Quick answer: frameless motor or integrated joint module?
Choose a frameless motor when the joint needs custom mechanical integration and your team can own that engineering work. Evaluate an integrated module when its documented package meets your load, space and interface requirements. Compare the complete installed joint, including bearings, feedback, drive, cooling and validation. Neither option has a universal cost, torque-density or development-time advantage.
Updated September 18, 2026. This is an engineering scope comparison; cost and schedule must come from the actual project and supplier quotations.
1. What a frameless motor supplies
A frameless motor is supplied as a stator and rotor for installation into the surrounding machine structure. The complete mechanism must provide appropriate support, feedback, drive electronics and thermal paths. The Kollmorgen frameless motor explanation describes this component boundary.
A frameless motor is not automatically a direct-drive joint. It can be combined with a reducer if the application requires one. Your team can use a compatible commercial servo drive; frameless integration does not necessarily require writing field-oriented-control firmware from scratch.
2. What an integrated joint module supplies
An integrated module combines multiple actuator components into a package. The exact scope varies: confirm the motor, reducer, output bearing, encoder, driver, brake, connectors and software rather than assuming they are all included. Encoder arrangement and protocol support can also differ by model.
Integration work remains at the robot level: mounting, power supply, wiring, controller mapping, heat transfer, fault behavior and load validation. A module's advertised peak torque is not proof that it meets the continuous motion cycle.
Evaluating Integrated Joint Modules for Your Robot?
Compare ZHR-P planetary (5.5–120 Nm) & ZHR-H harmonic series. Direct 3D CAD (.STEP) models and torque spec sheets ready for engineering review.
3. Compare equivalent installed systems
| Decision area | Frameless motor integration | Integrated module evaluation |
|---|---|---|
| Mechanical envelope | Design the joint around the rotor/stator and load path | Check the supplied envelope, mounting pattern and cable clearance |
| Bearing and reducer | Select and validate supporting components | Confirm supplied components and allowable loads |
| Feedback and drive | Choose compatible sensors and drive electronics | Confirm encoder architecture, drive scope and supported control modes |
| Thermal capability | Design and validate the installed heat path | Match the supplier's rating conditions to your mounting and duty cycle |
| Mass and torque density | Count all components required for the working joint | State which accessories are excluded from module mass |
| Maintenance | Plan repair, calibration and replacement procedures | Confirm module replacement, spares and firmware support |
| Project cost | Include development, tooling, assembly and validation | Include purchase price, adapters, integration and application validation |
4. Build a cost model without arbitrary volume thresholds
For either option, estimate total project cost = non-recurring engineering + tooling and validation + quantity × installed unit cost + lifecycle support allowance. Use the same production quantity, requirements and time horizon. Document uncertainty in yield, rework, replacement and supplier availability.
A break-even quantity exists only if one design's recurring savings can recover its extra fixed investment. With positive recurring savings, a simple estimate is extra fixed investment divided by per-unit installed savings. Use project quotations and measured assembly assumptions; “under 500 units” or “over 5,000 units” is not a universal selection rule.
Likewise, a design may take more or less time depending on existing drive software, mechanical expertise, supplier documentation and test equipment. Request a deliverable-based schedule rather than accepting a generic development-time claim.
5. Make the architecture decision in four steps
- Eliminate unsuitable packages: torque-speed, diameter, axial length, cooling, load path and interfaces are hard requirements.
- Define ownership: assign responsibility for mechanical tolerances, feedback, drive integration, calibration and testing.
- Compare remaining work: inspect real drawings, manuals, firmware support and component lists for each candidate.
- Validate a representative assembly: test your motion cycle, temperature, output behavior and fault response before production commitment.
Custom integration can be appropriate when geometry or operating conditions require it. A documented module can be appropriate when it fits the requirements and reduces work your team would otherwise need to complete. Keep both options open until the evidence resolves the trade-off.
6. Review ZHR integration scope by configuration
Review ZHR-H harmonic and ZHR-P planetary models against the same requirement sheet. The public ZHR-H page lists CAN / RS485; ZHR-P interfaces are model-specific, and P60 lists CAN only without native EtherCAT. Do not infer CANopen, CAN FD, a brake or a particular encoder arrangement from the family name.
Frequently asked questions
What is a frameless motor?
A frameless motor is supplied as a rotor and stator for integration into a surrounding mechanism. The complete joint still needs appropriate mechanical support, feedback, drive electronics and thermal design.
Does an integrated module include every component?
No universal package definition applies. Confirm the reducer, bearings, encoder, driver, brake, wiring and software scope for the exact configuration.
Which approach has lower total cost?
Compare equivalent installed systems, including engineering, tooling, purchased components, assembly, validation and support. No universal production-volume threshold determines the cheaper option.
Request an integration-scope comparison
Send torque and speed requirements, motion duty cycle, maximum diameter and length, voltage, protocol, prototype and production quantities, target schedule and the components your team plans to design. Ask which components and technical files are included in the proposed module configuration.
Submit your integration requirementsEngineering RFQ path
Choose the architecture that matches your integration capacity
A frameless motor can require customer-side mechanical, bearing, thermal, and control integration. An integrated joint can reduce that system work. Send your target torque, envelope, annual quantity, development stage, and required interface for a grounded comparison.