Cardan joint: characteristics, description and device

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

The cardan joint is a part of the transmission that provides torque transmission from the motor to the axle gearbox. Cardan consists of a hollow thin-walled pipe, on one side of which there is a spline connection and a movable fork, and on the other side there is a fixed hinge fork. The number of sections varies depending on the type of gearbox and car brand. The one-piece design includes two crossheads, a center piece, and additional parts:

• fasteners;
• gaskets, oil seals and other intermediate seals;
• sliding fork;
• double universal joint;
• outboard bearing.

Purpose

The functions of the shaft are not limited to transmitting torque, it also acts as a support for some car parts. The cardan steering joint can have different dimensions depending on the model of the car and its features. Most often steel is used for manufacturing. It provides maximum functionalitywith small size and weight. One of the elements of the power part of the shaft is a hinge, which can have unequal and equal angular velocity. Elements with unequal speed may have a rigid or elastic design. The CV joint has a dedicated release arm, twin or cam design, or split grooves.

Torque

Shafts and axles intersecting at an angle of no more than 4-5 degrees are subjected to force from 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 transfer 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 that have a tight fit with the shaft, and cylindrical holes used to accommodate the crosses. The ends of the crosses, while the shaft and cardan joints 1/2 are moving, begin to sway in a plane perpendicular to them. They are necessary to ensure a flexible, reliable and durable connection between the drive axle and the crankshaft.

Sufficient flexibility of the connection is of particular importance, as it allows free movement during the 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 on theirthe structure is negatively affected by poor-quality road surface, when driving on which variable loads increase. To maintain functionality in such conditions, double cross hinges are used. It is on them that the rotation of the mating shafts depends, which change the angle with respect to each other. The highest coefficient is noted at a value within 20 °. With a larger rotation angle parameter, serious loads fall on the cross, oscillations also occur and the shaft balance deteriorates.

Working principle

The design of the spline connection of the cardan is no less important. The principle of operation is as follows. The gearbox is tightly fixed on the inner body part and attached to the edge of one shaft. On the other side is the axle gearbox, which is connected to the suspension. The gap between the two nodes expands when overcoming uneven areas. Both the rear and front gimbals need to be stretched, this action provides a splined connection complete with 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 required position using a bracket, coated with grease and supplemented with sealing elements, which is mounted on the body part. The number of structural elements of the shaft determines the number of bearings.

Gimbal jointheads are necessary, first of all, to ensure a high-quality connection between the drive axle and the crankshaft. The flexibility and strength of the connection becomes most relevant when the bridge is displaced while driving.

Unbalance

Among the main violations in the operation of the shaft, imbalance has become the most widespread. Its occurrence is facilitated by poor-quality fixing of the gaps of the crosses during installation and non-compliance with the operating rules. Often, incorrect fixation of gaps occurs at the stage of production assembly. Unbalance does not occur immediately, first an imbalance develops, 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 increase in the likelihood of a traffic accident. Therefore, it is recommended to follow the rules, to systematically inspect the shaft, including the universal joint and cross elements, to carry out timely repairs if worn parts are found.

Causes of extraneous noise

A fairly common occurrence is the occurrence of knocking when shifting gears, changing speeds and when starting to move. The reason for this is the deterioration of the reliability of the coupling and the threaded connection of the fastening flange elements. Also, the reason may be a damaged cardan joint and an increase in the set clearance in the bearings of the crosses andslotted design. The crosspiece can contribute to the appearance of grinding. To prevent it, it is necessary to regularly replace the part (every 10 thousand km on average), inspect for lubrication and no damage. The outboard bearing oil seal fails somewhat less often, and the cardan shaft joint acquires a larger clearance.

Spline elements

Even if the operating conditions are observed, there is always the possibility of cutting off the splines. This is facilitated by the formation of play as a result of stretching the transfer chain. The chain at this time begins to jump over the teeth of the transfer case and form a high impact load on the splined elements of the transfer case and cardan. The occurrence of such a breakdown can be determined by the metallic sharp noise that comes from under the car. Cutting splines is possible on both budget and original elements, so it is necessary to change the part in a timely manner to ensure the full stroke of the shaft. The cardan joint 1/2 during the movement of the car performs reciprocating movements in relation to the transfer case, this is facilitated by stretching and reverse contraction of the body.

What you need to know

Premature shearing of splines can be prevented by installing a new gimbal with an extended spline, but the service life of the detailed design will be increased by no more than 2-3 years. At the same time, another problem remains unchanged - an extended transfer chain. That is why the cardan and chain must be replacedsimultaneously. 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 are the slot depth diameter, external diametral size, number of spline joints and overall dimensions.