fag bearing Technical conditions for repairing automobile engine crankshaft
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This standard is applicable to the repair of crankshaft of reciprocating plug automobile engine. The repaired crankshaft shall meet the requirements of this standard.fag bearing
1 technical requirements
1.1 flaw detection shall be conducted for the crankshaft before repair, and there shall be no cracks. However, when there are short and shallow cracks with a length of no more than 5mm around the oil hole on the journal or longitudinal cracks that do not extend to the fillet of the journal and the oil hole (the length of the journal is less than or equal to 40mm, the length of the crack is no more than 10mm; the length of the journal is greater than 40mm, the length of the crack is no more than 15mm), it is still allowed to repair.
1.2 after the Journal of crankshaft sliding bearing is worn, it shall be repaired according to the graded repair dimensions of crankshaft in Table 1. When the wear of the combined crankshaft rolling bearing journal exceeds the limit and the sliding bearing journal exceeds its allowable service limit size, it is allowed to carry out compensation repair and restore to the original design size.
Note: the original design refers to the technical documents approved by the manufacturer and according to the specified procedures (the same below).fag bearing
① The repair dimensions at all levels still use the limit deviation of the original design dimensions.fag bearingf.a.g. bearings catalogue pdf
② Grade 9 and beyond are not commonly used size grades.fag bearing
③ Crankshafts with special grading provisions shall be implemented according to their original design.fag bearing
1.3 when compensating and repairing the journal, metal wire spraying, electric vibration surfacing, iron plating, chromium plating and other methods can be used. After the wear of other parts exceeds the limit, according to the situation, in addition to the above methods, manual arc welding and other methods can also be used for restorative repair. The compensation and repair layer shall be uniform and appropriate, and the mechanical properties shall meet the use requirements. See Appendix A (Reference).
1.4 after the crankshaft is polished, the journal with the same name must be of the same repair size.
1.5 after the end faces of crankshaft main journal and connecting rod journal are worn beyond the limit, they shall be repaired to the journal width specified in the original design.
1.6 after the crankshaft is repaired, when the common axis of the main journals at both ends is taken as the benchmark:
a. The radial circular runout tolerance of each main journal in the middle is 0.05mm.
b. The parallelism tolerance between the axis of each connecting rod journal and the axis of the main journal: the integral crankshaft is Φ 0.0lmm, the combined crankshaft is Φ 0.03mm。
c. The end face circular runout tolerance of the mating end face with thrust journal and timing gear is 0.05mm.
d. The radial circular runout tolerance of flywheel flange is 0.04mm; The end face circular runout tolerance of the outer end face is 0.06mm.
e. The radial circular runout tolerance of the Journal of the belt pulley is 0.05mm.
f. The radial circular runout tolerance of the Journal of the timing gear is 0.03mm.
g. The radial circular runout tolerance of the first bearing hole of the transmission is 0.06mm.
1.7 the cylindricity tolerance of each main journal and connecting rod journal is 0.005mm.
h. The radial circular runout tolerance of oil seal journal, which adopts oil return groove to prevent leakage, is 0 L0mm, 0.05mm for leakage proof with oil seal ring.
1.8 the turning radius of connecting rod journal shall meet the basic dimensions specified in the original design. The limit deviation of integral crankshaft is ± 0.15mm, but the difference of each turning radius of the same crankshaft shall not exceed 0.20mm. The limit deviation of combined crankshaft shall meet the original design requirements.
1.9 based on the central plane of the keyway of the timing gear, the distribution angle deviation of the connecting rod journal is ± 30 ˊ。
1.10 the thread damage of starting nut hole shall not be more than 2 teeth.
1.11 the surface finish of main journal and connecting rod journal shall not be lower than V8, and the surface finish of fillet shall not be lower than ▽ 7.
1.12 the fillet radii at both ends of the main journal and connecting rod journal shall comply with the original design regulations. However, for the crankshaft repaired by metal wire spraying and electroplating, the fillet radius after repair is allowed to be appropriately reduced.
1.13 the combined crankshaft must be assembled in situ. After assembly, the coaxiality tolerance of each rolling bearing journal shall comply with the original design regulations.
1.14 the crankshaft oil passage shall be clean and unblocked. The oil hole shall be chamfered.
1.15 the repaired crankshaft shall be free of welding slag, burr, metal splash and other sundries, and the machined surface shall be free of visible nicks, black spots, bumps, depressions, hair marks, holes and other defects. However, the crankshaft surface repaired by electric vibration surfacing is allowed to have fine moire.
1.16 the crankshaft shall be subject to balance test, and its unbalance shall comply with the original design regulations.
1.17 other technical requirements not specified in this standard shall comply with the original design provisions.