Danfoss OSQA, Service Manual

Page: 40 / 44

This section describes minimum tests needed, when the OSQ steering valve has been disassembled and
reassembled.
OSQ system
P
P
LS LS
PP
T
OSPBX LS
CR CL
OSQA
EF
HP HT
T
R
R
L
L
kwa1468255007577
Set-up for testing
Use universal hydraulic work bench with pump capacity: 140 l/min and up to 240 bar pressure for relief
valve setting and steering test.
If the recommended pump flow is not available, then take the characteristic of pilot relief valve into
consideration. Reference
OSPB/C/F/D/L LS Steering Units, OLS Priority Valves, OSQ Flow Amplifiers Technical
Information , BC00000009, the HP/Qp characteristic in the OSQ chapter, under Technical data.
The hydraulic oil must be with a viscosity of 21 cSt. at 50° and with maximum degree of contamination
according to ISO 4406: 21 / 19 / 16.
1. Connect double rod cylinder to CL and CR ports of OSQ.
2. Connect pilot steering unit OSPBX LS to OSQ: L to L, R to R, P to P, T to T, LS to LS.
3. Connect HT and EF port of OSQ to tank of pump station.
4. With LS pump in pump station: connect LS of OSQ-OSP to LS of pump.
5. Connect pressure gages to all ports of OSQ.
6. Connect steering column and steering wheel to the input shaft of the OSPBX steering unit.
T pressure should not exceed approximately 5 bar. Maximum allowed T pressure is 15 bar. Pump supply
circuit must be adjusted not to exceed 240 bar P-T.
Steering test using steering unit type OSPBX LS
During the testing the following must not occur: motor effect, disturbing vibrations, noise, sticking or
other irregularities.
1. Start the pump.
The pump flow should be approximately 40 l/min and pump pressure control should be
approximately 70 bar.
2. Let the supplied oil flow through the OSQ for a few minutes.
a) At the same time, rotate the steering wheel a few times in both directions to bleed air from the
unit and the system.
3. Operate the steering wheel by approximately 10 rpm in a smooth manner from end stroke to end
stroke of the steering cylinder for at least 5 cycles.
a) Make sure pressure P-T, 70 bar can be achieved, when steering against end stroke.
If this is not possible, the adjusting screw of the pilot relief valve (see item 23, Exploded view on
page 6) must be turned clockwise until P-T, 70 bar is achievable.
Service Manual
OSQA/OSQB
Testing
40 | © Danfoss | July 2016 HN25D293 | AX00000127en-US0101