Special mechanisms mainly include: power takeoff, front and rear supports of mixing drum, reducer, hydraulic system, mixing drum, operating mechanism, cleaning system, etc.
Power take-off device: domestic concrete mixer truck adopts the power take-off mode of main vehicle engine. The function of the power take-off device is to take out the power of the engine by operating the power take-off switch, drive the mixing drum through the hydraulic system, and the mixing drum rotates forward during feeding and transportation, so as to facilitate feeding and mixing of concrete, rotate reversely during discharging, and cut off the power connection with the engine after the end of work.
Hydraulic system: convert the engine power taken out by the power take-off (now generally rear full-function power take-off) into hydraulic energy (displacement and pressure), and then output into mechanical energy (speed and torque) through the motor to provide power for the rotation of the mixing drum.
Reducer: after decelerating the speed output by the motor in the hydraulic system, it is transmitted to the mixing drum.
a. Control the rotation direction of the mixing drum to make it rotate forward during feeding and transportation and reverse during discharging.
b. Control the rotating speed of the mixing drum.
Mixing device: it is mainly composed of mixing drum and its auxiliary supporting parts. The mixing drum is a concrete loading container, which is made of high-quality wear-resistant steel plate. In order to automatically load and unload concrete, its inner wall is welded with spiral blades of special shape. When rotating, the concrete moves along the spiral direction of the blade and is mixed and stirred in the process of continuous lifting and turning. During feeding and transportation, the mixing drum rotates forward, and the concrete moves inward along the blade. When discharging, the mixing drum reverses, and the concrete is discharged outward along the blade.
The rotation of the mixing drum is guaranteed by the hydraulic driving device. The loading capacity is 3 ~ 6 cubic meters. Generally, the truck engine drives the hydraulic pump through the power output shaft, and then the high-pressure oil drives the hydraulic motor to drive the mixing drum. For the truck with a loading capacity of 9 ~ 12 cubic meters, the on-board auxiliary diesel engine drives the hydraulic pump to drive the hydraulic motor. Blade is the main component of mixing device. Damage or serious wear will lead to uneven mixing of concrete. In addition, if the design of blade angle is unreasonable, the concrete will be separated.
Cleaning system: the main function of the cleaning system is to clean the mixing drum, and sometimes it is also used for dry material mixing during transportation. The cleaning system also cools the hydraulic system.