Belt Drive in machine design Definition, Types, applications, Advantages & Disadvantages

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BELT DRIVE SYSTEM


  • Definition :

    • A mechanism which transmit power from one shaft to another by using Pulley as the movement of continuous flexible belt, called Belt drive.

  • Functions :

    • Belt drive is power transmitting mechanism.

    • Belt is used to transmit power between shafts by friction.

    • It transmit power over considerable distance.

    • It is also called as a flexible drive.

    • It has ability to absorb shock & vibration.

  • Key Points :

    • Design of belt drive depends of selection of belt and corresponding pulley from manufacturing catalogue.

    • In belt drive the belt is an Intermediate link.

  • TYPES OF BELT DRIVE :

    Diagram of different types of belt drives including open belt drive and cross belt drive.
    Fig 1 : Types of belt drive


    • OPEN BELT DRIVE :

      • An open belt drive is that type of belt drive where one pulley top is connected to another pulley top through belt & without crossing in it.

      • In open belt drive both Driver & Driven pulley rotates in same direction.

      • Limitations:

        • Extra long centre distance causes vibrations.

        • Very small centre distance causes slip in belt.




    • CROSSED BELT DRIVE :

      • A Crossed belt drive is that type of belt drive where one pulley top is connected to another pulley bottom through belt & with crossing in it.

      • In Crossed belt drive Driver & Driven pulley rotates in different directions.

      • Limitations:

        • Used for only shorter distance.




    • COMPOUND BELT DRIVE :

      • Definition :

        • A compound belt drive is an arrangement in which power is transmitted from one shaft to another through one or more intermediate shafts.

        • The velocity ratio is the product of the individual velocity ratios of the belt drive.

        • It consist of one or more intermediate shaft carrying pulley, where one pulley acts as a driver pulley and the other as a driven for the next stage.

        • Limitations :

          • Power loss due to multiple belts, causes high amount of slip & creep.

          • Complicated design due to multiple shafts and pulleys arrangement.

          • Requires frequent maintenance.

          • Occupy more space.

          • Not suitable for high power transmission.




    • QUARTER TURN BELT DRIVE :

      • A quarter turn belt drive is a type of belt drive, used to transmit power between two shafts whose axes intersect at 90°.

      • It is known as right angle drive.

      • They are perpendicular to each other.

      • For smooth running, the pulley on the upper shaft is placed exactly above the centre of the lower pulley.

      • The upper pulley must be placed vertically above the centre of the lower pulley.

      • Limitations:

        • If the pulley is not aligned properly, the belt may run off the pulley.

        • Wear of belt in edges due to twisted at 90°.

        • Not suitable for high speeds transmission.

        • Alignment of pulleys and proper tensioning required.

  • TYPES OF BELT :




    • FLAT BELT :

      • Definition :

        • A flat belt drive is a mechanical system used to transmit power between to parallel shafts by means of a flat, feasible belt running over pulleys.

        • Traditional & simple method for power transmission.

        • When the driver pulley rotates, the rotation causes to rotate the driven pulley through flat belt.

        • Advantage :

          • Simple design.

          • Quiet operation at moderate speed.

          • Less – expensive

        • Limitations :

          • Slip & Creep reduce velocity ratio.

          • Not suitable for high speed vehicle.

          • Belt material may streached.

    • V-BELT DRIVE :

      • Definition :

        • A V-belt drive is a power transmitting system using a trapezoidal (v-shape) belt running in a grooved pulley.

        • A trapezoidal (v-shaped ) cross-section runs in a matching grooved pulley.

        • The wedging action of the belt in the pulley groove increase the frictional grip, making it more efficient than flat belt drive.

        • Advantages :

          • Higher power transmission capacity.

          • Almost zero slip.

          • Suitable & compact for short distance.

          • Using of multiple v-belt for more power transmission.

        • Limitations :

          • Not suitable for long distance.

          • Required accurate belt alignment.

          • Initial cost is High.

    • TIMING BELT :

      • A Timing belt is a special type of belt has teeth ( cogs) on its inner side.

      • These teeth fit into matching grooved on pulley.

      • This is positive engagement these is no slip between the belt & pulley.

      • Application :

        • Internal combustion engines

        • Robots, Printer, & Textile machine.


    • ROUND BELT :

      • A Round belt has a circular cross-sectional.

      • Usually made of rubber or polyurethane.

      • It transmit motion between pulleys through friction.

      • Key Points :

        • Simple light weight.

        • It can work with twisted belt layout.

        • Easy to install and inexpensive.

      • Limitations :

        • Not suitable for high Power transmission.

      • Application :

        • Sewing machine.

        • Vacuum cleaner.