Body-on-frame is a car construction method in which a separate object is mounted on a relatively stiff frame or chassis carrying the engine and drivetrain. It was the original method for building cars and continues to this day. At the end of the 19th century frames may be made of wood reinforced by steel plates but in the early 20th century the steel frame or chassis quickly became the standard.
The mass production of all metal bodies began with Budd Company and Dodge Brothers but before that the body, like that of their replaced carriages, was made of metal panels that were fastened to wood (mostly ash) (body) -frame.
Mass production of all metal bodies became common in the 1920s but Europe, with the exception, followed almost a decade later. European custom-made or "coachbuilt" cars typically contain multiple wood framing or use aluminum alloy castings.
The unibody design in which the panels inside the body support cars on suspensions developed by European manufacturers in the late 1920s with Budd USA (which owns a number of large factories in Europe) and its technical knowhow but not in the United States until the 1950s and generally later. Due to the high cost of designing and developing these structures and the high cost of specialized machines to make the enormous pressure required by this style of construction is not used by low volume manufacturers who might build the equivalent of welded steel tubes to form the appropriate space frames.
Currently some new vehicles still have separate chassis, most common pickup trucks and SUVs.
Video Body-on-frame
History
Ford Model T brings the body-on-frame over tradition of horse-drawn carriages, helping to facilitate high volume manufacturing on a moving assembly line. In the US, frequent changes in automotive design make it necessary to use a ladder framework rather than a unibody construction to allow design change without having to replace the chassis, allowing frequent changes and improvements to the car bodywork and interior (where they are most visible to customers) while leaving the chassis and the driveline does not change, and thus keep the cost down and the design time short. It's also easy to use the same chassis and driveline for some very different cars. Especially in the days before computer-aided design, this is a huge advantage.
Most of the small passenger vehicles switched to unibody construction in the late 1930s. This trend began with cars such as the Citroen Traction Avant (1934) and Opel Olympia (design of General Motors) introduced in 1935. Trucks, bus manufacturers and large-volume or made cars in the US continue to use separate bodies on "conventional" frames. Body-on-frame remains the preferred construction method for heavy-duty commercial vehicles (especially those intended to carry or pull heavy loads, such as trucks and some SUV vehicles) but due to increased production volume more and more SUVs and crossover SUVs switch to unibody frames. Mass-marketmakers Ford, General Motors and Chrysler leave true body-on-frame SUVs, choosing, when sales volume allows, for more efficient unibody construction. Toyota currently produces the most body-on-frame SUV with 4Runner, FJ Cruiser, Land Cruiser, Sequoia, Lexus GX and LX followed by Nissan with Armada, Patrol, Xterra and Infiniti QX56/80. The Panther Ford platform, which was discontinued in 2011 , is the last series of traditional passenger cars built in this way.
One of the variants used by Chevrolet because its Corvette combines the inner frame into the frame.
Medium to full monocoque construction is the 'semi-monocoque' used by Volkswagen Beetle and Renault 4. It uses a lightweight separate chassis made of sheet steel panels that form the 'chassis platform', to benefit from the traditional chassis, but with more weight lower and greater stiffness. Both chassis is used for several different models. The mid-1930s designed Volkswagen utilize bodyshell for structural strength as well as chassis - hence 'semi-monocoque'. Traditionally the chassis has "compliance", they are designed to allow multiple plays. When suspensions are upgraded, they can not function properly unless they support rigid structures such as those intended to be provided by unibody or monocoque constructions.
Lincoln Town Car once dominated the American limousine market because it was the last American luxury car made on a body-on-frame system and it was easily extended for livery work. With Town Car suspended since 2011, the de facto replacement is the Lincoln Navigator SUV.
Maps Body-on-frame
Advantages and disadvantages
Benefits
- It's easier to design, build, and modify. (in part due to computer-aided design now (CAD) for built-in vehicles)
- Less noise when traveling, because the squealing and wobbling groans are usually related to body movement because the pressure and tension does not sound so much, and the road noise from the tires is much 'away', all because the bodywork is isolated from the chassis with rubber pads in around the hook bolts, or by suspending the body on the chassis.
- Easier to fix after an accident. This is very important for first responders (police, fire, EMS) and anyone who needs their vehicle for a living. Ruin the wings of bolts, bumpers etc: can be replaced easily, and in the case of 'working vehicles' they can return to earnings status immediately. A monocoque (one piece) vehicle shell will require special repairs, which could mean long delays before the vehicle can be used again.
- Can allow more torsional stretch before generating (truck, truck-base SUV, off road)
- Vehicles mounted high on separate chassis such as trucks and off-road SUVs that are not likely to experience rust damage caused by moisture, mud, rock, sand, water, snow, and other more serious damage such as transmission or damage Engine oil oil is often caused by rocks.
Losses
- Complete vehicles are often heavier than monocoque shells, resulting in reduced performance and higher fuel consumption.
- Body-on-frame vehicles with high ground clearance like trucks and off-road SUVs have a high center of gravity, sacrificing performance on their roads.
- Torsional stretch during cornering can endanger the handling and grip of the road.
- Many body-on-frame vehicles do not have an inbuilt crumple zone, so there is a higher chance of injury in a bad crash.
Example
Here is a list of production cars, SUVs, and light pickup trucks available in the United States that currently have body-on-frame construction.
See also
- Vehicle frame
- Coach Work
- Spaceframe
- Subframes
- Superleggera
- Chassis backbone
- Mobil eksoskeleton
References
External links
- Ford assembly featuring body-on-frame car (historic)
Source of the article : Wikipedia
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