Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Bad contact pattern gearset

Bad contact pattern gearset

RE: Bad contact pattern gearset

Is that a new crown wheel?
Is the pinion new?
Have they been running together long enough to bed-in?
Were they bedded-in in the same setup used to produce the marks in the photo?

je suis charlie

RE: Bad contact pattern gearset

Thanks for the reply,

Yes, all parts are new. It is a problem we have in the production of the gear set.
The gearset has been bedded-in according to standard procedure in a bedding in equipment.
The gearset is not assembled in a vehicle.

RE: Bad contact pattern gearset

I'm not an expert at interpreting contact patterns on (hypoid?) gear teeth. But one suggestion I have is that if you have a profile inspection chart for this particular gear, check it for a hollow condition at this location.

RE: Bad contact pattern gearset

Yeah, it almost has to be a hollow on either crown wheel or pinion doesn't it.

je suis charlie

RE: Bad contact pattern gearset

Maybe I'm seeing it wrong, but it appears to me that the picture is of the so-called "coast" side of the teeth, not the "drive" side?

RE: Bad contact pattern gearset

No, the convex flank of the ring gear teeth is normally the drive side.

You can see the coast side contact pattern on the tooth flank at the bottom of the photo. It looks biased towards the toe and way above the pitch line. I believe both drive and coast side contact patterns of a new hypoid gear set run with minimal load should be fairly similar with a slight toe bias. As load is increased during service and the gears bed in, the contact pattern should spread out and move towards the heel.

One issue that this gear seems to have is that is was manufactured with a lower level of precision. Obviously it was not finish ground, since there are machining marks present on all surfaces, including flanks, roots and tips. I assume this gear was case hardened, and if the gear is not going to be finish ground after hardening, you might consider adding some correction to the machined tooth profile to compensate for heat treat distortions.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close