Has anyone ever made a reduction gearbox?
Close
Login to Your Account
Page 1 of 3 123 LastLast
Results 1 to 20 of 49
  1. #1
    Join Date
    Mar 2005
    Location
    near Rockhampton, Queensland, Australia
    Posts
    5,538
    Post Thanks / Like
    Likes (Given)
    441
    Likes (Received)
    2070

    Default Has anyone ever made a reduction gearbox?

    I need to make an inline reduction gearbox of close to 1.5:1 ratio to slow the output of a small 27hp diesel motor to 1500rpm to run a generator. No more then 50ft lb's torque on the input.

    Are these incredibly complex things to build or just relatively basic so long as you have good common sense.

  2. #2
    Join Date
    Mar 2012
    Location
    Geilenkirchen, Germany
    Posts
    2,399
    Post Thanks / Like
    Likes (Given)
    1446
    Likes (Received)
    1222

    Default

    Quote Originally Posted by RC99 View Post
    I need to make an inline reduction gearbox of close to 1.5:1 ratio to slow the output of a small 27hp diesel motor to 1500rpm to run a generator. No more then 50ft lb's torque on the input.

    Are these incredibly complex things to build or just relatively basic so long as you have good common sense.
    I don't think it would be overly difficult, but I can't believe it makes any economic sense or is in the least bit practical. It appears you have a 4 pole alternator and want to make 50 Hz power. You are far better off selling your 4 pole and buying a 2 pole alternator, then get the correct engine governor and be done with the problem.

  3. #3
    Join Date
    Jan 2005
    Location
    The Netherlands
    Posts
    5,821
    Post Thanks / Like
    Likes (Given)
    276
    Likes (Received)
    1496

    Default

    Why not use a V-belt transmission ?

    Peter

  4. Likes Kjelle liked this post
  5. #4
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    7,751
    Post Thanks / Like
    Likes (Given)
    1811
    Likes (Received)
    5453

    Default

    I've seen simple toothed-belt with taper roller bearings supported shafts used for stepping down engine output, and that unit lasted for years. But I'm surprised that your engine has a base RPM of 7500, that's awfully high for a diesel.

  6. #5
    Join Date
    May 2012
    Location
    Pittsford, NY
    Posts
    1,038
    Post Thanks / Like
    Likes (Given)
    717
    Likes (Received)
    668

    Default

    Old guy I knew made a 2:1 out of the sprockets and chain from an car engine. I don't know if that is too far off for you. A lot less critical than gears. Autozone sells a silent chain set for $22.99. https://www.autozone.com/internal-en...52881_690132_0

    A little research may find mixed automotive parts that would get you closer to 1.5 to 1.

  7. #6
    Join Date
    May 2017
    Country
    FINLAND
    Posts
    1,777
    Post Thanks / Like
    Likes (Given)
    496
    Likes (Received)
    812

    Default

    Quote Originally Posted by Milland View Post
    I've seen simple toothed-belt with taper roller bearings supported shafts used for stepping down engine output, and that unit lasted for years. But I'm surprised that your engine has a base RPM of 7500, that's awfully high for a diesel.
    1½ to 1

    I'd also take a hard look on belt drive possibility, lot more forgiving to build than inline gearbox.

  8. Likes Kjelle liked this post
  9. #7
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    7,751
    Post Thanks / Like
    Likes (Given)
    1811
    Likes (Received)
    5453

    Default

    Quote Originally Posted by MattiJ View Post
    1½ to 1

    I'd also take a hard look on belt drive possibility, lot more forgiving to build than inline gearbox.
    Too early in the morning for me, I misread it as 5:1. D'Oh!

  10. #8
    Join Date
    May 2017
    Country
    UNITED STATES
    State/Province
    Massachusetts
    Posts
    318
    Post Thanks / Like
    Likes (Given)
    325
    Likes (Received)
    161

    Default

    I'm going to second the belt drive simplicity. There are pto driven chippers that achieve a similar result with a jack-shaft pulley arrangement (3 v belts to handle the load).

  11. #9
    Join Date
    Sep 2010
    Location
    Oklahoma City, OK
    Posts
    4,472
    Post Thanks / Like
    Likes (Given)
    773
    Likes (Received)
    1849

    Default

    Belt drive could even still be inline, just require a mid-shaft.

  12. #10
    Join Date
    Oct 2005
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    15,612
    Post Thanks / Like

    Default

    Last edited by digger doug; 03-13-2019 at 06:56 AM.

  13. #11
    Join Date
    Apr 2010
    Country
    UNITED STATES
    State/Province
    Wisconsin
    Posts
    6,106
    Post Thanks / Like
    Likes (Given)
    4195
    Likes (Received)
    3758

    Default

    Make them all the time. Planetaries, even. For your needs, you'd do well to heed the advice given and look at pulleys, belts, and jack shafts. Easy-peasy.


  14. Likes RC99, Demon73, 10 fingers, gmoushon, Kjelle and 2 others liked this post
  15. #12
    Join Date
    May 2017
    Country
    UNITED STATES
    State/Province
    Massachusetts
    Posts
    318
    Post Thanks / Like
    Likes (Given)
    325
    Likes (Received)
    161

    Default

    One cautionary note (not to dissuade from going the pulley route) but just to consider.

    A gearbox will usually pretty much lock in alignment. A simple and cheap pulley/jack-shaft arrangement is often based on pillow-blocks. Those arrangements can be sensitive to alignment issues. I snapped a 1 1/2" chipper jack shaft after carelessly keeping the chipper engaged while I lifted the implement. Resulted in a minor misalignment of the input shaft which wobbled the jackshaft without my realizing it. The fatigue from running the misaligned 1 1/2" shaft even for just a minute or two snapped it like a toothpick.

    Not saying that misalignment couldn't damage a gearbox...and not saying it wasn't 100% user error on my part...just observing pillow blocks don't take much torque to misalign.

  16. #13
    Join Date
    Mar 2009
    Location
    Brunswick Oh USA
    Posts
    4,535
    Post Thanks / Like
    Likes (Given)
    5069
    Likes (Received)
    2704

    Default

    I agree with Zanhrad. Here;s a simple reduction I made for my snow blower. Worked fine, just took forever. Poke the pic for more.


  17. Likes RC99, Dualkit, atomarc, sandiapaul, Demon73 liked this post
  18. #14
    Join Date
    Jul 2006
    Location
    Australia (Hobart)
    Posts
    3,580
    Post Thanks / Like
    Likes (Given)
    569
    Likes (Received)
    2715

    Default

    Quote Originally Posted by RC99 View Post
    I need to make an inline reduction gearbox of close to 1.5:1 ratio to slow the output of a small 27hp diesel motor to 1500rpm to run a generator. No more then 50ft lb's torque on the input.

    Are these incredibly complex things to build or just relatively basic so long as you have good common sense.
    I've got a 2 pole 7.5kW generator head I'd swap for a 4 pole..... freight/distance probably a deal killer though. Or I could do you a good deal on a Lister 1500/1800 rpm diesel. Kind of planning the same thing as you but the reverse - I need to get the generator head up to 3000 rpm.

    Email me if you're interested. We might be able to work something out on freight as I'm driving north in another month or 2.

    PDW

  19. #15
    Join Date
    Jul 2004
    Location
    Houston, TX USA
    Posts
    30,053
    Post Thanks / Like

    Default

    Here are two "coaxial" or inline reducers I used on this head stock over 30 years back. So you can certainly BUY such things
    Attached Thumbnails Attached Thumbnails spiral-mill-12.jpg  

  20. #16
    Join Date
    Dec 2004
    Location
    uk
    Posts
    14,057
    Post Thanks / Like
    Likes (Given)
    4552
    Likes (Received)
    6704

    Default

    Honestly the hardest bit is making it oil tight, the gears are best bought of the shelf the rest is a couple of bearing fits, Holding shaft centers to typical good machining tolerances works just fine.

    Belt drive and out of line is far easier, but most small alternators are not setup for belt drive side loads.

  21. #17
    Join Date
    Apr 2005
    Location
    Beaverdam, Virginia
    Posts
    7,452
    Post Thanks / Like
    Likes (Given)
    704
    Likes (Received)
    3518

    Default

    Quote Originally Posted by adama View Post
    Belt drive and out of line is far easier, but most small alternators are not setup for belt drive side loads.
    You would be surprised at some of the loads we put on beefed up automobile alternators and never smoked any bearings. We are talking spinning 200+ amp alternators at over 8,000 RPM with nothing but the stock cheap Chinese bearings in them that at the time in volume cost a measly $1.50 each. Due to the excessive drag created the belt had to be run on the tight side.

  22. #18
    Join Date
    Mar 2005
    Location
    near Rockhampton, Queensland, Australia
    Posts
    5,538
    Post Thanks / Like
    Likes (Given)
    441
    Likes (Received)
    2070

    Default

    Thanks, I did consider belt drive but wanted to get away from that. I could buy a 2 pole but a suitable one is $2000. Compared to the current $0 in the current one, which if sold would only be worth scrap as who would believe you it worked. It is a good alternator 15kVa continuous @ 240V 0.8 pa.

    Still keeping my options open.

  23. #19
    Join Date
    Jul 2006
    Location
    Australia (Hobart)
    Posts
    3,580
    Post Thanks / Like
    Likes (Given)
    569
    Likes (Received)
    2715

    Default

    Quote Originally Posted by RC99 View Post
    Thanks, I did consider belt drive but wanted to get away from that. I could buy a 2 pole but a suitable one is $2000. Compared to the current $0 in the current one, which if sold would only be worth scrap as who would believe you it worked. It is a good alternator 15kVa continuous @ 240V 0.8 pa.

    Still keeping my options open.
    My plan is/was to use belts but I've got an alternator that has bearings front & back not using the crankshaft to provide the front bearing. Plus I have 2 spare air cooled diesel engines.

    An inline gearbox would be a lot neater though.

    PDW

  24. #20
    Join Date
    Dec 2004
    Location
    uk
    Posts
    14,057
    Post Thanks / Like
    Likes (Given)
    4552
    Likes (Received)
    6704

    Default

    Quote Originally Posted by Dualkit View Post
    You would be surprised at some of the loads we put on beefed up automobile alternators and never smoked any bearings. We are talking spinning 200+ amp alternators at over 8,000 RPM with nothing but the stock cheap Chinese bearings in them that at the time in volume cost a measly $1.50 each. Due to the excessive drag created the belt had to be run on the tight side.
    Yes car alternators have bearings both ends, lots of generator mounted "power aka mains voltage" alternators only have a bearing the far end! its how they effectively get around the whole shaft alignment issue. Equally they tend to bolt straight onto the fly wheel face, so lots don't even really have a shaft more some kinda coupling flange.

    200 amps at 12v is only what 2.4Kw? Aka 3hp ish? Were looking at 15kw over 6 times more transmitted power here and far more than a single V belt will transmit.


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •