With the rapid development of China’s economy, mining machinery, engineering machinery, marine engineering equipment and other heavy machinery and equipment are widely used in energy, marine, transportation, metallurgy and other fields. Due to the simple structure, direct transmission and other characteristics of heavy-duty gear and rack transmission, it has been fully applied in these equipment. The core technology of these large-scale equipment was almost monopolized by foreign countries a few years ago. With the continuous development of domestic technology, these large-scale equipment has begun to be localized. As the core components of large-scale equipment, the reliability of transmission components plays a vital role in the performance of equipment.
The most fatal failure form of heavy load gear transmission is tooth breakage, which will bring immeasurable losses to heavy equipment. Therefore, improving the bending strength of the gear is the primary consideration. For heavy load gear rack and pinion transmission, the transmission mode with large module and small number of teeth is usually adopted. For example, for the climbing gear of a jack up drilling platform, the basic number of teeth in the industry is 7, the module is 80, 100 mm, etc, Determined according to the size of the platform bearing capacity; For the bulldozing heavy load gear rack transmission of large excavators, the number of teeth is usually 14, and the modulus is 40, 50 mm, etc.
At present, there is no design standard to refer to and no mature calculation software to calculate the strength of these large modulus heavy-duty gear and rack transmission designs. At present, the design still calculates the tooth root stress through finite element method. If the strength calculation fails, the design process is very complicated by re designing the tooth shape, re modeling, and then carrying out finite element analysis and calculation. This paper studies the influence of tooth profile parameters on tooth root stress and wear resistance, derives the calculation formula of tooth profile design, and derives a quick calculation method for tooth root stress. The gear rack in the content refers to the gear rack with heavy load and large modulus.