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Ball Splines

To view more information on ball splines select any of the manufacturer's logos below. Contact us for any further questions or to request a catalog. 

IKO Nippon Bearing

Highly accurate, dependable, and rigid components. Assemblies capable of high speeds, high acceleration and deceleration with smooth movement. Machined ends, seal kits, and more also available for the best set up and longest life of your components. Request a quote.

Description: A Ball Spline is a linear motion system in which balls contained in the spline nut transmit torque while linearly moving on precision-ground raceways on the spline shaft.

 

ballspline

Ball Splines


    IKO

  • C-Lube Linear Ball Spline MAG
  • Linear Ball Spline G
  • Block Type Linear Ball Spline
  • Stroke Ball Spline

NB

  • Ball Spline
  • Rotary Ball Spline SPR
  • Rotary Ball Spline SPB
  • Stroke Ball Spline
  • Ball Screw Spline


Load and Accuracy Factors

  • Ball contact

    • Number of grooves in the shaft
      • Grooved spline shafts give greater contact areas making load capacity and life greater than a like sized slide bush and shaft combination. Basic dynamic load ratings of a ball spline are typically 5~12 times that of a slide bush of a similar size. Number of grooves in a spline can range from two to six, with six groove systems taking up much of the space on the shaft that there is not enough room next to the nut's active ball paths for recirculation of the balls. When six grooves are necessary, the nut must protrude from the shaft for the balls to be above and away from the shaft for recirculation. Four groove configuration is the most popular and he nut can have side by side active and recirculating paths eliminating the extra space needed for larger amounts of grooves and making it a more compact system.

    • Shape of the grooves
      • The standard shape of grooves is between two choices -- balls that make contact with with the raceway grooves at two points those that make contact at four points. When there is a slightly elliptical groove design it allows the balls to make contact at two opposing points but allows a bit of clearance on the balls' sides that are perpendicular to the contact points. The four point contact is called a "gothic arch" and it eliminates any clearance that could lead to deflection and it best suited for applications that require maximum precision. Another shaft configuration available for very high loads uses a semi-triangular protrusions along the spline shaft, but it comes with a drawback -- it is more difficult to machine the ends of the shaft and is less stiff.

    • Length of the nut and raceways
      • Around half of the balls in the raceway are always in the active, load-bearing portion of the raceway leaving the other half to be in the recirculating path. To gain more active balls to support the load, the nut length needs to be increased. There are some raceways that are designed to be more efficient when taking the nut's length and putting more balls into it's active portion. With more balls in the active part of the nut, the more moment load the nut can support. Multiple nuts can be used in tandem to increase moment load.

    • Nut tolerance
      • Preloading decreases the available radial play ensuring higher rigidity which in turn increases precision. Increasing the contact areas and and direct loading capabilities, also restricts radial movement while also increasing the overhung moment capabilities. The result -- a sturdier structure that can handle a very demanding working environment. For a load where minor twisting, altering moment load and vibration, a light preload is preferable.

  • Shaft Rigidity
    • Symmetry of the spline shaft can increase maximum rotational speed and load capacities as well as reduce vibration. Spline shafts vary as to whether they are precision-ground, ground, or drawn steel bar. Non-ground (drawn) spline shafts are naturally of lower accuracy. Manufacturers generally offer three different classes of accuracy: High (highest precision), Medium (standard grade, typically a stock item), and Low (often a non-ground shaft). Comparing accuracy grades comes down to comparing the measurements of shaft diameter tolerance, straightness, perpendicularity and concentricity. Non-ground shafts are a good choice when a lesser degree of accuracy is acceptable. The are lower in cost, and perfectly acceptable for material transfer and handling applications.

  • Mounting systems
    • Accuracy will be affected if a load is not mounted to the nut securely. There are three types of mounting systems that are commonly used:

      • Nut with a Keyway -- The standard mode of mounting a cylindrical nut is with a key. This system contains the cylindrical nut that will have a keyway and a separate key. Matching keyway must be bored into the housing or block that will be mounted on the cylinder nut. The bore's precise fit is critical to prevent vibration. This system also requires a snap ring, a push plate, or another fixing method to prevent the nut from slipping out of the housing.
      • Nut with Flange -- Flange nuts are more simple to install simply because they only require a a rough bore and mounting holes drilled and tapped to secure the flange to the housing. Flange types are bolted on to the housing therefore there is no need for a keyway.
      • Keyless Nut -- Keyless cylinder nuts is suitable for small size and compact applications. Similar to a flange type nut, but instead there is a squared attachment that is slotted onto the nut to prevent rotation. The slot can be made with holes for screws to fix the nut similarly to the way a flange is fixed to housing but is much more compact than the standard flange.

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