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Pgsaw worm gear motor backlash

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by Zed, Nov 28, 2017.

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  1. Zed

    Zed VR Simming w/Reverb Gold Contributor

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    My Motion Simulator:
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    Has anyone had issues with the backlash in the pgsaw worm gear motors and fixed it?

    I know some go with a bit out of balance condition to help but I’m looking for something that actually takes out the travel.

    Is it just needing another thrust washer or so, or is it slop in the gears? Are there any aftermarket gear sets for them that minimize backlash?

    Thanks in advance for any leads...
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    Zed, Nov 28, 2017
    #1
  2. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
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    All worm gearboxes are going to have some backlash, linear actuators are an alternate and are more efficient.

    How much play do yours have?
    • Informative Informative x 1
    noorbeast, Nov 28, 2017
    #2
  3. Zed

    Zed VR Simming w/Reverb Gold Contributor

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    My Motion Simulator:
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    It’s not much but I do get that clicking and can feel it in the frame just a little. It would be a production to switch for linear actuators.

    I can take the motors off, wiggle things, and see if the worm shaft has endplay to maybe see if they just need some more washers in there. I can’t help true backlash in the gears but if it’s the worm moving back and forth, I probably can reduce that some.

    It’s just that quest for smooth, quiet motion. :)
    • Agree Agree x 1
    Zed, Nov 28, 2017
    #3
  4. Brett Horton

    Brett Horton Active Member

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    My Motion Simulator:
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    Keep us posted, as I have some in mine as well and would like to reduce.
    Brett Horton, Nov 28, 2017
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  5. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
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    This is about average wormdrive backlash and the greater the lever CTC the more noticeable it will be:

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    noorbeast, Nov 28, 2017
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  6. PiaMan

    PiaMan Active Member

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    Ya drives me crazy the clacking. But more importantly the lost fidelity compared to my SCN rig. Would love find a solution
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    PiaMan, Nov 28, 2017
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  7. Brett Horton

    Brett Horton Active Member

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    My Motion Simulator:
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    This is exactly why I asked for a "Better" motor replacement a few months ago for the PGSaw motors we currently run.
    Gearbox and motor that is. Mainly just higher quality.
    • Agree Agree x 3
    Brett Horton, Nov 28, 2017
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  8. PiaMan

    PiaMan Active Member

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    My Motion Simulator:
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    My backlash is about the same as in that video. The worm gear setup is great for power and showing off as it will throw me or my guest out of my seat if cranked up. The scn setup however provides much more immersion due to the fine detail that is reproduced. I would equate the fidelity difference as the difference between an osw wheel and a thrustmaster t300 set to similar strength. Both have forcefeedback but the osw really tells you whats going on.
    • Like Like x 2
    PiaMan, Nov 28, 2017
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  9. Brett Horton

    Brett Horton Active Member

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    You using 5 or 6?
    Brett Horton, Nov 28, 2017
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  10. PiaMan

    PiaMan Active Member

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    Scn5 150mm. Im pretty light at about 150lbs. I dont share my scn system much with friends so cant comment on much heavier user response but the few who have tried it i dont see a difference. I spent enough on my main rig that i dont want to see anything fail because i shared it.
    • Like Like x 1
    PiaMan, Nov 28, 2017
    #10
  11. gSeat

    gSeat Member

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    Side question - I bought worm gears because of the roughly $200 savings per axis.
    As a first time sim build I'll still be blown away right :) ?
    Looked into SCN 6 and came across "noise complaints..." that didn't deter the choice too much since will use oculus headset, it was more about price and it seemed like I could make a smaller base footprint.
    gSeat, Nov 28, 2017
    #11
  12. Brett Horton

    Brett Horton Active Member

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    You will be amazed....
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    Brett Horton, Nov 28, 2017
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  13. Brett Horton

    Brett Horton Active Member

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    Very good resolution IMO, these are 25:1

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    Brett Horton, Nov 28, 2017
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  14. Zed

    Zed VR Simming w/Reverb Gold Contributor

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    Yep - that's what I have too. Thanks! I can't pull a motor tonight to check end play but will. I'm hoping that's where the backlash is coming from since that would be an easy fix - just throw in some washers to minimize it.
    Zed, Nov 29, 2017
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  15. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    The average backlash is there by design for lubrication purposes, there is not much to fix unless it is outside design parameters.

    You could try a smaller lever CTC, you will loose some speed, gain some torque and reduce how noticeable the backlash is. A small amount of pre-load weight rather than perfect rig balance will also help reduce how noticeable the backlash is.
    • Informative Informative x 2
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    Last edited: Nov 29, 2017
    noorbeast, Nov 29, 2017
    #15
  16. Zed

    Zed VR Simming w/Reverb Gold Contributor

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    Well rats. I may still see about shimming end play on the worm if there is any even at the expense of lubrication. Or, worst case I start mulling over different actuators. I would like to get rid of the clicking.
    Zed, Nov 29, 2017
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  17. Limongi

    Limongi Member

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    I'm trying to figure out a 3D printed surround for the pgsaw motor to isolate the clickity clacking. I'm thinking of a simple layering of ABS and rubber would at least be able to cut the noise in half if done well.

    This does nothing for backlash physically, but if you wanted to do that, the large spur gear needs to be replaced with a split spur gear. I would assume this modification would have a great deal of extra friction and as such the additional mechanical loss may not be worth it but I wouldn't know. I would also guess a split gear would be very high wearing to the worm gear in setups like ours. If someone has experience and the right mill it would be worth it but if not a DIY endeavour a machine shop would likely charge more per hour than the pgsaw motor costs in the first place.

    If I make a silencer that works I'll post a thread.

    Attached Files:

    • Creative Creative x 1
    Limongi, Dec 1, 2017
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  18. Limongi

    Limongi Member

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    • Like Like x 1
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    Limongi, Dec 2, 2017
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  19. adgun

    adgun Active Member

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    You need a wormwheel not a spurgear
    just my 2 cents
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    adgun, Dec 2, 2017
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  20. Limongi

    Limongi Member

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    Limongi, Dec 2, 2017
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