---
title: "Mabuchi Motor IA-B4BZA / IB-B4BZA hollow frameless motor (500 W) specs"
description: "Frameless + Driver actuator from Mabuchi Motor (Japan). Peak torque 2.1 Nm, rated 0.9 Nm, weight 360 g, torque density 5.8 Nm/kg, price quote only."
canonical: https://actuatorlist.com/actuators/mabuchi-ia-ib-b4bza
last-updated: 2026-11-11T13:40:47.000Z
---
# IA-B4BZA / IB-B4BZA hollow frameless motor (500 W) by Mabuchi Motor

> Frameless + Driver actuator from Mabuchi Motor (Japan). Peak torque 2.1 Nm, rated 0.9 Nm, weight 360 g, torque density 5.8 Nm/kg, price quote only.

## Specifications

| Spec | Value |
| --- | --- |
| Category | Frameless + Driver |
| Peak torque | 2.1 Nm |
| Rated torque | 0.9 Nm |
| Max speed | n/a |
| Gear ratio | 1:1 |
| Weight | 360 g |
| Torque density | 5.8 Nm/kg |
| Price | quote only |
| Price per Nm | n/a |
| Backdrivable | yes |
| Backlash | n/a |
| Voltage | 15-55 V |
| Peak current | n/a |
| Communication | n/a |
| Control modes | n/a |
| Encoder | None (stator and rotor kit; add your own sensor) |
| Integrated driver | no |
| Availability | in production |
| Data status | Unverified catalog: confirm sources |

## Size a joint

- [Motor torque calculator](/tools/motor-torque-calculator?solve=power&t=0.9): **0.9 N·m** rated; add a speed for its shaft power.
- [Robot arm torque calculator](/tools/robot-arm-torque-calculator?L=0.4,0.35,0.12&m=1.2,0.8,0.3&a=0.36,0.5,0&p=2): **31.4 N·m** at the shoulder with its 360 g at the elbow of a 2 kg-payload arm.

## Use cases

- cobot joint
- robot arm

## Notes

Motor. Stator (IA) and rotor (IB) set from Mabuchi's IA/IB hollow frameless line, which went on sale in 2022 for collaborative robot joints. Stator outer diameter 75 mm and rotor bore 35 mm, so cables can run through the joint. Mabuchi lists rated output 500 W at 48 V, rated torque 0.9 N.m at 5,300 r/min, and an instantaneous maximum of 2.1 N.m for up to 5 seconds, which is recorded as peak torque. Mass 0.36 kg. Usable supply range 15 to 55 V. Mabuchi notes that rated figures depend on how well the housing sheds heat. No-load speed is not published, so max speed is left null. Needs an external FOC drive and position sensor. Figures were read from search results of Mabuchi's product pages and manual; the pages themselves were not opened, so the row is unverified. power\_w is left null: the rated output is mechanical shaft power and the catalog field is continuous electrical input power, which Mabuchi does not publish.

## Sources

- [https://solution.mabuchi-motor.com/products/iaib\_series/iaib\_b4bza](https://solution.mabuchi-motor.com/products/iaib_series/iaib_b4bza)
- [https://www.mabuchi-motor.com/product/download/pdf/IAIB\_series.pdf](https://www.mabuchi-motor.com/product/download/pdf/IAIB_series.pdf)
- [https://solution.mabuchi-motor.com/en/products/iaib\_series](https://solution.mabuchi-motor.com/en/products/iaib_series)
- [https://www.nikkan.co.jp/releases/view/137521](https://www.nikkan.co.jp/releases/view/137521)

## Similar Frameless + Driver actuators

- [TQ-RoboDrive ILM85x26 (TQ-Systems (RoboDrive))](https://actuatorlist.com/actuators/tq-robodrive-ilm85x26): 14 Nm/kg
- [EC frameless 90 flat (260 W) (maxon)](https://actuatorlist.com/actuators/maxon-ec-frameless-90-flat-260w): 12 Nm/kg
- [RI60 KV120 (CubeMars (T-Motor))](https://actuatorlist.com/actuators/cubemars-ri60-kv120): 10.5 Nm/kg
- [RI80 V2.0 KV75 (CubeMars (T-Motor))](https://actuatorlist.com/actuators/cubemars-ri80-v2-kv75): 10 Nm/kg
- [R60 KV115 (CubeMars (T-Motor))](https://actuatorlist.com/actuators/cubemars-r60-kv115): 9.3 Nm/kg

## Machine-readable

- JSON: https://actuatorlist.com/api/v1/actuators/mabuchi-ia-ib-b4bza
- Catalog index for agents: https://actuatorlist.com/llms.txt