Gears & PinionsSpur gears
Heavy-Duty Spur Gear with Internal Spline
Heavy-duty spur gear with an involute internal spline. External teeth transmit high torque; the spline fixes and drives the shaft. Used in heavy reducers and mining or metallurgical drives.
Straight teeth outside, involute spline inside
The outer rim carries coarse-pitch, wide-face straight cylindrical teeth, precision cut and in most cases hardened, so the gear absorbs high torque and repeated shock loads over a long service life.
The bore is an involute internal spline. Fitted to the external spline of the mating shaft, it fixes the gear in the circumferential direction and carries torque; alignment is better than a parallel key joint and a certain axial adjustment stays possible during assembly.
Materials, heat treatment and machining range
Blanks are usually 42CrMo or 20CrMnTi alloy steel forgings. Quench-and-temper or carburizing-and-hardening is selected per drawing so the core stays tough while the flanks reach the required hardness; teeth are then hobbed and ground. For this gear family the shop handles outside diameters up to Ø10 000 mm and modules up to M60, with hardening up to Ø10 000 mm; module, number of teeth, pressure angle and accuracy grade are confirmed against your drawing.
Small radial holes in the hub feed lubricant to the spline fit or to an internal bearing, which limits wear on the mating surfaces; a thickened hub keeps the section stiff enough for high-torque duty.
Inspection, typical use and delivery
These gears are commonly used in heavy industrial reducers, metallurgical mill main drives, mine hoists, large cranes and shield machines, meshing with a pinion to reduce speed and raise output torque.
Tooth pitch, runout, hardness and ultrasonic testing are carried out in-house, and dimensional and profile records can be supplied with the part. Typical lead time for this gear type is within 90 days.
Specifications
- Material grades
- 42CrMo, 20CrMnTi
- Heat treatment
- Quench and temper, or carburizing and hardening
- Tooth flanks
- Hardened and ground
- Bore connection
- Involute internal spline
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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