Full specification
| Parameter | Value |
|---|---|
| Frame / size | Φ45 × 52 mm |
| Through-bore | Φ4 mm |
| Ratio | 25:1 |
| Rated power | 25 W |
| Rated speed | 120 rpm |
| Rated torque | 2 N·m |
| Peak torque | 6 N·m |
| Weight | 215 g |
| Supply / comms | 48 V · CANopen |
| Backlash | ≤12 arcmin reverse |
| Protection | IP54 · dual absolute encoder |
Source: EYOU (Yiyou Robot) selection manual 2026.08, p. 11 — a few cells reconstructed from the PDF table and marked approximate. Figures verified November 2026 — confirm the exact variant against the datasheet issued with your order.
When this is the right choice
- 120 rpm at the output. A harmonic at 101:1 gives a fraction of that — for a pan axis, a feeder or a small wheel this speed is the whole point.
- 215 g with a driver inside. No external servo drive, no encoder cable to the controller cabinet.
- Φ4 bore lets a small harness or a Bowden cable pass through the axis.
- Cheapest way to add a light axis — a planetary stage is a fraction of a harmonic strain-wave set.
When it is the wrong choice
- Backlash up to 12 arcmin. Never use this where the axis has to hold an absolute position under reversing load — that is what PHA and PHU exist for.
- 6 N·m peak is low. A 25:1 planetary amplifies shock straight into the gear; the peak figure is a limit, not a margin.
- Rated speed 120 rpm is the design point. Run it slower and the 2 N·m rating still holds, but the efficiency and thermal margin both fall.
- No brake variant published. A vertical axis will drop when disabled.
Alternatives at a similar level
- EYOU RP50L — 5 N·m at 410 g — more torque, same family
- EYOU PHA08L-101-C — 1.65 N·m of zero-backlash harmonic at 207 g
- DAMIAO DM-J3507 — Comparable small planetary class, lower cost
Quote this model
Model, quantity and destination is enough to start — we come back with price, availability and the datasheet.
RP40C FAQ
Harmonic or planetary for a small axis?
Planetary if the axis moves fast, is cheap to replace and can tolerate 12 arcmin of backlash. Harmonic if the axis holds position under load or has to be precisely where you commanded it. The mass difference at this size is small; the behaviour difference is not.
Is the driver inside the joint?
Yes — RP and PP are integrated joints: motor, planetary stage, encoder and CANopen drive in one housing, which is why 215 g is even possible.
How long does it take to ship?
Confirmed per order at quotation. Torque figures in this series come from the catalogue table and we re-confirm them with the factory before quoting.
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