As mentioned before here, I made a very interesting visit to the companies mentioned above, with some fellow students. A quick report:
When we arrived at Bosch/VDT we were welcomed with coffee and sandwiches (worth a visit alone, excellent stuff !). Mr. Museeu(w), a engineer there, gave us a very intensive presentation about their company and the technology they create. Because we were with a very varied group of people, including students, teachers and engineers from throughout the country, the poor guy had to face very in-depth questions. I learned a LOT from it.
Among which was the following. The conventional CVT has some very interesting characteristics. Among which is the slow throttle response. Apparently it has to be that way, because it is impossible to shift from say 1500rpm to 6000rpm in one jolt. Why ? The driver would be trown everywhere (which most people in the room really didn't mind), but also the inertia of the engine would make it impossible. The way they let it work now, is to put in a little delay after the throttle-input and then let the revs climb about 3-4% before continuing in a sinoide until desired revs. (I can scan some graphs later).
The belts itself consist of various parts.
The double T-shaped parts make sure the transmission handles the vertical forces on the belts and provide rigidity, whilst also being flexible (space between them). They are made of high-strength steel (which exactly he could not tell, company secrets... sigh...).
The steel belts are also made of high-strength steel. They have the function to keep everything together, create the connection and handle the horizontal forces.
He also told something about their competitors, which I never heard about. The LUK chain for example and the Aichi belt. Offcourse the VDT s pushbelt was much better -- insert promotion talk -- It has apparently been tried many times to copy their push belt design, for example by the Chinese (who else), but their specific knowledge and highly efficient production facilities make it still viable to produce in The Netherlands.
All the VDT/CVT pushbelts in the world are manufactured in Tilburg, however nor the pullies, nor the casings and other parts are. Their current aim from Marketing point of view would be to start focusing on little cars again. In the past years they put a lot of research in handling more Nm's. Proof is the Nissan Murano for example with around 400 Nm, which is currently their heaviest. However in their biggest market (Japan), where they expect a 50% (!!) market share in 2010, the smaller cars make up the biggest field.
Then we continued into the plant itself. After a security search for camera's we were let in. We saw how the steel sections were made first.
They come in as narrow rolls of steel (3 cm wide I estimate). They are unwinded and then the shape is blanked out. The next step is to harden and nitrate them, after which they are washed. Following were the remaining steps of removing steel remains (sry dnt know the translation) and a very fast automated sanding process (600 km/h inside the machine !). Afterwards they are washed again and remains are again removed. These remains are removed in giant centrifuges by the way.
The tolerances on these things are bizarre, around 0.2 mu. If you touch a single one of them, it must be trown away.
The we continued to the section where the bands were made. They come in as a roll of 50cm wide sheet metal. They are automatically rolled off, cut and welded to a pipe, around 10 cm diameter. Then they are manually taken into the next machine where they are cut into narrow rings. All the twelve rings vary in shape and size and are not interchangeable. The next step is to stretch them into the correct size and shape. This is done in three phases, until the final size.
The assembly is largely automated and was off-limits for us, because it would interrupt the already highly strained production too much.
During coffee, many visiting cards (including mine) changed hands before we left the site.
We continued to a much smaller company in Eindhoven, Drivetrain Innovations. They specialize in new drive train concepts based on existing designs. For their products just look at the website.
They basically do everything from idea to prototype for the OEM's (Large manufacturers). At the moment they were working on a Toyota Vitz (Japanese Yaris) and a Mitsubishi Colt. They both use a DSpace control unit in the back and all the neccesary technology(system, sensors,hydraulics, everything) in the front. I had a ride in the Vitz and their Zero-inertia CVT really works. We got a very good look at all the technology, with a beer in our hands (!!! w00t !!!). Next month it will be shipped to Japan for the first "official" Toyota test drives.
Basically this are the most important things of what was told. Fire away for questions, I'll try and answer them or forward them to the guys on the visiting cards, I got.
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