Classification of universal joints
Do you know what types of universal joints are there? The following is a brief introduction to the classification of universal joints. According to whether the universal joint has obvious elasticity in the torsion direction, it can be divided into rigid universal joints and flexible universal joints. Steel universal joints can be divided into unequal velocity universal joints (commonly used for cross shaft type), quasi-constant velocity universal joints (such as double-joint universal joints) and constant velocity universal joints (such as ball cage type) universal joint) three kinds.
Classification of universal joints
Unequal velocity joint
The cross-axis rigid universal joint is a variable speed universal joint widely used in automobiles, and the maximum allowed angle between two adjacent axes is 15゜～20゜. The cross shaft type universal joint shown in the figure below consists of a cross shaft, two universal joint forks and four needle roller bearings. The holes on the two universal joint forks 1 and 3 are respectively sleeved on the two pairs of journals of the cross shaft 2 . In this way, when the driving shaft rotates, the driven shaft can not only rotate along with it, but also swing in any direction around the center of the cross shaft, so as to meet the needs of changing the included angle and distance at the same time. A needle roller bearing 5 is installed between the cross shaft journal and the universal joint fork hole, and the outer ring of the needle roller bearing is axially positioned by the snap ring. In order to lubricate the bearing, a grease nipple is generally installed on the cross shaft and an oil passage leads to the journal. Lubricating oil can be injected from the grease nipple to the needle bearing of the spider journal.
The cross-axis rigid universal joint has the advantages of simple structure and high transmission efficiency, but it cannot transmit constant angular speed rotation when the angle α between the two axes is not zero.
When the following two conditions are met, the transmission from the output shaft of the transmission to the drive axle can be achieved.
structure
Lubrication seal, inner and outer retaining ring positioning
working principle
1. When the driving fork is in the vertical position and the cross axis plane is perpendicular to the driving axis. At this time, the linear velocity of the connection point a between the driving fork and the cross shaft and the connection point b between the driven fork and the cross shaft on the cross shaft plane are equal. (The velocity projection of the driven fork onto the plane of the cross axis).
2. When the driving fork is in the horizontal position and the plane of the cross shaft is perpendicular to the driven shaft. (Velocity projection of the active fork to the plane of the cross axis).
3. The relationship between the angular speed of the master and slave shafts.
