Difference between Flat Belt and V-belt drives


This topic contains 8 replies, has 6 voices, and was last updated by  Sanikapatel 2 weeks, 3 days ago.

  • Author
  • #2024

    leela kishore
    Points: 75

    what is difference between ordinary belt and v-belt. What is the property that makes v-belt to transmit more power.


    Surjeet Sankararaj
    Points: 627

    Ordinary belt (flat belt) has a rectangular cross section while V-belt has a trapezoidal cross section. Because of the trapezoidal cross section, V-belt drives are capable of transmitting more power by wedging action between the belt and the V-groove in the pulley. Multiple V-belts are capable of transmitting even more power.
    Multiple V-belts
    Poly V - belts


    Points: 29

    Hello Surjit
    I m an energy technology (M.Tech) student with electrical(B.Tech) background. I’ve read (casually, HABASIT company) about the modern synthetic flat belt being more efficient(3% to 6% points) than a V-belt for the same application(experiments)… Can you please write on it(explain to me), when to use flat belt(modern one)/V-belt? …
    Further—-Nowadays, related energy audit report’s recommendations include the replacement of the existing V-belt drive by a suitable Flat-belt(synthetic one) drive for energy conservation. Please, justify the above context considering mechanical point of view (Technical/”Power transmission”).

    Thanks in anticipation.


    Surjeet Sankararaj
    Points: 627

    Dear sromen24
    In my reply I was comparing conventional flat belts with V-belts. V-belts are always more efficient than conventional flat belts. However, this advantage comes at an expense. V-belts have more mass when compared to conventional flat belts. Also they have higher bending loss (a type of loss that occurs whenever the belt bends over the pulley). In spite of these disadvantages, V-belts were preferred to conventional flat belts because their slip is almost negligible. Slip is the relative motion between the belt and pulley. It is something that must be avoided at all costs (in belt drives). In V-belt drives, slip is kept under control because of wedging action between the belt and V-groove in the pulley.

    I just read about the modern synthetic flat belt (Habasit polyamide high effi-
    ciency flat belt) you are talking about. It seems to be using materials with high tensile strength and high friction. This would definitely reduce slip in the belt. Also it has less mass and bending loss when compared to V-belt. I think these are the main reasons why it has greater power transmission efficiency.


    Points: 29

    Good Morning, Surjeet S
    Thanks for the information…
    I am working on some energy conservation interventions in electromechanical system: I may need lots of knowledge on Mechanical drives. I find this site very energetic and knowledge-full, should i need to clear doubt, i ll contact again.
    Take care.


    Points: 45

    v-belt provide more contact surface between pulley and belt compare to flat belt for same width .due to more contact surface more frictional force induced if tension,coefficient of friction and contact angle is same.hence v-belt is more efficient than flat belt because due to more friction lees sleep between belt and pulley will takes place.


    Points: 29

    Hello Surjeet,
    In the Book “Design of Machine elements” by VB Bhandhari, the arc of contact factor, Fd is multiplied with the rated power while as per the formula you’ve referred in the page “”How to Design a Flat-belt Drive””, the said factor divides the rated power. i.e.
    [Corrected Power= {(load correction factor x rated power) x arc of contact factor}]—VB Bhandhari
    [Design Power={(rated power/arc of contact factor) x other factors}]….http://mechteacher.com/flat-belt-design/2/#
    Please clear me this confusion I m having with.
    I am just an Electrical Engg. Student working on the flat belt drives.
    Thanking you in anticipation.


    Points: 95

    According to the notes offered by my professor, the formula for design power found in the page http://mechteacher.com/flat-belt-design/2/# is correct. If the arc of contact factor is multiplied in the numerator as per your book, the values for arc of contact factor as per your book would vary when compared to the values found in http://mechteacher.com/flat-belt-design/2/#


    Points: 57

    Which one is mostly used between both??


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