When most card friends are driving the dump truck, if the hydraulic system of the vehicle fails, they often have to stop the transportation business and wait for the after-sales personnel of the manufacturer to deal with it. Moreover, sometimes when the manufacturer provides remote guidance, the card friends can’t find the location of the parts they say, which often delays time of dump truck.
If we can solve the problems in the hydraulic system of the dump truck by ourselves, or we are familiar with the installation position of accessories, will it save downtime and make more transportation?
To solve the fault problem of the hydraulic system, we must first understand its working principle: the gas taken out of the chassis air chamber is transmitted to the change-over valve through the manual control valve. At this time, the gear pump extracts the hydraulic oil through the low-pressure oil pipe, and the change-over valve pumps the hydraulic oil to the oil cylinder through the high-pressure oil pipe, The purpose of controlling the lifting and lowering of the cargo box is achieved through the lifting and lowering of the oil cylinder.
When the cargo box fails to lift or the box shakes during lifting, it shall be checked from the configuration of manual control valve, gear pump and directional valve mentioned above.
Turn on the power take-off switch in the cab, and then put the manual valve at the bottom of the left side of the driver’s seat in the lifting state (usually pull the control lever up). The container does not respond, or the container cannot be lifted to the maximum angle, so we need to see what the problem is.
After placing the manual control valve in the lifting position, directly touch the outer surface of the gear pump under the frame with your hand. Under normal working conditions, the surface temperature of the gear pump is almost the same as that of room temperature, and there is no feeling of hot hands. If the temperature is too high, the gear pump may be damaged. Find the nameplate posted on the gear pump housing and replace the gear pump of the same model.
If there is no problem with the gear pump, we should remove the air inlet pipe above the manual control valve, check whether the pressure of the air inlet pipe meets the manufacturer’s configuration requirements, then remove the air outlet pipe of the manual control valve, and then move the manual control valve back and forth to check whether there is gas flow at the air outlet above the manual control valve. If not, we only need to replace the manual control valve of the same specification.
Generally, the manufacturer will mark the air outlet and air inlet above the manual control valve at the gas pipe connection.
If there is no problem with the manual control valve, it is necessary to put the manual control valve in the lifting state, find the limit valve installed next to the oil cylinder base, and remove the two air pipes connected above. If the air pressure of both air pipes is normal, the limit valve may be stuck, and a little screw loosening agent needs to be sprayed on the valve core.
Generally speaking, one 8 × 4 heavy dump truck starts from opening the manual control valve to operate the lifting action command, and the container is lifted to the maximum angle (the hydraulic cylinder reaches the maximum stroke). In this process, the rising state of the container is very stable and there will be no shaking. If there is shaking, pay great attention to continue to let the hydraulic system work under this state, It is easy to cause safety problems such as rollover.
In this case, first stop the lifting operation, put the manual control valve in the lowering state (usually pull down the control lever), restore the container to the horizontal position, and then check whether the hydraulic oil tank is about to run out through the lookout port of the hydraulic oil tank, and check whether the gear pump pressure meets the manufacturer’s requirements. If these are normal, Then it is necessary to track whether there is air leakage, pressure folding and other phenomena on the whole installation route of the two air pipes led out from the air chamber.
Shaking occurs when the cargo box is lifted, in part because the hydraulic oil used by card friends contains a lot of impurities, and the elbow of the hydraulic oil pipe is blocked, which hinders the oil supply and can not reach the amount of hydraulic oil required for normal lifting of the cargo box.
Some card friends in Yunnan Guizhou region left a message in the background, saying that the hydraulic oil tank of a brand dump truck they bought had cracks in varying degrees. Is it because the brand of the vehicle is not good and the use of fake and shoddy products?
Through the photos sent by kayou, we can find that the cracking of the oil tank is at the connection between the change-over valve and the oil tank. In terms of the direction of the hydraulic oil pipe, the oil pipe support gap is large. Compared with the use of this brand of hydraulic oil tank in other manufacturers, there has been no oil tank skin tear.
Therefore, if you choose to buy a dump truck with a side hydraulic oil tank, you’d better install several support devices at the side protection in advance to prevent severe friction at the connection between the change-over valve and the oil tank due to excessive vibration amplitude of the oil pipe during the operation of the hydraulic system, resulting in tearing of the oil tank.
If the support device is installed in advance, it will not only save the maintenance processing time, but also save money, because the price of an ordinary hydraulic oil tank is basically about 900 yuan, while the installation of the support device only takes a few minutes, and the price is very low. It may be 100 yuan after treatment.
During the use of the dump truck, if there are problems, it is most safe and reliable to check under the guidance of the manufacturer’s technicians. This article is only for reference. The specific fault treatment method is mainly based on the scheme given by the manufacturer’s after-sales service.
Because the chassis and top loading (container production) of the dump truck are basically completed by the cooperation of two manufacturers, and the hydraulic system is handled by the top loading manufacturer. When applying for repair information, card friends can also solve the problem by calling the 400 service hotline of the top loading manufacturer in addition to calling the 400 service hotline of the chassis manufacturer. Moreover, they can directly call the phone of the top loading manufacturer without the chassis manufacturer’s reporting, It can save some time. After all, the longer the delay, the more losses will be caused.