Chassis, Frame and Car Body

Chassis, Frame and Car Body

 

•  Definition of Chassis- It is defined as the internal framework which consists of a frame supporting the vehicle and all the major units responsible for propelling and controlling of the vehicle.

• Classification of Chassis-

1. Conventional control chassis- In this type, engine is mounted in front of the driver’s cabin. Hence this type avoids full utilization of the space. 

Fig. Conventional Chassis

      2. Semi forward control chassis- Here half part of the engine is in the front (outside driver’s cabin) and remaining half is in the driver’s cabin. Example: TATA SE series vehicles

Fig. Semi Forward Chassis

     3. Full forward control chassis- Engine is mounted completely inside the driver’s cabin and hence maximum utilization of space is achieved.  TATA E series vehicles

Fig. Full Forward Chassis

• Conventional Construction-

 This type of a chassis construction assumes frame as a basic unit and various components are mounted on it along with the bolted body.

Ø Function of the frame-

i)          To support the chassis components and the body

ii)        To withstand static and dynamic loads without causing deflection or distortion.

Ø Loads on the frame-

i)      Weight of the passengers and vehicle- It causes vertical bending of the side members.

ii)   Vertical loads when vehicle comes across a bump or hollow- Due to this longitudinal torsional stress is developed

iii)      Loads due to side wind, cornering force (while taking a turn), road camber, etc. – Side members experience lateral bending

iv)   Load due to wheel impact- If wheel collides with some road obstacles then particular wheel remains obstructed while other tends to move forward.

v)       Braking torque and engine torque- Side members bend in vertical plane.

vi)    Sudden impact loads during collision- This may cause a general collapse.

 

 Ø Types of Chassis Frame-

i) Conventional Frame- It is further divided into three sub types listed as follows-

a.     Channel Section: Good resistance to bending

b.     Tabular Section: Good resistance to torsion

c.     Box Section: Good resistance to both bending and torsion

ii) Integral Frame- This type of frame is used now days in most of the cars. Frame is absent and all the assembly units are directly attached to the body. As the long frame is eliminated completely, it is cheaper. The only disadvantage of this frame is repairing is difficult.

 

Fig. Integral Frame

               iii)  Semi – Integral Frame- The half frame is fixed in the front end on which    engine, gear box and front suspension is mounted. It has an advantage when vehicle is met with an accident the front frame can be taken easily to replace the damaged chassis frame. This type of frame is used in FIAT cars and some of the European and American cars.

Fig. Semi - Integral Frame

 

 Requirements of Car Body- 

        i)   The body should be light in weight.

   ii)       It should have minimum no. of components.

   iii)     It should provide sufficient space for passengers and luggage.

   iv)     It should withstand vibrations while in motion.

   v)       It should offer minimum resistance to air.

  vi)       It should be cheap and easy in manufacturing.

  vii)     It should be attractive in shape and color.

  viii)   It should have uniformly distributed load.

  ix)       It should have long fatigue life.

  x)         It should provide good vision and ventilation.

 

      Car Body Nomenclature-

Fig. Car Body Nomenclature

Types of Car Bodies-

 i) Closed Cars- 

 a. Saloon   b. Hatchback    c. Coupe   d.  Limousine

ii) Open Cars-
a. Sports   b. Convertible

iii) Special style- 
a. Estate cars    b. Station wagon 

iv) Transport vehicles- 
a. Van   b. Truck   c. Articulated vehicle   d. Bus  e. Coach 


v) Other-
a. Tractor with articulated trailer 
b. Half body truck 
c.Dump truck 
d.Tanker
e. Delivery truck


 

Fig. Types of car bodies