How to deal with excavator arm stuck?

How to deal with excavator arm stuck? Only the tacit cooperation between the movements of the excavator’s large and small arms can ensure that the machine’s operation is not affected. It can also be said to be the most basic guarantee for the efficiency and completion time of the project. Therefore, 99% of the machine operators are worried about problems with the movements of the large and small arms. But worry is worry. If the fault really occurs, don’t rush to find a way to repair it. Today we will use a case to see how an owner solved the forearm retraction jam problem. I hope it can help Bring your references!

Fault phenomenon
According to the owner’s description, his excavator has had less than 5,000 construction hours since it was brought back as a new machine. He never borrows other people’s hands to drive it, not to mention the maintenance, which is given with twelve minutes of care. Recently, during the construction process, there was an obvious pause when the machine’s forearm was retracted to an angle perpendicular to the ground. This abnormal phenomenon attracted great attention from the machine owner. In order not to delay more construction time, he immediately contacted the maintenance master to carry out the work. solve.

Failure analysis
The maintenance technician arrived at the scene and based on the fault phenomenon and reviewed the relevant introduction to the hydraulic working principle of the machine, he initially identified the fault point and analyzed the reasons as follows:

1. This machine is designed and adds a regeneration function in the forearm recovery oil circuit. A brief introduction to the benefit of the regeneration function is to prevent the forearm cylinder from extending too fast under the action of the forearm’s own weight when the forearm is recovered, thus causing the The formation of cavities in the oil cylinder will cause adverse effects. On the other hand, it is also necessary to prevent the forearm from stalling and increase the recovery speed of the forearm.
2. The key point is that this function is jointly realized through the one-way valve and the forearm regeneration valve in the ARM1 valve core. With this visible fault point, we must also focus on these two parts.
3. Returning to the working principle of the machine, when the machine owner selects the excavation construction mode, the regeneration valve spool is in the throttling position to limit the oil return to the rod cavity of the oil cylinder. When the oil pressure in the rod cavity is higher than the oil pressure in the rodless cavity, the one-way valve in the ARM1 valve core opens, allowing the return oil from the rod cavity to return to the rodless cavity to achieve the regeneration function.
4. So through the above introduction, everyone will easily understand that if the regeneration valve spool cannot be in the throttling position or the one-way valve in the ARM1 spool cannot be opened smoothly, the regeneration function in the forearm circuit cannot be realized. This causes the forearm to pause in the vertical position.

Maintenance process
After analyzing the above working principles, the engineer first focused on checking the regeneration valve spool and pilot oil circuit. No abnormal faults were found. The cause can be eliminated immediately. When the maintenance technician inspected the one-way valve in the ARM1 valve core, he found that the orifice at the front end of the one-way valve was blocked by foreign matter, which prevented the one-way valve from opening, which ultimately led to this failure.

Approach
Because the throttle hole was only blocked by foreign matter and caused the failure, and there was no other abnormal wear and tear, it was only necessary to thoroughly clean the throttle hole before re-testing. It was found that the pause phenomenon of the recovery arm did not reappear, indicating that the fault had been resolved.

Summarize
The machine will not lie, nor will it play tricks on the owners. Once you find any abnormal faults in your machine, don’t take chances. Repair it immediately when the fault is minor. Whether it is maintenance costs or time-consuming, it will be greatly reduced!

If you need to purchase a XCMG excavator, you can contact us at any time. In addition, if you want to buy excavator spare parts or second-hand excavators, CCMIE is also your best choice.