Subframe

Last updated
The Lamborghini Aventador has a carbon fibre central monocoque, with front and rear steel subframes, mounting the mechanics. Lamborghini Aventador LP 700-4 chassis - Flickr - J.Smith831.jpg
The Lamborghini Aventador has a carbon fibre central monocoque, with front and rear steel subframes, mounting the mechanics.
Front subframe of a Vauxhall Vectra on display in Bedford Museum VectraFrontSubframeBMuseum.JPG
Front subframe of a Vauxhall Vectra on display in Bedford Museum

A subframe is a structural component of a vehicle, such as an automobile or an aircraft, that uses a discrete, separate structure within a larger body-on-frame or unibody to carry specific components like the powertrain, drivetrain, and suspension. The subframe is typically bolted or welded to the vehicle. When bolted, it often includes rubber bushings or springs to dampen vibrations. [1] [2] [3]

The primary purposes of using a subframe are to distribute high chassis loads over a wide area of relatively thin sheet metal of a monocoque body shell and to isolate vibrations and harshness from the rest of the body. For example, in an automobile with its powertrain contained in a subframe, forces generated by the engine and transmission can be sufficiently damped to prevent disturbing the passengers. Modern vehicles use separate front and rear subframes to reduce overall weight and cost while maintaining structural integrity. Additionally, subframes benefit production by allowing subassemblies to be created and later introduced to the main body shell on an automated line.

There are generally three basic forms of the subframe:

  1. A simple "axle" type, which usually supports the lower control arms and steering rack.
  2. A perimeter frame, which supports the lower control arms, steering rack, and engine.
  3. A perimeter frame with full support, which supports the lower control arms, steering rack, engine, transmission, and possibly the full suspension, commonly used in front-wheel-drive cars.

Subframes are typically made of pressed steel panels that are thicker than body shell panels and are welded or spot-welded together. Hydroformed tubes may also be used in some designs.

The revolutionary monocoque, transverse-engined, front-wheel-drive 1959 Austin Mini set the template for modern front-wheel-drive cars by using front and rear subframes to provide accurate road wheel control while maintaining a stiff, lightweight body. The 1961 Jaguar E-Type (XKE) used a tubular space frame–type front subframe to mount the engine, gearbox, and long bonnet/hood to a monocoque "tub" passenger compartment. Beginning with the 1960s, subframes saw regular production with General Motors' X- and F-platform bodies, and the Astro/Safari mid-size vans.

Subframes are prone to misalignment, which can cause vibration and alignment issues in the suspension and steering components. Misalignment is caused by space between the mounting bolts and the mounting hole. Several companies in the automotive aftermarket, including TyrolSport in the US and Spoon Sports in Japan, offer solutions for subframe misalignment and movement issues.

1963 Jaguar E-Type rear subframe front view.jpg
Rear subframe and suspension of a 1963 Jaguar E-Type
Bodengruppe Ford Focus 2011.jpg
Underbody with front and rear subframes of a 2011 Ford Focus

Related Research Articles

<span class="mw-page-title-main">Axle</span> Central shaft for a rotating wheel or gear

An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle is supported. In the latter case, a bearing or bushing sits inside a central hole in the wheel to allow the wheel or gear to rotate around the axle. Sometimes, especially on bicycles, the latter type of axle is referred to as a spindle.

<span class="mw-page-title-main">Unsprung mass</span> Portion of a vehicle not supported by its suspension system

The unsprung mass of a vehicle is the mass of the suspension, wheels or tracks, and other components directly connected to them. This contrasts with the sprung mass supported by the suspension, which includes the body and other components within or attached to it. Components of the unsprung mass include the wheel axles, wheel bearings, wheel hubs, tires, and a portion of the weight of driveshafts, springs, shock absorbers, and suspension links. Brakes that are mounted inboard are part of a vehicle's sprung mass.

<span class="mw-page-title-main">Maserati Bora</span> Motor vehicle

The Maserati Bora is a two-seat, rear mid-engine, rear-wheel drive sports car and grand tourer, manufactured by Maserati from 1971 to 1978. In common with other Maserati cars of the era, it is named after a wind, Bora being the wind of Trieste. The Bora was the company's first mid-engined street car and ended Maserati's reputation for producing fast but technologically out of date cars, also being the first Maserati with four wheel independent suspension. In contrast, competitor Lamborghini had first used full independent suspension in 1964. The Bora was the second-most expensive car of the 1970s following Lamborghini Countach.

<span class="mw-page-title-main">Chapman strut</span> Type of automotive suspension design

The Chapman strut is a design of independent rear suspension used for light cars, particularly sports and racing cars. It takes its name from, and is best known for its use by, Colin Chapman of Lotus.

<span class="mw-page-title-main">Body-on-frame</span> Automobile construction method using a separate body on a structural frame

Body-on-frame is a traditional motor vehicle construction method whereby a separate body or coach is mounted on a strong and relatively rigid vehicle frame or chassis that carries the powertrain and to which the wheels and their suspension, brakes, and steering are mounted. Whereas this was the original method of building automobiles, body-on-frame construction is now used mainly for pickup trucks, large SUVs, and heavy trucks.

<span class="mw-page-title-main">Messerschmitt Kabinenroller</span> Motor vehicle platform

The Messerschmitt Kabinenroller was a series of microcars made by RSM Messerschmitt from 1953 to 1956 and by Fahrzeug- und Maschinenbau GmbH, Regensburg (FMR) from 1956 to 1964. All the Messerschmitt and FMR production cars used the Kabinenroller's monocoque structure, featuring tandem seating and usually a bubble canopy.

<span class="mw-page-title-main">Beam axle</span> Automobile mechanism

A beam axle, rigid axle, or solid axle is a dependent suspension design in which a set of wheels is connected laterally by a single beam or shaft. Beam axles were once commonly used at the rear wheels of a vehicle, but historically, they have also been used as front axles in four-wheel-drive vehicles. In most automobiles, beam axles have been replaced with front (IFS) and rear independent suspensions (IRS).

<span class="mw-page-title-main">General Motors K platform (RWD)</span> Motor vehicle platform

The General Motors K platform was the automobile platform designation used for the rear wheel drive Cadillac Seville midsize luxury models from 1975 to 1979.

The following outline is provided as an overview of and topical guide to automobiles:

<span class="mw-page-title-main">Motorcycle frame</span> Frame of a motorcycle

A motorcycle frame is a motorcycle's core structure. It supports the engine, provides a location for the steering and rear suspension, and supports the rider and any passenger or luggage. Also attached to the frame are the fuel tank and battery. At the front of the frame is found the steering head tube that holds the pivoting front fork, while at the rear there is a pivot point for the swingarm suspension motion. Some motorcycles include the engine as a load-bearing stressed member; while some other bikes do not use a single frame, but instead have a front and a rear subframe attached to the engine.

<span class="mw-page-title-main">Vehicle frame</span> Main supporting structure of a motor vehicle

A vehicle frame, also historically known as its chassis, is the main supporting structure of a motor vehicle to which all other components are attached, comparable to the skeleton of an organism.

Motorcycle components and systems for a motorcycle are engineered, manufactured, and assembled in order to produce motorcycle models with the desired performance, aesthetics, and cost. The key components of modern motorcycles are presented below.

<span class="mw-page-title-main">GTM Libra</span> Motor vehicle

The Libra was launched by GTM Cars Ltd on the UK kitcar market in 1998. Three years in development it was a collaboration between GTM Cars directors Peter Beck & Paddy Fitch, designer Richard Oakes and suspension designer Bryn Davies.

<span class="mw-page-title-main">Jaguar independent rear suspension</span> Common component of a number of Jaguar production cars since 1961

Jaguar's independent rear suspension (IRS) unit has been a common component of a number of Jaguar production cars since 1961, passing through two major changes of configuration up to 2006 and last used in the Jaguar XK8 and Aston Martin DB7. This article concentrates on the first generation Jaguar IRS, which firmly established the marque's reputation for suspension sophistication, combining as it did smooth ride with excellent roadholding and low levels of noise, vibration, and harshness (NVH). The two generations overlap in time due to their being used in both full size and sports models that were updated at different times.

The Audi R8 LMS Cup was a one-make sports car racing series by Audi based in Asia. Audi R8 LMS Cup cars were based on the Audi R8 LMS (GT3).

<span class="mw-page-title-main">Platform chassis</span>

A platform chassis is a form of vehicle frame / automobile chassis, constructed as a flat plate or platform, sometimes integrating a backbone or frame-structure with a vehicle's floor-pan.

Pull-rod suspension and push-rod suspension refer to a specialised type of automotive suspension system which is largely based on a double-wishbone system, incorporating elements of the commonly used MacPherson strut.

This glossary of automotive terms is a list of definitions of terms and concepts related to automobiles, including their parts, operation, and manufacture, as well as automotive engineering, auto repair, and the automotive industry in general. For more specific terminology regarding the design and classification of various automobile styles, see Glossary of automotive design; for terms related to transportation by road, see Glossary of road transport terms; for competitive auto racing, see Glossary of motorsport terms.

References

  1. "Subframes & Engine Cradles". Aluminum Extruders Council. Retrieved 25 June 2022.
  2. "What You Need to Know About Subframe Repair". CarParts.com. 2023-08-03. Retrieved 2024-07-10.
  3. Kilchermann, Lori (2024-05-23). "What is a Subframe?". WikiMotors.com. Retrieved 2024-07-10.