Frameless torque motor
CubeMars RO Series frameless torque motor
Frameless outrunner torque motors from the RO40 Lite (0.6 Nm peak) to the 113.5 mm RO100 (12 Nm peak, series maximum).
Need this part, a replacement or a complete package? Our experienced UK engineering team helps you select, source and obtain the right products, with pricing, delivery coordination and after-sales support.
Pricing and availability
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Need CubeMars parts, a replacement or a suitable alternative? Send us a part number, or tell us what the machine needs to do. Our UK engineers will come back with the right product, pricing, lead time and delivery, whether that is the original part, a checked alternative or a complete axis.
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Select every part you need and answer the questions an applications engineer would ask. Our engineers use your specification to come back with the right products, pricing and lead times. You see your summary before we ask for any details.
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- 1Products
- 2Performance
- 3Environment
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- 5Your spec
What are you specifying?
Select everything you need. A motor, drive and gearbox can be specified together as one axis.
Key specifications
| Outer diameter (max) | 113.5 mm |
|---|---|
| Peak torque (max) | 12 Nm |
| Sizes | RO40 Lite, RO50 Lite, RO60, RO80, RO100 |
Summarised in our own words from Nanchang Kude Intelligent Technology Co., Ltd. (wholly owned subsidiary of Nanchang Sanrui Intelligent Technology Co., Ltd.)'s published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1
Specify Motion is not affiliated with Nanchang Kude Intelligent Technology Co., Ltd. (wholly owned subsidiary of Nanchang Sanrui Intelligent Technology Co., Ltd.). CubeMars and RO Series are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
CubeMars RO Series replacement and alternative options
Use these supply-network options as a starting point for an engineering check. We can also help source the original CubeMars part. Published series figures do not establish an exact-model or drop-in replacement: confirm ratings, fit, interfaces and approvals for your application.
High-voltage (600 VDC) frameless torque motor kits from 110 to 360 mm with large through-bores and integrated Hall sensors; the high-torque end of the Akribis frameless range.
| Published maximum | RO Series | ADR-P |
|---|---|---|
| Continuous torque | — | 365 Nm |
| Peak torque | 12 Nm | 985.5 Nm meets or exceeds |
Ironless (coreless) housed direct drive motors with zero cogging and low velocity ripple, for very smooth low-speed rotation.
| Published maximum | RO Series | ACD |
|---|---|---|
| Continuous torque | — | 9.22 Nm |
| Peak torque | 12 Nm | 32.25 Nm meets or exceeds |
| Speed | — | 1,200 rpm |
Flat, low-profile ironless direct drive motors with large centre holes, zero cogging and high-resolution optical encoders.
| Published maximum | RO Series | ACW |
|---|---|---|
| Continuous torque | — | 7.4 Nm |
| Peak torque | 12 Nm | 35.9 Nm meets or exceeds |
| Speed | — | 400 rpm |
Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
Typical applications
What a frameless torque motor is
A frameless torque motor is a permanent-magnet brushless motor supplied as two parts, a rotor and a stator, with no housing, bearings or shaft. The machine builder mounts the rotor directly on the driven shaft and the stator in the machine structure, so the motor becomes part of the mechanism. Many have large through-holes and high pole counts, giving high torque at low speed with no gearbox. They need separate feedback, typically an encoder, and a servo drive.
When engineers choose a frameless torque motor
Choose a frameless motor when you want direct drive in a compact, integrated design, such as robot joints, gimbals, rotary tables and medical devices. Removing the gearbox eliminates backlash and improves stiffness and smoothness. The trade-offs are integration work and size: the builder supplies bearings, alignment, cooling and feedback, and torque per volume is lower than a geared solution. For off-the-shelf installation, a housed direct-drive motor may be simpler.
How to specify the CubeMars RO Series
Send these with your enquiry and an engineer can confirm the right RO Series variant or an equivalent:
- Continuous and peak torque (Nm)
- Speed (rpm)
- Outer diameter, bore and stack length (mm)
- Bus voltage and current (V, A)
- Thermal mounting and cooling
- Feedback type and resolution
- Air gap and concentricity tolerance (mm)
Common mistakes to avoid
- Leaving air gap and concentricity tolerances undefined
- Ignoring heat conduction from the stator into the housing
- Using an encoder with too low resolution for direct drive
- Forgetting rotor magnet attraction during assembly
CubeMars RO Series: frequently asked questions
Can you help replace CubeMars RO Series or source the original?
Send the full model code, quantity and required date. Our engineers can check original-part availability and assess suitable alternatives, including supply-network options where appropriate. We confirm compatibility and any changes needed before recommending a replacement.
What is the CubeMars RO Series?
Frameless outrunner torque motors from the RO40 Lite (0.6 Nm peak) to the 113.5 mm RO100 (12 Nm peak, series maximum). Published series figures include outer diameter 113.5 mm, peak torque 12 Nm. It is made by Nanchang Kude Intelligent Technology Co., Ltd. (wholly owned subsidiary of Nanchang Sanrui Intelligent Technology Co., Ltd.); Specify Motion can help source it or propose an equivalent.
Who makes the CubeMars RO Series?
The CubeMars RO Series is made by CubeMars (Nanchang Kude Intelligent Technology Co., Ltd. (wholly owned subsidiary of Nanchang Sanrui Intelligent Technology Co., Ltd.)) and is listed here for engineers comparing options. Specify Motion is not affiliated with Nanchang Kude Intelligent Technology Co., Ltd. (wholly owned subsidiary of Nanchang Sanrui Intelligent Technology Co., Ltd.); brand names are used only to identify the product.
What is the outer diameter of the CubeMars RO Series?
The published series maximum outer diameter is 113.5 mm. Individual models and sizes in the RO Series range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
Is there an alternative to the CubeMars RO Series?
We can assess suitable replacement options. On published figures, Akribis Systems ADR-P and Akribis Systems ACD are options to assess from our supply network. An engineer confirms the fit against your application before recommending anything.
What is the difference between a frameless and a housed torque motor?
A frameless motor is only a rotor and stator; the machine provides bearings, shaft, housing and feedback. A housed direct-drive motor adds bearings, housing and encoder in a ready-to-install unit. Frameless suits compact, integrated designs where the machine already has stiff bearings; housed suits faster installation and simpler alignment.
Why use a frameless motor instead of a gearbox?
Direct drive removes backlash, wear and compliance in the gear train, giving smoother motion and stiffer control. It also allows a large hollow shaft for cabling. The trade-off is that torque must come from the motor alone, so it is larger for a given torque.
Further reading: How to select a frameless torque motor · Frameless motor sizing robot joints · Frameless and torque motors
Other frameless torque motor series
Engineer support
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Tell us how you use the CubeMars RO Series: the load, speed, duty and environment. Our engineers will confirm whether it is still the right part, find it for you, or propose an alternative that fits better.
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Prefer to configure it? Use the spec builder.
How it works
From enquiry to delivery
Send a part number or describe the application. Our engineers take it from there: the right product, a clear quotation, and delivery and support arranged.
- 01Tell us what you needSend a part number, or configure the application, quantities and timing.
- 02An engineer reviews itWe check the specification and find the original part, a checked equivalent or a complete axis.
- 03Receive your quotationProducts, pricing, lead time and compatibility notes in one reply.
- 04Order and deliveryWhen you are happy, the order is placed and delivery and after-sales support are arranged.