The cardan joint is a part of the transmission, providing torque transmission from the motor to the gearbox of the bridge. The cardan consists of a hollow thin-walled pipe, on one side of which a spline connection and a movable fork are placed, and on the other - a fixed hinge fork. The number of sections varies depending on the type of gearbox and brand of car. The design of the single-section version includes two tips with crosses, the central part, as well as additional details:
- fasteners;
- gaskets, oil seals and other intermediate seals;
- sliding fork;
- double cardan joint;
- outboard bearing.
Destination
The functions of the shaft are not limited to the transmission of torque, it also acts as a support for some parts of cars. The steering universal joint can have various dimensions depending on the model of the car and its features. For the manufacture of steel is most often used. It provides maximum functionality with small size and weight. One of the elements of the power part of the shaft is a hinge, which can have an unequal and equal angular velocity. Unequal speed elements may have a rigid or elastic structure. The cardan joint of equal angular velocities has a specialized dividing lever, a double or cam design, or dividing grooves.
Torque
On shafts and axes intersecting at an angle of no more than 4-5 degrees, the force is transmitted from the hinges with an elastic plan. In this case, the occurrence of deformations on the connecting parts contributes to a deterioration in the quality of functioning and an increase in oscillation. The transmission of torque from products of uneven speed and a rigid plan is carried out sequentially, using movable joints of rigid elements. They are equipped with two forks, which have a tight fit with the shaft, and cylindrical holes used to place the crosses. The ends of the crosses, while the shaft and the cardan joints 1/2 are moving, begin to sway in a plane perpendicular to them. They are necessary to provide a flexible, reliable and strong connection between the drive axle and the crankshaft.
Of particular importance is the sufficient flexibility of the connection, as it provides free movement during movement of the vehicle. Cross elements consist of several spikes, retaining rings, needle bearings and oil seals. They are distinguished by a long period of operation and rarely fail, but their construction is negatively affected by poor-quality road surface, during which movement variable loads increase. To maintain functionality in such conditions, double cross joints are used. The rotation of the mating shafts, which change the angle with respect to each other, depends on them. The highest coefficient is observed at a value within 20 °. With a larger parameter of the angle of rotation, serious stresses fall on the crosspiece, oscillations also occur and the shaft balance deteriorates.
Principle of operation
The design of the splined joint of the cardan is of no less importance. The principle of operation is as follows. The gearbox is tightly fixed on the inside of the body and attached to the edge of one shaft. On the other side is a gearbox bridge connected to the suspension. The gap between the two nodes expands when overcoming uneven sections. Both the rear and front cardan need to be stretched, this action provides a spline connection, complemented by a sealing gland.
Additional items
In addition, the design includes an outboard type cardan bearing . It plays the role of an auxiliary support element for the shaft. The bearing prevents rotation of the part and ensures that it is in the desired position with the bracket, coated with grease and supplemented with sealing elements, which is mounted on the body. The number of shaft structural elements determines the number of bearings.
Cardan joint of heads necessary, first of all, to ensure high-quality connection of the drive axle and crankshaft. Flexibility and strength of connection become most relevant when shifting the bridge during the movement of the car.
Imbalance
Among the main irregularities in the shaft, imbalance is most widespread. Its occurrence is promoted by poor-quality fixing of gaps of crosspieces during installation and non-observance of operating rules. Often incorrect fixing of gaps occurs at the stage of production assembly. Imbalance does not occur immediately, an imbalance develops at first, which can be determined by vibration during gear shifting. It has a noticeable effect on the ball structure and contributes to intensive wear of the main elements of the system. The result is a deterioration in vehicle balance and an increased likelihood of a traffic accident. Therefore, it is recommended to comply with the rules, to conduct a systematic inspection of the shaft, including the universal joint and cross elements, to carry out timely repairs when worn parts are found.
Causes of extraneous noise
A fairly common phenomenon is the occurrence of knocking when shifting gears, changing the speed mode and when starting to move. The reason for this is the deterioration in the reliability of the coupling and the threaded connection of the fastening flange elements. Also, the cause may be a damaged universal joint and an increase in the installed clearance in the bearings of the crosspieces and spline design. The spider may contribute to the rattle. To prevent it, it is necessary to regularly replace the part (on average every 10 thousand km), inspect for grease and absence of damage. The gland of the outboard bearing is somewhat less likely to fail, and the hinge of the driveshaft gaining more clearance.
Splined elements
Even if the operating conditions are observed, there is always a chance of splitting. This is facilitated by the formation of backlash as a result of stretching the transfer chain. The chain at this time begins to jump over the teeth of the distributor and form a high shock load on the splined elements of the distributor and cardan. The occurrence of such a breakdown can be determined by the sharp metallic noise that comes from under the car. Slot cutting is possible both on budget and on original elements, so it is necessary to change the part in a timely manner to ensure full shaft travel. The universal joint 1/2 during the movement of the car makes reciprocating movements in relation to the razdatka, this is facilitated by stretching and reverse reduction of the body.
What you need to know
Premature cutting of the slots can be prevented by installing a new cardan with an elongated splined connection, but the period of operation of the detailed design will be increased by no more than 2-3 years. At the same time, another problem remains unchanged - an extended chain of handouts. That is why the cardan and the chain must be replaced at the same time. It is also worth paying attention to the properties of the flange located on the razdatka, if there is a need for repair. Of particular importance is the diameter of the slot depth, the outer diametric size, the number of splined joints and the overall dimensions.