Long-term studies have shown that during the movement of the car, uncontrolled forces act on the body, proportional to the mass of the car at the moment and its speed, which act in three directions - vertical, horizontal and frontal - and cause such types of deformation of the body elements as bending, compression, twisting. task repair work is the restoration of the designed endurance of the body components according to the manufacturer's instructions. The technology of repair work must be such that the endurance of the repaired parts corresponds to the non-repaired parts of the car.
For cars with a load-bearing body, the functions of the frame are either performed by the body itself, or the frame (or subframes replacing it) are structurally integrated with the body and cannot be separated from it without violating structural integrity. Typically, the body is attached to the frame using bolt-on brackets with thick rubber pads to reduce vibration.
All units are attached to the frame of the car: engine, transmission, axles, suspensions. Together they form the chassis. The frame chassis is a complete structure that can exist and move separately from the body.
At present, frame chassis are used mainly on tractors and trucks, but in the past, many passenger cars mobiles also had a frame chassis. “Rigid” SUVs often have a separate frame.
The following types of frames are distinguished: spar, peripheral, spinal, forked-spinal, bearing base, lattice (they are also tubular).
Spar frame with X-shaped crossbar
Spar frames consist of two longitudinal spars and several crossbars, called "traverses", as well as mounts and brackets for mounting the body and units.
The shape and design of the spars and crossbars can be different; distinguish between tubular, K-shaped and X-shaped crossbars. Spars, as a rule, in the section are a channel, and the length of the section usually changes: in the most loaded areas, the section height is often increased. They can be located both in parallel and at some angle relative to each other.
Peripheral frames
Sometimes considered as a kind of spar. In such a frame, the distance between the spars in the central part is increased so much that when the body is installed, they are directly behind the door thresholds. Since the frame is weakened at the transition points from the usual distance between the side members to the increased one, special box-shaped reinforcements are added in such places, in English-speaking countries called the term torque box.
This solution allows you to significantly lower the floor of the body, placing it completely between the spars, and therefore reduce the overall height of the car. Therefore, peripheral frames have been widely used on American passenger cars since the sixties. In addition, the location of the spars directly behind the thresholds of the body is very conducive to improving the safety of the car in a side impact.
Spinal frames
chief constructive element such a frame is a central transmission pipe, rigidly connecting the crankcases of the engine and power transmission units - clutches, gearboxes, transfer box, the main gear (or main gears - on multi-axle vehicles), inside which there is a thin shaft that replaces the cardan shaft in this design. Requires independent suspension on all wheels.
The advantage of such a scheme is high torsional rigidity; in addition, it allows you to easily create modifications to cars with a different number of drive axles. However, the repair of the units enclosed in the frame is extremely difficult. Therefore, this type of frame is used very rarely, and on passenger cars it is completely out of use.
Fork-spine frames
A kind of spinal frame, in which the front, sometimes the rear parts are forks formed by two spars and used to mount the engine and units.
Unlike the backbone frame, the crankcases of the power transmission units are usually (but not always) made separately, if necessary, it uses a conventional cardan shaft. Such a frame was used, among others, by Tatra executive cars from T77 to T613.
X-shaped frames are often referred to the same type, which are considered by some sources as a kind of spar frames. Their spars in the central part are very close to each other and form a closed tubular profile. This frame has been used for Soviet cars"Seagull" GAZ-13 and GAZ-14 of the highest class.
load-bearing base
This frame is integrated with the body floor for increased rigidity.
Among others, the Volkswagen Beetle and the LAZ-695 bus had such a design. At present, this scheme is considered quite promising due to the ability to build the most different cars like on the platform.
lattice
Also called tubular (tubular frame) or spatial (spaceframe).
Lattice frames are in the form of an iso-truss having a very high torsional rigidity-to-weight ratio (i.e., they are light and very torsional-strength).
Such frames are used either on sports and racing cars, for which low weight is important with high strength, or on buses, for whose angular bodies it is very convenient and technologically advanced in production.
When it comes to repair technology, the question often arises of how to repair or change an element that is load-bearing in its design features. For example, consider the frontal deformation of the front of the car at an angle, in which the front panel, hood, fender, mudguard and side member are deformed. Of these, in this node, two removable elements can be distinguished - a wing and a hood - and three or more welded ones - a radiator frame, a mudguard, a spar. During the repair work of deformed elements, it is necessary to ensure the functions laid down by the manufacturer (symmetry of the structure, symmetry of the shape of the body and its elements, passenger safety while driving, etc.).
Therefore, if we accept the repair of the mudguard and fender, then the hood, radiator frame and spars must be replaced. When replacing the hood, it is possible to control the repaired surface of the wing at the junction with the hood, control the location of the radiator frame when replacing it, and adjoin the repaired mudguard to it. When replacing the radiator frame, it is possible to control the geometry of the hood opening, the correct adjoining of the mudguard to the upper part.
When replacing the spar, it is necessary to ensure the strength of this unit, weakened by the repair of the mudguard and wing. In this case, it must be taken into account that, conditionally, repairs without heating and welding will be applied to the wing and mudguard. If heating is applied to one of the repaired elements to shrink the metal or weld a gap or technological cut, then the other element must be replaced with a new one. In this case, it is most expedient from an economic point of view to replace the wing. If, however, a decision is made to repair the spar assembly, that is, the U-shaped spar itself with slight heating, then the amplifier must be replaced when editing, be it a separate amplifier, which is an amplifier mudguard or other element.
It must also be remembered that although the manufacturer designed the structural endurance of body elements for a safety factor n = 1.3–1.5, and for the edges of the body, which are subject to the combined action of turbulent forces formed by the gearbox and wheels during movement, the safety factor is even 1.5–2.0, without proper equipment, technological maps and load distribution diagrams during an accident, we cannot determine how the repair factor will affect the safety of passengers during deformation in the future.
Considering that the technology of repair work should bring the endurance of the repaired parts of the car in line with the non-repaired ones, ideal option repair of this unit will be the replacement of all elements that cannot be repaired without the use of heating or welding of technological cuts.
An example of repairing a side member on a frame car
The right side member under the floor of the passenger seat is struck through corrosion to such an extent that the arm brackets front axle are not only unable to perform their functions, but also come off.
For repairs, a used spar with a mudguard was bought, from which the necessary parts were cut.
In order to securely place the support under the threshold, it had to be replaced, as well as partially replace the floor.
After that, the front axle levers are removed, the damaged part of the side member is cut out and replaced. The work is not easy, because the load distribution cutouts are made difficult, sometimes it is difficult to access them for welding, and it is necessary to apply seams on both sides.
The photo shows a floor reinforcement, on which an overlay is welded, welded to the side member.
We weld the repair parts to the floor, protect the seams with sealant from all sides.
We apply an anti-gravel coating to all repaired places, carry out internal anti-corrosion treatment of the threshold and side member and get the result of the repair.
If the result of a collision with a car is a significant deformation, it is first necessary to remove the mechanical units - this is the only way to carefully straighten the folds and replace parts that cannot be repaired. In addition, this will remove residual stresses that may arise and remain after straightening. When the car is moving, residual stresses can cause stresses in the mountings of shock absorbers and bushings, and sometimes breaks.
But in some cases, pre-straightening the body with installed mechanical units can facilitate access to the units to be removed, for example, to the propulsion unit in cars with front-wheel drive, to the front or rear axle. In this case, care must be taken to replace the mounting bolts and shock absorbers. This operation is performed on the stand.
If a blow to the front or rear half-axle caused deformation of the base of the body, it is also possible to straighten the body by fixing (hooking) the stretching mechanism for mechanical units, such as wheel rims or suspension arms that have received deformation. Editing is done in the direction directly opposite to the impact. Performing such an operation is possible only if the blow fell directly on the front or rear half-axle, and its replacement is necessary.
Also be sure to replace the ball joints and steering rods. Straightening with a jack or other hydraulic mechanism is used to restore the shape or straighten a deformed part. However, when starting work, one should not forget that with a very sharp editing of a body part, deformation of the neighboring zone may occur. Therefore, when stretching, i.e., simultaneously with the action of the jack, it is recommended to accompany the restoration of the linearity of the body by tapping out the folds. And after drawing out with a jack, it is necessary to remove all internal stresses by tapping (using a straightening hammer) the entire area that has been straightened.
In order to be sure that there will not subsequently be a reverse movement of the straightened sections of the body due to residual stresses, the surface is tapped through the wooden lining in the direction of impact. If at the same time the straightened body does not change its shape, then the editing operation was performed correctly. Otherwise, you should edit again until the geometry is within the tolerances specified by the vehicle manufacturer.
If the car has received a side impact, this causes deformation of the base of the body, accompanied by a decrease in the length of the body on the side of the damaged surface, which is easy to determine. When editing on the stand, the performer must take this circumstance into account. In practice, straightening is carried out by stretching in two directions simultaneously: lateral and longitudinal, which makes it possible to restore the original geometry of the body base.
An example of the restoration of the side surface is the alignment of the middle rack, which is wrapped with a pull chain. To protect the rack from damage and evenly distribute the force between the rack and the chain, a wooden plank is laid.
Longitudinal stretching, performed simultaneously with lateral stretching, can be performed different ways. If the deformation is concentrated in the lower part of the body, the base is straightened directly, fixing the clamps to the flanging of the thresholds. The jack is placed between two clamps and under pressure moves them in the longitudinal direction as the simultaneous lateral stretching is carried out. If the deformation is concentrated in the upper part of the body, stretching is carried out in the longitudinal direction from the front and rear parts of the body.
Work on straightening and checking new spars must necessarily be carried out on precision equipment, which is available only in workshops.
In any case, geometry diagnostics are best done on good equipment, the choice of which will be discussed in the next issue.
In preparing the article, materials from open sources were used in accordance with the GNU Free Documentation License.
Every year the design of cars changes, according to demand. If earlier almost all so-called SUVs were built on a frame, today many mastodons are losing it. But there is still gunpowder in the flasks and frame SUVs on the market
In our material, we will talk about endangered frame SUVs that can still be purchased in Ukraine. But first, let's talk about what a frame is and what its role is.
What is a frame
If you do not get into technical details, then frame body- This is a body that is attached to the chassis of the car using a frame. That is, a frame machine is considered to be one in which the frame carries the chassis (engine, transmission, transfer case, etc.), and the body is separately attached to this entire structure from above.
There is also such a thing as an integrated frame. In this case, the frame repeats the usual design, but is physically inseparable from the body, that is, it has a non-separable welded connection with it. A body with an integrated frame differs from a conventional carrier in that the integrated frame has full-fledged side members extending from the front bumper to the rear. Compared to a traditional frame structure, such a body absorbs vibrations worse, it is more difficult to restore it after an accident. But passive safety better - you can form deformation zones. Compared with a load-bearing body, the integrated frame makes it more painful for the chassis to perceive the loads that arise when transporting goods and driving off-road.
Many auto giants are abandoning the traditional frame (sometimes in favor of an integrated one) in order to reduce material costs, although the frame is more profitable when creating new / updated models - it can cling to a body of almost any shape. There are other reasons that are gradually sending the frame into retirement. But first, about the advantages of classic frame cars.
pros
- running frame cars are considered more durable
- ideal for towing and operation in difficult conditions
- frame cars easier to recover after an accident
- when driving off-road, the loads are evenly distributed on the frame and body
- frame SUVs are easy to tune (wheels of increased radius, "lifting")
Minuses
- frame significantly increases the weight of the car
- an increase in mass means an increase in fuel consumption
- in terms of handling, frame cars lose cars with a monocoque body
- often a low level of passive safety, due to the likelihood of body displacement relative to the frame and the difficulty of determining deformation zones
- the frame reduces the useful volume of the cabin
UAZ
In the segment of the most affordable SUVs, the choice is small. But he is.
The cheapest model with a frame is UAZ Hunter, which costs from 125,900 hryvnia to 163,740 hryvnia. Hunter began production in 2003, but we all know that in fact it is a converted version of the car back in 1972. We also recall that the Volga (GAZ-21) formed the basis of the UAZ. Simply put, the modern Hunter is a Russian interpretation of the model of the past - like Mercedes G-class.
The second frame UAZ - Patriot. This is a more modern model, which is an improved version of the UAZ-3160, the body of which was developed at AvtoVAZ in the 1980s. Outwardly, it also looks more modern than Hunter, and in size and clearance is not inferior to the bulky Land cruiser from . In Ukraine, the Patriot is available as a traditional SUV (from UAH 175,000) and as a pickup truck (from UAH 176,200). There are versions with air conditioning, ABS and other benefits of civilization. Motors - petrol and diesel.
Great Wall
Brand introduced in Ukraine Great Wall is one of those that offer a wide range of frame SUVs. To date, there are three, including one pickup truck.
Wingle 5. Frame pickup truck from China, which is even cheaper than UAZ. At the moment, at a promotional price, it can be purchased for 122,400 UAH. (in the basic version). True, this is if we are talking about a mono-drive performance. The all-wheel drive version will cost at least UAH 152,000. (for the car of 2011 of release). The same car of 2012 costs UAH 169,000. The car is the result of independent research and development by Great Wall. It is equipped with two engines: gasoline manufactured by Mitsubishi Corp. and diesel using Bosch technologies.
Haval H3. It costs from 147 124 UAH. (at a promotional price - UAH 141,900). Equipped with a 2.0 liter engine ( Mitsubishi technology), two airbags, ABS+EBD systems and complies with European safety standards (4 stars E-NCAP).
Haval H5. Price - from 187 900 UAH. HAVAL H5 is equipped with diesel engine, developed by the German company BOSCH together with GREAT WALL MOTORS specialists, uses a Common Rail fuel injection system. It is completed with modern 6-tbsp. mechanical or 5-st. automatic transmissions. Has a pluggable four-wheel drive.
ssangyong
Like the Great Wall, the Korean brand has a whole army of frame SUVs in its model range (with the exception of crossover Korando). Moreover, even the flagship Rexton in the last incarnation has not lost the frame structure. For the modern automotive industry, an unprecedented rarity. In general, SsangYong is represented in Ukraine today by six "frames".
Kyron. A very popular SUV in Ukraine, which is due to its low cost (at the moment - from 178,000 UAH for a gasoline version in the entry-level configuration).
At one price (UAH 196,900) are diesel Kyron and Actyon in the initial configuration. It should be noted that Kyron is the owner of the title "Leader of Sales - SUV" in the national award "Autorating" in 2010.
Actyon Sports(4-seater pickup truck) is available in one configuration (with diesel and automatic) - for 212,900 UAH. His updated version also available for purchase, but there is currently no price on the importer's website. The presentation said that Actyon Sports was created specifically for young, active and practical people who like to be in the spotlight.
The flagship Rexton model is available both in a new look (from UAH 245,000) and before restyling (from UAH 224,000). Engines - petrol and diesel.
Nissan
Today, Nissan sells four frame SUVs in Ukraine, including one pickup truck.
The most controversial of them is Patrol latest generation. There is still controversy over its design. Some consider it a frame, while others argue that there is no frame there at all. In fact, both are right. After all, in fact, this SUV is equipped with independent suspension all wheels and a body with an integrated frame. That is, he retained the frame, but now it is integrated into the power structure of the body and has programmed deformation zones in front and behind (remember the passive safety of frame SUVs). A similar design and Mitsubishi Pajero Wagon, so these cars cannot be considered real frame SUVs. More precisely, incorrectly.
NP300. Affordable and highly practical 4-door pickup, only available with a 2.5 liter diesel engine and manual transmission. Starting price - 191 030 UAH. It is unlikely that this car will suit a city dweller, but for those who spend most of their time outside the city, this is a good option. After all, already in the base the car has all-wheel drive.
Navara. Spacious and not the cheapest pickup truck with an increased level of comfort. Also only available with diesel engine 2.5. Transmission - mechanical or automatic. Base cost - 248 500 UAH.
Pathfinder. The next generation of this model will already lose the frame, but so far it is still there for the current version. Currently available at a price of 311 330 UAH. Already in the base - diesel and all-wheel drive. There are manual and automatic.
Mitsubishi
L200. This car comes with a 2.5 liter diesel engine, transmission - mechanics or 4-speed automatic. Vehicle drive - plug-in full or full. The basic version at the moment will cost 229,015 UAH. (special). Forced rear differential lock - by default.
Pajero Sport. Commonly known to share base with L200. Simply put, almost the same pickup truck, only with a covered trunk and an increased level of comfort. The starting price for today is UAH 259,985. Transmission - mechanical or automatic.
Toyota
Toyota is in no hurry to abandon the frame. As before, the Land Crusier Prado (150) and Land Cruiser (200) models have a frame base. The 200th "Corn" (as it is popularly called) has many versions. The cost in the official dealer network - from 760 873 UAH. up to UAH 855 326 There are two engines - a 4.6-liter gasoline engine with a capacity of 309 hp. and a 4.5-liter diesel engine with a capacity of 235 hp. Transmission - 6-speed, automatic.
land Cruiser Prado available in Ukraine at a price of 355,047 UAH. The range of engines includes three units. Two petrol - with a volume of 2.7 liters and 4.0 liters - and one diesel, with a volume of 3 liters and a power of 173 hp. Complete set options - as many as 7!
also in model range Toyota has a frame Hilux pickup, considered one of the most enduring cars in the world. Whether this is so, you can be sure, provided that there is at least 262,773 UAH for its purchase. That is how much the basic version costs with a 2.5-liter diesel unit with a capacity of 144 hp, which can only work with a mechanical one. A 3-liter diesel engine with a capacity of 172 hp is also available, it is aggregated with an automatic transmission.
And Toyota also has huge Tundra and Sequoia. They have a "Body on frame" design - as the Americans say, this is a frame on which the wheels are fixed, but the body is not rigidly tied to the frame. Despite the very impressive dimensions and voracious gasoline engines (4.0, 4.6 liters and 5.7 liters), in our country, judging by the number of these cars, there are enough fans of the largest Toyotas. - from 380 000 UAH. up to almost 800 000 UAH.
In addition to Tundra and Sequoia, our site presents prices for frame, and new. These cars are found on our roads, but what has become a discovery for us is the possibility of buying an "old" one, but new land Cruiser 70 series! It turns out that this model is still produced for certain markets, and in our country an almost ancient Toyota without a run can be bought through an unofficial dealer network. Price - 400-450 thousand hryvnia. For this money, a car with a diesel engine, a manual transmission and a whole arsenal of locks for the toughest off-road is offered. For the inveterate gourmet.
The model range of the South Korean brand includes one SUV with a frame at the base. This is the flagship Mohave costing from UAH 376,000. (according to the promotion for cars made in 2011) up to 414 100 UAH. By the way, the son of the honorary president of the UkrAvto corporation, Vakhtang Vasadze, drives such a car. For Ukrainians, quite a lot of trim levels and two engines are available - a 3.8-liter gasoline and a 3-liter turbodiesel. Four-wheel drive - by default. The gearbox is only automatic, but depending on the year of manufacture and type of engine, it can have from 5 to 8 (!) Steps.
Suzuki
Basically, frame SUVs are bulky and impressive cars. But Suzuki Jimny- exception to the rule. This kid has a solid frame construction and in many ways resembles his ancestor named Samurai. From a technological point of view, it is as simple as, for example, an UAZ. But it does have air conditioning. electronic systems security, etc. It cannot be said that this model is wildly popular, but it has its fans in Ukraine. At the moment, Jimny, which is called a small all-terrain vehicle, is available at a price of 178,200 UAH. (for vehicles manufactured in 2012). The engine is one - gasoline, with a volume of 1.3 liters and a power of 85 hp. There are two gearboxes - a 5-speed manual or a 4-speed automatic.
Daihatsu
Another "baby" with a frame is the Daihatsu Terios. Despite the fact that this model is sold by purely "gray" dealers, it can be considered very popular in Ukraine. This is evidenced by the number of such cars on our roads.
Daihatsu Terios - frame, with rigid rear axle and permanent all-wheel drive. Real SUV, only very small. In Ukraine, such a car without a run can be purchased for 176-225 thousand hryvnias.
Mercedes
Mercedes G-class is perhaps the most expensive car with frame. A car created for military needs, unfortunately, is often used for completely different purposes and in most cases does not see off-road. Fans of the "cube" (as they like to call this car in the CIS) appreciate it for its solid construction and high reliability. The fee is appropriate. A huge selection of configurations and engines allows you to choose a car for any requirements. In the official dealer network, the G-class costs at least 1 million hryvnias.
Land Rover
Defender is an infrequent guest on Ukrainian roads. It is not as comfortable as the Mercedes G-Class, both in terms of driving and interior design. But in terms of reliability, according to the owners, it has practically no equal. Yes, and on the patency to him can hardly be a claim. Today Defender is offered with a short and long base. The engine is a 2.4-liter turbodiesel. Permanent four-wheel drive, short overhangs and a reliable but stiff suspension - all these are attributes of a car for real men who only think about hunting and fishing. Price - from 336 353 UAH.
Jeep
Jeep also has a classic frame SUV - the legendary Wrangler. In Ukraine, this model is available with petrol and diesel units, as well as in 3- or 5-door versions. Transmission - mechanical or automatic.
"Three-door" costs from 380,000 hryvnia, five-door Wrangler - from 414,000 hryvnia.
Volkswagen
Dodge
A typical representative of American pickups. Big, voracious and, of course, has a frame base. There is a mass different options cabins, lengths, engines - for every taste. The only thing you should not count on is savings. Regardless of the type of engine, fuel costs will be as impressive as the size of the car. Cost - from 350,000 to 500,000 hryvnia.
Whether to pay attention
For an ordinary motorist who uses a car mainly in the city, the presence of a frame is not particularly important. After all, as already mentioned in the pros and cons of frame cars, they are controlled worse than models with a monocoque body. Nevertheless, if we talk about durability, frame SUVs remain the best in this parameter. That's just passive safety is not the "horse" of such cars. However, it all depends on the efforts of manufacturers and the amount of money invested in improving security. The choice is yours...
A frame car is the unequivocal choice of most motorists. What is attractive frame car? Types of frames, their advantages and disadvantages. Well, if anyone is not familiar with what a frame is on a car and why it is needed, read this article especially carefully. This is an important characteristic of the car and you need to know it!
What are the types of car frames.
Each car is a set of mechanical components and assemblies attached to the bearing part. For some vehicles, the supporting structure (base) is body, other's - frame or stretcher.
At the dawn of the automotive industry, the frame structure was used on all types of cars. Later, when it turned out that the installation of the frame was not justified due to the large weight and high cost of manufacturing on passenger cars, they began to use a load-bearing body as a base.
On trucks, vehicles with high traffic and today they install a frame structure.
The advantage of the frame is that it provides the best rigidity and strength of the structure for tearing, twisting, stretching compared to other types of load-bearing part. This factor directly affects the carrying capacity of the car, its off-road qualities.
The main types of car frames:
- Spinal;
- Spar frame
These types have their own varieties. For example, fork-spine refers to spinal frames, peripheral - to spar.
Spar frame
The most common frame design today.
Such a frame has two spars arranged longitudinally and several crossbars. Spars are made from a U-shaped profile (channel). The higher the load, the greater the height and thickness of the profile.
Crossbars have different design features. There are X- and K-shaped crossbars, as well as a straight shape. To install the mechanisms and assemblies of the car on the side members and crossbars, various fasteners and brackets are used. To fasten parts of the frame, rivet, bolted, welded and other connections are used.
Peripheral frame
It differs from the usual spar in that the spars were bent during manufacture so that there was the greatest distance between them. This is done so that the bottom of the car is as low as possible. Such frames were made and installed on american cars until the 60s of the XX century.
spinal frame
In the mid-20s of the last century, the Czechoslovak company Tatra developed a spinal frame.
The bearing part is made of a pipe, inside which all the elements of the transmission were located. With the help of this pipe, the engine was connected to the transmission. The power unit, gearbox and final drive, clutch are part of the frame elements. All these elements are rigidly fixed to the frame.
With the help of a cardan shaft located inside the pipe, the engine transmits torque to the transmission units. Only when all wheels are provided with independent suspension, it is possible to install the frame on the car.
Fork-spine frame
It was also invented in the Tatras. The engineers of this company abandoned the rigid attachment of the transmission and engine to the supporting central tube, as was done on the spinal frame. AT new design special forks appeared on both sides of the carrier pipe, on which the engine with the transmission is installed.
Main Benefits frame structure before others:
- high level of comfort (low noise and vibration),
- high load capacity, simple design
- ease of repair and Maintenance, cheap parts.
Flaws:
- volume decreases car interior,
- higher vehicle weight (increased fuel consumption)
- low passive safety (due to the impossibility of programming crumple zones)
- an increase in the overall price due to the cost of the frame.
Currently, passenger cars are made with a load-bearing body, and real (not SUV) SUVs are made on a frame.
When buying an SUV, you can roughly determine the class of the car by the presence or absence of a frame.
Greetings, my dear readers! In this publication, friends, we will understand the design features of car bodies, their varieties and find out what is better than a frame or a load-bearing body.
If you are the owner of a classic off-road vehicle built to overcome the toughest obstacles, then you will understand why it has a frame. Of course, this article will be of interest to those who want to deepen their knowledge about cars, who want to start from the basics - from their frame, skeleton.
To start in in general terms denote that there is a frame. In its simplest form, these are two parallel metal beams (spars), interconnected by a plurality of crossbars.
A suspension with wheels is attached to this structure, an engine is installed, and then a body is hung from above. And nothing prevents developers from hanging different bodies on the same frame - this is one of its advantages.
Frame as a basis vehicle appeared from the very beginning of automotive technology and has been actively used in this role for many decades. What is the reason for this longevity?
The point is the banal imperfection of technology, due to which other variants of the skeletons, for example, load-bearing bodies, were heavier and more difficult to manufacture. But time passed, new alloys appeared, conveyors improved and safety requirements increased.
All these factors pushed the frame frames in the passenger car segment into the background, giving way to load-bearing frames. In fairness, it must be said that the frames are not completely forgotten. On their basis, highly passable SUVs and trucks are still being created, because where there are high loads, such car frame structures have advantages.
Evolution and diversity of frames
And yet, what is better a frame or a load-bearing body ... If about frames, then frames are quite diverse in their execution. There are such types:
- spars;
- spinal;
- spatial.
The spar frame is a fairly simple and popular design. Two parallel spars with crossbars providing rigidity, which can be located both in the same plane and change their profile. This type of frame frame is used today in the production of trucks, as well as SUVs.
spinal frame
The spinal view is less popular, one might even say that it is now a rarity. The basis of such a core is one beam located in the middle, and crossbars are attached to it, like ribs. One of the features of the spinal frames is the suspension, which in this case can only be performed according to an independent scheme. The main carrier of such a frame were Tatra trucks.
Spatial or frame frames
What can unite buses and sports cars? As it turned out - spatial frames. These frames, more like load-bearing bodies, are like a 3D model of a car, but without body panels.
Frame and load-bearing bodies: confrontation
Well, friends, it remains for us to find out why, despite their simplicity, frame frames have given way under the sun to load-bearing bodies.
One of the main reasons was their low passive safety - when developing a car with a frame frame, it is almost impossible to create so-called deformation zones. In addition, the body itself, where the driver and passengers are located, is more vulnerable, and if we start to strengthen it with different elements, we will end up with a very heavy car, which is also unacceptable in modern realities.
On this, dear colleagues, let me take my leave. Subscribe to the newsletter and you will never miss the latest and interesting articles. Share with friends on social networks and discuss what you read, so you will learn the material more deeply.
car frame
The frame serves as a base on which all parts and mechanisms of the car and its body are fixed.
All trucks have a frame. The frame consists of two longitudinal beams - spars, connected by several cross members - traverses. The spars are made by stamping from sheet steel and have a trough or box-shaped section of a variable profile, most reinforced in the middle part. Parts of the frame are fastened with charcoal and kerchiefs on rivets or by welding.
Rice. 1. Frame truck
The front transverse beams serve to mount the engine. Brackets for attaching suspension parts are attached to the spars.
For trucks, in the rear of the frame, on special transverse beams, towing device, including a hook with a constipation and a shock-absorbing spring or with a rubber shock absorber. The hook is intended for connection of the trailers towed by the car.
Two simple hooks are attached to the front of the frame, used for towing the car in case of a malfunction, pulling it out of the mud, etc.
A metal buffer is attached to the front of the frame. The frame with all the parts assembled on it rests through the suspension parts on axles with wheels.
The frame is also equipped with large-capacity passenger cars with a significant distance between the axles of the wheels ("Seagull", ZIL -111).
Rice. 2. Bearing body passenger car
To obtain the necessary strength and eliminate the possibility of body deformations, the frame of cars is made of a special design, usually with an X-shaped transverse beam and beams with enlarged sections. Buffers are attached to the front and rear of the frame.
For passenger cars of small and medium capacity, a separate frame is usually absent and a rigid body base is used instead of a frame. Such a body is called a carrier. Cars "Zaporozhets", "Moskvich" and "Volga" have a load-bearing body structure.
In a car with a load-bearing body, the frame is replaced by a rigid body frame structure (Fig. 2), consisting of a floor reinforced with beams, a front part, side pillars, a roof and a rear part. These parts are equipped with amplifiers and connected by welding. In the front part, a short (sub-engine) frame is attached to the floor of the body with bolts or by welding, which serves to install power unit and front suspension of the car. Struts welded to the frame are bolted or welded to the body shield.
The frame of the car serves to mount the engine, chassis units, bodywork on it and, thus, is a load-bearing structure.
Rice. 3. Spar frame of the car ZIL -130: 1 - towing hook; 2 - buffer; 3 - shock absorber bracket; 4 - cross member; 5 - spar; 6 - towing device; 7 - spring brackets; c - engine mount bracket
All trucks, high class cars and some types of buses have a frame. By design, frames are spar, central (spinal) and X-shaped (combined).
The spar frame, which has received the greatest distribution, consists of two spars (longitudinal beams) interconnected by several crossbars (Fig. 3). A buffer with two towing hooks is attached to the front end of the frame, and a towing device is installed in the rear of the frame. Brackets for shock absorbers, springs, engine mounts, cabs and platforms are attached to the spars.
Spars and crossbars are stamped from sheet steel and connected to each other with rivets. The cross section of the spars has a trough-shaped profile with the greatest height and rigidity in the middle, more loaded part of the frame. The crossbars may have a special shape required for the installation of certain components and assemblies of the vehicle.
The frameless design of the car provides for the use of a load-bearing body and is used in small and medium class cars and some types of buses. This allows to reduce the weight of a passenger car by about 5%, a bus - by 15%. The car body is a rigid welded structure, including a floor reinforced with spars and crossbars, a front end with two side members of the sub-frame, a rear part with a panel, sidewalls with uprights, fenders and a roof.
The frame of the car during movement experiences significant vertical dynamic loads from the forces of inertia of the sprung parts - the frame itself, the engine, the clutch and gearbox, and the body. The frame is calculated for bending and torsion strength and is made of low carbon or low alloy steels with good strength and ductility.
The frame of the car is a skeleton on which all the mechanisms of the car are fixed. The frame must have high strength and rigidity, but at the same time be light and shaped in such a way that a lower center of gravity of the car is possible to increase its stability.
There are three main types of frames:
- spars, consisting of two longitudinal beams (spars), connected by crossbars;
- central, having one longitudinal beam or pipe as a ridge;
- combined, combining both principles in their design (the middle part of the frame is performed as a central one, and the ends are made spar).
On trucks, spar frames are most widely used, consisting of two longitudinal parallel beams - spars connected by cross members (traverses), using welding or rivets. In areas subjected to the greatest loads, spars have more high profile, and sometimes enhanced by local inserts. The material for the spars are steel trough-shaped profiles (channels). The spars are sometimes made curved in the vertical and horizontal planes.
Rice. 3. Automobile frames: a and b - spar; c - central; g - combined
Brackets are riveted or screwed to the spars for attaching springs, steps and a spare wheel, as well as buffers and a towing device. The buffers protect the body from damage during collisions, and the towing device is used to tow trailers.
The frame is the basis for mounting units, mechanisms and car body.
The truck frame consists of two longitudinal beams - spars, and several cross members. The frame elements are made by stamping and connected with each other by rivets. The spars along the length have an unequal cross section; in the middle part, and three-axle vehicles and in the back, they are of great height. The crossbars are made in such a shape that provides fastening to the frame of the corresponding mechanisms.
In front of the frame, a buffer and towing hooks are attached to the spars. ZIL cars on the front buffer have a reclining footboard. A towing device and removable elastic buffers are installed on the rear cross member. On ZIL vehicles, there are two eyebolts on the rear cross member for attaching emergency trailer chains.
The towing device consists of a hook with a latch, a rubber buffer with thrust washers, a body with a bracket and a cap. The hook latch is held in the closed or open positions by a pawl. To eliminate spontaneous disengagement, a cotter pin attached to a hook on a chain is inserted into the holes of the latch and pawl. Lubrication of rubbing surfaces is carried out through a grease fitting. The towing device of the Ural-375D car uses a spring as an elastic element, and the device itself is fixed in a special cross member, which is attached from below to the rear ends of the frame side members.
Rice. 4. Frame car ZIL -131:
1 - front buffer; 2 - towing hook; 3 - starting handle bracket; 4, 9, 12, 13, 14 - crossbars; 5 - mudguard; 6 - bracket for the rear engine mount; 7 - upper shock absorber bracket; .8-- bracket for fastening the electromagnetic valve for controlling the inclusion of the front axle; 10 - bracket rear suspension cabins; 11 - bracket for fastening the transfer case; 15 - trailer chain eye; 16 - towing device; 17 - brackets for rear spring buffers; 18, 20 - front spring brackets; 19 - spar
The main faults of the frame are the weakening of the rivets, the appearance of cracks and kinks in the frame. Loose rivets are detected by the rattling sound they make when tapped with a hammer. Cracks and breaks are determined by external inspection. Loose rivets should be replaced with new ones or bolts with spring washers should be used instead.
Due to its high strength and rigidity, the frame does not require special maintenance. It is necessary to clean it daily from dirt and dust (snow), to wash it. At TO-1, the condition of the rivet joints and the integrity of individual frame elements are checked. It is necessary to monitor the condition of the frame coloring and timely tint the places where the coloring is broken.
The frame of the car must be of high strength and rigidity. The frame should be light and shaped to allow a lower center of gravity for the vehicle, which increases its stability.
Rice. 5. Frames:
a - with parallel spars; b - with tapering spars; in - with curved spars; 1 - spar; 2 - cross member
Spar frames got their name from the longitudinal beams-spars that form their basis, connected to each other by crossbars by welding or riveting. In places subjected to the greatest loads, the spars have a higher profile, and are sometimes reinforced with local inserts. The spars are often made curved in the vertical and horizontal planes. To protect against damage to the radiator and fenders, buffers in the form of transverse beams are installed at the front end of the frame, which perceive shocks when the car hits an obstacle.
The front cross member of the frame has a shape specially adapted for mounting the engine. To strengthen the crossbars, scarves and squares are sometimes superimposed at the points of their attachment to the spars.
In cars with load-bearing bodies, there is no frame, but there is a subframe for attaching the engine and front wheels to the body.
On fig. 6 shows a frame of a truck, consisting of two side members having a channel profile of variable section, and cross members. Spars and cross members are made of mild steel sheet.
The front buffer and towing hooks are attached to the spars at the front with brackets and bolts.
For fastening the radiator and the front engine mounts, a front cross member riveted to the spars is used. The rear supports for the engine are brackets.
The front springs are attached to the brackets. Rubber buffers prevent the springs from hitting the side member. The rear springs are attached to the brackets. In a loaded car, the ends of the springs (additional springs) rest on the support platforms.
On the left side member there is a socket for batteries and bracket for mounting the crankcase of the steering mechanism. On the right side member there is a bracket 6 for fastening the spare wheel.
The intermediate support of the cardan shaft is reinforced from the bottom of the second cross member, to the upper part of which is attached rear support cabins.
The towing device is attached with a spacer and braces to the rear cross member. A turn signal bracket is placed at the rear end of the right side member, and a rear light bracket is placed at the rear end of the left side member.
Rice. 6. Frame car ZIL -130:
1 - front buffer; 2 - towing hook mounting bracket; 3 - towing hook; 4 - engine mounting bracket; 5 - spar amplifier; 6 - spare wheel mounting bracket; 7 - bracket for direction indicator; 8 - stretching; 9 - towing device; 10, 13, 16, 17 and 24 - crossbars; 11 - rear light bracket; 12 - spacer for fastening the towing device; 14 - rear spring mounting bracket; 15 - support pads of the sprung; 18 - platform mounting bracket; 19 - spar; 20 - battery socket; 21 - bracket for fastening the crankcase of the steering mechanism; 22 - front spring mounting bracket; 23 - rubber buffer; 25 - bracket for guiding the crank
The brackets serve to secure the platform, and the bracket to guide the crank.
To increase the rigidity and strength of the frame, amplifiers are attached to its spars.
When towing a car, hooks are used.
The frame is the base of the truck and serves to install all units on it. To ensure the correct interaction of the units, the frame must have high rigidity. The frame consists of two longitudinal beams-spars having a channel section, and several transverse beams-traverses. Frame beams are made of flat steel by hot stamping. For the spars, low-alloy steel is used, and for the traverse, carbon steel is used. Along the length, the spars have a variable section - larger in the middle part and smaller at both ends. Brackets of springs, side engine mounts, power steering, etc. are riveted to them.
Category: - Vehicle Chassis