S0607080K
Page 7
Transmission and Torque Converter
(ZF 4WG-310)
POWERSHIFT TRANSMISSION
The multispeed reversing transmission in countershaft design is power shiftable by hydraulically actuated
multidisk clutches.
All gears are constantly meshing and carried on antifriction bearings.
The gear wheels, bearings and clutches are cooled and lubricated with oil.
The 4-speed reversing transmission is equipped with 6 multidisk clutches.
At the shifting, the actual plate pack is compressed by a piston, movable in axial direction, which is
pressurized by pressure oil.
A compression spring takes over the pushing back of the piston, thus the release of the plate pack. As to
the layout of the transmission and the specifications of the closed clutches in the single speeds, See
“Schedule of Measuring Points and Connection 4WG-310” on page 8. and “Oil Circuit Diagram 4WG-310
Forward 1st Speed” on page 11.
TRANSMISSION CONTROL
Transmission control, See “Schedule of Measuring Points and Connection 4WG-310” on page 8., Electro-
hydraulic unit on page 10 and “Oil Circuit Diagram 4WG-310 Forward 1st Speed” on page 11.
The transmission pump, necessary for the oil supply of the converter, and for the transmission control, is
sitting in the transmission on the engine-dependent input shaft.
The feed rate of the pump is Q = 130
l
/min. at n
Engine
= 2000 min
-1
.
This pump is sucking the oil via the coarse filter out of the oil sump and delivers it via the ZF-Fine filter - the
filters is fitted externally from the transmission - to the main pressure valve.
ZF-Fine filter
Filtration ratio according to ISO 4572:
β
30
≥
75
β
15
= 25
β
10
= 5.0
Filter surface at least: 2 x 6,700 cm
2
= 13,400 cm
2
Dust capacity according to ISO 4572 at least: 17 g
The six clutches of the transmission are selected via the 6 proportional valves P1 to P6.
The proportional valve (pressure regulator unit) is composed of pressure regulator (e.g. Y6). follow-on
slide and vibration damper.
The control pressure of 9 bar (130 psi) for the actuation of the follow-on slides is created by the pressure
reducing valve. The pressure oil (16+2 bar (232+29 psi)) is directed via the follow-on slide to the respective
clutch.
Due to the direct proportional selection with separated pressure modulation for each clutch, the pressure
to the clutches, which are engaged in the gear change, will be controlled. In this way, a hydraulic
intersection of the clutches to be engaged and disengaged becomes possible. This is creating
spontaneous shifts without traction force interruption.
At the shifting, the following criteria will be considered:
• Speed of engine, turbine, central gear train and output.
• Transmission temperature.
• Shifting mode (up-, down-, reverse shifting and speed engagement out of Neutral).
• Load condition (full and part load, traction, overrun inclusive consideration of load cycles during
the shifting).
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