OTC DAIHEN AII-B4 / A2-B4 Robot Mechanical Structure & Core Parts Analysis
In the OTC DAIHEN automated welding product line, the AII-B4 / A2-B4 is a highly dynamic robot with a 4kg payload, designed for high-speed welding of thin plates in complex spaces. Its lower base (J1-J3 axes) uses high-precision RV gearboxes to withstand frequent high-speed emergency stops, while the upper arm (J4-J6 axes) uses miniature harmonic gearboxes for ultimate lightweight flexibility.
Because the B4 series pursues extremely high cycle speeds, the fatigue cycles of the lubricating grease in the gearboxes, motor brakes, and transmission belts of each axis are relatively shorter. When performing routine overhauls (such as replacing gearbox grease, tensioning belts, 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 grease types or disassemble blindly:
📷 Figure 1: OTC DAIHEN AII-B4 / A2-B4 Industrial Robot Complete Mechanical Exploded View
2. AII-B4 / A2-B4 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 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 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 gravity overturning moment of the lower arm. | |
| 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-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 | 2670-015 | Lubricating Grease | Specified lubricating grease. | |
| ⑨ | 2670-052 | Lubricating Grease | Dedicated lubricating grease for harmonic gearboxes. | |
| J6 Axis (Flange Rotation) |
⑮ | W-L02147 | AC Servomotor | Controls the 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 grease. | |
| ⑪ | 2670-017 | Lubricating Grease | Supplemental grease. | |
| Cables & Accessories (Global) |
— | L10460F00 | Cable Assembly (1) | Main communication axis cable from the rear body to the upper arm. |
| — | L10470F00 | Cable Assembly (2) | J5 and J6 axis motor flying leads inside the upper arm. | |
| — | L10470G00 | Cable Assembly (3) | J5 and J6 axis auxiliary cables inside the upper arm. | |
| — | L10470H00 | Cable Assembly (4) | Dedicated J6 axis cable inside the upper arm. | |
| — | L10470C00 | J5 Axis Unit Assembly | J5 axis mechanical module assembly. | |
| — | L10470B00 | J6 Axis Unit Assembly | J6 axis mechanical module assembly. | |
| — | L10460R00 | Power Cable | High-voltage servo power cable inside J1. | |
| — | L10460S00 | Power Cable | Servo power cable from J2 to the upper arm. | |
| ⑱ | 100-2147 | Battery (Absolute) | Backup lithium battery 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-B4 / A2-B4 High-Speed Robot Overhaul & Maintenance Red Card Warnings:
- Gearbox Grease Replacement (Forced Pressure Release Process): The B4 series robots run at extremely high speeds, generating significant heat inside the gearbox cavities. When injecting new grease (e.g., 100-0624), you must open both the inlet and outlet ports simultaneously, and let each axis of the robot run 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 expanding air during operation will instantly burst the servo motor’s skeleton oil seal, causing massive grease backflow and completely burning out the AC motor coils.
- High-Frequency Start-Stop & J5/J6 Belt Fatigue Broken Teeth: The J5 and J6 axis transmission belts (W-L02051) in the wrist section of the B4 model must withstand long-term, high-frequency, short-distance emergency stops and starts. 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 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 cabinet is disconnected! Once unplugged during a power outage, all encoder origin coordinates will instantly clear to zero. When replacing the
100-2147battery, the system must remain powered on, and the new battery must be plugged in immediately after removing the old one.
🛠️ Get Real-Time Quotes for A2-B4 Robot Motors, Gearboxes & Cables
The “skeleton and muscles” of a high-speed robot determine its long-term trajectory repeatability. Simply provide the required official part numbers (e.g., W-L02149, 100-2147 Battery), and our automated spare parts system will quickly match and output an accurate in-stock quote for you. Whether you need original RV/Harmonic grease for routine maintenance or internal highly flexible cable assemblies for a complete overhaul, feel free to contact us directly: