Pinion Gear Contact Surface

[NJAus1]

Hi All,

I have a pinion gear (drive gear) and a ring gear (driven gear). I have attached a photo and marked up the contact pattern on the tooth.

Does the contact pattern appear correct? Should the contact area extend up to the tip?

Thanks

 

[mfgenggear]

NJAus

what's the story , did it fail prematurely? that pitting doesn't look good.
pattern looks proper.

 

[tbuelna]

I agree with mfgenggear's comment. Pitting at low point of contact on the pinion tooth flank is an obvious problem. Adding some tip relief to the ring gear teeth might help.

 

[geesamand]

The pattern can look like that if the pinion teeth are intentionally longer than the gear teeth.

The extents of the contact pattern will vary with the degree of loading. If you operate the drive with large service factor, the contact pattern will be smaller.

 

[mfgenggear]

Just to add,
Two possibilities
#1) end of life for the pinion.
Surface fatigue failed causing pitting.
#2) surface duribility miscalculated.
The hardness of the pinion tooth. Flanks not hard enough.