Truck & Off-Highway Engineering - December 2023 - 4

TECHNICAL
INNOVATIONS
ELECTROHYDRAULICS
'Electronification' of working hydraulics in compact machines
SAE INTERNATIONAL
BOARD OF DIRECTORS
Todd Zarfos
President
Carla Bailo
2024 President
Srinivasa (Sri) Srinath, Ph.D
2022 President
Susan Ying, Ph.D
Vice President - Aerospace
Daniel Nicholson
Vice President - Automotive
Audley Brown
Vice President -
Commercial Vehicle
Andrew Jeffers
Treasurer
David L. Schutt, Ph.D
Chief Executive Officer
Gregory L. Bradley, Esq.
Secretary
Sampierana debuted the Rexroth eOC architecture on its six-ton mini excavators, including the triple-boom 65TR
suitable for digging, handling and loading operations.
Compact off-highway machines should be as
maneuverable, versatile and energy-efficient as
possible. Key to achieving these goals is the
electronification of the working hydraulics. New
mini excavators, wheel loaders and track loaders
from the Eurocomach brand, which is part of
the Italian Sampierana Group, demonstrates the
improvements that can be gained by utilizing
electrohydraulic pump control and software.
Sampierana first launched the electronification
of its working hydraulics on its six-ton mini
excavators. " Our compact construction machines
are used for a wide variety of jobs, " said
Giuseppe Fabbri, technical manager at
Sampierana. " Loading, excavating or digging
should be very accurate or quick and productive
to perform, as needed, and also support a
wide range of tools - from shovels to hammers
or mowers. "
Conventional work hydraulics have limited
what could be done because their rigidity forces
manufacturers to compromise. Because it
used to be necessary to specify in advance
whether the hydraulic pump was to be controlled
by pressure, torque or swivel angle,
4 December 2023
it was not possible to optimize energy efficiency,
flexibility and productivity in equal measure.
Once parameters have been defined on the
hardware side, they remain unchanged over
the entire service life.
Electronic control in an open loop
The eOC (electronic open circuit) architecture
from Bosch Rexroth features an electrohydraulic
axial piston pump as its central component,
operating in an open circuit with a swivel angle
sensor and pressure sensors. The eOC pump is
electronically controlled in a closed loop so
that the required setpoints for torque, pressure
or volume flow can be controlled independently
of each other precisely and dynamically in
the range of milliseconds.
Using the associated BODAS eOC software,
parameters such as dynamics and power control
can be individually set, changed and combined
during operation. The control software
communicates via the CAN bus and can be
installed either on a BODAS eOC controller
from Bosch Rexroth or on a controller from a
third-party manufacturer.
Judy Curran
Mary Lee Gambone
Michael Weinert
Joan Wills
SAE International Sections
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SAE Members in a given area. For more
information, please visit sae.org/sections
or contact SAE Member Relations Specialist
Abby Hartman at abby.hartman@sae.org.
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Collegiate Chapters
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together on their campus and develop
skills in a student-run and -elected
environment. Student Members are vital
to the continued success and future of
SAE. While your course work teaches
you the engineering knowledge you
need, participation in your SAE Collegiate
Chapter can develop or enhance other
important skills, including leadership,
time management, project management,
communications, organization, planning,
delegation, budgeting, and finance. For
more information, please visit students.
sae.org/chapters/collegiate/ or contact
SAE Member Relations Specialist Abby
Hartman at abby.hartman@sae.org.
TRUCK & OFF-HIGHWAY ENGINEERING
SAMPIERANA

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Truck & Off-Highway Engineering - December 2023

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