×
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

RECUMBENT BICYCLE TRANSMISSION

RECUMBENT BICYCLE TRANSMISSION

RECUMBENT BICYCLE TRANSMISSION

(OP)
looking for a cure to what ails me...... I am designing a drivetrain for a front wheel drive, front wheel steering, recumbent HPV. I am currently trying to set it up like the cal berkley transmission which uses a jackshaft, two chains, and four gears. The main gear is the bike cranks then directly behind the main is the secondary gear which is coupled to a bigger gear. The second chain runs from the bigger gear along the pitch of the fork to the 16t sprocket which is attached to the internally geared hub. pics at http://calhpv.berkley.edu/pics/frontdrivetrain.jpg
THE PROBLEM THAT I HAVE IS THAT THE WESTERN HPV'S ARE MEANT TO GO FAST AND STRAIGHT. WHEREAS THE ONE WE ARE DESIGNING IS GOING TO HAVE TO TAKE TURNS AS WELL. SO HOW DO I REDUCE THE CHAIN FRICTION THAT WILL BE CAUSED WHEN STEERING AND KEEP THE CHAIN FROM POPPING OF THE HUB.
THANKS

RE: RECUMBENT BICYCLE TRANSMISSION

First chain from crank gear to secondary gear, then universal coupling on shaft supported by frame to third gear on fork, second chain to wheel sprocket.

RE: RECUMBENT BICYCLE TRANSMISSION

You will lose HP going through the secondary shaft and more through the universal joint. My recommendation is to direct drive the rear wheel(s). I drove the front wheel in a great moonbuggy competition however because the machine was a 4-wheeled vehicle with A-arm suspension with steering. With A-arm suspension you must use two universal joints and keep your pivot points of the A-arms and the driveshaft at the same plane. I also had the steering pivot points in alignment with the outboard universal. The buggy was 2-wheel drive the front left and the rear right drive wheels.  

My moonbugy took second place and the following is a link to a photo of it in action. It was not my moonbuggy but my team's but I designed the frame, suspension, and drivetrain. By the way, I was a non-traditional student and was asked several times if I was a professor which I quickly corrected by saying I was a student.

http://www.nasa.gov/centers/marshall/multimedia/photos/2005/photos05-045.html

 

RE: RECUMBENT BICYCLE TRANSMISSION

jw,
I agree with Bill about using the driven rear wheel.
While neither pro nor professor, I have build a couple hp trikes and found that the KISS principle holds very true.
My winter project this year is to move to a fully drive-shaft driven vehicle with a transmission.  
Recumbents are meant to be laid back!
Griffy

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