Yubao Transmission Technology operates 35+ CNC lathes and Swiss-type machines covering φ21–350mm outer diameter range with maximum machining length of 1500mm, capable of processing complex multi-step structures. With automated loading/unloading systems and in-process inspection, we achieve high-volume precision manufacturing with outer diameter tolerance ±0.003mm and shoulder face runout ≤0.01mm, meeting demanding accuracy requirements for high-end equipment.
| Parameter | Symbol | Unit | Value/Range | Tolerance | Notes |
|---|---|---|---|---|---|
| Maximum Outer Diameter | Dmax | mm | 21–350 | h6–h9 | Largest step diameter |
| Total Length | L | mm | ≤1500 | ±0.05 | Overall shaft length |
| Minimum Diameter | Dmin | mm | Customized | — | Smallest step diameter |
| Number of Steps | n | — | Customized | — | Typically 2–8 steps |
| Shoulder Height | h | mm | Customized | — | Diameter difference between adjacent steps |
| Straightness | — | mm | 0.01 | ≤ | Full-length straightness |
| Cylindricity (each section) | — | mm | 0.005 | ≤ | Measured per section |
| Radial Runout | TIR | mm | 0.008 | ≤ | Between centers |
| Shoulder Face Runout | — | mm | 0.01 | ≤ | Relative to common axis |
| Parameter | Symbol | Unit | Value/Range | Tolerance | Notes |
|---|---|---|---|---|---|
| Surface Roughness | Ra | μm | 0.2–1.6 | ≤ | Fit sections Ra≤0.4, non-fit Ra≤1.6 |
| Surface Hardness | HRC/HV | — | 55–62 | — | Post-heat treatment |
| Material Grade | — | — | Customized | — | Common: 40Cr, 20CrMnTi, 42CrMo, 16MnCr5 |
| Heat Treatment | — | — | Tempering/Carburizing/Nitriding | — | Determined by operating conditions |
| Center Hole Spec | — | — | 1.0–12.5 | — | Type A/B/C |
| Process | Equipment | Range | Accuracy Achieved |
|---|---|---|---|
| CNC Turning | HEADMAN T55/T65, DOOSAN PUMA245, STAR SB-20J | φ21–350mm | Diameter tolerance ±0.003mm |
| Swiss-Type Machining | CITIZEN A20, Ningjiang CKC1120V | Below φ21mm slender shafts | L/D ratio up to 60:1 |
| Cylindrical Grinding | DW-350-CNC, MB1320E | Length ≤1500mm | Radial runout ≤0.003mm |
| Shoulder Finishing | CNC Lathe/CNC Machining Center | Multi-step compound machining | Face runout ≤0.01mm |
| Heat Treatment | HF Induction/Carburizing/Tempering | Local or through hardening | HRC 58–62 |
| Automated Production | Pinsun + Robot Loading | 7×24 continuous | 3× efficiency improvement |
| Structural Element | Function Description | Machining Key Points |
|---|---|---|
| Bearing Mounting Section | Mounts rolling bearings, withstands radial/axial loads | Tolerance m6/k6, Ra≤0.4μm |
| Gear Mounting Section | Secures gears/pulleys, transmits torque | Tolerance h6/g6, with keyway or spline |
| Sealing Section | Cooperates with oil seal to prevent lubricant leakage | Ra≤0.8μm, moderate hardness |
| Thread Section | For locknuts or connection threads | Accuracy 6H/6g |
| Coupling Section | Connects drive end or load end | Tolerance h6, with keyway |
| Transition Radius | Reduces stress concentration, improves fatigue strength | R0.5–R3, polished finish |
| Application Sector | Specific Use | Structural Features |
|---|---|---|
| Reducers | Reducer output shaft | Bearing section + gear section + seal section, multi-step |
| Servo Motors | Servo motor shaft core | Front bearing + rotor + encoder + rear bearing sections |
| Construction Machinery | Hydraulic pump drive shaft | Spline section + bearing section + flange section, high torque |
| Automotive | Transmission countershaft | Multiple gear freewheel + synchronizer mounting sections |
| Machine Tools | Spindle assembly | Front bearing + tool holder + rear bearing + pulley sections |
