Cardan joint: characteristics, description and device

The cardan joint is a part in the transmission that ensures the transmission of torque from the motor to the bridge reducer. The cardan consists of a hollow thin-walled pipe, on one side of which there is a slotted joint and a movable fork, and on the other - a fixed fork of the hinge. The number of sections varies depending on the type of gearbox and the brand of cars. The design of the single-section version includes two tips with crosses, a central part, as well as additional details:

• Fasteners;
• Gaskets, seals and other intermediate seals;
• Sliding fork;
• Double universal joint;
• Suspension bearing.

Purpose

The shaft functions are not limited to torque transmission, it also acts as a support for some car parts. The universal joint can have different dimensions depending on the model of the car and its features. For the production of steel is most often used. It provides maximum functionality with a small size and weight. One of the elements of the power part of the shaft is the hinge, which can have an unequal and equal angular velocity. Elements with unequal speed can have a rigid or elastic design. The cardan joint of equal angular speeds has a separating specialized lever, a double or cam construction, or separation grooves.

Torque

On the shafts and axes, intersecting at an angle of not more than 4-5 degrees, the force from the hinges with an elastic plan is transmitted. In this case, the appearance of deformations on the connecting parts contributes to a deterioration in the quality of functioning and an increase in the fluctuation. The transmission of torque from products of uneven speed and rigid plan is carried out sequentially, by means of mobile connections of rigid elements. They are equipped with two forks that are tightly fixed to the shaft, and cylindrical holes used to accommodate the crosses. The ends of the crosses, at the time when the shaft and joints of the cardan 1/2 moves, start to rock in a plane perpendicular to them. They are necessary to provide a flexible, reliable and strong connection between the driving axle and the crankshaft.

Of particular importance is sufficient flexibility of the connection, as it provides free movement during the movement of the vehicle. Cross elements consist of several thorns, lock rings, needle bearings and oil seals. They differ in a long period of operation and rarely fail, but their design is adversely affected by poor-quality road surface, when moving along, the variable loads increase. To maintain functionality in these conditions, double cross hinges are used. It is from them that the rotation of the conjugate shafts that change the angle relative to each other depends. The highest coefficient is observed at a value within 20 °. With a larger parameter of the angle of rotation, there are serious loads on the cross, there are also oscillations and the balance of the shaft deteriorates.

Principle of operation

The design of the splined joint of the cardan is not less important. The principle of operation is as follows. The gearbox fits tightly on the inner body and joins the edge of one shaft. On the other side is the bridge reducer, which has a connection with the suspension. The gap between the two nodes widens when overcoming uneven areas. Both the rear and front cardan need to stretch, this action provides a splined joint, supplemented by a sealing gland.

Additional Items

In addition, the design includes a pivot bearing of a hanging type. It plays the role of an auxiliary support element for the shaft. The bearing prevents rotation of the part and ensures its location in the required position with the help of a bracket, coated with lubricant and supplemented with sealing elements, which is fixed on the body part. The number of shaft structural elements determines the number of bearings.

Cardan joint of heads It is necessary, first of all, to ensure a high-quality connection between the driving axle and the crankshaft. Flexibility and strength of communication are most relevant when the bridge is displaced during the movement of the car.

Disbalance

Among the main violations in the work of the shaft, the most widespread disbalance. It is caused by poor-quality fixing of gaps of cross-pieces during installation and non-observance of the rules of operation. Often incorrect fixation of gaps occurs at the stage of production assembly. Imbalance does not occur immediately, first an imbalance develops, which can be determined by vibration during the gearshift. It has a noticeable effect on the ball structure and promotes intensive wear of the main elements of the system. The result is a deterioration in the balance of the car and an increase in the likelihood of a road accident. Therefore, it is recommended that you follow the rules, perform a systematic inspection of the shaft, including the universal joint and cross elements, and perform timely repairs when parts are worn.

Causes of extraneous noise

Quite common is the occurrence of a knock when changing gears, changing the speed limit and at the beginning of the movement. 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 pivot joint and an increase in the installed clearance in the bearings of the frogs and the spline structure. Crossings can contribute to the appearance of a rattle. To prevent it, it is necessary to regularly replace the part (on average every 10 thousand km), inspect for grease and damage. The oil seal of the suspension bearing is somewhat less likely to fail, and the joint of the propshaft Gains more clearance.

Splined elements

Even if the conditions of use are observed, there is always the possibility of cutting the slot. 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 dispenser and form a high shock load on the spline elements of the distribution and cardan. The occurrence of such a breakdown can be determined by the metallic sharp noise that comes from under the car. Cutting the slot is possible both on the budget and on the original elements, so you need to change the part in time to ensure the full stroke of the shaft. Cardan 1/2 joint during the movement of the car performs reciprocating movements with respect to the distribution, this is facilitated by stretching and reverse reduction of the body.

What you need to know

Premature cutting of the slot can be prevented by installing a new cardan with an elongated splined joint, but the period of operation of the detailed design will be increased by no more than 2-3 years. At the same time, the other problem remains unchanged: the stretched chain of the dispenser. That is why the cardan and the chain must be replaced at the same time. Also worth paying attention to the properties of the flange, located on the distribution, when there is a need for repair. Of particular importance is the diameter of the depth of the slot, the outer diametrical size, the number of splines and overall dimensions.