The whole technology of dental disc focuses on three aspects: dental disc, crank and central axis system. Next, I will give you a detailed explanation in the form of pictures and texts.
First of all, let's look at the following three kinds of dental plates, which can be said to be representative products, namely, Shimano's MC20, LX570 and RACEFACE EVOLOCE XC. Let's analyze these dental discs from three aspects. 1 disk
First, let's take a look at the MC20 denture.
MC20' s tooth plate adopts three layers of rigid teeth, which has good wear resistance and low price, and is suitable for station wagons that need long-distance riding. However, due to the elasticity of steel itself, it is easy to deform at the moment of hard stepping, which will make players feel soft, and the weight of steel chips is large, which is not suitable for lightweight and high-rigidity competitive cars.
This is LX57 1 dental plate from Shimano. LX57 1 adopts two layers of aluminum alloy teeth, and the small plate is rigid. Many people think that teeth made of aluminum alloy will not be strong enough and will be easily damaged. In fact, aluminum alloy has good rigidity after heat treatment, and it is not easy to deform when it is trampled, and it can also have high strength when it reaches sufficient thickness. And because of its light weight, it is widely used in high-grade off-road vehicles.
LX's disk is die-cast, but because of the grade, the most advanced processing technology is still not adopted. Therefore, some heavy players will still feel a little soft when using it.
This is RACEFACE's EVOLVE XC dental tray, which is also made of two layers of aluminum alloy. But you can see that it is obviously different from LX. Its teeth are made by CNC (Computer Numerical Control), which is the most advanced processing technology. The thickness, hardness and appearance grade of teeth have been greatly improved, and they are widely used in various brands of high-grade dental plates.
Let's take a look at the top XTR952 dental tray. As can be seen from the second picture, the XTR disk and the fixed crank claw are connected together, and the thickest part of the connection even reaches 7MM, plus the ultra-high hardness 7075 aluminum alloy is used. This extreme practice makes the rigidity of the tooth piece reach an amazing level. So many DH even use 952 dental discs.
Second, the crank
If the work of the toothed plate is the same, then the articles made by major manufacturers on the crank have their own merits. First, let's look at a crank with toothed plate that we are familiar with. This is the crank of MC20 toothed plate. As you can see, the crank is forged with thick aluminum alloy. No problem with strength, the weight is not so optimistic. So how to reduce the weight while ensuring sufficient strength? Let's see how Shimano does it.
This is a technology used by Shimano on the cranks of DEORE and above, called HOLLOWTECH, which is an integrated hollow crank technology. The characteristic of this technology is that the crank is evacuated from the inside, so that there is a hollow throttle inside the crank, and then the strength of the crank is ensured by more advanced materials. This technology has greatly reduced the weight of the toothed plate. Now it has developed to the second generation.
So how do other manufacturers deal with Shimano's technology? Let's take a look at RACEFACE's approach.
As you can see, the crank design of this toothed plate is very different from that of MC20. It is hollowed out at the back of the crank, and the cross section of the crank is somewhat similar to an I-shape. This technology is called external hollow design, which is simpler than Shimano's internal hollow design, and the longitudinal strength is not greatly affected by the conceptual cross section.
If this design of RACEFACE is not obvious, let's take a look at the crank of PROWHEEL.
PROWHEEL's crank is shaped like a chicken leg, with a lot of holes in the back. This design greatly reduces the weight, but because the cross section of the crank has not been reduced much, it has little effect on the stiffness. The crank rigidity actually used by this kind of toothed plate is quite good.
If tooth technology and crank hollow design are grade differences, then the innovation of Zhongzhou technology can be called a qualitative leap, and the advanced transmission system technology can be seen from the way the central shaft is adopted. Let's take a look at the mounting holes of the following dental discs. The first is the technology of square hole center shaft. Before 1996, the dental discs of major manufacturers were widely used, from the lowest TY to the highest grade and DA. The advantages of this kind of central shaft are convenient maintenance and low price. The disadvantage is that the contact area between the tooth plate and the central axis is relatively small, and stepping on the tooth plate hard will deform and feel not tough enough. Moreover, in order to ensure the strength, a relatively strong shaft must be used, and it cannot be hollowed out, so there is no advantage in weight. This technology has fallen behind now and will only be used in relatively entry-level systems.
However, there are exceptions. CAMPAGNOGLO, Italy has always insisted on using the traditional square hole shaft, from the lowest xenon gas to the highest grade carbon fiber crank. CAMPAGNOLO has always maintained such a tradition in the denture system. By using very good materials and free processing, his denture has become tough, which is quite different from other manufacturers' ideas. The second is Shimano's unique OCTLINK spline shaft system. The so-called spline shaft is to make the contact surface between the shaft and the crank round, and then fix it with protruding splines. Compared with the square hole shaft, the contact area between the spline shaft and the toothed plate is obviously increased, and the pressure can be reduced under the same strength, and the crank and shaft will not become soft. And the weight can be reduced under the same conditions, so that the weight of the whole system can be greatly reduced.
Shimano's flower spindle system has been used in DA7700 system since 1996, which is a very mature spline system. Because it has eight splines, it is also called an 8-key system. This system is unique to Shimano, and the central axis is only produced by Shimano. As far as I know, there are FSA and compatible models.
The third is a more advanced spline system, called "Islamic State" system. Compared with Shimano's OCTLINK, the number of splines in the Islamic State system has increased from 8 to 10, and the width has also increased from 5 mm to 1 cm, which is theoretically higher in strength. Moreover, this patent is open, and many manufacturers produce "Islamic State" shafts and toothed plates.
I'll believe that when I see it. The following is the central axis of these dental discs. Please pay attention to the shape of their shaft ends, and you can understand them well by combining what I said above.