OTC DAIHEN AII-B4L / A2-B4L Extended-Arm Robot Mechanical Structure & Core Parts Analysis
In the OTC DAIHEN automated welding product line, the AII-B4L (and the co-platform A2-B4L) is a light-payload, extended-arm highly dynamic robot specifically designed for high-speed welding in ultra-large span spaces. Its lower base (J1-J3 axes) utilizes high-precision RV gearboxes to withstand the massive physical overturning moment caused by the extended lever arm, while the upper arm (J4-J6 axes) employs miniature harmonic gearboxes to achieve extreme end-effector flexibility.
Because the B4L series features both “extended arm” and “high speed” characteristics, the frictional heat of the lubricating grease inside the gearboxes and the tensile fatigue of the transmission belts far exceed those of standard models. When performing routine overhauls (such as grease replacement and pressure release, belt tension calibration, 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-B4L / A2-B4L Extended-Arm Industrial Robot Complete Mechanical Exploded View
2. AII-B4L / A2-B4L Core Parts Reference Table by Axis
For the convenience of the workshop equipment department, we have consolidated the power units, reduction units, and cable accessories for axes J1 through J6 from scattered tables into a comprehensive global matrix table. Please carefully cross-reference with 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-L02150 | AC Servomotor | Provides main power for wide-range horizontal base rotation. |
| ② | W-L02116 | RV Gearbox | High-rigidity base reducer. | |
| ③ | 100-0624 | Lubricating Grease | Liquid anti-friction grease dedicated for RV gearboxes. | |
| J2 Axis (Lower Arm Pitch) |
④ | W-L02152 | AC Servomotor | Provides main power for lower arm forward/backward pitch. |
| ⑤ | W-L02117 | RV Gearbox | Reducer bearing the massive gravity overturning moment of the extended arm. | |
| ③ | 100-0624 | Lubricating Grease | Liquid anti-friction grease dedicated for RV gearboxes. | |
| J3 Axis (Upper Arm Pitch) |
① | W-L02150 | AC Servomotor | Provides main power for extended upper arm up/down pitch. |
| ⑥ | L10725G00 | RV Gearbox | Reducer driving the elevation angle of the extended 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-L02034 | Harmonic Gearbox | Compact flexspline harmonic reducer. | |
| ⑨ | 2670-052 | Lubricating Grease | Flexible lubricating grease dedicated for harmonic gearboxes. | |
| ⑩ | 2670-017 | Lubricating Grease | Supplemental grease for gear cavities or bearings. | |
| ⑪ | 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. |
| ⑫ | L10725H00 | Harmonic Gearbox | High-precision harmonic reducer for the wrist. | |
| ⑬ | W-L02051 | Timing Belt | Toothed transmission belt connecting the motor and gearbox. | |
| ⑭ | 2670-017 | Lubricating Grease | Specified lubrication accessory. | |
| ⑨ | 2670-052 | Lubricating Grease | Dedicated lubricating grease for harmonic gearboxes. | |
| J6 Axis (Flange Rotation) |
⑮ | W-L02147 | AC Servomotor | Controls the high-speed rotation of the welding torch flange. |
| ⑯ | W-L02036 | Harmonic Gearbox | High-precision harmonic reducer for the end flange. | |
| ⑭ | 2670-015 | Lubricating Grease | Specified lubricating grease. | |
| ⑰ | 2670-053 | Lubricating Grease | Dedicated lubricating grease for harmonic gearboxes. | |
| ⑩ | 2670-017 | Lubricating Grease | Supplemental anti-friction grease. | |
| ⑪ | 2670-017 | Lubricating Grease | Supplemental anti-friction grease. | |
| Cables & Accessories (Global) |
— | L10525C00 | Cable Assembly (1) | Highly flexible main axis cable from the rear body to the upper arm. |
| — | L10525D00 | Cable Assembly (2) | J5 and J6 axis motor communication flying leads inside the upper arm. | |
| — | L10525E00 | Cable Assembly (3) | J5 and J6 axis auxiliary cables inside the upper arm. | |
| — | L10470H00 | Cable Assembly (4) | Dedicated short J6 axis cable inside the upper arm. | |
| — | L10470C0O | J5 Axis Unit Assembly | J5 axis mechanical module assembly. | |
| — | L10470B0O | J6 Axis Unit Assembly | J6 axis mechanical module assembly. | |
| — | L10485000 | Power Cable | High-voltage servo power cable inside J1. | |
| — | L10485S00 | Power Cable | Main servo power cable from J2 to the front section of the extended arm. | |
| ⑱ | 100-2147 | Battery (Absolute) | Backup lithium 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-B4L / A2-B4L Extended-Arm High-Speed Robot Overhaul & Maintenance Red Card Warnings:
- Extended-Arm Model Gearbox Grease Replacement (Forced Pressure Release to Prevent Oil Burst): The B4L possesses both an extended arm moment and high rotation speeds, generating massive heat inside the gearbox cavities. When injecting new grease (e.g., 100-0624), you must absolutely open both the inlet and outlet ports simultaneously, and let each axis of the robot run continuously at 30% low speed for 20-30 minutes after injection to thoroughly “release pressure”. If the oil plug is sealed without fully exhausting the high-pressure air inside the cavity, the rapidly expanding air during operation will instantly burst the servo motor’s internal skeleton oil seal, causing massive grease backflow and completely burning out the AC servo motor.
- Extended-Arm Front-End High-Frequency Start-Stop & J5/J6 Belt Fatigue: When executing high-speed short-seam jumps, the J5 and J6 axes at the very end of the B4L extended arm must endure severe alternating stress on their transmission belts (W-L02051). If the belt tension is too loose during maintenance, “tooth jumping” is highly likely to occur, causing the welding torch TCP to instantly deviate severely; if the tension is too tight, it will crush the miniature bearings of the motor spindle. When replacing belts, a professional sonic tension meter must be used to accurately adjust them to the Hz frequency baseline specified in the official maintenance manual.
- Absolute Battery (100-2147) Live Hot-Swap Rule: The backup battery located inside the base maintains the spatial absolute position memory of the robot’s 6 axes. Never unplug the old battery while the main power to the control system is disconnected! Once unplugged during a power outage, all encoder origin coordinate parameters will instantly clear to zero. When replacing the
100-2147battery, the control cabinet must remain powered on, and the new battery must be plugged in within 15 minutes after removing the old one.
🛠️ Get Real-Time Quotes for A2-B4L Robot Motors, Gearboxes & Cables
The health of an extended-arm high-speed robot’s “skeleton and muscles” directly determines the trajectory repeatability in space. Simply provide the required official part numbers (e.g., W-L02150 Motor, 100-2147 Battery), and our automated spare parts system will quickly match and output an accurate, ready-to-ship quote for you. Whether you need original RV/Harmonic grease for routine maintenance or internal highly flexible long-axis cable assemblies for a complete overhaul, feel free to contact us directly: