FIELD OF THE INVENTION
The present invention relates to a lightweight car with framed body (2) and welded unique joints (J1-J21) in a space frame configuration powered by an electric motor (1) integrated with a front wheel drive transmission system with batteries.
BACKGROUND OF THE INVENTION AND PRIOR ART
The car manufacturing industry is coming up with new designs to make light weight and cost effective cars. If the car is light weight, the speed and related performance will increase. Now a days steel is used for constructing the vehicle and this due to the fact that steel is much cheap in comparison with other metals. Aluminum is a much light weight metal, but slightly expensive in comparison with steel.
There exists no design with fully aluminum extrusion body (2). Since the cost of aluminum was on the higher side no one has done any trial with this.
OBJECTS OF THE INVENTION
The main object of the present invention is to provide a lightweight car of metal extrusion-based body (2) with welded unique joints (J1-J21) in a space frame configuration, having an electric motor (1) integrated with a front wheel drive transmission system.
Yet another object of the present invention is to provide a fully aluminum extrusion based vehicle.
Yet another object of the present invention is to provide a fully aluminum extrusion based vehicle.
Still another object of the present invention is to provide a light weight and cost effective vehicle.
Still another object of the present invention is to provide a specific design for using the aluminum with unique welded body joints (J1-J21).
Still another object of the present invention is to provide a unique shock absorber. Still another object of the present invention is to provide a cross-car beam (3) between B- pillars (4) above floor level to enhance side impact protection.
Still another object of the present invention is to provide a notched joint (7) of rear rail (6a) to rear seat cross-member (6b) to enhance rear impact protection. Still another object of the present invention is to develop a lightweight car having metal extrusion-based chassis.
Still another object of the present invention is to provide an electrical as well as mechanical car using the present invention.
STATEMENT OF THE INVENTION
The present invention relates to a lightweight car of metal extrusion-based body (2) with welded unique joints (J1-J21) in a space frame configuration, having an electric motor (1) integrated with a front wheel drive transmission system, said car comprises; cross-car beam (3) between B-pillars (4) above floor level for enhanced side impact protection, front shock tower (5) consisting of two extruded members laid out in the form of a compound L section, and notched joint (7) of rear rail (6a) to rear seat cross-member (6b) for enhanced rear impact protection, and also,
a method of manufacturing a lightweight car of metal extrusion-based body (2) with welded unique joints (J1-J21) in a space frame configuration, having an electric motor (1) integrated with a front wheel drive transmission system, said method comprises steps of, attaching cross-car beam (3) between B-pillars (4) above floor level for enhanced side impact protection, mounting front shock tower (5) consisting of two extruded members laid out in the form of a compound L section with McPherson struts having coiled springs, and joining notched joint (7) of rear rail (6a) to rear seat cross-member (6b) for enhanced rear impact protection to obtain the lightweight car.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
Figure 1 shows lightweight front wheel drive electric vehicle with typical body joints (Jl- J21).
Figure 2 shows the prototype of the vehicle.
Figure 3 illustrates the structure of the unique front shock tower (5).
Figure 4 Shows the completed vehicle built on the frame.
Figure 5 shows the front view of motor gear box (la) and drive shaft (lb) assembly.
Figure 6 illustrates the side impact protection strategy using a cross beam. Figure 7 shows the joining strategy of left rear rail (6a) with rear seat cross-member (6b). Figure 8 shows comparison of front door velocities with and without cross beam. Figure 9 shows comparison of B-pillar velocities with and without cross-car beam (3). Figure 10 shows comparison of rear door velocities with and with out cross-car beam (3). Figure 11 shows attaching rear rail (6a) to seat cross-member (6b) with an ordinary welded lap joint.
Figure 12 shows undesirable twisting of rear rail (6a) to seat cross-member (6b) joint in rear impact simulation.
Figure 13 shows rear impact simulation with notched joint (7) that resists twisting in rear impact simulation.
DETAILED DESCRIPTION OF THE INVENTION
The main embodiment of the present invention is a lightweight car of metal extrusion- based body (2) with welded unique joints (J1-J21) in a space frame configuration, having an electric motor (1) integrated with a front wheel drive transmission system, said car comprises;
• cross-car beam (3) between B-pillars (4) above floor level for enhanced side impact protection,
• front shock tower (5) consisting of two extruded members laid out in the form of a compound L section, and
• notched joint (7) (8) of rear rail (6a) to rear seat cross-member (6b) for enhanced rear impact protection.
In yet another embodiment of the present invention wherein the car is either electric vehicle or non-electric vehicle.
In still another embodiment of the present invention is the body (2) of the car is made preferably by aluminium extrusion members.
In still another embodiment of the present invention wherein the car frame is optionally covered with plastic or thin gage metallic exterior body panels.
In still another embodiment of the present invention is the car provides about 21 welded unique joints (jl to j21) for optimal combination of rigidity and crashworthiness.
In still another embodiment of the present invention is the front shock tower (5) is provided for mounting McPherson struts with coiled springs.
In still another embodiment of the present invention is the electric motor (1) integrated with the front wheel drive transmission system permits driving at a fixed or variable gear ratios.
In still another embodiment of the present invention is the McPherson strut is mounted in
an inclined manner without interference with the shock tower pillars (5 a).
In still another embodiment of the present invention is the L-section provides adequate
area for supporting top plate (5b) for mounting the McPherson strut.
In still another embodiment of the present invention wherein the front wheel drive system
is leveraged by coupling the DC motor with variable speed gear box (la) with provision
for clutch.
In still another embodiment of the present invention is the range of the vehicle can be easily extended with the help of hybrid configuration which is a combination of motor and an IC engine.
In still another embodiment of the present invention is a method of manufacturing a lightweight car of metal extrusion-based body (2) with welded unique joints (J1-J21) in a space frame configuration, having an electric motor (1) integrated with a front wheel drive transmission system, said method comprises steps of,
• attaching cross-car beam (3) between B-pillars above floor level for enhanced side impact protection,
• mounting front shock tower (5) consisting of two extruded members laid out in the form of a compound L section with McPherson struts having coiled springs, and
• joining notched joint (7) of rear rail (6a) to rear seat cross member (6b) for enhanced rear impact protection to obtain the lightweight car.
In still another embodiment of the present invention wherein the body (2) of the car are made preferably by aluminium extrusion members.
In still another embodiment of the present invention is the method provides about 21 welded unique joints (jl to j21) for optimal combination of rigidity and crash worthiness.
In still another embodiment of the present invention is the McPherson strut is mounted in an inclined manner without interference with the shock tower pillars (5a). In still another embodiment of the present invention wherein the front wheel drive system is leveraged by coupling the DC motor with variable speed gear box (la) with provision for clutch.
In still another embodiment of the present invention the lightweight car is having metal extrusion-based chassis,
The design is for a small four-wheeler (please refer to CAD model in Fig. 1 and actual prototype in Fig. 2) that will comfortably accommodate five adults (including driver). The chassis and upper body (2) are presently made completely from extruded aluminium members with welded joints (J1-J21) in a space frame configuration resulting in a lightweight vehicle. However, the body (2) could also be made with steel members and would be lightweight compared to conventional cars because of the body architecture chosen here. The stiffness and strength of the car are derived from its space frame body (2) shown in Fig. 2. There is adequate ground clearance for the vehicle to be operated on rough and bumpy roads. The roof height ensures easy ingress-egress for passengers. The car has a rigid body (2) to guard against vibrations that can be induced by engine or motor and road undulations. The crumple zones in the front and rear will protect occupants against collisions. The vibration resistance and crashworthiness of the lightweight vehicle platform have been verified through advanced computer-aided design and simulation. The vehicle frame can be covered with plastic (or thin gage metallic) exterior body panels after addition of door beams for necessary door strength and side impact safety. The unloaded weight of the vehicle in its completed form (see Fig. 4) is about 600 kg.
The car is currently equipped with an electric motor (1) that is integrated with a front wheel drive system (see Figs. 2 and 5). The vehicle is quiet with zero emission to the environment. The range of the vehicle can be easily extended with the help of a hybrid configuration (i.e. a combination of motor and an IC engine).
Description of originality and novelty:
The unique features and novelties of the present lightweight electric vehicle are described
below:
• It has a fully aluminium extrusion-based chassis and body (2) (see Figs. 1 and 2); no other vehicle is sold anywhere in the world which has a space frame design with only extruded aluminium members.
• The framed construction consists of welded body joints (J1-J21) providing an optimal combination of rigidity and crashworthiness (Fig. 1).
• The front of the car has a unique design of shock towers (5) (Figs. 2 and 6) for mounting McPherson struts with coiled springs. The rear rails (6a) are designed for protecting occupants against frontal collisions.
• The vehicle has an integrated electric motor (1) with a front wheel drive transmission system (Figs. 2 and 5) which will permit driving at a fixed or variable gear ratios. The assembly is unique for an electric car and can be found in no other electric car (such as Reva) in India. The front wheel drive system adopted in the present vehicle provides superior traction on slippery roads compared to rear wheel drive vehicles with a front engine.
• The vehicle is designed to ensure safety under side and rear impact conditions. A member (Fig. 6) welded between left and right B-pillars (4) just above floor level is a new concept for robust protection against side impact that may be caused by much heavier vehicles. The rear rails (6a) have unique joints (Fig. 7) with rear lateral cross- members (6b) that will help in retaining body integrity during rear collisions.
In the present application, patent protection is being sought for the following items:
(1) Vehicle body design architecture with disposition of members and typical joints marked as J1 through J21 in Fig. 1.
(2) Detailed shock tower (5) constructions with McPherson strut mounting strategy (Fig.
3)
(3) Assembly of motor and front transaxles (i.e. integrated gearbox and differential with half-shafts) delivering power to front wheels (Fig. 5)
(4) Cross-car beam (3) between B-pillars (4) just above floor for enhanced side impact protection in a lightweight car such as the present one (Fig. 6). This is a new strategy when compared with commercially sold small cars.
(5) Joining strategy of rear rails (6a) with rear seat cross member (6b) (Fig. 7). Further explanations of Items 1-5:
Item 1:
The welded joints (J1-J21) and members between them play a key role in the overall integrity of the space frame vehicle body. The vehicle has to support both bending and torsional loads caused by payload, tractive forces and torques and aerodynamic and road loads. Additionally, the space frame should protect occupants during crashes by optimally deforming and absorbing impact energy. The disposition of members and joints (J1-J21) as shown in Fig. 1 makes the current design well-equipped to meet the stated requirements. This novelty of design holds irrespective of the material for body (2) construction, i.e. steel, aluminium, fibre-reinforced composites, etc.
Item 2:
The shock tower (5) (Fig. 3) consists of two extruded members laid out in the form of a compound L-section when cut with a horizontal plane and viewed from top. This disposition allows the McPherson strut to be mounted in an inclined manner without interference with the shock tower pillars (5a) (see front view in Fig. 5). Simultaneously, the L-section provides adequate area for supporting the top plate (5b) for mounting the McPherson strut, and enables the shock tower (5) to carry tensile and compressive shock loads during vertical jounce and rebound movements respectively of the front suspension system. The shock towers (5) as designed thus provide extra rigidity and stability to the vehicle when its front wheels go over bumps, pot-holes, etc.
Item 3:
A front wheel drive assembly (see Fig. 5) offers benefits of superior traction in powered wheels on wet and slippery roads. The McPherson strut system adopted also offers additional package space for advanced braking systems such as ABS (Anti-lock Braking System). The only commercially sold electric car in India namely Reva has a rear wheel drive system with a constant gear ratio. In the present case, the benefits of a front wheel drive system are leveraged by coupling the DC motor with a variable speed gear box (la) with provision for clutch. The latter system enables the vehicle to perform more efficiently at low and high speeds.
Item 4:
The cross-car beam (3) in Fig. 6 is a strategic member that provides superior protection to both front and rear occupants during side impact, i.e. if the current car is hit on its side by another vehicle approaching towards it roughly at right angles. The cross-member under consideration significantly improves occupant safety by lowering the initial peak velocities of front door, B-pillar and rear door on the struck side of the vehicle. Advanced nonlinear computer-aided dynamic analyses simulating NHTSA (National Highway
< »
Traffic Safety Administration)-administered LINCAP (Lateral Impact New Car Assessment Program) test in USA clearly show the benefit of the present cross-member. Figs. 8 to 10 give the comparisons of structural velocities (which are indications of severity of occupant injury) for two cases: when the cross-car beam (3) in Fig. 6 is removed and when the same is present. It can be seen from these figures that the initial peaks of front door, B-pillar and rear door velocities on the struck side of the vehicle due to a Moving Deformable Barrier at 38.5 mph (62 kph) are significantly reduced when the lateral member is present thereby reducing the injury potential of the occupants sitting close to the impacted side of the vehicle.
Item 5:
The novelty of the notched joint (7) of rear rail (6a) to rear seat cross-member (6b) can be appreciated by comparing the behaviour of an ordinary joint with the current joint during a rear impact i.e. when the present vehicle is hit at the rear by another vehicle. In an ordinary joint (see Fig. 11), the rear rail (6a) would be placed on top of the rear seat cross-member (6b) and welded to it. During a rear impact, the joint will twist as shown in Fig. 12 which is based on a mathematical model analysis.
With the joint disposition shown in Fig. 7 and being claimed as a novelty, significantly improved performance results in rear impact simulation as depicted in Fig. 13 with no noticeable joint twisting.
Advantages of the invention:
The advantages of the present lightweight vehicle are described below:
• It has a fully aluminium extrusion-based chassis and body (2) (see Figs. 1 and 2); no other vehicle is sold anywhere in the world which has a space frame design with only extruded aluminium members.
The framed construction consists of welded body joints (J1-J21) providing an optimal combination of rigidity and crashworthiness (Fig. 1).
The front of the car has a unique design of shock towers (5) (Figs. 2 and 6) for mounting McPherson struts with coiled springs. The rear rails (6a) are designed for protecting occupants against frontal collisions.
The vehicle has an integrated electric motor (1) with a front wheel drive transmission system (Figs. 2 and 5) which will permit driving at a fixed or variable gear ratios. The assembly is unique for an electric car and can be found in no other electric car (such as Reva) in India. The front wheel drive system adopted in the present vehicle provides superior traction on slippery roads compared to rear wheel drive vehicles with a front engine.
The vehicle is designed to ensure safety under side and rear impact conditions. A member (Fig. 6) welded between left and right B-pillars (4) just above floor level is a new concept for robust protection against side impact that may be caused by much heavier vehicles. The rear rails (6a) have unique joints (J1-J21) (Fig. 7) with rear lateral cross-members (6b) that will help in retaining body integrity during rear collisions.
The design is adaptable in all the vehicles irrespective of their engine.

We claim;
1. A lightweight car having metal extrusion-based body with welded unique joints in a space frame configuration, having an electric motor integrated with a front wheel drive transmission system, said car comprises;
i. cross- car beam between B-pillars above floor level for enhanced side impact protection,
ii. front shock tower consisting of two extruded members laid out in the form of a compound L section, and
iii. notched joint of rear rail to rear seat cross-member for enhanced rear impact protection.
2. The car as claimed in claim 1, wherein the car is an electric vehicle.
3. The car as claimed in claim 1, wherein the body of the car is made preferably by aluminium extrusion members.
4. The car as claimed in claim 1, wherein the car frame is optionally covered with plastic or thin gage metallic exterior body panels.
5. The car as claimed in claim 1, wherein the car provides 21 welded joints (jl to j21) for optimal combination of rigidity and crashworthiness.
6. The car as claimed in claim 1, wherein the front shock tower is provided for mounting McPherson struts with coiled springs.
7. The car as claimed in claim 1, wherein the electric motor integrated with the front wheel drive transmission system permits driving at a fixed or variable gear ratios.
8. The car as claimed in claims 1 and 6, wherein the McPherson strut is mounted in an inclined manner without interference with the shock tower pillars.
9. The car as claimed in claim 1, wherein the L-section provides adequate area for supporting top plate for mounting the McPherson strut.
10. The car as claimed in claim 1, wherein the front wheel drive system is leveraged by coupling the DC motor with variable speed gear box with provision for clutch.
11. The car as claimed in claims 1 and 2, wherein the range of the vehicle can be easily extended with the help of hybrid configuration which is a combination of motor and an IC engine.
12. A method of manufacturing a lightweight car having metal extrusion-based body with welded unique joints in a space frame configuration, having an electric motor integrated with a front wheel drive transmission system, said method comprises steps of,
i. attaching cross- car beam between B-pillars above floor level for enhanced side impact protection,
ii. mounting front shock tower consisting of two extruded members laid out in the form of a compound L section with McPherson struts having coiled springs, and
iii. joining notched joint of rear rail to rear seat cross-member for enhanced rear impact protection to obtain the lightweight car.
13. The method as claimed in claim 12, wherein the body of the car is made preferably by aluminium extrusion members.
14. The method as claimed in claim 12, wherein the method provides about 21 welded joints (jl to j21) for optimal combination of rigidity and crashworthiness.
15. The method as claimed in claim 12, wherein the McPherson strut is mounted in an inclined manner without interference with the shock tower pillars.
16. The method as claimed in claim 12, wherein the front wheel drive system is leveraged by coupling the DC motor with variable speed gear box with provision for clutch.
17. The lightweight car and method of manufacturing the lightweight car of metal extrusion-based body with welded unique joints in a space frame configuration, having an electric motor integrated with a front wheel drive transmission system is substantially as herein above described with reference to the accompanying drawings.