The whole machine is composed of transmission device, working mechanism, body and auxiliary devices.
1. Transmission device The transmission device consists of an electric motor, a hydraulic coupling, a reducer, and a column.
a.retarder. The reducer adopts a three-stage gear transmission, with the first stage being a spiral bevel gear transmission, and the second and third stages being cylindrical gear transmission. The upper box is equipped with a ventilation hood for balancing the air inside and outside the box. Each part where the gears mesh is equipped with an observation window, which facilitates the observation of the meshing and lubrication of the gears. The bottom of the reducer is equipped with a magnetic oil plug to capture iron filings in the lubricating oil, reduce wear on gears and bearings, and improve their service life. The gears and bearings at the bottom of the reducer are immersed in oil for oil bath lubrication, while the remaining gears and bearings are lubricated by the lubrication system.
b、 Hydraulic coupling The hydraulic coupler is used to connect the motor shaft and the high-speed shaft of the reducer, It is mainly composed of pump impeller and blades. The cavity between the pump impeller and the impeller is filled with working oil. During operation, the electric motor drives the pump wheel through the hub, which provides kinetic energy to the working oil. This kinetic energy acts on the impeller, causing it to rotate and drive the high-speed shaft of the reducer. The use of hydraulic couplings has the following advantages:
1) The starting current is small, and when the motor starts, the energy given to the working oil by the pump impeller gradually increases, so the speed of the impeller also gradually increases.
2) Has overload protection capability. If for some reason the load of the sand mixing mechanism increases significantly in a short period of time, there will be a speed difference between the impeller and the pump impeller, and the speed of the sand mixing mechanism will decrease. After the excessive load disappears, the sand mixing mechanism returns to normal working speed. Once there is a long-term overload, the speed difference between the impeller and pump impeller also increases, and the temperature of the working
oil rises due to friction. When the temperature reaches the allowable value, the melting alloy in the protective plug melts, and the oil flows out from the hole of the protective plug. The sand mixing mechanism stops working (at this time, the motor is idling), which can prevent the motor from burning out or the machine from being damaged. The hydraulic coupling selected for this machine is YOX380 type, with an oil injection volume of 7.2-7.5 liters. When working, the prescribed amount of working oil should be injected, and hydraulic oil, turbine oil, and motor oil can be selected as working oil. When installing the hydraulic coupling, the coaxiality error between the motor and the reducer should be less than 0.3mm. After the installation of the machine in the user's factory, the motor must be readjusted before commissioning. The smaller the coaxiality error, the better to ensure the normal operation of the machine.
c、 Column The column, also a part of the transmission system, is directly fixed on the chassis, and the large gear at the lower end meshes with the last gear in the reducer, forming the third stage transmission of the reduction system. The spindle drives and supports all the working mechanisms of the sand mixer, and is one of the key components. The bearing at the upper end of the spindle is lubricated with thin oil by the oil pump. During operation, the sealing cover rotates together with the crosshead. To prevent dust from entering the interior of the column sleeve, a labyrinth cover and two felt oil seals are added between the column sleeve and the cover, and butter is injected as packing at the labyrinth.
