Continuous bearing wear in the big end of the reciprocating compressor rod～
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For the 6m50 compressor, at the reverse load end (Stage 1), the first connecting rod big-end bearing kept burning out; 3 sets of big-end bearings had to be replaced within three days. During no-load testing, the bearings also burn out. In previous cases of tile burning, the issue was either alloy flaking or circumferential wear; however, the phenomenon observed this time is quite abnormal (as shown in the figure) – the alloy has been extruded and deformed along the axial direction. I hope experts can provide some guidance
What is the data measurement status for each section? ?
It should be lubricated with thin oil; is the oil hole blocked? Send a few more sheets with more content. Such movies are too monotonous.
Was this large tile ground before installation? It's best to have photos. Also, pay special attention to checking the oil circuit, the clearance of the bearing shells, and the surface finish of the shaft.
Did the shaft bearing deflect during disassembly? It is very likely that the clearance between the bearing bush and the bearing is too small; the bearing bush rotates in close contact with the bearing, and this rotation blocks the lubrication holes, resulting in the bearing bush burning due to a lack of lubrication.
Items to be checked: 1> Check the center of the groove on the shaft relative to that of the compressor (based on the wear marks on the bearing shells, it is most likely that the shaft is not in the correct position). 2> Examine the ellipticity and surface finish of the areas where the shaft diameter comes into contact with the bearing shells. 3> Check the straightness of the shaft diameter. 4> Inspect the contact between the back of the bearing shell and the bearing housing, as well as the degree of tightness. 5> Check whether there is any separation between the alloy layer of the bearing shell and its core structure, i.e., what you refer to as “peeling”. 6> Examine the condition of the fit between the bearing shell and the shaft diameter (this can be determined in conjunction with point 1). 7> Check the lateral clearance between the bearing shell and the shaft diameter (this can also be determined together with point 1). 8> Verify whether there are any blockages in the oil circulation system within the bearing housing and bearing shells. 9> Check whether the clearance between the bearing shell and the shaft diameter is too small. 10> Check whether the tension applied to the bearing shell is too high. Based on the current data and images, these are all necessary checks; if there are any omissions or errors, please feel free to correct them. This information is provided for reference only
Items to be checked: 1> Check the center of the groove on the shaft relative to that of the compressor (based on the wear marks on the bearing shells, it is most likely that the shaft is not in the correct position). 2> Examine the ellipticity and surface finish of the areas where the shaft diameter comes into contact with the bearing shells. 3> Check the straightness of the shaft diameter. 4> Inspect the contact between the back of the bearing shell and the bearing housing, as well as the degree of tightness. 5> Check whether there is any separation between the alloy layer of the bearing shell and its core structure, i.e., what you refer to as “peeling”. 6> Examine the condition of the fit between the bearing shell and the shaft diameter (this can be determined in conjunction with point 1). 7> Check the lateral clearance between the bearing shell and the shaft diameter (this can also be determined together with point 1). 8> Verify whether there are any blockages in the oil circulation system within the bearing housing and bearing shells. 9> Check whether the clearance between the bearing shell and the shaft diameter is too small. 10> Check whether the tension applied to the bearing shell is too high. Based on the current data and images, these are all necessary checks; if there are any omissions or errors, please feel free to correct them. This information is provided for reference only
Check the ellipticity and conicity of the crankshaft; it’s very likely that they are out of spec, which leads to excessive local pressure on the bearing shells.
The excessive clamping force between the large-head tile and the crankshaft at a certain extreme position is the cause of this issue; it is recommended to recheck the dimensional specifications and clearances of the crank structure to determine if there is any deformation, that is, to inspect the center of the depression as mentioned above.