1. How to save 60% on your Gearwheel Requirements

2. Background on DePe Gear
DePe Gear Company Ltd. Established in 1987 located in Stoke on Trent. England
BS EN ISO 9001:2008
Facilities include some of the most modern gear equipment in Europe. Operating 24hrs per day
Gears from 50mm to 2500mm diameter
Wide spread of customers and industries

3. Main Industries Serviced
Railways
Bulk Handling
Quarrying and Mining
Aerospace
Nuclear
Wind Turbine
Prototype and Development
Pump Gears
Power Transmission

4. How to save 60% on your Gearwheel Requirements

5. Case Study Piccadilly Line Life Extension

6. The 10 year life extension programme included:
replacing all the 17 tooth pinions
replacing /reworking the 75 tooth gearwheels.
Approximately 1300 of each over 4 years

7. Target
If 75% of the gearwheels can be reworked then the saving across the gearwheel project would be
60%

8. Stage 1
Engineers from DePe Gear and London Underground had to establish the acceptance criteria for the reworked gearwheel to ensure the gearwheel would last another 10 years

9. Bore size and condition. After regrinding the teeth
Stage 1
Parameters covered included:
General condition
Bore size and condition.
After regrinding the teeth
Case depth
Span size
Tooth flank hardness

10. Stage 2 Destructive Testing

11. 2 lots of 3 random gears were selected and tested for case depth and metrology. 6 In total

12. Sample of the cross section showing good, continuous and consistent case hardening

13. RESULTS WERE ACCEPTABLE
Stage 3
Trials
3 more gears were selected and processed. The resulting gearwheels were again cut up to measure the case depth etc
RESULTS WERE ACCEPTABLE

14. Stage 4 Confirm costs. Begin work to convert 1300 off

15. To a product that can be refitted and will run for 10 years

16. Process 1 Thorough clean, de-grease and wash off all foreign material

17. Process 2
Set up in the lathe and check for concentricity and polish the bores to remove any minor corrosion or damage .

18. Process 3
Load onto the CNC Gear Grinder and regrind the teeth ensuring that the minimum material is removed but the gear is left with no pitting.

19. Process 4 Check and record the span size and surface hardness.

20. Process 5 Gear graph 1 in 10. To measure the lead, profile and pitch.

21.
Profile, Lead, Pitch and Runout Graphs

22. Process 6 MPI each gearwheel.

23. Process 7 Apply a protective coat and return to London Underground.

24. Progress so far
Over 1000 have now been refurbished and the success rate is currently running at 72%

25. Conclusion.
If you have a major refurbishment project you could save 60% on replacing your gearwheels.