King of Industry

  Chapter 522 Common Mistakes Novices Make

   "First, let me tell you about the single-rope winding hoist."

   "This kind of hoist appeared earlier, and its mechanism is the simplest. Its working principle is: fix one end of the hoisting wire rope to the hoist drum, and the other end goes around the sky wheel on the derrick to connect with the hoisting container."

   "Using the different winding directions of the wire ropes on the two drums, when the hoist rotates, the two lifting containers are lifted up and down one by one to complete the lifting task."

   Zhao Guoyang explained a few words, and Yuan Qinghua, a Ph.D. from the Department of Fluid Mechanics, asked: "Mr. Zhao, after listening to your explanation, can we understand it this way?"

   "The most critical point of this single-rope winding hoist is the material of the wire rope?"

   "Well, your understanding is correct, but it is somewhat one-sided. After all, the mine hoist is an organic whole, and it is difficult to separate its parts."

  Zhao Guoyang tapped his fingers on the table and said: "However, you are not wrong about one thing. The material of the wire rope is not good enough. It is indeed a serious problem of our domestic mine hoist."

  Hearing this, Yuan Qinghua nodded silently, took out a pen at the same time, and made some notes in the notebook.

  Zhao Guoyang stared at him and continued to narrate.

  "Single-rope winding hoists are divided into single-drum and double-drum series. The core key is the main shaft device, rope adjustment clutch, and reducer."

   "As the main working mechanism of the single-rope winding hoist, its functions are as follows."

   "First, it is to wind the wire rope of the hoist; second, it is to bear various normal loads, including fixed loads and working loads; third, it is to bear abnormal loads caused by various positive conditions."

   Although Zhao Guoyang's narration has nothing fancy, it is clear and full of content, showing his solid basic knowledge.

  Listening to his narration, Li Zhaohe, who had been engaged in mining equipment for decades, couldn't help secretly admiring him.

   "Chairman, since the main shaft device is so important to the single-rope winding hoist, its performance requirements should also be very high?"

  Hearing the sound, Zhao Siyan couldn't help asking.

  Zhao Guoyang nodded approvingly and said: "Siyan, your question is very good. Indeed, the main shaft device is a very important part of the hoist."

   "Some mine hoist companies in the world also have high requirements for this component. These companies require that the main shaft device is absolutely not allowed to have incomplete deformation under the action of extreme loads."

  Hearing this, Liu Yan said in a loud voice: "This requirement should not be difficult to meet. We only need to use better materials for the spindle device, and the problem can be solved?"

   "That's right, but Liu, you should know that the material of the spindle of this mine hoist is different from the material of the spindle of ordinary machine tools..."

  Liu Yanliu frowned slightly, and said with some disdain: "Hmph, of course I know this. The commonly used material for shaft parts is 45 steel."

   "For shafts with high precision, 40Cr, bearing steel GCr15, and spring steel 65Mn can also be used. In addition, it is not uncommon to use ductile iron as shaft parts."

  After Liu Yan finished speaking, she glanced at Zhao Guoyang with demonstrative eyes, which meant to tell him that Miss Ben is not a vegetarian.

  Seeing the proud look of this brainy girl, Zhao Guoyang felt a little funny.

  Liu Yan caught a glimpse of Zhao Guoyang looking at her expression with a half-smile, and her face became a little ugly.

   Obviously, she misunderstood that Zhao Guoyang was taking the opportunity to "examine" her proud figure.

  Feeling the annoyance in Liu Yan's eyes, Zhao Guoyang coughed quickly to cover up his gaze, and then slowly opened his mouth.

   "Student Liu is worthy of being a top student in the Materials Department of Jingbei University. He has a comprehensive understanding of shaft materials, but..."

   "But what?"

  After hearing Zhao Guoyang's first paragraph, Liu Yan was still a little complacent, but when he said the word "but", Liu Yan's expression changed, and she couldn't help asking.

Zhao Guoyang put down the pen in his hand, put his hands together and said, "Student Liu seems to have overlooked one point. The spindle device of our mine hoist uses a high-speed, heavy-duty spindle, which is fundamentally different from the spindle of a general machine tool. "

   "This..." Liu Yan blushed upon hearing this.

   During her previous study, her understanding of the main shaft material was limited to some machine tools and ordinary machinery, and she did not have such a large-scale construction machinery as a mine hoist.

   Therefore, in the selection of materials, she made some mistakes that novices tend to make.

   Zhao Guoyang did not mean to mock her, he continued: "For the spindle under high-speed and heavy-duty environment, we generally choose low-carbon alloy steel such as 20CrMnTi, 20Mn2B, 20Cr or 38CrMoAL nitrided steel."

   "Although domestic steel factories can produce these kinds of materials, there are very few that can be supplied in large quantities and are of excellent quality..."

  When Zhao Guoyang said this, everyone in the conference room basically understood: the localization of the main shaft device of the mine hoist is probably the problem here.

  Seeing that everyone was silent, Zhao Guoyang smiled and said: "Of course, we all don't have to be discouraged by this."

   "As long as we optimize the design as much as possible, and then communicate with the steel mills carefully to let them manufacture carefully, there is still a great opportunity for the localization of the spindle device."

  After finishing this paragraph, Zhao Guoyang took a sip of water from his teacup, then turned his gaze to the students and asked, "Do you have any questions about what I just said?"

   "If there is, it's best to bring it up now. Although our time is not abundant, it is still necessary to help everyone sort out the clues."

   After Zhao Guoyang finished speaking, several students started discussing in low voices.

  Seeing how his students were seriously discussing, Ji Chongxuan nodded in relief.

   Not long after, the big man Kong Dezhong spoke first: "Mr. Zhao, I have a question. I wanted to ask it just now, but I never had the chance."

   Zhao Guoyang was amused when he heard the words, stretched out his hand and made a "please" gesture: "It's okay, student Kong, it's not too late for you to ask now!"

  Kong Dezhong nodded and confessed all his problems.

"Mr. Zhao, what I want to ask is about the single-drum and double-drum of the single-rope winding hoist. Can you explain to us the difference between the two and their respective structural characteristics? ?”

  Zhao Guoyang heard the words, "uh" and said: "Of course this is no problem. In fact, single and double drums are also called single cylindrical drums and double cylindrical drums in academics."

"For a single cylindrical drum, the structure is relatively simple. It is two steel wire ropes sharing a drum winding surface. The first steel wire rope is released from the drum, and the corresponding leak out of the drum surface is then wrapped by another steel wire rope. "

   "As for the double cylindrical drum, each of its wire ropes is wound on a specific drum, that is, at any time, the wire rope is only wound on half of the total winding surface of the two drums."

   "In this case, one roller is firmly fixed on the main shaft, and the other can be looped on the main shaft, and connected with the main shaft by means of a clutch, so that when necessary, the two rollers can be rotated relative to each other at the same time..."

  As soon as Zhao Guoyang finished speaking, Kong Dezhong said again: "Mr. Zhao, what is the use of the relative rotation of these two rollers?"

  Zhao Guoyang raised his hand and gestured: "The relative rotation of the drum can make the operation of the hoist easier, because it can easily adjust the length of the steel wire rope that is gradually elongated due to elastic deformation."

   "In addition, the relative rotation of the two drums can also compensate for the length cut due to periodic tests on the steel wire rope."

   "Therefore, on the surface of each drum, in addition to the length of the wire rope for lifting the height, a certain length of wire rope needs to be attached."

   "In this way, when the drum rotates relative to each other, the vertical length of one wire rope increases while the length of the other wire rope does not decrease..."

   Zhao Guoyang's vivid narration did not mention too many conceptual things, but he completely answered Kong Dezhong's question, which made the guy amazed.

  Xu Linlin and Chen Li, who were on the side, also praised secretly. Even Yuan Qinghua, who had the highest education, also looked at Zhao Guoyang with admiration.

   As for Liu Yan, although on the surface she is still unwilling to admit defeat, but in terms of the theoretical basis of the mine hoist, she is already convinced from the bottom of her heart.

   Just when Zhao Guoyang was about to continue to tell everyone about the next important part of the hoist—the reducer, Tang Wanru, who had never attracted much attention, suddenly spoke up.

   "Zhao...Mr. Zhao, I have a question, I would like to ask you to help me answer it!" Although Tang Wanru's voice was low, the firmness in her tone could be heard.

  Zhao Guoyang's eyes narrowed slightly, and then naturally fell on the opponent.

  Looking at the girl with a blushing face, Zhao Guoyang smiled and said, "Student Wanru, please tell me something. As I said just now, our meeting today is to communicate and discuss together."

   "So, you don't need to be restrained!"

   "What I want to ask is the material of the spindle device..."

  Logan's words did not surprise Zhao Guoyang.

   After all, she, like Liu Yan, is a top student in the Department of Materials. It is not difficult to ask more questions about materials.

   Thinking up to this point, Zhao Guoyang nodded slightly and said: "Student Wanru, please ask me!"

  Tang Wanru nodded lightly, and said in a soft voice: "Just now, after listening to Mr. Zhao, we all have a relatively intuitive understanding of the importance of the spindle device."

   "What I want to ask is, since the main shaft of the mine hoist has to bear various external loads and act on the base through bearings."

   "Then during the production process, the lifting container on the main shaft is heavily loaded, and when emergency braking or other sudden situations occur, the instantaneous load on the main shaft may far exceed the usual established rated load?"

   "If such a situation occurs, isn't it very likely that there will be a safety problem with this spindle?"

  (end of this chapter)