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Challenge
Light weight and low cost draws attention in the world.
Implemented a skilled technology "Stamping from 5 directions"
There is a technology which draws the attention of world carmakers..
That is the transmission shaft developed by Kubota Iron Works Co., Ltd., which engages in manufacturing automotive components. Kubota implemented the first one-shot press forming from 5 directions in the world, and succeeded in weight reduction and cost reduction by simultaneous forming of the external and the internal hollow structure.
Various industries such as aircraft, shipping, and agricultural machines have shown interests in the new method generated by skilled die technology.
A man looking at a shaft curiously started to talk with an engineer.
" How did you make it?  Please show me the dies which manufactured this shaft."
At an automotive component manufacturer's technical exhibition held in Nagoya last October, these kinds of questions were repeatedly asked at the booth of Kubota Iron works Co., Ltd. The exhibited product was a transmission shaft sectioned to show the internal hollow structure, which is expected to put to practical use shortly.


Already decided to supply.

The transmission shaft is an axis binding several gears and its standard size is approx. 12cm maximum in diameter, and approx. 60cm in length.
The weight of major manufacturer's existing shafts is approx. 6 kg.
Kubota's shaft is approx. 4 kg, which is lighter by more than 30%.
Total number of inquiries has reached about 10 companies.
Mr. Shigeaki Yamanaka is surprised at the market responses being beyond expectations, and he commented that until now, we have visited customers for the sales of our products, however, now customers visit us.
Conventionally, for making a hollow shaft, the external is pressed first, and then the internal is drilled by a separate machine. In order to form it with one machine at one time, the press from 5 directions is required. No one until now has implemented the one-shot press from 5 directions although it is conceptually conceivable.
In which order and pressure will 5 dies be pressed for the materials?
The person who developed the complicated die movement was a veteran engineer in his seventies and he is called "Human simulator".
Mr. Yamanaka, Director looks back that a veteran engineer's long experience for dies created the idea of the complicated die movement.(although the detailed process is confidential.)

Challenge for survival

Kubota's main product is steel water pumps that cool the engine.
However, in the 1990's, Kubota anticipated the risk that the cost of machining requiring a lot of difficult processes for automation would not be competitive against those of China or South Asian countries.
As a survival measure that Kubota's original die technology can be utilized, Kubota focused attention on cold forging which forms metals by high pressure in normal temperature. Cold forging is the first field for Kubota. In 2002, Kubota established a Research association of 11 automotive component manufacturers having business relations in Hiroshima and researched the basic technology.
Cold forging needs complicated processes to secure high accuracy and it becomes more difficult when the press directions are increased.
Kubota focused on weigh reduction. Carmakers are in fierce competition for fuel consumption improvement and exhaust gas reduction under the circumstances of fuel price increase or eco-consciousness enhancement. If the vehicle weight is reduced, fuel consumption is improved, and exhaust gas is also reduced. Mr. Yamanaka was confident that weight reduction of metal parts would expand the uses.
The press from 5 directions enabled one process forming in 18 seconds, with the internal hollow forming within one process. Furthermore, as the largest hollow can be formed, the weight is reduced drastically.
For Kubota's shaft, aircraft related industry's engineers and shipping & agricultural machine makers also indicate interests. Kubota is going to expand the application to other components than automotive components in the future.
Kubota has found new possibilities of metal shafts by utilizing metal forming experience of more than half-century.

 
 
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