The concrete mixer truck is composed of truck chassis and special equipment for concrete mixing and transportation. The chassis of concrete mixer truck produced in China mostly adopts class II general chassis provided by vehicle manufacturers. Its special mechanism mainly includes power take-off, front and rear support of mixing drum, reducer, hydraulic system, mixing drum, control mechanism, cleaning system, etc. Its working principle: the power of the automobile chassis is taken out by the power take-off device, and the variable pump of the hydraulic system is driven. The mechanical energy is converted into hydraulic energy and transmitted to the quantitative motor. The motor drives the reducer, and the reducer drives the mixing device to mix the concrete.
1.1 power take-off device
The main engine power take-off mode is adopted for domestic concrete mixer truck. The function of the power take-off device is to take out the power of the engine by operating the power take-off switch, and drive the mixing drum through the hydraulic system. The stirring drum rotates forward in the process of feeding and transportation to facilitate the feeding and mixing of concrete. It rotates reversely when discharging, and cuts off the power connection with the engine after the end of the work.
1.2 hydraulic system
The engine power taken out by the power take-off device is converted into hydraulic energy (displacement and pressure), and then the motor outputs mechanical energy (speed and torque) to provide power for the rotation of the mixing drum.
After decelerating the speed of the motor output in the hydraulic system, it is transmitted to the mixing drum.
1.4 control mechanism
a. Control the rotation direction of the mixing drum to make it rotate forward in the process of feeding and transportation, and reverse rotation when discharging.
b. Control the speed of mixing drum
1.5 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 thin 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 mixed in the process of continuous lifting and turning. In the process of 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 ensured by the hydraulic driving device. The concrete mixer truck with a loading capacity of 3-6 cubic meters generally adopts the hydraulic pump driven by the automobile engine through the power output shaft, and then the mixing drum is driven by the hydraulic motor driven by the high-pressure oil. For the concrete mixer truck with the loading capacity of 9-12 cubic meters, the hydraulic pump driven by the auxiliary diesel engine is used to drive the hydraulic motor. Blade is the main part of the mixing device, damage or serious wear will lead to uneven mixing of concrete. In addition, if the angle of blade is not reasonable, it will cause concrete segregation.