The universal joints are divided into several types. The universal joints are classified into non-uniform speed joints, quasi-constant speed joints and constant velocity joints according to the standard.
1 not constant velocity joints. When the angle between the two axes of the universal joint is greater than zero, the joint between the output shaft and the input shaft is transmitted at a varying instantaneous angular velocity ratio, but the average angular velocity is equal to the universal joint.
The cross-shaft rigid universal joint is composed of a universal joint fork, a cross shaft, a needle bearing, an oil seal, a sleeve, a bearing cover and the like. The working principle is that one of the rotating forks drives the other fork through the cross shaft, and can swing in any direction around the center of the cross shaft. The needle in the needle bearing can be rotated during rotation to reduce friction. The shaft input shaft (also called the master shaft) connected to the input power, and the shaft output shaft (also called the driven shaft) output through the universal joint. Working at an angle between the input and output shafts, the angular velocities of the two shafts are unequal, and as a result, the output shaft and the transmission components connected thereto are subject to torsional vibrations and affect the life of these components.
2 quasi-constant speed joints. Refers to a universal joint that transmits motion at equal instantaneous angular velocities at a designed angle and transmits motion at approximately equal instantaneous angular velocities at other angles. It is further divided into: a) double-type quasi-constant velocity joints. Refers to the universal joint when the length of the transmission shaft in the universal joint constant velocity transmission is shortened to the minimum. b) Bump type quasi-constant velocity joints. It consists of two universal joints and two differently shaped bumps. Two of the bumps correspond to the intermediate drive shaft and the two cross pins in the double joint joint device. c) Three pin type quasi-constant velocity joints. It consists of two three pin shafts, an active eccentric shaft fork and a driven eccentric shaft fork. d) Spherical roller type quasi-constant velocity joint. It consists of a pin, a spherical roller, a universal joint shaft and a cylinder. The roller can move axially in the groove to act as a telescopic spline. The roller contacts the groove wall to transmit torque.
3 Constant Velocity Joints The output shaft and input shaft to which the universal joint is connected transmit the moving universal joint at an instantaneous angular velocity that is always equal. It is further divided into:
a) Ball-fork constant velocity joints. A universal joint consisting of a ball fork with a raceway and a steel ball. The arc groove type ball type ball joint type universal joint refers to a ball type ball bearing ball which is a circular arc type universal joint. The structural feature of the section is that there are circular arc grooves on the active fork and the driven fork of the ball fork, and the two are combined to form four steel ball races, and the ball track accommodates four steel balls. The centering steel ball is mounted in the spherical groove at the center of the main and driven forks. Straight groove type ball joint type universal joint means that the steel ball raceway on the ball fork is a straight groove type universal joint. Its structural feature is that there are straight grooves on the two ball forks, each straight groove is inclined with the center line of the shaft, and the inclination angles are the same and symmetrical with each other. There are 4 steel balls in the raceway between the two ball forks.
b) Ball cage constant velocity joints. According to the axial movement of the universal joint, it can be divided into an axially non-retractable (fixed) ball cage universal joint and a retractable spherical cage universal joint. The inner surface of the star-shaped sleeve of the structurally fixed type spherical cage universal joint is connected with the transmission shaft by an internal spline, and the outer surface thereof has six curved grooves as the inner raceway of the steel ball, and the outer raceway is On the inner surface of the spherical shell. One of the six raceways formed by assembling the star sleeve and the spherical shell is equipped with one steel ball, and the six steel balls are placed in the same plane by the cage (ball cage). The power is transmitted from the drive shaft through the steel ball and the spherical shell. The structural feature of the retractable ball cage universal joint is that a cylindrical straight groove is formed on the inner wall of the cylindrical shell and the outer portion of the star sleeve, and a steel ball is arranged in the raceway formed after the two are assembled. The steel balls are also mounted in the holes of the cage. The inner sleeve of the star sleeve is splined for connection to the input shaft. This configuration allows the star sleeve to move relative to the simple shell in the axial direction.