NVH Optimisation - Transmission

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Customer: Tier 1 supplier to the automotive industry

Market: Light duty on highway - Asia

BRACE execution: Powertrain domain cluster

Location: Customer site and OEM site (end customer)

Noise Vibration and Harshness can cause serious annoyance at the vehicle end user. Field complaints often occur because of this, therefore NVH in relation to Gears & Bearings is one of the fields of expertise within the BRACE crew.

BRACE analyzed field complaints at the OEM customer of the BRACE client caused by NVH problems. The major difficulty lies in the fact that the BRACE client is only supplying transmissions and therefore is only responsible for transmission related NVH. Since the vehicle itself has a very big effect on the NVH behavior, possible improvements are a big challenge. To apply the research in the right way and maximize the benefit the focus is divided on multiple ways to improve:

  • Measurements (done in cooperation with external partner’s facilities)

    • Noise level (microphones, at different positions in anechoic test chamber)
    • Vibration (excitations in all direction at bearings and mounting points)
    • Radiated noise (acoustic camera)
    • Housing deflection
    • In vehicle noise @ passenger seat’s head rest (@ client location)
    • On vehicle vibrations (@ client location)
  • Transmission housing simulations for dynamic behavior (with partner)

    • modal analyses,
    • frequency response,
    • ERP-level (Equivalent Radiated Power).
  • Gear mesh optimization simulations (with partner)

    • Gear mesh misalignment study
    • Transmission error (TE)
    • Contact pattern
    • Micro geometry optimization

BRACE managed to get to an acceptable noise evaluation score (level), using their result driven approach in close collaboration with all partners.