Chapter 553

Hearing Professor Zhao's words, Tong Xia's eyes were also bright. Looking at the black ball in the teacher's hand, she seemed to see something very precious. But thinking about the teacher's body, her expectant eyes were more worried.

It seems that he is aware of the entanglement of the students around him. Professor Zhao coughs excitedly, then waves his hand to indicate that he is OK, and then hands the ball to Tong Xia: "look, this is the silicon nitride bearing I told you about before. I saw it when I visited Europe in the early 1980s. It should be right. Take a good look, it's very useful ……”

At this moment, Professor Zhao is just like a child who has picked up new things. He is both excited and cheerful, and his words become extremely light.

Soon I explained the situation of silicon nitride bearing.

This also starts with the core technology of the helicopter.

Different from fixed aircraft, the core technology of helicopter is divided into several parts, the most important of which is the power system and transmission system.

Power system naturally refers to high-performance turboshaft engine, while transmission system is the part connecting power system and propeller.

Among them, there are many parts, but no matter which part is inseparable from the support and connection of the bearing, so that the transmission system can work better.

Because of this, the bearing has become one of the most important mechanical parts of the helicopter.

So the bearing performance has a great impact on the helicopter, and even in a sense, it can influence the life and death of a helicopter.

How to judge the performance of a helicopter bearing?

The aviation industry has long had a definition standard for this, that is, in the case of no lubricating oil injection, the helicopter bearing works normally for 30 minutes without damage when the turboshaft engine is running at high speed.

Don't underestimate this condition. The general bearing will not be damaged for 30 minutes, but it is estimated that the roller in it will be broken due to the high temperature caused by strong friction within 5 minutes.

We should know that the speed of turboshaft engine is very high. Even if there is a reduction gear control, the speed of transmission is amazing. As a result, the helicopter transmission system has been in high-speed operation, and the supporting bearings naturally have to bear the friction and high temperature.

Because of this, the stable operation of the helicopter lubrication system is very critical, because it can not only reduce the friction coefficient of the transmission system, increase the number of revolutions, but also use the lubricating oil to cool the bearing ball and ensure the safety of the bearing.

But as the saying goes, the moon has its ups and downs, and people have their ups and downs. The lubrication system on the helicopter is very complicated. What should we do in case the lubricating oil breaks down one day?

Do you want to watch the bearing ball in the helicopter break, and the helicopter transmission gets stuck and falls down directly?

Designers naturally do not want such a thing to happen, so how to make the bearing run smoothly for half an hour under the extreme conditions of poor lubricating oil or even no oil, so as to make the helicopter land safely has become the goal of designers and engineers.

Therefore, since the 1960s, superalloy steel has replaced the original low carbon steel as the main material of high-performance bearing ball, and the effect is naturally good. However, the problem is that the superalloy steel is added with nickel, chromium, cobalt and other metal materials, and the special requirements of metallurgy and heat treatment, resulting in the high cost of this kind of bearing.

In addition, in addition to high temperature resistance, the friction coefficient, thermal expansion rate and creep resistance of this kind of high-temperature alloy steel are not significantly improved compared with low carbon steel. In addition, the heavy quality of this kind of high-temperature alloy steel makes helicopter designers dissatisfied.

Under this background, industrial ceramic materials, which started in the 1950s and gradually matured in the 1960s and 1970s, began to enter the vision of helicopter designers and engineers.

After some experiments and demonstrations, they found that a ceramic material called silicon oxide has diamond like hardness, the same strength as steel, and the same lightness as aluminum. The most important thing is that these properties have no obvious change at a high temperature of more than 1200 ℃.

Such a good thing is obviously the ball material that helicopter bearings dream of.

"In this respect, the Americans are still powerful. They have been widely used since the late 1970s. By the mid-1980s, all the newly produced helicopters in the United States were equipped with silicon nitride ball bearings. The Europeans would be far behind. When I visited Europe, they just started demonstration tests. As for ourselves..."

Professor Zhao sighed and immediately picked up the silicon nitride balls in his hand. He looked a little dazed but excited. He turned his head and looked at Zhuang Jianye and others: "I thought we had to make silicon nitride ball bearings in the middle and late 1990s. I didn't expect that you Tengfei group had made such important technological achievements Didn't see you publish it? Is your manuscript withheld by someone? Tell me directly, if it's true, old man, I'll fight for justice for you. "

At the beginning, Professor Zhao was very calm. He could say that he had a decisive momentum, and his face was even more terrible. It was obvious that he was really angry.

It's no wonder that Professor Zhao's reputation for Tengfei group was very polarized when he was in Beijing. Now he had never heard of such a core achievement that could make the domestic helicopter technology take a big step forward. This made him think that it was deliberately aimed at Tengfei group.Seeing Professor Zhao's appearance, Zhuang Jianye just wanted to explain, but before he could figure out how to use his words, he saw Liu Chun sitting beside Professor Zhao with a smile. A word almost made Zhuang Jianye's heart rise to his throat: "you are older than me, so I'll call you brother Zhao. To tell you the truth, let's make these silicon nitride ball take-off aviation technologies The R & D center has never thought of publishing these things as technical achievements. For them, these are the gadgets that are taken out after the failure of the experiment to transform the achievements and earn some pocket money. They don't care at all, so it's normal that you can't see them, brother Zhao. "

Zhuang Jianye would like to rush over and press the old Liu Chun, and then sew up the blind mouth. Dare you say that, would you not be afraid to turn Professor Zhao's eyes over again?

If you don't say anything else, Professor Zhao is as dull as a thunderbolt at this moment. You know that the old man's trembling liver is shocked again.

In fact, Professor Zhao thinks that the silicon nitride bearing is already great, but it's just a product of failure in rentengfei group. It's used for pocket money.

Professor Zhao is nearly 80 years old. For the first time, he feels that his three outlooks have collapsed. He deeply doubts whether his life has been in vain. Such cutting-edge things are all products of failure. What is a helicopter that he has been engaged in all his life? Miserable world?