Kalmar ContChamp DRD S Series, Technical Handbook

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ContChamp DRD-S
Technical Handbook
Main hydraulics
Description
3 S. Grupp 70
9407
04-10
Overview
The numbers in the text preceded by an H, for example, H13, re-
fer to the hydraulic system diagram. The numbering in the differ-
ent illustrations is common with the hydraulic system diagram.
The hydraulic system consists of the following sub-systems:
z Working hydraulics that include:
– Servo hydraulics that supply pressure to the electro-hy-
draulic servo system
– Extension and retraction of the boom
– Lift and lowering of the boom
z Attachment hydraulics (see group 80)
– Rotation of the yoke (hydraulic motor)
– Length adjustment of top-lift (hydraulic motor)
– Side-shift of top-lift
– Locking/release of twist-locks
z Foot brake system
– WDB system, hydraulically controlled, oil-cooled multiple
brake discs with external cooling
z Parking brake system, disk brake on the drive axle's ingoing
axle, spring activated with hydraulic release.
z Steering system
Electro-hydraulic servo system, principles
The working hydraulics are controlled via an electro-hydraulic
servo system, the principle components of which are illustrated
on the next page.
All hydraulic system functions are controlled via three independ-
ent sub-systems:
– El-servo
– hydraulic-servo
– working hydraulics
The el-servo system is controlled by the ECU2 central computer
unit as part of the truck's ECS system. Descriptions of the servo
circuits can be found in group 20, under the ECU2 section.
From ECU2, digital or analogue signals are fed to the control le-
ver. The signals are affected by the degree of movement of the
control lever, after which they are fed back to and processed in
ECU2.
The out-signals for LIFT/LOWER and BOOM OUT/IN from ECU2
are fed to converters (H14 and H15) on the main valve H16. The
converters are electrically controlled pressure reduction valves
that convert the electrical signal to a proportional hydraulic pres-
sure - servo pressure.
The servo pressure affects the control slide in the main valve for
the function in question and from there, the main flow.
Main valve 13 has no converter but obtains its servo pressure
from the converter for the main valve 16.
The pressure regulator valve for the servo circuit obtains its hy-
draulic pressure from pump 2 and provides 30-35 bar servo pres-
sure to the converters on the main valves of the truck and
attachments and for release of the parking brake.