What is a car frame and what types are there

One of the most important elements of a vehicle is the support system. It is she who makes it possible to make a single whole out of all the components of the machine. Previously, all vehicles had a frame structure. However, over time, it was supplanted by other types, including a monocoque body, which is used in almost all passenger cars. Nevertheless, the frame bearing part is still used - on SUVs and trucks.

What is a car frame: purpose, pros and cons

The frame of the car is a beam structure that acts as the basis for fastening all components and assemblies, such as the power plant, transmission elements, chassis, and so on. The body with this design of the supporting system provides space for passengers and luggage, and also performs a decorative function.

The use of the frame makes it possible to give the bearing part high strength. Therefore, it is used in trucks and SUVs. It also makes it possible to maximize the unification of units and mechanisms between models of different classes.

Previously, car manufacturers produced car chassis with basic parts (frame, engine, transmission, etc.), where various types of bodies were "stretched".

The frame in the car acts as a "skeleton". She perceives all external and internal loads when the car is moving and even when it is parked. In view of this, a number of requirements are imposed on the car frame:

• sufficient strength and rigidity;
• small weight;
• the correct shape, which will contribute to the rational operation of all elements of the car.

The frame bearing part has a number of advantages. So, thanks to her, it becomes much easier to assemble a car and repair it in the future. The main difference between the frame structure and the body structure is that any breakdown can be easily eliminated thanks to a good specialist and materials. Another important advantage: driving on bad roads will not be fraught with distortions of the body (door openings, pillars, etc.).

Along with this, there are also disadvantages. The first is a significant increase in vehicle weight due to the presence of a separate frame and body. Accordingly, the fuel consumption will also be higher. Another disadvantage is that additional space is needed to place the side members under the body, which complicates getting into the car and takes up a significant part of the passenger compartment.

A decrease in passive safety is also noted, since there is a possibility of displacement of the frame relative to the body in the event of an impact. Therefore, the load-bearing body is an integral part of a passenger car. At the same time, the frame structure copes well with the harsh conditions in which trucks and SUVs drive.

Types of frames

Frames are divided into several types, differing in design features:

• Spar;
• spinal ridges;
• spatial.

Some species have subspecies. Combined types are also distinguished, combining components of different types of frames in the design.

Spar frame

This is the most common type. The frame design includes two power longitudinal beams, which are called spars. They stretch along the body and are connected by means of cross members. The beams are made of steel. In order to increase the twisting performance, various types of cross-sectional profiles can be used.

The spars are not necessarily straight - sometimes they have both vertical and horizontal bends. They can be located both parallel to the horizontal plane and at a certain angle, which is inherent in SUVs. It is also possible to have a different arrangement of cross members, due to which the side members are connected. It is by far the most popular frame construction used in most trucks and SUVs.

This frame is great for driving on rough roads. It also simplifies vehicle repair and assembly. The disadvantages are that the spars take up a considerable part of the cabin and complicate the landing process somewhat.

Spar X-shaped

The X-shaped frame is one of the types of spar. The peculiarity of its design is that the spars in front and behind are divorced, and in the center they are maximally reduced. This type looks like a beech "X", which is the reason for its name.

Peripheral

It is a type of spar frames. This type began to be actively used on large European-made passenger cars and "dreadnoughts" from the United States in the 60s. In such frames, the spars are located so wide that during the installation of the body they are located at the thresholds. This allows the floor level to be significantly lowered while at the same time reducing the immediate height of the machine.

An important advantage of such a machine is its maximum adaptability to side impacts. However, there is a significant disadvantage - the frame cannot withstand significant loads, so the car body must have the necessary strength and rigidity.

Spine frame

This type of frames was developed by representatives of the Tatra company and was mainly used for machines of its production. The main carrier is a pipe connecting the engine at the front to the transmission elements that are located inside it. In fact, the pipe acts as a single crankcase for the gearbox, transfer case and drive shafts. The torque from the engine to the transmission is supplied by a shaft placed in the tube. Moreover, this shaft is not a cardan shaft, which ensures greater reliability.

This frame design, in combination with independent wheel suspension, provides very large travel, which makes it indispensable in special vehicles.

The advantage of the backbone frame is also that it has a very high torsional rigidity, and the transmission elements are reliably protected from external influences. But due to the fact that certain mechanisms are located inside the frame structure, repair work becomes noticeably more complicated.

Vilchato-ridge

Fork-ridge type of frames is also the development of "Tatra". In this version, the engine is not attached to the transmission pipe, but on a special side-member fork. This is done in order to reduce the level of transmitted vibrations from the operating internal combustion engine to the frame and, therefore, to the car body. However, today fork-spine frames are no longer used in the automotive industry.

Spatial frame

The most complex type of frame construction used for sports cars. This structure is a frame based on thin alloy pipes and has very high stiffness and strength. In the automotive industry, these frames have been supplanted by monocoque, however, similar designs are used in the creation of buses.

Bearing base

The supporting base is something between the body and the frame structure. Spars are also used here, but they are united by the bottom, and not by the cross members. The most massive and popular owner of the bearing bottom is the Volkswagen Beetle, in which the body is attached to the flat floor panel by means of bolts. Another mass-production vehicle, Renault 4CV, has a similar design.

The load-bearing bottom is characterized by high manufacturability and is used in large-scale production. This design allows the floor and center of gravity of the vehicle to be kept low enough.

The frame bearing part of the car has a number of advantages and features that make it indispensable for trucks and SUVs. And although the frame is used purely for specific types of cars, some of its structural elements are used very widely, as they allow the supporting bodies to be made more rigid. Almost any passenger car is equipped with reinforcing spars or subframes.