Thrust transfer between shaft and output coupling on a V drive

Discussion in 'Inboards' started by Scrumble, Jan 1, 2010.

  1. Scrumble
    Joined: Aug 2008
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    Location: Darwin, Northern Territory, Australia

    Scrumble Oram 46'C MS Builder

    Thrust transfer between shaft and output coupling on a ZF 15 MIV V drive

    Good Day,

    Could anyone please advise me on the correct way to fit coupling to shaft for a ZF 15 MIV (V drive output through through the gearbox). So far, what I have seen appear to be like a straight shaft arrangement, not tapered for the thrust, seemingly with the thrust transferred through the set screws???. Please tell me that I have got this wrong and that something like a shaft taper or internal flange within the coupling is used.

    Regards,
     
    Last edited: Jan 2, 2010
  2. Jango
    Joined: Aug 2005
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    Location: Mid Atlantic

    Jango Senior Enthusiast

    I have never seen any type of tapered shaft arrangement at the gearbox or Vee Drive. Most Shaft couplings have two setscrews only, whereby the shaft should be spotted 1/16 to 1/8 deep at the screws with a drill to insure adequate set screw holding. Also a good idea to use "locktite" or a similar product.
     
  3. Scrumble
    Joined: Aug 2008
    Posts: 27
    Likes: 3, Points: 0, Legacy Rep: 75
    Location: Darwin, Northern Territory, Australia

    Scrumble Oram 46'C MS Builder

    Thrust transfer between shaft and output coupling on a ZF 15 MIV V drive

    Good Day Jango,

    Thank you for your reply, I need to clarify that the ZF 15 MIV has the shaft coming through the gearbox and therefore the coupling is reversed and the thrust is away from the forward side of the gear box.
    This would mean if the shaft is straight, only the set screws would be taking the thrust which I believe could never be condoned.

    I believe this shaft set up requires a forward taper into the coupling, however I don't have any documentation to indicate what is the correct approach.

    I am certain and will use the fact that the coupling does not have to be removed from the shaft because the flange bolts can be undone and the shaft and coupling pulled forward into the boat. This in my case will be through a 150mm inspection port into another compartment forward of the engine compartment.

    Regards
     
    Last edited: Jan 2, 2010
  4. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    There is no taper. It is an interference fit (tight). The set screws are enough. Millions of boats use that setup with no problem
     
  5. Scrumble
    Joined: Aug 2008
    Posts: 27
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    Location: Darwin, Northern Territory, Australia

    Scrumble Oram 46'C MS Builder

    Good Day Gonzo,

    Thank you very much.

    Regards,
     
  6. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    You are welcome. They don't seem that they would hold, but they do.
     
  7. Frosty

    Frosty Previous Member

    What looks like a set screw on the gearbox output flange is a set screw to hold the lock nut on the end of the key and taper.

    With a proper arrangement you wont need to worry about anything, including the shaft disappearing out of the back of the boat when selecting reverse.

    Unfortunately that what will happen if it does come loose.
     
  8. Scrumble
    Joined: Aug 2008
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    Location: Darwin, Northern Territory, Australia

    Scrumble Oram 46'C MS Builder

    Thanks Frosty,

    I am happy with the interference fit as I may never have to take the coupling off.
    I will also ensure the set screws are set in properly and lock-wired and most particularly will drill through the coupling and 1 1/4" shaft for a fine retaining bolt.

    Happy New Year, regards,
     

  9. halo64
    Joined: May 2011
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    Location: houston

    halo64 halo64

    does any one know how to check the v drive out put coupling

    i have a carver montego and its loose how can i check for the problem safely
     
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