3-18
Due to the direct proportional selection with separated pressure modulation for each clutch, the
pressures 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 shiftings without traction force interruption.
At the shifting, the following criteria are 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).
The main pressure valve is limiting the maximum control pressure to 16+2 bar and releases the
main stream to the converter and lubricating circuit.
In the inlet to the converter, a converter safety valve is installed which protects the converter from
high internal pressures (opening pressure 11+2 bar).
Within the converter, the oil serves to transmit the power according to the well-known
hydrodynamic principle (see torque converter, page 3-3).
To avoid cavitation, the converter must be always completely filled with oil.
This is achieved by a converter back pressure back-up valve, rear-mounted to the converter, with
an opening pressure of at least 4.3bar.
The oil, escaping out of the converter, is directed to a oil cooler.
The oil is directed from the oil cooler to the transmission and from there to the lubricating oil circuit,
so that all lubricating points are supplied with cooled oil.
In the electro-hydraulic control unit are 6 pressure regulators installed.
GEAR SELECTOR (DW-3)
GEAR SELECTOR (DW-3)
5)
5)
The gear selector is designed for the
mounting on the left side of the steering
column. The positions (speeds) 1 to 4 are
selected by a rotary motion, the driving
direction Forward (F)-Neutral (N)-Reverse
(R) by tilting the gear selector lever.
The gear selector is also available with
integrated kickdown push button.
For the protection from unintended start off,
a neutral interlock is installed.
Position N - Gear selector lever blocked in
this position.
Position D - Driving.
F
N
R
1
2
3
4
N
D
73033TM17
Summary of Contents for HL955
Page 557: ...7 6 MEMORANDUM MEMORANDUM ...
