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 |
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February 2017 |
Corrected document formatting |
0703 |
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October 2016 |
Minor updates |
0702 |
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January 2014 |
Danfoss layout |
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September 2013 |
add system pressure information |
FG |
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June 2013 |
add anti-cavitation option |
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April 2011 |
correct system pressure gauge port 7/16-20 |
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August 2010 |
new back page |
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March 2010 |
minor edits |
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November 2007 |
correction to maximum torque rating 15 and 19 tooth |
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April 2007 |
Revised dimensions for straight keyed shaft |
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September-2006 |
Corrections in model code examples |
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September-2005 |
Major Revision |
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2 | © Danfoss | February 2017 |
520L0636 | 0703 |
Technical Information |
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Series 40 Axial Piston Motors |
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Contents |
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General description |
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Basic design........................................................................................................................................................................................ |
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Key features........................................................................................................................................................................................ |
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Cross sections.................................................................................................................................................................................... |
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System circuit diagram................................................................................................................................................................... |
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M46 motor schematic .................................................................................................................................................................... |
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Technical Specifications |
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Overview.............................................................................................................................................................................................. |
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General................................................................................................................................................................................................. |
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Features and options...................................................................................................................................................................... |
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Specifications..................................................................................................................................................................................... |
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Operating parameters.................................................................................................................................................................... |
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Fluid specifications.......................................................................................................................................................................... |
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Hydraulic unit life............................................................................................................................................................................. |
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Performance....................................................................................................................................................................................... |
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Bearing life and external shaft loading ................................................................................................................................. |
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Operating Parameters |
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Fluids.................................................................................................................................................................................................. |
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Viscosity............................................................................................................................................................................................. |
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Temperature.................................................................................................................................................................................... |
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Case pressure................................................................................................................................................................................... |
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System Pressure.............................................................................................................................................................................. |
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Speed ratings................................................................................................................................................................................... |
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System design parameters |
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Sizing equations............................................................................................................................................................................. |
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Filtration............................................................................................................................................................................................ |
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Bypass valve..................................................................................................................................................................................... |
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Loop flushing valve....................................................................................................................................................................... |
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Charge Flow..................................................................................................................................................................................... |
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Charge Pressure/Open Circuit Operation............................................................................................................................. |
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Redundant braking system requirement.............................................................................................................................. |
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Reservoir............................................................................................................................................................................................ |
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Overpressure protection............................................................................................................................................................. |
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Product coding |
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Revised model code...................................................................................................................................................................... |
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Model code modules.................................................................................................................................................................... |
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Fixed motor................................................................................................................................................................................. |
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Variable motor........................................................................................................................................................................... |
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Features and options |
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Anti-Cavitation Valve Option..................................................................................................................................................... |
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Displacement limiters................................................................................................................................................................... |
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Speed sensor option..................................................................................................................................................................... |
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Pulse pickup and connector....................................................................................................................................................... |
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Shaft options.................................................................................................................................................................................... |
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Through-shaft options................................................................................................................................................................. |
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Shaft options |
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M25 MF.............................................................................................................................................................................................. |
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M35/44 MF........................................................................................................................................................................................ |
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M35/44 MV....................................................................................................................................................................................... |
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M46 MV.............................................................................................................................................................................................. |
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Control options |
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Direct displacement control (DDC)......................................................................................................................................... |
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External Control Handle Requirements............................................................................................................................ |
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Two-position hydraulic control................................................................................................................................................. |
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Installation drawings |
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© Danfoss | February 2017 |
520L0636 | 0703 | 3 |
Technical Information |
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Series 40 Axial Piston Motors |
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Contents |
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M25 MF: axial ports, twin ports, loop flushing, speed sensor........................................................................................ |
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M25 MF: mounting flange.......................................................................................................................................................... |
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M35/M44 MF: mounting flange................................................................................................................................................ |
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M35/M44 MF: axial ports, twin ports, loop flushing, speed sensor.............................................................................. |
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M35/M44 MF: radial ports, twin ports, anti-cavitation valve.......................................................................................... |
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M35/M44 MF: side ports, through shaft................................................................................................................................. |
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M35/M44 MV: twin ports............................................................................................................................................................. |
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M35/M44 MV: mounting flange, trunnion control............................................................................................................ |
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M46 MV: side ports, loop flushing............................................................................................................................................ |
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M46 MV: axial ports, loop flushing........................................................................................................................................... |
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M46 MV: side ports, thru shaft twin ports, loop flushing................................................................................................. |
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M46 MV: mounting flange.......................................................................................................................................................... |
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M46 MV: control ports.................................................................................................................................................................. |
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Schematics |
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Motor Schematics.......................................................................................................................................................................... |
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4 | © Danfoss | February 2017 |
520L0636 | 0703 |
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
© Danfoss | February 2017 |
520L0636 | 0703 | 5 |
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)
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Displacement limiter |
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Bearing |
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Piston |
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Cylinder |
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Cylinder block |
Output shaft |
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Output shaft
Lip seal
Bearing |
Lip seal |
Piston |
Swash plate |
Piston
Cylinder block
Output shaft |
Piston |
Bearing |
Output shaft |
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Bearing |
Lip seal |
Lip seal |
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Cylinder block |
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Swash plate |
Servo piston |
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P101738E |
6 | © Danfoss | February 2017 |
520L0636 | 0703 |
Technical Information
Series 40 Axial Piston Motors
General description
System circuit diagram
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Heat exchanger |
Reservoir |
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Control |
bypass |
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handle |
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Filter |
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Displacement |
Heat |
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control |
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exchanger |
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valve |
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Fixed displacement |
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motor |
Cylinder |
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Cylinder |
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block |
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block |
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assembly |
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assembly |
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Bypass |
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valve |
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Output |
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Charge |
shaft |
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pump |
Loop flushing |
Input |
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module |
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shaft |
Variable |
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Suction flow |
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displacement |
Check valves |
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pump |
w/ high pressure |
Charge pressure |
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relief valve |
Servo pressure |
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High pressure |
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Case flow |
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P100586E |
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
M1 |
X2 |
X1 |
A 
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L2 |
B |
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M2 |
L2 |
P101869
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 and filtration capacity.
© Danfoss | February 2017 |
520L0636 | 0703 | 7 |
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 |
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Product Type |
In-line, axial piston, fixed and variable, positive |
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displacement motors |
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Direction of Rotation |
Clockwise (CW) and counterclockwise (CCW) |
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Installation Position |
Discretionary, the housing must be filled with hydraulic |
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fluid before operation |
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Filtration Configuration |
Suction or charge pressure filtration |
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Other System Requirements |
Independent braking system, circuit overpressure |
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protection, suitable reservoir and heat exchanger |
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Features and options
Model |
M25 MF |
M35 MF |
M44 MF |
M35 MV |
M44 MV |
M46 MV |
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Type of mounting |
SAE B |
SAE B |
SAE B |
SAE B |
SAE B |
SAE B |
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Port connections |
Twin, Axial |
Side, Twin, Axial |
Side, Twin, Axial |
Twin |
Twin |
Side, Twin, Axial |
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Output shaft |
Splined, Tapered |
Splined, Tapered, |
Splined, Tapered, |
Splined |
Splined |
Splined, Tapered |
options |
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Straight Key |
Straight Key |
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Control options |
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DDC |
DDC |
Hyd. 2-pos. |
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Loop flushing |
Option |
Option |
Option |
Option |
Option |
Option |
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Displacement |
- |
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Option |
Option |
Option |
limiters |
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Speed sensors |
Option |
Option |
Option |
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Option |
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Specifications
Model |
Unit |
M25MF |
M35 MF |
M44 MF |
M35MV |
M44MV |
M46 MV |
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Model configuration |
- |
Fixed |
Fixed |
Fixed |
Variable |
Variable |
Variable |
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Type of mounting |
- |
SAE B |
SAE B |
SAE B |
SAE B |
SAE B |
SAE B |
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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] |
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Mass moment of inertia |
kg•m2 [slug•ft2] |
0.0018 |
0.0033 |
0.0032 |
0.0033 |
0.0032 |
0.0050 [0.0037] |
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[0.0013] |
[0.0024] |
[0.0023] |
[0.0024] |
[0.0023] |
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Operating parameters
Model |
M25 MF |
M35 MF |
M44 MF |
M35 MV |
M44 MV |
M46 MV |
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Case pressure bar [psi] |
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Maximum working |
1.7 [25] |
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Maximum |
5.2 [75] |
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Speed limits min-1[rpm] |
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Rated @ max disp. |
4000 |
3600 |
3300 |
3600 |
3300 |
4000 |
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8 | © Danfoss | February 2017 |
520L0636 | 0703 |
Technical Information
Series 40 Axial Piston Motors
Technical Specifications
Model |
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M25 MF |
M35 MF |
M44 MF |
M35 MV |
M44 MV |
M46 MV |
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Maximum @ max. disp. |
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5000 |
4500 |
4100 |
4500 |
4100 |
4100 |
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Rated @ min. disp. |
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- |
- |
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4200 |
3900 |
4500 |
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Maximum @ min. disp. |
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- |
- |
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5300 |
4850 |
5000 |
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System pressure bar [psi] |
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Maximum working |
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345 [5000] |
380 [5511] |
345 [5000] |
380 [5511] |
345 [5000] |
345 [5000] |
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Maximum |
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385 [5584] |
415 [6019] |
415 [6019] |
415 [6019] |
415 [6019] |
385 [5584] |
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Fluid specifications |
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Ratings and data are based on operation with premium petroleum-based hydraulic fluids reftaining |
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oxidation, rust, and foam inhibitors. |
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Parameter |
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Unit |
Minimum |
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reftinuous |
Maximum |
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Viscosity |
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mm /sec (cSt) |
7 [47] |
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12-60 [70-278] |
1600 [7500] |
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[SUS] |
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Temperature |
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°C [°F] |
-40 [-40] |
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82 [180] |
104 [220] |
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Cleanliness |
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ISO 4406 Class 18/13 or better |
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Filtration |
suction filtration |
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β35-44=75 (β10≥1.5) |
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efficiency |
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charge filtration |
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β15-20=75 (β10≥10) |
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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
<![endif]>Efficiency - %
100
Volumetric Efficiency - 170 bar [2500 psi]
95
Volumetric Efficiency - 345 bar [5000 psi]
90
Overall Efficiency - 170 bar [2500 psi]
Overall Efficiency - 345 bar [5000 psi]
85
80
0 |
25 |
50 |
75 |
100 |
Speed - % of Rated Speed
P100 455E
© Danfoss | February 2017 |
520L0636 | 0703 | 9 |
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
<![endif]>System Pressure
bar |
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psi |
345 |
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5000 |
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270 4000
210 3000
140 2000
70 1000
0 0
0
% 0 8
85%
88% |
89% |
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89% |
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88% |
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85% |
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80% |
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25 |
50 |
75 |
100 |
Speed - % of Rated Speed |
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P100 456E
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.
10 | © Danfoss | February 2017 |
520L0636 | 0703 |
Technical Information
Series 40 Axial Piston Motors
Technical Specifications
Shaft loading parameters
Re |
Maximum radial side load |
Me |
Maximum external moment |
L |
Distance from mounting flange to point of load |
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FB |
Force of block (applies at center of gravity) |
T |
Thrust load |
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Recommended maximum external shaft moments
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M25 |
M35/44 |
M46 |
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Me N•m [lbf•in] |
29 [255] |
25 [225] |
24 [215] |
External shaft loads
L
FB
Re
T
P100 453E
Direction of external shaft load
0 Re
End view of shaft
90 Re |
270 Re |
Axis of swashplate
rotation
180 Re
P100 454E
© Danfoss | February 2017 |
520L0636 | 0703 | 11 |
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 |
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Continuous |
12-60 |
70-278 |
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Maximum |
1600 |
7500 |
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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
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 |
- 40° C [- 40° F] |
(intermittent, cold start) |
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Continuous |
82.2° C [180° F] |
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Maximum |
104.4° C [220° F] |
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Case pressure
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] |
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Intermittent (cold start) |
5.2 bar [75 psi] |
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W 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 |
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.
W 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 |
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Maximum at max. displ. |
5000 |
4500 |
4100 |
4500 |
4100 |
4100 |
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Rated at min. displ. |
- |
- |
- |
4200 |
3900 |
4500 |
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|
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|
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Maximum at min. displ... |
- |
- |
- |
5300 |
4850 |
5000 |
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© Danfoss | February 2017 |
520L0636 | 0703 | 13 |
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.
Based on SI units
Input f ow Q = |
|
Vg |
• n |
|
(l/min) |
|
1000 • ηv |
||||||
|
|
|||||
Output torque M = |
Vg • |
p • ηm |
(N•m) |
|||
|
20 • π |
|||||
|
|
|
||||
Output power P = |
|
Q • |
p • ηt |
(kW) |
||
|
600 |
|
|
|||
Motor speed n = Q • 1000 • ηv (min-1(rpm))
Vg
Variables SI units [US units]
Based on US units
Input f ow Q = |
|
Vg • n |
|
(US gal/min) |
||
231 • ηv |
||||||
|
|
|||||
Output torque M = |
|
Vg • |
p • ηm |
(lbf•in) |
||
|
|
2 |
• π |
|
||
Output power P = |
|
Q • |
p • ηt |
(hp) |
||
|
1714 |
|
|
|||
Motor speed n = Q • 231• ηv (min-1(rpm))
Vg
Vg |
= |
Displacement per revolution |
cm3/rev [in3/rev] |
pO |
= |
Outlet pressure |
bar [psi] |
pi |
= |
Inlet pressure |
bar [psi] |
p |
= |
pO – pi (system pressure) |
bar [psi] |
n |
= |
Speed |
min-1 (rpm) |
ηv |
= |
Volumetric eff ciency |
|
ηm |
= |
Mechanical eff ciency |
|
ηt |
= |
Overall eff ciency (ηv • ηm) |
|
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 information, see Danfoss publication 520L0467, Design Guidelines for Hydraulic Fluid Cleanliness.
Bypass valve
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
14 | © Danfoss | February 2017 |
520L0636 | 0703 |
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