Danfoss Series 40 Direct Displacement Pumps User guide

Technical Information

Series 40 Direct Displacement Pumps

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Technical Information

Series 40 Direct Displacement Pumps

Revision history	Table of revisions
	Date	Changed	Rev
	July 2017	Removed outdated images	0703
	January 2017	Minor updates	0702
	July 2015	Minor edits	0701
	February 2015	Danfoss layout	GA
	Sep 2013	Change system pressure specs	FB
	Aug 2013	Remove M46 from manual	FA
	Feb 2010	Fix Osaka address	EI
	Jun 2009	Remove M25U outline drawing	EH
	Jul 2008	Add plug for Charge pressure construction port	EG
	Oct 2007	Identified A Pad and B Pad as M35 and M44	EF
	Jul 2007	orrections to table - G factors for sample applications	ED
	Jun 2006	Corrections to maximum flow	EC
	May 2006	Added an illustration to page 21	EB

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Technical Information
Series 40 Direct Displacement Pumps
Contents
Specifications
Design Specifications......................................................................................................................................................................	5
Technical Specifications.................................................................................................................................................................	5
Operating Parameters.....................................................................................................................................................................	5
Options.................................................................................................................................................................................................	5
Fluid Specifications..........................................................................................................................................................................	6
General Information
Series 40 Family of Pumps and Motors.....................................................................................................................................	7
M25 Variable Pump..........................................................................................................................................................................	7
M35 Variable Pump (M44 is similar)...........................................................................................................................................	8
M35/44 Pump Schematic..............................................................................................................................................................	8
Features and Options
Key Features.......................................................................................................................................................................................	9
Options.................................................................................................................................................................................................	9
Operating Parameters
Fluids..................................................................................................................................................................................................	10
Viscosity.............................................................................................................................................................................................	10
Temperature....................................................................................................................................................................................	10
Charge Pressure..............................................................................................................................................................................	10
Case Pressure...................................................................................................................................................................................	10
Pressure Ratings.............................................................................................................................................................................	11
Speed Ratings..................................................................................................................................................................................	11
Inlet Pressure...................................................................................................................................................................................	11
Theoretical Output........................................................................................................................................................................	12
System Design Parameters
Sizing Equations.............................................................................................................................................................................	13
Filtration............................................................................................................................................................................................	13
Suction filtration.......................................................................................................................................................................	13
Charge filtration........................................................................................................................................................................	14
Redundant Braking System Requirement.............................................................................................................................	14
Loop Flushing..................................................................................................................................................................................	15
Reservoir............................................................................................................................................................................................	15
Case Drain usage for Tandem Pumps.....................................................................................................................................	15
Bearing Life and External Shaft Loading ...............................................................................................................................	15
Hydraulic Unit Life.........................................................................................................................................................................	16
Mounting Flange Loads...............................................................................................................................................................	17
Model Code
Model Code......................................................................................................................................................................................	19
Options
Charge Pump...................................................................................................................................................................................	21
Charge Pump Output Flow........................................................................................................................................................	22
Charge Pump Power Requirements........................................................................................................................................	22
Charge Relief Valve........................................................................................................................................................................	22
Charge Check/High Pressure Relief Valve (HPRV)..............................................................................................................	23
Auxiliary Mounting Pads and Auxiliary Pumps...................................................................................................................	24
Shaft Options...................................................................................................................................................................................	26
M25 Variable Pump.......................................................................................................................................................................	27
M25 Tandem Pump.......................................................................................................................................................................	28
M35/44 Variable Pump................................................................................................................................................................	29
M35/44 Tandem Pump................................................................................................................................................................	30
Direct Displacement Control (DDC)........................................................................................................................................	31
External control handle requirements..............................................................................................................................	31
Installation Drawings
M25 Variable Pump.......................................................................................................................................................................	33
M25 Tandem Pump.......................................................................................................................................................................	35
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Technical Information
Series 40 Direct Displacement Pumps
Contents
M35/44 Variable Pump................................................................................................................................................................	37
M35/44 Tandem Pump................................................................................................................................................................	39
Performance Data
Performance.....................................................................................................................................................................................	41
Schematics
Single Pump Schematics.............................................................................................................................................................	42
Tandem Pump Schematics.........................................................................................................................................................	43

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Technical Information

Series 40 Direct Displacement Pumps

Specifications

Design Specifications

Product line	Series 40 Pumps
Pump type	In-line, axial piston, variable, positive displacement pumps
Direction rotation	Clockwise (CW) or counterclockwise (CCW) available
Installation position	Discretionary, the housing must be filled with hydraulic fluid
Filtration configuration	Suction or charge pressure filtration
Other system requirements	Independent braking system, suitable reservoir and heat exchanger

Technical Specifications

Model	Unit	M25 PV	M35 PV	M44 PV	M25 PT	M35 PT	M44 PT
Pump		Single variable pump			Tandem variable pump
configuration
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
	[in3/rev]				[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]
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]

Operating Parameters

Model	Unit	M25 PV	M35 PV	M44 PV	M25 PT	M35 PT	M44 PT
Case pressure
Continuous	bar [psi]	1.7 [25]
Maximum	bar [psi]	5.2 [75]
Speed limits
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
Maximum Working	bar [psi]	345	380 [5511]	345	345	380	345
		[5000]		[5000]	[5000]	[5511]	[5000]
Maximum	bar [psi]	385	415 [6019]	415	385	415	415
		[5584]		[6019]	[5584]	[6019]	[6019]
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]
Inlet pressure
Continuous	bar absolute	0.8 [6.3]
	[in Hg vacuum]
Maximum	bar absolute	0.7 [9.2]
	[in Hg vacuum]

Options

Model	Unit	M25 PV	M35 PV	M44 PV	M25 PT	M35 PT	M44 PT
Type of mounting		SAE B	SAE B	SAE B	SAE B	SAE B	SAE B
Port connections		Twin	Twin	Twin	Twin	Twin	Twin

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Technical Information

Series 40 Direct Displacement Pumps

Specifications

Model	Unit	M25 PV	M35 PV	M44 PV	M25 PT	M35 PT	M44 PT
Integral charge pump	cm3/rev	-	11.8	11.8	-	16.4	16.4
(std)	[in3/rev]		[0.72]	[0.72]		[1.00]	[1.00]
Charge relief valve	bar [psi]	14.0	14.0	14.0	14.0	14.0	14.0
setting		[200]	[200]	[200]	[200]	[200]	[200]
System pressure	bar [psi]	140-345 [2030-5000]
regulation
Displacement limiters		-	-	-	-	-	-
Input shaft option		Splined, Tapered, or Straight Key
Auxiliary mounting		SAE A	SAE A	SAE A	SAE A	SAE A	SAE A
pad			SAE B	SAE B		SAE B	SAE B
Control options		DDC	DDC	DDC	DDC	DDC	DDC
Filtration		Suction Filtration or Remote Charge Pressure Filtration
configuration

Fluid Specifications

Parameter		Unit	Minimum	Continuous	Maximum
Viscosity		mm2/sec (cSt)	7	12-60	1600
		[SUS]	[47]	[70-278]	[7500]
Temperature		°C [°F]	-40 [-40]	82 [180]	104 [220]
Cleanliness			ISO 4406 Class 18/13 or better
Filtration efficiency	suction filtration		β35-44=75 (β10≥1.5)
	charge filtration		β15-20=75 (β10≥10)

Ratings and data are based on operation with premium petroleum-based hydraulic fluids containing oxidation, rust, and foam inhibitors.

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Technical Information

Series 40 Direct Displacement Pumps

General Information

Series 40 Family of Pumps and Motors

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.

M25 Variable Pump

		Input	Valve plate	Cylinder
	Trunnion	shaft
				block

Ball bearing

Auxiliary pad

	Charge check and	Piston	Swashplate
	high pressure relief	Charge relief
	valve with bypass
		valve
			P100 583E

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Technical Information

Series 40 Direct Displacement Pumps

General Information

M35 Variable Pump (M44 is similar)

Charge check and high pressure relief valve with bypass

Auxiliary

pad

Charge relief	Charge		Valve plate
valve	pump		Piston	Ball
				bearing
Trunnion	Input	Cylinder	Swashplate
	shaft	block
				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.

M35/44 Pump Schematic

Remote pressure filtration
(no charge pump)	Remote Pressure Filtration
E	E	D

Suction Filtration

E M3

L2

A

M1

M2

B

No relief valve

L1 S

P100 638E

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Technical Information

Series 40 Direct Displacement Pumps

Features and Options

Key Features

•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

Options

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.

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Technical Information

Series 40 Direct Displacement Pumps

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: Hydraulic Fluids and Lubricants, Technical Information, 520L0463 and, Experience with Biodegradable Hydraulic Fluids, Technical Information,520L465.

Viscosity

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
Continuous	12-60	70-278
Maximum	1600	7500

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

Minimum (intermittent, cold start)	- 40° C [- 40° F]
Continuous	82.2° C [180° F]
Maximum	104.4° C [220° F]

Charge Pressure

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.

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]
Intermittent (cold start)	5.2 bar [75 psi]

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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.

Pressure Ratings

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 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.

Inlet Pressure

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.

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Technical Information

Series 40 Direct Displacement Pumps

Operating Parameters

Inlet pressure

	bar absolute	in. Hg vacuum
Continuous	0.8	6
Minimum	0.7	9.2 (max)

Theoretical Output

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.

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Technical Information

Series 40 Direct Displacement Pumps

System Design Parameters

Sizing Equations

Use these equations to help choose the right pump size and displacement for your application.

Based on SI units

Flow	=			Vg • n • ηv					(l/min)
				1000
Torque	Input torque M=			Vg •	p				(N•m)
			20 • π • ηm
Power	Input power P =	M • n • π			=	Q • p			(kW)
		30 000
						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

=			Vg • n • η			v (US gal/min)
	231
Input torque M=			Vg •	p				(lbf•in)
		2 • π • ηm
Input power P =	M • n • π			=	Q • p			(hp)
	198 000
					1714 • ηt

Filtration

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.

Suction filtration

The suction filter is placed in the circuit between the reservoir and the inlet to the charge pump as shown in the accompanying illustration.

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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

Charge filtration

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

Redundant Braking System Requirement

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.

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