Chapter 33 Failure Causes

Zhang Gong and Wang Gong are both automotive engineers, of course they look down on Li Weidong, a young car mechanic.

Even Wei Bin persuaded: Xiao Li, this problem of disengagement is actually very complicated. The engineers of our factory have been studying it for a day and a night, but they still haven't found the cause of the failure.

However, Li Weidong also despised Zhang Gong and Wang Gong in his heart. Both of them looked in their thirties. Judging from their age, they should be workers, peasants, soldiers and college students.

The state abolished the college entrance examination in 1966 and resumed it in 1978. The 12 college students recruited during this period were all college students of workers, peasants and soldiers.

The admissions of workers, peasants, and soldiers are based only on their background, not on their educational level. The poor and lower-middle peasants are given priority. Many of them can even get the math problems in elementary school wrong. Going to university is like going to a literacy class.

In the group of workers, peasants, soldiers and college students, many outstanding talents have also been born, but after all, they are individual elites. The overall level of workers, peasants, and soldiers is indeed a lot worse than the source of students recruited through the college entrance examination.

In the face of Zhang Gong and Wang Gong's doubts, Li Weidong decided to show his hand, so he pointed to the gearbox of the faulty car and said, The gearbox of this car should be imitated from abroad, right?

You guessed it right. Wang Gong nodded and continued: There are still many differences in design between foreign gearboxes and domestic gearboxes. It can be seen that this is an imitation of foreign gearboxes. , is not unusual.

Li Weidong did not refute, but went on to say: Is it a fake ZF gearbox from West Germany?

You still know ZF? Wang Gong's face showed a look of surprise. He didn't expect Li Weidong to be able to say ZF, which is not the knowledge that an auto mechanic should have.

When it comes to gearboxes, Li Weidong's first thought is of course ZF, Volkswagen, Mercedes-Benz, BMW, etc. All of them use ZF gearboxes. In the future, there will be many domestic independent brands that also use ZF gearboxes.

Then think of the Yellow River JN162 heavy truck, which absorbs the technology of Steyr, Austria, and Steyr uses a German gearbox, then it is not difficult to guess that the Yellow River JN162 is actually an imitation of ZF's gearbox.

In the future, it is not uncommon to know that ZF gearboxes are, after all, a Fortune 500 company and a top supplier of core automotive components.

But in 1984, China was still relatively closed, most people didn't know foreign countries, ordinary people couldn't even name a foreign brand, and it was impossible for auto mechanics to know ZF's gearboxes, they had to be professional cars Only engineers can know this kind of information.

When Li Weidong talked about ZF, Zhang Gong and Wang Gong suddenly put away their arrogance and dared not underestimate Li Weidong.

How do you know that we imitated ZF's gearbox? Zhang Gong asked.

If I can't even see this, how can I find the cause of the off-gear failure? Li Weidong replied with a smile.

Well, tell me, why does this car automatically disengage? Is it a problem with the gear bushing? Wang Gong asked.

Li Weidong shook his head: Of course it's not a problem with the gear bushing.

Wang Gong's face darkened, while Zhang Gong became excited: Haha, I just said it, it's a problem with the gear shift regulation.

Li Weidong still shook his head: It's not a problem with the gear gauge.

Zhang Gong also turned black.

Seeing that Gong Wang and Gong Zhang were about to join forces to anger Li Weidong, Li Weidong took the lead to pick up the tool, walked to the faulty car, and removed a component from the gearbox.

Li Weidong showed the parts to everyone and said at the same time, This is the reason why the fourth gear automatically disengages.

Is this a self-locking spring? Wei Bin instantly recognized the part.

Yes, it's a self-locking spring for fourth gear.

Li Weidong handed the parts to Wei Bin's hands.

The self-locking spring is not a difficult part to machine, and many manufacturers can make it. In the entire transmission, it is not an important part compared with the gear and the transmission gauge.

Wei Bin took the self-locking spring, looked at it carefully, checked it again, and then said, Xiao Li, you may have made a mistake in your judgment. The spring is not broken.

I thought you had any good ideas! Did you hear that? This spring is good, not broken! Wang Gong sneered again.

Li Weidong pointed to the self-locking spring and explained: This spring is not broken, but it is soft! It is because the self-locking spring is too soft that the vehicle will automatically disengage when it is in fourth gear.

After thinking for a few seconds, Wei Bin said, The situation he mentioned is indeed possible. If the self-locking spring is too soft, it will automatically disengage.

Li Weidong then asked: The batch of faulty vehicles that Yankuang repaired should have undergone level 3 maintenance not long ago, right? The gearbox must have been cleaned during level 3 maintenance, right?

Wei Bin nodded: Cars in coal mines have a lot of wear and tear, and their third-level maintenance will clean the gearbox.

This is the problem. Originally, the self-locking spring was in a tightened state, but when cleaning the gearbox, the gears and gear gauges need to be removed, and the self-locking spring is loosened. The material process of this spring It should not be up to the standard, if you release it suddenly, the tension exceeds the standard, and it will naturally become soft. Li Weidong explained.

Nonsense, the self-locking springs we use are all top-quality products! This time it was Zhang Gong who said.

Gong Zhang, I don't deny your statement. In China, this spring is likely to be of first-class quality, but can it meet the standards of West Germany? Don't forget, you are imitating West German gearboxes now! Li Weidong responded.

Then how do you know that there is a problem with the self-locking spring? Zhang Gong asked again.

Actually, when I saw that the gearbox was an imitation of a German gearbox, I had already guessed that the material process of the parts was probably not up to standard. And the gears, gear bushings and shift gauges were all replaced, so the most likely reason Possibly, it should be a self-locking spring. Li Weidong replied.

Then how do you prove that the disengagement is because of the self-locking spring? Wang Gong asked a very stupid question.

Li Weidong looked at Wang Gong helplessly, and then said: You have to prove this, you take this and the self-locking spring, go to the laboratory to test it, and then compare it with Steyr's data, you will know Is it the truth!

The self-locking spring is just an inconspicuous small component. Before that, the engineers of the Yellow River Factory also checked the self-locking spring of the gear, but the spring was not damaged, so they did not consider the spring softening.

And in the engine, the self-locking spring is not a component that is prone to failure. Even if the gearbox gear is worn out, the self-locking spring will still be very strong.

However, the engineers of the Yellow River Factory overlooked one thing. The gearbox used by the Yellow River JN162 is a copy of the German ZF gearbox, so the standard of the parts in the gearbox should also reach the German level.

The same domestic self-locking spring is no problem in a domestic gearbox, but in a German-designed gearbox, the material technology is not up to standard.

Although the Yellow River factory imitated the German gearbox, it could not imitate the advanced German material technology.

Even if it is completely copied from the German design and made of domestic materials to form a gearbox, the appearance looks similar, but the service life and failure rate are very different.

For an experienced automotive engineer like Wei Bin, he certainly knows the importance of material technology. Before that, he had been thinking about whether there was a problem with the design, but after Li Weidong reminded Wei Bin, he immediately thought that it might be because the material technology did not meet the standard.

This is actually a layer of window paper, and it will break when you poke it.

After thinking about this, Wei Bin said, Xiao Li, you go to my office and sit for a while. I'll go to the laboratory to test the elasticity and tension of this spring.

After Wei Bin finished speaking, he took the spring, took Zhang Gong and Wang Gong, and ran towards the laboratory without looking back.

...

Although Li Weidong knows how to repair cars, he can't tell at a glance that the reason for the disengagement is because the self-locking spring is too soft.

The reason why Li Weidong dared to make such a judgment is because in his previous life, Li Weidong repaired the Yellow River JN162 heavy truck.

In 1986, Qinghe Transportation Company finally introduced 10 Yellow River JN162 heavy trucks, along with a booklet called Yellow River JN162 Heavy Truck Repair Manual, which is Li Weidong's trump card.

This repair manual introduces the possible faults and maintenance methods of the Yellow River JN162. As long as the repairman holds this manual, he can repair the car according to the right medicine.

The reason why the repair manual is given with the car is mainly because there are many small faults in the Yellow River JN162. After all, it is a domestic heavy-duty truck, and its technology is much worse than that of imported heavy-duty trucks. It is normal to have many minor problems.

For this reason, the Yellow River Factory had to specially compile a repair manual. Anyone who buys a car will send a repair manual, which can be regarded as providing after-sales service.

For auto mechanics, this repair manual greatly simplifies the work process and reduces the workload. And many of the faults described in the repair manual can also be applied to other vehicles. It can be said that the auto repair manual is equivalent to a simplified version of the auto repair textbook.

At that time, Li Weidong was still working as an auto mechanic, and because of work needs, he memorized the contents of the repair manual by heart, but after so long, he could not remember what was written in it.

When Li Weidong heard the argument between Zhang Gong and Wang Gong, and saw the faulty vehicle, he recalled the cause of the fault recorded in the repair manual.

As for Li Weidong, he said that he guessed that the craftsmanship was not up to standard, which was entirely an explanation after the fact. Faced with a known result, it is easy to put a reasonable explanation on it.

...

Wei Bin hurried into the laboratory.

Wei Gong, you stayed up all night yesterday, let's get some sleep and come back! an engineer said.

I'm not sleepy yet. Wei Bin took out the spring, and continued, This is the self-locking spring for the fourth gear, which was just removed from the faulty car. Hurry up and test it.

The engineer took the spring and turned around to test it, but Wei Bin added: Size, lying test, vertical test, etc. are all omitted, and the physical performance test is directly carried out. Zhang Gong, you go together, Give me the data when the test is over.

Zhang Gong nodded and followed.

Wei Bin also ordered: Wang Gong, go to the reference room and find out the data of the self-locking spring of the Steyr gearbox, and we will compare it later.

Wang Gong agreed and turned around to the reference room.

After a while, after the test was completed, the two points of data were compared, and the results were clear at a glance.

It's really the problem with the self-locking spring! Wei Bin muttered to himself.

Zhang Gong and Wang Gong were embarrassed.

I was really hit by that auto mechanic!