The mixing device of cement concrete mixer truck is similar to cement concrete mixer. It is mainly composed of mixing drum, mixing drum driving device, loading and unloading device, mixing drum supporting device and water supply system.
During operation, the engine drives the mixing drum to rotate through the power take-off drive shaft, hydraulic transmission system and gear reducer. Mixing or loading is carried out when the mixing drum is rotating forward, and unloading is performed when the mixing drum is reversed. The rotation speed and rotation direction of the mixing drum are realized by changing the swash plate angle of the hydraulic motor according to the working state of the vehicle.
1. Mixing drum structure
Most of the mixing cylinders adopt pear shaped structure, which is a double cone with variable section and asymmetric surface, which is similar to pear. A pair of unequal length truncated cones are butted from the middle diameter to the two ends. The bottom cone is short and the end face is closed. The upper cone is long, the end is open, and the center shaft is installed on the low end face. There is an annular raceway outside the upper cone. The whole mixing drum is inclined and horizontal through the central shaft and annular raceway. The self-aligning bearing fixed on the frame and a pair of supporting rollers form a three-point supporting structure, so it can rotate smoothly around its axis. The driving force of mixing drum comes from the drive of hydraulic motor to the central shaft.
Figure 13-3 mixing device of concrete mixer truck
1 - loading hopper 2 - ring raceway 3 - mixing drum 4 -; connecting flange 5 - reducer 6 - additional frame 7 - supporting roller 8 - adjusting mechanism 9 - movable discharging chute 10 - Fixed discharging chute
The internal structure of mixing drum is shown in Fig. 13-4. Two continuous ribbon spiral blades 2 are symmetrically welded along the inner wall of the mixing drum longitudinally. When the mixing drum rotates, the blades are driven to move around the axis of the mixing drum to mix or discharge concrete. In order to improve the mixing efficiency, an auxiliary mixing blade 3 is also installed in the cylinder.