ZF DUOPLAN 2K121 User manual

Operating Instructions
ZF-DUOPLAN
Two-speed Gearbox
2K120 / 2K121
Industrial Drives

Copyright © ZF Friedrichshafen AG
This document is protected by copyright.
Complete or partial reproduction or dissemination of this document is
prohibited without the consent of ZF Friedrichshafen AG. Infringements lead
to civil and criminal prosecution.

Contents
EN 4161.758.101m – 2018-09 3
1Preface...................................................................................................................................5
1.1Validity and field of application.....................................................................................................5
1.2Service products ..........................................................................................................................5
2Safety.....................................................................................................................................6
2.1Signal words and symbols............................................................................................................6
2.2General safety instructions ...........................................................................................................6
2.3Product-specific safety instructions ..............................................................................................8
3Application and Design..........................................................................................................9
3.1Application...................................................................................................................................9
3.2Features .......................................................................................................................................9
3.3Design........................................................................................................................................10
3.4Technical data............................................................................................................................11
3.5Installation positions...................................................................................................................12
4Initial Installation .................................................................................................................13
4.1Axial runout, radial runout and length tolerances – drive motor..................................................13
4.2Balancing ...................................................................................................................................14
4.2.1Semi-key balancing ....................................................................................................................14
4.2.2Full-key balancing ......................................................................................................................14
4.2.3Motor shafts/hubs without keyways ...........................................................................................15
4.3Adaptation, motor/gearbox ........................................................................................................16
4.3.1Open design...............................................................................................................................16
4.3.2Closed design with hub bearing and shaft sealing ring...............................................................17
4.3.3Closed version (with shaft seal)..................................................................................................18
4.3.4Open design with adapter ring ...................................................................................................19
4.3.5Closed design with hub bearing, shaft seal and keyless hub.......................................................20
4.3.6Gearbox – fit ..............................................................................................................................21
4.3.7Closed design with hub bearing, shaft seal and clamping hub ...................................................22
4.4Output........................................................................................................................................24
4.4.1Version with belt output .............................................................................................................24
4.4.2Version with coaxial output ........................................................................................................24
4.4.3Version with TSC........................................................................................................................24
4.5Electrical connection, gear change.............................................................................................24
4.5.1Shift unit ....................................................................................................................................24
4.5.2Control logic...............................................................................................................................27
4.6Lubrication .................................................................................................................................28
4.6.1Splash lubrication.......................................................................................................................28
4.6.2Recirculating lubrication.............................................................................................................28
4.6.3Ports and connections for lubrication .........................................................................................30

Contents
4 EN 4161.758.101m – 2018-09
5Taking into Operation ..........................................................................................................32
5.1Initial inspection ........................................................................................................................ 32
6Maintenance ........................................................................................................................32
6.1Oil change................................................................................................................................. 32
7Repair ..................................................................................................................................33
7.1Gearbox fault checklist .............................................................................................................. 33
7.2Gearbox – disassemble ............................................................................................................. 34
7.3Input hub with fitted key............................................................................................................ 34
7.4Disassembly of gearbox with clamping hub............................................................................... 35
8Frequently Asked Questions (FAQ) ......................................................................................36

Preface
EN 4161.758.101m – 2018-09 5
1Preface
In addition to the ZF documentation, observe the
provisions of the body manufacturer.
1.1 Validity and field of application
This documentation applies to the following ZF
products:
2K120
2K121
1.2 Service products
Product Name/specification Quantity
(approx.)
[dm3]
Use Remarks
Grease Shell Avania WR2
Fuchs Renolit CXEP2
Esso Beacon EP2
General
assembly aid
Gearbox oil
HLP 68 according to
ISO VG 68 1.0
1.4
Gearbox oil for
splash lubrication
2K120 –
Installation position
B5
2K121 –
Installation position
B5
Can also be used for
recirculating lubrication
and recirculating
lubrication with heat
exchanger
Gearbox oil
HLP 46 according to
ISO VG 46
Gearbox oil for
recirculating
lubrication
Can also be used for
recirculating lubrication
with heat exchanger
Gearbox oil
HLP 32 according to
ISO VG 32
Gearbox oil for
recirculating
lubrication with
heat exchanger
Bonding agent
(liquid seal)
Loctite 574 Sealing end cover
in hub
End disc 28 DIN 470 1 Hub sealing Exchange after
disassembling the hub

Safety
6 EN 4161.758.101m – 2018-09
2Safety
2.1 Signal words and symbols
This document contains specifically highlighted
safety instructions which are marked with one of
the following signal words depending on the
severity of the danger.
DANGER
The signal word DANGER indicates a dangerous
situation that, if not prevented, will lead to a
severe injury or death.
Information as to how the hazard can be
prevented.
WARNING
The signal word WARNING indicates a
dangerous situation that, if not prevented, can
lead to a severe injury or death.
Information as to how the hazard can be
prevented.
CAUTION
The signal word CAUTION indicates a
dangerous situation that, if not prevented, can
lead to a slight or moderate injury.
Information as to how the hazard can be
prevented.
The signal word NOTE indicates a situation that,
if not prevented, can lead to property damage.
Information as to how the property damage
can be prevented.
The following symbols are also used:
This symbol refers to additional, safety-
relevant information.
This symbol indicates information
concerning special workflows, methods,
application of auxiliary materials, etc.
2.2 General safety instructions
Read all safety instructions and information.
Failure to comply with safety instructions and
information may lead to property damage, serious
injuries or death.
Intended use
The ZF product is exclusively intended for the
application as defined in the contract and as
agreed on at the time of delivery. Any other or
more extensive form of use does not comply with
this definition of intended use. The intended use
includes compliance with this documentation and
other applicable documents, in order to avoid
malfunctions and damage in operation.
The ZF product is designed and produced in line
with state-of-the-art technology. The ZF product is
safe to operate in its delivery status. However, the
ZF product may pose dangers if improperly used
by unauthorized, untrained and uninstructed staff
or if not used according to its intended use.
Figures might deviate from the ZF product and are
not drawn to scale. No conclusions can be drawn
with regard to size and weight.
Assembly, commissioning, maintenance and
repair
Only perform assembly, commissioning,
maintenance and repair work according to this
documentation and other applicable documents.

Safety
EN 4161.758.101m – 2018-09 7
Observe the following points:
Employ authorized, trained and instructed staff.
Observe technical provisions.
Only use genuine ZF spare parts.
Only use genuine ZF accessories.
Only use genuine ZF special tools.
Unauthorized changes and modifications lead to
the expiry of the operator's license, warranty or
guarantee.
In case of damage, contact ZF and have the
following information on the product to hand:
Type
Parts list [BoM] number
Serial number
Kilometer reading
Description of damage
Observe safety instructions, valid safety regulations
and legal requirements to prevent malfunctions
and damage.
The country-specific safety regulations, accident
prevention regulations and environmental
protection provisions also apply.
Wear workwear in accordance with safety
requirements for all work. Depending on the work,
also wear personal protective equipment.
After completing the work, check correct function
and functional security.
Handling of ZF product
Unauthorized changes and modifications may
impair functional security.
Changes, modifications and applications are only
permitted with the written approval of ZF
Friedrichshafen AG.
Observe the following when working on the ZF
product:
Secure workspace.
Only carry out work at the unit when in a
voltage-free state.
Protect unit against being started accidentally.
Attach information sign in a clearly visible
position.
Perform work when motor is switched off.
Protect motor against being started accidentally.
Attach information sign in a clearly visible
position.
Do not stand beneath a suspended load.
Do not work on a suspended load.
Only use permitted means of transport and
lifting appliances with sufficient load-bearing
capacity.
Close open pipelines and hoses and avoid
damage.
Observe tightening torques.
Protect cables against mechanical damage.
Noise
Noise may cause irreversible damage to hearing.
The perception of acoustic signals, warning calls
or sounds warning of impending danger is
impaired by noise.
Observe the following when working on the ZF
product:
Avoid noise.
Wear ear protection.
Operating supplies and auxiliary materials
Operating supplies and auxiliary materials may
cause permanent damage to health and
environmental damage.
Observe the following when selecting operating
supplies and auxiliary materials:
Health risks
Environmental compatibility
Material safety data sheets
Observe the following when handling operating
supplies and auxiliary materials:
Store operating supplies and auxiliary materials
in suitable and correctly labeled containers.
Seek medical help in case of injuries due to hot,
cold or caustic operating supplies or auxiliary
materials.
Observe the following to protect the environment:
Collect leaking operating supplies and auxiliary
materials in containers of a sufficient size.
Observe disposal regulations.
Observe material safety data sheets.

Safety
8 EN 4161.758.101m – 2018-09
2.3 Product-specific safety instructions
Remove any traces of old seals or gaskets from
mating faces. Burrs or other similar rough
surfaces are to be carefully removed with an oil
stone.
Carefully cover opened gearboxes to prevent
the entry of foreign matter.

Application and Design
EN 4161.758.101m – 2018-09 9
3Application and Design
3.1 Application
The ZF-DUOPLAN two-speed gearbox is mainly
used in machine tool drives.
By way of example, the gearbox can be used in
turning machines (horizontal B5) or machining
centers (vertical V1) thanks to its variable
installation position. The gearbox is also suitable
for use in many systems in which torque increase
or speed reduction is required.
The gearboxes have coaxial output and are
suitable for the high speeds generated in machine
tool construction.
3.2 Features
Two-speed gearboxes for AC and DC main
spindle drives in machine tools
Compact thanks to planetary design
Flange-mountable to all AC, DC and standard
motors
High running smoothness and low-noise
operation thanks to helical gearing
Low torsional backlash
Easy to install
High radial forces permitted on output end
Combined axial and radial force thanks to
flexible output bearings
High efficiency
Electromotive gear change

Application and Design
10 EN 4161.758.101m – 2018-09
3.3 Design
The gearbox primarily comprises the following
assemblies:
Connecting parts:
Drive hub (1)
Adapter plate (2) with radial shaft seal (3) and
hub bearings (4), as necessary
Housing:
Gearbox housing (5)
Input:
Sun gear (6)
Ring gear (7)
Ring gear bearings (8)
Output:
Bearing housing (9)
Output bearings (10, 11)
Output shaft (12)
Radial shaft seal (13)
Planet carrier (14)
Sun gear bearings (15)
Shift mechanism:
Sliding sleeve (16)
Shift fork (17)
Brake disc (18)
Shift unit:
Shift unit (19)
Selector finger (20)

Application and Design
EN 4161.758.101m – 2018-09 11
3.4 Technical data
Nominal power max. 19 kW
Nominal speed 1,500 rpm
Input torque
(continuous operation): max. 120 Nm
Max. speed
in ratio i1 8,000 rpm
in direct drive i=1
(with gearbox oil cooling) 12,000 rpm
See chap. 4.6.3.2 “Connections for circulating
lubrication” (Values apply as of 01/2004).
When using engine brakes/counterflow to
brake the spindles (e. g. emergency stop)
ensure that the moments of inertia do not
exceed the admissible output torques.
Braking times must be adjusted
accordingly.
Standard fixing dimension (in mm)
in accordance with EN 50347:2001
Two-speed
gearbox
2K120
FF215
2K121
FF265
Motor size 100 112
h 100 112
d 28/32/38 28/32/38
l 80±0.1 80±0.1
b 180 230
e2215 265
a1– –
s214 14
Nominal input torque 
(continuous operation) max. 120 Nm
Max. output torque for
i = 1.00 120 Nm
i = 3.16 379 Nm
i = 4.00 480 Nm
i = 4.91 589 Nm
Weight approx. 42 kg (2K120)
approx. 52 kg (2K121)
Model plate (standard)
(affixed to gearbox housing)
ZF FRIEDRICHSHAFEN AG
MADE IN GERMANY
TYPE PARTS LIST
RATIO SERIAL-NO.
BACKLASH
MAX.
INPUT TURN RPM
POWER MAX.
AT RPM KW
INPUT
TORQUE NM OIL GRADE
OIL
QUANTITY
SHITING V
UNIT W
i , - ,
MIN.

Application and Design
12 EN 4161.758.101m – 2018-09
3.5 Installation positions
Horizontal B5
Horizontal B5
Shift unit on right side
Gearbox turned around longitudinal axis
(view to output end)
Vertical V1
Vertical V3
Possible damage to gearbox due to oil
leaks.
The breather outlet must always be at the
top, regardless of the installation position.

Initial Installation
EN 4161.758.101m – 2018-09 13
4Initial Installation
4.1 Axial runout, radial runout and length
tolerances – drive motor
In order to guarantee fault-free operation, the
motor must not exceed the specified tolerances.
Axial runout, radial runout and length tolerances –
electric motor mounting flange:
Gearbox
type
Tolerance
A B C
L
2K120/
2K121
0.025 0.050 0.050 ± 0.100
Tolerances A, B, C according to DIN 42955R
Please note that the tolerance of the shaft length
“L” is restricted in relation to the DIN standard
The gearbox function will be impaired by
incorrect tolerances.
Comply with tolerance of shaft length “L”.
The special tolerance for shaft length “L” must be
maintained in order to guarantee fault-free
gearbox operation. Undersize shafts must be
compensated for by using shims when mounting
to the motor. Oversize shafts must be machined to
the correct length.
Take into account the permitted axial forces on the
motor shaft. Also see ZF-DUOPLAN catalog
(4161.750.102), “Performance data” chapter.
Take into account the motor shaft elongation
caused by heating in motors with fixed bearing on
the B-side (opposite the motor output shaft).
ABC
L
001064

Initial Installation
14 EN 4161.758.101m – 2018-09
Semi-key balancing Full-key balancing
4.2 Balancing
If using motors with parallel keys, note
the balancing type.
The hubs (2) come with a keyway (1) for
transmitting power from the motor shaft (3) as
standard.
There are two balancing types for the motor and
gearbox: semi-key and full-key, which are
described in more detail in DIN ISO 8821.
It must be ensured that the hub is balanced in the
same way as the motor.
This is why it is very important to indicate the
motor data, dimensions and balancing type when
ordering.
Motor output shafts with standard fitted key in
accordance with EN 50347:2001
Shaft diameter Fitted ke
y
Fitted key
length
28 mm A7x7 45 mm
32/38 mm A10x8 70 mm
42 mm A12x8 90 mm
48 mm A14x9 90 mm
In the case of motor shafts with open ends
of the keyway, the parallel key is to be
glued into the groove in order to avoid axial
migration of the parallel key and/or the hub.
Clamping hubs are used for motors without
parallel keys. A balancing type is not required.
4.2.1 Semi-key balancing
In semi-key balancing, the keyway is filled with
a balance compensation corresponding to
approximately half a key, shape B by default. This
is based on the original key, shape, length and
position used by the motor manufacturer and is
defined as a counterweight. In semi-key balancing
– in contrast to full-key balancing – the joint
passes through a shared component. This means
imbalance can arise after assembly due to
tolerance factors.
As a result, it is recommended that rebalancing
should be performed after the joined parts have
been assembled.
4.2.2 Full-key balancing
In full-key balancing, the motor shaft is balanced
with a full key whereas the hub is not. The parallel
key, shape, length and position are not important
in this case.
1
2
3

Initial Installation
EN 4161.758.101m – 2018-09 15
4.2.3 Motor shafts/hubs without keyways
Clamping hubs are available for motor shafts with
diameters of 38 mm, 42 mm and 48 mm.
1Hub
2Motor shaft

Initial Installation
16 EN 4161.758.101m – 2018-09
4.3 Adaptation, motor/gearbox
The motors must have a flange-mounting option
for mounting the gearboxes.
The gearbox housing is fitted to the motor by
means of the centering adapter on the bearing
housing. This is standard.
There is also a foot mounting on the gearbox
housing for 2K120.
Different gearbox variants are used depending on
the motor type. Gearbox mounting also differs
accordingly.
Reference dimensions for hub position
Gearbox type Dimension C in mm
2K120 33.3-0.2
2K121 53.3-0.2
In the case of motors with fixed bearing, on the B
side, the dimension is C = 32.8-0.2 (2K120) or
52.8-0.2 (2K121).
4.3.1 Open design
The open version is the gearbox without adapter
plate but with seal on the motor output shaft (2) to
prevent gearbox oil ingress.
The drive hub (1) is delivered loose with the
gearbox. Clean the fitting surfaces of the motor (3)
and drive hub. Check the motor shaft for
concentricity, axial runout and length according to
chapter 4.1. Also lightly grease the motor shaft.
Risk of burns due to contact with hot surfaces.
Slight to moderate injury possible.
Wear protective gloves.
After cleaning the fitting surfaces, heat the drive
hub to approx. 120 °C from the opening and slide
it onto the motor shaft until it reaches the stop.
Risk of motor shaft damage if the drive hub is
not sufficiently heated.
Heat drive hub to approx. 120 °C.
Tighten the threaded pin (9) and secure it to
prevent it from turning, see chap. 4.3.6.

Initial Installation
EN 4161.758.101m – 2018-09 17
4.3.2 Closed design with hub bearing and
shaft sealing ring
Variant with ball bearing (4), in which the hub (1)
is also mounted in bearings to ensure easy
installation. No parts need to be measured and
shims are no longer required, since the hub is
supplied with the adapter plate and hub bearings
already in the correct position.
No internal axial forces occur with 2K120/2K121
that can affect the hub.
When assembling, separate the drive hub (1) with
adapter plate (5) from the gearbox housing (6).
Clean the fitting surfaces of motor and drive hub.
Check the motor shaft for concentricity, axial
runout and length according to chapter 4.1. Also
lightly grease the motor shaft.
Risk of burns due to contact with hot surfaces.
Slight to moderate injury possible.
Wear protective gloves.
After cleaning the fitting surfaces, heat the drive
hub to approx. 120 °C from the opening and slide
it onto the motor shaft until it reaches the motor
flange stop.
Reference dimension “C” is set at the factory.
Risk of motor shaft damage if the drive hub is
not sufficiently heated.
Heat drive hub to approx. 120 °C.
When assembling, it must be possible to easily
slide the hub onto the motor shaft until the
adapter plate is against the motor flange.
Do not use the adapter plate to help slide
the hub onto the motor shaft.
Check by ensuring that the fitted adapter plate can
be turned freely. This ensures that there is no hub
bearing preload.
Tighten the threaded pin (9) and secure it to
prevent it from turning, see chap. 4.3.6.
The radial shaft sealing ring in the drive motor
must be removed on the output end when the
closed design is used.
3
10
9
1
2
5
6
11
C
7
4

Initial Installation
18 EN 4161.758.101m – 2018-09
4.3.3 Closed version
(with shaft seal)
This variant incorporates an adapter plate (5) with
shaft seal (7), which means that the gearbox forms
a compact, closed unit.
The adapter plate and drive hub (1) are delivered
separately and loose. Clean the fitting surfaces of
the motor (3) and drive hub. Check the motor shaft
(2) for axial and radial runout as described in
chapter 4.1. Also lightly grease the motor shaft.
Risk of burns due to contact with hot surfaces.
Slight to moderate injury possible.
Wear protective gloves.
After cleaning the fitting surfaces, place the
adapter plate with radial shaft seal onto the motor
housing. Heat the drive hub to approx. 120 °C
from the opening and slide it onto the motor shaft
until it reaches the stop, using shims (13) if
required.
Then check reference dimension “C” and change
using shims if necessary.
Risk of motor shaft damage if the drive hub is
not sufficiently heated.
Heat drive hub to approx. 120 °C.
Tighten the threaded pin (9) and secure it to
prevent it from turning, see chap. 4.3.6.
Thoroughly grease the radial shaft seal and
the drive hub before installation. When
installing, make sure that the sealing lip
and the radial shaft seal are in the correct
position.
The radial shaft sealing ring in the drive motor
must be removed on the output end when the
closed design is used.
310
12
13
7
5
6
11
C

Initial Installation
EN 4161.758.101m – 2018-09 19
4.3.4 Open design with adapter ring
The adapter ring allows adaptation to different
connecting dimensions. A seal is required on the
motor output shaft.
The adapter ring (5) and drive hub (1) are
delivered loose. Clean the fitting surfaces of the
motor (3) and drive hub. Check the motor shaft (2)
for axial and radial runout as described in chapter
4.1. Also lightly grease the motor shaft.
Risk of burns due to contact with hot surfaces.
Slight to moderate injury possible.
Wear protective gloves.
After cleaning the fitting surfaces, place the
adapter ring onto the motor housing. Then heat
the drive hub to approx. 120 °C from the opening
and slide it onto the motor shaft (2) until it reaches
the stop, using shims (13) if required.
Then check reference dimension “C” and change
using shims if necessary.
Risk of motor shaft damage if the drive hub is
not sufficiently heated.
Heat drive hub to approx. 120 °C.
Tighten the threaded pin (9) and secure it to
prevent it from turning, see chap. 4.3.6.
35
10
6
9
1
13
2
11
C

Initial Installation
20 EN 4161.758.101m – 2018-09
4.3.5 Closed design with hub bearing,
shaft seal and keyless hub
When mounting on motors with a smooth motor
shaft without a keyway, it is necessary to use ring
clamping elements and pressure pieces between
the motor shaft and the input hub in order to
transmit the torque. There must be a central
thread in the motor output shaft.
The mating surfaces of the motor (3), motor shaft
(2) and input hub (1) must be cleaned.
Check the motor shaft (2) for axial and radial
runout as described in chapter 4.1.
Loosely mount the counter-holder (4), ring
clamping elements (5+6), bush (12), pressure
piece (7) and screw connection with thread lock
(8) in advance. Watch out for the position of the
ring clamping elements when doing this. First
install the inner (5) then the outer (6) ring
clamping elements in the pack on the motor
shaft.
Push the input hub onto the motor shaft with or
without adapter plate (9), depending on the
version.
By hand, move the ring clamping elements into
contact using the screw connection. Tightening
the screw connection causes the hub (and the
adapter plate, if fitted) to move axially towards the
motor. Take this into consideration with a lead
dimension of +0.4 mm.
Tighten screw connection (8) to 90 Nm for M12.
Take note of the maximum torque permitted for
the thread in the motor shaft. Screws with a
strength category of 10.9 must be used with
adaptations without a coolant flow.
Check dimension C and the concentricity of the
hub.
There is no longer any need for an additional
internal seal in conjunction with ring clamping
elements. The number of ring clamping elements
and bushes can vary depending on the motor.
In screw connections with a hole for the coolant to
flow through, watch out for the O-rings and grease
them before installation.
The input hub must be blocked in order to prevent
twisting of the motor shaft and input hub when
tightening. This can be done using a special tool
ZF 1X46.190.227.
DO NOT GREASE the motor shaft (2) and
the hole in the input hub (1).
Lightly oil the cone surface of the ring
clamping elements (5+6).
The counter-holder is supported on the shoulder of
the motor shaft. It is necessary to have a large
contact surface.
In the closed version without hub bearing, grease
the seal running surface for the radial oil seal on
the input hub before installation. Watch out for the
position of the sealing lip when pushing on the
input hub.
When using the enclosed design with hub
bearing (10) and radial oil seal (11), do not
push the input hub onto the motor shaft
using the adapter plate. Once the screw
connection has been tightened, the adapter
plate must be in contact with the motor
housing and it must be possible to turn it
freely. This means the hub bearing is free
from tension.
36
5
56
8
8
1
7
10
9
C
11
4
2