Explanation of the Adapter Flange for Installing a Harmonic Gearbox to a Motor

Recently, we have received feedback from some customers who found that the harmonic gearbox and motor they selected could not be directly installed together, requiring an adapter flange. However, they could not find such a product on our website. Below is a detailed explanation.

In many automation projects, robotics R&D, or high-end equipment, engineers often need to design their own mounting flanges. This is mainly determined by the following core reasons:

1. Inconsistent Industry Standards (Diverse Mounting Dimensions)

• Different motor dimensions: The pilot diameters, shaft diameters, locating pin holes, and pitch circle diameters (PCD) of servo motors and stepper motors vary across different brands.
• Different harmonic gearbox models: Harmonic gearboxes come in various types, such as component type, mini type, and hollow shaft type, each with different input-side mounting dimensions. For example, our harmonic series currently includes many types: HHD, HHT, HSS. Each series is further divided into different size sub-series, involving a wide variety of mounting dimensions.

2. Requirements for Compact Equipment Space

• Limited axial space: Standard off-the-shelf connecting flanges are typically made relatively thick for compatibility. In lightweight robotic arms or joints, such flanges are simply unusable.
• Integrated structural requirements: Often, the flange is not just a "connector"; it also needs to serve as a motor base, support frame, cable outlet, or even an air passage. Especially in highly integrated non-standard structures like robotic arms, the flange can only be custom-designed according to the overall equipment's needs.

3. Special Operating Conditions for Heat Dissipation and Sealing

• Heat dissipation requirements: Harmonic gearboxes generate significant heat during heavy-load operation. A custom flange can use aluminum alloys with better thermal conductivity (e.g., AL7075) and incorporate cooling fins.
• Sealing and protection requirements: In special environments such as food processing, medical, or underwater robotics, the mounting flange needs to include specific O-ring sealing grooves (e.g., for IP65/IP67 protection). Standard flanges typically do not have these special waterproof and dustproof structures.

In summary, providing a standard adapter flange is insufficient to handle these diverse and demanding operating conditions. A custom flange is a better choice.

Updated on: 28/05/2026