A spline shaft is not simply a shaft with teeth. The spline geometry, fit relationship and manufacturing process must work together to transfer torque smoothly and maintain reliable assembly performance.
YUBAO manufactures custom spline shafts for OEM applications where accurate torque transmission, repeatable positioning and compact mechanical connections are required. From CNC hobbing, spline shaping and rolling to heat treatment, grinding and inspection, each process is selected around the finished application.
Reference values are used for preliminary screening. Final geometry, fit, material, heat treatment and inspection scope are confirmed after drawing review.
A useful spline does more than add teeth to a shaft. It has to distribute torque, locate the mating component and maintain the right clearance after heat treatment and finishing. The best design matches the load and assembly method without adding unnecessary complexity.
A spline spreads load across several teeth instead of concentrating it at one keyway, supporting compact connections and higher torque capacity when engagement is designed correctly.
Tooth form, engagement length, clearance, runout and datum relationships must work together to achieve stable assembly and repeatable positioning.
Rolling, hobbing, shaping and grinding serve different spline forms and production needs. The drawing, material and annual demand determine the practical route.
Reference ranges for early project screening. Final capability depends on the spline form, mating fit, material, heat treatment and functional datum structure defined in the drawing.
| Feature | Reference Capability | Engineering Relevance |
|---|---|---|
| Size Range | OD Ø21–350 mm · finished length up to 1500 mm | Feasibility depends on spline position, effective engagement length, shaft proportions and machining access. |
| Spline Geometry | Straight-sided and involute · external and selected internal · module 0.5–3.0 · 3–100 teeth | Tooth form, pressure angle, fit and engagement must match the mating component and selected standard. |
| Accuracy & Datums | Grade 7 reference · straightness, runout and spline-to-journal coaxiality reviewed by drawing | Final values depend on shaft length, heat-treatment movement and the functional datum plan. |
| Surface & Treatment | Ground shaft surfaces · finished tooth surfaces · tempering, carburizing, induction hardening and nitriding | Roughness, hardness and case depth are selected around wear, load, noise and service-life requirements. |
| Materials & Process | 20CrMnTi, 40Cr, 16MnCr5 and drawing-defined steels · rolling, hobbing or shaping | The practical route depends on spline type, material, annual volume, access and inspection requirements. |
Open a group only when the drawing needs a deeper review of fit, datums, treatment or inspection.
| Item | Reference Information | Why It Matters |
|---|---|---|
| Spline Standard | GB/T 1144, ISO 14, GB/T 3478, ISO 4156, DIN 5480 or drawing-defined | The standard defines tooth geometry, fit class, mating requirements and inspection method. |
| Pressure Angle | 20°, 30° or 45° where applicable | The pressure angle must match the mating component and selected spline system. |
| Centering Method | Outside diameter, inside diameter or tooth-side centering | The selected method affects assembly fit, runout control and inspection. |
| Effective Spline Length | Drawing-defined · ±0.05 mm reference where applicable | The working engagement length should be separated from the total machined tooth length. |
| Fit & Backlash | Fixed, sliding or project-specific | The required fit influences assembly movement, torque transfer, noise and service behavior. |
| Internal Spline Access | Subject to bore diameter, spline length, tooth form and tooling access | Internal splines require a separate manufacturing and inspection review. |
| Control Item | Reference Capability | Engineering Note |
|---|---|---|
| Straightness | Down to 0.01 mm | The requirement must be tied to shaft length, diameter and the agreed measurement span. |
| Cylindricity | Down to 0.005 mm | Applied only to agreed shaft-body, journal or fit surfaces. |
| Radial Runout | Down to 0.008 mm | The reference centers, datum axis and measured feature must be identified in the drawing. |
| Spline-to-OD Coaxiality | Down to 0.03 mm | Important for centering, rotating stability and repeatable assembly. |
| Surface Finish | Shaft surfaces Ra 0.2–0.8 μm · tooth surfaces down to Ra 1.6 μm | Applied only to functional surfaces where the drawing requires finishing. |
| Materials | 20CrMnTi, 40Cr, 16MnCr5 and drawing-defined steels | Material selection depends on torque, wear, impact load and the intended heat-treatment route. |
| Heat Treatment | Tempering, carburizing, induction hardening or nitriding | Hardness, case depth, distortion allowance and final grinding must be reviewed together. |
| Case Depth & Hardness | Case depth 0.5–1.5 mm reference where applicable · final hardness drawing-defined | Only applicable to compatible materials, tooth geometry and treatment routes. |
| Inspection | Gear measurement, gauges, runout and dimensional inspection | Critical spline and shaft characteristics follow the agreed inspection and production control plan. |
The process is selected around the spline form and the finished shaft—not around one machine. Heat treatment, grinding and inspection are planned around the datums that matter in the assembly.
Rolling is efficient for suitable external splines and repeat volumes. Hobbing provides a flexible route for many external tooth forms, while shaping can support internal splines and special structures. The drawing, material and annual volume determine which method makes sense.
After heat treatment, journals, fits and selected spline surfaces can be ground where the drawing requires it. Inspection focuses on tooth geometry, runout, coaxiality, engagement length and the relationship between the spline and the rest of the shaft.
YUBAO matches the tooth form, engagement, material and fit to the load, speed and assembly method shown in the drawing.
Forklift, hydraulic-pump and mobile-equipment shafts requiring compact torque transfer, durable teeth and reliable engagement.
Input, output and intermediate shafts where centering, runout and repeatable assembly are critical to the finished drive.
Transmission and PTO-style shafts designed around the required module, tooth count, fit, surface hardness and service load.
A spline is not always the best connection. Compare these alternatives before the drawing is released for production.
Yes. YUBAO reviews the spline geometry, mating standard, material, heat treatment, datum relationships, inspection requirements and expected volume before confirming the manufacturing route.
Straight-sided or rectangular splines and involute splines can be reviewed. External splines are common, while selected internal geometries depend on diameter, length, access and tolerance.
The route depends on spline type, material, accuracy and annual volume. Rolling suits selected external forms, hobbing is flexible for many external splines, and shaping can support internal or special structures.
Send the 2D drawing and 3D model where available, together with the spline standard, module, tooth count, pressure angle, fit, engagement length, material, treatment, quantity, annual demand and application requirements.
