There are various types of CVT (Continuous Variable Transmission), but there are the following types of friction type.
(1) Belt type using V-groove pulley ... There are various belts such as metal belts and chains.
(2) Toroidal type that uses the donut-shaped roller
Currently, the method of (1) is widely used in automobiles. (2) has been used for several car models, but it seems that it has ended.
These types of CVT are not used in the aero engine itself.
However, I knew that the Toroidal CVT of (2) is used for an AC generator (115V, 400Hz) called IDG (Integrated Drive Generator), which is an accessory for the aircraft that is attached to the gearbox.
Also it is called CSD (Constant Speed Drive).
I wanted to know the basic structure and made a simple model.
A. Features of this model (elements required for products vs countermeasures for this model)
Required elements for products ・→・ Countermeasures in this model
① Part accuracy (high accuracy required) ・ → ・ PLA material, FDM 3D printer used
② Bearing (Thrust bearings are often used) ・ → ・ Ball bearings are used instead
③ Special oil (traction) (high friction resistance) ・ → ・ Not used
④ Power Roller shaft rotation method (using hydraulic pressure) ・ → ・ Lever method
⑤ Double toroidal set (for thrust cancellation) ・ → ・ Single set
⑥ Output shaft planetary gear mechanism ・ → ・ Omitted
The speed changing state has been reproduced using the "Air Starter" produced earlier as the power source.
B. Assembly Manual (PDF format, total 15 pages)
The detail assembly manual including "Parts-List", "After printing treatment" and "Assembly procedure" are prepared based on "Standard Skill (Filing, Drilling, Tapping and painting)".
C. Purchase Parts Information;
- Bearings- 6804ZZ(x4), 6807ZZ(x2), HK1210(x1)
- Aluminum Tubes
- Wave Washer WW-40
- Screws, Washer, Nut
M2 x ** -, M3 x **, M4 x **, M6 x ** - See Parts List
D. STL file
Total STL files are 29 items including the tools.
“ws” of last 2 digits of file name means “With Support” special designed.
E. Total Net Print Time: Approx. 83 HR
- (Estimated as case of PLA, 0.4mm Nozzle, 0.2mm Layer Height, 40% infill and No raft and support)
Note: When at actual print, each parameter may be adjusted by your experience.
F. Printing settings
Raft, Support, Layer Height, Infill: Depending on your experience.
My models were printed by "idbox" using with 0.4 nozzle, 1.75 PLA.
Polishing for surfaces of Power-Roller, Disk and Cam is very useful to get smooth movement.
I do hope your success!!