The automatic mixer truck is mainly composed of mixing drum and its auxiliary supporting parts. The mixing drum is a loading container for concrete. It is made of fine wear-resistant steel sheet. In order to load and unload concrete automatically, the inner wall of the mixing drum is welded with spiral blades of special shape.

转动时混凝土沿叶片的螺旋方向运动，在不断的提升和翻动过程中受到混合和搅拌。在进料及运输过程中，搅拌筒正转，混凝土沿叶片向里运动，出料时，搅拌筒反转，混凝土沿着叶片向外卸出。搅拌筒的转动则是靠液压驱动装置来保证。

When it rotates, the concrete moves along the spiral direction of the blade, and is mixed and stirred 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 blades. When discharging, the mixing drum reverses and the concrete is discharged outward along the blades. The rotation of the mixing drum is ensured by the hydraulic driving device.

装载量为3～6立方自动上料搅拌车一般采用由汽车发动机通过动力输出轴带动液压泵，再由高压油推动液压马达驱动搅拌筒，装载量为9～12立方的则由车载辅助柴油机带动液压泵驱动液压马达。叶片是搅拌装置中的主要部件，损坏或严重磨损会导致混凝土搅拌不均匀。另外，叶片的角度如果设计不合理，还会使混凝土出现离析。

For the automatic feeding mixer with a loading capacity of 3-6 cubic meters, the vehicle 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 mixer with a loading capacity of 9-12 cubic meters, the vehicle auxiliary diesel engine drives the hydraulic pump to drive the hydraulic motor. The blade is the main component of the mixing device, and damage or serious wear will lead to uneven mixing of concrete. In addition, if the blade angle is not reasonable, the concrete will appear segregation.