Tech Torqs #15: What Are the Main Methods for Mounting a Frameless Motor Stator?

Featuring Angus McWilliam, Senior Commissioning Engineer at Alva Industries.

A frameless motor consists of a rotor and stator without a housing, shaft, or bearings, allowing engineers to integrate the motor directly into their own mechanical design.

In this episode of Tech Torqs, we explore the most common methods for mounting a frameless motor stator.

Adhesive bonding is a widely used solution for securing the stator. As a general guideline, the adhesive bond line should cover approximately 50-75% of the stator lamination height and can be controlled by the housing design. It's also important to consider operating temperatures and the thermal expansion of the materials, as these can affect the integrity of the bond.

Another option is axial clamping, where a clamping ring and bolts mechanically secure the stator. The clamping force must be designed to withstand the motor torque without compromising the assembly.

A press fit between the stator and housing is another common method. However, designers should consider the thermal expansion of both components, as mismatched coefficients can reduce the effectiveness of the fit during operation.

Similarly, a shrink fit can provide secure retention while avoiding the need for pressing. As with press fits, operating temperatures and thermal expansion must be considered, and combining the fit with an adhesive bond line can further improve reliability.

Selecting the appropriate mounting method helps ensure reliable performance and long-term durability in frameless motor applications.

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