The development process of the gear reducer and the reason analysis of the broken shaft

- Mar 11, 2021-

Nowadays, the industry has risen rapidly and machinery has developed rapidly. As a result, reducers can be seen in almost all types of mechanical transmission systems, from vehicles, ships, automobiles, locomotives, heavy machinery used in construction, and machinery industry. The processing machinery and automated production equipment, to the common household appliances, clocks and so on in daily life... I will share with you the development history of the gear reducer.

   From the 1970s to the 1980s, the world's reducer technology had a great development, and it was closely integrated with the development of the new technological revolution.

   Since the 1960s, my country has successively formulated standards for a number of general-purpose reducers such as JB1130-70 "Cylindrical Gear Reducer". In addition to self-made and supporting use by the OEM, a number of professional reducer manufacturers have also been formed. At present, there are hundreds of enterprises producing reducers in the country, with an annual output of about 250,000 general-purpose reducers, which have contributed to the development of my country's mechanical products.

Most of the reducers in the 1960s were made with reference to the technology of the Soviet Union in the 1940s and 50s. Although they have developed later, they are limited to the design, technological level and equipment conditions at that time, and their overall level is far from the international level. .

   Since the reform and opening up, my country has introduced a number of advanced processing equipment, and gradually mastered the design and manufacturing technology of various high-speed and low-speed heavy-duty gear devices through the introduction, digestion and absorption of foreign advanced technology and scientific research. Material and heat treatment quality and gear processing accuracy have been greatly improved. The manufacturing accuracy of general cylindrical gears can be increased from JB179-60 level 8-9 to GB10095-88 level 6, and the manufacturing accuracy of high-speed gears can be stabilized at 4-5 level. After some reducers adopt hard tooth surfaces, the volume and mass are obviously reduced, and the carrying capacity, service life, and transmission efficiency have been greatly improved, which plays a great role in energy saving and improving the overall level of the host.

  The power of the high-speed gear reducer (increaser) designed and manufactured by our country has reached 42000kW, and the gear circumferential speed has reached more than 150m/s. However, the technical level of most reducers in my country is not high, and old products cannot be replaced immediately. The coexistence of new and old products will take a long time.

  Analysis of the reasons for the broken shaft of the planetary gear reducer

   If the output shaft of the planetary gear reducer breaks, except for the planetary reducer shaft broken due to the misalignment of the output end assembly of the planetary reducer, the general situation will be the following two reasons:

  1. The wrong selection results in insufficient output torque of the planetary reducer.

Some users mistakenly think that as long as the rated output torque of the selected planetary reducer meets the working requirements, it is not true. First, the rated output torque of the equipped motor is multiplied by the reduction ratio, and the value obtained is in principle less than The rated output torque of the planetary reducer provided in the product catalog is similar. The second is to consider the overload capacity of the drive motor and the maximum operating torque required in practice.

  2. In the process of acceleration and deceleration, the momentary torque on the output shaft of the planetary reducer exceeds 2 times its rated output torque, and this acceleration and deceleration are too frequent, which will eventually cause the reducer to break the shaft.

  Theoretically, the maximum operating torque required by the user must be less than 2 times the rated output torque of the planetary reducer, especially in some applications, which must be strictly abided by. This is not only to protect the planetary reducer, but also to prevent the output shaft of the reducer from being twisted. The main reason is that if there is a problem with the installation of the equipment, and the output shaft of the planetary reducer and its load are jammed, the overload capacity of the drive motor will still make it continuously increase its output, which may cause the force on the output bearing of the planetary reducer to exceed The output shaft of the planetary reducer is twisted by twice the rated output torque.