Technical Information
Series 40 Direct Displacement Pumps
powersolutions.danfoss.com
Technical Information
Series 40 Direct Displacement Pumps
Revision history |
Table of revisions |
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Date |
Changed |
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July 2017 |
Removed outdated images |
0703 |
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January 2017 |
Minor updates |
0702 |
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July 2015 |
Minor edits |
0701 |
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February 2015 |
Danfoss layout |
GA |
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Sep 2013 |
Change system pressure specs |
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Aug 2013 |
Remove M46 from manual |
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Feb 2010 |
Fix Osaka address |
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Jun 2009 |
Remove M25U outline drawing |
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Jul 2008 |
Add plug for Charge pressure construction port |
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Oct 2007 |
Identified A Pad and B Pad as M35 and M44 |
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Jul 2007 |
orrections to table - G factors for sample applications |
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Jun 2006 |
Corrections to maximum flow |
EC |
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May 2006 |
Added an illustration to page 21 |
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2 | © Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 |
Technical Information |
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Series 40 Direct Displacement Pumps |
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Contents |
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Specifications |
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Design Specifications...................................................................................................................................................................... |
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Technical Specifications................................................................................................................................................................. |
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Operating Parameters..................................................................................................................................................................... |
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Options................................................................................................................................................................................................. |
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Fluid Specifications.......................................................................................................................................................................... |
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General Information |
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Series 40 Family of Pumps and Motors..................................................................................................................................... |
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M25 Variable Pump.......................................................................................................................................................................... |
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M35 Variable Pump (M44 is similar)........................................................................................................................................... |
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M35/44 Pump Schematic.............................................................................................................................................................. |
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Features and Options |
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Key Features....................................................................................................................................................................................... |
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Options................................................................................................................................................................................................. |
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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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Charge Pressure.............................................................................................................................................................................. |
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Case Pressure................................................................................................................................................................................... |
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Pressure Ratings............................................................................................................................................................................. |
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Speed Ratings.................................................................................................................................................................................. |
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Inlet Pressure................................................................................................................................................................................... |
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Theoretical Output........................................................................................................................................................................ |
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System Design Parameters |
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Sizing Equations............................................................................................................................................................................. |
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Filtration............................................................................................................................................................................................ |
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Suction filtration....................................................................................................................................................................... |
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Charge filtration........................................................................................................................................................................ |
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Redundant Braking System Requirement............................................................................................................................. |
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Loop Flushing.................................................................................................................................................................................. |
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Reservoir............................................................................................................................................................................................ |
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Case Drain usage for Tandem Pumps..................................................................................................................................... |
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Bearing Life and External Shaft Loading ............................................................................................................................... |
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Hydraulic Unit Life......................................................................................................................................................................... |
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Mounting Flange Loads............................................................................................................................................................... |
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Model Code |
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Model Code...................................................................................................................................................................................... |
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Options |
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Charge Pump................................................................................................................................................................................... |
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Charge Pump Output Flow........................................................................................................................................................ |
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Charge Pump Power Requirements........................................................................................................................................ |
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Charge Relief Valve........................................................................................................................................................................ |
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Charge Check/High Pressure Relief Valve (HPRV).............................................................................................................. |
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Auxiliary Mounting Pads and Auxiliary Pumps................................................................................................................... |
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Shaft Options................................................................................................................................................................................... |
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M25 Variable Pump....................................................................................................................................................................... |
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M25 Tandem Pump....................................................................................................................................................................... |
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M35/44 Variable Pump................................................................................................................................................................ |
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M35/44 Tandem Pump................................................................................................................................................................ |
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Direct Displacement Control (DDC)........................................................................................................................................ |
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External control handle requirements.............................................................................................................................. |
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Installation Drawings |
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M25 Variable Pump....................................................................................................................................................................... |
33 |
M25 Tandem Pump....................................................................................................................................................................... |
35 |
© Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 | 3 |
Technical Information |
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Series 40 Direct Displacement Pumps |
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Contents |
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M35/44 Variable Pump................................................................................................................................................................ |
37 |
M35/44 Tandem Pump................................................................................................................................................................ |
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Performance Data |
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Performance..................................................................................................................................................................................... |
41 |
Schematics |
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Single Pump Schematics............................................................................................................................................................. |
42 |
Tandem Pump Schematics......................................................................................................................................................... |
43 |
4 | © Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 |
Technical Information
Series 40 Direct Displacement Pumps
Product line |
Series 40 Pumps |
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Pump type |
In-line, axial piston, variable, positive displacement pumps |
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Direction rotation |
Clockwise (CW) or counterclockwise (CCW) available |
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Installation position |
Discretionary, the housing must be filled with hydraulic fluid |
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Filtration configuration |
Suction or charge pressure filtration |
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Other system requirements |
Independent braking system, suitable reservoir and heat exchanger |
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Model |
Unit |
M25 PV |
M35 PV |
M44 PV |
M25 PT |
M35 PT |
M44 PT |
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Pump |
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Single variable pump |
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Tandem variable pump |
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configuration |
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Displacement |
cm3/rev |
24.6 [1.50] |
35.0 [2.14] |
43.5 [2.65] |
24.6 x 2 |
35.0 x 2 |
43.5 x 2 |
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[in3/rev] |
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[1.50 x 2] |
[2.14 x 2] |
[2.65 x 2] |
Weight |
kg [lb] |
19 [41.5] |
25 [55] |
25 [55] |
24 [56] |
45 [99] |
45 [99] |
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Mass moment of |
kg·m2 |
0.0018 |
0.0033 |
0.0032 |
0.0037 |
0.0066 |
0.0064 |
inertia |
[slug·ft2] |
[0.0014] |
[0.0024] |
[0.0023] |
[0.0028] |
[0.0048] |
[0.0047] |
Model |
Unit |
M25 PV |
M35 PV |
M44 PV |
M25 PT |
M35 PT |
M44 PT |
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Case pressure |
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Continuous |
bar [psi] |
1.7 [25] |
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Maximum |
bar [psi] |
5.2 [75] |
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Speed limits |
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Rated @ max angle |
min-1 (rpm) |
4000 |
3600 |
3300 |
4000 |
3600 |
3300 |
Maximim @ max angle |
min-1 (rpm) |
5000 |
4500 |
4100 |
5000 |
4500 |
4100 |
Minimum |
min-1 (rpm) |
500 |
500 |
500 |
500 |
500 |
500 |
System pressure |
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Maximum Working |
bar [psi] |
345 |
380 [5511] |
345 |
345 |
380 |
345 |
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[5000] |
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[5000] |
[5000] |
[5511] |
[5000] |
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Maximum |
bar [psi] |
385 |
415 [6019] |
415 |
385 |
415 |
415 |
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[5584] |
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[6019] |
[5584] |
[6019] |
[6019] |
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Theoretical max flow at |
l/min |
100 |
126 |
145 |
100 |
126 |
145 |
rated speed (per pump) |
[US gal/min] |
[26.0] |
[33.4] |
[38.3] |
[26.0] |
[33.4] |
[38.3] |
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Inlet pressure |
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Continuous |
bar absolute |
0.8 [6.3] |
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[in Hg vacuum] |
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Maximum |
bar absolute |
0.7 [9.2] |
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[in Hg vacuum] |
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Model |
Unit |
M25 PV |
M35 PV |
M44 PV |
M25 PT |
M35 PT |
M44 PT |
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Type of mounting |
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SAE B |
SAE B |
SAE B |
SAE B |
SAE B |
SAE B |
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Port connections |
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Twin |
Twin |
Twin |
Twin |
Twin |
Twin |
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© Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 | 5 |
Technical Information
Series 40 Direct Displacement Pumps
Specifications
Model |
Unit |
M25 PV |
M35 PV |
M44 PV |
M25 PT |
M35 PT |
M44 PT |
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Integral charge pump |
cm3/rev |
- |
11.8 |
11.8 |
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16.4 |
16.4 |
(std) |
[in3/rev] |
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[0.72] |
[0.72] |
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[1.00] |
[1.00] |
Charge relief valve |
bar [psi] |
14.0 |
14.0 |
14.0 |
14.0 |
14.0 |
14.0 |
setting |
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[200] |
[200] |
[200] |
[200] |
[200] |
[200] |
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System pressure |
bar [psi] |
140-345 [2030-5000] |
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regulation |
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Displacement limiters |
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- |
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Input shaft option |
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Splined, Tapered, or Straight Key |
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Auxiliary mounting |
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SAE A |
SAE A |
SAE A |
SAE A |
SAE A |
SAE A |
pad |
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SAE B |
SAE B |
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SAE B |
SAE B |
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Control options |
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DDC |
DDC |
DDC |
DDC |
DDC |
DDC |
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Filtration |
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Suction Filtration or Remote Charge Pressure Filtration |
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configuration |
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Parameter |
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Unit |
Minimum |
Continuous |
Maximum |
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Viscosity |
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mm2/sec (cSt) |
7 |
12-60 |
1600 |
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[SUS] |
[47] |
[70-278] |
[7500] |
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Temperature |
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°C [°F] |
-40 [-40] |
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 efficiency |
suction filtration |
β35-44=75 (β10≥1.5) |
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charge filtration |
β15-20=75 (β10≥10) |
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Ratings and data are based on operation with premium petroleum-based hydraulic fluids containing oxidation, rust, and foam inhibitors.
6 | © Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 |
Technical Information
Series 40 Direct Displacement Pumps
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 pump + motor transmissions 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 and M44 pumps may include an integral charge pump to provide system replenishing and cooling fluid flow. 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.
For complete technical information on M46 pumps, refer to M46 Pumps Technical Information, L1001029.
Series 40 motors 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. For complete technical information on Series 40 motors, refer to Series 40 Motors Technical Information, 520L0636.
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.
The M46 variable motor is available in a cartridge flange version, which is designed to be compatible with CW and CT compact planetary gearboxes. This combination provides a short final drive length for applications with space limitations.
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Input |
Valve plate |
Cylinder |
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Trunnion |
shaft |
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block |
Ball bearing
Auxiliary pad
Charge check and |
Piston |
Swashplate |
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high pressure relief |
Charge relief |
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valve with bypass |
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valve |
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P100 583E |
© Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 | 7 |
Technical Information
Series 40 Direct Displacement Pumps
General Information
Charge check and high pressure relief valve with bypass
Auxiliary
pad
Charge relief |
Charge |
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Valve plate |
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valve |
pump |
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Piston |
Ball |
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bearing |
Trunnion |
Input |
Cylinder |
Swashplate |
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shaft |
block |
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P100 584E |
A variable pump is shown in a hydraulic circuit with a fixed motor. The pump shown features manual displacement control. The circuit features suction filtration and heat exchanger.
Remote pressure filtration |
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(no charge pump) |
Remote Pressure Filtration |
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E |
D |
Suction Filtration
E M3
L2
A
M1
M2
B
No relief valve
L1 S
P100 638E
8 | © Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 |
Technical Information
Series 40 Direct Displacement Pumps
•3 sizes of variable displacement pumps
•3 sizes of tandem pumps
•3 sizes of variable displacement motors
•3 sizes of fixed displacement motors
•Efficient axial piston design
•Proven reliability and performance
•Compact, lightweight
•Worldwide sales and service
High Pressure Relief Valve (HPRV) - A high pressure relief valve limits the system pressure to protect the system from over-pressure.
Charge Relief Valve - The charge pressure relief valve regulates charge pressure.
Displacement Limiters - Optional displacement limiters allow maximum displacement adjustment to allow for fine tuning of the propel system.
Auxiliary Mounting Pads - Several auxiliary mounting pad options allow for adding a second pump. Input Shafts - Straight keyed, tapered keyed, and several splined shaft options are available.
© Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 | 9 |
Technical Information
Series 40 Direct Displacement Pumps
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: Hydraulic Fluids and Lubricants, Technical Information, 520L0463 and, Experience with Biodegradable Hydraulic Fluids, Technical Information,520L465.
Maintain fluid viscosity within the recommended range for maximum efficiency and bearing life. Minimum viscosity is acceptable only during brief occasions of maximum ambient temperature and severe duty cycle. Maximum viscosity is acceptable only at cold start: Limit speeds until the system warms up. See Danfoss publications: Hydraulic Fluids and Lubricants, Technical Information, 520L0463, and Experience with Biodegradable Hydraulic Fluids, Technical Information, 520L465.
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 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
Minimum (intermittent, cold start) |
- 40° C [- 40° F] |
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Continuous |
82.2° C [180° F] |
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Maximum |
104.4° C [220° F] |
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All systems require a charge (positive pressure) in the low side of the system loop for proper lubrication and rotating group operation. Maintain low loop (charge) pressure at a minimum of 6 bar [87 psi] above case pressure.
Maintain case pressure within the limits shown in the table. Ensure housing is 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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10 | © Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 |
Technical Information
Series 40 Direct Displacement Pumps
Operating Parameters
C Caution
Operating outside of charge and case pressure limits will damage the pump. To minimize this risk, use full size inlet and case drain plumbing, and limit line lengths.
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.
The table, Operating Parameters in the Specifications section, gives rated and maximum speeds for each displacement. Not all displacements operate under the same speed limits. Definitions of these speed limits appear below.
Continuous speed is the maximum recommended operating speed at full power condition. Operating at or below this speed should yield satisfactory product life. Do not exceed maximum motor speed during unloaded, on-road travel over level ground.
Maximum speed is the highest operating speed permitted. Exceeding maximum speed reduces pump 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.
Achieving acceptable pump life and performance requires proper charge pump inlet design. A continuous inlet pressure of not less than 0.8 bar abs. (not more than 6.3 in. Hg vac.) is recommended. Normal pressure less than the minimum inlet pressure of 0.7 bar abs. (greater than 9.2 in. Hg vac.) indicates inadequate inlet design or a restricted filter. Pressures less than 0.7 bar abs. (greater than 9.2 in. Hg vac.) during cold start are possible, but should improve quickly as the fluid warms.
© Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 | 11 |
Technical Information
Series 40 Direct Displacement Pumps
Operating Parameters
Inlet pressure
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bar absolute |
in. Hg vacuum |
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Continuous |
0.8 |
6 |
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Minimum |
0.7 |
9.2 (max) |
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The theoretical maximum flow at rated speed is a simple function of pump displacement and speed. This is a good gauge for sizing a companion motor. This does not take into account losses due to leakage or variations in displacement.
12 | © Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 |
Technical Information
Series 40 Direct Displacement Pumps
Use these equations to help choose the right pump size and displacement for your application.
Based on SI units
Flow |
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Vg • n • ηv |
(l/min) |
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1000 |
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Torque |
Input torque M= |
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Vg • |
p |
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(N•m) |
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20 • π • ηm |
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Power |
Input power P = |
M • n • π |
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Q • p |
(kW) |
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30 000 |
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600 • ηt |
Variables
SI units [US units]
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 efficiency ηm = Mechanical efficiency
ηt = Overall efficiency (ηv • ηm)
Based on US units
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Vg • n • η |
v (US gal/min) |
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231 |
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Input torque M= |
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Vg • |
p |
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(lbf•in) |
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2 • π • ηm |
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Input power P = |
M • n • π |
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Q • p |
(hp) |
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198 000 |
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1714 • ηt |
Ensure fluid entering pump is free of contaminants to prevent damage (including premature wear) to the system. Series 40 pumps 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
Locate filter 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 strategy.
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 Design Guidelines for Hydraulic Fluid Cleanliness, 520L0467.
The suction filter is placed in the circuit between the reservoir and the inlet to the charge pump as shown in the accompanying illustration.
© Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 | 13 |
Technical Information
Series 40 Direct Displacement Pumps
System Design Parameters
Suction filtration
Filter
To low pressure |
Strainer |
|
Reservoir |
||
side of loop |
||
|
||
and servo control |
|
Charge relief valve
Charge pump
To pump case
P100 588E
Provision for charge pressure filtration is available on all Series 40 pumps. The pressure filter is remotely mounted in the circuit after the charge pump, as shown in the accompanying illustration.
Filters used in charge pressure filtration circuits must be rated to at least 34.5 bar [500 psi] pressure. A 100 - 125 µm screen located in the reservoir or in the charge inlet line is recommended when using charge pressure filtration.
A filter bypass valve is necessary to prevent filter damage and to avoid contaminants from being forced through the filter media by high pressure differentials across the filter. In the event of high pressure drop associated with a blocked filter or cold start-up conditions, fluid will bypass the filter. Avoid working with an open bypass for an extended period. We recommend a visual or electrical bypass indicator. Proper filter maintenance is mandatory.
Charge filtration
Reservoir |
Strainer |
To Low Pressure |
Filter |
|
with bypass |
||
side of loop |
||
|
||
and servo control |
|
Charge relief valve
Charge pump
To pump case
P106 102E
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.
14 | © Danfoss | July 2017 |
520L0635 | BC00000106en-US0703 |