,
corresponding to an acceptable degree of contamination. The maximum ISO degree of contamination(see ISO 4406 or CETOP RP 70) is• for load sensing, closed center steering components and power beyond steering units: 21/19/16• for open center steering components: 22/20/17
Filtering
How fine the filtering must be and where the filters are to be placed is always a compromise.
In systems with a good air filter and effective dust sealing, and which operate in clean
surroundings, the degree of contamination can normally be kept within the limits laid down by using a
return filter of 25 µm nominal (40-50 µm absolute) or finer.
Conversely, systems operating with a poor air filter and inadequate dust sealing - in dusty surroundings will often require more than one filter of 10 µm absolute. The filters can be pressure or return filters.
Installation

•
•
•
•
•
•
•
•
•
•
•
•
•
•

48 | © Danfoss | March 2021

Never paint steering unit on steering column surface to avoid misalignment between steering unit
and column.
Install the steering column so that it cannot generate any axial or radial forces on the input shaft ofthe steering unit.
All hydraulic components should be placed so that they are easily accessible.
All hydraulic components should be installed outside the cabin of the vehicle.
There should be manometer connections in pump and tank lines.
Install the cylinders with the ports facing upwards to avoid air pockets.
Mounting surfaces should be flat in order to ensure effective contact.
Hydraulic pilot lines must be fitted in such a way that air pockets are avoided.
Install the hydraulic components as stated in their individual installation instructions.
Installation instructions are enclosed inside the packaging or can be ordered from Danfoss Power
Solutions, sales organization.
The hydraulic components must not be forced or twisted into alignment by the fixing screws.
Packing yarn, teflon, and other unsuitable sealing material must not be used on port adaptors. Use
bonded seals, O-rings, steel washers, and similar materials.
Do not remove the plastic plugs until pipes and hoses are to be fitted.
When removing the plastic plugs, make sure that no paint flags or other dirt particles are entering theports of the hydraulic components.

BC152886484183en-000701

Technical Information
General, Steering Components
General Information•••

Never tighten the screwed connections with a torque higher than the max. tightening torques statedin the instructions.
The oil must have a contamination level better than the ISO 4406 code stated in Technical data
common on page 39
Always refill the system through a filter.

Tightening torques
Connections

Recommended tightening torque N•m [lbf•in]With cutting edge

With copper washer With alum. washer

O-ringG 1⁄4

35 [309]35 [309]-G 3⁄8

70 [619]45 [398]

50 [442]-G 1⁄2100 [885]

55 [486]

80 [708]-G 3⁄4

180 [1593]

90 [796]130 [1150]-

7⁄16-20 UNF

-

-

-

20 [177]3⁄4-16 UNF

-

-

-

60 [531]7⁄8-14 UNF

-

-

-

90 [796]

1 1⁄16-12 UN

-

-

-

120 [1062]

M12 • 1.5

30 [265]

20 [177]

30 [265]

25 [221]M18 • 1.5

80 [708]

55 [486]

70 [619]50 [442]

M22 • 1.5

100 [885]

65 [575]

80 [708]

60 [531]

9/16 - 18 UNF, ORFS

-

-

-

25 [221]

11/16 - 16 UN, ORFS

-

-

-

27 [239]

35 [309]

Danfoss Steering Components can withstand the tightening torques stated. However it is recommended
to use torque levels stated by supplier of fittings.
Starting up and running in

•
•
•
•
•
•

Start the prime mover and where possible allow it to run at the lowest speed.
Check the direction of pump shaft rotation.
Any bleed screws must be left open until oil emerges without foam.
In load sensing systems ensure that all signal lines are full of oil.
Start steering slowly from one end-lock to the other for a minimum of five cycles to bleed out all air.
Signs of air in the hydraulic system‒ foam in the tank‒ jerky operation of actuator motor or cylinder‒ noise••••© Danfoss | March 2021

Refill again, if necessary.
The system should not be loaded until completely bled.
The hydraulic system is checked for tightness and satisfactory function.
Check pressure in P and T:

BC152886484183en-000701 | 49

Technical Information
General, Steering Components
General Information‒ Max pressure P-T, when steering up against end lock, must match specification.
‒ T- pressure absolute: T- pressure must be above atmospheric pressure in any steering situation,•

also when changing steering direction rapidly. In some steering system it will be necessary tohave installed back pressure valve in T-line to ensure positive tank pressure in any steeringsituation. See Examples of steering systems on page 51 for back pressure valve installations.
After running in: change the oil filter, if necessary.

Maintenance

•
•
•
•

50 | © Danfoss | March 2021

Careful maintenance is essential to the reliability and life of the hydraulic system.
Oil, oil filters, and air filters must be changed in accordance with the supplier’s instructions.
The condition of the oil must be checked at suitable intervals.
System tightness and oil level must be checked frequently.

BC152886484183en-000701

Technical Information
General, Steering Components
General Information
Information on labels
The label on all Steering components has included:
Danfoss logo
Type designation
Code number
Serial number
Bar codes, includes information of code number and serial number

•
•
•
•
•

The serial number has 8 characters stating this information given by an example:

49 3 B 6000
Production week
Production year
Production day: A=Monday, B=Tuesday etc.
Consecutive no

Examples of steering systems
OSPC ONOSPC ON steering units contain one or more of thefollowing possible valve functions:• pressure relief valve• shock valves• suction valves• check valve

L

R
OSPC ONP

T

150-367.11© Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
OSPC OROSPC OR steering units contain one or more of thefollowing possible valve functions:• pressure relief valve• suction valves• check valve• shock valves if needed

L

R
OSPC ORP

T

150-429.11

OSPC LS + OLSA
Steering unit with flange mounted priority valve OLSA
and steering column with sensor.
When the driver turns the steering wheel, the steering
wheel sensor sends a signal to the relay box activating
the electric motor that drives the hydraulic system pump.
The system must also include a signal source in theworking hydraulics.
A PVRES control lever for example.
The system is therefore energy-optimised, so that thehydraulic pump runs only when the hydraulic functions
are active.

Columnwith sensor

OSPC LS

L

P

T LS

R
OLSA

P

T

EF

PVG 32M

PVRES

152B77.11

52 | © Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
OSPF + OLS
Load sensing steering system with variable displacementpump.
The pump and the working hydraulics circuit must be
protected by a separate pressure relief valve.

L

R
OSPF LS

LS

P

T

CF

LS

EF

OLS

P

150-394.11

OSPD LS
Steering unit with two rotary meters.
With OSPD even heavy vehicles can in many cases fulfil
legislations and be steered without the emergency
steering pump. An OSPD makes it possible to select a
ratio between normal steering displacement andemergency steering displacement up to a factor of 5.
The pump and the working hydraulics circuit must be
protected by a separate pressure relief valve.

L

P

R

T

LS

P301 760.B© Danfoss | March 2021

BC152886484183en-000701 | 53

Technical Information
General, Steering Components
General Information
OSPU LS
Steering unit with amplification.
With OSPU even heavy vehicles can in many cases fulfil
legislations and be steered without the emergency
steering pump.
OSPU allows the selection of an amplification factor of 2,
3 or 4.
In case of working hydraulic connected to EF port ofpriority valve, the pump and the working hydraulics
circuit must be protected by a separate pressure relief
valve.

L

P

R

T

LS

P301 761

54 | © Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
OSPBX LS and OSQA
The pilot pressure relief valve in OSQA only protects the steering circuit. The pump and the working
hydraulics circuit must be protected by a separate pressure relief valve.

CL

CR

P
L
OSQA

R
L

R

P

T
LS

OSPBX LS
T
LS

EF

PP
HP

HT

150F57.10© Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
2 x OSPBX LS and OSQB
The steering components are connected by three shuttle valves. The pilot pressure relief valve in OSQB
only protects the steering circuit.
The pump and the working hydraulics circuit must be protected by a separate pressure relief valve.
Steering systems with flow-amplifiers make it possible to connect working hydraulics to the EF
connection. The built-in priority valve ensures first priority to the steering circuit.
When the steering wheel is turned, the priority valve ensures that the necessary oil flow is led to thesteering circuit. The rest is available for the working hydraulics.

CL

CR

P
L
OSQB

R
L
OSPBX LS
P

R
T

L

R

P

T

OSPBX LS
T
LS

EF

PP

HP

HT

150F58.10

56 | © Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
OSPBX LS and OSQA shown with electrically driven pump for emergency steering.amplification
during emergency steering
The pump for emergency steering is operated when the pressure in the HP line is below the stand-by
level. The pump for emergency steering supplies the HP line with oil.
So amplification is maintained during emergency steering. The pilot pressure relief valve in OSQA only
protects the steering circuit.
The pumps and the working hydraulics circuit must be protected by separate pressure relief valves.

CL

CR

P
L
OSQA

R
L

R

P

T
LS

OSPBX LS
T
LS

EF

PP
HP

HT

150F60.10© Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
EHPS - type 1 steering valve with PVG 32, OSPCX pilot steering unit and PVRES joystick
The vehicle can be steered with either the PVRES joystick or with the OSPCX pilot steering unit. The signal
from the steering unit has priority on simultaneous activation of steering wheel and joystick.
TP

M

PVG 32

LS

PVRES

A
B

A
B

A
B CL

PVES

CR
EHPS

Electronics

type 1

L
2

4

R

LE
RE

Ps
1

3

PE

T

L

P

R

OSPCX CN

TE

Ts
T

P

T

150-575.14

58 | © Danfoss | March 2021

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Technical Information
General, Steering Components
General Information
EHPS - type 2 steering valve with control module PVED, OSPCX pilot steering unit and joystick
The vehicle can be steered either:
automatically with a signal from an external signal source, e.g. range sensor or a GPS signal, or••

manually with a joystick, or with an OSPCX pilot steering unit.

The signal from the steering unit has priority:
When the steering wheel is activated, the signal from the automatic steering valve discontinues and withsimultaneous activation of steering wheel and joystick, the turning direction of the steered road wheels
will correspond to the direction of rotation of the steering wheel.
The signal from the steering wheel sensor gives:
variable steering wheel ratio•••

Zero-slip function: the steering wheel position corresponds to the position of the steering cylinder.
The pump and the working hydraulics circuit must be protected by a separate pressure relief valve.
TP

M

PVG 32

LS

PVRES

A
B

A
B

A
B CL

PVES

CR
EHPS

Electronics

type 1

L
2

4

R

LE
RE

Ps
1

3

PE

T

L

P

R

OSPCX CN

TE

Ts
T

P

T

150-575.14© Danfoss | March 2021

BC152886484183en-000701 | 59

Technical Information
General, Steering Components
General Information
OSPE in system with variable pump and GPS steering
The pump must have a built in pilot pressure relief valve to protect the OSPE, the priority valve part, theworking hydraulics and the AUX function. AUX can be a brake system, which must have limited oil
consumption to ensure steering capability in any case.
Alternative pressure protection must be present in working and in AUX-hydraulic.
Vehicle speed

GPS

Display/MMI

OSP
L

R

Joystick

Mini wheel
SASA

EH

P
Rr Lr

LS

PVED CLS

PE

TE

LS
P

EF

T

L

R

AUX

Prime
mover

Working
HydraulicCC
P301 178

60 | © Danfoss | March 2021

BC152886484183en-000701

Technical Information
General, Steering Components
General Information
Load sensing steering system and load sensing working hydraulics with common oil supply from afixed displacement pump
The pump oil flow is fed in from a priority valve OLS 120 or OLS 160, which ensures priority to steering.
The built-in pilot pressure relief valve in OSPC LS protects the steering circuit.
The built-in pilot pressure relief valve in Danfoss proportional valve PVG 32 protects the working
hydraulics circuit.
The first working hydraulics section is shown with a Danfoss hydraulic motor .
Shock and suction valves are built into the proportional valve.
The second working hydraulics section is shown with a Danfoss hydraulic motor.
The third working hydraulics section is shown with LS pressure relief valves built into the proportional
valve. Hereby maximum working pressure can be set separately for port A and port B.
Please contact the Danfoss Sales Organization regarding assembly possibilities for your application.
OMS

A

L

R

OMV

B

A

B

A

B

PVG 32
OSPC
LS
M
LS

LS
P
CF

T

T

P

EF

LS
OLS

P

150-437.11© Danfoss | March 2021

BC152886484183en-000701 | 61

Products we offer:

•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
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•
•
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Cartridge valves
DCV directional control
valvesElectric converters
Electric machines

Danfoss Power Solutions is a global manufacturer and supplier of high-quality hydraulic andelectric components. We specialize in providing state-of-the-art technology and solutions
that excel in the harsh operating conditions of the mobile off-highway market as well as themarine sector. Building on our extensive applications expertise, we work closely with you toensure exceptional performance for a broad range of applications. We help you and othercustomers around the world speed up system development, reduce costs and bring vehicles
and vessels to market faster.

Gear motors

Danfoss Power Solutions – your strongest partner in mobile hydraulics and mobile
electrification.

Gear pumps

Go to www.danfoss.com for further product information.

Hydraulic integrated
circuits (HICs)
Hydrostatic motors

We offer you expert worldwide support for ensuring the best possible solutions foroutstanding performance. And with an extensive network of Global Service Partners, we also
provide you with comprehensive global service for all of our components.

Electric motors

Hydrostatic pumps
Orbital motors
PLUS+1® controllers
PLUS+1® displays
PLUS+1® joysticks andpedals
PLUS+1® operator
interfaces
PLUS+1® sensors
PLUS+1® software
PLUS+1® software services,support and training
Position controls andsensors
PVG proportional valves
Steering components andsystems
Telematics

Local address:

Hydro-Gear
www.hydro-gear.com
Daikin-Sauer-Danfoss
www.daikin-sauer-danfoss.com

Danfoss
Power Solutions (US) Company
2800 East 13th Street
Ames, IA 50010, USA
Phone: +1 515 239 6000

Danfoss
Power Solutions GmbH & Co. OHG
Krokamp 35
D-24539 Neumünster, Germany
Phone: +49 4321 871 0

Danfoss
Power Solutions ApS
Nordborgvej 81
DK-6430 Nordborg, Denmark
Phone: +45 7488 2222

Danfoss
Power Solutions Trading(Shanghai) Co., Ltd.
Building #22, No. 1000 Jin Hai Rd
Jin Qiao, Pudong New District
Shanghai, China 201206
Phone: +86 21 2080 6201

Danfoss can accept no responsibility for possible errors in catalogues, brochures and other printed material. Danfoss reserves the right to alter its products without notice. This also applies to products
already on order provided that such alterations can be made without subsequent changes being necessary in specifications already agreed.
All trademarks in this material are property of the respective companies. Danfoss and the Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.

© Danfoss | March 2021

BC152886484183en-000701