Hypoid gear is a deviation from bevel gear, hypoid gear originated from the special development of the automobile industry. Can increase the diameter of the small wheel, easy to achieve double span support, using the small wheel lower offset, can reduce the center of gravity is comfortable car. Using the offset on the small wheel can make the off-road vehicle more powerful. Looks a lot like a spiral bevel gear. However, it is complex in design and most difficult to produce on bevel gear generators.

Tooth shape characteristics of hypoid gear

Smoothness: The tooth shape of a hypoid gear is surrounded by two perpendicular surfaces. This curved shape can effectively reduce the contact deformation of the gear mesh, thereby improving the transmission accuracy and operation. At the same time, the tooth shape of the hypoid gears can also make the change of the mesh Angle of the two wheels smoother, reduce the impact and vibration in the transmission, and reduce the noise of the gear.

Stability: Hypoid gears have higher transmission efficiency, less tooth surface contact fatigue and deformation, less tooth surface wear, better lubricity, lower noise and improved transmission stability compared to other transmission devices.

High precision: hypoid gears have characteristics that are difficult to match with ordinary gears, so they have been successfully applied in some fields. For example, ultra-precision instruments such as astronomical telescopes, as well as high-performance mechanical equipment such as high-speed trains, power ships, spacecraft, and machine tools. They all require a high degree of accuracy and reliability, and hypoid gears just meet this need.

Advantages Of Hypoid Gear 

In the front-drive model, the main reducer is generally composed of two cylindrical gears; On the front and rear drive models, the main reducer is composed of a set of bevel gears, and its biggest feature is that it can change the direction of power transmission by 90 degrees. According to the different models, the main reducer drive gear can be generally divided into straight bevel gear, spiral bevel gear and hypoid gear (commonly known as hyperbolic gear) three kinds. Hypoid gear is the most widely used one

The main characteristic of hypoid gear is that the driving bevel gear axis of hypoid gear is offset to a certain degree from the driven gear axis, which is different from spiral bevel gear. It can reduce the position of the active bevel gear and drive shaft, so that the body and the center of gravity of the vehicle are reduced, which is conducive to improving the driving stability of the car; The offset of the gear also makes the number of teeth of the driving gear can be less, and a pair of gears can obtain a larger transmission ratio; The overlap coefficient of the hyperboloid gear meshing is relatively large, the working strength is higher, the carrying capacity is large, the noise is smaller, the transmission is more stable, and the service life is long.

Disadvantage Of Hypoid Gear

Hyperboloid gear also has some disadvantages, that is, when hypoid gear works, there is a large relative slide between the tooth surfaces, and its movement is both rolling and sliding, so the pressure between the tooth surfaces is large, and therefore the lubricating oil is very high. In use, special attention should be paid to only the special hypoid gear oil, and the use of ordinary gear oil is prohibited, otherwise it will be damaged by rapid and severe wear of the tooth surface. In practice, we have encountered many faults that cause abnormal wear of the main reducer due to adding wrong gear oil.

Hypoid gears have strict requirements for meshing clearance and meshing marks of gears. The general mesh clearance standard is 0.15~0.40mm. The mesh mark should reach more than 50% of the tooth length, and the position is controlled in the middle of the small end of the tooth, 2~4mm from the small end. The meshing impression in the direction of the tooth height should be greater than 50% of the effective tooth height, and 0.8~1.6mm from the top of the tooth.