The hydraulic retarder is also called a hydraulic speed reducer. The truck uses exhaust brakes when it is downhill, although it can receive good braking effect, but for mining dump trucks with large tonnage, the exhaust braking effect is limited, and the engine has a certain degree. Damage. Therefore, the mine dump truck equipped with the hydraulic mechanical transmission is equipped with a hydraulic deceleration retarder.

The stator of the hydraulic retarder is again a retarder housing connected to the rear end of the transmission or the frame. The rotor is connected to the transmission shaft through a hollow shaft, and the rotor and the stator are cast with blades. In operation, pressure is applied to the oil sump by the operation of the control valve to fill the working fluid between the rotor and the stator. When the rotor rotates, a torque is applied to the stator through the working fluid, and the counter torque of the stator becomes the braking torque of the rotor. The value depends on the liquid volume and pressure in the working chamber (depending on the braking intensity set by the control valve) Depending on the gear position, as well as the speed of the rotor. The kinetic energy of the automobile is converted into heat energy by the friction of the working fluid and the impact on the stator, so that the temperature of the working fluid rises. The working fluid is introduced into the heat exchanger to circulate, transferring heat to the cooling water and then dissipating through the engine cooling system. In the case of a hydraulic transmission vehicle, the oil pool, the oil pump, the heat exchanger (the size needs to be enlarged) and the working fluid using the hydraulic transmission can be omitted, and thus the hydraulic retarder is mostly used in the hydraulic transmission vehicle.

First of all, the hydraulic retarder is almost wear-free. The brake is to rub two solid pieces together, and the hydraulic retarder is rubbed with liquid - the equivalent of water skiing.

Secondly, not only downhill, but almost all deceleration can be achieved with a hydraulic retarder. It is another form of braking.

Finally, using a hydraulic retarder may keep the engine at a higher speed, but at this point it is not expensive. The deceleration phase does not inject oil.

Common retarder brands

Voith

SINOTRUK, FAW and other brands use Voith's hydraulic retarders when using their own gearboxes. At the same time it is also the supplier of Mercedes-Benz, the originator of the hydraulic retarder.

ZF

The ZF gearbox is basically equipped with its own liquid retardation. The manual transmission of SITRAK, AMT's FOTON EST, JAC K7, etc. are all such a match.

FAST

Just like ZF, it matches the gearbox of their own gearbox.

Scania

Scania's retarder is really the best solution for my trial experience. After putting it in the automatic mode, pressing the brake pedal will automatically coordinate the hydraulic retarder, brake, and engine brake, which is very worry-free.