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Joint actuators and motors
The largest single line on most humanoid and arm BOMs, and the one where a specification mistake is hardest to recover from. Here is what we ask before quoting.
What we source in this category
Integrated joint modules combining motor, reducer, encoder and driver in one housing. Frameless torque motors for teams designing their own joints. Servo motors with matched drives. Quasi-direct-drive units for legged platforms.
We quote against your torque, speed, voltage, communication protocol and envelope. If you give us only a torque figure we will come back and ask for the rest, because a quote against one number is not worth having.
What we need from you
- Continuous torque at your duty cycle, not peak
- Bus voltage and peak current available
- Communication: CAN, CAN FD, EtherCAT, RS485
- Envelope and mounting interface, ideally a STEP file
- Encoder requirement: single or dual, absolute or incremental
- Quantity now, and honest quantity in twelve months
Indicative ranges
Ranges we have seen quoted, not a price list. Real quotes depend on volume, spec and the week you ask. Replace these figures with your own once you have run orders.
| Type | Continuous torque | Typical MOQ | Sample lead time | Production lead time |
|---|---|---|---|---|
| Compact joint module | 5–30 Nm | 1–5 | 1–2 weeks | 4–6 weeks |
| Mid joint module | 30–120 Nm | 1–10 | 2–3 weeks | 5–8 weeks |
| High torque hip / knee | 120–400 Nm | 2–10 | 3–5 weeks | 8–12 weeks |
| Frameless torque motor | varies by stack | 5–20 | 1–3 weeks | 4–8 weeks |
The mistake we see most often
A team specifies against the peak torque figure on the datasheet, builds the robot, and the actuator overheats after twenty minutes of walking. Peak is usually quoted for a few seconds into a cold motor. Continuous is the number your thermal design has to live with, and on many Chinese datasheets it is either absent or quoted without stating ambient temperature and heatsinking conditions.
We ask every supplier for the test conditions behind both numbers in writing before we pass a quote to you. When a supplier will not provide them, that is itself the answer, and we tell you.
Send one line and see what comes back.
You do not need a finished BOM to start. Send the single part that is currently blocking you and we will quote it. It costs you an email and tells you more about us than this page can.