
Service Training
BW 156/177 D-3/PD-3
- F 6 -
BW 178/179 D-3/PD-3
When turning the steering wheel the oil flow from the pump is guided through the distributor valve to the
rating pump and from there to the respective steering cylinders.
The rating pump determines the exact oil quantity in dependence on the turning angle of the steering
wheel.
The high pressure relief valve in the steering unit limits the pressure in the steering system to 175 bar
+ charge pressure.
The steering unit is fitted with so-called shock valves in each pressure side to the steering cylinders.
These valves are adjusted to 240 bar. The valves compensate extreme pressure peaks which may
occur, e.g. when driving over obstructions, and protect the system against overloads.
Each of these shock valves has its additional anti-cavitation valve. This anti-cavitation valve prevents
the appearance of cavitation, which may be caused by the response of the shock valves.
A check valve near the inlet port of the steering unit makes sure that no hydraulic oil will flow back to the
steering pump if the machine is articulated by sudden external forces. In such a case the steering
cylinders would try to work as pumps and deliver the oil back to the pump.
Summary of Contents for BW 156 D-3
Page 143: ...Service Training BW 156 177 D 3 PD 3 G 2 BW 178 179 D 3 PD 3 Supply Fig 1 Power supply...
Page 152: ...Service Training BW 156 177 D 3 PD 3 G 11 BW 178 179 D 3 PD 3 Brakes Fig 5 Brake...
Page 159: ...Service Training BW 156 177 D 3 PD 3 G 18 BW 178 179 D 3 PD 3 Vibration Fig 7 Vibration...
Page 187: ......
Page 188: ......
Page 189: ......
Page 190: ......