The working part of the universal joint is structurally characterized in that the outer spherical surface of the star sleeve is matched with the inner spherical surface of the corresponding cage, and the inner spherical surface of the bell shell is matched with the outer spherical surface of the corresponding cage. In this way, four inner and outer spherical surfaces form two groups of spherical pairs rotating around the same spherical center, and the spherical center coincides with the intersection of the input shaft (star sleeve) and the output shaft (bell shell). Generally, there are 6 ~ 8 steel balls to transmit force; Correspondingly, the cage also has the same number of rectangular windows evenly distributed along the circumferential direction, which are used to clamp the steel balls and guide the rotation angles of the two shafts. The axial side walls of each rectangular window (the working width of the rectangular window) are in interference fit with the corresponding steel balls. When the two shafts rotate, the length of each rectangular window ensures that each steel ball has enough moving space in the radial direction in the corresponding internal and external channels. On the outer spherical surface of the star-shaped sleeve, the same number of outer channels are designed, which are evenly distributed along the circumferential direction, the element lines are arc-shaped, and the cross section passing through the center of the channel is double eccentric arc (or ellipse) symmetrical about the center of the steel ball; Similarly, on the inner spherical surface of the bell-shaped shell, the same number of inner channels are designed, which are evenly distributed along the circumferential direction, the prime line is an arc, and the cross section passing through the center of the channel is a double eccentric arc (or ellipse) symmetrical about the center of the steel ball; The inner and outer channels are respectively contacted with the corresponding steel ball forks, so that the ball cage universal joint can still transmit motion and torque stably, reliably, flexibly and accurately under complicated working conditions such as a certain angular displacement (the limit angle can reach 45) of the input shaft (star sleeve) and the output shaft (bell shell). Another remarkable structural feature of the working part of the ball-cage universal joint is that the channel centers of the star-shaped sleeve and the bell-shaped shell are equal to the distance (called eccentricity) between the center of the outer spherical surface and the center of the inner spherical surface (the intersection of the two axes), and they are located on both sides of the center of the spherical surface (the intersection of the two axes) respectively.
Because of the above structural characteristics, the ball-cage constant velocity universal joint is widely used in automobiles, tractors, construction machinery, metallurgical machinery, textile machinery, machine tools and other fields. But before 20 10 years ago, the ball-cage constant velocity universal joint was mainly the traditional six-channel structure, and there were a few eight-channel structures. Due to the lack of systematic optimization design, after long-term use, two traditional ball-cage constant velocity universal joints have structural deficiencies and defects such as low bearing capacity, rapid temperature rise, large noise, large volume and impact resistance, which are difficult to solve.
In recent years, Shi, a famous expert on automobile transmission shaft at home and abroad, innovatively developed and designed the seven-channel ball-cage constant velocity joint, which initiated the structural design of the ball-cage constant velocity joint at home and abroad. Through theoretical analysis, long-term use and testing, the bearing capacity can be improved by 30%-40%, and the temperature and noise are greatly reduced. It has the outstanding advantages of advanced structure, reasonable and compact structure, stable, flexible and accurate work, high transmission efficiency, large limit angle, reliable use and impact resistance. It is a major breakthrough and expansion of the basic theory and product structure of the ball cage constant velocity universal joint. Over the years, Shi has published more than 60 papers on constant velocity joint and transmission shaft in various journals and magazines at home and abroad, and has more than 20 new technologies of constant velocity joint and transmission shaft assembly with independent intellectual property rights, among which seven-channel ball cage constant velocity joint is one of the important core patented technologies. In order to turn the new technology into a new industry, in 20 1 1 year, Shi initiated and established Zhejiang Transmission Co., Ltd. in cooperation with others, specializing in the production and sales of patented products of seven-channel ball cage constant velocity universal joints for automobiles, which are favored by domestic and foreign merchants and have huge market prospects. Its wide popularization and application will change the product and industrial structure of the ball-cage constant velocity joint and transmission shaft, lead and realize the product and industrial upgrading of the ball-cage constant velocity joint, and also drive the innovative development of related and similar products and industries, which is the development trend and direction of the automobile constant velocity joint and transmission shaft in the future.