Epicyclic gear set NVH analysis

Epicyclic gear set NVH analysis

Epicyclic gear set NVH analysis


Epicyclic gear sets, also known as planetary gear systems, are commonly used in the transmission systems of vehicles and machinery. Their unique design allows for high gear ratios in a compact package. However, one of the main challenges in implementing these gear sets is managing the noise, vibration, and harshness (NVH) that they can produce. In this article, we will explore some of the methods for analyzing and reducing NVH in epicyclic gear sets.

Overview of epicyclic gear sets

An epicyclic gear set consists of three main components: a sun gear, one or more planet gears, and a ring gear. The planet gears are mounted on a carrier that rotates around the sun gear, while the ring gear is fixed in place. By varying the input and output connections, the gear ratio can be adjusted. Epicyclic gear sets are often used in automatic transmissions, where the gear ratio needs to be continuously adjusted based on the vehicle speed and load.

NVH sources in epicyclic gear sets

There are several sources of NVH in epicyclic gear sets:

  • Gear meshing: the contact between the gear teeth can produce noise and vibration.
  • Bearing noise: the rolling elements of the bearings can generate noise and vibration.
  • Vibration transmission: the gear set can transmit vibration to other components in the system, leading to additional noise and vibration.

NVH analysis techniques

There are several techniques for analyzing NVH in epicyclic gear sets:

  • Modal analysis: this technique involves measuring the natural frequencies and mode shapes of the gear set and surrounding components. This can help identify which components are contributing to the NVH.
  • Frequency analysis: this technique involves measuring the frequency spectrum of the noise and vibration. This can help identify the dominant frequencies and harmonics, which can then be targeted for reduction.
  • Dynamic simulation: this technique involves simulating the gear set and surrounding components in a dynamic simulation tool, such as finite element analysis (FEA) or multibody simulation. This can help identify areas of high stress and deformation, which can lead to noise and vibration.

Reducing NVH in epicyclic gear sets

There are several methods for reducing NVH in epicyclic gear sets:

  • Tooth profile optimization: modifying the tooth profile can reduce gear meshing noise.
  • Bearing selection: choosing bearings with lower noise and vibration characteristics can reduce bearing noise.
  • Damping: adding damping materials or structures can absorb vibration and reduce noise.


NVH is a significant concern in the design of epicyclic gear sets. However, with the right analysis techniques and design modifications, it is possible to reduce the noise and vibration to an acceptable level. Our company specializes in producing high-quality epicyclic gear sets and planetary gear systems. With over 300 sets of fully automated CNC production equipment and automatic assembly equipment, we are a leading manufacturer in the Chinese gear market. Our products include epicyclic drive, Epicyclic Gearing, planetary box, precision planetary gear motor, planetary gearhead, sun planet gear, and planetary gearbox motor. We pride ourselves on our commitment to providing top-quality products, competitive prices, and excellent customer service. We welcome customization requests and look forward to working with you.

Author: Czh