Demystifying the helical gearbox, why do heavy-duty trucks and airplanes use it?
Gears are one of the most common parts in trucks, mostly used in important components such as gearboxes, engines, and rear axles. The gears are rich in functions, allowing the power to be transmitted in any direction, and can also instantly change the speed and torque. It can be said that there is no modern automobile civilization without gears.
However, in all types of gears, helical gears are extremely unique, so that they have provided great help for the development of vehicles and aerospace fields. Then what surprises and challenges does its appearance bring to our lives? ? Let's have a good chat today.
What exactly is a helical gear?
The name helical gear is mainly different from spur gears. As the name implies, it is "gear with inclined teeth". The tooth surface of this type of gear is not parallel to the axial direction, but has a certain angle. It is precisely because of this. The included angle gives helical gears a variety of characteristics that are different from spur gears.
What are the advantages of helical gears?
In the automotive field, helical gears are widely used in mechanical components such as engines and gearboxes. The main effect is to increase meshing and make the transmission more stable.
In terms of mechanical characteristics, the working mode between spur gears is an infinite loop of "sudden loading-sudden exit", either without meshing, and once meshing, the maximum torque will be released.
Because of the inclined teeth of the helical gear, the meshing process of each tooth adopts gradual contact, the contact area spreads from the point to the surface, and the meshing torque increases from small to large, and then from large to small.
The gearbox with helical gears has less impact, smoother and lower noise.
In terms of user experience, helical gears can play a role in reducing the impact of shifting, making the vehicle smoother in driving, less frustrated, and at the same time lower noise.
It is no exaggeration to say that the large number of applications of helical gears is an important measure in the history of automobile development. It represents that automobile research and development work has begun to expand towards the comfort level of users, rather than simply pursuing the mechanical level of vehicles.
The advantages of heavy load are obvious, and the helical gearbox has been developed in China.
Due to high load carrying capacity, helical gears are more suitable for heavy loads
In terms of performance improvement, helical gears have a greater degree of coincidence than spur gears (increases with the increase of gear width and helix angle), which brings stronger load-bearing capacity to the vehicle and the limit of load The torque is greater, so the advantage in the field of high-speed and heavy-duty is very obvious.
For a long time, "heavy load" has always been one of the key labels of China's road transportation, and because helical gears have outstanding performance under heavy load conditions, truck manufacturers have also started helical gears a long time ago. Application in gearboxes.
As early as 2009, China National Heavy Duty Truck broke through the technical difficulties of double countershaft helical gear "tooth" technology and successfully developed the HW19710XS gearbox, which laid the foundation for the development of a fully helical gearbox with full synchronizer.
Speaking of my country's full helical full synchronizer gearbox, Fast's S series products are definitely a representative product. It is not only Fast's first gearbox that can withstand a torque of more than 2400NM, but also the earliest in China. One of a batch of gearboxes that match engines with more than 500 horsepower.
Smaller size, fewer teeth, a large number of applications in the aerospace field
Helical gear can achieve fewer teeth and smaller volume
In addition to the advantages mentioned above for the truck industry, helical gears also make a significant contribution to the aerospace industry due to their structural advantages. This is because the helical gear has the characteristic of "the least number of teeth without undercutting", that is to say, under the premise of ensuring the normal meshing of the gear, the number of teeth can be less and the volume of the gear can be made smaller.
However, precision aerospace equipment such as rockets, airplanes, and artificial satellites have strict requirements on weight, structural volume, and transmission performance. Naturally, helical gears will be used as much as possible to meet the design requirements.
Is axial force too annoying? Mining machinery adopts "human" shaped gears
However, everything has its two sides. The same is true for helical gears. It is also due to the inclination of the tooth surface. This type of gear produces axial force during operation, and the greater the helix angle, the more obvious the axial force, so its transmission efficiency Not as high as spur gears, and the wear of long-term meshing is more serious than that of spur gears.
"Person" shaped gears are widely used in mining machinery
Although the wear of helical gears can be solved by improving the gear material, the axial force is the inevitable result of the laws of physics. In the field of trucks, the axial force generated by helical gears is small, which is not enough to affect the normal operation of vehicles. In ultra-high-power equipment such as mining machinery, "herringbone" gears are more commonly used. This type of gear not only has the high load-bearing capacity of helical gears, but also offsets the axial force through the reverse combination of two sets of spirals.
Bronze "herringbone" gears in the early Han Dynasty
Gears have a very long history. As early as the beginning of the Han Dynasty, my country began the application of helical gears and "herringbone" gears. They not only constitute the earliest tools of mankind, but also are indispensable and important parts of today's most sophisticated machinery. Will also continue to promote technological progress in the future.
The above are some of my sharing, I hope to help you, if you are interested or have questions, you can contact us, we look forward to cooperating with you >> click here
