WO2014098775A1

WO2014098775A1 - Automobile bodies and their manufacturing processes

Info

Publication number: WO2014098775A1
Application number: PCT/SK2013/000016
Authority: WO
Inventors: Lubomir ŠOOŠ; miloš MATÚŠ; František URBAN
Original assignee: Slovenská Technická Univerzita V Bratislave, Strojnícka Fakulta
Priority date: 2012-12-19
Filing date: 2013-12-17
Publication date: 2014-06-26

Abstract

The process of manufacturing car bodies is based on the following procedures. The first step is the casting of the complete independent front, central and rear parts of the car body under pressure in metallic moulds. The material used in casting is aluminium or composite light alloy materials. In the second step, the central part of the body, or its frame, is connected rigidly to the front and rear parts of the frame. The car body consists of the independently cast front, central and rear parts of the body, or the frames of these, made up of modifiable or replaceable modules, of aluminium, or aluminium foam, or from composite material made of light alloys containing at least one of the following components: aluminium, magnesium or manganese. The central part of the body or its frame is rigidly connected to the front part or its frame, and to the rear part and its frame. The modules of the independent complete front part of the body or its frame are either of a short or elongated type. The modules of the complete independent central part of the body, or just its frame, are of a two sea, four-seat or seven-seat type. The modules of the independent complete rear part of the body are those of a, saloon, hatchback, liftback or estate.

Description

Automobile Bodies and their Manufacturing Processes

Technical solution

The invention deals with a modular approach to the construction of the car body and the process of its manufacture and belongs to the area of the car industry.

Current state of the art

The body of the car is the synthesizing element of its whole. It brings together the requirements of functionality and safety on the one hand, and comfort on the other. Functionality, safety, strength and comfort increase the car's weight as well as fuel consumption. Continued competitiveness forces car producers to reduce fuel consumption, but increasing the weight and reducing fuel consumption in cars are demands which are apparently contradictory. This puts pressure on producers to search for new, non-traditional solutions. The weight of a mid-range car in 1960 was 2,400 kg, while in 2000 it was only 1 ,450 kg, which amounts to a reduction of 40%.

From the design and construction point of view, a motor vehicle consists of the power unit the chassis, and the body. Apart from the power unit, the body is the most important constructional unit. It is the part of the motor vehicle in which the space is reserved for the driver, passengers, power mechanism and load. In addition, it contains the loadbearing part of the car's structure, and, therefore, its construction must be sufficiently strong and tough, factors which significantly influence its safety and life cycle. Minimizing the body weight, while meeting safety and quality requirements, produces savings in the materials used and in fuel economy, all of which can be achieved by using high strength, lightweight materials. The minimum aerodynamic drag of the car influences its fuel consumption, and this can be reduced by the design of the car body. Visibility from the car is influenced by the design of the bonnet and the positioning of the window supports. Other important features are the easy and safe opening and closing of the doors and bonnet, as well as the comfortable and quick entry into and exit from the car. Other additional factors in car body design are the easy and rapid assembly and disassembly of damaged parts. At present, car body manufacturing is a complex process, as it includes about 800 components produced by forming technologies. The body sheets are cut, pressed, bent and subsequently joined by permanent joints, mostly by means of welding and gluing. The edges of the doors and bonnet are glued, as they need to have a smooth joint which does not require further processing. These processes of forming and joining car parts are highly demanding with regard to technological precision, costs and time. The total welding time of a car body is about 6 hours. A large amount of material and energy is used, which makes the manufacturing process more costly, and at the same time increases the body weight, which at present is within the range of 500-700 kg.

Car design significantly influences the driving properties of the vehicle, its ecology, manufacturing costs, and operation. As a whole, the car must bear longitudinal, transverse, diagonal, asymmetric, bending and torsion loads without any visible effects. Therefore, the materials used in car design should have the following properties: low weight, long life cycle, appropriate deformation behaviour, high strength and good ductility, good corrosion resistance, good welding properties and formability, as well as recycling properties.

At present the body parts are mostly made from steel plate by cutting, clipping, forming and subsequent welding. The number of welded parts amounts to several dozens or even several hundreds. This manufacturing process is highly demanding in terms of finance, logistics and time. Further finishing operations include processes such as zinc coating, degreasing, anti-corrosion protection, paint coating and spraying.

In cars, new devices are used to an ever greater extent to increase the safety and comfort of the passengers. In the interest of increasing passenger comfort, car dimensions are steadily increasing, as is the car's weight. On the other hand, there have been attempts to reduce fuel consumption. One of the solutions for fulfilling these contradictory requirements is to use lightweight materials with high strength in the car body design

The above-mentioned contradictions have afforded the industry the opportunity to address these problems by suitable technical means. These efforts have led to the following innovative car body and manufacturing process Subject of the invention

The above-mentioned problems can be solved by designing a new invention of car body and manufacturing process. Subject of the invention is the following process. In the first step, the whole front, central and rear parts of the car body are cast in metal moulds under pressure. The same process can be employed for just the frame of the front, central and rear parts of the car body. The material for casting is aluminium or composite materials containing aluminium and manganese or aluminium and magnesium, or all three of these compounds. The material for casting the individual parts of the car body and/or car body elements can have a foam structure. For example, aluminium foam can be used for the individual parts of the car body. During the process of casting the whole front, central and rear parts of the car body, or just their frames, it is possible to place high strength carbon fibres into the metallic form to ensure the directional sturdiness of the body. In this way it is possible to manufacture each particular modular body as a whole. In this module (body part) no welding or gluing is necessary, which saves a large amount of additional material normally used in traditional technologies.

Then, in the second step, the front and rear parts are rigidly connected to the central part by lock joints and/or fixed joining technologies, for example riveting, so that, in the event of damage, each part can be easily replaced in a garage.

In the next step, the doors and bonnet are attached to the joined front, central and rear parts of the body as a whole.

In a second variation to this innovative approach, it is possible to cast each individual module of the front, central or rear parts of the car and fit the body panels to the frame later. In the second step, the front and rear parts of the body are connected with the central part by a suitable riveting technology and/or lockable joints. In the next step, the additional parts, such as bumpers, metal sheets, roof and floor will be connected to the frames of the front, central and rear parts of the body by a click-clack technology. Then the doors and the bonnet will be assembled.

The modules of the front part of the body as a whole, or just the frame of the front part, are either of a short type, or of an elongated type, according to the scheme, see Figure 1. The modules of the independent complete central part of the body, or the frame of the central part, are of a 2-door/2-seat, 2-door/4-seat, 3-door/2- seat, 3-door/4-seat, 4-door/4-seat, 4-door/5-seat, 5-door/5-seat, 4-door extended/5- seat, and 5-door extended /7-seat type. The modules of the independent rear part of the body, or just the frame of the rear part of the body, are of a saloon, hatchback, liftback or estate type, see Figure 2.

The advantages of manufacturing along the lines of the innovation presented here are evidenced in the aforementioned effects. One substantial advantage is that by dividing the body into front, central and rear parts, the whole manufacturing process will be simplified. Each of these parts can have several variations, which can be combined and connected into a whole, enabling changes to the car type into modifications of saloon, hatchback, liftback or estate.

If the particular body elements are completed as a whole, so that neither welding nor gluing are necessary, a lot of additional materials which are normally used in these technologies will be saved,. Only the doors and the bonnet will have to be mounted.

If the particular body elements are in the form of the frame only, the additional parts, such as bumpers, sheets, the roof, the floor, and so forth, will be attached to it by means of a click-clack system. After that, the doors and the bonnet will be mounted. In the event of damage, the particular elements will be easy to replace. With the body cast in three pieces, we can considerably decrease the number of body components, reduce the weight of the vehicle and reduce the production costs. The manufacturing time would be lowered to a third, compared to the traditional methods, since during the casting process it is not necessary to have long breaks between the individual operations or assembly procedures. To minimize the weight of the body, it will be manufactured from lightweight and composite materials. It can be manufactured from foam aluminium reinforced with carbon fibres. Due to the porosity of the material, the weight can be reduced by one-half, compared to the weight of the car body made using the traditional methods of combining, forming, and welding, which means 350 kg of savings. The car body will be made by forming the metals, alloyed steel, tungsten alloys or molybdenum alloys, under pressure in moulds.

As these are made of high strength materials, they can be used repeatedly with an expected life span of 100,000 pressing cycles. The technology of frame casting has many advantages compared to the traditional method, for example greater savings in materials, since in the casting process an accurate amount of molten metal is used for each particular part, so that there is practically no waste, as there is in the cutting of metallic sheets. If a faulty piece is cast, it can easily be melted and used for producing another element. After solidifying, the cast frame is joined the front, central and rear parts, and is then ready for the paint shop and for further assembly. This also leads to savings in the manufacturing processes and, consequently, the lowering of the operational costs in terms of fuel savings. The technology of body casting provides the opportunity to change directional strength by using alternative combinations of materials, for example foam and classical materials, and by reinforcing the stress bearing elements, such as beams, with foamed structured materials. The bodies manufactured in this way have higher corrosion resistance, lower requirements for the finishing surfaces and longer durability. Body repairs are faster, as they can be achieved by changing the whole body part.

Description of the drawings

A car body made using the aluminium casting technology innovation is depicted in the drawings attached, where Figure 1 presents the scheme of possible combinations for creating different variations, and Figure 2 depicts a graphic model of the result.

Examples

It should be understood that the specific depictions of the invention are presented for illustrative purposes, not as a prescriptive technical solution. Experts in advanced technologies may be able to find various similar imitations of the specific technical models, but these imitations are covered by the patent rights which follow. For specialists in technology, it will not be difficult to design an optimal solution and therefore, such characteristics have not been worked out in detail.

Example 1

In this model of the innovation we describe the first manufacturing method of the car body using cast elements as a complete unit. In the first manufacturing step, the whole front, central and rear parts of the body are cast under pressure in metal moulds. The material used is aluminium. In the second step, the front and the rear parts of the body are rigidly connected to the central part by means of riveting technology. The last manufacturing step comprises mounting a bonnet onto the assembled front and the doors to the central and rear parts of the car body.

In another variation of the manufactured car body using the casting method, aluminium foam is used to make those elements which undergo the greatest stress.

In a further variation of this manufacturing process, the body parts under stress are made of a composite material containing at least two of the following elements: aluminium, magnesium, manganese.

Yet another variation of manufacturing by casting comprises placing high strength carbon fibres into the forms to reinforce the stressed parts of the body.

Example 2

In this example of the innovation under discussion, we describe the second method of manufacturing the car body with frames cast for the three parts of the assembled body. In the first step, the frame of the front, central and rear parts of the body are independently cast under pressure in metallic moulds. The material used is, for example, aluminium. During the second step, the central part of the body is rigidly connected to the front and rear parts. In the last step, the bonnet, bumpers, roof, floor components, body sheets, and finally doors are mounted onto the frame using a click-clack system.

In one variation of manufacturing car bodies using the casting method, stressed parts are manufactured from aluminium foam.

In another variation, stressed parts are made from composite materials containing at least two of the following elements: aluminium, magnesium and manganese.

In a further variation, materials with a high carbon fibre content are placed in a metallic mould to manufacture the stressed parts of the car body.

By means of the above-mentioned methods of high pressure casting of aluminium and its alloys with magnesium and/or manganese, or high carbon steel fibres respectively, car bodies consisting of three parts can be manufactured in the first instance as an independent front part of the body as a whole, as an independent central part of the body as a whole, and as an independent rear part as a whole. In the second case, the same method can be applied to manufacture the car bodies consisting of three parts as an independent complete frame of the front part, an independent complete frame of the central part and an independent complete frame of the rear part of the body. All the three independent parts, or only their frames, are made in the form of interchangeable and removable modules. The modules of the independent complete front part of the body, or only the frame of the front part, can be either of the short, or elongated type. The modules of the complete, independent central part of the body, or only the frame of the central part of the body, are of the two-door, four-door, or seven-seat type. The modules of the independent complete rear part of the body are of the saloon, hatchback, liftback or estate type. The complete car body is made using a permanent connection, whereby the central part of the body or its frame is rigidly connected to the front part of the body or its frame, and to the rear part of the body or its frame.

Industrial applicability

This car body and its innovative manufacturing process are used in the automotive industry.

Claims

C l a i m s

1. A car body manufacturing process, characterized in, that in the first step the complete front, central and rear parts of the body are cast under pressure in metal moulds. The materials used for casting are aluminium or composite materials containing aluminium. In the second step the front and the rear parts or the frame are rigidly connected to the central part or to its frame.

2. A car body manufacturing method, according to specification 1 above, characterized in, that the front and the rear part or their frames are rigidly connected to the central part or its frame by means of riveting and/or lock joints.

3. A car body manufacturing method, according to specifications 1 and 2 above, characterized in, that the material used for casting each particular body part and/or body component have a foam structure.

4. A car body manufacturing method, according to specifications 1 and 3 above, characterized in, that the material for casting is a composite material containing at least two of the components aluminium, magnesium, and manganese.

5. A car body manufacturing method, according to at least one of the specifications 1-4 above, characterized in, that when casting the independent complete front, central and rear parts of the body, or only their frames, high strength carbon fibres are placed into the forms to reinforce the stressed parts of the body.

6. A car body manufacturing method, according to at least one of the specifications 1-5 above, characterized in, that onto the connected front, central and rear parts of the car body, or onto just the frames of the front, central or rear parts of the body, the doors and the bonnet are mounted.

7. A car body manufacturing method, according to at least one of the requirements 1-5, characterized in, that the bumpers and body sheets are mounted onto the connected front, central and rear parts of the car body, or onto just the frame of the front, central and rear parts, by a click-clack system.

8. A car body manufacturing method, according to at least one of the requirements specifications 1-5 above, characterized in, that onto the connected front, central and rear parts of the car body, or onto the frames of the front, central or rear parts of the body, the roof and the floor components are mounted by a click-clack system.

9. The car body characterized in, that it consists of the cast, independent complete front, central and rear parts of the body, or only the frames of the front, central and rear parts of the body, made of interchangeable or removable modules, from aluminium or aluminium foam or composite material, containing at least one of the components aluminium, magnesium and manganese, where the central part of the body, or only its frame, is rigidly connected to the front and rear parts of the body or their frames.

10. The car body according to specification 9 characterized in, that the modules of the independent complete front part of the car body, or just the frame of the front part, are either of a short or elongated type. 1. The car body according to specification 9 characterized in, that the modules of the independent complete central part of the body, or of just the frame of the central part of the body, are of the two-door, four-door, or seven-seat type.

12. The car body according to specification 9 characterized in, that the modules of the independent complete rear part of the body, or just of its frame, are of the limousine, saloon, hatchback or estate type.

13. The car body according to at least one of the specifications 9-12 characterized in, that the modules of the independent complete front, central and rear parts of the body, or just the frames of the front, central and rear parts of the body with directional strength, include high strength carbon fibres.