The feed mixer planetary gear hub is the carrier body that locates the planet gears inside the reduction stage of a vertical or horizontal total mixed ration feed mixer gearbox. It carries combined torque from three or four planets, reverses direction during unloading, and runs beside a shaft under continuous bending load from the auger. Casting is chosen because the windowed carrier geometry would be slow and wasteful to cut from solid bar, while the near-net shape keeps material continuity around the heavily loaded windows. CNC machining then finishes the bearing seats, pin bores and sealing faces to the concentricity that decides gear mesh quality and service life.
Specifications
| Parameter | Specification |
|---|---|
| Materials | Ductile iron QT500-7, QT600-3; carbon steel cast grades; alloy steel 42CrMo4 (AISI 4140); high-manganese Hadfield steel where sliding wear dominates |
| Casting process | Investment casting for compact carriers; resin sand casting for large vertical mixer carriers |
| CNC machining | CNC turning, boring, milling and drilling on four-axis or five-axis machining centres; planet pin bores to H7; bearing seats to H7 or H6 where specified |
| Dimensional tolerance | ISO 8062 CT5 to CT7; planet pin bore positional tolerance within 0.03 mm of true position |
| Surface finish | Ra 1.6 um on bearing seats and pin bores; Ra 3.2 um on machined sealing faces; Ra 6.3 to 12.5 um as-cast on windows |
| NDT | Magnetic particle inspection (MT) and liquid penetrant inspection (PT) on all stressed areas; ultrasonic testing (UT) on rim and hub sections; radiographic testing (RT) on critical load paths |
| Heat treatment | Normalising, or quenching and tempering to 28 to 36 HRC; stress relieving before finish machining; optional nitriding of pin bores |
| Surface treatment / coating | Manganese phosphate plus oil, black oxide, or oil-impregnated anti-corrosion film for oil-bath service |
| Typical size range | Outside diameter 120 to 520 mm, mass 3 to 45 kg |
| Documentation | EN 10204 3.1 material certificate, PPAP level 3, FAI report, gear mesh and backlash data on request |
Key features
- Integrally cast windows and webs give continuous material flow around the highest-loaded carrier sections.
- Planet pin bores machined to H7 with positional control that keeps load shared evenly between planets.
- Concentricity between the bearing seat, pilot and pin bore circle held within 0.05 mm TIR.
- Stress relieved before finish machining so the carrier holds its geometry through heat and load cycles.
- Ductile iron option provides the damping that keeps mixer gearboxes quiet under reversing load.
- Optional nitrided or induction-hardened pin bores for extended life in continuous-duty mixer wagons.
Applications
- Vertical and horizontal TMR feed mixer planetary reduction gearboxes
- Self-propelled and trailed mixer wagon final drive hubs
- Agricultural auger drive and reel drive planetary stages
- Manure spreader and feed pusher gearbox carriers
- Industrial planetary gear stages requiring windowed carrier castings
Quality and compliance
Ningbo Ruican produces planetary gear hubs under an IATF 16949 certified quality management system, with process control plans, capability studies on the pin bore circle and full heat-to-part traceability. PPAP and first article inspection (FAI) reports are available, covering dimensional results, material certificates to EN 10204 3.1, hardness and NDT records. Every carrier is verified on a coordinate measuring machine before release, so gear mesh, backlash and bearing preload fall inside specification the first time the gearbox is built.
Frequently asked questions
1. Why is a cast carrier better than one machined from solid bar?
A cast carrier keeps material continuity around the windowed sections, uses far less raw material, and lets us put strength where the load path requires it instead of where bar stock happens to be. The result is a lighter part at lower cost with equal or better fatigue performance.
2. How do you hold planet pin bore position?
We finish machine the pin bores in a single set-up on a CNC machining centre after stress relieving, and we verify position and diameter on a coordinate measuring machine for every production sample to confirm process capability.
3. Can you help us redesign a carrier that is cracking in the field?
Yes. Send a failed sample or the drawing and our engineers will review the section thickness, radii and material, run a finite element check against your duty cycle, and propose a revised casting before new tooling is cut.
4. What surface treatment is used for a carrier running in an oil bath?
Most oil-bath carriers are supplied with manganese phosphate plus oil or a light anti-corrosion film, which protects during storage and assembly and is fully compatible with gearbox oil.
5. Do you supply matched sets of carrier, pins and planet gears?
We supply the machined carrier as the core part and can coordinate the machining of pins and the sourcing or machining of planet gears so the set arrives matched and ready to assemble.
6. What inspection records come with the first shipment?
The first shipment carries the FAI report with full dimensional results, the EN 10204 3.1 material certificate, heat treatment charts, NDT reports and the control plan, organised as a PPAP submission if you require one.
