A useful starting point for
- Compact robot mechanisms that need a smooth projecting output and integrated transmission packaging.
- Custom axes where the housing and motor architecture can be developed together.
Configuration & OEM engineering
Inverted Roller Screw Actuators
Package the transmission around internal roller travel
Inverted roller screw actuators use a different transmission layout from a conventional planetary roller screw. In the inverted principle, the rollers travel within an internally threaded tube and the output shaft can remain smooth. Integration starts with the internal travel envelope and the supported rotating and translating members.
Request the applicable drawing / CAD revisionThis is a configuration review, not a stocked SKU listing. Ratings, documentation availability, sample scope and lead time are confirmed for the reviewed design.
The first design decision
Does the inverted arrangement solve your packaging constraint once bearings, anti-rotation and sealing are included?
Define these boundaries
- An inverted roller screw is not simply a conventional screw with the nut driven instead of the shaft.
- A shorter external rod appearance does not remove the need for internal roller travel, support bearings and end-stop clearance.
Configuration choices and required evidence
Use this matrix to compare candidate configurations. Entries describe decisions to make and evidence to request; they are not unverified product ratings.
| Design input | Options to review | Evidence for the decision |
|---|---|---|
| Kinematic layout | Identify every rotating, translating and fixed member | Section sketch showing the output shaft, threaded tube, rollers and anti-rotation path. |
| Internal envelope | Useful output travel plus internal roller and stop clearance | Travel at both ends, cable routing and assembly/service access. |
| Motor integration | Separate motor or an integrated motor concept | Rotor support, drive connection, bearing reactions and encoder space. |
| Output interface | Smooth shaft, guide, seal and tool attachment | Side loads, moments, surface requirements and environment. |
Agree on prototype acceptance before sampling
- 01
Create a motion map
Show the assembly at both travel extremes and mark the moving members. Confirm that internal clearances and anti-rotation remain valid throughout the stroke.
- 02
Check the support stack
Review how axial force and motor torque enter the bearings and housing. Include assembly tolerances and access to retainers or preload adjustments.
- 03
Test reversal and thermal behavior
Agree on loaded reversing motion, temperature and measurement points. Inspect seals and lubrication after the prototype cycle rather than assuming packaging proves durability.
Define the inspection and release package before fixing the sample acceptance criteria.
A practical engineering handoff
Prepare your inverted roller screw actuators RFQ
Copy or download this editable text checklist, fill in the operating conditions and send it for review. For confidential drawings, agree on an exchange method and confidentiality terms first. The website form accepts text; it does not upload CAD.
Engineering RFQ — Inverted Roller Screw Actuators Source: https://minilinearactuators.com/products/inverted-roller-screw-actuators To: [email protected] Company / contact: Application and project stage: Section sketch with rotating / moving members: Useful stroke and installed length at both limits: Output load, speed and reversal profile: Motor / drive constraints and encoder needs: Bearing, guide, seal and service access envelope: Prototype acceptance and intended production quantities: Required drawings / CAD format and revision: Sample quantity / estimated production quantity: Target milestone: Requirements checklist only. Configuration, documentation availability, acceptance criteria and commercial terms require review.
Email the checklist →
Engineering FAQ
How does an inverted roller screw differ from a rotating-nut screw?
The inverted principle includes rollers moving along an internally threaded tube and a smooth output shaft. Merely choosing to rotate the nut of a conventional screw does not make that transmission an inverted roller screw.
Can the output carry bending loads?
Specify all side loads and moments. The guide, shaft and mounting arrangement must be assessed as a complete structure; a smooth output surface is not evidence of an allowable bending-load rating.
Can it be integrated with a frameless motor?
That is an engineering option to assess with the complete section. Motor support, torque transmission, bearing arrangement, sensing, heat rejection and assembly sequence must be resolved before a design can be released.
Compare related architectures
- Ultra Micro Planetary Roller Screws →
Start a miniature transmission feasibility review with the load path.
- Brushless Roller Screw Servo Actuators →
Review the motor, transmission and thermal envelope as one axis.
- Micro Pen Linear Actuators →
Fit a slender actuator without overlooking mounting and cable space.
- Miniature Screw-driven Actuators family →
Review your operating point and interfaces
Published and reviewed · Mini Linear Actuators engineering content