OTC DAIHEN FD-B4 Robot Mechanical Structure & Core Parts Analysis
In the OTC DAIHEN automated welding product line, the FD-B4 is an extremely classic 4kg payload through-arm (built-in cable) industrial arc welding robot. To avoid interference between external welding torch cables and workpieces, the B4 model ingeniously routes the coaxial power cable through the interior of the upper arm and wrist (J5/J6 axes). Its base (J1-J3 axes) utilizes high-precision RV gearboxes, while the wrist (J4-J6 axes) integrates hollow-design harmonic gearboxes and crossed roller bearings.
Due to the compact design of the through-arm routing, the lubricating grease space inside the gearboxes of each axis is more precise, requiring higher heat dissipation. When performing routine robot overhauls (such as replacing gearbox grease, tensioning belts, or extracting/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 FD-B4 Through-Arm Industrial Robot Complete Mechanical Exploded View
2. FD-B4 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 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-L02662 | AC Servomotor | Provides main power for wide-range horizontal base rotation. |
| ② | L11130X00 | RV Gearbox | High-rigidity base main reducer. | |
| ③ | 100-0624 | Lubricating Grease | Liquid anti-friction grease dedicated for RV gearboxes. | |
| J2 Axis (Lower Arm Pitch) | ④ | W-L02641 | AC Servomotor | Provides main power for lower arm forward/backward pitch. |
| ⑤ | L11130Y00 | RV Gearbox | Reducer bearing the main 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-L02662 | AC Servomotor | Provides main power for upper arm up/down pitch. |
| ⑥ | L11130Z00 | 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 | Hollow through-cable harmonic reducer. | |
| ⑨ | W-L02555 | Crossed Roller Bearing | Precision rotary bearing carrying multi-dimensional loads. | |
| ⑩ | 2670-053 | Lubricating Grease | Flexible lubricating grease dedicated for harmonic gearboxes. | |
| ⑪ | 100-1491 | Lubricating Grease | Supplemental grease for cross bearing cavity. | |
| ⑫ | 100-1491 | Lubricating Grease | Dedicated anti-friction grease for local contact surfaces. | |
| J5 Axis (Wrist Pitch) | ⑦ | W-L02148 | AC Servomotor | Controls the up/down pitch angle of the welding torch. |
| ⑬ | W-L01949 | Harmonic Gearbox | High-precision harmonic reducer for the wrist. | |
| ⑭ | W-L01945 | Timing Belt | Toothed transmission synchronous belt connecting motor and gearbox. | |
| ⑮ | 100-1516 | Sealant | Original factory anaerobic sealant for leakage prevention. | |
| ⑩ | 2670-053 | Lubricating Grease | Dedicated lubricating grease for harmonic gearboxes. | |
| J6 Axis (Flange Rotation) | ⑯ | W-L02147 | AC Servomotor | Controls the rotation of the welding torch end flange. |
| ⑰ | W-L02036 | Harmonic Gearbox | Zero-backlash hollow harmonic drive for end flange. | |
| ⑱ | W-L02556 | Crossed Roller Bearing | Heavy-load crossed roller bearing for end flange. | |
| ⑮ | 100-1516 | Sealant | Anti-oil leakage sealant for end cover. | |
| ⑲ | 2670-053 | Lubricating Grease | Dedicated anti-friction grease for end high-flexspline friction pair. | |
| ⑪ | 2670-017 | Lubricating Grease | Supplemental grease for gear cavities or bearings. | |
| ⑫ | 100-1491 | Lubricating Grease | Dedicated anti-friction grease for local contact surfaces. | |
| Cables & Accessories (Global) | — | L11130F00 | Cable Assembly (1) | From the rear of the rack to the upper arm. |
| — | L10470F00 | Cable Assembly (2) | For J5 and J6 axes inside the upper arm. | |
| — | L10470G00 | Cable Assembly (3) | For J5 and J6 axes inside the upper arm. | |
| — | L10470H00 | Cable Assembly (4) | For J6 axis inside the upper arm. | |
| — | L10485S00 | J5 Axis Unit | J5 axis mechanical module assembly. | |
| — | L11140B00 | J6 Axis Unit | J6 axis mechanical module assembly. | |
| ⑳ | W-L01399C | 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.
💡 FD-B4 Through-Arm Robot Overhaul & Maintenance Red Card Warnings:
- Gearbox Grease Replacement (Forced Pressure Release to Prevent Oil Burst): When injecting new grease (e.g., 100-0624) into the RV gearboxes of axes J1-J3, 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 forcibly 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 coils.
- Extracting/Replacing Internal Coaxial Cables in Hollow Wrist J5/J6 Axes: The FD-B4 is a through-arm robot; the welding torch coaxial cable passes through the hollow flanges of J4, J5, and J6. Due to repeated bending over the years, the internal highly flexible cables (including wire feed and gas tubes) are prone to fatigue and damage, leading to gas leaks or wire feeding jams. When replacing this coaxial cable package, avoid violent pulling that could break the internal servo feedback flying leads (
L10460G00). Concurrently, check the tension of the J5 axis timing belt (W-L01945), which must be adjusted using a sonic tension meter to the frequency specified by the original factory. - Absolute Battery (W-L01399C) 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 connector while the main power to the control cabinet is disconnected! Once unplugged during a power outage, all encoder origin coordinate parameters will instantly clear to zero. When replacing the W-L01399C battery, the control system must remain powered on, and the new battery must be plugged in immediately after removing the old one.
🛠️ Get Real-Time Quotes for FD-B4 Robot Motors, Gearboxes & Cables
The health of an industrial robot’s “skeleton and muscles” directly determines the trajectory repeatability in space. Simply provide the required official part numbers (e.g., W-L02662 Motor, L11130X00 Gearbox, W-L01399C 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 through-cavity cable assemblies for a complete overhaul, feel free to contact us directly: