Danfoss Gear Motors User guide

Technical Information

Gear Motors

Group 1, 2, and 3

www.danfoss.com

Technical Information

Gear Motors Group 1, 2, and 3

Revision history	Table of revisions
	Date	Changed	Rev
	July 2021	Minor corrections to data made	0102
	October 2019	First edition	0101

2 | © Danfoss | July 2021

BC319483612502en-000102

Technical Information
Gear Motors Group 1, 2, and 3
Contents
General information
Overview..............................................................................................................................................................................................	5
Features and benefits.....................................................................................................................................................................	7
Motor displacements......................................................................................................................................................................	7
Determination of nominal motor size.......................................................................................................................................	8
System Requirements
Pressure................................................................................................................................................................................................	9
Speed....................................................................................................................................................................................................	9
Hydraulic Fluids..............................................................................................................................................................................	10
Temperature and Viscosity.........................................................................................................................................................	10
Filtration............................................................................................................................................................................................	11
Filters.............................................................................................................................................................................................	11
Selecting a filter.........................................................................................................................................................................	11
Reservoir......................................................................................................................................................................................	11
Line sizing-x.....................................................................................................................................................................................	12
Motor shaft connection...............................................................................................................................................................	12
Motor shaft load data form........................................................................................................................................................	13
Motor Life..........................................................................................................................................................................................	13
Group 1 Gear motors
Motor design...................................................................................................................................................................................	14
Technical data.................................................................................................................................................................................	15
Model code.......................................................................................................................................................................................	15
A Family........................................................................................................................................................................................	15
B Displacement..........................................................................................................................................................................	16
C Rotation....................................................................................................................................................................................	16
D Project version ......................................................................................................................................................................	16
E Mounting flange....................................................................................................................................................................	16
F Drive Gear................................................................................................................................................................................	16
G Rear cover................................................................................................................................................................................	17
H Inlet size; I Outlet size..........................................................................................................................................................	17
J Ports Pos & Spec Body..........................................................................................................................................................	18
K Seals...........................................................................................................................................................................................	18
L Screws........................................................................................................................................................................................	18
M Set valves................................................................................................................................................................................	18
N Type of mark...........................................................................................................................................................................	19
O Mark position.........................................................................................................................................................................	19
Motor performance graphs........................................................................................................................................................	19
Flange, shaft and port configurations....................................................................................................................................	22
Shaft options....................................................................................................................................................................................	22
Integral relief value - SKM1IN.....................................................................................................................................................	23
Variant codes for ordering intergral relief valve............................................................................................................	24
Ports dimensions............................................................................................................................................................................	26
Dimensions.......................................................................................................................................................................................	27
SKM1NN, SKU1NN, SNU1NN – 01BA..................................................................................................................................	28
SKM1NN, SKU1NN – 02BB, 02FA.........................................................................................................................................	29
SKM1NN, SKU1NN – 06GA and 06SA.................................................................................................................................	30
Group 2 Gear motors
Motor design...................................................................................................................................................................................	31
SNM2NN.......................................................................................................................................................................................	31
SNU2NN.......................................................................................................................................................................................	31
SKU2NN........................................................................................................................................................................................	32
Technical data.................................................................................................................................................................................	32
Model code.......................................................................................................................................................................................	33
A Family........................................................................................................................................................................................	33
B Displacement..........................................................................................................................................................................	34
C Rotation....................................................................................................................................................................................	34
D Project version ......................................................................................................................................................................	35
E Mounting flange....................................................................................................................................................................	35
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Technical Information
Gear Motors Group 1, 2, and 3
Contents
F Drive gear.................................................................................................................................................................................	35
G Rear cover................................................................................................................................................................................	36
H Inlet size; I Outlet size..........................................................................................................................................................	37
J Ports pos & Spec body.........................................................................................................................................................	38
K Seals...........................................................................................................................................................................................	38
L Screws........................................................................................................................................................................................	38
M Set valves................................................................................................................................................................................	38
N Type of mark...........................................................................................................................................................................	39
O Mark position.........................................................................................................................................................................	39
Motor performance graphs........................................................................................................................................................	40
Flange, shaft and port configurations....................................................................................................................................	42
Shaft options....................................................................................................................................................................................	43
Port dimensions..............................................................................................................................................................................	44
Integral relief valve - SNM2IN....................................................................................................................................................	46
Variant codes for ordering intergral relief valve............................................................................................................	47
Anti-cavitation check valve - SNM2GN...................................................................................................................................	49
Integral relief valve and anti-cavitation check valve - SNM2JN....................................................................................	49
Outrigger bearing assembly - SNM2NN................................................................................................................................	50
Allowable shaft loads..............................................................................................................................................................	51
Outrigger bearings 9A, 94, 9J, 9F, and 9H .......................................................................................................................	53
Dimensions............................................................................................................................................................................	54
Dimensions.......................................................................................................................................................................................	55
SNM2NN, SNU2NN – 01DA, 01FA and 01BA...................................................................................................................	55
SNM2NN, SNU2NN – 02DB and 02AA...............................................................................................................................	56
SNM2NN, SNU2NN – 03CA....................................................................................................................................................	57
SNM2NN, SNU2NN–04DB/05DB and 04AA/05AA........................................................................................................	58
SNM2NN, SNU2NN, SKU2NN – 06SA, 06GA....................................................................................................................	59
Group 3 Gear motors
Motor design...................................................................................................................................................................................	60
SNM3NN.......................................................................................................................................................................................	60
SNU3NN.......................................................................................................................................................................................	61
Technical data.................................................................................................................................................................................	61
Model code.......................................................................................................................................................................................	62
A Family........................................................................................................................................................................................	62
B Displacement..........................................................................................................................................................................	63
C Rotation....................................................................................................................................................................................	63
D Project version (value representing a change to the initial project).................................................................	63
E Mounting flange....................................................................................................................................................................	63
F Drive Gear................................................................................................................................................................................	64
G Rear Cover...............................................................................................................................................................................	64
H Inlet size; I Outlet size..........................................................................................................................................................	64
J Ports pos & Spec body.........................................................................................................................................................	65
K Seals...........................................................................................................................................................................................	66
L Screws........................................................................................................................................................................................	66
M Set valves................................................................................................................................................................................	66
N Type of mark...........................................................................................................................................................................	66
O Mark position.........................................................................................................................................................................	66
Motor performance graphs........................................................................................................................................................	67
Flange, shaft, and port configurations...................................................................................................................................	70
Shaft and flange availability.......................................................................................................................................................	71
Ports dimensions............................................................................................................................................................................	72
Anti-cavitation check valve - SNM3GN...................................................................................................................................	75
Dimensions.......................................................................................................................................................................................	76
SNM3NN, SNU3NN – 01FA, 01DA and 01BA...................................................................................................................	76
SNM3NN, SNU3NN – 02FA, 02DB and 02AA...................................................................................................................	77
SNM3NN, SNU3NN – 03FB and 03BB.................................................................................................................................	78
SNM3NN, SNU3NN – 06AA....................................................................................................................................................	79
SNM3NN, SNU3NN – 07BC, 07SA and 07GA...................................................................................................................	80

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Technical Information

Gear Motors Group 1, 2, and 3

General information

Overview

The DanfossGear Motors is a range of peak performance fixed displacement hydraulic motors available in three different frame sizes: Group 1, Group 2, and Group 3, all as uniand bidirectional version.

Constructed of a high strength extruded aluminum body with aluminum rear cover and aluminum front flange, all motors are balanced for exceptional efficiency and designed to ensure an excellent starting torque and, in the bidirectional version, to guarantee the ability to work with high back pressure and extremely low system pressure.

The flexibility of the range in each frame size combined with the high efficiency and low starting torque makes the Danfoss Gear Motors ideal for a wide range of applications sectors including onand offhighway hydraulic fan drive systems, turf care, road bildge, fork lifts and municipal.

All the unidirectional motors have the same construction of the correspondent pump as well but, with inlet and outlet positioned at the opposite side for the same rotation.

Some representatives of gear motors

SKM1NN 06SA

SNM2NN9JDB

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Technical Information

Gear Motors Group 1, 2, and 3

General information

SNM3NN01BA

SNU2NN 06SA

SNM3NL 07SA

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Technical Information

Gear Motors Group 1, 2, and 3

General information

SNU2NN 06GB

Features and benefits

•Three groups of frame sizes (Group 1, 2 and 3)

•Displacements from 2.6 to 90 cm3/rev [from 0.158 to 5.49 in3/rev]

•Available in uniand bidirectional version for all the frame sizes, displacements and configurations

•Rated pressure up to 250 bar [3625 psi]

•Back pressure capability up to 250 bar [3625 psi]

•Speeds up to 4000 min-1 (rpm) for Group 1 and 2, and up to 2500 min-1 (rpm) for Group 3

•SAE, ISO and DIN mounting flanges and shafts

•Available with integrated relief valve in the Group 2 frame size and integrated anti-cavitation valve in Group 2 and Group 3 frame sizes

Motor displacements

Quick reference chart for unidirectional motor models (Group 1, 2 and 3)

	300
<![if ! IE]> <![endif]>bar																			SKU1NN
	250																		SNU1NN
																			SKU2NN
<![if ! IE]> <![endif]>pressure	200																		SNU2NN
																			SNU3NN
	150
	100
<![if ! IE]> <![endif]>Rated
	50
	0
	0	5	10	15	20	25	30	35	40	45	50	55	60	65	70	75	80	85	90	95

Displacement cm3/rev

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Technical Information

Gear Motors Group 1, 2, and 3

General information

Quick reference chart for bidirectional motor models (Group 1, 2 and 3)

	300
<![if ! IE]> <![endif]>bar	250																		SKM1NN
																			SNM2NN
																			SNM3NN
<![if ! IE]> <![endif]>pressure	200
	150
	100
<![if ! IE]> <![endif]>Rated
	50
	0
	0	5	10	15	20	25	30	35	40	45	50	55	60	65	70	75	80	85	90	95

Displacement cm3/rev

Determination of nominal motor size

Based on SI units

Qe

=

Vg • n

1000 •

v

Me

=

Vg • p •

mh

20 •

Pe =

Me • n

=

Qe • p • t

9550

600

n =

Qe • 1000 • v

Vg

Where:

Qe

Input flow (l/min)

Me

Output torque (N•m)

Pe

Output power (kW)

n

Speed (min-1)

Vg

Motor displacement per rev. (cm3/rev)

phigh

High pressure (bar)

plow

Low pressure (bar)

∆p

High pressure minus Low pressure (bar)

ηv

Motor volumetric efficiency

ηmh

Mechanical-hydraulic efficiency

ηt

Motor total efficiency (ηv • ηmh)

Based on US units
Qe	=			Vg • n
				231 •	v
Me	=			Vg •	p •		mh
				2 •
Pe =				Vg • n • p • t
				396 000
n =				Qe • 231 •			v
					Vg
Where:
Qe				Input flow [US gal/min]
Me				Output torque [lb•in]
Pe				Output power [hp]
n				Speed [rpm]
Vg				Motor displacement per rev. [in3/rev]
phigh				High pressure [psi]
plow				Low pressure [psi]
∆p				High pressure minus Low pressure [psi]
ηv				Motor volumetric efficiency
ηmh				Mechanical-hydraulic efficiency
ηt				Motor total efficiency (ηv • ηmh)

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Technical Information

Gear Motors Group 1, 2, and 3

System Requirements

Pressure

Peak pressure is the highest intermittent pressure allowed.

The relief valve overshoot (reaction time) determines peak pressure. It is assumed to occur for less than 100 ms.

The illustration to the right shows peak pressure in relation to rated pressure and reaction time (100 ms maximum).

Rated pressure is the average, regularly occurring operating inlet pressure that should yield satisfactory product life. The maximum machine load at the motor shaft determines rated pressure

<![if ! IE]> <![endif]>Pressure	Peak pressure
	Rated pressure
	Reaction time (100 ms max)
	Time

System pressure is the differential between the inlet and outlet ports. It is a dominant operating variable affecting hydraulic unit life. High system pressure, resulting from high load at the motor shaft, reduces expected life. System pressure must remain at, or below, rated pressure during normal operation to achieve expected life.

Back pressure is the average, regularly occurring operating outlet pressure that should yield satisfactory bidirectional motor life. The hydraulic load demand downstream of the motor determines the back pressure. Unidirectional motors cannot work with back pressure and the maximum back pressure allowed is 5 bar [72 psi] rated and 7 bar [101 psi ] as peak.

Case Drain Pressure is the regularly occurring case drain line pressure that should yield satisfactory bidirectional motor life. It is recommended to design the case drain piping connecting the case drain direct to the tank in order to keep the case drain pressure as low as possible. The max. continuous case drain pressure allowed is 5 bar [72 psi] rated and 7 bar [101 psi] as peak.

Speed

Maximum speed is the limit recommended by Danfoss for a particular gear motor when operating at rated pressure. It is the highest speed at which normal life can be expected.

The lower limit of operating speed is the minimum speed. It is the lowest speed at which normal life can be expected.

The minimum speed increases as operating system pressure increases. When operating under higher pressures, a higher minimum speed must be maintained, as illustrated below.

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Technical Information

Gear Motors Group 1, 2, and 3

System Requirements

Speed versus pressure

Rated

<![if ! IE]>

<![endif]>Pressure

P1

Operating envelope

0

N1	N2	Max
	Speed

Where:

N1 = Minimum speed at 100 bar

N2 = Minimum speed at rated pressure

Hydraulic Fluids

Ratings and data for gear motors are guaranteed when the hydraulic system operates with premium hydraulic fluids without containing oxidation, rust, or foam inhibitors.

These fluids have to work with good thermal and hydrolytic stability to prevent wear, erosion, or corrosion of internal components. They include:

•Hydraulic fluids following DIN 51524, part 2 (HLP) and part 3 (HVLP) specifications

•API CD engine oils conforming to SAE J183

•M2C33F or G automatic transmission fluids

•Certain agricultural tractor fluids

C Caution

Use only clean fluid in the gear motors and hydraulic circuit. Never mix hydraulic fluids.

Temperature and Viscosity

Temperature and viscosity requirements must be concurrently met. Use of petroleum/mineral-based fluids is highly recommended.

High temperature limits apply at the inlet port of the motors. The motors should operate at or below the maximum continuous temperature. The peak temperature is based on material properties.

Don’t exceed it.

Minimum (cold start) temperature relates to the physical properties of component materials.

Cold oil, generally, doesn’t affect the durability of motors components. It may affect the ability of oil to flow and transmit power. For this reason, keep the temperature at 16°C [60 °F] above the pour point of the hydraulic fluid.

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Technical Information

Gear Motors Group 1, 2, and 3

System Requirements

Temperature limits (with standard NBR seals)

Minimum (cold start)	Maximum continuous	Peak (intermittent)
-20°C [-4°F]	80°C [176°F]	90°C [194°F]

Minimum viscosity occurs only during brief occasions of maximum ambient temperature and severe duty cycle operation.

Maximum viscosity occurs at cold start only. During this condition, limit speeds until the system warms up.

•Size heat exchangers to keep the fluid within these limits

•Test regularly to verify that these temperatures and viscosity limits aren’t exceeded

•Keep the fluid viscosity in the recommended viscosity range for maximum unit efficiency and bearing life

Fluid viscosity limits, in mm2/s [SUS]

Maximum (cold start)	Recommended range	Range for high efficiency	Minimum
1600 [7273]	12-100 [66-456]	20-50 [97-231]	10 [60]

Filtration

Filters

Use a filter that conforms to Class 22/18/13 of ISO 4406 (or better). It may be on the motor outlet (discharge filtration) or inlet (pressure filtration).

Selecting a filter

When selecting a filter, please consider:

•Contaminant ingression rate (determined by factors such as the number of actuators used in the system)

•Generation of contaminants in the system

•Required fluid cleanliness

•Desired maintenance interval

•Filtration requirements of other system components

Measure filter efficiency with a Beta ratio (βX). βx ratio is a measure of filter efficiency defined by ISO 4572. It is the ratio of the number of particles greater than a given diameter (in microns) upstream of the filter to the number of these particles downstream of the filter.

•For discharge filtration with controlled reservoir ingression, use a β35-45 = 75 filter

•For pressure filtration, use a filtration with an efficiency of β10 = 75

The filtration requirements for each system are unique. Evaluate filtration system capacity by monitoring and testing prototypes.

Fluid cleanliness level and βX ratio

Fluid cleanliness level (per ISO 4406)	Class 22/18/13 or better
βX ratio (discharge filtration)	β35-45 = 75 and β10 = 2
βX ratio (pressure or return filtration)	β10 = 75
Recommended inlet screen size	100 – 125 μm [0.004 – 0.005 in]

Reservoir

The reservoir provides clean fluid, dissipates heat, removes entrained air, and allows fluid volume changes associated with fluid expansion and cylinder differential volumes. A correctly sized reservoir

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Technical Information

Gear Motors Group 1, 2, and 3

System Requirements

accommodates maximum volume changes during all system operating modes. It promotes de-aeration of the fluid as it passes through, and accommodates a fluid dwell-time between 60 and 180 seconds, allowing entrained air to escape.

Minimum reservoir capacity depends on the volume required to cool and hold the oil from all retracted cylinders, allowing for expansion due to temperature changes. A fluid volume of 1 to 3 times the pump output flow (per minute) is satisfactory. The minimum reservoir capacity is 125% of the fluid volume.

Install the suction line above the bottom of the reservoir to take advantage of gravity separation and prevent large foreign particles from entering the line. Cover the line with a 100-125 micron screen. The pump should be below the lowest expected fluid level.

Put the return-line below the lowest expected fluid level to allow discharge into the reservoir for maximum dwell and efficient deaeration. A baffle (or baffles) between the return and suction lines promotes deaeration and reduces fluid surges.

Line sizing-x

Choose pipe sizes that accommodate minimum fluid velocity to reduce system noise, pressure drops, and overheating. This maximizes system life and performance.

Design inlet piping that maintains continuous pump inlet pressure above 0.8 bar absolute during normal operation. The line velocity should not exceed the values in the table below:

Maximum line speed

Inlet	Outlet	Return
5 m/s [16.4 ft/sec]	2.5 m/s [8.2 ft/sec]	3 m/s [9.8 ft/sec]

Most systems use hydraulic oil containing 10% dissolved air by volume.

Over-aeration, or entrained air is the result of flow line restrictions, where the dissolved air comes out of solutions, or when air is allowed to leak into the hydraulic circuit. These include inadequate pipes size, sharp bends, or elbow fittings causing a reduction of flow-line cross-sectional area. This problem will not occur if these circuit recommendations are followed, rated speed requirements are maintained, and reservoir size and location are adequate.

Motor shaft connection

Shaft options for gear motors include tapered, splined, and parallel shafts.

Plug-in drives, with a splined shaft, can impose severe radial loads when the mating spline is rigidly supported. Increasing spline clearance does not alleviate this condition.

Use plug-in drives only if the concentricity between the mating spline and pilot diameter is within 0.1 mm [0.004 in]. Lubricate the drive by flooding with oil. A three-piece coupling minimizes radial or thrust shaft loads.

Motor shaft connection

Pilot cavity

Mating spline

Ø 0.1 [0.004]

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Technical Information

Gear Motors Group 1, 2, and 3

System Requirements

To avoid spline shaft damage, use carburized and hardened steel couplings with 80-82 HRA surface hardness.

Motor shaft load data form

Photocopy this page and fax the complete form to your Danfoss representative for an assistance. This illustration shows a motor with counterclockwise orientation:

Radial load (R L)

Axial load (AL)

	a	90o
		α
		Inlet port
	180o	0o

	270o
	RL
Application data
Item	Value	Based on SI or US units
Motor displacement		□ cm3/rev	□ in3/rev
Rated system pressure		□ bar	□ psi
Peak pressure
Motor shaft rotation		□ left	□ right
Motor minimum speed		min-1 (rpm)
Motor maximum speed
Radial load	R1	□ N	□ lbf
Angular orientation of radial load to inlet port	α	degree
Axial load	A1	□ N	□ lbf
Distance from flange to radial load	a	□ mm	□ in

Motor Life

Motor life is a function of speed, system pressure, and other system parameters (such as fluid quality and cleanliness).

All Danfoss gear motors use hydrodynamic journal bearings that have an oil film maintained between the gear/shaft and bearing surfaces at all times. If the oil film is sufficiently sustained through proper system maintenance and operating within recommended limits, long life can be expected.

High pressure impacts motor life. When submitting an application for review, provide machine duty cycle data that includes percentages of time at various loads and speeds.

B10 life expectancy number is generally associated with rolling element bearings. It does not exist for hydrodynamic bearings.

Danfoss strongly recommends a prototype testing program to verify operating parameters and their impact on life expectancy before finalizing any system design.

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Technical Information

Gear Motors Group 1, 2, and 3

Group 1 Gear motors

Motor design

SKM1NN

SKM1NN is the Group 1 bidirectional motor available in the whole displacements range from 2.6 up to 12 cm3/rev [from 0.158 up to 0.732 in3/ rev].

Configurations include European and SAE flanges and shafts (Code 01BA, 02BB, 02FA, 06GA, 06SA).

SKM1NN 06SA

SKU1NN

SKU1NN is a Group 1 unidirectional motor available in the whole displacements range from 2.6 up to 12 cm3/rev [from 0.158 up to 0.732 in3/rev]. The SKU1NN motor construction is derived from the correspondent pump SKP1NN.

Configurations include European and SAE flanges and shafts (Code 01BA, 02BB, 02FA, 06GA, 06SA).

SNU1NN

SNU1NN is a Group 1 unidirectional motor available in a limited displacements range from 2.6 up to 7.8 cm3/rev [from 0.158 up to 0.464 in3/rev]. The SNU1NN motor construction is derived from the correspondent pump SNP1NN. Configurations include European flange and shaft (Code 01BA).

SNU1NN 01BA (cut-away)

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Technical Information

Gear Motors Group 1, 2, and 3

Group 1 Gear motors

Technical data

		Frame size
		2,6	3,2	3,8	4,3	6,0	7,8	010	012
Displacement	cm3/rev [in3/rev]	2.62	3.14	3.66	4.19	5.89	7.59	9.94	12
		[0.158]	[0.195]	[0.231]	[0.262]	[0.366]	[0.463]	[0.607]	[0.732]
SKM1NN (a standard, bidirectional motor)
Peak pressure	bar [psi]	270	270	270	270	250	220	180	150
		[3915]	[3915]	[3915]	[3915]	[3625]	[3190]	[2610]	[2175]
Rated pressure		250	250	250	250	230	200	160	130
		[3625]	[3625]	[3625]	[3625]	[3335]	[2900]	[2320]	[1895]
Back pressure		250	250	250	250	230	200	160	130
		[3625]	[3625]	[3625]	[3625]	[3335]	[2900]	[2320]	[1895]
Minimum speed	min-1 (rpm)	1000	1000	1000	800	800	800	800	800
Maximum speed		4000	4000	3000	3000	2000	2000	2000	2000
SKU1NN (a standard, unidirectional motor)
Peak pressure	bar [psi]	270	270	270	270	250	220	170	140
		[3915]	[3915]	[3915]	[3915]	[3625]	[3190]	[2465]	[2030]
Rated pressure		250	250	250	250	230	200	150	120
		[3625]	[3625]	[3625]	[3625]	[3335]	[2900]	[2175]	[1740]
Minimum speed	min-1 (rpm)	1000	1000	1000	800	800	800	800	800
Maximum speed		4000	4000	3000	3000	2000	2000	2000	2000
SNU1NN (a standard, unidirectional motor)
Peak pressure	bar [psi]	270	270	270	270	190	180	–
		[3915]	[3915]	[3915]	[3915]	[2755]	[2610]
Rated pressure		250	250	250	250	170	160
		[3625]	[3625]	[3625]	[3625]	[2465]	[2320]
Minimum speed	min-1 (rpm)	1000	1000	1000	800	800	800
Maximum speed		4000	4000	3000	3000	2000	2000
All
Weight	kg [lb]	1.02	1.14	1.18	1.20	1.30	1.39	1.55	1.65
		[2.26]	[2.51]	[2.60]	[2.65]	[2.87]	[3.06]	[3.42]	[3.64]
Moment of inertia of rotating	x 10-6 kg•m2	5.1	5.7	6.4	7.1	9.3	11.4	14.6	17.1
components	[x 10-6 lbf•ft2]	[121.0]	[135.2]	[151.9]	[168.5]	[220.7]	[270.5]	[339.4]	[405.8]

1 kg•m2 = 23.68 lb•ft2

C Caution

The rated and peak pressure mentioned are for motors with flanged ports only. When threaded ports are required a derated performance has to be considered. To verify the compliance of an high pressure application with a threaded ports pump apply to a Danfoss representative.

Model code

A Family

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

●

●

●

●

●

●

/

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Technical Information

Gear Motors Group 1, 2, and 3

Group 1 Gear motors

SNU1NN	Unidirectional gear motor
SKU1NN	High torque unidirectional gear motor
SKM1NN	Bidirectional gear motor
SKM1IN	Bidirectional gear motor with relief valve

B Displacement

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

●

●

●

/

2,6

2.62 cc

3,2

3.14 cc

3,8

3.66 cc

4,3

4.19 cc

6,0

5.89 cc

7,8

7.59 cc

010

9.94 cc

012

12.0 cc

C Rotation

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

●

/

L

Left (Counterclockwise)

R

Right (Clockwise)

B

Bidirectional

D Project version

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

●

/

N

Std Version of Project

E Mounting flange

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

●

●

/

01

European

4 bolt flange with pilot Ø25,4 mm

02

European

4 bolt flange with pilot Ø30 mm

06

SAE A-A 2 bolt flange with pilot Ø50,8 mm

F Drive Gear

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

●

●

/

16 | © Danfoss | July 2021

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Technical Information

Gear Motors Group 1, 2, and 3

Group 1 Gear motors

BA	Taper 1:8-M7-Key2,41 SKP1
BB	Taper 1:8-M10x1-Key 3
FA	Parallel Ø12-Thread M10x1-Key 3
GA	Parallel Ø12,7-Key 3,2
SA	SAE spline J498-9T-20/40 Flat Root Side FIT-L15

G Rear cover

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

●

●

/

P1

Standard cover for unidirectional motors

M1

Standard cover for motors drain M12x1,5

M2

Cover with drain 1/8" Gas

M3

Cover with drain 1/4" Gas

M6

Cover with drain 7/16-20UNF-2B

MH

Cover with drain M12x1,5 ISO6149

I1

Cover for unidirectional motors with relief valve

L6

Cover motor with side drain in vertical axis 7/16-20UNF-2B

V1

Cover for bidirectional motors with relief valve with drain 1/4 Gas

H Inlet size; I Outlet size

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

●

●

●

●

/

B2

13x30xM6

C1 8x26xM5

C2 12x26xM5

C3 13,5x30xM6

D3 M14x1,5

D5 M18x1,5

D7 M22x1,5

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Technical Information

Gear Motors Group 1, 2, and 3

Group 1 Gear motors

E3

9/16-18UNF

E4

3/4-16UNF

E5

7/8-14UNF

F2

1/4 GAS

F3

3/8 GAS

F4

1/2 GAS

H2

10xM12x1,5-ISO6149

H4

12xM16x1,5-ISO6149

H5

12xM18x1,5-ISO6149

H7

13,5xM22x1, 5-ISO6149

J Ports Pos & Spec Body

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

●

●

/

N

Std from catalog

K Seals

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

●

/

N

Standard NBR seal

H

VITONseals + special backing ring - special for SKU1NN

L Screws

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

●

/

N

Std screws

B

GEOMET screws - Anticorrosion screws

M Set valves

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

/

●

●

●

NNN

No valve

V*

Integralrelief valve pressure setting

* For details, see Variant codes for ordering intergral relief valve on page 24.

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Technical Information

Gear Motors Group 1, 2, and 3

Group 1 Gear motors

N Type of mark

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

/

●

N

Standard Danfoss Marking

A

Standard Danfoss Marking+Customer Code-Special

Z

Without Marking

O Mark position

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

/

●

N

Std Marking position (on top)

A

Special Marking position on the bottom

Motor performance graphs

The following graphs provide typical inlet flow and output torque for Group 1 motors at various working pressures. Data were taken using ISO VG46 petroleum /mineral based fluid at 50 °C [122 °F] (viscosity = 28 mm2/s [132 SUS]).

© Danfoss | July 2021

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Technical Information

Gear Motors Group 1, 2, and 3

Group 1 Gear motors

20 | © Danfoss | July 2021

BC319483612502en-000102

Technical Information

Gear Motors Group 1, 2, and 3

Group 1 Gear motors

© Danfoss | July 2021

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Technical Information

Gear Motors Group 1, 2, and 3

Group 1 Gear motors

Flange, shaft and port configurations

...For SKM1NN and SKU1NN

Code	Flange	Shaft				Port
01BA	European 01, 4-	Taper 1:8				European in
	bolts pilot Ø					+ pattern
	25.4 mm [1.0 in]
02BB European 02, 4-		Taper 1:8				German
	bolts pilot Ø 30					standard in X
	mm [1.181]					pattern

02FA	European 02, 4-	Parallel									European in
	bolts pilot Ø 30	12 mm [0.472 in]									+ pattern
	mm [1.181]
06GA	SAE A-A 2-bolts	Parallel									Threaded
		12.7 mm [0.5 in]									SAE O-ring
											boss

06SA SAE A-A 2-bolts	SAE A-A	Threaded
	9-teeth splined	SAE O-ring
		boss

...For SNU1NN

Code	Flange	Shaft	Port
01BA	European 01, 4-	Taper 1:8	European in
	bolts pilot Ø		+ pattern
	25.4 mm [1.0 in]

Shaft options

Group 1 motors are available with a variety of splined, parallel, and tapered shaft ends. Not all shaft styles are available with all flange styles.

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

●

●

/

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Technical Information

Gear Motors Group 1, 2, and 3

Group 1 Gear motors

Shaft		Mounting flange code with maximum torque
Code	Description	01	02	06
BA	Taper 1:8	25 [221]	-	-
BB	Taper 1:8	-	50 [442]	-
DB	Splined Z15-m0,75-alfa 30°-L14	-	35 [309]	-
FA	Parallel 12 mm [0.47 in]	-	24 [212]	-
GA	Parallel 12.7 mm [0.50 in]	-	-	32 [283]
SA	SAE spline J 498-9T-20/40DP	-	-	34 [301]

Recommended mating splines for Group 1 splined output shafts should be in accordance with SAE J498 or DIN 5482. Danfoss external SAE splines are flat root side fit with circular tooth thickness reduced by 0.127 mm [0.005 in] in respect to class 1 fit. The external DIN splines have an offset increased by 0.1 mm [0.004 in]. These dimensions are modified in order to assure a clearance fit with the mating spline.

Other shaft options may exist. Contact your Danfoss representative for availability.

C Caution

Shaft torque capability may limit allowable pressure. Torque ratings assume no external radial loading. Applied torque must not exceed these limits, regardless of stated pressure parameters. Maximum torque ratings are based on shaft torsional fatigue strength.

Integral relief value - SKM1IN

Danfoss offers an optional integral relief valve integrated in the Group 1 motors rear cover. It is drained internally and directs all the flow from the motor inlet to the outlet when the inlet pressure reaches the valve setting.

The tables below show applicable variant codes for ordering motors with integral relief valve. Refer to Model code on page 15 for more information.

Valve schematic diagram

© Danfoss | July 2021

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Technical Information

Gear Motors Group 1, 2, and 3

Group 1 Gear motors

Integral relief valve rear cover cross section

Inlet

Drain

P101 016

Pressure vs flow

[psi] bar 400

[5000]

[4000] 300

[3000] 200

[2000]

100

[1000]

00

0

With mineral oil at 26 mm2/s

					MINIMUM		VALVE SETTIN
10					20		30		40
									l/min
[2]			[4]		[6]		[8]		[10]
							[US gal/min]

Variant codes for ordering intergral relief valve

Variant codes for ordering integral relief valve

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

/

V

●

●

M Variant code (left part)

Code	Motor speed for RV setting
	min-1 (rpm)
A	not defined
C	500
E	1000
F	1250
G	1500
K	2000
I	2250
L	2500
M	2800

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Technical Information

Gear Motors Group 1, 2, and 3

Group 1 Gear motors

M Variant code (left part) (continued)

Code	Motor speed for RV setting
	min-1 (rpm)

N3000

O3250

M Variant code (right part)

Code	Pressure setting bar
	[psi]
A	no setting
B	no valve
C	18 [261]

D25 [363]

E30 [435]

F35 [508]

G40 [580]

J	150 [2175]
K	50 [725]
L	60 [870]

M70 [1015]

N80 [1160]

O90 [1305]

P100 [1450]

Q110 [1595]

R120 [1740]

S130 [1885]

T140 [2030]

U160 [2321]

V170 [2466]

W180 [2611]

X210 [3046]

Z	250 [3626]

© Danfoss | July 2021

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