In the designs of modern independent suspensions, along with a spring or air spring, a torsion bar (torsion - torsion, translated from French) can also be used as the main elastic element. Torsion bar suspension provides the car with a number of advantages, the main of which are high smoothness and compact suspension. However, her significant shortcomings in the form of worse handling and rollability of the car, they do not allow the use of torsion bars in the bulk of modern passenger cars.

History of appearance

Torsion bar suspension has been used since the mid-1930s on cars. French brand Citroen. In the 1940s, torsion bars were used on racing cars Porsche.

Legendary french car Renault 16 with torsion bar suspension

Subsequently, they were used by many other automakers. For example, Renault, ZIL and Chrysler. The use of torsion bar suspension was primarily due to good performance smooth running and simplicity of design.

What is a torsion bar?

The torsion bar device is a metal shaft or rod that twists in one direction. In cross-section, the torsion bar can be round or square, less often plate-shaped - consisting of several layers that work together to produce torsion.

Elastic element of torsion bar suspension with fastenings

One of the ends of the torsion bar is rigidly attached to the suspension arm by means of a splined connection, the second is similarly fixed to the body or frame of the car. The axis of rotation of the lever and the axis of twist of the torsion bar are on the same line. Possessing a calculated resistance to torsion under load, the torsion bar holds the weight of the car and provides an effective elastic connection between the suspension and the body when the lever moves. The principle of operation of the torsion bar is also used in the stabilizer lateral stability with opposite suspension moves of one axle.

Round torsion shafts

The steel alloy from which the torsion bar is made has high performance elasticity and endurance, able to withstand long-term loads without deteriorating its properties. The length and thickness of the shaft also affects the performance and softness of the suspension. To protect against rust and destruction, the surface of the torsion bar is coated with a special anti-corrosion compound or a rubberized coating.

The principle of operation of torsion bar suspension

A torsion bar suspension works similarly to a spring, spring or air suspension. The spring element is a steel rod - a torsion bar. When the suspension operates, a force from the support arm is transmitted to the torsion bar, causing the rod to twist to a certain limit. After that elastic element returns to its original state, aligning the position of the lever.

Types of torsion bar suspensions

Front independent torsion bar suspension on wishbones

Design and principle of operation of torsion bar suspension

The front torsion bar suspension on wishbones (one or two depending on the design) consists of the following elements:

• A longitudinally located torsion bar that works to twist and replaces a spring.
• The lower or upper lever that takes the main load, through which force is transmitted to the torsion bar.
• Damping element - which performs the function of damping vibrations.
• , compensating body roll when driving.

Independent front torsion bar suspension with double wishbones Toyota Hilux Surf

The compactness of the front torsion bar suspension on wishbones allows for efficient use free space. For example, for installing massive wheel drives. In this regard, torsion bars have become widespread in production frame SUVs, combining cross-country ability with soft suspension. For example, Toyota Land Cruiser 100 (torsion bar fastening to the lower arm) and Toyota Hilux Surf (torsion bar on upper arm). Torsion bars are also used on the front axle commercial vehicles.

Rear independent suspension with transverse torsion bars

In rear suspension designs with longitudinal arms, torsion bars are installed transversely. Legendary French Renault car 16, produced until the 1990s, was equipped with a front suspension with longitudinal torsion bars, and a rear suspension with transverse bars.

Rear suspension with transverse torsion bars

A peculiarity of the elastic elements of the rear suspension was their location - one was behind the other, which structurally resulted in a difference in the wheelbase on the sides of the car (one of the wheels was several centimeters closer to the front). The car's handling and stability left much to be desired, but it was the compactness of the torsion bar suspension that made it possible to significantly increase the volume luggage compartment, which largely determined the popularity of the model. Currently, such a suspension scheme is not used by automakers.

Semi-independent rear torsion beam

Rear semi-independent U-shaped torsion beam

A semi-independent torsion beam with a U-shaped section, which has an integrated elastic rod, becomes more resistant to bending. At the same time, it allows the wheels of one axle to move slightly relative to each other when driving over uneven surfaces. This achieves improved handling and stability of the vehicle. This suspension is used on rear axle most budget front wheel drive cars.

Why is it needed?

Torsion bar suspension is an important option for any car, along with spring, spring, pneumatic and others.

Let us remind you that a car needs suspension in order to provide shock absorption when connecting the wheels of the car and its supporting system. The suspension performs another important function: it reduces the load on the wheels from the side road surface, stabilizing the position of the body when driving.

A little background

In the first half of the last century, around the 30s, the automobile manufacturer Volkswagen installed a design that was curious at that time on its Beatle model. As it turned out, it is a kind of prototype of a modern torsion bar suspension. This design was later improved by the scientist Ledvink from Czechoslovakia, and then was installed on Tatra cars.

Then Ferdinand Porsche became interested in it, and already in the 40s he reproduced this idea of ​​the professor and introduced it into mass production called "KDF-Wagen". Later, during the Second World War, this suspension was used in the design of tanks and other military equipment. IN post-war years Renault and Citroen became interested in torsion bars. However, soon, despite the ease of operation, the production of torsion bars became much more difficult, so they abandoned it. Currently, torsion bar suspension has become widespread in trucks and on SUVs from some Japanese and American automakers.

Device

The torsion bar suspension consists of metal shafts. They work on the so-called torsion. So, one end of the shaft is fixed to the chassis, and the other - to a special lever, which in turn is connected directly to the axle of the car. The torsion shaft is usually made of high-temperature steel. Due to its strength, this material can endure heavy loads without harm. The torsion beam (or shaft) can have two locations depending on the type of vehicle. For example, in passenger cars it is placed transversely. Most often, torsion bar suspension is found on rear-wheel drive passenger cars. On trucks, the beam has a longitudinal arrangement. However, despite the difference in location, the functions remain the same. Like other suspensions, the torsion bar affects the smoothness of movement, is responsible for adjusting the roll when turning, and reducing vibrations of the steered wheels. One

However, a torsion bar suspension in some cases also performs the function of automatic leveling with the help of an engine, which, in turn, tightens the torsion bar shafts to provide additional rigidity. This kind of design can be used when replacing a wheel. While all three wheels are lifting the car, the fourth one can be replaced without using a jack.

Advantages

Torsion bar suspension has some advantages over other types. For example, the service life of such a structure is much longer, and height adjustment is easier. This suspension is more compact and easier to maintain, which is the main advantage. If it becomes loose, it can be repaired using a standard wrench, which cannot be said about the spring suspension.

A torsion bar is a metal elastic element that works to twist. As a rule, this is a round metal rod with spline connection at the ends. A torsion bar can consist of a set of plates, rods, or beams of a certain section. Structurally, the torsion bar is attached at one end to the body or frame of the car, and at the other to the guide element - the lever. When the wheels move, the torsion bar twists, thereby achieving an elastic connection between the wheel and the body. A feature of torsion bars is that they rotate in only one direction - in the direction of twisting. Another feature is that the torsion bar can be used to adjust the height of the body. Torsion bars are used in various types independent suspensions: on double wishbones, on trailing arms, with linked trailing arms (torsion beam).

In a torsion bar suspension with double wishbones, the torsion bars are located parallel to the body, due to which their length and, accordingly, elastic properties can be adjusted within a wide range. One end of the torsion bar is attached to the lower wishbone (less often to the upper arm), the other end to the car frame. This design Torsion bar suspension is used as the front suspension of off-road passenger cars - some models of American and Japanese SUVs. In a torsion bar suspension with trailing arms, the torsion bars are connected to the trailing arms and, accordingly, are located across the body. This torsion bar suspension design is used as the rear suspension of some models of small class passenger cars. A special place in the design of torsion bar suspensions is occupied by the so-called. torsion beam or suspension with linked trailing arms. The guiding device of this suspension is two longitudinal arms, rigidly connected to each other by a beam. The trailing arms are attached to the body on one side and to the wheel hubs on the other. The beam has a U-shaped cross-section, therefore it has high bending rigidity and low torsional rigidity. This property allows the wheels to move up and down independently of each other. The torsion beam is currently widely used as a rear suspension for front-wheel drive small and medium-sized cars. Due to its design, a torsion beam suspension occupies an intermediate position between dependent and independent types of suspensions, which is why its other name is semi-independent suspension.

History of appearance

Torsion bar suspension began to be used in the mid-1930s on French cars. Citroen brand. In the 1940s, torsion bars were used on Porsche racing cars. Subsequently, they were used by many other automakers. For example, Renault, ZIL and Chrysler. The use of torsion bar suspension was primarily due to its good ride quality and simplicity of design.

Types of torsion bar suspensions

Front independent torsion bar suspension on wishbones The front torsion bar suspension on wishbones (one or two depending on the design) consists of the following elements: A longitudinally located torsion bar that works to twist and replaces the spring. The lower or upper lever that takes the main load, through which force is transmitted to the torsion bar. A damping element is a shock absorber that performs the function of damping vibrations.

Rear independent suspension with transverse torsion bars

Anti-roll bar that compensates for body roll when driving. The compact design of the front torsion bar suspension with wishbones allows efficient use of available space. For example, for installing massive wheel drives. In this regard, torsion bars have become widespread in the production of frame SUVs, combining increased cross-country ability with a soft suspension. For example,

Semi-independent rear torsion beam

Toyota Land

Cruiser 100 (torsion bar attached to the lower arm) and Toyota Hilux Surf (torsion bar attached to the upper arm). Torsion bars are also used on the front axle of commercial vehicles.

In rear suspension designs with longitudinal arms, torsion bars are installed transversely. The legendary French car Renault 16, produced until the 1990s, was equipped with a front suspension with longitudinal torsion bars and a rear suspension with transverse bars. A peculiarity of the elastic elements of the rear suspension was their location - one was behind the other, which structurally resulted in a difference in the wheelbase on the sides of the car (one of the wheels was several centimeters closer to the front). The car's handling and stability left much to be desired, but it was the compactness of the torsion bar suspension that made it possible to significantly increase the volume of the luggage compartment, which largely determined the popularity of the model. Currently, such a suspension scheme is not used by automakers.

A semi-independent torsion beam with a U-shaped section, which has an integrated elastic rod, becomes more resistant to bending. At the same time, it allows the wheels of one axle to move slightly relative to each other when driving over uneven surfaces. This achieves improved handling and stability of the vehicle. This suspension is used on the rear axle of most budget front-wheel drive cars.

✔ Difficulty in producing torsion bars. ✔ Mediocre vehicle handling. Currently, front independent suspension, where torsion bars are installed as elastic elements, is used in the production of trucks and SUVs not intended for dynamic driving. In addition, torsion bar suspension is successfully used in tank chassis designs and other special purpose vehicles. tracked vehicles.

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Modern cars are very different from those that were common when our parents were young. However, the main structural elements have been preserved. They have only been improved to the point that they are ready for normal everyday use. An example is the suspension.

Today you can find car models with pneumatic or spring suspension, as well as those that use spring type suspension. But the topic of our conversation today will be what a torsion bar suspension is and how it works.

Torsion bar suspension on a real car

General terms

Torsion bar suspension refers to special torsion-type metal shafts that work in torsion.

One of their ends is fixed to the chassis, while the other is mounted on a lever, which is fixed completely perpendicular, and is connected to the axle. The type of suspension in question is made from steel that has been pre-treated in the appropriate manner. temperature conditions. Thanks to this, during torsion, the suspension is able to withstand significant loads. In fact, the main principle of operation of this suspension can be considered the effect on bending.

As a rule, the torsion beam is located longitudinally or transversely. If we are talking about the longitudinal type of placement, then it is used on large cars. Most often, we are talking about trucks that place a significant load on the chassis. And here cars

Basically, they use a transverse arrangement of this suspension, and even on rear-wheel drive.

This type of suspension is also found on other vehicles. But, in both cases, such a suspension helps ensure fairly smooth movement, as well as regulate roll when cornering. This ensures the maximum damping of vibrations of both the wheels and the body. In addition, the vibration of the wheels, which are in this case

manageable.

Some car models use a torsion bar suspension to perform automatic leveling via a motor. It, as it were, tightens the beams, giving additional rigidity. The specific efficiency is determined by the speed of movement and the condition of the road.

The suspension, which can be adjusted in height, can be used when changing wheels. The fact is that a car or other vehicle is lifted by three wheels, while the fourth wheel will be lifted without the help of a jack.

Advantage of torsion bar suspension

Like any technology, torsion bar suspension has its advantages. We are talking about the fact that the operation of cars with this type of suspension turns out to be one of the longest. This is a result of the way the torsion bar suspension is designed.

Height adjustment In addition, you can adjust the height very easily. And compactness in width will serve a good purpose, as automobile manufacturers

, and those who will be involved in direct car maintenance.

Space saving

A suspension of this type, as a rule, takes up significantly less space than a spring suspension, which is called MacPherson strut. And, of course, it is important to remember that torsion bar suspension is one of the easiest to operate and maintain.

In a situation where such a suspension has become loose, it can be adjusted very simply. To do this, use a regular wrench. All you have to do is crawl under the car to tighten the necessary bolts. But here you need to remember that excessive tightening of the bolts can lead to a very rough ride of the car in the future. This is the main pros and cons of torsion bar suspension.

But what is a torsion bar?

Now we need to figure out what this torsion bar is, which became the basis of such a popular suspension. In fact, it is just an elastic element made of metal that, as we have already said, works to twist.

Basically, this is a metal rod that has a circular cross-section with a special spline type connection at its ends. In some cases, a torsion bar may consist of a set of plates and rods, as well as a beam that has the desired cross-section.

And this is what the torsion bar itself looks like

External view of a torsion bar from a Mitsubishi Pajero car

Very important feature The torsion bar can be considered to be that it can be used to adjust the height of the body. Of course, in high-tech cars this parameter can hardly be called very important, but many classic vehicles, as well as those cars that are designed to provide the ability to travel in the most difficult conditions, make excellent use of this opportunity.

Speaking about the torsion beam, which occupies a special place in the suspension design, it must be said that its guiding device is considered to be a pair trailing arms, which are attached to the body on one side and to the wheel hubs on the other. The beam itself has a U-shaped cross-section, so you can count on maximum rigidity and strength. The bending strength will be stronger than the torsional strength. Therefore, the wheels can move vertically, independently of each other.

A short video explaining what a torsion bar suspension is:

A car suspension is a system that connects the wheels to the frame or supporting body of the car. It consists of elastic elements, units that guide the movement of the wheels (hinge-mounted levers that hold wheel hubs, or one-piece axles with rods) and shock absorbers. Depending on the elastic elements used, there are spring, spring, pneumatic and torsion bar suspension. Let's look at the operating principle of the latter in more detail.

Sometimes one suspension element takes on the functions of several devices, for example, the good old multi-leaf springs are at the same time an elastic and guiding element, and due to the friction of the sheets against each other, they even have a slightly shock-absorbing component.

However, in the chassis modern cars each of these functions is usually performed various nodes. But today we are interested in torsion bar suspension, its pros and cons. The operating principle of such a suspension was applied in the thirties of the last century. It was first implemented at the same time in the chassis of a Citroen car. After some time, this design became of interest to German automakers, so the principle of its operation was used to create the chassis of the Volkswagen Beetle. Torsion bars were once used in the suspension of the heavy Soviet KV tank and the German Panther. From domestic cars The legendary Zaporozhets, the ZIL truck, and the all-wheel drive LUAZ subcompact, nicknamed by car enthusiasts the Lunokhod, had a torsion bar suspension.

What type of suspension is called torsion bar?

Torsion(from French torsion- twisting, torsion) - a rod that works to twist and performs the functions of a spring. It allows high torsional stresses and significant twist angles of several tens of degrees. Made from spring steel with subsequent heat treatment.

Torsion bar suspension is chassis car, which is equipped with torsion bars as elastic elements.

Torsion bars are more often rods of round and square cross-section or, which is less common, made up of several plates of spring steel, like springs, but working to twist. Round rods at one end usually have a splined knurl for attaching them to levers, and for attaching to a supporting element (frame or body), the other end has either splines or a profile that differs from the round one. For more reliable fastening, the spline knurled section is usually made with a larger diameter than that of the main rod. Torsion bar suspension can be independent or semi-independent, as in the photo. Independent torsion bar suspension is most often used at the front of the car. Semi-independent torsion bar suspension (torsion beam) is often found in the rear of front-wheel drive vehicles. The operating principle of a torsion bar is the same as a spring. Only the spring stores energy by compressing, and the torsion bar by twisting.

Types of suspension

Advantages of a torsion bar in suspension

Torsion bars in independent suspension have the following advantages compared to other elastic elements:

• Greater running smoothness achieved thanks to best characteristics deformation. This ensures a nonlinear increase in rigidity, depending on the amount of twist, that is, at the end of the stroke the suspension becomes stiffer, which softens its impact on the bump stop.
• Simplicity of design.
• Compactness.
• Possibility of suspension repair without zip ties or other special tools.
• Availability of adjustment of suspension stiffness and ground clearance.

The torsion beam in the chassis of the car is used in semi-independent rear suspension, which also has several advantages:

Disadvantages of torsion bars

To the disadvantages of the rear torsion beams imported cars Perhaps only needle bearings in their attachment to load-bearing elements can be attributed, which from time to time fail, since they are difficult to protect from corrosion under the bottom of the body. It is pleasant to note that the rear beam of our VAZ 2108, attached to the body through rubber-metal hinges, is free from this drawback.