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"Security is no small matter in front of" Impact cranes special gear failure What are the reasons?
1, tooth wear
For open gear or gear lubricants containing closed dirty, since the relative sliding engagement between the tooth surface to make some hard abrasive particles into the friction surface, so that the tooth profile changes, increased backlash, that thinning cause excessive gear tooth broken. Under normal circumstances, only when mixed with abrasive grains, will cause tooth abrasion in the lubricant in operation.
2, the tooth surface gluing
For cranes special gear, because a larger friction between the tooth surface, relatively large velocity, resulting in the engagement zone temperature is too high, poor lubrication conditions once the oil film between the tooth surface will disappear, so that the metal surface of the two teeth directly exposure, which occurred bonded to each other. When two tooth surface relative motion continues, the harder the tooth surface portion of the material along the sliding direction of the soft tooth surface tear formed grooves.
3, fatigue pitting
When two intermeshing tooth contacts, action and reaction between the tooth surfaces make contact stress generated on both the work surface, since the position of the engagement point is changed, and the gear to do periodic motion, the contact stress is press pulsation cycle change. Tooth surface for a long time in this alternating contact stress under the action of the marks of the tooth surface appear small cracks, over time, the crack in the surface gradually scale, crack formation after ring, the wheel tooth surface produce small areas of peeling and the formation of some fatigue shallow pit.
4, broken teeth
Load-bearing running gear works as a cantilever, the roots are cyclically stressed pulse exceeds the fatigue limit gear material may crack at the root, and gradually expand, while the remaining portion can not afford to drive load occurs teeth broken. Gear as a result of severe shock, partial load and uneven material may also cause broken teeth.
5, teeth plastically deformable
Impact load or reload, the tooth surface is easy to produce localized plastic deformation, so that the involute tooth profile surface deformed.
For more information: Precision gear shaft spline