In the designs of modern independent suspensions, along with a spring or a pneumatic balloon, a torsion bar (torsion, in translation 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 ride comfort and compactness of the suspension. However, her significant disadvantages in the form of worse handling and rollback 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 in use 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 the torsion bar suspension was primarily due to good performance smooth running and simplicity of design.

What is a torsion bar?

The torsion 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 - consisting of several layers, working together in torsion.

Elastic torsion bar suspension element with mountings

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

Round torsion shafts

The steel alloy from which the torsion bar is made possesses high performance elasticity and endurance, is able to withstand prolonged loads without deterioration of its properties. Shaft length and thickness also affect suspension performance and softness. 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 the torsion bar suspension

The torsion bar suspension works in the same way as a spring, leaf spring or air suspension. A steel rod - torsion bar acts as a spring element. When the suspension is in operation, a force is transmitted to the torsion bar from the support arm, which makes the rod twist up to a certain limit. After that elastic element returns to its original state, leveling and position of the lever.

Types of torsion suspensions

Front independent torsion bar suspension on wishbones

The device and principle of operation of the torsion bar suspension

Front torsion bar suspension with wishbones (one or two, depending on the design) consists of the following elements:

• A longitudinally positioned torsion bar that works in torsion and replaces the spring.
• The upper or lower arm that receives the main load, through which the force is transferred to the torsion bar.
• Damping element - performing the function of damping vibrations.
• , compensating for body roll when driving.

Independent double wishbone front torsion bar suspension Toyota Hilux Surf

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

Rear independent suspension with transverse torsion bars

In the designs of the rear suspensions with a longitudinal arrangement of the levers, the 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 transversely.

Rear suspension with transverse torsion bars

A feature of the elastic elements of the rear suspension was their location - one was behind the other, which constructively attracted a difference in the wheelbase on the sides of the car (one of the wheels was closer to the front by a few centimeters). The handling and stability of the car 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 bar

The semi-independent U-shaped torsion beam, which has an integrated elastic bar, becomes more bending strength. At the same time, it allows the wheels of one axle to move slightly relative to each other when driving over irregularities. This improves the handling and stability of the vehicle. This suspension is used on rear axle most budget front wheel drive vehicles.

Why do you need it?

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

Recall that a car needs a suspension to provide shock absorption when the wheels of the car and its supporting system are connected. The suspension performs one more important function: it reduces the load on the wheels from the side road surface, stabilizing the position of the body while driving.

A little background

In the first half of the last century, around the 30s, the car 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 for the modern torsion bar suspension. Later this design was improved by the scientist Ledwink from Czechoslovakia, and then it was installed on Tatra vehicles.

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 under the name "KDF-Wagen". Further, during the Second World War, this suspension was used in the construction of tanks and other military equipment... V post-war years Renault and Citroen are interested in torsion bars. However, soon, despite the ease of operation, the production of torsion bars became much more difficult, so it was abandoned. Currently, torsion bar suspension is widely used in trucks and on SUVs of 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 on the chassis, and the other - on 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 undergo 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 cars. On trucks, the beam has a longitudinal position. 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, for reducing the oscillations of the steered wheels. One

In some cases, the torsion bar suspension also performs the function of automatic leveling using the engine, which, in turn, tightens the torsion shafts to give additional rigidity. A similar design can be used when changing a wheel. While all three wheels raise the car, the fourth can be replaced without using a jack.

Advantages

Torsion bar suspension has several advantages over other types. For example, the service life of such a structure is much longer, moreover, the height adjustment is easier. This suspension is more compact and easier to maintain, which is the main advantage. When loose, it can be repaired with a standard wrench, which is not the case with the spring suspension.

The torsion bar is a metal elastic element that works for twisting. As a rule, it is a metal rod of circular cross-section with spline connection at the ends. A torsion bar can consist of a set of plates, rods, a beam 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 end to the guide element - to the lever. When the wheels move, the torsion bar is twisted, thereby achieving an elastic connection between the wheel and the body. A feature of torsion bars is rotation only in 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 different types independent suspensions: on double wishbones, on trailing arms, with connected trailing arms (torsion beam).

In a torsion bar suspension on double wishbones, the torsion bars are located parallel to the body, due to which their length and, accordingly, elastic properties can be adjusted in a wide range. One end of the torsion bar is attached to the lower transverse arm (less often to the upper arm), the other end to the vehicle 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 the torsion bar suspension on the 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 small passenger car models. A special place in the design of torsion suspensions is occupied by the so-called. torsion beam or suspension with associated trailing arms. The guiding device of this suspension is two trailing 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 stiffness and low torsional stiffness. This property allows the wheels to move up and down independently of each other. The torsion beam is currently widely used as the rear suspension in front-wheel drive small and medium-sized vehicles. Due to its design, the suspension with a torsion bar occupies an intermediate position between the dependent and independent types of suspensions, therefore its other name is semi-independent suspension.

History of appearance

Torsion bar suspension began to be used in the mid-1930s on cars of the French Citroen brands... 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 the torsion bar suspension was primarily due to its good ride quality and simplicity of design.

Types of torsion 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 for torsion and replaces the spring. The upper or lower arm that receives the main load, through which the force is transferred to the torsion bar. Damping element - a shock absorber that damping vibrations. Anti-roll bar, which compensates for body roll when driving. The compactness of the front wishbone torsion bar suspension allows efficient use of free space. For example, for the installation of massive wheel drives. In this regard, torsion bars have become widespread in the production of frame off-road vehicles that combine increased cross-country ability with a soft suspension. For example, Toyota Land Cruiser 100 (torsion bar mount to the lower arm) and Toyota Hilux Surf (torsion bar on the upper arm). Torsion bars are also used on the front axle of commercial vehicles.

Rear independent suspension with transverse torsion bars

In the designs of the rear suspensions with a longitudinal arrangement of the levers, the 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 ones. A feature of the elastic elements of the rear suspension was their location - one was behind the other, which constructively attracted a difference in the wheelbase on the sides of the car (one of the wheels was closer to the front by a few centimeters). The handling and stability of the car left much to be desired, however, 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.

Semi-independent rear torsion beam

The semi-independent U-shaped torsion beam, which has an integrated elastic bar, becomes more bending strength. At the same time, it allows the wheels of one axle to move slightly relative to each other when driving over irregularities. This improves the handling and stability of the vehicle. This suspension is used on the rear axle of most budget front wheel drive vehicles.

Benefits of torsion bar suspension

✔ High smoothness. ✔ Compact and lightweight. ✔ High maintainability. ✔ Simplicity and reliability of the design.

Disadvantages of torsion bar suspension

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

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Modern cars are very different from those that were common in the days of our parents' youth. However, the main structural elements have survived. They have only been improved to the point where they are ready for normal day-to-day use. Suspension is an example.

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

Torsion bar suspension on a real car

General terms

Torsion bar suspension is a 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 that is fixed completely perpendicularly and is connected to the axle. The suspension of the type in question is made of steel that has been pre-treated in the appropriate temperature conditions... Due 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 in which a significant load on the chassis is provided. And here cars, in general, they use the transverse arrangement of this suspension, and even on the rear wheel drive.

There is such a suspension on other vehicles.

But, in both cases, such a suspension helps to ensure a fairly smooth movement, as well as to regulate the roll when cornering. This ensures the maximum value of vibration damping for both the wheels and the body. In addition, the vibration of the wheels is reduced, which are in in this case manageable.

Some car models use a torsion bar suspension in order to carry out automatic leveling by means of the motor. He, as it were, pulls together the beams, giving additional rigidity. The specific efficiency is determined by the speed of movement and the condition of the road.

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

The advantage of torsion bar suspension

As with any technology, the torsion bar suspension has its advantages. We say that the operation of cars with this type of suspension is one of the longest. This is a result of the way the torsion bar suspension works.

Height adjustment

Plus, you can make height adjustments very easily. And the compactness in width will do a good job, as automotive manufacturers, and those who will be engaged in direct maintenance of the car.

Save space

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

Schematic representation of a torsion bar suspension

In a situation where such a suspension is loose, then adjusting it can be very simple. For this, a conventional wrench is used. You only need to get under the car to tighten the necessary bolts. But, here you need to remember that overtightening of the bolts is fraught with a very rigid course of the car in the future. This is the main pros and cons of the torsion bar suspension.

But what is a torsion bar?

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

Basically, this is a metal rod that has a circular cross-section with a special splined-type connection at its ends. In some cases, a torsion bar can 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 itself looks like

The appearance of the torsion bar from the car Mitsubishi Pajero

Highly important feature The torsion bar can be considered 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 great 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 a pair trailing arms, which are attached to the body on one side and to the wheel hubs on the other. The beam itself is U-shaped, so you can count on maximum rigidity and strength. Flexural strength will be stronger than torsional strength. Therefore, the wheels can move vertically, independently of each other.

A short video on what a torsion bar suspension is:

Automotive suspension is a system that connects the wheels to the frame or monocoque body of a vehicle. It consists of elastic elements, nodes guiding the wheel travel (hinged levers that hold wheel hubs, or one-piece bridges with rods) and shock absorbers. Depending on the elastic elements used, there are leaf, spring, air and torsion bar suspension. Let's consider the principle of operation of the latter in more detail.

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

However, in the undercarriage modern cars each of these functions is usually performed by various nodes... But today we are interested in the torsion bar suspension, its pros and cons. The principle of operation 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 interested 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 four-wheel drive small car LUAZ, nicknamed the lunar rover by motorists, had a torsion bar suspension.

What kind of suspension is called a torsion bar

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

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

Torsion bars are often rod round and square, or, which is less common, - recruited from several plates of spring steel, like springs, but working for twisting. Round rods at one end usually have a spline knurling for attaching them to the levers, and for attaching to a supporting element (frame or body), the other end has either slots or a profile that differs from the round one. The spline knurled area is usually made larger in diameter than the main rod for more secure attachment. The torsion bar suspension is independent or semi-independent, as in the photo. An independent torsion bar suspension is more commonly used at the front of a vehicle. Semi-independent torsion bar suspension (torsion beam) is often found in the rear of front-wheel drive vehicles. The principle of operation of a torsion bar is the same as that of springs. Only the spring stores energy by compressing, and the torsion bar is twisting.

Suspension types

The advantages of a torsion bar in suspension

Torsion bars in independent suspension have the following advantages in comparison with other elastic elements:

• Greater smoothness thanks to better performance deformation. This provides a non-linear increase in stiffness, depending on the amount of twisting, that is, at the end of the stroke, the suspension becomes stiffer, which softens its impact on the bumper.
• Simplicity of design.
• Compactness.
• The possibility of repairing the suspension without ties and other special tools.
• Availability of adjustment of suspension stiffness and ground clearance.

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

Disadvantages of torsion bars

To the disadvantages of the rear torsion beams imported cars can be attributed, perhaps, only the needle bearings in their fastening to the load-bearing elements, which from time to time fail, since it is difficult to protect them 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 devoid of this drawback.