CAR CHASSIS DESIGN

Car Chassis Design

Car Chassis Design

In the case of vehicles, the term chassis means the frame plus the "running gear" like engine, transmission, driveshaft, differential, and suspension. A body (sometimes referred to as "coachwork"), which is usually not necessary for integrity of the structure, is built on the chassis to complete the vehicle. For commercial vehicles chassis consists of an assembly of all the essential parts of a truck (without the body) to be ready for operation on the road.[1] The design of a pleasure car chassis will be different than one for commercial vehicles because of the heavier loads and constant work use.[2] Commercial vehicle manufacturers sell “chassis only”, “cowl and chassis”, as well as "chassis cab" versions that can be outfitted with specialized bodies. These include motor homes, fire engines, ambulances, box trucks, etc.

In particular applications, such as school busses, a government agency like National Highway Traffic Safety Administration (NHTSA) in the U.S. defines the design standards of chassis and body conversions.[3]

An armoured fighting vehicle's chassis comprises the bottom part of the AFV that includes the tracks, engine, driver's seat, and crew compartment. This describes the lower hull, although common usage of might include the upper hull to mean the AFV without the turret. A chassis serves as basis for platforms on tanks, armored personnel carriers, combat engineering vehicles, etc.

Backbone: The tunnel becomes a primary load bearing member. This is a potentially fine design, and if we were building a new car from scratch, we would seriously consider a backbone. But , this is not a new car, it's a replica of a classic! Because it is designed around the original Ford engines (and we wanted our customers to have several different transmission choices), the bulk of a compatible structural tunnel was unacceptable, especially considering the passenger compartment was a fairly narrow one to begin with. A backbone would make it impossible to maintain the look of the original interior and engine compartment. It would also create servicing difficulties.

A variation to the sheet metal backbone is one that uses small tubes to create the central structure.  TVR's Griffith was built like that - with an enormous tunnel.  The Shelby Daytona Coupe added a tubular backbone to the original 289 chassis. It probably added 50% to the overall stiffness of the car!  See below.

 Then there is the issue of engine compartment esthetics.  With our rectangular tube chassis, we can duplicate the round-tube X (with the 427SC) or the spring tower (with the 289FIA) at the front of the engine to maintain visual accuracy.

A true space frame has small tubes that are only in tension or compression - and has no bending or twisting loads in those tubes. That means that each load-bearing point must be supported in three dimensions. It is nearly impossible to build an efficient space frame around the Cobra body. The rockers are simply too shallow, and the tunnel shaped incorrectly to make a reasonably triangulated ...