Bosch Rexroth 31 Series User manual

Instruction manual
RE 92701-01-B/04.2018
Replaces: 01.2012
English
Axial piston variable pump
A10VO, A10VSO
Series 31

© Bosch Rexroth AG 2018. All rights reserved,
also regarding any disposal, exploitation,
reproduction, editing, distribution, as well
as in the event of applications for industrial
property rights.
The data specified within only serves
to describe the product. No statements
concerning a certain condition or suitability
for a certain application can be derived from
our information. The information given does
not release the user from the obligation of
own judgment and verification. It must be
remembered that our products are subject
to a natural process of wear and aging.
The cover shows an example application.
The product delivered may differ from the
image on the cover.
The original instruction manual was created in
the German language.

Contents 3/60
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1 About this documentation 5
1.1 Validity of the documentation 5
1.2 Required and supplementary documentation 5
1.3 Representation of information 6
1.3.1 Safety instructions 6
1.3.2 Symbols 7
1.3.3 Designations 8
1.3.4 Abbreviations 8
2 Safety instructions 9
2.1 About this chapter 9
2.2 Intended use 9
2.3 Improper use 9
2.4 Personnel qualifications 10
2.5 General safety instructions 11
2.6 Product-specific safety instructions 12
2.7 Personal protective equipment 14
3 General notices regarding property and product damage 15
4 Scope of delivery 18
5 About this product 19
5.1 Performance description 19
5.2 Product description 19
5.2.1 Axial piston unit layout 19
5.2.2 Functional description 20
5.3 Product identification 21
6 Transport and storage 22
6.1 Transporting the axial piston unit 22
6.1.1 Transporting by hand 22
6.1.2 Transporting with a lifting device 22
6.2 Storing the axial piston unit 24
7 Installation 26
7.1 Unpacking 26
7.2 Installation conditions 26
7.3 Installation position 27
7.3.1 Below-reservoir installation (standard) 27
7.3.2 Inside-reservoir installation 28
7.3.3 Above-reservoir installation 30
7.4 Installing the axial piston unit 31
7.4.1 Preparation 31
7.4.2 Dimensions 31
7.4.3 General instructions 31
7.4.4 Installation with a coupling 32
7.4.5 Installation on a gearbox 33
7.4.6 Installation with cardan shaft 33
7.4.7 Remove the spacer (for version with through drive) 34
Contents

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7.4.8 Completing installation 35
7.4.9 Hydraulically connecting the axial piston unit 36
7.4.10 Electrically connecting the axial piston unit 41
7.5 Performing flushing cycle 42
8 Commissioning 43
8.1 Initial commissioning 43
8.1.1 Filling the axial piston unit 43
8.1.2 Testing the hydraulic fluid supply 44
8.1.3 Performing a functional test 45
8.2 Running-in phase 45
8.3 Recommissioning after standstill 46
9 Operation 47
10 Maintenance and repair 47
10.1 Cleaning and care 47
10.2 Inspection 48
10.3 Maintenance 48
10.4 Repair 49
10.5 Spare parts 49
11 Removal and replacement 50
11.1 Required tools 50
11.2 Preparing for removal 50
11.3 Removal 50
11.4 Preparing components for storage or further use 50
12 Disposal 51
13 Extension and conversion 51
14 Troubleshooting 52
14.1 How to proceed for troubleshooting 52
14.2 Malfunction table 53
15 Technical data 57
16 Alphabetical index 58
Contents

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1 About this documentation
1.1 Validity of the documentation
This documentation applies to the following products:
•Axial piston variable pump A10VO Series 31
•Axial piston variable pump A10VSO Series 31
This documentation is intended for machine/system manufacturers, assemblers and
service engineers.
It contains important information on the safe and appropriate transport, installation,
commissioning, operation, maintenance, removal and simple troubleshooting of the
axial piston unit.
▶ Read this manual completely, in particular chapter 2 “Safety instructions” on
page 9 and chapter 3 “General notices regarding property and product
damage” on page 15 before you start work with the axial piston unit.
1.2 Required and supplementary documentation
▶ Only commission the axial piston unit if the documentation marked with the book
symbol is available to you and you have understood and observed it.
Table 1: Required and supplementary documentation
Title Document number Document type
Order confirmation
Contains the order-related technical data of your axial piston variable pump
A10VO or A10VSO.
– Order confirmation
Installation drawing
Contains the outer dimensions, all connections and the hydraulic circuit diagram
for your axial piston variable pump A10VO or A10VSO.
Please request the
installation drawing
from your contact at
Bosch Rexroth.
Installation drawing
Axial piston variable pump A10V(S)O,
size 18 (A10VSO),
size 28 to 140 (A10VO)
Contains the permissible technical data.
92701 Data sheet
Axial piston variable pump A10VSO, size 18 to 140
Contains the permissible technical data.
92711 Data sheet
Hydraulic fluids based on mineral oils and related hydrocarbons
Describes the requirements on a hydraulic fluid based on mineral oil and related
hydrocarbons for operation with Rexroth hydraulic components, and assists you in
selecting a hydraulic fluid for your system.
90220 Data sheet
Environmentally acceptable hydraulic fluids
Describes the requirements on an environmentally acceptable hydraulic fluid
for operation with Rexroth hydraulic components and assists you in selecting a
hydraulic fluid for your hydraulic system.
90221 Data sheet
Fire-resistant, water-free hydraulic fluids (HFDR/HFDU)
Describes the requirements on fire-resistant, anhydrous hydraulic fluids
(HFDR/HFDU) for operation with Rexroth hydraulic components and assists you in
selecting a hydraulic fluid for your hydraulic system.
90222 Data sheet
Fire-resistant hydraulic fluids – hydrous (HFAE, HFAS, HFB, HFC)
Describes the requirements on fire-resistant, hydrous hydraulic fluids
(HFAE, HFAS, HFB, HFC) for operation with Rexroth hydraulic components and
assists you in selecting a hydraulic fluid for your hydraulic system.
90223 Data sheet

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Table 1: Required and supplementary documentation
Title Document number Document type
Axial piston units for operation with fire-resistant hydraulic fluids – anhydrous
and hydrous (HFDR, HFDU, HFA, HFB, HFC)
Describes the requirements on fire-resistant, anhydrous and hydrous
hydraulicfluids (HFDR, HFDU, HFA, HFB, HFC) and contains the technical data for
operation with Rexroth hydraulic components.
90225 Data sheet
Information on the use of hydrostatic drives at low temperatures
Contains additional information on the use of Rexroth axial piston units at low
temperatures.
90300-03-B Manual
Storage and preservation of axial piston units
Contains additional information on storage and preservation.
90312 Data sheet
Axial piston variable pump A10V(S)O, A10VO series 3x and 5x with electro-
proportional differential pressure control EF
92709 Data sheet
Pressure relief valve, direct controlled 25402 Data sheet
Proportional pressure relief valve 29166 Data sheet
Pump safety block 25880 Data sheet
Pump safety block 25891 Data sheet
Pressure and flow control system 30030 Data sheet
1.3 Representation of information
Standardized safety instructions, symbols, terms and abbreviations are used
throughout this documentation so that you can work quickly and safely with your
product. For clarification, they are explained in the sections below.
1.3.1 Safety instructions
This manual contains safety instructions in chapter 2.6 “Product-specific safety
instructions” on page 12 and in chapter 3 “General notices regarding property
and product damage” on page 15, as well as before a sequence of actions or an
instruction for action involving a risk of personal injury or property damage.
Always follow the instructions on avoiding the dangers associated with the use of
this product.
Safety instructions are set out as follows:
SIGNAL WORD
Type and source of danger!
Consequences of noncompliance
▶ Measures to prevent danger
•Warning sign: draws attention to the danger
•Signal word: identifies the degree of the danger
•Type and source of danger: indicates the type and source of the danger
•Consequences: describes what occurs if safety instructions are disregarded
•Precautions: states how the danger can be avoided

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Table 2: Danger classes as defined in ANSI Z535.6
Warning sign, signal word Meaning
DANGER Identifies a dangerous situation that will result in death or
serious injury if it is not avoided.
WARNING Identifies a dangerous situation that may result in death or
serious injury if it is not avoided.
CAUTION Identifies a dangerous situation that may result in minor to
moderate injury if it is not avoided.
NOTICE Property damage: The product or surrounding area may be
damaged.
1.3.2 Symbols
The following symbols indicate information that is not safety-relevant but increases
understanding of the documentation.
Table 3: Meaning of symbols
Symbol Meaning
If this information is disregarded, the product cannot be used and/or
operated to its full extent.
▶ Single, independent action
1.
2.
3.
Numbered instruction:
The numbers indicate that the actions must be completed in order.

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1.3.3 Designations
This documentation uses the following designations:
Table 4: Designations
Designation Meaning
A10VO Axial piston variable pump, open circuit, maximum pressure 350 bar,
for mobile applications
A10VSO Axial piston variable pump, open circuit, maximum pressure 350 bar,
for stationary applications
Threaded plug Metal screw, pressure-resistant
Protective plug Made out of plastic, not pressure-resistant, only for transportation
As an umbrella term for “axial piston variable pump A10VO” and/or “A10VSO” the
designation “axial piston unit” is used in the following.
1.3.4 Abbreviations
This documentation uses the following abbreviations:
Table 5: Abbreviations
Abbreviation Meaning
ATEX EC directive on explosion protection (Atmosphère explosible)
DG Two-point control, directly controlled
DFLR Pressure flow power controller
DFR/DFR1/DRSC Pressure flow controller
DIN Deutsches Institut für Normung (German Institute for Standardization)
DRG Pressure controller, remotely controlled
EF Electro-proportional differential pressure control
ISO International Organization for Standardization
JIS Japan Industrial Standard
RE Rexroth document in the English language
VDI2230 Directive for the systematic calculation of high duty screwed joints and
cylindrical screw joints from the VDI (Verein Deutscher Ingenieure -
Association of German Engineers)

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2 Safety instructions
2.1 About this chapter
The axial piston unit has been manufactured to generally accepted engineering
standards. There is still, however, a risk of personal injury or property damage if this
chapter and the safety instructions in this documentation are not observed.
▶ Read this documentation completely and thoroughly before working with the axial
piston unit.
▶ Keep it in a location where it is accessible to all users at all times.
▶ Always include the required documentation when you pass the axial piston unit
on to third parties.
2.2 Intended use
Axial piston units are hydraulic components, meaning that in their application
area they are classified neither as complete nor as partly completed machinery as
defined in the EC Machinery Directive 2006/42/EC. The component is exclusively
intended to form partly completed machinery or complete machinery together with
other components. The component should only be commissioned after it has been
installed in the machine/system for which it is intended and the safety of the entire
system has been established in accordance with the Machinery Directive.
This product is intended for the following use:
The axial piston unit is only approved as a pump for hydrostatic drives in an open
circuit.
▶ Observe the technical data, application and operating conditions and
performance limits as specified in data sheet 92701 and 92711 and in the order
confirmation. Information about approved hydraulic fluids can be found in data
sheet 92701 and 92711.
The axial piston unit is only intended for commercial use and not for private use.
Intended use includes having fully read and understood this manual, especially
chapter 2 “Safety instructions” on page 9.
2.3 Improper use
Any use other than that described as intended use is considered improper.
Bosch Rexroth AG is not liable for damages resulting from improper use. The user is
solely responsible for any risks arising from improper use.
The following foreseeable misuses are also considered improper (this list is not
exhaustive):
•Use outside the operating parameters approved in the data sheet or in the order
confirmation (unless specifically approved by the customer)
•Use of non-approved fluids, e.g. water or polyurethane components
•Changes to factory settings by unauthorized persons
•Use of assembled parts (e.g. attachment filter, control unit, valves) other than the
specified Rexroth components
•Use of the axial piston unit with assembled parts under water at a depth of
more than 10meters without the necessary additional measures, e.g. pressure
equalization. Units with electrical components (e.g. sensors) generally cannot

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come into contact with water. Axial piston units may only be used on a case-to-case
basis for this application.
•The maximum permissible case pressure specified in the data sheet must not be
exceeded.
•Use of the axial piston unit in explosive environments unless the component or
machine/system has been certified as compliant with the ATEX Directive 2014/34/EU
•Use of the axial piston unit in a corrosive atmosphere
•Use of the axial piston unit in aircraft or spacecraft
2.4 Personnel qualifications
The activities described in this manual require a basic understanding of mechanics,
electricity and hydraulics, as well as familiarity with associated technical terms.
For transporting and handling the product, additional familiarity with the use of
lifting devices and lifting accessories is required. In order to ensure safe use, these
activities should only be performed by skilled personnel or an instructed person
under the direction and supervision of skilled personnel.
Skilled personnel refers to persons who possess the professional training,
knowledge and experience, as well as the understanding of the regulations relevant
to the work to be done that are necessary to recognize possible hazards and take
the appropriate safety measures. Skilled personnel must follow the rules relevant to
their field and have the necessary hydraulics expert knowledge.
Expertise in hydraulics includes:
•Being able to read and fully understand hydraulic circuit diagrams
•In particular, fully understanding the relationships with regard to safety devices
•Understanding how hydraulic components work and are put together.
Bosch Rexroth offers training support for specialized fields. An overview of the
training contents can be found online at: www.boschrexroth.com/training.

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2.5 General safety instructions
•Observe applicable accident prevention and environmental protection regulations.
•Observe the safety regulations of the country in which the product is used/
operated.
•Use Rexroth products only when they are in good working order.
•Observe all notices on the product.
•Do not install, operate, remove or maintain Rexroth products if under the influence
of alcohol, drugs or medication that may affect your reaction time.
•Only use genuine Rexroth accessories and spare parts to ensure there is no risk to
personnel from unsuitable spare parts.
•Observe the technical data and ambient conditions specified in the product
documentation.
•If unsuitable products are installed or used in applications that are of relevance to
safety, unexpected operating conditions may occur in the application, which could
result in personal injury or property damage. For this reason, only use the product
in safety-relevant applications if this use is expressly indicated and approved in
the product documentation, e.g., in explosion protection applications or in safety-
related parts of a control system (functional safety).
•Only commission the product if it has been determined that the end product
(e.g., machinery or system) in which the Rexroth products are installed complies
with the country-specific provisions, safety regulations and standards for the
application.
•Use tools appropriate for the work being performed and wear appropriate
protective clothing to prevent punctures and cuts (e.g. when removing protective
covers, disassembly).
•There is a risk of entanglement when operating the axial piston unit with a bare
shaft end. Check whether or not your machine requires additional safety measures
for your application. If necessary, make sure these are properly implemented.
•Depending on the type of control used, electromagnetic effects can be produced
when using solenoids. The use of the direct current (DC) on the electromagnet
does not produce any electromagnetic interference (EMI), nor is the electromagnet
influenced by EMI. Potential electromagnetic interference (EMI) exists if the
solenoid is energized with a modulated direct current (e.g. PWMsignal). The
machine manufacturer should conduct appropriate tests and take appropriate
measures to ensure that other components or operators (e.g.with a pacemaker)
are not affected by this potentiality.

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2.6 Product-specific safety instructions
The following safety instructions apply to chapters 6 to 14.
WARNING
Danger from excessive pressure!
Risk of death or injury, or property damage!
Improperly changing the factory pressure settings can result in a pressure increase
beyond the max. permissible pressure.
Operating the unit above the max. permissible pressure can cause components to
burst and hydraulic fluid to escape under high pressure.
▶ Changes to the factory settings may only be made by Bosch Rexroth specialists.
▶ In addition, a pressure relief valve is required in the hydraulic system as a back-
up. If the axial piston unit is equipped with a pressure cut-off and/or pressure
controller, this is not an adequate safeguard against pressure overload.
Danger from suspended loads!
Risk of death or injury, or property damage!
Improper transportation may cause the axial piston unit to fall down and lead to
injury, e.g. crushing or fracture, or damage to the product.
▶ Make sure that the load bearing capacity of the lifting device is sufficient to
safely bear the weight of the axial piston unit.
▶ Never stand or reach under suspended loads.
▶ Make sure the unit remains stable during transport.
▶ Wear your personal protective equipment (e.g. safety goggles, safety gloves,
suitable working clothes, safety shoes).
▶ Use suitable lifting devices for transportation.
▶ Observe the prescribed position of the lifting strap.
▶ Observe the national laws and regulations on occupational health and safety,
and transportation.
System/machine under pressure!
Risk of death or serious injury when working on unsecured machines/systems!
Risk of property damage!
▶ Switch off the entire system and secure it against reactivation according to the
parameters provided by the machine/system manufacturer.
▶ Make sure all relevant components in the hydraulic system are depressurized.
Follow the machine/system manufacturer's specifications.
▶ Note that the hydraulic system may still may be under pressure even after the
pressure supply itself has been disconnected.
▶ Do not disconnect any line connections, ports or components as long as the
hydraulic system is under pressure.

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WARNING
Escaping hydraulic fluid mist!
Risk of explosion and fire, health hazard, risk of environmental pollution!
▶ Depressurize the relevant machine/system component and repair the leak.
▶ Only perform welding work when the machine/system is depressurized.
▶ Keep open flames and ignition sources away from the axial piston unit.
▶ If axial piston units are located in the vicinity of ignition sources or powerful
thermal radiators, a shield must be erected to ensure any escaping hydraulic
fluid cannot be ignited, and to protect hose lines from premature aging.
Electrical voltage!
Risk of injury from electric shock or risk of property damage!
▶ Always disconnect the relevant part of the machine/system before installing the
product or when inserting/removing connectors. Protect the machine/system
against being re-energized.
Restriction of control function!
Risk of injury or property damage!
Moving parts in control equipment (e.g.valve spools) can, under certain
circumstances, get stuck in position as a result of contamination (e.g.impure
hydraulic fluid, abrasion, or residual dirt from components). As a result, the
hydraulic fluid flow and the build-up of torque in the axial piston unit can no longer
respond correctly to the operator’s specifications. Even the use of various filter
elements (external or internal flow filtration) will not rule out a fault but merely
reduce the risk.
▶ Check whether your application requires that remedial measures be taken
on your machine in order to bring the driven consumer into a safe position
(e.g. safe stop).
▶ If necessary, make sure these are properly implemented.

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CAUTION
High noise development during operation!
Risk of hearing damage or hearing loss!
The noise emission of axial piston units depends on, among other factors,
rotational speed, working pressure and installation conditions. The sound pressure
level may rise above 70 dB (A) in certain application conditions.
▶ Always wear hearing protection near a running axial piston unit.
Hot surfaces on axial piston unit!
Risk of burning!
▶ Allow the axial piston unit to cool down sufficiently before touching it.
▶ Wear heat-resistant protective clothing, e.g. gloves.
Improper cable and line routing!
Risk of stumbling and property damage! Improper routing of cables and lines
can cause a risk of stumbling as well as damage to equipment and components,
e.g. due to lines and connectors being torn off.
▶ Always lay cables and lines so no one can trip over them, they do not become
kinked or twisted, do not rub on edges and do not run through sharp-edged
ducts without adequate protection.
Contact with hydraulic fluid!
Risk of adverse health effects, e.g. eye injury, skin irritation, poisoning from
inhalation!
▶ Avoid contact with hydraulic fluids.
▶ When working with hydraulic fluids, strictly follow the safety instructions
provided by the lubricant manufacturer.
▶ Wear your personal protective equipment (e.g. safety goggles, safety gloves,
suitable working clothes, safety shoes).
▶ Consult a doctor immediately if hydraulic fluid gets in your eyes or bloodstream,
or is swallowed.
Escaping hydraulic fluid due to leakage from machine/system components!
Risk of burning and risk of injury due to escaping hydraulic fluid jet!
▶ Depressurize the relevant machine/system component and repair the leak.
▶ Never attempt to block or seal the leak or hydraulic fluid jet with a cloth.
Danger from improper handling!
Risk of slipping! Risk of slipping on wet surfaces when climbing on the axial
piston unit.
▶ Never grab or climb onto the axial piston unit.
▶ Check how to safely get on top of the machine/system.
2.7 Personal protective equipment
Personal protective equipment is the responsibility of the user of the axial piston
unit. Observe the safety regulations in your country.
All pieces of personal protective equipment should be intact.

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3 General notices regarding property and
product damage
The following instructions apply to chapters 6 to 14.
NOTICE
Danger from improper handling!
Product can be damaged!
▶ Do not subject the product to improper mechanical loads.
▶ Never grab or climb onto the product.
▶ Do not place/lay any objects on the product.
▶ Do not strike the drive shaft of the axial piston unit.
▶ Do not set/place the axial piston unit on the drive shaft or assembled parts.
▶ Do not strike assembled parts (e.g. sensors or valves).
▶ Do not strike sealing surfaces (e.g. at working ports).
▶ Leave the protective covers on the axial piston unit until you connect the lines.
▶ Disconnect all electrical connectors before arc welding or painting.
▶ Make sure the electronic components (e.g., sensors) do not build up
electrostatic charges (e.g., during painting).
Risk of property damage due to inadequate lubrication!
Product can be damaged or destroyed!
▶ Never operate the axial piston unit with insufficient hydraulic fluid. Specifically,
make sure that the rotary group has sufficient lubrication.
▶ When commissioning a machine/system, make sure that the housing area and
the working lines of the axial piston unit are filled with hydraulic fluid and
remain filled during operation. Avoid air inclusions in the forward drive shaft
bearing, especially with the axial piston unit installed with the drive shaft up.
▶ Check the hydraulic fluid level in the housing regularly and recommission, if
necessary. For above-reservoir installation, the housing may drain out through
the drain line after prolonged standstill periods (air enters through the shaft
seal) or through the working line (gap leakage). This means the bearings are
insufficiently lubricated when the system is turned on.
▶ Make sure the suction line is always filled with hydraulic fluid during
commissioning and operation.
▶ With above-reservoir installation, an axial piston unit must be moved to full
swivel angle after no more than three seconds during commissioning and
recommissioning. Make sure that the axial piston unit really does suck in
hydraulic fluid and build up pressure.
Mixing hydraulic fluids!
Product can be damaged!
▶ Before installation, remove all fluids from the axial piston unit to prevent mixing
with the hydraulic fluid used in the machine/system.
▶ Never mix hydraulic fluids from different manufacturers or different types from
the same manufacturer.

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NOTICE
Contamination of hydraulic fluid!
The cleanliness of the hydraulic fluid has a considerable impact on the cleanliness
and service life of the hydraulic system. Contamination of the hydraulic fluid can
cause premature wear and malfunctions!
▶ Make sure that the working environment at the installation site is completely
free of dust and foreign substances in order to prevent foreign particles, such
as welding beads or metal cuttings, from getting into the hydraulic lines and
causing product wear or malfunctions. The axial piston unit should be clean
when installed.
▶ Use only clean connections, hydraulic lines and assembled parts
(e.g. measuring devices).
▶ Do not allow any contamination into the ports when they are being plugged.
▶ Before commissioning, make sure all hydraulic connections are tight, and all
seals and plug-in connections are installed correctly to ensure they are leak-
proof, and fluids and foreign particles cannot enter into the product.
▶ Use a suitable filter system to filter hydraulic fluid during filling to minimize solid
particle contamination and water in the hydraulic system.
Improper cleaning!
Product can be damaged!
▶ Close all openings with appropriate protective covers in order to prevent
cleaning agents from entering the hydraulic system.
▶ Never use solvents or corrosive cleaning agents. Use only water and, if
necessary, a mild cleaning agent to clean the axial piston unit.
▶ Do not point a high-pressure cleaner at sensitive components, e.g. shaft seal,
electrical connections and components.
▶ Use fiber-free cloths for cleaning.
Environmental pollution due to improper disposal!
Careless disposal of the axial piston unit and its assembled parts, the hydraulic
fluid and the packaging material can cause environmental pollution!
▶ Dispose of the axial piston unit, hydraulic fluid and packaging in accordance
with the regulations in your country.
▶ Dispose of the hydraulic fluid in accordance with the applicable safety data
sheet for the hydraulic fluid.
Danger from chemical or corrosive environmental conditions!
Product can be damaged! If the axial piston unit is exposed to chemical or
corrosive environmental conditions, such as sea water, fertilizer or road salt, it can
result in corrosion or, in extreme cases, malfunction. Hydraulic fluid can escape if
leaks occur.
▶ Take appropriate steps to protect the axial piston unit from chemical or
corrosive environmental conditions.

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NOTICE
Escaping or spilling hydraulic fluid!
Risk of environmental pollution and contamination of ground water!
▶ Always place a drip tray under the axial piston unit when adding and draining
the hydraulic fluid.
▶ Use a suitable binding agent if hydraulic fluid is spilled.
▶ Observe the safety data sheet for the hydraulic fluid and the specifications
provided by the system manufacturer.
Danger from hot components!
Nearby products can be damaged! Components that heat up (e.g. solenoids) can
cause damage to nearby products if they are too close.
▶ When installing the axial piston unit, check the distances to nearby products to
ensure that they are not damaged.
The warranty only applies to the machine as delivered.
The warranty will be voided if the product is incorrectly installed, commissioned or
operated, or if it is used or handled improperly.

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4 Scope of delivery
12
3
21
4
Fig. 1: Axial piston unit A10VSO
The scope of delivery includes the following:
•Axial piston unit as per order confirmation
The following parts come assembled on the unit:
•Protective covers (1)
•Protective/threaded plugs(2)
•For version with through drive, protective cover and mounting bolts (3)
•For version with through drive, spacer (4) made of plastic (serves as transport
protection)

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5 About this product
5.1 Performance description
The axial piston variable pump generates, controls and regulates a hydraulic-fluid
flow. The A10VO is designed for mobile applications such as construction machinery.
The A10VSO is designed for stationary applications such as tooling machines.
Refer to data sheets 92701 and 92711 and the order confirmation for the technical
data, operating conditions and operating limits of the axial piston unit.
5.2 Product description
The A10VO and A10VSO are variable pumps with axial piston rotary group in
swashplate design for hydrostatic drive in an open circuit. Flow is proportional to
drive speed and displacement. The flow can be steplessly changed by controlling the
cradle (14). For axial piston units with swashplate design, the pistons are arranged
axially relative to the drive shaft (1).
In an open circuit, the hydraulic fluid flows from the reservoir to the hydraulic pump
from where it is fed to the consumer, e.g. hydraulic motor.
From the consumer, the hydraulic fluid flows directly back to the reservoir.
5.2.1 Axial piston unit layout
1
2
3
5
6
7
8
9
10
111213
14
4
Fig. 2: Layout of the A10VO/A10VSO
1 Drive shaft
2 Retaining plate
3 Opposed piston
4 Spring
5 High-pressure side
6 Control plate
(distributor plate)
7 Connection plate
8 Suction side
9 Stroking piston
10 Control valve
11 Piston
12 Cylinder
13 Slipper pad
14 Cradle
Open circuit

20/60 About this product
Bosch Rexroth AG, A10VO, A10VSO Series 31, RE 92701-01-B/04.2018
5.2.2 Functional description
Torque and rotational speed are applied to the drive shaft(1) by a drive motor. The
cylinder(12) is picked up and turned by the splines of the drive shaft. With every
revolution, the pistons(11) execute a stroke in the cylinder bores, the size of which
depends on the pitch of the cradle(14). The slipper pads (13) are held on with the
pistons and guided along the glide surface of the cradle by the retaining plate (2).
The swashplate setting during a rotation causes each piston to move over the bottom
and top dead centers and back to its initial position. Here, hydraulic fluid is fed in
and drained out through the two control slots in the control plate(6) according to
the stroke displacement. On the suction side (8) hydraulic fluid flows into the piston
chamber as the piston recedes. At the same time, on the high-pressure side (5) the
fluid is pushed out of the cylinder chamber into the hydraulic system by the pistons.
The swivel angle of the cradle (14) is infinitely variable. Adjusting the swivel angle
changes the piston stroke and, with it, the displacement. The swivel angle is
controlled hydraulically by means of the stroking piston. The swashplate is mounted
in swivel bearings for smooth operation and it is kept in balance by the opposing
piston (3). Increasing the swivel angle increases the displacement; reducing the
angle reduces displacement accordingly.
Various control devices are available depending on requirements. Information
about this can be found in data sheet 92701, 92711 and 92709.
Pump
Control