Functional Safety
Product Reliability Data (MTTF) for
H1P069-280
www.danfoss.com
Functional Safety
H1 Pumps 069-280 Product Reliability Data
Revision history Table of revisions
Date Changed Rev
April 2021 Changed document number from '70086000' to 'AB159286485026' and added H1 280
information
May 2015 Added CCO information CB
April 2014 Danfoss layout CA
May 2013 Revise Functions - EC1035798 B
August 2012 First edition - EC1014364 A
0204
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Functional Safety
H1 Pumps 069-280 Product Reliability Data
Contents
Reliability Data (MTTF)
Danfoss Component
H1 Pumps............................................................................................................................................................................................ 5
Intended Use......................................................................................................................................................................................5
Introduction........................................................................................................................................................................................5
Results...................................................................................................................................................................................................5
Mission Time.......................................................................................................................................................................................6
Standards and Assumptions
Standards.............................................................................................................................................................................................7
Criteria.............................................................................................................................................................................................7
Component Information and Calculations
MTTFd Individual Pump Functions.............................................................................................................................................8
F1: Safe Controllability (Pump at Demanded Displacement)...........................................................................................8
F2: Safe Stop (Pump to Neutral)..................................................................................................................................................9
F3: Prevent Unexpected Movement....................................................................................................................................... 10
F4: CCO Function............................................................................................................................................................................10
F5: Safe Start.................................................................................................................................................................................... 10
F6: Safe/Correct Direction of Rotation/Movement (Hydraulic Motor/Cylinder)..................................................... 11
References
List of References........................................................................................................................................................................... 12
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Functional Safety
H1 Pumps 069-280 Product Reliability Data
Reliability Data (MTTF)
Transfer of Mean Time to Failure (MTTF) data for the given product from Danfoss to the appropriate party.
This Mean Time to Failure (MTTF) data has been compiled by the Business Area engineering team
responsible. These are professionals at Danfoss, who have the authority and technical knowledge to
calculate the MTTF Data for this product based on the standards set in place by both the industry and/or
Danfoss.
The purpose of this document is to assist in the transfer of MTTF data for the given product from Danfoss
to the appropriate party in a way which will result in a clear understanding and documentation on how
we derived it.
This MTTF data is provided to assist in calculating the overall MTTF of a complete or partially complete
piece of machinery. Danfoss cannot be held responsible for the suitability of these calculated MTTF
values for use in the calculation of the overall machinery MTTF values.
The MTTF values are based on a specific machine use, operating environment, and/or duty cycle as stated
by the standards set in place by both the industry and/or Danfoss.
This communication along with any attached Danfoss drawings, sketches, or data is transmitted in
confidence. No information stated in this document or any attachments or supplements may be
reproduced or disclosed in whole or in part without written permission of Danfoss. Further, neither these
documents nor any attachments are a warranty of any sort by Danfoss or a guarantee of machine
suitability for its intended purpose. It remains the responsibility of the machine manufacturer to ensure
overall machine functionality and overall machine safety.
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Functional Safety
H1 Pumps 069-280 Product Reliability Data
Danfoss Component
H1 Pumps
The H1 family of closed circuit variable displacement axial piston pumps is designed for use with all
existing Danfoss hydraulic motors for the control and transfer of hydraulic power. H1 pumps are compact
and high power density where all units utilize an integral electro-hydraulic servo piston assembly that
controls the rate (speed) and direction of the hydraulic flow. H1 pumps are specifically compatible with
the Danfoss family of PLUS+1 microcontrollers for easy Plug-and-Perform installation.
H1 pumps can be used together in combination with other Danfoss pumps and motors in the overall
hydraulic system. Danfoss hydrostatic products are designed with many different displacement, pressure
and load-life capabilities. Go to the Danfoss Power Solutions website or applicable product catalog to
choose the components that are right for your complete closed circuit hydraulic system.
Intended Use
The H1 axial piston variable displacement pumps are of cradle swash plate design and are intended for
closed circuit applications. The flow rate is proportional to the pump input speed and displacement. The
latter is infinitely adjustable between zero and maximum displacement. Flow direction is reversed by
tilting the swash plate to the opposite side of the neutral (zero displacement) position.
Details regarding intended use, such as application examples and operating conditions, are available in
Technical Information documents on our Danfoss Power Solutions web site.
For any intended use other than the above, contact your local Danfoss representative for advice.
Introduction
Results
This technical report states the MTTFd for a H1 pump configuration. The pump configuration is
discriminated between a pump with feedback system and without a feedback system. The calculation of
the MTTFd values of each function is described in the chapter Component Information and Calculations on
page 8.
The following table shows the MTTFd values of pump configurations and special functions.
Results of MTTFd on pump level
ID Pump Configuration MTTFd [years]
1 EDC Pump 150
2 NFPE, AC, FNR, FDC Pumps 150
3 CCO Function
*
No failures have occurred
*
150
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Functional Safety
H1 Pumps 069-280 Product Reliability Data
Danfoss Component
Mission Time
Definition
Mission time represents the maximum period of time for which a subsystem (or system) can be used
•
After this time it must be replaced
•
The safety system designer must consider the mission time of the components to determine the
•
mission time of each safety function
The mission time of the above mentioned component is 20 years unless otherwise explicitly stated.
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Functional Safety
H1 Pumps 069-280 Product Reliability Data
Standards and Assumptions
Standards
The calculations are performed with reference to the Danfoss Global Standard GS-0078. The standard
GS-0078 defines the following options for how to determine the MTTF/MTTFd value for a specific
component or product.
Criteria
The process and algorithm depends on multiple factors, including:
•
Whether the component is purchased or manufactured
•
The availability of Danfoss field usage history
•
The availability of industry standard field usage history (primarily for electronic components)
•
Similarity of design to existing products
•
Knowledge of the design process
Calculation options:
•
The methods outlined in ISO 13849-1 2006 Annexes C and D
•
Comparison to similar products already in production
•
Industry MTTF databases for widely available components (i.e. electronics)
MIL-HDBK-217
‒
Siemens SN29500
‒
Manufacturer’s Information
‒
•
MTBF data from Verification testing in PDLP
•
Danfoss design practices and procedures for hardware and software design
•
Defects data from Danfoss CQAR database and/or customer data
•
Information on sold products originates from Danfoss SAP
•
Information on application profiles originates from Danfoss technical support knowledge
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Functional Safety
H1 Pumps 069-280 Product Reliability Data
Component Information and Calculations
MTTFd Individual Pump Functions
The following table lists the MTTFd for each individual pump function. Please consult your Danfoss
representative for further understanding of functions and the MTTFd values.
MTTFd for H1 Pumps
ID Function Specification/performance Input Output MTTF
F1 Provide controlled
output flow
F2 Provide hydraulic
braking power
F3 No unintended
movement of
machine without
input signal
F4 CCO function
(decelerating the
vehicle to 0 m/s)
F5 Safe Start See TI manual for specification/
F6 Safe/correct direction
of rotation/
movement (hydraulic
motor/cylinder)
*
Customer is responsible for correct port selection due to input signal
See TI manual for specification/
performance of function
See TI manual for specification/
performance of function
See TI manual for specification/
performance of function
See TI manual for specification/
performance of function
performance of function and
boundries shown in Safe Start
chapter
See TI manual for specification/
performance of function and
boundries shown in Safe/Correct
direction of rotation chapter
Current to
control
Increased flow Seal increase
No input No system
When deenergizing C3
Current C1/C2 No system
Force or current
on selected port
System flow
A/B
pressure
flow A/B
No system
flow A/B
flow A/B
Flow out of
selected port
[years]
150
150
150
150
150
N/A
d
*
F1: Safe Controllability (Pump at Demanded Displacement)
An input signal on the control solenoids C1 and C2 will lead to a proportional system flow A/B of the
hydraulic pump. The following table describes the failures and failed parts that can lead to a failure of the
function.
Detailed boundaries to prevent this failure mode:
•
Controls: EDC, NFPE, FDC (Input current is either constant or changes according to the defined
ramps).
•
Control: FNR (Input current/voltage are either switched on or off)
•
Controls: MDC (Provide controlled and limited rotation of MDC input shaft, torque within specified
torque limits). Pump displacement is directly proportional to the MDC input shaft rotation.
•
Controls: AC-1, AC-2:
o Provide demanded displacement signal. Stroking times are controlled by selected ramp time
parameters.
o All AC parameters are set correctly as found with the prototype machine
•
With negative load (e.g. downhill condition), the engine / prime mover needs to have sufficient
braking torque
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Functional Safety
H1 Pumps 069-280 Product Reliability Data
Component Information and Calculations
Loss of F1 Function Description
Failure Failed Part Description
Not returning to neutral Swash plate bearing Pump does not move to neutral
Broken connection servo system to
swash plate
High servo pressure differential due
to leakage
F2: Safe Stop (Pump to Neutral)
Sticky servo piston
Sticky PL-Valve
Sticky control spool/solenoid
Swash plate Flow of the unit cannot be controlled
Servo piston assembly
Servo cylinder assembly Pump does not move to neutral
Tycon glide ring
Housing crack at servo bores
Control gasket
Loss of solenoid
Hydraulic pressure up to the high pressure relief valve setting is sealed by the pump. The following table
describes the failures and failed parts that can lead to a failure of the function.
Detailed boundaries to prevent this failure mode:
•
Controls: EDC, NFPE (Input current is ramped down below application dependent threshold)
•
Control: FNR (Input current/voltage switched off)
•
Controls: MDC (Provide controlled and limited rotation of MDC input shaft towards neutral). Pump
displacement is directly proportional to the MDC input shaft rotation.
•
Controls: CCO part of NFPE, EDC or MDC (Input current/voltage is switched off, additionally apply
neutral signal to NFPE, EDC or MDC)
•
Control: FDC (Apply ramped current up or down to neutral current as specified in technical
information)
•
Controls: AC-1, AC-2:
o Provide requested displacement signal for neutral and / or deselect current high pressure port
o All AC parameters are set correctly as found with the prototype machine
•
Provide proper timing between park or holding brake engagement and displacement command
according to the application needs
•
Engine / prime mover has sufficient braking torque
Loss of F2 Function Description
Failure Failed Parts Description
Block Lift Cylinder roller bearing These failures decrease the block lift
Snap ring
Valve plate
Retaining spring
System pressure not sealed Sticky check/high pressure valve The high pressure loop is bypassed so
Cylinder block
Valve plate
End cap (high pressure core)
speed. It means the block lift will
occur at lower speeds than maximum
allowed speed.
no flow is backed up to create
braking pressure.
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Functional Safety
H1 Pumps 069-280 Product Reliability Data
Component Information and Calculations
F3: Prevent Unexpected Movement
Without an input to the control, the pump must not create a system flow A/B. The following table
describes the failures and failed parts that can lead to a failure of the function.
Detailed boundaries to prevent this failure mode:
• Controls: EDC, NFPE, FNR (Input current for pump is zero)
• Control: FDC (Apply neutral current as specified in technical information)
• Controls: AC-1, AC-2 (No displacement requested)
• Controls: MDC (No force on MDC lever)
• Machine is stand still (zero vehicle speed)
• No differential pressure (machine is e.g. standing on incline); Park brake recommended
• Pump speed zero to max speed
Loss of F3 Function Description
Failure Failed Part Description
Breakage in feedback system (only
EDC)
High servo pressure differential Loss of solenoid High servo pressure difference due to
Feedback link spring Loss of hydraulic neutral position,
Feedback link
Excenter
Feedback link
Control gasket
free movement of control spool
leakage of one servo cylinder to a
lower pressure level
F4: CCO Function
F5: Safe Start
When the CCO solenoid is de-energized, the pressure supply to the control is blocked and the pump
returns to a safe state where no output flow of the pump is being created.
Loss of F4 Function Description
Failure Failed part Description
No short circuit of servo pressures
after de-energizing of CCO solenoid
Sticky solenoid No short circuit between both servo
Sticky spool
cylinders. No spring force that
swashes the pump back to neutral.
For the pump, this failure is equal to F1: Safe Controllability. The boundaries for the customer are
different. An input signal on the control solenoids C1 and C2 will lead to a proportional system flow A/B
of the hydraulic pump. The following table describes the failures and failed parts that can lead to a failure
of the function.
Detailed boundaries to prevent this failure mode:
•
Controls: EDC, NFPE (Input current is ramped from below threshold)
•
Control: FNR (Input current/voltage is switched on from neutral)
•
Control: FDC (Apply neutral current as specified in technical information)
•
Controls: AC-1, AC-2
o Select requested mode (1, 2, 3, or 4)
o Provide requested displacement signal
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Functional Safety
H1 Pumps 069-280 Product Reliability Data
Component Information and Calculations
o All AC parameters are set correctly as found with the prototype machine
•
Controls: MDC (Provide controlled and limited rotation of MDC input shaft, torque within specified
torque limits)
•
Provide proper timing between park or holding brake release and displacement command according
to the application needs
Loss of F5 Function Description
Failure Failed part Description
Not returning to neutral Swash plate bearing Pump does not move to neutral
Broken connection servo system to
swash plate
High servo pressure differential due
to leakage
Sticky servo piston
Sticky PL-Valve
Sticky control spool/solenoid
Swash plate Flow of the unit cannot be controlled
Swash piston assembly
Servo cylinder assembly Pump does not move to neutral
Tycon glide ring
Housing crack at servo bores
Control gasket
Loss of solenoid
F6: Safe/Correct Direction of Rotation/Movement (Hydraulic Motor/Cylinder)
This failure can only be influenced by the customer. An example is the wrong wiring of control solenoids,
so the vehicle would drive in the opposite direction as expected. Or wrong outputs that are depending in
the software on the controller.
Detailed boundaries to prevent this failure mode:
•
Controls: EDC, NFPE (Input current is provided to the correct connector / solenoid)
•
Control: FDC (Apply ramped current up or down as specified in technical information)
•
Control: FNR (Input current / voltage is provided to the correct connector / solenoid)
•
Controls: MDC (Provide controlled and limited rotation of MDC input shaft in the correct direction,
torque within specified torque limits). Pump displacement is directly proportional to the MDC input
shaft rotation.
•
Controls: AC-1, AC-2
o Provide correct direction signal (FNR)
o AC output current is provided to the correct connector/solenoid
o All AC parameters are set correctly as found with the prototype machine
•
With negative load (e.g. downhill condition), the engine/prime mover needs to have sufficient
braking torque
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Functional Safety
H1 Pumps 069-280 Product Reliability Data
References
List of References
These documents provide design theory and detailed calculations for building hydraulically powered
machines.
•
ISO 13849-1,2 Safety of machinery – Safety-related parts of control systems; ISO13839-1:2006,
ISO13849-2:2003
•
BC152886483968 H1 Axial Piston Pumps, Single and Tandem Basic Information
•
H1 pumps product page
12 | © Danfoss | April 2021 AB159286485026en-000204
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 (US) Company
2800 East 13th Street
Ames, IA 50010, USA
Phone: +1 515 239 6000
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
Products we offer:
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•
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•
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•
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•
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•
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•
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•
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•
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•
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•
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•
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•
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•
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Telematics
•
Danfoss Power Solutions is a global manufacturer and supplier of high-quality hydraulic and
electric 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 the
marine sector. Building on our extensive applications expertise, we work closely with you to
ensure exceptional performance for a broad range of applications. We help you and other
customers around the world speed up system development, reduce costs and bring vehicles
and vessels to market faster.
Danfoss Power Solutions – your strongest partner in mobile hydraulics and mobile
electrification.
Go to www.danfoss.com for further product information.
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