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Belts or Chains

Last post 12-06-2013 01:20 PM by martindemo. 12 replies.
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  • 12-03-2013 11:10 AM

    Belts or Chains

    hi guys  do all scooters use belts? why not chains like most bikes? i read in really hot wheather belts can split and i think a chain would last longer .

  • 12-03-2013 12:13 PM In reply to

    • vortexau
    • Top 75 Contributor
    • Joined on 10-25-2008
    • Plainland Q, on the Warrego Hwy
    • Posts 462

    Re: Belts or chanes

    The "belt" in use on many modern scooters is part of the CVT unit, when the output shaft lines up with the rear axle.  Do YOU advocate building CVT units with chains rather than belts?  How would you get a chain to connect with a "sprocket" that changes in diameter to vary the gearing ratio?

    normal scooter CVT

    THIS may look like a "toothed" belt drive but its actually a friction belt running between two pulleys which vary in diameter to produce a seamless gearing ratio between engine output shaft and the rear axle.

     

    Larger capacity maxis can site the engine further forward (motorcycle fashion) and these scooters do employ a separate FINAL drive; which, in the case of the Burgman 650, consits of a gear-train running in an oil bath:

    Burgman gear-train drive

     

    The new BMW maxis employ a fully-enclosed chain final drive:

    BMW final drive

    __________________
    Marty McFly:
    Does it run like on, on regular unleaded gasoline?
    Dr. Emmett L. Brown:
    Unfortunately, no. It requires something with a little more kick . . . plutonium!
  • 12-03-2013 12:51 PM In reply to

    Re: Belts or chanes

    QUOTE: How would you get a chain to connect with a "sprocket" that changes in diameter to vary the gearing ratio?

    Dunno, but I believe that the "CVT" automatic gear box in the latest Subarus is chain driven.

    You can see a video here: http://www.subaru.com/engineering/transmission.html

     

    I refuse to grow old until I grow up.
    Growing up is for people with nothing better to do with their lives.
  • 12-03-2013 03:14 PM In reply to

    • CrazyCam
    • Top 150 Contributor
    • Joined on 04-15-2013
    • Beecroft, NSW
    • Posts 211

    Re: Belts or chains

    The big 850 Aprilia scoot has an exposed chain drive.

    I have no idea how it works.

     

    Warning: Posting may contain traces of sarcasm and/or nuts.

    regards, CrazyCam
  • 12-03-2013 03:44 PM In reply to

    Re: Belts or chains

     As said above  a CVT needs a belt to work as regards belt or chain final drive believe a chain is the most efficient

  • 12-03-2013 03:56 PM In reply to

    Re: Belts or Chains

    does that Mean the BMWs run on a belt for the lower gears then a chain for the final drive?

  • 12-03-2013 04:08 PM In reply to

    Re: Belts or Chains

    Hi      Sorry i forgot to say i Like the look of the drive Train that the burgman use . But how long would that setup last?

  • 12-03-2013 09:46 PM In reply to

    Re: Belts or chanes

    Vampire:

    How would you get a chain to connect with a "sprocket" that changes in diameter to vary the gearing ratio?

    Dunno, but I believe that the "CVT" automatic gear box in the latest Subarus is chain driven.

    You can see a video here: http://www.subaru.com/engineering/transmission.html

     

    Why would you go to the expense, weight and complexity of a chain when a belt does the same job. It's quite easy to change over and does what is required. Cars uses chains because of the torque it needs to withstand. Don't see many scooters pumping out 250+Nm as well as towing 1500kg. Sometimes simplicity and fit-for-purpose is all that is needed on these simple devices.

  • 12-03-2013 10:14 PM In reply to

    • INMA
    • Top 50 Contributor
    • Joined on 03-19-2009
    • Posts 844

    Re: Belts or chanes

    Our scooters use a belt drive system that was first patented by DAF for use in small cars.

    The variable belt drives are a reasonably cheap and reliable transmission for vehicles with modest horsepower.

    The variable machine geometry of the DAF systems has been adapted to other friction drives in continuously variable transmissions use in many modern cars.  the modern car syatems use friction drives with cones and chains and balls doing the same ratio changes as the belts inside oil bath syatems.  The oil is needed to reduce wear due to the extreme contact pressures and forces on the friction drives.

    The cost of the bigger car and SUV CVT drives is significantly higher and would not be as profitable on our low cost scooters.  There may be some CVT s used in older mopeds and the Sachs Madass 50cc.

    For what we need, the variator, torque driver, clutch and final drive are remarkably good durable and cheap.

    2001 Yamaha Zuma, DR Evo 68 cylinder, Leo Vince TT derestricted, Delorto 17.5 (#98 jet), standard aircleaner, RMS fan, Race CDI, Standard oiler and premix @ 75:1 Shell SX2, Doppler SR3 variator, RMS clutch, RMS R rear shock absorber and Pirelli SL26 tyres.
  • 12-04-2013 06:27 PM In reply to

    Re: Belts or chanes

    Anyone care to hazzard a guess at what the power losses would be in the Burgman drive train with three idler gears in an oil bath?

    You're as bad as me, you used to be so much better, that makes you worse.

    Red Gilera Fuoco 500ie
  • 12-05-2013 07:05 PM In reply to

    • vortexau
    • Top 75 Contributor
    • Joined on 10-25-2008
    • Plainland Q, on the Warrego Hwy
    • Posts 462

    Re: Belts or chanes

    Likely not enough to cause any concern.  The export model (Burgman) employs straight-cut gears for maximum efficiency, while the Japanese domestic model (Skywave) employs helical-cut gears for a lower noise level of opperation.

    Gear trains (driving camshafts & axiliary components) have often been the choice for reliability, and high output efficiency, in both racing engines and military applications.  If cost and noise are not considerations, then a total gear train can be used for various power transmission routes.

    If cost and noise are not considerations, then a total gear train can be used for cam drives

    Read more: http://www.physicsforums.com

    submarine engine gear train

    Geartrain camshaft drive on GM submarine diesel engine

     

    1926 DeLange gear train

    Geartrain on 1926 DeLange, and (underneath) Cosworth V-8 F1 engine: Cosworth V-8 F1 engine

    Cosworth V-8 F1 engine

    Read more: http://www.physicsforums.com

     

     

    Conversely, in begone era employing multiple drivechains was not uncommon in various vehicle designs:

    Frazer-Nash chassisdrivechain gearbox

     

     

     

     

     

    Cosworth V-8 F1 engine

    Read more: http://www.physicsforums.com

    Cosworth V-8 F1 engine

    Read more: http://www.physicsforums.com
    Cosworth V-8 F1 engine

    Read more: http://www.physicsforums.com

     

    Cosworth V-8 F1 engine

    Read more: http://www.physicsforums.com

    __________________
    Marty McFly:
    Does it run like on, on regular unleaded gasoline?
    Dr. Emmett L. Brown:
    Unfortunately, no. It requires something with a little more kick . . . plutonium!
  • 12-05-2013 07:44 PM In reply to

    • vortexau
    • Top 75 Contributor
    • Joined on 10-25-2008
    • Plainland Q, on the Warrego Hwy
    • Posts 462

    Re: Belts or Chains

    jpfvita:

    Hi      Sorry i forgot to say i Like the look of the drive Train that the burgman use . But how long would that setup last?

    Longer than several belts, and multiple chains.  Unlike a normal manual gearbox with different ratios of cog-to-cog power transmission the gears in this drivetrain remain in contact.  Someone once remarked that the odd number of gears employed meant a change of direction of rotation from driving end to driven end.

    What does one find inside a normal differential housing?

    Additionally, the style of CVT belt that Suzuki uses in the transmission is termed a "Dry Hybrid Belt, which is built using rubber tension members embedded in H-shaped, high-strength aluminium blocks covered with resin. Lightweight and designed to run dry (instead of an oil bath which increases frictional losses), the belt is the secret to the incredible precision of the Suzuki SECVT."  This item was used for low power loss, and LONG life.

     

     

    __________________
    Marty McFly:
    Does it run like on, on regular unleaded gasoline?
    Dr. Emmett L. Brown:
    Unfortunately, no. It requires something with a little more kick . . . plutonium!
  • 12-06-2013 01:20 PM In reply to

    Re: Belts or Chains

    Belts or Chains??

    Interested to try, but I've never found a willing partner.

    Aprilia 200ie
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