ShaftsTransmission shafts
Double-Ended Involute Spline Heavy-Duty Transmission Shaft
Heavy-duty transmission shaft with precision involute external splines at both ends, a stepped enlarged center body for bearing support, and hardened spline surfaces for high-torque transfer.
Machining capability
The shaft is machined from forged alloy steel blanks in grades such as 42CrMo and 40Cr. Shaft machining covers lengths up to 10,000 mm including clamping, diameters up to Ø1,500 mm, and single-piece weights up to 8 t. Journal tolerances to h6/IT7, surface roughness to Ra 0.8, and radial runout of ≤0.02 mm are achievable.
Quenching and tempering plus high-frequency hardening can be applied, with a maximum hardening length of 10,000 mm. Keyways, splines, threads, and end-face flange holes are all within the machining scope.
Structure and operating conditions
The part uses external involute splines at both ends to engage internal spline components at the power input and load output. Compared with a plain key, the spline distributes circumferential load more evenly, carries higher torque, and permits some axial adjustment during assembly.
The stepped, enlarged center body includes bearing shoulders for mounting heavy-duty bearings, spacers, and locknuts. This arrangement provides radial support and axial location while increasing bending stiffness for high torque and alternating impact loads. Common applications include hardened gear reducers, planetary gearboxes, construction machinery, rolling mills, and mine hoists.
Quality control and customization
Dimensions, form and position tolerances, spline profile, runout, and hardness are checked against the drawing. Material certificates and inspection reports can be supplied with the batch.
Spline module, number of teeth, pressure angle, accuracy grade, and surface hardness are confirmed from drawings or measured samples. Overall length, journal diameters, center bore, and end-face threaded holes can be customized to the mating assembly.
Specifications
- Material
- 42CrMo / 40Cr
- Blank
- Forged alloy steel blank
- Heat treatment
- Quenching and tempering; spline surface hardening
- Spline type
- External involute spline at both ends
Common questions
- Can you machine this part to my drawing?
- Yes. Every part is quoted from the drawing. Send a PDF, DWG, DXF, STEP or IGES file with the material, quantity and any inspection requirements, and we reply within one working day.
- How are the material and heat treatment decided?
- They follow your drawing. The specification table shows the range normally used for this part type; the final material and heat treatment are confirmed with the quotation.
- What lead time and inspection come with the part?
- Lead time is set in the quotation and depends on material, size, quantity and inspection scope. Material verification, in-process checks and final inspection records are archived with the part, and any extra certification is agreed before production.
- How is the part packed for export?
- Export parts are rust-proofed and packed for the transport method and destination confirmed in the quotation, with lifting points and markings agreed before dispatch.
Every part is quoted from the drawing itself, not from a size band. Send it over and we answer with the process, the lead time and the tolerance we can hold.
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