technical data Coupling Selection and Procedure

If you would like to see the selection procedures and important points, please proceed below.

If you would like to narrow down or tentatively select a product series,
Please click here.

To Selection Guide

If your usage conditions have been decided and you would like a detailed selection,
Please click here.

To sizing

Jaw-Flex Coupling LN Series Selection

To use Jaw-Flex Coupling LN Series for a long period of time without backlash, it is necessary to provide a sufficient safety margin for the spider's normal operating torque.

Therefore, please follow the steps below when making your selection. Spiders are consumable items, so regular inspections are required to maintain a non-backlash state.

  • 1. Using the driver's transmission power P (kW) and the coupling's operating rotational speed n (r/min.), calculate the torque T (N m) applied to the coupling using the formula below.

    T = 9550・P/n

  • 2. Determine the service factors St and Sd based on the operating conditions, and calculate the correction torque Tr (N m) applied to the coupling.

    Tr = T・St・Sd

    • St: Temperature coefficient
    • Sd: Torsional rigidity coefficient

    Select the size so that the normal torque Tn of the coupling is equal to or greater than the correction torque Tr.

    Tn ≧ Tr

    Temperature coefficient
    Operating temperature ℃ Temperature coefficient St
    -30 ～ +30 1.0
      ～ +40 1.2
      ～ +60 1.4
      ～ +80 1.8
    Torsional stiffness coefficient
    application Torsional stiffness coefficient Sd
    machine tool spindle 2 ～ 5
    Positioning 3 ～ 8
    Encoder 10 or more
  • 3. Make sure that the maximum torque Ts (N m) generated from the drive side, load side, or both is less than the normal torque Tn of the coupling.
    • Maximum drive torque: Ts = Tas・Ma・Sa
    • Maximum load torque: Ts = Tℓs・ML・SL
    • Tn ≧ Ts・St・Sd
    • Tas: Maximum driving torque (N・m)
    • Tℓs: Maximum load torque (N・m)
    • Ma: Drive side moment of inertia ratio Ma = Jℓ/ (Ja + Jℓ)
    • Mℓ: Load side moment of inertia ratio Mℓ = Ja/ (Ja + Jℓ)
    • Sa: Impact load coefficient (drive side)
    • Sℓ: Impact load coefficient (load side)
    • Ja: Drive side moment of inertia
    • Jℓ: Load moment of inertia
    Impact Load Factor
    Load Nature Impact load factor Sa(Sℓ)
    Uniform Load 1.0
    Small fluctuations 1.4
    Large fluctuations 1.8
  • 4. Make sure that the mounting shaft is within the range of shaft diameters that can be mounted on the coupling.
    The shaft tightening torque varies depending on the shaft diameter, so it may be lower than the spider's normal torque.
    Make sure that the shaft fastening torque of the selected coupling size is equal to or greater than the maximum torque Ts applied to the coupling.