OTC DAIHEN AII-V6 / A2-V6 Robot Mechanical Structure & Core Parts Analysis
In the OTC DAIHEN automated welding product line, the AII-V6 (and the co-platform A2-V6) is an extremely classic 6-axis industrial robot with a 6kg payload. Its lower base (J1-J3 axes) uses high-rigidity RV gearboxes, while the upper arm (J4-J6 axes) adopts a compact and lightweight harmonic gearbox and synchronous toothed belt transmission architecture.
After 3 years or 12,000 hours of high-load spatial interpolation movement, the dedicated lubricating grease inside the gearboxes of each axis will dry up and deteriorate, and the motor brakes may also wear out. When performing routine overhauls (such as replacing gearboxes, replenishing grease and releasing pressure, or replacing internal highly flexible cables), please strictly follow the official factory exploded view and the parts list for each axis below. Do not mix different models of motors and grease:
📷 Figure 1: OTC DAIHEN AII-V6 / A2-V6 Industrial Robot Complete Mechanical Exploded View

2. AII-V6 / A2-V6 Core Parts Reference Table by Axis
For the convenience of the workshop equipment department, we have compiled the power units, reduction units, and cable accessories of the J1 to J6 axes into a comprehensive global matrix table. Please carefully cross-reference the circled numbers in Figure 1:
| Axis / Location | Image Ref. | Official Part Number | Standard Part Name | Function & Maintenance Notes |
|---|---|---|---|---|
| J1 Axis (Rotating Base) |
① | W-L02149 | AC Servomotor | Provides main power for horizontal base rotation. |
| ② | L10725G00 | RV Gearbox | High-rigidity heavy-duty base reducer. | |
| ③ | 100-0624 | Lubricating Grease | Liquid anti-friction grease dedicated for RV gearboxes. | |
| J2 Axis (Lower Arm Pitch) |
④ | W-L02150 | AC Servomotor | Provides main power for lower arm forward/backward pitch. |
| ⑤ | L10725F00 | RV Gearbox | Reducer bearing the maximum gravity overturning moment. | |
| ③ | 100-0624 | Lubricating Grease | Liquid anti-friction grease dedicated for RV gearboxes. | |
| J3 Axis (Upper Arm Pitch) |
① | W-L02149 | AC Servomotor | Provides main power for upper arm up/down pitch. |
| ⑥ | L10725E00 | RV Gearbox | Reducer driving the elevation angle of the upper arm. | |
| ③ | 100-0624 | Lubricating Grease | Liquid anti-friction grease dedicated for RV gearboxes. | |
| J4 Axis (Arm Rotation) |
⑦ | W-L02148 | AC Servomotor | Provides main power for arm axial rotation. |
| ⑧ | W-L01948 | Harmonic Gearbox | Compact flexspline harmonic reducer. | |
| ⑨ | 2670-053 | Lubricating Grease | Flexible lubricating grease dedicated for harmonic gearboxes. | |
| ⑩ | 2670-017 | Lubricating Grease | Supplemental grease for gear cavities or bearings. | |
| J5 Axis (Wrist Pitch) |
⑦ | W-L02148 | AC Servomotor | Controls the up/down pitch angle of the welding torch. |
| ⑪ | W-L01949 | Harmonic Gearbox | High-precision harmonic reducer for the wrist. | |
| ⑫ | W-L01945 | Timing Belt | Toothed transmission belt connecting the motor and gearbox. | |
| ⑬ | 2670-015 | Lubricating Grease | Specified lubricating grease. | |
| ⑨ | 2670-053 | Lubricating Grease | Dedicated lubricating grease for harmonic gearboxes. | |
| J6 Axis (Flange Rotation) |
⑦ | W-L02148 | AC Servomotor | Controls the rotation of the welding torch flange. |
| ⑭ | W-L02270 | Harmonic Gearbox | High-precision harmonic reducer for the end flange. | |
| ⑮ | W-L01946 | Timing Belt | End axis toothed transmission belt. | |
| ⑬ | 2670-015 | Lubricating Grease | Specified lubricating grease. | |
| ⑨ | 2670-053 | Lubricating Grease | Dedicated lubricating grease for harmonic gearboxes. | |
| Cables & Accessories (Global) |
— | L10525C00 | Main Cable Assembly (1) | Highly flexible main axis cable routing from the base to the upper arm. |
| — | L10485G00 | Upper Arm Cable Assembly (2) | Dedicated flying lead cable for J5 and J6 axis motors and encoders inside the upper arm. | |
| — | L10460B00 | J5, J6 Axis Assembly | Wrist mechanical housing assembly. | |
| ⑯ | W-L01399 | Absolute Battery | Backup battery pack maintaining the mechanical zero coordinates of the encoders. |
* Note: Items with an “Image Ref.” of “—” in the table represent wiring harness components hidden inside the main body, which cannot be visually indicated in the external skeleton exploded view. Please perform disassembly and replacement according to the original factory manual.
💡 AII-V6 / A2-V6 Robot Mechanical Overhaul & Maintenance Red Card Warnings:
- Fatal Error in Gearbox Grease Replacement (Pressure Release Process): The RV gearboxes on axes J1-J3 and the harmonic gearboxes on axes J4-J6 require completely different types of grease (never mix them). More importantly, when injecting new grease, you must simultaneously open both the inlet and outlet ports, and let each axis of the robot run at low speed for over 20 minutes after injection for sufficient “pressure release”. If the oil plug is sealed without fully exhausting the high-pressure air inside the cavity, the internal air pressure will instantly burst the skeleton oil seal of the servo motor, causing massive grease backflow and burning out the entire AC servo motor.
- Absolute Battery (W-L01399) Power-Off Replacement Tragedy: The encoder battery located inside the main body base maintains the spatial absolute position system of the robot’s 6 axes. It is strictly forbidden to unplug the old battery while the main power to the control cabinet is disconnected! Once unplugged during a power outage, the memory of each axis encoder will be depleted, and the robot will completely lose its mechanical origin coordinates. When replacing the battery, the control system must remain powered on, and the hot-swap replacement must be completed within 15 minutes.
- J5 / J6 Synchronous Transmission Belt Tension Management: The J5 and J6 axes in the wrist section rely on belts (W-L01945 / W-L01946) to transmit power. After 2 years of use, the belts are prone to fatigue and elongation, causing the end welding torch to experience a slight “jitter” during emergency stops. When replacing new belts, do not rely solely on manual pressing feeling; a professional sonic tension meter must be used to adjust them within the Hz frequency range specified in the official maintenance manual. Over-tightening will cause motor bearing fragmentation, while under-tightening will lead to tooth jumping.
🛠️ Get Real-Time Quotes & Tech Support for OTC Robot Motors, Gearboxes & Consumables
The “skeleton and muscles” of an industrial robot determine the ultimate precision of the welding trajectory. Whether you need to purchase original RV / harmonic grease, W-L01399 battery pack dedicated for 3-year/6-year major maintenance, or need to overhaul and replace an abnormal W-L02150 servo motor or highly flexible internal coaxial cable, please provide your part numbers or machine nameplate. Feel free to contact us directly to obtain the latest official standard factory quotes and professional on-site maintenance technical scheduling:


