The head pulley hub sits at the discharge end of a bucket elevator and transmits the full drive torque from the shaft into the pulley rim while carrying the belt tension, the belt tracking loads and the weight of the loaded belt. Because the hub must run true at the top of the elevator where misalignment shows up immediately as belt wander and uneven belt wear, concentricity between the bore, the hub face and the rim register is more important than raw strength. We cast the hub blank so the webs and bolt bosses can be shaped to spread load into the rim, then CNC machine bore, keyway, face and register in a single set-up so those features share one true datum.
Specifications
| Item | Specification |
|---|---|
| Part name | Bucket elevator head pulley hub |
| Typical size range | Bore 40–300 mm, hub outside diameter up to 800 mm, 10–260 kg finished weight |
| Casting process | Resin-bonded sand casting; investment casting for small hub bodies with integral locking elements |
| Materials | Ductile iron QT450-10 and 500-7, alloy steel 42CrMo4, high-manganese Hadfield steel for abrasive duty, wear-resistant high-chrome white iron inserts where required |
| Heat treatment | Stress relieving or ferritising anneal for ductile iron hubs; quench and temper for 42CrMo4; water quench solution treatment for Hadfield grades |
| Casting tolerance | ISO 8062 CT6–CT8 according to casting size class |
| Machining | CNC vertical lathe and machining centre: bore, keyway or splined bore, hub face, rim register, bolt circle, taper-lock or keyless locking device seat |
| Machining tolerance | Bore to H7 or to drawing; runout typically within 0.05 mm between bore, face and rim register |
| Surface finish | Ra 1.6–3.2 µm on bore and register seating faces; Ra 6.3 µm on non-functional surfaces |
| Hardness | Ductile iron 160–220 HB; 42CrMo4 quenched and tempered to 260–320 HB; Hadfield steel 187–229 HB work hardening in service |
| Balancing | Static balancing of the machined hub, dynamic balancing of the assembled pulley on request |
| NDT | Ultrasonic testing to EN 12680 severity level 2 or 3 on the hub-to-web transition, magnetic particle or dye penetrant inspection on machined surfaces |
| Documentation | EN 10204 3.1 certificate, hardness report, heat treatment chart, dimensional and runout report, FAI and PPAP submission |
| Production volume | Single prototypes through to annual series programmes |
Key features
- Bore, keyway, hub face and rim register machined in one clamping so concentricity is generated rather than transferred between set-ups.
- Web and boss geometry shaped in the casting to feed load smoothly into the rim and avoid the stress concentration typical of welded plate hubs.
- Ductile iron QT450-10 gives high damping and good machinability for standard elevator duty; 42CrMo4 covers high torque and shrink-fit applications.
- Locking element seats prepared for taper bush, keyless locking device or interference fit to your drawing.
- Bolt circle drilled and tapped to the specified pitch with thread gauges verified on every part.
- Dimensional and runout reports supplied per hub so your assembly line does not need to re-measure.
Applications
- Centrifugal and continuous discharge bucket elevators for grain, feed and fertiliser.
- Cement, clinker and raw meal elevator head shafts.
- Power plant and biomass handling bucket elevators.
- Bulk terminal elevators handling pellets, ore and mineral concentrates.
- Retrofit and spare part programmes for installed elevator fleets.
Quality and compliance
Every hub is produced under the IATF 16949 certified quality system at Ningbo Ruican, which means the casting parameters, heat treatment batch and inspection records for each part are linked by a single traceable part number. First article inspection documents the full bore-to-register relationship with a CMM report, and series shipments are supported by PPAP level 3 submissions. Material conformity is evidenced by EN 10204 3.1 certificates giving ladle analysis and mechanical properties for each heat, while hardness test reports are taken on the actual casting as delivered. NDT reports covering ultrasonic, magnetic particle or penetrant examination of the hub-to-web transition are included whenever the drawing calls for them.
FAQ
Which hub material should I specify for a grain elevator?
Ductile iron QT450-10 covers the great majority of grain and feed elevators because the torque is moderate and the damping is good. Move to 42CrMo4 when shrink-fit torque transmission, higher belt pull or a compact hub section drives the design.
Can you machine the hub for a taper bush or a keyless locking device?
Yes. We prepare the bore and taper to the locking element drawing, check the taper with a dedicated gauge and record the contact pattern on the inspection report before shipment.
How do you control runout between bore and rim register?
Both features are machined in one clamping on a CNC vertical lathe, so they share a single datum. Runout is then verified on the CMM or with a dial indicator set-up, and the measured value is printed on the part report.
Do you supply hubs for existing pulleys where no drawing exists?
We can reverse engineer an existing hub from a sample or a customer dimension sheet, produce a drawing for approval and then manufacture to the approved geometry, including any improvements to the fillet radii.
What surface protection do you apply?
Hubs are shipped with machined surfaces protected by rust preventive oil and, where specified, phosphate coating or primer paint on the non-machined areas. Export packing uses sealed crates with vapour corrosion inhibitor.
CTA
Need a quote for Bucket elevator head pulley hub? Send your drawing to sales@cnsandcasting.com or WhatsApp +86 137 7712 4360 for a fast RFQ response from Ningbo Ruican.
