×
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

Current status on recess action gears?

Current status on recess action gears?

Current status on recess action gears?

(OP)
Hi,
As I understand it there is an old rule about full recess action gears. If the pinion has all addendum and it is driving the gear it will run smoothly but if the gear then drives the pinion it will be much problems. This comes mostly from old books (1960 and earlier) but I haven't seen it mentioned in newer literature and don't find much in scientific articles.
I will not have full recess gears but maybe 75-90% addendum to dedendum on pinion and the gear maybe drives the pinion 20-30% of the time (hypoid axle gear).

I read this website:
http://www.csparks.com/watchmaking/CycloidalGears/RichardThoen.xhtml
where Thoen says that for involute gears this is from an old time when surface roughness and pitch errors was much bigger.

With modern machines and manufacturing, is this still an issue or can I stop worrying about the gear driving the pinion occasionally?

RE: Current status on recess action gears?

A gearset that has mostly recess action for speed reduction will have mostly approach action for speed increasing.  This will have significant effects on specific sliding and contact point temperature.  Get some good gear analysis software and check your gearset for:

    power rating for pitting resistance (wear)
    power rating for tooth bending strength
    contact point flash temperature

If the contact point flash temperature is higher than recommended for your lubricant, the likelihood of scoring increases.

RE: Current status on recess action gears?

The issue of all recess gears is extensively covered in the book On the Geometry of External Spur Gears by T.W. Khiralls Chapter 7 page 256 to 270. Khiralla was a great advocate of these types of gears and brings examples how he solved failure of gears in machines by replacing them with all recess gears (without changing the center distance).

Quoting Khiralla "The power flow must always be from the all addendum driver to the all dedendum follower. The all dedendum gear must never be used as a driver, because this results in an all approach action gear system which will be very noisy, have a rough tooth action and be very inefficient".

Added to Philrock post, for a gear system that is used both as a speed decreasing system and speed increasing system, the gears should be designed such that the specific sliding for both types of uses is balanced and minimized.

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