Failure analysis of Sany 135 rotating without action and rotating shaking
Since the beginning of winter, in addition to the damage caused by the cold weather, excavators also seem to be "climate sensitive", and abnormal failures occur from time to time, which greatly hinders the construction efficiency
Today, we bring you the analysis of the failure of Sany 135 excavator in winter. It is pure dry goods!
Fault phenomenon:
The user reported that it was cold in winter. When Sany 135 excavator was just started, there was no turning action or shaking. It was normal after warming up
Analysis on the causes of swing shaking due to no action of excavator swing:
According to the fault phenomenon, under normal conditions, there are the following reasons for single no rotation action or rotation shake:
1. There is no pilot pressure for rotation, which causes the main valve stem of rotation not to open
2. The main rotary valve is stuck or stuck at a certain position
3. There is internal leakage in the swing motor
4. The slewing reducer is faulty and the gear is stuck
5. The rotary brake cannot be opened, and the brake release oil circuit is faulty, including the brake release solenoid valve
6. Slewing bearing failure includes ball bearing deformation, which leads to slewing bearing jamming
However, if we add the low temperature in winter, what are the other reasons?
In fact, the above failure points can hardly be avoided, but the situation of the failure points may have abnormal factors such as low temperature in winter. For example:
7. The water inside the slewing ring freezes between the slewing ring and the reducer
8. The brake cannot be opened and released due to the viscosity of hydraulic oil
Which machines are prone to failure
Some old-age machines or excavators with too high viscosity of hydraulic oil will have the seventh and eighth kinds of faults, especially in the north. It is very cold in winter. If there is rain and snow, it is easy to get rain and snow from the poorly sealed central rotary joint, the bottom of the rotary reducer, and the slewing ring grease addition port, resulting in icing of the internal gear ring of the slewing ring. This is the seventh kind of fault point
When the excavator is parked overnight and the motor car is started in the morning, the kinematic viscosity of hydraulic oil is very large, which is also the so-called low pour point When the pour point is very low, the viscosity characteristics of 32 # and 46 # hydraulic oils are: (mm) ? Indicates viscosity, the larger the value, the greater the flow resistance)
From the above table, it can be seen that the viscosity of hydraulic oil at low temperature is very high, and the flow resistance is also very large. Generally, the brake release pressure is between 1.2-2.9mp, and the oil film formed by the hydraulic oil with high viscosity will also generate very large resistance, resulting in the greater force of the brake piston. In addition, the resistance of the low-temperature hydraulic oil to its own flow is very large, so the brake piston cannot be opened or fully opened with the normal pressure of 1.2-2.9mp, Thus, the rotary motion cannot be realized or the motion is stuck and shaken
terms of settlement:
The pilot pressure and overflow pressure of slewing are detected respectively. The pilot pressure of most models is generally between 3.5mp-4.2mp, and the main overflow pressure is between 27mp-32mp, which varies according to the brand and model. If these two pressures are not abnormal, the faults of 1, 2 and 3 can be basically eliminated
For the remaining 4, 6 and 7, remove the internal components of the slewing reducer and slewing ring and inspect them with naked eyes
5 and 8 are generally difficult to judge. The inspection method is to disassemble and inspect the rotary solenoid valve, components and oil circuit of the rotary brake
summary
The failures that will occur at low temperature in winter are definitely not only rotation problems, but also other failures such as slow action and hydraulic oil pipe explosion. If you are working in winter, you can also try to replace 32 # hydraulic oil
