The concrete mixer truck is composed of an automobile chassis and a special device for concrete mixing and transportation. The chassis of concrete mixer trucks produced in China mostly adopts class II general chassis provided by vehicle manufacturers. Its special mechanism mainly includes power takeoff, front and rear supports of mixing drum, reducer, hydraulic system, mixing drum, operating mechanism, cleaning system, etc. The working principle is that the power of the automobile chassis is taken out through the power take-off device, and the variable pump of the hydraulic system is driven to convert the mechanical energy into hydraulic energy and transmit it to the quantitative motor. The motor then drives the reducer, and the reducer drives the mixing device to mix the concrete.
Power take-off device
The 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 and drive the mixing drum through the hydraulic system. 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 work.
The engine power taken out by the power takeoff is converted into hydraulic energy (displacement and pressure), and then output into mechanical energy (speed and torque) by the motor to provide power for the rotation of the mixing drum.
The speed output by the motor in the hydraulic system is decelerated and transmitted to the mixing drum.
(1) Control the rotation direction of the mixing drum to make it rotate forward during feeding and transportation and reverse during discharging.
(2) Control the rotating speed of the mixing drum.
The mixing device is mainly composed of mixing drum and its auxiliary supporting parts. The mixing drum is the loading container of concrete. 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.
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.
The main function of the cleaning system is to clean the mixing drum, and sometimes it is also used for dry material mixing drum during transportation. The cleaning system also cools the hydraulic system.
Totally enclosed device
The fully enclosed device adopts rotary sealing technology to seal the inlet and outlet of the mixer truck, and solves a series of problems such as water evaporation, mortar stratification, concrete scattering and driving safety of the traditional mixer truck.
As a transport vehicle, the maintenance and repair of concrete mixer truck must comply with the provisions of order No. 13 of the Ministry of communications in 1990 and implement the maintenance and repair system of "regular inspection, compulsory maintenance and repair as appropriate". On this premise, combined with the actual situation of concrete mixer truck, do a good job in maintenance and repair. In terms of daily maintenance, in addition to routine maintenance of vehicle engine, chassis and other parts, the concrete mixer truck must also do the following maintenance work.