What is the reason why the steering wheel of small mixer truck is too heavy
What is the reason why the steering wheel of small mixer truck is too heavy to move?
The small mixer with hydraulic steering system has common and complex faults due to heavy direction, deviation, shaking and so on. The repairman is also difficult to eliminate. He is often uncertain about the cause of the fault, so he adopts the method of replacement test. In this way, the steering engine booster pump will inevitably become a test object or innocent victim. This is particularly evident in the Three Guarantees service. The return rate remains high, which has brought great losses to dealers and manufacturers. Therefore, this paper introduces the performance, working principle and troubleshooting methods of automobile hydraulic steering system to the majority of users.
The steering power pump of small-scale mixer is usually called steering engine power pump. It is not only the power source of the steering power system of obstacle removal vehicle, but also the heart of the steering system. For heavy-duty obstacle removal vehicles, the hydraulic steering system is more important because of the mechanical steering machine and the high labor intensity of the driver.
The steering machine booster pump commonly used in small mixer truck is divided into blade type and gear type.
Here will focus on the vane steering engine booster pump.
The general vane pump consists of a grooved rotor with double circular arc curve in the inner cavity Composed of blades and other parts. Some are installed on the flywheel housing at the rear end of the engine and are also driven by timing gears. When the engine is running, it drives the rotor of the booster pump to rotate. Under the action of centrifugal force, the blade moves outward along the blade groove and close to the inner wall of the pump body. In the process of rotor rotation, due to the continuous increase and decrease of the closed volume between the blades, the process of oil absorption and oil pressure is realized. The rotor completes oil suction and oil pressure twice every revolution. There is also a safety valve in the pump body to limit the maximum pressure. When the external load of the steering system increases, causing the oil pressure to rise to a certain value, the safety valve opens to unload the load. A throttle valve and a flow control valve are also installed in the pump body to ensure that the displacement of the booster pump is basically stable.
The use and maintenance of steering engine booster pump is particularly important. Therefore, the following points must be achieved:
I Correct selection of hydraulic oil is the key to ensure high efficiency and prolong service life of booster pump.
II Regularly check the oil level of the oil storage tank. If it is insufficient, add clean hydraulic oil in time. The filter element in the oil storage tank should be cleaned with alcohol during maintenance.
III In case of leakage, impact or abnormal noise of steering engine booster pump during use, it shall be checked and eliminated in time.
IV After the small mixer truck has been running for a period of time, the filter elements of the hydraulic oil should be replaced in time, especially after the new pump is loaded and used for 2500-3000 kilometers, the hydraulic oil should be replaced.
The oil change method is as follows:
1. Support the front axle and keep the wheels off the ground.
2. Remove the oil storage tank cover, remove the oil return pipe and the oil drain plug of the steering gear.
3. Start the engine and run it at high speed for about 10 minutes to drain the hydraulic oil in the oil storage tank, steering engine booster pump and steering engine.
4. Stop the engine, turn the steering wheel left and right to the limit position, and drain all the residual hydraulic oil.
5. Replace the filter element, add hydraulic oil to the specified height, and exhaust the air of the hydraulic system.