×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Jobs

Crossed Axis Helical Surface Compressive Stress

Crossed Axis Helical Surface Compressive Stress

Crossed Axis Helical Surface Compressive Stress

(OP)
I'm designing a hand operated lifting mechanism using a crossed axis helical gearset with a 40:1 ratio.  As this gives a point contact, the compressive stress on the tooth surface is in the neighborhood of 200 ksi, and I'm having difficulty reducing this.  Some things I've tried:
 
(a) increased the O.D. of the driven gear to the maximum allowed, 4.5 inches, by increasing diametral pitch.
(b) made sure the contact ratio is over 2.

Typically we've used a steel (not heat treated) worm with a gray iron gear, but I'm afraid this will wear very prematurely.  The gearbox is open with the possibility of running dry.

Is there any way to get this stress down, or will the gear wear to a point and then stop? Does this merit a change to a true worm gear?  Any material suggestions are appreciated as well.

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!


Resources