Cardan transmissions used in many trucks and passenger cars. And if we take into account all kinds of agricultural machinery, then the cardan transmission has found a very wide application. As you know, it has a movable mount, so both the leading and steerable wheels cars have the ability to move relative to the body in a vertical plane. However, they also have an elastic, but rather rigid attachment to. However, the gearbox and drive wheels are connected to each other. And this connection is carried out through a cardan transmission.

Main purpose cardan transmission is the transmission of rotation from power unit through the gearbox to the drive wheels of the car, which can also be steered. Cardan transmission provides a rigid connection to the gearbox output shaft and does not interfere with the operation of the suspension. In other words, the cardan transmission of the car allows you to transmit torque with variable alignment of the articulated units.

Cardan transmission device

The cardan transmission is drive and driven shafts, which are connected by a flexible hinge. The flexible articulated joint allows rotation to be transmitted smoothly when the angle between the two shafts changes slightly. According to the type of hinge joint, there are two types of cardan drives:

• outdated unequal hinges angular velocities;
• more modern constant velocity joints.

A cardan transmission based on unequal velocity joints is most often used to connect the output shaft and the drive axle in rear-wheel drive cars and trucks. In addition, such hinges are used for connecting and other auxiliary equipment. Constant velocity joints, which are more advanced in design, are used in modern front and rear four-wheel drive vehicles. Through such cardan drives, the driving wheels of the machine are connected to.

The cardan transmission with unequal angular velocity joints has the following design elements:

• driving, driven and intermediate cardan shafts;
• crosses (hinges);
• suspended and intermediate supports.

The hinge itself consists of two so-called forks located on the shafts and a cross - the connecting element of the forks. When assembled, the shaft forks are located at an angle of 90° relative to each other and are connected by a cross, which has four cups with needle bearings at the ends. The presence of needle bearings ensures normal functioning of the hinge at different shaft deflection angles. However, the largest angle between the shafts for a unequal velocity joint is usually no more than 20°. During assembly, the bearings are filled with grease, which is designed for their entire service life.

If we consider, for example, the cardan transmission of a rear-wheel drive VAZ car, then its design has two hinges, an intermediate shaft and a suspension support intermediate shaft. Due to its, so to speak, imperfect design, the unequal velocity joint does not have the constructive ability to ensure constant (at a constant speed) rotation of the driven shaft relative to the drive shaft. During one revolution of the hinge, the driven shaft is twice delayed and twice overtakes the drive shaft. In addition, it is worth considering that the unevenness of rotation directly depends on the angle between the shafts; the larger it is, the more pronounced the unevenness is. However, to eliminate this deficiency a second similar hinge and an intermediate shaft with support are installed. The second joint compensates and equalizes the speeds of both shafts.

A cardan transmission with constant velocity joints, more often called a CV joint, has a more advanced design and ensures rotation of the shafts at a constant speed relative to each other, regardless of the changing angle between the axes of rotation. A cardan transmission with such hinges has an almost similar device:

• drive, intermediate and driven shafts;
• CV joint;
• connecting elements.

As already mentioned, the CV joint has a slightly different design than the connection with the cross. The most common ball CV joint consists of the following elements:

• hinge body;
• clip;
• separator;
• balloons;
• retaining rings, clamps and boot (protective cover).

The CV joint housing has a spherical internal cavity, in which there are grooves for balls. The housing is molded integrally with the shank, which is designed to connect to the wheel hub or gearbox. The CV joint cage also has grooves for balls and a hole for mounting on intermediate shaft. The separator, as in a conventional bearing, holds the balls in the required position. Due to the grooves in the body and holder, the hinge is able to transmit rotation evenly at shaft deflection angles up to 35°.

CV joint has much longer period service rather than a hinge with crosspieces in the design. The main condition for long-term service is the presence of a sealed boot and a sufficient amount of special grease inside the hinge. If damaged protective boot, the CV joint loses its tightness, loses lubrication and fails very quickly.

Application of constant velocity joints

As mentioned above, CV joints are most often used to connect the drive wheels and the differential of the drive axle, which is mounted in the gearbox housing (in the case of a front-wheel drive car). has two CV joints in its design. However, two hinges are needed not to compensate for rotation, as is the case with hinges on the cross, but to ensure that the wheels move in a vertical plane and turn them.

IN rear wheel drive cars CV joints have also found their use. As you know, the rear axle of a car has a rather bulky and heavy structure. On modern cars imported production instead rear axle a small-sized and lightweight housing with a differential is installed in the form of a beam, which is connected to the drive wheels via CV joints. In addition, this design allows for the implementation of a full-fledged independent rear suspension.

There is no absolute opinion regarding the history of the creation of the CV joint. The essence of one of the most common is that in 1927 this device was invented and patented by Alfred Rzepp. Therefore, the mechanism itself is still called the “Rtseppa” hinge among professional amateurs. Already towards the end of the 60s, front-wheel drive cars became especially interesting for developers almost immediately of all significant automobile concerns. Interest was aroused by the layout of their body, which repeatedly allows them to offer the driver and the passengers themselves maximum space in the vehicle.

So, to provide drive to the front steered wheels without depriving them of the ability to turn, experts came up with such a complex mechanism as a CV joint. The abbreviation stands for "constant velocity joint". Interesting detail, unusual term. The device itself provides for the solution of the following problem - the transfer of uniform rotational motion from one axle axis to another, if they are located at an angle to each other. The most important thing is that the location of the axle shafts is at a certain angle. Its value usually undergoes constant changes, not exceeding 70 degrees.

The designs of the constant velocity joint are different; there are several of them. At the moment, there are several modifications of the CV joint. So, ball-type CV joint is the most common. It appeared for the first time in the twenties of the last century. A popular one is the cam CV joint, developed by the French inventor Gregoire. He patented his invention in the early twenties under the name “Tracta”. The next type of CV joint is a twin cardan. The scope of its application is cars made in the USA, also from the twenties. We are talking about Cord L29. They were also used for transmission French cars"Panhard-Levassor" in the 50-60s. At the moment, it is also used in the circuits of various vehicles that do not develop enough high speed, for example, tractors.

1. Purpose of the CV joint

The CV joint has its purpose. Its main task is to transmit uniform rotation at an angle. Thus, a constant velocity joint is used for independent suspension, which is on the front steered wheels. True, the following condition must be observed here - the wheels must be driving.

Since the CV joint is a composite part, it means that in addition to rotation, it is capable of providing a rotation angle within 70 degrees, allowing it to be used in the design of the drive axle.

Inner and outer CV joint

Let's try to figure out what they represent in the transmission front wheel drive cars internal and external CV joints. We will talk not only about the design features, but also about the mechanism for transmitting rotational motion from the box variable gears or a gear shaft to the drive wheels, requiring at least two hinges along the way. The fact is that having one CV joint for each wheel is not enough; you need a pair of them.

Therefore, let us recall once again that the design itself is necessary to ensure freedom of movement of the shaft. The inner CV joint is installed inside the gearbox housing, while the outer CV joint is installed near the wheel itself. Both CV joints are necessary for the vehicle to move successfully. However, there is a certain difference between them, which depends on the car model.

Let's try to figure out what the difference between them is. Firstly, the internal one is larger in size, and therefore costs more. Its main purpose is to transmit rotation from the transmission to the shaft. External CV joint must rotate the wheel hub because it has mounting splines. Absence sufficient quantity free space repeatedly forces specialists to make it much smaller in size.

2. Design and principle of operation of the CV joint

As for the standard set of hinge components, it is as follows. There are only four parts, so the mechanism itself is simple.

- a body similar to a spherical bowl and a driven shaft;

Inner race as spherical fist and drive shaft;

The separator is like a ring with special holes in it. It is necessary to hold the balls;

And the balls themselves - six pieces.

Despite the fact that there is complete diversity constructive solutions CV joints, their operating principle remains unchanged. Namely, contact points that transmit circumferential forces. They must be located in the bisector cavity, which passes through the bisector of the angle that the shafts form.

Let's try to understand how the CV joint works. However, in order to understand this principle of operation, it is necessary to understand what components it consists of and how it works.

The CV joint operation process involves the following stages:

1. There are spherical grooves on the inner race and in the body. Their number coincides with the number of balls;

2. It is quite possible to hold the balls with a separator that is located in the fist-body vector space. Then they move along the outer diameter of the housing grooves. As for the inner diameter, here the balls move along the grooves of the fist;

3. By rotating the drive shaft, you can transmit force to the cage through the fist and balls that are in the grooves. This power is then transmitted to the driven shaft;

4. As a result of changing the angle between the driven and drive shafts, the balls move very freely along the grooves, thus continuing to transmit force.

3. Advantages and disadvantages of CV joints

The CV joint is lightweight, relatively reliable, and can be easily replaced in case of breakdown. Its advantage is that, in comparison with other similar mechanisms, thanks to the help of the hinge, only a slight loss of power is possible.

The disadvantage of the CV joint is the presence of a boot in the design. It is necessary to keep the device clean while also serving as a container for lubricant. This is its protective function.

The CV joint is located in a place where it is impossible for it to come into contact with other foreign objects. The boot may also be torn. This can happen while driving, for example, when driving over an obstacle, or on a rut that is too deep. Only the car owner himself can find out about this. Usually he realizes this when the dirt is already inside the boot, having got there through a crack. This can lead to increased wear and tear. If the car owner is sure that this happened quite recently, the CV joint can simply be removed by washing it thoroughly. When replacing the boot, it must be filled new lubricant. In the event that the trouble did not occur recently, the CV joint must fail ahead of time.

Since we are interested in the ball joint, we will consider its structure. Due to the fact that the elements are not in oil (unlike the rear axle), the device is called “dry”. The design of the ball joint is quite simple.

What does a CV joint consist of:

• Frame. It is a hemisphere, a bowl. The driven shaft is installed in it.
• Bottom part. This is a sphere-shaped cam with a drive shaft.
• Separator. This is a ring with holes into which metal balls are installed and held there.
• Metal balls. Movable elements. There are 6 of them.

Which CV joint to choose

Before you buy new CV joint, you should find out about the types (what they are), which ones are better according to driver reviews, and what the prices are. The main emphasis should not be placed on the price when purchasing this element of the car device.

There are the following companies CV joint manufacturers:

• Pilenga. According to reviews, it's a good option.
• Febest. According to reviews from drivers who bought inexpensive price Spare parts from this company quickly fail.
• Metelli. Recommended.
• Loebro. Recommended.
• SKF. Recommended.

The characteristics of CV joints are different. There are 23 splines in the design, and there are 24. If you make a mistake, the wrong one (the difference is one tooth) will not fit on the shaft.

High quality new spare part differs from the new one in appearance and touch. A defective CV joint has a thin boot, little lubrication, and a weak clamp securing it.

Signs of CV joint failure

Thanks to the presence of a boot in the CV joint device, it is protected from dust, moisture and dirt.

Causes of failure of constant velocity joints:

1. Torn boot.
2. Using poor quality or unsuitable lubricant.
3. Defective metal.

If crunches, clicks, or grinding sounds (metal on metal) appear while driving, then this is nothing more than a sign of a broken CV joint. These sounds appear when mechanical particles get into the bearings through a torn or blown boot and the balls jam.

The video shows the device and how to replace CV joints with your own hands.

Often, owners of front-wheel drive cars, in the process of studying the structure of their car, discover interesting names of parts that they had never even heard of before. The category of unusual terms includes CV joint. This material will examine in detail this concept, the principles of its operation, and types. And the first thing that needs to be done within the framework of this topic is to give an explanation of what a CV joint is in a car.

The previously mentioned mysterious name is nothing more than an abbreviation for such a rather large phrase as a constant velocity joint. The main purpose of this device is to transport rotational movements from one axle shaft to another. A prerequisite for this is that these semi-axes are at a certain angle to each other, the value of which undergoes constant changes, but, as a rule, does not exceed 70.

As for the history of the creation of the CV joint, then, as is the case with many other things invented long ago, there is no absolute opinion. The most common is that in 1927 this device Invented and patented by Alfred Rzepp. By the way, the mechanism is called the “Rtseppa” hinge, and the word “grenade” acts as a popular driving slang.

It should also be noted that the CV joint can be found in cars with rear-wheel drive and all-wheel drive designs. But here two things come into play mandatory conditions: the presence of a rigid mounting of the gearbox, which is located in the rear of the car, and an independent suspension, which is on the rear wheels.

This mechanism Among professional car enthusiasts it is considered simple. It usually consists of four parts:

• housing in the form of a spherical bowl, plus a driven shaft;
• the inner race, which is a spherical fist, plus the drive shaft;
• a separator, which can be explained as a ring with special holes, designed to hold the balls;
• six balls.

This standard set of hinge components makes it possible to transfer rotational motion as smoothly as possible. In addition, every car owner should be aware of the lack of this ability in universal joint axle shafts, although it performs the same function as a CV joint.

As for the principle of operation of the CV joint, it can be characterized as follows:

• spherical grooves are located in the body, as well as on the inner race, and their number is equal to the number of balls;
• the balls are held by a separator, and they are placed in the space between the fist and the body;
• the balls move with the help of the grooves of the body along the outer diameter, and with the help of the grooves of the fist - along the inner diameter;
• the force generated during the rotation of the drive shaft is transmitted to the holder, then to the driven shaft using a fist and balls located in the grooves;
• the balls continue to transmit forces quite freely, moving along the grooves, after changing the angle between the drive and driven shafts.

To maintain cleanliness, and therefore the safety of both the device itself and the car as a whole, it is recommended to cover the CV joint with a boot. Most often, the protective function is faithfully performed by a rubber lining, which prevents water, dirt and other unnecessary substances from entering the rotating parts of the mechanism.

Like any other device, especially one located in a car, the CV joint has certain advantages and disadvantages. As for the first, we should talk about a significantly lower loss of power compared to a rear-wheel drive design, low weight and easy replacement. But the disadvantages of this unit are wear during the starting process. Also, the CV joint is significantly inferior in power to the bridge.

The operation of any “grenade” in a car constantly occurs under heavy loads, so the elements of this device are made of heavy-duty materials in order to wear out more slowly.

But this still will not ensure the eternal service of the CV joint. Due to various reasons (aggressive driving, ingress of unnecessary substances in the form of dust, water and dirt), the hinge may stop functioning. To prevent this you need to know the following points. Firstly, the first sign of some problems in the operation of the CV joint is the appearance of an unusual crunching sound when the car makes turns and sharp accelerations. The first thing to do in this case is to inspect the drive. This process consists of anthers for any damage or lubricant leakage from under them. After this, it is necessary to check the condition of the bearings by shaking them in different directions. An indicator that not everything is in order with this device is a clear feeling of play. Therefore, the next step is to replace the inner CV joint.

Types of hinges

Various sources offer various classifications CV joint. But in general, it is possible to identify the distribution of types, which car owners will be able to focus on in the future. First of all, it is necessary to distinguish the hinges depending on their location. So, each drive must have an external and internal hinge installed.

A more extensive classification of hinges is as follows:

Video “How to lubricate the inner CV joint”

In the recording, a car enthusiast shows how to properly lubricate the inner CV joint.

Despite awareness modern drivers(and almost everyone has to become one when it fails “ iron horse"), almost no one has heard of a spare part called a CV joint. Well, those who have already become acquainted with it have probably already spent quite a large amount Money to replace it or best case scenario repair. In this article we will talk about these so cunning and important automotive components, and also reveal the secret of their long, trouble-free operation.

What is CV joint

What is a CV joint in a car? Translated into “folk” language, it is designated as “grenade”. Therefore, if the car has such replacement part, then sooner or later it will explode. Okay, let's leave the jokes aside... However, let's not forget about the main thing. So, a CV joint or “grenade” is a constant velocity joint. It is these spare parts that serve to transfer from the heart of the car (engine) to the drive wheels. These parts not only enable the wheels to “start their work after a command “from above” - from the motor,” but also completely control them.

Why still “grenade”? Firstly, this part very similar to a real grenade, and secondly, its actions are truly deadly. If, the vehicle will not be able to move independently until it is replaced or repaired.

CV joint device

The CV joint works almost the same way as the universal joint known to all drivers. Nevertheless, the second drive is more advanced and complex. What are the differences? In the case of a cardan: the transmission transmits torque asynchronously (that is, one shaft rotates evenly, while the other does not), and the crossing angle is quite difficult. The CV joint is different in that it does all this work, but is 90% simpler: it has a longer service life, since its rotation angles are no more than 70 degrees relative to the axis.

Important! CV joints originated more than a hundred years ago. However, today they have evolved greatly and are one of the main components of absolutely all vehicles that are found on the road (regardless of their “age” or high cost).

The grenade is a power spare part that is often subjected to stress. Therefore, she needs protection from environment, which lubricant can help with (and thus extend its service life). The design of the part is covered with a boot made of plastic or rubber (which is filled with lubricant and held on the shafts using clamps). Note that the life of the grenade also depends on the quality of the boot. If this component fails and you do not take any action, you will soon have to check the CV joint for serviceability (since it cannot work in an unprotected environment and fails quite quickly due to direct exposure to the environment: hit dirt, etc.)

How to choose a CV joint

Today there are several designs of this, among which the following should be highlighted as the most popular:

• tripod;
• turnip;
• crackers (cam);
• ball;
• paired.

Most often in modern vehicles It is ball spare parts that are found. Twin and cam are most often used by special equipment, trucks, as well as tractors.

Signs of CV joint failure

The first sign is a knocking, humming, rumbling (although the main sound is still a knocking), with the part where the part is, in general, ready to “fly out”. By the way, these sounds are quite enough to determine a CV joint malfunction (even without any checks at service stations).

It is worth remembering that a grenade can knock for a week or several months. In any case, sooner or later it will fail... and then - beware in the literal sense of the word. If this happens on the highway, it will be difficult to avoid an accident, but at lower speeds, a quick brake will save you...

When the CV joint falls out, it becomes almost impossible to drive the car! Initially, it is very difficult to turn the steering wheel in the direction from which it took off. Nevertheless, it is still possible to travel for some time (about half an hour). Then the car simply stops and can no longer move.

In this case, the car starts up as usual, the speeds are turned on, but the car does not respond to any of them. Initially, it may seem that the gearbox has failed, but this is not the case. If before this you heard a strong roar under one of the wheels, then it practically jammed (you’re lucky if it didn’t fly out completely), and then the gearbox stopped working, then it’s absolutely just a grenade - there’s no need to worry (it’s the CV joint that needs to be changed, but not a box, which will cost much less).

In any case, it is important not to bring your car to this state... It is better to repair it at the first sign, rather than then pay for repairs, and wait another week for repairs (while being without a car at this time and being forced to travel by public transport).

Well, now you know what a grenade in a car is and what it represents. Now, after reading this article, you know how to check the internal CV joint yourself without overpaying for the services of professionals. We hope this article was useful to you. Good luck!

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