Features of the RollerDrive A roller mechanism with good transmission efficiency and zero backlash

  • A roller drive is a highly efficient reducer of power transmission speed that uses the contact between the roller gear cam and the roller follower to slow the motion down to the desired speed.
    Using worm gears does not remove backlash, but the RollerDrive ends backlash completely by placing a preload on the follower roller.
    As compared with other reducers, it has better transmission efficiency, longer mechanical life, and higher holding strength against external forces. The RollerDrive is not only employed in reducers but also in a wide range of other applications, including high precision positioning tables, rotary cores in processing machines, and articulating robot joints.

Comparison of rolling and sliding mechanisms

  • RollerDrive

    Multiple roller followers and roller cams can efficiently engage under preloaded conditions, so it provides accurate transfer without backlash.
    There are only the smallest of errors in both the clockwise (CW) and CCW directions, for stable motion.

  • Worm gears

    Play is required between the gears so they can rotate. This necessary play allows unwanted looseness to enter the system.
    There are many errors in both the CW and CCW directions.

Heavy-duty cutting and high-precision processing RollerDrive can stand up to heavy-duty cutting

  • RollerDrive is very rigid,
    and makes it possible to
    perform heavy-duty cutting and
    high precision processing in a wide
    array of processing fields.

Processing examples

  • RollerDrive

  • Worm gears

Maintenance-free with high performance over low cost

  • Maintains overwhelming accuracy

  • Torque is transferred by rolling contact, so that the internal mechanism does not wear; long-time use does not cause precision to deteriorate from the initial level.
    <Driving conditions>
    Table size: Output table diameter: 170mm
    Load inertia: 0.5kg・m2
    Indexing angle: 36° (one-direction indexing)
    Indexing time: 0.35sec

    <Accuracy after 5 million indexing operations>

    Item Worm gears RollerDrive
    Change in
    accuracy    		 42.1sec
    (assuming no
    maintenance)    		 0.9sec
    Amount of
    backlash    		 18μm 0

    *The data in the left-hand graph are actually-measured RollerDrive values obtained during test driving.
    (Both companies used test machines with the same table diameters)

  • Variation of positioning precision due to aging

  • ・Production efficiency drops as maintenance is required to deal with changes in precision.

    ・RollerDrive does not require any maintenance. It can keep operating in the production line, stably, with high precision and without any downtime.

  • Cumulative total of initial price plus annual maintenance costs

  • CNCs with integrated RollerDrives induce very little variation due to aging, so periodic maintenance costs are considerably reduced.
    This graph was drawn on the basis of these assumptions:

    ・A worm gear driven circular table requires maintenance twice a year.

    ・These two maintenance activities combined (changing oil, etc.) cost 3% of the cost of the gear per year.

    *The both cases tables with the same diameter were used.

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