Mechanical Technology

Mechanical Technology — October 2015

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Hydraulic and pneumatic systems

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he IndraDrive Mi merges its

drive electronics and motors/

servomotors into an integral

unit. This combination, which

can also comprise I/O units and pneu-

matic and hydraulic actuators, virtu-

ally eliminates drive electronics housed

within a cabinet and drastically reduces

the wiring required to connect the indi-

vidual components. With an integrated

drive control unit from Bosch Rexroth,

drive functions, motion control and flow

logic merge into an open automation

platform. Complex motion tasks can be

handled with the motion logic system,

which is fully designed in accordance

with IEC 61131-3.

“The cabinet-free drive technol-

ogy extends the possibilities in modu-

larising machine concepts,” explains

Cabinet-free hydraulic drive control

Hydrostatic and planetary drive combination

osch Rexroth’s HYDROTRAC

GFT 8000 drive enables an ap-

proximate 10% increase in drive

train performance for larger mobile working

machines. Launched earlier this year and

now available from Hytec, a Hytec Group

Company, these transmission units are

based on a modular design. Ideal for use

in harsh, rugged environments including

African mining operations,

they have two- and three-stage

combined planetary gearing

driven by axial piston motors

to match the needs of heavy and

bulky mobile working machines

such as trucks and excavators.

An optional internal brake

reduces the installation space

needed, but adheres to the

safety specifications for world-

wide roadworthiness certifica-

tion. The mechanical planetary

drives in these transmission units trans-

fer the torque from the hydrostatic drive

to the wheels or tracks. Bosch Rexroth

uses the newest versions of variable axial

piston motors or fixed-displacement axial

piston motors, which operate in either an

open or closed circuit mode.

Travel capacity is significantly improved

as the higher fluid capacity of the motors

and the higher hydraulic pressures, along

with exact matching with the two- and

three-stage planetary drives, boost torques

and therefore performance by approxi-

mately 10%.

At the same time, vehicle manufactur-

ers can sometimes select a smaller nomi-

nal size to achieve the same output. This

saves installation space.

The optional integrated multi-disk

brake inside the unit requires minimal

maintenance and is designed for protec-

tion against soiling, an added advantage

when working in demanding environments.

Also, when used in conjunction with Bosch

Rexroth’s high level braking system, they

satisfy the exacting safety requirements for

speeds up to 50 km/h.

All units are delivered as complete

assemblies, ready for installation, and

vehicle manufacturers can select a

smaller nominal size to achieve

the same output, which also

saves on installation space.

Due to the platform’s modular

concept, OEMs can vary the

drive torques and transmission

ratios, closely matching them

to the vehicle used.

Two models in the 8000

series, which achieve nominal

torques of 20 and 30 kNm, are

available off-the-shelf and an ad-

ditional seven models are currently

being rolled out to the market.

Reallocating control functions to the individual machine modules allows

machine engineers and operators to make maximum use of valuable

site space, enhancing their production capacities. The cabinet-free drive

technology IndraDrive Mi from Bosch Rexroth is enabling this idea to be

implemented in automation applications across numerous industries and

production sites.

Georg Venter, divisional manager, Tectra

Automation. “Machine manufacturers

pre-assemble machine modules and

then connect them to one another at the

cabinet without any further work.”

Central to the reallocation of drive

control components are the Bosch

Rexroth decentralised supply and mains

modules. “This is how machine manufac-

turers can integrate all drive components

directly into the machine without needing

a cabinet,” Venter adds.

The mains module includes a mains

filter, mains regulator and mains protec-

tion in a single unit. The supply module

includes an energy-recovering power

supply, control electronics and brake

resistors. The connection of the machines

or modules to the power supply is carried

out directly and without deviation via

the cabinet. This reduces wiring in the

assembly by as much as 90%.

A newly developed hybrid plug for

adjacent near-motor drives further re-

duces assembly work. These protected

connector pieces for communication and

power supply are simply plugged into

adjacent IndraDrive Mi units by assembly

technicians.

IndraDrive Mi supports all of com-

mon Ethernet-based protocols, including

ProfiNet, EtherNet/IP and EtherCAT, all

on a single piece of hardware with the

Multi-Ethernet interface via the automa-

tion bus Sercos. The hardware remains

identical, with selection occurring purely

via software parameters. A connection

to Profibus can be created via Gateway.

The motor-integrated and near-motor

drive modules are designed in accor-

dance with IP65-class protection for dust

and water stream protection.

Up to 20 IndraDrive Mi modules can

be connected in series in a cable harness

up to 200 m long. The drive-based con-

trol by Bosch Rexroth coordinates up to

nine IndraDrive Mi as slaves in real time.

The IndraDrive Mi cabinet free drive

technology is available in sub-Saharan

Africa through Tectra Automation, a

Hytec Group company.