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What is a spar in the car

June 16, 2020

The term "spar" from time to time occurs when talking to employees of car repair shops. What is a spar in the car and where it can "go"? In the car this is the main structural element, running along its entire length. The two spars are connected to the frame by means of crossbars. The body and other parts of the car are attached to the frame. In other words, the spar is a metal pipe, which has a rectangular cross section, most often it is a paired part - for the back and front.

Depending on the car model, it can be implemented the idea of ​​installing side members at the rear and front, or run along the entire body.

construction

The design consists of the most longitudinal beams and jumpers, installed between them. It resembles a ladder, accordingly, in the circles of motorists, this frame is often called a staircase.

car frame

The appearance resembles a mesh box. It is an item of extraordinary impact strength, able to withstand enormous weight - it can't be otherwise, after all, it has the pressure of the whole car, together with luggage and passengers. A variant of the design in the form of the letter "P" laid sideways is more common in heavy SUVs and trucks. Non-stair spars are usually installed on cars.

The term itself came from the French word "longer" - a verb, denoting movement along. In accordance, "Spar" can be literally translated as the movement along the length of the car structure. The same term is used to name the relevant part of the aircraft, carriage, ship, bridge.

Car frame

Why do you need a spar?

The rear and front side members are the power unit of any system, where it is installed. In trucks and heavy SUVs, it becomes part of the frame, in a frameless car it is designed to strengthen the bottom of the body. Engine weight, body, driver with passengers, heavy luggage in total can be colossal, and all of them can withstand the spar.

Another feature of this element is the shock absorbers for the front of the car. If the body is too stiff, the blow to them cannot be completely absorbed and is transferred to passengers. Longerons are involved in the absorption of deformation distortions, that makes part of the body, where passengers are accommodated, slightly deformed.

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The design of the front of the car

To ensure this function in the body at the rear and front created deformable zones, in which the longitudinal force structure is weakened. Weakening of spars can occur in several ways:

  • reducing the wall thickness;
  • reducing the cross section;
  • holes in the parts, subjected to minimal loads;
  • creating folds, providing removal of a detail in a peculiar accordion at road accident. In frontal or rear impact, these places are destroyed, but the absorption of the maximum impact energy is achieved with a decrease in the impact force directed to the cabin.

What are spars

The position of such parts in the car is several options, relative to the body and each other, depending on the model of the machine itself:

  1. parallel or at an angle in the horizontal direction;
  2. vertically or horizontally, in a bent form.

The first option is used on trucks, the next three are used on frame SUVs. Placing at an angle to each other makes it possible to turn the wheels to the maximum angle. When the elements are curved in the vertical direction, the center of gravity of the car is reduced and the floor in the cabin is at a lower level. With horizontally curved elements, the floor level also decreases, and increases the passive safety of the machine in the event of a side impact.

Scheme of the spar

Crossbeams, which are in connection with the longitudinal profile, provide the construction of the foundation of the machine great rigidity. They are rectilinear or in the form of the letter K or X.. The crossbars themselves are a curved metal profile. Rivets are used to connect them in trucks, in cars crossbeams are welded. Brackets are used to attach car parts to the frame.

spar malfunctions

What is a spar?? This is a heavily loaded element of the car, which accounts for the weight of the body, engine and all, located in the cabin and trunk of the car.

Under such influence, it can deform over time. With prolonged intensive use, it may crack, due to which the most important characteristics of the car can be seriously changed. Machine parts may change position. This applies to the engine, suspension, wing, which due to changes in the parameters of the spar change their position. In case of an accident, the change in the geometry of the spar is a frequent case. At the same time the body design of a car is broken loses integrity, its dimensions.

Processing of thresholds of the car inside and outside

At deformation of a spar due to road accident the geometry of a suspension bracket can be broken, cracks appear outside the car, non-removable. Steering is violated, tire wear increases.

spar deformation

At emergence of such signs it is possible to speak with sufficient confidence about deformations of a spar, therefore specialists in car repair shops, inspecting the car after a collision, be sure to check the condition and position of this part.

The spar can burst completely with a colossal shock load, and this leads to the complete destruction of the body structure. That is why it is so important to check his condition after even a minor accident.

repair

In the vast majority of cases, the repair concerns the front side members, the back is deformed less often. A special caroliner stand is required to correct the deformation. It is necessary to disassemble a significant part of the car. But it is very difficult for even the most experienced masters to perform the task of correcting a deformed spar. Substitute, as well as the repair of the spar - the procedure lasted, very difficult and expensive.

When the main parts of this part remain in normal condition, partial replacement can be performed by gas welding. But do not expect, that welding of the damaged spar will restore in it factory qualities. Its strength will decrease significantly, in accordance, it will perform its important functions much worse. With a stair frame, it is easier to replace the spar. But if this detail went badly in the bearing body of the car, replacement of the spar becomes meaningless and often have to change the body completely.