Any all-wheel drive or rear-wheel drive car has this element. After all, without it, it would be impossible to transmit torque to the rear axle. The driveshaft is the most important part that is included in the vehicle transmission. This mechanism transmits rotation from the gearbox to the rear axle gearbox. With full confidence, the driveshaft can be called an intermediate link or a vehicle support.
Using a driveshaft to transmit torque from the gearbox allowed engineers to: Position the gearbox more than just parallel to the axles, making use of body space more efficiently. Transmit rotation to the drive axles evenly. Ensure a rigid connection between the secondary shaft of the gearbox and the drive wheels, without interfering with slight deformation of the suspension and movement of the wheels relative to the body, which inevitably occurs when driving over rough terrain. However, the cardan is used in cars for other purposes: as a steering element; to organize the selection of part of the torque; to switch between four-wheel drive and rear-wheel drive on some SUV models.
The main task of the cardan is to transmit rotation. Therefore, its main part is a long hollow tube, which is called the central shaft. The void in the center is needed to facilitate the structure. If the transmission is long enough, a pipe that is too heavy will cause beating and vibration. In such cases, it is divided into several parts, adding intermediate shafts. The driveshaft circuit must have an elastic coupling that compensates for the car's rocking while driving. It is installed at the point of connection to the gearbox. The flexibility of this part protects the transmission from impacts from heavy pipes. To engage the cardan with the main gear, the rear gearbox uses a sliding fork that can move back and forth. It allows you to change the length of the mechanism within a small range. To connect the shafts to each other and to the transmission parts, rigidly fixed forks are used - driving on one side and driven on the other. Crosses with needle bearings in each of the four tips are inserted between them. To secure the entire mechanism, grooves and splines are provided. There is usually a safety bracket located under the driveshaft in the car. It prevents the pipe from falling onto the road if one of the mechanism parts breaks. If the transmission has multiple shafts, each of them must pass through a support bearing that supports the structure and stabilizes its rotation. In addition to the main elements, cardans have other parts. Flanges are used to securely attach to the gearbox and rear axle. Oil seals - to seal connections and suppress vibrations. Safety couplings - for additional protection against stretching and impact. Covers prevent dust, dirt and stones from getting inside.
The type of cardan transmission depends on the purpose. The layout is developed at the design stage. The choice of why a driveshaft of a particular design is needed is determined by the technical characteristics of the car. In some cases, it is necessary to install a multi-shaft mechanism with several hinges. Asynchronous The asynchronous circuit is used in many cars with rear-wheel drive or all-wheel drive. Feature - during the movement, unequal angular velocities are formed. This is due to the connection of the two forks using a cross at a right angle. The secondary shaft lags behind the main shaft 2 times and overtakes the main one 2 times. To compensate, additional universal joints of unequal speeds are installed. They are mounted at the ends of the shaft. With this scheme, the angle between the pipes can be changed by up to 20°. Disadvantage: due to the complexity, frequent maintenance and repairs are required. Synchronous The solution to the problem of asynchronous models was CV joints - constant velocity joints. They have different designs. Pegout and Renault cars have a Tripod installed. In it, torque is transmitted through 3 spherical rollers. They slide in the grooves of the driven shaft fork. A special feature of synchronous cardans is the ability to work at deflection angles of up to 70°. Vibration is reduced and maintenance-free service life is increased. Disadvantages - there is a possibility of damage to the anthers off-road. Flexible and rigid semi-cardan transmission This is one of the types of cardan shaft, designed to compensate for angular turns, slight changes in the distance between the gearbox and the rear axle while driving. The elastic link is made of rubber-fabric material or rubber. Compensation for changes in angle occurs due to compression or stretching of this element. A rigid universal joint is rarely installed in cars. The reason is a low degree of reliability, increased noise during operation. The design is used to compensate for installation defects.
The first signs of a malfunction in the cardan are noise and increased vibration. Secondary “symptoms” are oil leakage at the junction of the shaft with the gearbox, and a knocking noise occurs when shifting gears. An overpass or inspection hole is required for inspection. You need free access to all elements and good lighting. Items that need to be checked: Fastenings. Checking the presence of the lock washer and the degree of its tightening on the nut of the intermediate support and flange connection. A possible defect is the appearance of play and vibration. Condition of the elastic coupling. Possible loss of integrity and mechanical damage. They affect the degree of compensation for displacements of the propeller shaft elements. Check - slowly rotate the cardan clockwise and back. There should be no play. The appearance of gaps between the sliding fork and the shaft. The reason is wear of parts. To control, you need to rotate the shaft with the coupling. If “beating” occurs or there is play, the sliding fork needs to be replaced. Hinges. It is convenient to check using a slotted screwdriver. It is inserted into the eyes of the forks. A sign of a malfunction - there is play when moving. Hanging bearing. If the bearing is beating while the shaft is swinging, this indicates that it needs to be replaced.
Finding a suitable cardan is not difficult; we recommend that car enthusiasts purchase a new one in the store. There are even several search options: by component code; by car VIN code; by key parameters of the car: make, model, year of manufacture and some parameters of the units.
It is extremely difficult to answer this question with certainty, because everything depends on many factors. From practice, we can highlight European products from one of the oldest companies producing driveshafts - Hermann Paus Maschinenfabrik, which makes it possible to drive up to 1 million kilometers without a single breakdown. Cardan shafts from Chinese manufacturers are often classified as bad and unreliable. As a rule, thinner pipes and spare parts made of lower quality steel are used there. Therefore, their reliability and resource intensity are extremely limited. If you need a new driveshaft with a manufacturer’s warranty, then contact a reliable, time-tested company!
