Danfoss Series 40 Axial Piston Motors Technical Information
Technical Information
Series 40 Axial Piston Motors
powersolutions.danfoss.com
Technical Information
Series 40 Axial Piston Motors
Revision history Table of revisions
Date Changed Rev
February 2017 Corrected document formatting 0703
October 2016 Minor updates 0702
January 2014 Danfoss layout GA
September 2013 add system pressure information FG
June 2013 add anti-cavitation option FF
April 2011 correct system pressure gauge port 7/16-20 FE
August 2010 new back page FD
March 2010 minor edits FC
November 2007 correction to maximum torque rating 15 and 19 tooth FB
April 2007 Revised dimensions for straight keyed shaft FA
September-2006 Corrections in model code examples F
September-2005 Major Revision E
2 | © Danfoss | February 2017 520L0636 | 0703
Technical Information
Series 40 Axial Piston Motors
Contents
General description
Basic design........................................................................................................................................................................................5
Key features........................................................................................................................................................................................ 5
Cross sections.................................................................................................................................................................................... 6
System circuit diagram...................................................................................................................................................................7
M46 motor schematic ....................................................................................................................................................................7
Technical Specifications
Overview..............................................................................................................................................................................................8
General.................................................................................................................................................................................................8
Features and options...................................................................................................................................................................... 8
Specifications.....................................................................................................................................................................................8
Operating parameters.................................................................................................................................................................... 8
Fluid specifications.......................................................................................................................................................................... 9
Hydraulic unit life............................................................................................................................................................................. 9
Performance.......................................................................................................................................................................................9
Bearing life and external shaft loading ................................................................................................................................. 10
Operating Parameters
Fluids.................................................................................................................................................................................................. 12
Viscosity.............................................................................................................................................................................................12
Temperature.................................................................................................................................................................................... 12
Case pressure...................................................................................................................................................................................12
System Pressure..............................................................................................................................................................................13
Speed ratings...................................................................................................................................................................................13
System design parameters
Sizing equations.............................................................................................................................................................................14
Filtration............................................................................................................................................................................................ 14
Bypass valve.....................................................................................................................................................................................14
Loop flushing valve.......................................................................................................................................................................15
Charge Flow.....................................................................................................................................................................................16
Charge Pressure/Open Circuit Operation............................................................................................................................. 16
Redundant braking system requirement..............................................................................................................................16
Reservoir............................................................................................................................................................................................16
Overpressure protection............................................................................................................................................................. 17
Product coding
Revised model code......................................................................................................................................................................18
Model code modules....................................................................................................................................................................18
Fixed motor.................................................................................................................................................................................18
Variable motor...........................................................................................................................................................................18
Features and options
Anti-Cavitation Valve Option.....................................................................................................................................................20
Displacement limiters...................................................................................................................................................................20
Speed sensor option.....................................................................................................................................................................21
Pulse pickup and connector.......................................................................................................................................................23
Shaft options....................................................................................................................................................................................23
Through-shaft options................................................................................................................................................................. 24
Shaft options
M25 MF.............................................................................................................................................................................................. 25
M35/44 MF........................................................................................................................................................................................25
M35/44 MV....................................................................................................................................................................................... 26
M46 MV..............................................................................................................................................................................................27
Control options
Direct displacement control (DDC)......................................................................................................................................... 28
External Control Handle Requirements............................................................................................................................28
Two-position hydraulic control.................................................................................................................................................29
Installation drawings
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Danfoss | February 2017 520L0636 | 0703 | 3
Technical Information
Series 40 Axial Piston Motors
Contents
M25 MF: axial ports, twin ports, loop flushing, speed sensor........................................................................................30
M25 MF: mounting flange.......................................................................................................................................................... 32
M35/M44 MF: mounting flange................................................................................................................................................32
M35/M44 MF: axial ports, twin ports, loop flushing, speed sensor..............................................................................33
M35/M44 MF: radial ports, twin ports, anti-cavitation valve..........................................................................................34
M35/M44 MF: side ports, through shaft.................................................................................................................................35
M35/M44 MV: twin ports.............................................................................................................................................................36
M35/M44 MV: mounting flange, trunnion control............................................................................................................ 37
M46 MV: side ports, loop flushing............................................................................................................................................37
M46 MV: axial ports, loop flushing...........................................................................................................................................39
M46 MV: side ports, thru shaft twin ports, loop flushing.................................................................................................40
M46 MV: mounting flange..........................................................................................................................................................41
M46 MV: control ports..................................................................................................................................................................42
Schematics
Motor Schematics.......................................................................................................................................................................... 43
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Technical Information
Series 40 Axial Piston Motors
General description
Basic design
Series 40 is a family of hydrostatic pumps and motors for medium power applications with maximum
loads of 345 bar [5000 psi]. These pumps and motors can be applied together or combined with other
products in a system to transfer and control hydraulic power.
Series 40 transmissions (pump plus motor) provide an infinitely variable speed range between zero and
maximum in both forward and reverse modes of operation. The pumps and motors each come in four
frame sizes: M25, M35, M44, and M46.
Series 40 pumps are compact, high power density units. All models use the parallel axial piston / slipper
concept in conjunction with a tiltable swashplate to vary the pump’s displacement. Reversing the angle
of the swashplate reverses the flow of fluid from the pump, reversing the direction of rotation of the
motor output.
Series 40 M35, M44, and M46 pumps may include an integral charge pump to provide system
replenishing and cooling fluid flow, as well as servo control fluid flow on M46 pumps. M25 pumps are
designed to receive charge flow from an auxiliary circuit or from a gear pump mounted on the auxiliary
mounting pad. Series 40 pumps feature a range of auxiliary mounting pads to accept auxiliary hydraulic
pumps for use in complementary hydraulic systems.
Series 40 M46 pumps offer proportional controls with either manual, hydraulic, or electronic actuation.
An electric three-position control is also available. The M25, M35, and M44 pumps include a trunnion
style direct displacement control.
Series 40 motors also use the parallel axial piston / slipper design in conjunction with a fixed or tiltable
swashplate. The family includes M25, M35, M44 fixed motor units and M35, M44, M46 variable motor
units.
The M35 and M44 variable motors feature a trunnion style swashplate and direct displacement control.
The M46 variable motors use a cradle swashplate design and a two-position hydraulic servo control.
Key features
3 sizes of variable displacement motors
•
3 sizes of fixed displacement motors
•
Efficient axial piston design
•
Complete family of control systems
•
Proven reliability and performance
•
Compact, lightweight
•
Worldwide sales and service
•
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Danfoss | February 2017 520L0636 | 0703 | 5
Swash plate
Piston
Bearing
Cylinder
Displacement limiter
Cylinder block
Piston
Output shaft
Lip seal
Bearing
Cylinder block
Piston
Output shaft
Lip seal
Bearing
Cylinder block
Piston
Output shaft
Lip seal
Bearing
Servo piston
P101738E
Output shaft
Lip seal
Swash plate
Technical Information
Series 40 Axial Piston Motors
General description
Cross sections
M35/M44 variable motor (MV), M25 fixed motor (MF), M35/M44 fixed motor (MF), M46 variable motor (MV) (SAE flange)
6 | © Danfoss | February 2017 520L0636 | 0703
Input
shaft
Suction flow
Servo pressure
High pressure
Case flow
Charge pressure
Output
shaft
Cylinder
block
assembly
Filter
Charge
pump
Reservoir
Fixed displacement
motor
Cylinder
block
assembly
Heat
exchanger
Check valves
w/ high pressure
relief valve
Variable
displacement
pump
Heat exchanger
bypass
Charge relief
valve
Displacement
control
valve
Control
handle
Bypass
valve
Loop flushing
module
P100586E
M2
B
A
M1
X2
X1
L2
L2
P101869
Technical Information
Series 40 Axial Piston Motors
General description
System circuit diagram
A Series 40 M35 fixed motor is shown in a hydraulic circuit with a Series 40 M46 variable pump. A loop
flushing module is included on the motor. The circuit features suction filtration and heat exchanger.
M46 motor schematic
The system ports (A and B) connect to the high pressure work lines. The motor receives pressurized fluid
in its inlet port and discharges de-energized fluid through the outlet port. Either port can act as inlet or
outlet; flow is bidirectional. System port pressure is gauged through ports M1 and M2. The motor has two
case drains (L1 and L2). The motor may include loop flushing. Loop flushing provides additional cooling
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Danfoss | February 2017 520L0636 | 0703 | 7
and filtration capacity.
Technical Information
Series 40 Axial Piston Motors
Technical Specifications
Overview
Specifications and operating parameters are shown below. Not all hardware options are available for all
configurations. For additional information, see Operating Parameters on page 12, System design
parameters on page 14, Product coding on page 18, Features and options on page 20 and Control
options on page 28.
General
Product Line Series 40 motors
Product Type In-line, axial piston, fixed and variable, positive
Direction of Rotation Clockwise (CW) and counterclockwise (CCW)
Installation Position Discretionary, the housing must be filled with hydraulic
Filtration Configuration Suction or charge pressure filtration
Other System Requirements Independent braking system, circuit overpressure
displacement motors
fluid before operation
protection, suitable reservoir and heat exchanger
Features and options
Model M25 MF M35 MF M44 MF M35 MV M44 MV M46 MV
Type of mounting
Port connections
Output shaft
options
Control options
Loop flushing
Displacement
limiters
Speed sensors
SAE B SAE B SAE B SAE B SAE B SAE B
Twin, Axial Side, Twin, Axial Side, Twin, Axial Twin Twin Side, Twin, Axial
Splined, Tapered Splined, Tapered,
Straight Key
- - - DDC DDC Hyd. 2-pos.
Option Option Option Option Option Option
- - - Option Option Option
Option Option Option - - Option
Splined, Tapered,
Straight Key
Splined Splined Splined, Tapered
Specifications
Model Unit M25MF M35 MF M44 MF M35MV M44MV M46 MV
Model configuration - Fixed Fixed Fixed Variable Variable Variable
Type of mounting - SAE B SAE B SAE B SAE B SAE B SAE B
Displacement cm3/rev [in3/rev] 25 [1.50] 35 [2.14] 44 [2.65] 35 [2.14] 44 [2.65] 46 [2.80]
Weight kg [lbf] 11 [26] 11 [26] 11 [26] 21 [47] 21 [47] 23 [51]
Mass moment of inertia
kg•m2 [slug•ft2] 0.0018
[0.0013]
0.0033
[0.0024]
0.0032
[0.0023]
0.0033
[0.0024]
0.0032
[0.0023]
0.0050 [0.0037]
Operating parameters
Model M25 MF M35 MF M44 MF M35 MV M44 MV M46 MV
Case pressure bar [psi]
Maximum working 1.7 [25]
Maximum 5.2 [75]
Speed limits min-1[rpm]
Rated @ max disp. 4000 3600 3300 3600 3300 4000
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100
80
95
90
85
Efficienc
y -
%
0 25 50 75 100
Speed - % of Rated Speed
Volumetric Efficiency - 170 bar [2500 psi]
Volumetric Efficiency - 345 bar [5000 psi]
Overall Efficiency - 170 bar [2500 psi]
Overall Efficiency - 345 bar [5000 psi]
P100 455E
Technical Information
Series 40 Axial Piston Motors
Technical Specifications
Model M25 MF M35 MF M44 MF M35 MV M44 MV M46 MV
Maximum @ max. disp. 5000 4500 4100 4500 4100 4100
Rated @ min. disp. - - - 4200 3900 4500
Maximum @ min. disp.
System pressure bar [psi]
Maximum working 345 [5000] 380 [5511] 345 [5000] 380 [5511] 345 [5000] 345 [5000]
Maximum 385 [5584] 415 [6019] 415 [6019] 415 [6019] 415 [6019] 385 [5584]
Fluid specifications
Ratings and data are based on operation with premium petroleum-based hydraulic fluids reftaining
oxidation, rust, and foam inhibitors.
Parameter Unit Minimum reftinuous Maximum
Viscosity mm /sec (cSt)
Temperature °C [°F] -40 [-40] 82 [180] 104 [220]
Cleanliness ISO 4406 Class 18/13 or better
Filtration
efficiency
Hydraulic unit life
Hydraulic unit life is the life expectancy of the hydraulic components. Hydraulic unit life is a function of
speed and system pressure; however, system pressure is the dominant operating variable affecting
hydraulic unit life. High pressure, which results from high load, reduces expected life.
It is desirable to have a projected machine duty cycle with percentages of time at various loads and
speeds. Danfoss calculates appropriate design pressure from this information. This method of selecting
operating pressure is recommended whenever duty cycle information is available.
All pressure limits are differential pressures and assume normal charge pressure. Series 40 motors will
meet satisfactory life expectancy if applied within the parameters specified in this bulletin. For more
detailed information on hydraulic unit life see BLN9884 Pressure and Speed Limits.
Performance
This performance graph provides typical volumetric and overall efficiencies for Series 40 motors. These
efficiencies apply for all Series 40 motors at maximum displacement.
Motor performance as a function of operating speed
- - - 5300 4850 5000
[SUS]
suction filtration β
charge filtration β
7 [47] 12-60 [70-278] 1600 [7500]
=75 (β10≥1.5)
35-44
=75 (β10≥10)
15-20
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Danfoss | February 2017 520L0636 | 0703 | 9
5000
0
4000
3000
2000
1000
System Pressur
e
0 25 50 75 100
Speed - % of Rated Speed
psi
345
0
270
210
140
bar
70
80%
85%
88%
89%
8
0
%
85%
88%
89%
P100 456E
Technical Information
Series 40 Axial Piston Motors
Technical Specifications
The performance map provides typical motor overall efficiencies at various operating parameters. These
efficiencies apply for all Series 40 motors at maximum displacement.
Motor performance as a function of operating speed
Bearing life and external shaft loading
Bearing life is a function of speed, pressure and swashplate angle, plus any external loads. Other life
factors include oil type and viscosity.
In vehicle propulsion drives with no external loads, where the speed, pressure, and swashplate angle are
often changing, normal bearing ß10 (90% survival) life will exceed the hydraulic unit life.
In non-propel drives, such as conveyors or fan drives, the operating speed and pressure may be nearly
constant leading to a distinctive duty cycle compared to that of a propulsion drive. In propel applications,
Danfoss recommends a bearing life review.
Series 40 motors are designed with bearings that can accept some incidental external radial and thrust
loads. However, any amount of external load will reduce the expected bearing life.
The allowable radial shaft loads are a function of the load position, the load orientation, and the
operating pressures of the hydraulic unit. All external shaft loads have an effect on bearing life. In motor
applications where external shaft loads cannot be avoided, the impact on bearing life can be minimized
by orienting the load to the 180 degree position (see Direction of external shaft load, next page).
The recommended maximum radial load (Re) is based on an external moment (Me) and the distance (L)
from the mounting flange to the load, (see table at below). The loads in the table reflect a worst case
external load orientation (0 degrees), a continuously applied working pressure of 140 bar (2000 psi), 20
bar (285 psi) charge pressure, 1800 min-1(rpm), and a bearing life (ß10) of 2000 hours. Avoid thrust loads
in either direction.
The recommended maximum allowable radial load is calculated as: Re = Me / L
If continuously applied external radial loads exceed the recommended maximum allowable, or thrust
loads are known to occur, contact Danfoss for an evaluation of unit bearing life. Optional high capacity
bearings are available.
Tapered output shafts or clamp-type couplings are recommended for applications where radial shaft side
loads are present.
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L
Re
F
B
T
P100 453E
0 Re
180 Re
90 Re 270 Re
Axis of swashplate
rotation
End vi
ew
of shaft
P100 454E
Technical Information
Series 40 Axial Piston Motors
Technical Specifications
Shaft loading parameters
R
e
M
e
L Distance from mounting flange to point of load
F
B
T Thrust load
Recommended maximum external shaft moments
Me N•m [lbf•in] 29 [255] 25 [225] 24 [215]
External shaft loads
Maximum radial side load
Maximum external moment
Force of block (applies at center of gravity)
M25 M35/44 M46
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Danfoss | February 2017 520L0636 | 0703 | 11
Direction of external shaft load
W
Technical Information
Series 40 Axial Piston Motors
Operating Parameters
Fluids
Ratings and performance data are based on operating with premium hydraulic fluids containing
oxidation, rust, and foam inhibitors. These include premium turbine oils, API CD engine oils per SAE J183,
M2C33F or G automatic transmission fluids (ATF), Dexron™ II (ATF) meeting Allison™ C-3 or Caterpillar
T0‑2 requirements, and certain specialty agricultural tractor fluids. For more information on hydraulic
fluid selection, see Danfoss publications: 520L0463, Hydraulic Fluids and Lubricants, Technical Information,
and 520L465, Experience with Biodegradable Hydraulic Fluids, Technical Information.
Viscosity
Fluid viscosity limits
Condition mm2/s (cSt) SUS
Minimum 7 47
Continuous 12-60 70-278
Maximum 1600 7500
Maintain fluid viscosity within the continuous range for maximum efficiency and bearing life. Minimum
viscosity should only occur during brief occasions of maximum ambient temperature and severe duty
cycle operation. Maximum viscosity should only occur at cold start: Limit speeds until the system warms
up. See Danfoss publication: 520L0463, Hydraulic Fluids and Lubricants, Technical Information.
™
Temperature
Case pressure
Maintain fluid temperature within the limits shown in the table. Minimum temperature relates to the
physical properties of the component materials. Cold oil will not affect the durability of the motor
components. However, it may affect the ability of the motor to transmit
power. Maximum temperature is based on material properties. Don't exceed it. Measure maximum
temperature at the hottest point in the system. This is usually the case drain.
Ensure fluid temperature and viscosity limits are concurrently satisfied.
Temperature limits
Temperature limits
Minimum
(intermittent, cold start)
Continuous 82.2° C [180° F]
Maximum 104.4° C [220° F]
- 40° C [- 40° F]
Maintain case pressure within the limits shown in the table. Ensure housing is kept filled with hydraulic
fluid.
Case pressure limits
Maximum (continuous) 1.7 bar [25 psi]
Intermittent (cold start) 5.2 bar [75 psi]
Warning
Operating outside of case pressure limits will damage the motor. To minimize this risk, use full size inlet
and case drain plumbing, and limit line lengths.
12 | © Danfoss | February 2017 520L0636 | 0703
W
Technical Information
Series 40 Axial Piston Motors
Operating Parameters
System Pressure
System pressure is the differential pressure between high pressure system ports. It is the dominant
operating variable affecting hydraulic unit life. High system pressure, which results from high load,
reduces expected life. Hydraulic unit life depends on the speed and normal operating, or weighted
average, pressure that can only be determined from a duty cycle analysis.
Application pressure is the high pressure relief or pressure limiter setting normally defined within the
order code of the pump. This is the applied system pressure at which the driveline generates the
maximum calculated pull or torque in the application.
Maximum Working pressure is the highest recommended application pressure. Maximum working
pressure is not intended to be a continuous pressure. Propel systems with application pressures at, or
below, this pressure should yield satisfactory unit life given proper component sizing.
Maximum pressure is the highest allowable application pressure under any circumstance. Application
pressures above maximum working pressure will only be considered with duty cycle analysis and factory
approval.
Minimum low loop pressure must be maintained under all operating conditions to avoid cavitation.
All pressure limits are differential pressures referenced to low loop (charge) pressure. Subtract low loop
pressure from gauge readings to compute the differential.
Speed ratings
The table, Operating parameters on page 8, gives rated and maximum speeds for each displacement. Not
all displacements operate under the same speed limits. Definitions of these speed limits appear below.
Rated speed is the maximum recommended operating speed at full power condition. Operating at or
below this speed should yield satisfactory product life. In vehicle propel applications, maximum motor
speed during unloaded, on-road travel over level ground should not exceed this limit.
Maximum speed is the highest operating speed permitted. Exceeding maximum speed reduces motor
life and can cause loss of hydrostatic power and braking capacity. Never exceed the maximum speed
limit under any operating conditions.
Warning
Unintended vehicle or machine movement hazard
The loss of hydrostatic drive line power, in any mode of operation (forward, neutral, or reverse) may cause
the system to lose hydrostatic braking capacity. You must provide a braking system, redundant to the
hydrostatic transmission, sufficient to stop and hold the vehicle or machine in the event of hydrostatic
drive power loss.
Speed limits
Limit min-1(rpm) M25 MF M35 MF M44 MF M35 MV M44 MV M46 MV
Rated at max. displ. 4000 3600 3300 3600 3300 4000
Maximum at max. displ. 5000 4500 4100 4500 4100 4100
Rated at min. displ. - - - 4200 3900 4500
Maximum at min. displ... - - - 5300 4850 5000
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Danfoss | February 2017 520L0636 | 0703 | 13
Base d on SI units
Input f ow Q = (l/m in)
Outp ut torque M = (N•m)
Outp ut power P = (kW)
Motor spe ed n = (min
-1
(rpm))
Base d on US units
Input f ow Q = (US gal/min)
Outp ut torque M = (lbf•in)
Outp ut power P = (hp)
Motor spe ed n = (min
-1
(rpm))
SI units [US units]
Vg= Displacement per revolut ion cm3/rev [in
3
/rev]
p
O
= Ou tlet pressure bar [psi]
pi= Inlet pressure bar [psi]
∆p = pO– p
i
(system pressure) bar [p si]
n = Spee d min-1(rpm)
ηv= Volumet ric eff ciency
ηm= Mechan ical eff ciency
ηt= Overall eff cie ncy (ηv• ηm)
Variables
V
g
• n
1000 •
η
v
Q • 1000 • η
v
V
g
V
g
• n
231 •
η
v
Vg• ∆p • η
m
20 • π
Q •∆p • η
t
600
Vg• ∆p • η
m
2 • π
Q •∆p • η
t
1714
Q • 231• η
v
V
g
Technical Information
Series 40 Axial Piston Motors
System design parameters
Sizing equations
Use the following equations to compute output power, torque, speed, and input flow. Selecting the right
motor starts with an evaluation of system requirements such as speed and torque. Select a motor that
will transmit the required torque, then select a pump that will meet the flow and pressure requirements
of the motor. For more information on hydrostatic drive selection, refer to Danfoss applications guideline
BLN-9885, Selection of Drive Line Components.
Filtration
To prevent damage to the system, including premature wear, fluid entering the motor must be free of
contaminants. Series 40 motors require system filtration capable of maintaining fluid cleanliness at ISO
4406-1999 class 22/18/13 or better.
Consider these factors when selecting a system filter:
Cleanliness specifications
•
Contaminant ingression rates
•
Flow capacity
•
Desired maintenance interval
•
The filter may be located either on the inlet (suction filtration) or discharge (charge pressure filtration)
side of the charge pump. Series 40 pumps are available with provisions for either suction or charge
pressure filtration to filter the fluid entering the charge circuit (see Loop flushing valve on page 15).
Typically, a filter with a beta ratio of β10 = 1.5 to 2.0 is adequate. However, open circuit systems supplied
from a common reservoir may have considerably higher requirements. Because each system is unique,
only a thorough testing and evaluation program can fully validate the filtration system. For more
Bypass valve
information, see Danfoss publication 520L0467, Design Guidelines for Hydraulic Fluid Cleanliness.
In some applications it is desirable to bypass fluid around the variable displacement pump, for example;
to allow a vehicle to move short distances at low speeds without running the prime mover. This is done
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