Parker VO40 Manual

VO40 Open-Center
Directional Control
Valve
Catalog HY17-8505/UK
April 2007

II Parker Hannifin Corporation
Catalog HY17-8505/UK Open-Center Directional Control Valve
VO40
Offer of Sale
Please contact your Parker representation for a detailed ”Offer of Sale”.
FAILURE OR IMPROPER SELECTION OR IMPROPER USE OF THE PRODUCTS AND/OR SYSTEMS DESCRIBED
HEREIN OR RELATED ITEMS CAN CAUSE DEATH, PERSONAL INJURY AND PROPERTY DAMAGE.
This document and other information from Parker Hannifin Corporation, its subsidiaries and authorized distributors provide
product and/or system options for further investigation by users having technical expertise. It is important that you analyze all
aspects of your application, including consequences of any failure, and review the information concerning the product or sys-
tem in the current product catalogue. Due to the variety of operating conditions and applications for these products or systems,
the user, through its own analysis and testing, is solely responsible for making the final selection of the products and systems
and assuring that all performance, safety and warning requirements of the application are met.
The products described herein, including without limitation, product features, specifications, designs, availability and pricing, are
subject to change by Parker Hannifin Corporation and its subsidiaries at any time without notice.
WARNING
!

III Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
Contents
Introduction.............................................................................................................................................................1
Technical Information
General Description..........................................................................................................................................3
Operation..........................................................................................................................................................3
Benefits ............................................................................................................................................................3
Specifications ...................................................................................................................................................4
Weights.............................................................................................................................................................4
Connections .....................................................................................................................................................4
Performance Curves.........................................................................................................................................5
Environmental Characteristics..........................................................................................................................5
Schematic Circuit Types ...................................................................................................................................6
Dimensions....................................................................................................................................................7-8
Handle Actuation vs. Spool Direction ...............................................................................................................9
Ordering Information
How to Order ..................................................................................................................................................10
General Valve Assembly.................................................................................................................................11
Inlet Cover .................................................................................................................................................12-13
Outlet Cover ..............................................................................................................................................14-15
Work Sections ...........................................................................................................................................16-20
Mid-Inlet..........................................................................................................................................................21
Assembly Configuration Form ............................................................................................................................22

IV Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
Conversion factors
1 kg = 2.2046 lb
1 N = 0.22481 lbf
1 bar = 14.504 psi
1 l = 0.21997 UK gallon
1 l = 0.26417 US gallon
1 cm3= 0.061024 in3
1 m = 3.2808 feet
1 mm = 0.03937 in
9/5 °C + 32 = °F

1Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
Breadth of Line
Parker Hannifin is a Fortune 500
company with sales of $9 billion
and over 400,000 customers in 43
countries. Parker is the world’s
leading supplier of motion control
components and system solutions
serving the mobile, industrial
and aerospace markets.
Parker is your single source
for any hydraulic valve require-
ment. We provide a wide selection
of open-center and load-sense
directional control valves for any
construction, off-highway, or on-
highway application. Many of our
open-center valves can be adapted
and used as closed-center, constant-
pressure, and constant-pressure
unloaded valves. Each of these
technologies offers unique features
for improved machine performance
over traditional, open-center control
valves.
When remote control is required,
Parker provides a broad line of
pilot controllers that are compact
and pressure-matched with our
control valves to provide consistent
and optimized machine control.
There are a variety of electric-
switch handle options available
for additional function control by
the operator.
Parker’s premier IQAN electron-
ics packages range from simple
stand-alone controllers to large,
multiple CAN bus systems with
color displays. For example, IQAN
interfaces with new electronic
diesel engines over the SAE J1939
CAN bus.
Package components are
designed and tested for
mobile applications to
help increase machine
Total Machine
Motion Control
You can turn to us for all your
mobile motion control solutions.
We offer stand-alone valves, as well
as custom-designed manifolds with
integrated directional control valves.
No matter what type of system you
choose, Parker solutions provide
top-notch performance and reli-
ability. Our systems are optimized
to reduce complexity, size, cost, and
fluid leakage. Therefore, working
with Parker can significantly cut
your machine-build time.
uptime. The IQAN valve drivers
offer superior control of propor-
tional hydraulic functions resulting
in increased machine productivity.
Non-programmers find IQAN’s
programming interface easy to use,
reducing development time. Fur-
thermore, excellent diagnostic tools
and remote modem connection help
cut field service time.
Introduction

2Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
Customer Service
with A Global Reach
Parker’s worldwide network of field
sales engineers and Mobile Systems
Engineers (MSEs) are the best in
the business. A field sales engineer
works closely with you, acting as a
single point of contact to evaluate
applications and design solutions.
MSEs support field sales efforts by
managing difficult design problems
and complex circuit design.
State-of-the-Art
Manufacturing
Parker is committed to using lean
manufacturing to eliminate waste
while streamlining processes.
Lean technology helps us meet
customer request dates quickly
and cost-effectively. We also rely
on state-of-the-art equipment and
technology, such as computer-
aided machining, to ensure
product quality.
We regularly invest in our ISO 9001
certified manufacturing facilities
because we are committed to
meeting all international standards
for safety and quality. The hydraulic
valves we manufacture comply with
relevant ISO, CSA, CE, and AMEX
standards.
In addition, Parker hydraulic valves
and valve manifolds are fully tested
and certified before being released
to the customer. You can expect
Parker hydraulic valves to work the
first time, every time.
You also benefit from Parker
Mobile Technology Centers
(MTCs) that are staffed by specially
trained distributors who provide
only the highest levels of customer
service. These one-stop shops offer
complete hydraulic systems design
for mobile applications, as well as
technology services such as diag-
nostics, troubleshooting, computer
design, testing, and integration of
electronic controls.
Finally, our thousands of depend-
able distributors are strategically
located in your markets. They carry
inventory to meet specific, local
market needs, and they ensure that
products arrive when and where
they are needed. You can count on
Parker distributors to minimize
downtime.
To locate your nearest distributor
for the latest information on the
VO40 Directional Control Valve, or
our entire mobile valve line-up, visit
us at www.parker.com/eurohyd.
Introduction

3Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
General Description
The VO40 is an open-center directional control valve
with the flexibility of sectional construction. Consis-
tent with this technology, it is simple in its application,
reliable, easy to troubleshoot, and cost effective. The
global design reflects the performance and quality ex-
pected by today’s machine designers. Spools have me-
tering notches in the three critical areas – open- center,
parallel path and tank, which optimizes simultaneous
metering. Contemporary honing technology is used to
deliver low work port to tank leakage. Additionally, each
work section has a transition check to ensure that a
load does not “dip” during simultaneous operation. All
of these features, plus those listed below, were intend-
ed to take machine controllability to the next level.
Operation
The VO40 incorporates traditional open-center technol-
ogy. It is usually interfaced with a constant flow pump,
whose flow is routed directly to tank when the spools
are in neutral. When one or more spools are selected,
flow is directed to the actuators. The throttling of that
flow depends upon the spool position and the design of
the metering notches. Spool notches can be designed
to accommodate resistive loads (meter-in) and nega-
tive loads (meter-out). To accommodate multiple pump
circuits, split flow and combined flow mid inlets are
available.
Benefits
•Enhanced metering – especially during simultaneous
operation, this is accomplished by having notches in the
three critical areas of the spool: open center, parallel path
and tank.
•Improved simultaneous metering – having a transition
check in each work section ensures that a load does not
“dip” downward when metering two or more work-sections.
•Repeatability – consistent metering from valve to valve
is achieved by flycutting all of the critical cast lands. This
means that the notch position relative to the spool stroke
is controlled and predictable. The result is consistent
machine control.
•Reduced operator fatigue – the open-center core is
a split wing or “Y” core design, which provides for a
consistent lever force when selecting the spool from
neutral to both power positions.
•Reduced function drift – low internal leakage
accomplished thru the use of contemporary honing
technology. Also, for those functions requiring near zero
drift, pilot-operated checks are available.
•Small footprint – port accessories are installed vertical
to the spool, allowing the handle to be positioned closer to
the valve body.
•Ease of service – the bottom two stud assemblies are
slotted, enabling a work section to be replaced without
completely disassembling the valve assembly. This is
accomplished by loosening the top tie bolt and then lifting
the section out of the assembly. Downtime is minimized.
•Easy conversion from a left-handed to a right-handed
section – the work section housing and spool are
symmetrical, which enables the spool to be inserted in
either end of the housing.
•Improved spool seal life – the enclosed handle assembly
protects the spool and spool seal area from contamination
and the potential corrosion.
Technical Information

4Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
Specifications
Pressures Inlet Port: 300 bar (4350 PSI)
Tank Port: 50 bar (725 PSI)
Work Ports: 300 bar (4350 PSI)
Flow Rates
(maximum
recommended)
40 LPM (10.6 GPM)
Internal Pilot
Pressure
Required for solenoids –
contact Parker
Spool Leakage
from work port
to tank
Max. 6 mL/min @172 bar (2500 PSI)
Oil temp. 50ºC (122ºF), and viscosity
40 cSt
Weights
Weights are approximate due to number of variations
available.
Inlet with relief 1.92 kg (4.2 lbs)
Outlet 1.88 kg (4.1 lbs)
Work section with reliefs and
manual actuator
1.93 kg (4.3 lbs)
Work section and manual actuator
without reliefs
1.98 kg (4.4 lbs)
Work Section, PO Checks with
manual actuator
2.1 kg (4.6 lbs)
Joystick assembly 0.8 kg (1.8 lbs)
Connections
Standard valves are available in 3/8" BSP (DIN 3852/2), SAE-6
or SAE-8 (J1926/1).
Connection Location SAE -8 SAE-6 BSP
P1, P2 Inlet ¾-16 UNF >\zn-18 UNF C\,-19
T1, T2 Inlet ¾-16 UNF >\zn-18 UNF C\,-19
P3 Outlet ¾-16 UNF >\zn-18 UNF C\,-19
T3 Outlet ¾-16 UNF >\zn-18 UNF C\,-19
PB1 Outlet ¾-16 UNF >\zn-18 UNF C\,-19
Work Ports Work
Sections ¾-16 UNF >\zn-18 UNF C\,-19
GAGE
PORT Inlet M\zn-20 UNF M\zn-20 UNF ¼
PC
(Hyd. Conn.)
Work
Sections M\zn-20 UNF M\zn-20 UNF ¼
PT
(Pneu.Conn.)
Work
Sections Z\, NPT Z\, NPT Z\, NPT
Technical Information

5Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
3010 20
7.92.6 5.3
50
13.2
Flow
0
LPM
GPM
0
43.5 3
87.0 6
130.5 9
174.0
217.5
PSI
12
15
Bar
Pressure
40
10.6
Pressure Drop - Open Center P T
Top Inlet to Top Outlet
→
T
P
8 Section Valve
3 Section Valve
1 Section Valve
3010 20
7.92.6 5.3
50
13.2
Flow
0
LPM
GPM
0
43.5 3
87.0 6
130.5 9
174.0
217.5
PSI
12
15
Bar
Pressure
40
10.6
Pressure Drop - Open Center P T
Side Inlet to Side Outlet
→
PT
8 Section Valve
3 Section Valve
1 Section Valve
3010 20
7.92.6 5.3
50
13.2
Flow
0
LPM
GPM
0
43.5 3
87.0 6
130.5 9
174.0
217.5
PSI
12
15
Bar
Pressure
40
10.6
Pressure Drop - A T
Cylinder Port to Side Outlet
→
3010 20
7.92.6 5.3
50
13.2
Flow
0
LPM
GPM
0
43.5 3
87.0 6
130.5 9
174.0
217.5
PSI
12
15
Bar
Pressure
40
10.6
Pressure Drop - P A
Top Inlet to Cylinder Port
→
A
P
8 Section Valve
3 Section Valve
1 Section Valve
8 Section Valve
3 Section Valve
1 Section Valve
T
A
Environmental Characteristics
The valve can be mounted in all conceivable directions.
However, the mounting base should be flat and stable so
that the valve is not subjected to strain.
While the o-rings in the valve are normally of nitrile rub-
ber, there are a number of special fluorocarbon variants.
Please contact Parker for further information.
Temperature
Oil temperature, working range:
+20°C to 90 °C (68 to 194 °F)*
Filtration
Filtration must be arranged so that Target Contamination
Class 20/18/14 according to ISO 4406 is not exceeded.
For the pilot circuit, Target Contamination Class 18/16/13
according to ISO 4406 must not be exceeded.
Hydraulic Fluids
Best performance is obtained using mineral-base oil of
high quality and cleanliness in the hydraulic system.
Hydraulic fluids of type HLP (DIN 51524), oil for automatic
gearboxes Type A and engine oil type API CD can be
used.
Viscosity, working range: 15-380 mm2/s (15-380 cST)**
Technical information in this catalog is applicable at
an oil viscosity of 30 mm2/s (30 cST) and temperature
of 50 °C (122 °F) using nitrile rubber seals.
* Product operating limits are broadly within the above range, but
satisfactory operation within the specification may not be accom-
plished. Leakage and response will be affected when used at tem-
perature extremes and it is up to the user to determine acceptability
at these levels.
** Performance efficiency will be reduced if outside the ideal values.
These extreme conditions must be evaluated by the user to establish
suitability of the product’s performance.
NOTE: ISO VG 46 oil @ 50 °C
Performance Curves
Technical Information

6Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
Circuit Types – Parallel Circuit
In the open-center parallel circuit, oil flows through the open-center passage when all of the spools are in neutral.
When spools are shifted, oil is diverted into the parallel path and available to each of the selected work-sections.
Simultaneous operation can be achieved, when two or more spools are selected. However, since oil will take the
path of least resistance the operator must meter the flow to each function to get a desired function speed.
Circuit Types – Tandem Circuit (Priority)
In the open-center tandem circuit, oil flows through the open-center passage when all of the spools are in neutral.
Tandem work-sections are fed from the open center and the parallel path is blocked. A tandem work-section will
give priority to an upstream work-section.
BA
P1
[26]
T1
[24]
G
BAB A T4
[34]
BA
P1
[26]
T1
[24] T4
[34]
BABA
Technical Information

7Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
191.0 (7.51)
27.0
(1.06)
80.9
(3.19)
15.0
(0.59)
87.0 (3.42)
92.0 (3.62)
20°
A = 76.0 (3.00) + 32.0 (1.26) x No. WORK STATIONS
B = 32.0 (1.26) + 32.0 (1.26) x No. WORK STATIONS
15°
15°
132.7
(5.23)
15°
15°
207.5
(8.16)
32.0
(1.26)
32.0
(1.26)
32.0
(1.26)
9.4±0.4
(0.37±0.01)
70.0 (2.76)
40.0 (1.57)
213.6
(8.41)
70.0
(2.76)
140.0
(5.51)
161.8
(6.37)
25.0
(0.98)
A
B
B
Inch equivalents for millimeter dimensions are shown in (**)
Assembly
Spool Stroke of Work Sections
3-Position Spool 4-Position Spool
(Float)
15°
15°
10°
15°
15°
25.0
(0.98)
9.5
(0.37)
FLOAT STROKE
5.5
(0.22)
5.5
(0.22)
114.2 (4.50)
5.5
(0.22)
5.5
(0.22)
84.0 (3.31)
STROKE STROKE
STROKESTROKE
25.0
(0.98)
Dimensions
US

8Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
Inch equivalents for millimeter dimensions are shown in (**)
Mechanical Joystick
6.00
(0.236)
16.25
(0.640)
5.50
(0.216)
∅4.80 (0.189)
62.0 (REF)
(2.44)
92.0
(3.62)
37.0
(1.46)
∅30.0
( 1.18)∅
Dual Actuator
Pneumatic Actuator
16°
16°
16°
16°
20°
295
(11.6)
58
(2.3)
58
(2.3)
94
(3.7)
Float
43
(1.7)
102
(4.0)
137
(5.4)
Float
18
(0.7)
20°
Dimensions
Handle Rod
R1
140
20
M8x1
Ø7,3
Ø13
Ø11
42
30 R9
Ø7,35

9Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
Handle Actuation vs. Spool Direction
Push Handle
Pull Handle
• Spool Out
• Energize port “B”
• Port “A” to tank
• Spool In
• Energize port “A”
• Port “B” to tank
Left-Hand Joystick
Spool OUT - Section 1
Power to “B” Port
Spool IN – Section 1
Power to “A” Port
Spool IN – Section 2
Power to “A” Port
Spool OUT – Section 2
Power to “B” Port
Right-Hand Joystick
Spool OUT - Section 2
Power to “B” Port
Spool IN – Section 2
Power to “A” Port
Spool OUT – Section 1
Power to “B” Port
Spool IN – Section 1
Power to “A” Port
A B
TANK
OPEN
CENTER
PARALLEL
PATH
TANK
OPEN
CENTER
PARALLEL
PATH
Note:
Circuit reflects spool
position, not handle
position.
Technical Information

10 Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
How to Order the VO40 Valve Assembly
A specification sheet is located in the back of this book, and is also available in an electronic Excel format on our
web site. This form should be used to configure a valve assembly. The layout starts from the inlet cover on the left,
work sections and mid-inlets in the middle and the outlet cover on the far right. Each field will require an entry, and
the fields are represented with a position reference [ ] to help guide you to the option codes listed in the catalog
pages 11 to 21.
Example: Inlet Cover (Sect #1)
Customer has 23 l/min pump flow, requires
a pilot operated main relief set 140 bar and
wants all SAE-8 work ports.
• Reference position [4] calls out the thread
option for the entire valve assembly (SAE
or BSP) (“U8” is the code for all SAE-8
size ports).
Note: There is a separate specification
sheet which utilizes metric units.
• Reference position [12] calls out the
system flow and can be listed in LPM or
GPM depending on which spec sheet you
are using (23 is entered for flow).
• Reference position [15] gives you an
option for a standard type inlet “I” or
an unloader type inlet cover “IU” (“I” is
entered for std inlet cover).
• Reference position [16] indicates the type
of main relief valve: (“PB” is the code for
a pilot operated RV).
• Reference position [17] Enter desired
relief valve setting (140 bar is entered).
• Reference position [17C] Enter desired
flow for relief valve setting (23 l/min is
entered).
• Reference position [24-27] calls out the
inlet/outlet porting (machined/plugged)
options:
T1 is the top tank port open.
T2B is code for side tank port plugged.
P1B is code for top inlet port plugged.
P2 is code for top inlet port open.
Inlet Cover Portion of Spec Sheet
23
23
PB
I
140
T1
T2B
P1B
P2
STATE:
FILLED BY:
# 1 # 2
pos pos description
12 47 Circuit type
15 50 Spool actuator
16 51 Lever Bracket / handle
17 51C Clevis or Handle location
17C 52 Spool pos. indication
24 60 Spool function
25 62 Piston head side
26 76A Port A valve
27 76B Port B valve
88A Restrictor on port A
88B Restrictor on port B
90 Spacer Section
93 Mid Inlet type
94 Main relief valve
98 Pressure setting (PSI)
98C Relief Flow Setting (GPM)
P/N SECTION
P/N MCH. CAST
SPACER SECTION
MID INLET
Tank connection T2
Pump connection P1
Pump connection P2
Pressure setting (PSI)
Relief Flow Setting (GPM)
Tank connection T1
Type of Inlet
Main relief valve
description
Max. Inlet flow (GPM)
STACK POS
INLET WORK SECTION
[04] CONNECTIONS
THREAD
G= ALL PORTS 3/8" BSP
U= ALL PORTS 9/16" UNF (SAE #6)
U8 = ALL PORTS 3/4" UNF (SAE #8)
U6 = P AND T 3/4" UNF AND WORK PORTS 9/16" UNF
DATE:
CITY:
CUSTOMER
U8
Customer Information
Code Position Reference
Section Number
starting with the Inlet Cover
Ordering Information

11 Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
Valve Assembly – General Information
The VO40 has two basic thread versions - UNF (SAE) or BSP.
[04] – Connections Thread
G3/8 BSP Inlet, Outlet & Work Ports.
U9/16" UNF (SAE-6) Inlet, Outlet & Work Ports.
U6 9/16" UNF (SAE-6) Work Ports, 3/4" UNF (SAE-8) Inlet/Outlet Ports.
U8 3/4" UNF (SAE-8) Inlet, Outlet & Work Ports.
[05] – System Voltage To be determined when the solenoid option is released
[07] – Surface Treatment (Paint)
X No Paint.
PPaint valve black.
[08] – Customer Designated ID: Enter Customer Part Number
Ordering Information

12 Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
The inlet cover of VO40 is available in two versions. One is the standard inlet and the other is an inlet with a sole-
noid pump unloader (in development). The porting location options for the standard inlet are:
1) Top/side – inlet and outlet ports. Any unused ports can be plugged.
2) Top – inlet and outlet ports only.
All inlet bodies have a gage port, that comes plugged. SAE #4 (7/16"x20 UNF thread) or 1/4" BSP.
The coding to specify an inlet cover is accomplished by eight fields, as shown below:
[12] – Max Pump Flow
The pump inlet flow can be selected in LPM or GPM.
[15] – Type of Inlet
IStandard Inlet.
IU Inlet with pump unload, solenoid actuated (in development).
[24] to [27] – Inlet Porting Options
INLET OUTLET
GAGE
TANK TANK
OPEN
CENTER
PARALLEL
PATH
INLET
OUTLET
TANK
OPEN
CENTER
PARALLEL
PATH
INLET
GAGE
1) Standard – Top & Side Inlet/Outlet Ports 2) Standard – Top Inlet/Outlet Ports
Ordering Information – Inlet Cover

13 Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
[16] - Main Relief Options
PS Adjustable main pilot-operated relief.
Adjustment range: 50 to 300 bar (725 to 4300 PSI).
PB Adjustable main pilot-operated relief
(Tamperproof aluminum cap).
Adjustment range: 50 to 300 bar (725 to 4300 PSI).
PN Adjustable main direct-acting relief.
Adjustment range: 60 to 207 bar (900 to 3000 PSI).
PA Adjustable main direct-acting relief
(Tamperproof aluminum cap).
Adjustment range: 60 to 207 bar (900 to 3000 PSI).
YY plug (cavity machined and plugged).
[17] – Pressure Setting – Enter pressure setting (PSI or Bar)
Note: Relief valve code PN and PA max setting is
207 bar (3000 PSI).
[17C] – Relief Flow Setting
Flow in LPM or GPM.
Ordering Information – Inlet Cover

14 Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
The VO40 outlet cover is available in two versions: Standard or with pilot generation and regulation for proportional
solenoid applications.
The standard outlet has two porting configurations available:
1) Top and side outlet ports along with machining for conversion to power-beyond or closed-center.
2) Top outlet only.
The coding to specify an outlet is made by four fields as shown below:
[30] – Type of Outlet
US
Standard.
USP With pilot-pressure generation (to be used on solenoid valves) (in development).
[33] to [35] – Outlet Porting Options
1) Top and Side Oulet Ports 2) Top Oulet Port Only
TANK
OPEN
CENTER
OUTLET
OUTLET
OUTLET
OUTLET
TANK
OPEN
CENTER
Ordering Information – Outlet Cover

15 Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
Power-Beyond Closed-Center
[33] to [35] – Outlet Porting Options
OUTLET
OUTLET
TANK
OPEN
CENTER
POWER
BEYOND
OUTLET
OUTLET
TANK
OPEN
CENTER
CLOSED
CENTER
PLUG
Ordering Information – Outlet Cover

16 Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
The VO40 valve can be supplied in combinations from one to ten work sections. For each work section there is
a variety of spool options, actuators, positioners and port accessories. Work sections can have parallel, series,
and/or tandem circuitry. All types can be combined in the same valve assembly.
All work sections with hold in neutral spools have transition checks (load checks). All work sections with free flow
in neutral spools (motor) do not include transition checks (load checks). Contact Parker if you require a deviation
from this configuration.
Work sections are available with or without work port option machining. Integrated pilot-operated checks (Lock-
Out) are available in a specially machined casting (ordering code on page 20 [76 A/B]). A spacer section which
provides for more spacing between sections is also available (ordering code on page 20 [90]).
Examples of work port machining options:
Section without RV Cavities Section with RV Cavities
Section with PO Checks
The coding to specify a work section is made by 11 fields, as shown below:
[47] – Work Section Circuitry
PParallel Circuitry.
TTandem Circuitry – Provides priority to upstream sections.
SSeries Circuitry– (In development).
The VO40 Pilot-Operated Check (Lock-Out) sections
provide near zero leakage and can prevent cylinder
drift when the spool is in the neutral position. When
the spool is shifted to a power position, oil is directed
to one work port. Return oil is momentarily blocked
until pilot pressure unseats the check (3.1:1 ratio). With
207 bar (3000 PSI) load, it will require 67 bar (968 PSI)
into the opposite work port to unlock.
The spool is a 4-way, 3-position free flow spool which
prevents system pressure leakage from building up
and unlocking the PO checks.
Ordering Information – Work Sections