- Client
- Extruder gearbox manufacturer, Ahmedabad (name withheld under NDA)
- Industry
- Gearboxes & Power Transmission
- Service
- Machine & Equipment Design
- Platform
- Solid Edge, AutoCAD
- Client region
- India
- Ratios
- 5 · 6.3 · 7 · 12.5 · 14 : 1 from one housing
- Power
- 90 / 100 / 110 / 125 kW at 1440 rpm
- Gears
- Input pinion 21T × 4.5 M · 2nd pairs 59T/17T and 20T × 5 M · EN353 carburised
The challenge
Single-screw extruder gearboxes carry the full screw thrust back into the output shaft, so the output end is dominated by a tandem thrust bearing stack that has to be shimmed and cooled. The manufacturer's existing 200-frame unit had grown into several incompatible versions, one per customer order, each with its own housing pattern.
The new design had to keep one casting and one pattern while covering ratios from 5:1 to 14:1 and powers from 90 to 125 kW. At the low ratios the second-stage pinion is small and highly loaded; at the high ratios the wheel is large and the bearing spans change. Every combination had to be checked, not just the worst case.
Our approach
The train was fixed as a 21T × 4.5 module input pinion against interchangeable input wheels, and a second-stage pair in 5 module — 59T/17T for 6.3:1, 59T/20T for 5:1 and corresponding sets for 7, 12.5 and 14:1 — all on the same two centre distances so the housing bores never move. Each pair was rated at its own power and speed (for example the 125 kW, 1440 rpm, 5:1 set and the 90 kW, 14:1 set) and the ratings were filed per pair.
The gears are EN353 case-carburised with corner chamfers and burr-removal notes on every drawing, 60 m6 and 65 n5 shaft seats with 18 N9 keyways, and h9 tip diameters so the cutter and the inspector read the same numbers. The output assembly was detailed with its thrust housing and bearing stack so the shop can set the preload with shims on the bench.
The manufacturer works in Solid Edge, so the family was built as a Solid Edge assembly with the ratio variants as alternate assemblies, a Parasolid (x_t) master of the 5:1 build for their own checking, and the 2D drawings produced to their existing AutoCAD title block and numbering (PBH-200-08/04 and so on).
What was delivered
One housing pattern now covers five ratios and four motor powers. The customer holds a drawing set of 12 gear drawings plus the housing, shaft and cover drawings and can quote any combination from stock castings, with a rating sheet already on file for each pair.
- Solid Edge assembly family with ratio variants
- Gear pair ratings for every power / ratio combination
- 12 gear drawings with gear data, material and heat-treatment notes
- Housing, shaft, thrust housing and cover drawings
- Parasolid (x_t) master model
Standards and conventions applied
- ISO 6336 gear rating
- EN353 (16MnCr5 grade) case-carburising specification
- ISO 286 fits (m6, n5, N9, h9) on shafts, keyways and tips
- Manufacturer title block and part numbering
Have a similar requirement? Send the drawings, a sketch or a description — an engineer will scope it and reply with an itemised quote within one business day. Request an engineering quote.
