Types of automobile frames. Frame SUVs: review of the most famous models. What about off-road?

Car frame

The frame serves as the base on which all parts and mechanisms of the car and its body are mounted.

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 variable profile, most reinforced in the middle part. The frame parts are fastened together using charcoals and gussets with rivets or by welding.

Rice. 1. Truck frame

The front cross members are used to mount the engine. Brackets are attached to the side members for attaching suspension parts.

For trucks, a towing device is installed in the rear of the frame on special transverse beams, which includes a hook with a lock and a shock-absorbing spring or a rubber shock absorber. The hook is designed for attaching trailers towed by a vehicle.

Two simple hooks are attached to the front of the frame, used for towing the car when it breaks down, pulling it out of the mud, etc.

A metal stop - a buffer - is attached to the front of the frame. The frame with all the parts assembled on it rests through the suspension parts on an axle with wheels.

The frame is also equipped with large-capacity passenger cars that have a significant distance between the wheel axles (Chaika, ZIL-111).

Rice. 2. Load-bearing body of a passenger car

To obtain the necessary strength and eliminate the possibility of body deformation, the frame of passenger cars is made of a special design, usually with an X-shaped cross beam and with beams having increased sections. Buffers are attached to the front and rear parts of the frame.

Small and medium-sized passenger cars usually do not have a separate frame and use a rigid body base instead of a frame. Such a body is called a load-bearing body. The Zaporozhets, Moskvich and Volga cars have a load-bearing body structure.

In a passenger car with monocoque 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 reinforcements and are connected by welding. In the front part, a short (sub-engine) frame is bolted or welded to the body floor, which serves to install the power unit and the front suspension of the car. The struts, welded to the frame, are bolted or welded to the body panel.

The frame of the car serves to mount the engine, chassis units, and body on it and, thus, is a load-bearing structure.

Rice. 3. Spar frame of the ZIL-130 car: 1 - towing hook; 2 - buffer; 3 - shock absorber bracket; 4 - cross member; 5 - spar; 6 - towing device; 7 - spring brackets; c - engine support bracket

All trucks, high-class cars and some types of buses have a frame. The design differs between spar, central (spine) and X-shaped (combined) frames.

Spar frame, which received greatest distribution, consists of two spars (longitudinal beams) connected to each other by several cross members (Fig. 3). A buffer with two towing hooks is attached to the front end of the frame; a towing device is installed at the rear of the frame. Brackets for shock absorbers, springs, engine mounts, cab and platform are attached to the side members.

The spars and cross members are stamped from sheet steel and connected to each other with rivets. The cross section of the side members has a trough-shaped profile with the greatest height and rigidity in the middle, more loaded part of the frame. Cross members may have a special shape necessary for the installation of certain components and assemblies of the vehicle.

The frameless design of the car involves the use of a monocoque body and is used in passenger cars small, middle class and some types of buses. This makes it possible to reduce the weight of a passenger car by about 5%, a bus by 15%. The body of a passenger car is a rigid welded structure, which includes a floor reinforced with side members and cross members, a front end with two side members of the sub-engine frame, a rear part with a panel, sidewalls with racks, fenders and a roof.

When moving, the car frame experiences significant vertical dynamic loads from the inertial forces of the sprung parts - the frame itself, the engine, the clutch and gearbox, and the body. The frame is designed for strength in bending and torsion 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 mounted. The frame must have high strength and rigidity, but at the same time be lightweight and have a shape that allows for a lower center of gravity of the vehicle to increase its stability.

There are three main types of frames:
— spar, consisting of two longitudinal beams (spars) connected by cross members;
- central, having one longitudinal beam or pipe as a backbone;
- combined, combining both principles in their design (the middle part of the frame is made as the central part, and the ends are made spar).

On trucks The most widely used are spar frames, consisting of two longitudinal parallel beams - spars, connected by cross members (traverses), using welding or rivets. In areas subject to the greatest loads, the spars have a higher profile and are sometimes reinforced with local inserts. The material for the side members is steel trough-shaped profiles (channels). Spars are sometimes made curved in vertical and horizontal planes.

Rice. 3. Automobile frames: a and b - spar; c - central; g - combined

Brackets are riveted or screwed to the side members for attaching springs, running boards and a spare wheel, as well as buffers and a towbar. Buffers protect the body from damage during collisions, and the towbar is used to tow trailers.

The frame is the basis for fastening units, mechanisms and the car body.

The frame of a truck consists of two longitudinal beams - side members, and several cross members. Frame elements are made by stamping and connected to each other with rivets. The spars have an unequal cross-section along their length; in the middle part, and in the case of three-axle vehicles in the rear, they have a greater height. The crossbars are made in a shape that ensures that the corresponding mechanisms are attached to the frame.

At the front of the frame, a buffer and towing hooks are attached to the side members. ZIL cars have a folding step on the front buffer. A towing device and removable elastic buffers are installed on the rear cross member. On ZIL vehicles, the rear cross member has two eye bolts for attaching trailer emergency chains.

The towing device consists of a hook with a latch, a rubber buffer with thrust washers, a housing with a bracket and a cap. The hook latch is held in the closed or open position by a pawl. To eliminate spontaneous disengagement, a cotter pin is inserted into the holes of the latch and pawl, attached to a hook on a chain. Lubrication of rubbing surfaces is carried out through a grease nipple. The towing device of the Ural-375D vehicle 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. ZIL-131 car frame:
1 - front buffer; 2 - towing hook; 3 - bracket starting handle; 4, 9, 12, 13, 14 - crossbars; 5 - mudguard; 6 - rear engine mount bracket; 7 - upper shock absorber bracket; .8-- mounting bracket solenoid valve front axle activation control; 10 - cabin rear suspension bracket; 11 - transfer case mounting bracket; 15 - trailer chain eye; 16 - towing device; 17 - rear spring buffer brackets; 18, 20 - front spring brackets; 19 - spar

The main malfunctions of the frame are weakening of the rivets, the appearance of cracks and kinks in the frame. Loose rivets are identified by the rattling sound they make when tapped with a hammer. Cracks and breaks are determined external inspection. Loose rivets should be replaced with new ones or bolts with spring washers should be installed instead.

Due to its high strength and rigidity, the frame is specially maintenance does not require. It is necessary to clean it daily from dirt and dust (snow), and wash it. During 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's paint and promptly touch up the areas where the paint is damaged.

The car frame must be highly durable and rigid. The frame must be lightweight and shaped to allow the vehicle's center of gravity to be lower, which increases its stability.

Rice. 5. Frames:
a - with parallel spars; b - with tapering spars; c - with curved spars; 1 - spar; 2 - cross member

Spar frames get their name from the longitudinal beams-spars that form their basis, connected to each other by cross members by welding or riveting. In areas subject to the greatest loads, the spars have a higher profile, and are sometimes reinforced with local inserts. Spars are often made curved in vertical and horizontal planes. To protect the radiator and fenders from damage, buffers are installed at the front end of the frame in the form of transverse beams that absorb impacts when the car hits an obstacle.

The front cross member of the frame is shaped specifically for engine installation. To strengthen the crossbars, gussets and squares are sometimes applied at the places where they are attached to the side members.

In cars with monocoque bodies there is no frame, but there is a subframe for attaching the engine and front wheels to the body.

In Fig. Figure 6 shows a truck frame consisting of two side members having a channel profile of variable cross-section and cross members. Spars and cross members are made of low-carbon steel sheets.

The front buffer and tow hooks are attached to the side members at the front using brackets and bolts.

To secure the radiator and front engine mounts, there is a front cross member riveted to the side members. The rear supports for the engine are brackets.

The front springs are attached to brackets. Rubber buffers prevent the springs from hitting the side members. The rear springs are attached to brackets. For a loaded vehicle, the ends of the springs (additional springs) rest on the support platforms.

On the left side member there is a socket for batteries and the steering gear housing mounting bracket. On the right side member there is a bracket 6 for fastening the spare wheel.

The intermediate support of the propeller shaft is strengthened at the bottom of the second cross member, to the upper part of which the rear support of the cabin is attached.

The towbar is secured with a spacer and guy wires to the rear cross member. At the rear end of the right side member there is a turn signal bracket, and at the rear end of the left side member there is a bracket rear light.

Rice. 6. ZIL-130 car frame:
1 - front buffer; 2 - towing hook mounting bracket; 3 - towing hook; 4 - engine mounting bracket; 5 - spar amplifier; 6 - spare wheel mounting bracket; 7 - turn signal bracket; 8 - stretching; 9 - towing device; 10, 13, 16, 17 and 24 - cross members; 11 - rear light bracket; 12 - spacer for fastening the towbar; 14 - rear spring mounting bracket; 15 - support platforms of the spring; 18 - platform mounting bracket; 19 - spar; 20 - battery socket; 21 - bracket for fastening the steering gear housing; 22 - front spring mounting bracket; 23 - rubber buffer; 25 - bracket for directing the starting handle

The brackets are used to secure the platform, and the bracket is used to guide the starting handle.

To increase the rigidity and strength of the frame, reinforcements are attached to its side members.

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 proper 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. The frame beams are made from strip steel by hot stamping. Low-alloy steel is used for the spars, and carbon steel is used for the traverse. Along the length, the spars have a variable cross-section - larger in the middle part and smaller at both ends. Brackets for springs, side engine mounts, power steering, etc. are riveted to them.

category: - Car chassis

Long-term studies have shown that while the car is moving, the body is affected by uncontrollable forces, 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 body elements as bending, compression, twisting The task repair work is to restore the designed endurance of the body components in accordance with the manufacturer’s settings. The technology of repair work must be such that the endurance of the repaired parts corresponds to the unrepaired parts of the car.

For cars with a monocoque body, the functions of the frame are either performed by the body itself, or the frame (or subframes replacing it) is structurally integrated with the body and cannot be separated from it without violating the structural integrity. Typically the body is attached to the frame using bolted brackets with thick rubber pads to reduce vibration.

All units are attached to the car frame: 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.

Nowadays, frame chassis are used primarily on tractors and trucks, but in the past, many passenger cars also had a frame chassis. “Rigid” SUVs often have a separate frame.

Distinguish the following types frames: spar, peripheral, spinal, fork-spine, load-bearing base, lattice (aka tubular).

Spar frame with X-shaped cross member

Spar frames consist of two longitudinal spars and several cross members called “traverses,” as well as fasteners and brackets for installing the body and components.

The shape and design of the side members and cross members may be different; There are tubular, K-shaped and X-shaped cross members. Spars, as a rule, have a channel cross-section, and the length of the section usually varies: in the most loaded areas, the height of the section is often increased. They can be located both parallel and at some angle relative to each other.

Peripheral frames

Sometimes considered as a type of spar. In such a frame, the distance between the side members in the central part is increased so much that when the body is installed, they are located directly behind the door sills. Since the frame is weakened in the places of transition from the usual distance between the side members to the increased one, special box-shaped reinforcements are added in such places, called torque boxes in English-speaking countries.

This solution allows you to significantly lower the floor of the body, placing it completely between the side members, 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 side members directly behind the body sills greatly improves the vehicle's safety in the event of a side impact.

Spine frames

Main structural element such a frame is a central transmission pipe that rigidly connects the engine crankcases and power transmission units - clutch, gearbox, transfer case, main gear (or main gears on multi-axle vehicles), inside which there is a thin shaft that replaces the cardan shaft in this design. Required independent suspension all wheels.

The advantage of this scheme is high torsional rigidity; In addition, it allows you to easily create modifications of cars with different numbers of drive axles. However, repairing units enclosed in a frame is extremely difficult. Therefore, this type of frame is used very rarely, and has completely fallen out of use on passenger cars.

Fork-spine frames

A type of backbone frame, in which the front and sometimes the rear parts are forks formed by two side members and used to mount the engine and components.

Unlike the backbone frame, the power transmission housings are usually (but not always) made separate, using a conventional driveshaft if necessary. Representative Tatra cars from T77 to T613, among others, had such a frame.

This type often includes X-shaped frames, which are considered by some sources to be a type of spar frames. Their spars in the central part are very close to each other and form a closed tubular profile. This frame was used on Soviet cars"Chaika" 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 this design. Currently, this scheme is considered quite promising due to the possibility of building the most different cars like on a platform.

Lattice

Also called tubular frame or spaceframe.

Lattice frames take the form of a space truss with a very high torsional stiffness-to-weight ratio (that is, they are lightweight and very torsionally strong).

Such frames are used either on sports and racing cars, for which low weight with high strength is important, or on buses, for whose angular bodies it is very convenient and technologically advanced to manufacture.

When it comes to repair technology, the question often arises of how to repair or change an element that is, in its own way, design features bearing. For example, consider a frontal angled deformation of the front of a car, in which the front panel, hood, fender, mudguard and side member are deformed. Of these, in this unit we can distinguish two removable elements - the wing and the hood - and three or more welded ones - the radiator frame, the mudguard, the spar. During repair work on deformed elements, it is necessary to ensure the functions provided by the manufacturer (symmetry of the structure, symmetry of the shape of the body and its elements, safety of passengers while driving, etc.).

Therefore, if we accept repairs to the mudguard and fender, then the hood, radiator frame and spar must be replaced. When replacing the hood, it is possible to control the repaired surface of the wing at the point where it adjoins the hood, control the location of the radiator frame when replacing it, and control the connection of the repaired mudguard to it. When replacing the radiator frame, it is possible to control the geometry of the hood opening and the correct fit 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 is necessary to take into account that, conditionally, repairs will be applied to the wing and mudguard without heating and welding. If heat is applied to one of the elements being repaired to shrink the metal or weld a gap or technological cut, then the other element must be replaced with a new one. IN in this case It makes the most economic sense to replace the wing. If 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 during editing, be it a separate amplifier, a mudguard amplifier or another element.

It must also be remembered that although the manufacturer designed the structural endurance of body elements to have a safety factor of n = 1.3–1.5, and for the edges of the body, which are susceptible to the combined action of turbulent forces generated by the gearbox and wheels during movement, the safety factor equal to 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 repaired parts of the car in line with unrepaired ones, the ideal option for repairing this unit would be to replace all elements that cannot be fixed without the use of heating or welding technological cuts.

An example of spar repair on a frame car

The right side member under the floor of the passenger seat is affected by through corrosion to such an extent that the brackets of the front axle arms are not only unable to perform their functions, but are also torn off.

For repairs, a used spar with a mudguard was purchased, from which the necessary parts were cut out.

In order to securely place the support under the threshold, it had to be replaced, as well as partially replacing the floor.

After this, the front axle arms are removed, the damaged part of the spar is cut out and replaced. The work is not easy, because the cutouts for distributing the load are made complex, sometimes access to them for welding is difficult, and seams must be applied on both sides.

The photo shows a floor reinforcement on which a cover plate is welded to the spar.

We weld the repair parts to the floor and protect the seams with sealant on all sides.

We apply an anti-gravel coating to all repaired areas and carry out internal anti-corrosion treatment threshold and spar and get the result of the repair.

If the result of a car collision is significant deformation, you must first 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 vehicle is moving, residual stresses can cause stress in the mountings of shock absorbers and bushings, and sometimes cause them to rupture.

But in some cases, preliminary straightening of the body with installed mechanical units can facilitate access to the units to be removed, for example, to the engine 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 a stand.

If an impact on the front or rear half-axle causes deformation of the base of the body, you can also straighten the body by fixing (hooking) the tension mechanism on mechanical units, such as wheel rims or suspension arms, that have become deformed. Editing is done in the direction directly opposite to the impact. Performing such an operation is possible only in the case when the impact fell directly on the front or rear half-bridge, and its replacement is necessary.

It is also necessary to replace the ball joints and steering rods. Straightening using a jack or other hydraulic mechanism is used to restore the shape or straighten a deformed part. However, when starting work, do not forget that if you sharply edit a body part, deformation of the adjacent 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 the folds. And after stretching with a jack, it is necessary to remove all internal stresses by tapping (using a straightening hammer) the entire area that has been straightened.

To ensure that there will be no subsequent reverse movements of the straightened sections of the body due to residual stresses, the surface is tapped through a wooden pad in the direction of impact. If the straightened body does not change its shape, then the straightening operation was performed correctly. Otherwise, adjustments must be made again until the geometry is within the tolerances established by the vehicle manufacturer.

If a car receives 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 a 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 side surface restoration is straightening the B-pillar, which is wrapped with a pulling chain. To protect the rack from damage and distribute the force evenly, a wooden strip is laid between the rack and the chain.

Longitudinal stretching, performed simultaneously with lateral stretching, can be performed in various ways. If the deformation is concentrated in the lower part of the body, the base is directly straightened by securing the clamps to the sill flanging. The jack is placed between the two clamps and, under pressure, moves them longitudinally as simultaneous lateral stretching is carried out. If the deformation is concentrated in the upper part of the body, stretching is performed in the longitudinal direction from the front and rear parts of the body.

Work on straightening and checking new side members must be carried out using precision equipment, which is available only in workshops.

In any case, geometry diagnostics are best done using good equipment, the selection of which will be discussed in the next issue.

In preparing this article, materials from open sources were used in accordance with the GNU Free Documentation License.

Now frame SUVs, which a couple of decades ago were the real kings of off-road, are gradually giving way to modern models of jeeps and crossovers with a monocoque body or an integrated frame.

Comfort and efficiency are put at the forefront, and cross-country ability and reliability are relegated to second place. Nevertheless, such cars have their own segment - they are popular in Northern and South America, in Russia, the countries of the Near and Middle East, as well as Africa. In a word, where “road surface” is a rather relative concept, and to get from point “A” to “B”, you need to use a “framework” or an armored personnel carrier.

Let's look at the most famous SUVs on a frame that were produced before and now.

One of the most famous cars in the list of frame SUVs, produced in a pickup truck, first saw the light back in 1968. Initially, Hilux was not focused on cross-country ability - the engine was too weak, small wheelbase and a single-wheel drive did not allow the pickup to tackle serious off-road conditions. The same applies to Honda Pilot, which we wrote about in a previous article.

But everything changed with the advent of the third Hilux generation Regular Cab in 1978. It was installed for the first time four-wheel drive, powerful and responsive engines - 1.8 and 2.4 liter petrol, and 2.2 liter diesel.

The SUV was actively sold and was appreciated in third world countries.

Suffice it to say that the Libyan-Chadian war of 1986–87 was called the “Toyota War” due to the fact that Chadian troops actively used Toyota Hilux pickups.

The powerful frame made it possible to install a heavy machine gun and a rocket launcher in the body, and the unpretentious engine and indestructible suspension provided Chadian army units with amazing mobility in the desert.

According to military experts, the use of these frame SUVs allowed Chad to repel an attack by the Libyan army, which was much better armed. Afterwards, in many African and Middle Eastern countries, field commanders widely used the car as patrol vehicles, light fire support and for transporting goods.

Starting from the fifth generation, Hilux becomes more comfortable and less utilitarian. There are a lot of options, several cab options and the like - but the frame structure remains unchanged.

The modern eighth generation of Toyota Hilux was launched into production in May 2015. The new reinforced frame with increased rigidity provides the chassis with the necessary solidity, allowing it to overcome any off-road conditions.

As power units, the Hilux is equipped with two variants of powerful and responsive diesel engines with a volume of 2.4 and 2.8 liters, 150 and 177 liters. With. respectively, 6-speed manual transmission and the same automatic transmission. The first has a torque of 400 Nm, the second – 450 Nm. All this, coupled with a ground clearance of 227 mm in the low part of the chassis, makes the pickup a king on any off-road.

Toyota Land Cruiser

Land Cruiser is rightfully considered one of the most popular frame SUVs in the world. Although it currently confidently occupies the premium segment, one of the representatives of which is the 2016 Toyota Prado, for quite a long time it was a “workhorse”, designed specifically for use in difficult conditions and calmly competed with the leading American SUVs on the market.

Success for the Land Cruiser, which fully justified the nickname “Land Cruiser,” came with the advent of the 60 series.

Here, for the first time, the combination of a simple independent leaf spring suspension, a powerful diesel engine and a ladder-type frame was tested, which brought success to the model and was subsequently used on other modifications.

The apotheosis was the 100th series, produced since 1998.

Despite the fact that it belongs to the premium SUV segment, off-road performance is impeccable. Impact-absorbing elements began to be installed in the frame, and in the 105-series, a modernized version of the “hundred”, dependent front suspension is still used to this day. A new line has also been developed for the LC 100 power plants, which includes gasoline and diesel engines, working perfectly at low and medium speeds.

Nissan Patrol

Appearing in 1958 as a continuation of a licensed copy of the American Willys Jeep, Patrol 4W65 and subsequent versions were offered exclusively for the needs of the army. But since the end of 1960, these frame SUVs entered the civilian market, where they were appreciated by residents of rural areas - the powerful frame made it possible to transport up to a ton of cargo in the back, and the reliable and unpretentious suspension made the car almost indestructible on any terrain.

The Patrol 160 model, produced since 1960, was seriously modernized, and the designers managed to combine reliability, cross-country ability, comfort and a relatively low price in the car.

The SUV has become so successful that in Middle Eastern countries, for example, in Iran, it is still considered one of the most popular.

A reinforced frame with spring suspension and solid axles, simple and unpretentious diesel engines and a two-stage transfer case allowed the car to overcome any obstacles. Don’t forget about the frankly simple and reliable design chassis, which rarely failed.

Until 2010 in the family Nissan Patrol two more versions of inexpensive frame SUVs appeared: Y60 and Y61.

They were modernized in terms of improved comfort - the suspension became softer, because springs and levers began to be installed instead of springs, a spacious interior best quality etc. More powerful power units also appeared: diesel engines from 2.8 to 4.2 liters (112-200 hp) and gasoline V-shaped 4.5 and 4.8 liters. Particularly popular were the 4.2-liter naturally aspirated diesel engines TD42, most of which were equipped with a simple in-line injection pump - the engines easily “maintained” 200-400 thousand km without overhaul in very harsh conditions.

But the flagship version of the Patrol Y62 is a rather controversial model. Immediately after its appearance, it became clear that it enjoys commercial success exclusively in the oil monarchies of the Persian Gulf (like Gelik Brabus), where they prefer only two types of cars - elite sports cars or huge premium-segment SUVs.

While maintaining its cross-country ability (frame, ground clearance, transfer case and a powerful 5.6-liter engine with a torque of 560 Nm and 400 hp), the SUV acquired too many options aimed at comfort. As a result, the price is about 4 million rubles not in the top configuration - naturally, buying such a car for off-road driving is at least stupid.

When starting a conversation about frame SUVs, we must not forget about the American market, where such off-road conquerors are in well-deserved demand. There are several reasons - from the need for actually light and passable trucks for various needs and to the presence of serious off-road conditions in the same Colorado, Montana, Nevada and Alaska.

That's why monsters like the Dodge Ram 1500 are very popular in the USA - a real pickup truck that can easily carry half a ton of cargo.

A powerful frame with mixed (torsion bars + springs) or spring suspension, all-wheel drive and a displacement engine has become the calling card of the model. The first generation was launched in 1981, and Dodge introduced the fourth in 2012.

The new Ram 1500 features improved body aerodynamics, a reinforced frame and a wide range of engines, the weakest of which is a 3.7-liter gasoline V-six with a capacity of 218 hp. With. But those for whom this is not enough can order a version with gasoline engines 4.7, 5.7, 8.0 and 8.3 liters, as well as two powerful turbodiesels of 5.9 and 6.7 liters.

Concluding the review of the best frame SUVs, we need to mention one of the most titled representatives of this type - the famous LR Defender, the undisputed winner of almost all known trophy raids.

It is noteworthy that for many years during production - and the first Defender was released in 1948, the car's spartan appearance and poor interior did not affect its popularity at all.

In general, as fans of the model joke, Defender’s appearance is as conservative as Britain, which remains a constitutional monarchy.

Essentially, this SUV is a searing mixture of strengths and weaknesses. Ladder frame coupled with long-travel suspension, good body geometry, torquey low-speed diesel engine, all-wheel drive with a two-speed transfer case and a locking center differential - provide phenomenal cross-country ability on steeply rough terrain.

In 1997, several enthusiasts managed to drive this car to Elbrus - a documented fact.

But on the other hand, comfort in Defender is an extremely relative concept even in the latest models, unlike compact crossover Range Rover Evoque. The developers left it spartan and simple - the side mirrors are adjusted manually, not to mention the frankly uncomfortable back row seats and other disadvantages. But the Defender is a living legend, sitting in which you can look down on any, even the most expensive SUV.

Video

For dessert, watch a video where real jeeps overcome severe off-road conditions. Crossovers never even dreamed of.

Each car is a collection of mechanisms and systems mounted on a supporting part. Cars are produced in which the role of the load-bearing part is performed, but there are cars in which all mechanisms and systems are installed on the frame.

car frame

The frame structure was initially used on all types of cars, but over time in production passenger cars they began to use a load-bearing one, and frames still continue to be used, but only on trucks.

They also did not abandon frame structures in the production of off-road vehicles, so most SUVs also have a frame supporting part. The advantage of using a frame is to provide a more rigid vehicle structure, which in turn makes it possible to transport larger loads.

Types of car frames

The use of frame structures on cars began almost at the dawn of the automobile era. During this time, several basic types of car frames were proposed:

spar frame;
and spinal.

Each of these types of frames have variations. A type of spar frame is the so-called peripheral one. And in addition to spinal frames, cars with fork-spine frames were also produced.

Spar frame

The most common frame structure is the spar frame.

The structure of a vehicle's spar frame Toyota Land Cruiser 200:
1 — front suspension mounting bracket; 2 - cross member; 3 — spar; 4 — body mounting bracket.

This frame consists of two spars, which are located longitudinally, as well as with cross members. Spars are made from channels with different section heights. In places that will be more loaded, the height is greater.

Cross members can also have different designs; there are ordinary, straight shapes, as well as K- and X-shaped ones. To ensure the installation of vehicle mechanisms, brackets and fastenings for them are installed on the side members and cross members. To fasten frame elements together, rivets, bolts or welding can be used.

A distinctive feature of the peripheral frame from a conventional spar frame is that during the manufacture of the spars they were bent, which led to the fact that in the middle there was the greatest distance between the spars. This was done in order to be able to position the bottom of the car as low as possible. Such frames were used in America in the production of passenger cars.

Spinal frame

Backbone-type frames for cars were developed by Tatra specialists. And such frames were used mainly on cars of this company. The main load-bearing part of the spinal frame is a pipe that connects the engine and all elements.

Frame Tatras

Essentially power unit, as well as , gearbox and final drive are also frame elements. The fastening of all these mechanisms is rigid. The torque from the engine to the transmission elements is carried out by a shaft that is installed inside the pipe. The use of such a frame structure is only possible if all the wheels of the vehicle are provided with independent suspension.

The backbone frame is good because it provides high torsional rigidity, easy and quick creation of cars with a different number of drive axles, but since some of the car’s mechanisms are located inside the frame structure, it is quite difficult to carry out repair work.

Fork-spine type frames were also developed by Tatra employees. In this case, they abandoned the rigid mounting of the engine and transmission to the supporting central pipe. Instead, they installed special forks on both sides of the supporting pipe, onto which the engine is installed.

Before we move on to describing the pros and cons of such an automotive design as a frame, let's figure out what a frame car is, and also get acquainted with the history of its origin and evolution.

A frame or, as the Americans say, “body-on-frame” is a way of constructing a car when a rigid frame carries the chassis (engine, transmission, transfer case etc.), and the body is separately attached to the top of this entire structure.

This assembly method was used on the very first car models and continues to be used to this day (though not as often as the monocoque method). The very first frames were made of wood (usually ash), but in the 30s they were finally replaced by more reliable steel spar frames.

Spar truck frame with spring rear suspension and fixed axle, as well as sound-absorbing plates and insulation.

Today, in the passenger segment, frames are rapidly giving way to monocoque (monocoque body) structures, where the body itself is the main (or only) load-bearing element.

It is noteworthy that at one time the conditions for the development of the automotive industry in the USA required the use of a frame, as this made it possible to quickly respond to customer demand and change appearance body and interior without making any changes to the chassis. The updated body was simply attached to a frame with a set of units that were used in the previous model.

This significantly reduced the development time of a “new” car and its final cost, respectively. This was a huge advantage, especially given the lack of computer-aided design (CAD) systems.

Since the thirties, there has been a trend to use a monocoque body, for example in the Opel Olympia or Citroen Traction Avant. Already in the 60s, most small passenger cars use a monocoque, while the frame is used only for trucks and some types of buses.

This trend has continued to this day - the use of the frame has become the prerogative of manufacturers of powerful commercial vehicles, pickup trucks and rare “real” SUVs.

You probably know what this led to - modern manufacturers place maximum emphasis on production (with rare exceptions).

Few people know, but there was also an intermediate version of the semi-monocoque, which was used in cars such as the Volkswagen Beetle and Citroen 2CV. This design featured a separate lightweight pressed steel chassis that retained some of the benefits of a real frame but was much lighter and stiffer.

Another frame with installed units

So, it’s time to talk about why we actually gathered here: what is good about the frame and what are its weak points.

Advantages and disadvantages of frame SUVs

Pros:

Body-on-frame vehicles are easier to design, manufacture, and modify (an advantage offset by the ubiquity of CAD);
Better noise insulation and vibration suppression, since the cabin with passengers is isolated from the frame using rubber gaskets in the area of the mounting bolts. However, today sound insulation modern cars with a monocoque body it is practically no worse;
Easier to repair after accidents;
Frame cars have a longer service life and are more durable;
Frame SUVs are traditionally predisposed to install powerful power units;
This design is better suited for towing and off-road use, thanks to even load distribution, reduced roll and overall strength and reliability.
High seating position and good visibility;
They simplify the visual assessment of the dimensions of the car from the passenger compartment;

Flaws:

Significantly heavier body cars, as a result, lower productivity and increased consumption fuel;
As a rule, frame cars are inferior to body cars in handling;
Problems with passive safety. There is no so-called “crumple zone” in the design, resulting in a higher chance of death or serious injury in a collision.

This article uses photographs from the portfolio of illustrator Kevin Hulsey (khiart.com)