Hollow Shaft Motor
Compact & Power Dense
Hollow Shaft Motor
A hollow shaft motor is a type of electrical motor where the centre is open, to ease integration of other components or allow routing of for example cables or tubes. These motors are typically of the frameless type, although it can be also framed, and are used in applications where a compact and power dense motor is required. The compact format and the open space in the centre of the motor, allows for multiple packaging and integration options for the design.
Alva’s SlimTorq™ hollow shaft motors showcase a great OD to ID ratio, with one of the most compact motors on the market. This extremely thin shape is made possible by the FiberPrinting™ manufacturing method, where both the higher copper fill factor and non-skewed windings help out to create a highly power dense and efficient stator. The halbach array rotor then finishes off a motor design which allows for a large inner diameter to be utilized as wanted.
SlimTorq™ Hollow Shaft Motors
Alva’s standard SlimTorq™ hollow shaft motors cover a range of dimensions. For most options on the outer diameter, there are two different alternatives regarding inner diameter. This results in a lightweight “Lite” (L) and a power dense “Max” (M) version, where the lightweight alternative also provides a larger hollow shaft alternative. The smallest motor has an outer diameter of 25 mm, and the largest 160 mm, and no motor is longer than 27 mm in the axial direction. The motors can be configured with different termination directions (radial or axial), different winding configurations and with different types of sensors (temperature or hall-effect).
More information about the standard products can be found in the product catalog or in the product selector, and if help is needed please don’t hesitate to reach out to us.
Custom Hollow Shaft Motors
FiberPrinting™ is a very flexible manufacturing technique, which makes it possible to customize the stator windings to create a custom hollow shaft motor. This is done by changing the winding pattern, length and width of the stator mat. In combination with changing the size and number of magnets, the design of the motor can be adapted for specific requirements, or even optimized for some specific motor characteristic.
If a custom motor is of interest, please contact us for further information.
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The table above shows, in a condensed way, what is possible for the SlimTorq™ hollow shaft motors in terms of specifications. If a customization is required, please contact us to further discuss the details.
Hollow Shaft Motor Applications
Alva’s hollow shaft motors are suitable for many applications. Everywhere where a compact and thin motor can benefit the design, and ease for example integration of other components (like gears), or routing of cables and tubing through the centre, these motors are a great fit. Many applications where this is needed also benefit from saving weight, having high torque density and a high motor constant. Typical applications are:
- Humanoids and other legged robots
- Robot arms and cobots
- Gimbals and other precision optronic applications
- Exoskeletons
- Robotic surgery equipment
These motors take about 16-20 weeks from fixed specifications to first deliveries.
6-8 weeks is normally expected.
Either a NTC temperature sensor, or hall-effect sensors is possible to include in the delivery.
Yes, it is possible to design a system where an Alva hollow shaft motor is coupled with a slip ring.
There are a few different integration methods. Axial clamping or bonding for example, but a full integration manual can be found in the product catalogue.
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