Electromate Introduces Maxon HEJ 70 High-Efficiency Joint for Mobile Robotics

Electromate Inc., Canada’s exclusive distributor of Maxon precision mechatronic components, announces the release of the HEJ 70 High-Efficiency Joint actuator. This compact, fully integrated robotic joint actuator is engineered to meet the demanding performance needs of mobile and manipulation robots. The HEJ 70‑48‑50 actuator combines a torque-dense motor, planetary gearbox, 14-bit absolute encoder, and EtherCAT control electronics into a sealed, IP67-rated package. It delivers a peak torque of ±50 Nm and a maximum joint speed of 28 rad/s, with efficiencies up to 74% at 12 Nm and 26 rad/s. The actuator's compact design (1.05 kg) and high performance make it suitable for lightweight robotic applications. 

Key Specifications  

Peak Torque: ±50 Nm (future variants may exceed 60 Nm)
Max Joint Speed: 28 rad/s @ 60 V; 22 rad/s @ 48 V
Efficiency: Up to 74% at 12 Nm and 26 rad/s
Ingress Protection: IP67 (sealed against dust and water)
Voltage Range: 30–60 V DC
Control Interface: EtherCAT (daisy-chain), PWM fan control, 1 kHz cycle rate, PDO-mapped gains
Position Sensor: 14-bit absolute encoder, < 0.6° error
Torque Sensing: Current-based, ± 0.8 Nm accuracy
Backdrive Torque: ~0.5 Nm
Output Bearing: Cross-roller bearing 

Performance & Reliability 

Continuous Torque: ±19 Nm at 2 rad/s without extra cooling
Efficiency Peak: ~74% at 12 Nm & 26 rad/s; generator efficiency reaches ~72%
Designed for High Cycle Fatigue: 12 million impacts at 38 Nm, 100k at 50 Nm
Operating Life Examples: Over 56,000 hours at 10 Nm, 22 rad/s 

Use Cases 

The HEJ 70 actuator is ideal for:

Autonomous mobile manipulators and cobots
Lightweight robotic arms and grippers
Quadruped and biped robots
End-effector joints, compact SCARA joints, and wearable robotics 

Integration Highlights 

Ready-to-use with onboard control electronics, torque & position sensing, and active cooling system
Simplified system architecture using EtherCAT daisy-chain; reduces external cabling
Includes simulation models for design verification and sizing