What is the recommended hub length in relation to the face width of the gear?

In the context of gear design, the recommended hub length should be related to the face width of the gear to ensure proper support and strength of the gear assembly. The correct answer reflects a recommendation that the hub length be approximately twice the diameter of the shaft. This guideline is based on providing adequate support for the gear while allowing for optimal load distribution and minimizing bending moments that can occur due to external loads.

Having a hub length that is around twice the shaft diameter ensures that the gear is sufficiently supported on the shaft. This approach helps in maintaining proper alignment and preventing excessive wear or failure during operation. If the hub length is too short, it may not adequately support the gear, leading to potential issues such as misalignment or uneven loading, which can affect performance and longevity.

In summary, the recommendation for the hub length being approximately twice the shaft diameter is crucial for maintaining the integrity and effectiveness of the gear system, while also accommodating factors like loading conditions and manufacturing tolerances.