DE102020206732B4 - Vehicle and method for producing a sheet steel component of the vehicle - Google Patents

Abstract

Vehicle (1), comprising a single-track two-wheel vehicle component (2) with a front wheel (5) and a rear wheel (6) and a two-track two-wheel vehicle component (3) with left and right vehicle wheels (25, 26), the single-track two-wheeler vehicle component (2) is arranged at the front of the vehicle (1) and the vehicle components (2, 3) are or can be detachably connected to one another, characterized in that in an operating state of the vehicle (1) in which the vehicle components (2, 3 ) are connected to one another, the single-track two-wheel vehicle component (2) is fastened in/on the two-track two-wheel vehicle component (3) in such a way that the rear wheel (6) of the single-track two-wheel vehicle component (2) is above and at a distance from a road surface (30 ) of the vehicle (1) is arranged, wherein the single-track two-wheel vehicle component (2) and the two-track two-wheel vehicle component (3) have at least one drive.

Description

The invention relates to a vehicle according to the preamble of claim 1 of the invention. According to claim 12 of the invention, the same further relates to a method for manufacturing a sheet steel component of said vehicle.

In conurbations, vehicle congestion is increasingly occurring simply because of excessive traffic density. This often happens spontaneously without warning and control systems are often not suitable or not available. Studies show that most urban journeys or commutes are made by just one person. According to the study, the average distances are predominantly less than 100 km. There is a need for a small vehicle that can be used flexibly in order to be able to react flexibly to, for example, sudden traffic jams. With regard to this, a large number of different concepts are already known.

That's how she describes it DE 10 2018 109 523 A1 a vehicle system which comprises a base vehicle with at least one drive means and at least one sub-vehicle which can be selectively decoupled and coupled from the base vehicle and an electric motor for autonomous locomotion by the base vehicle and an electric storage unit for supplying power to the electric motor. The basic vehicle and the sub-vehicle can be driven independently of one another. The sub-vehicle can be formed by an electric bicycle, an electric scooter or another known electrically powered means of transport for one or more people, such as a “Segway®” or an e-board. According to one embodiment, a sub-vehicle, here in the form of a “Segway®”, is supported in the base vehicle and electrically connected to the base vehicle in order to either charge the electric motor of the sub-vehicle or to supply electric current to an electric motor of the base vehicle.

US 2010/0 193 274 A1 describes a vehicle with a motorcycle component arranged at the rear of the vehicle and with a chassis component at the front of the vehicle, which are detachably connected to one another. Based on a two-track vehicle, the chassis component has two front wheels arranged coaxially with one another, whereas the single-track motorcycle component provides a rear wheel of the vehicle. For this purpose, the motorcycle is mounted in/on the chassis component in such a way that the front wheel of the motorcycle component is arranged above and at a distance from a road surface of the vehicle. The rider can choose between a three-wheeled vehicle and a motorcycle, with the three-wheeled vehicle being powered exclusively by the motorcycle component.

the JP 2005 - 119 349 A describes a two-track four-wheel vehicle, wherein at least one of the non-steered rear wheels is replaced by an electric scooter that is fixed to the vehicle and can be operated independently, which drives the vehicle or supplements the vehicle's internal drive. The electric scooter is designed as a two-wheeled two-wheeled vehicle in the manner of a “Segway®”.

the DE 10 2015 108 297 A1 describes a two-track four-wheel vehicle, wherein at least one of the rear wheels is replaced by a self-sufficiently operable unicycle with a handlebar and a self-drive, in particular with an electric motor. The self-propelled unicycle may be configured to propel the four-wheeled vehicle. If the unicycle is used separately from the vehicle, the vehicle is parked in a parking lot using a jack.

the DE 10 2016 220 673 A1 describes a two-track passenger car with an integrated electric motorcycle, which motorcycle is releasably attached to the front of the passenger car between two front wheels of the same. The electric motorcycle and the passenger car can be used independently to transport people. For this purpose, the passenger vehicle can be equipped with electric wheel hub motors at least on the front axle or have an internal combustion engine at the rear. At least in one operating state, only the electric motor of the motorcycle attached to the passenger car can be used to drive the passenger car.

the U.S. 1,145,682 A relates to a device which can be fitted to a motorcycle of any approved construction and in which an adjustable frame is provided at one end by a pair of wheels and is connected by means at the other end to the frame of the motorcycle so that the rear wheel thereof is in contact stands with the ground and a drive mechanism is arranged.

The object of the invention is to provide an alternative vehicle with regard to the prior art described above, which consists of a single-track vehicle component with a front and a rear wheel and a two-wheeled two-wheeled vehicle component having left and right vehicle wheels. Furthermore, the object of the invention is to create a method for producing a sheet steel component of said vehicle, which on the one hand does justice to the lightweight construction of the vehicle and on the other hand has improved deformation behavior, especially with regard to a possible accident event of the vehicle.

Starting from a vehicle comprising a single-track two-wheel vehicle component with a front wheel and a rear wheel and a two-track two-wheel vehicle component with a left and a right vehicle wheel, the single-track two-wheel vehicle component being arranged at the front of the vehicle and the vehicle components being detachably connected or connectable to one another , the stated object is initially achieved in that, in an operating state of the vehicle in which the vehicle components are connected to one another, the single-track two-wheel vehicle component is fastened in/on the two-track two-wheel vehicle component in such a way that the rear wheel of the single-track two-wheel vehicle component is above and is arranged at a distance from a driving surface of the vehicle, the single-track two-wheel vehicle component and the two-track two-wheel vehicle component having at least one drive..

This measure creates a simple and inexpensive vehicle in the manner of a three-wheeled scooter, which is particularly easy to handle and can be operated optimally.

Furthermore, the single-track two-wheel vehicle component and the two-track two-wheel vehicle component have at least one drive. This measure makes it possible to implement a wide variety of drive and utilization concepts.

The dependent claims describe preferred developments or refinements of the invention.

After that, the single-track two-wheeler vehicle component can be operated independently, for example in the event of a traffic jam, in order to reach the desired destination with minimal effort or more quickly.

The drive is preferably formed by an electric motor, which is assigned at least one electrochemical store for providing electrical energy for the electric motor.

In a further development of the invention, the single-track two-wheeler vehicle component has at least one/the steering device of the vehicle. That is to say, said steering device is set up not only to steer the same when the single-track two-wheeler vehicle component is operated separately, but also when the overall vehicle is operated with the two two-wheeler vehicle components assembled accordingly.

Provision is further preferably made for the two-wheeled two-wheeler vehicle component to have at least one seat element for at least one passenger of the vehicle in order to transport said passenger comfortably.

In order to create a safe vehicle, in particular a crash-proof vehicle, the two-wheeled two-wheeler vehicle component has a space frame or lattice frame structure on which the left and right vehicle wheels are mounted. Lattice frame structures are extremely stable and torsion-resistant with minimized material requirements and corresponding weight and are therefore particularly suitable for the application in question.

The lattice frame structure advantageously forms a driver's cab in order to transport the passenger safely.

In a further advantageous manner, the driver's cab formed has planking in order to further stiffen the driver's cab and thus increase the safety of the passenger and to protect the passenger from inclement weather.

The lattice frame structure is preferably formed by sheet steel components in the form of elongated hollow profiles, which are connected directly or extremely simply and inexpensively via node elements to form a supporting structure.

More preferably, the node elements are formed by sheet metal fold nodes that can be produced easily and inexpensively, in particular using a stamping and bending process.

As the invention also provides, the hollow profiles and/or node elements of the lattice frame structure are at least partially made from a hot-formed and press-hardened starting material in the form of a steel sheet with a structure comprising bainite, retained austenite and, if appropriate, martensite, said steel sheet having the following percentages by weight : 0.30 to 0.42% Carbon, 0.3 to 2.5% Manganese, 0.8 to 2.2% Silicon, up to 0.06% Aluminum, up to 0.5% chromium, nickel and molybdenum in total, up to 0.06% Niobium, up to 0.1% vanadium, up to 0.05% Titanium, 0.001 to 0.01% Boron, up to 0.01% Nitrogen, up to 0.01% Sulfur, up to 0.02% phosphorus, as well rest iron and impurities,

The relatively high carbon content of 0.30 to 0.42% can improve the stabilization of retained austenite in the steel material. In order to also be able to achieve good weldability of the steel material, the carbon content should not exceed 0.42%. In particular, the silicon content of 0.8 to 2.2% can stabilize retained austenite in the steel material, whereby the ductility of the steel material can be improved. In order to further improve the ductility of the steel material, the manganese content is also limited, so that the steel alloy contains a maximum of 2.5% manganese, but preferably only up to 1.0% (see below), in order to achieve a homogeneous structure and a to prevent adverse carbide formation in the steel material. By adding up to 0.06% niobium, grain refinement can be achieved, which can also contribute to improving ductility. The omission or the strong reduction of titanium delays the martensitic transformation in the press-hardening step and supports the bainitic transformation in the bainitising step. Boron serves to bind nitrogen, which also improves ductility. With the alloy components according to the invention, a steel material can be made available which is characterized by high strength and, at the same time, very high ductility. The steel material can advantageously be employed or used as a sheet steel component for the vehicle in question, in particular the hollow profiles and/or node elements of the lattice frame structure.

The steel alloy preferably contains chromium, nickel and/or molybdenum, with the sum of chromium, nickel and/or molybdenum preferably being less than 0.5%, preferably less than 0.35%. The steel alloy therefore preferably has only a very small proportion of chromium, nickel and molybdenum, as a result of which the amount of more expensive alloying elements in the steel alloy can be reduced.

After hot forming, the steel material preferably has a yield point Re ≥ 780 MPa. In the case of a material, the yield point characterizes the stress up to which the material shows almost no permanent plastic deformation under moment-free and uniaxial tensile loading. This means that the material deforms, but returns to its original shape after the stress is removed. The deformation remains reversible or elastic.

The bending angle of the steel material after hot working is preferably equal to or larger than 75°. The elongation at break A ₅₀ of the steel material is preferably equal to or greater than 14%. Due to this high bending angle and/or the high elongation at break, the steel material can have a particularly high ductility.

Furthermore, after hot forming, the steel material is characterized by high strength, with the steel material preferably having a tensile strength Rm≧1180 MPa. The tensile strength determines the maximum mechanical tensile stress that the steel material can withstand. The steel material thus has a higher tensile strength with at least the same ductility as the cold-forming grades commonly used, such as DP780 or DP980.

A hollow profile and/or node element of the lattice frame structure made from such a steel material has a low weight, so that it has a high potential for lightweight construction. On the other hand, such a hollow profile and/or node element has a high strength combined with a very high ductility, so that the behavior of the lattice frame structure can be improved in the event of an accident of the vehicle.

As far as the method for producing a sheet steel component for the vehicle in question is concerned, it is preferably provided that in a chronological process sequence in a first process step a starting material runs through a trimming and cold forming step by roll profiling and/or bending and/or forming in a second process step the pre-material undergoes a first heat treatment step (= austenitization step), in a third process step the pre-material is subjected to a quenching process step, in a fourth process step the pre-material undergoes a second heat treatment process (= bainitization step), in a fifth process step (= press-hardening step) the material is press-hardened and in a sixth process step, the sheet steel component is subjected to a third heat treatment step (=partitioning heat treatment step). In a seventh step, a further trimming operation to the component size and/or component contour and/or for the introduction of holes can take place.

Due to the very high deformability, the sheet steel component can be subjected to a shaping process, in particular a cold forming process, in a further process step after the hot forming process described above. As a result, advantageously more complex components, in particular said hollow profiles and/or junction elements, can be produced and/or additionally hardened areas can be set in the component by strain hardening.

• 1 äußerst schematisch das erfindungsgemäße Fahrzeug in einer perspektivischen Ansicht von schräg vorn, umfassend eine einspurige Zweiradkomponente sowie eine zweispurige Zweiradkomponente (Variante 1),
• 2 eine äußerst schematische Darstellung der separaten Nutzung der einspurigen Zweiradkomponente als Fortbewegungsmittel,
• 3 die einspurige Zweiradkomponente in einer äußerst schematischen Einzeldarstellung derselben,
• 4 eine perspektivische Darstellung eines in einer Radgabel aufgehängten Vorderrades der einspurigen Zweiradkomponente nach 3,
• 5 einen Horizontalschnitt eines Trittbrettes der einspurigen Zweiradkomponente,
• 6 eine äußerst schematische Darstellung eines Koppelmechanismus zur Kopplung der Radgabel mit einer Steuerstange des Fahrzeugs während eines Koppelvorgangs,
• 7 den Koppelmechanismus im gekoppelten Zustand der Radgabel mit der Steuerstange,
• 8 eine Seitenansicht der beiden Zweiradkomponenten nach 1 in einer voneinander separierten Darstellung derselben,
• 9 die Einzelheit „Z“ nach 8 mit der Darstellung eines Fügebereiches einer Gitterrahmenstruktur der zweispurigen Zweirad-Komponente,
• 10a-c drei Beispiele eines Knotenelements der Gitterrahmenstruktur,
• 11 eine Seitenansicht der beiden Zweiradkomponenten des Fahrzeugs nach 1 im Zusammenbau derselben,
• 12 eine äußerst schematische Funktionsdarstellung des Zusammenbaus der beiden Zweiradkomponenten,
• 13 die Einzelheit „Y“ nach 12,
• 14 eine äußerst schematische Darstellung eines Verbindungselements zwischen der Radgabel und der Steuerstange als zusätzliches Mittel zum Einsatz der Steuerstange bei der Nutzung des Gesamt-Fahrzeugs als Fortbewegungsmittel,
• 15 äußerst schematisch eine zweite Variante des erfindungsgemäßen Fahrzeugs in einer perspektivischen Ansicht von schräg vorn,
• 16 eine vorteilhafte Weiterbildung des Fahrzeug nach 15,
• 17 ein Prozessschaubild, welches schematisch eine Prozessabfolge der Warmumformung zur Herstellung eines kaltgeformten und pressgehärteten Stahlblechbauteils für das erfindungsgemäße Fahrzeug zeigt, und
• 18 einen exemplarischen Verlauf der Temperatur „T“ in °C über der Zeit „t“ bei einer derartigen Warmumformung.

The invention is explained in more detail below with reference to the exemplary embodiments shown schematically in the drawings. However, it is not limited to these, but covers all configurations defined by the patent claims. For the purposes of the present description, the usual direction of travel of a motor vehicle should be indicated with "-x"("minusx"), the direction opposite to its usual direction of travel with "+x"("plusx"), starting from the usual direction of travel (-x ) the horizontal direction transverse to the x-direction to the right as seen with "+y", starting from the usual direction of travel (-x) the horizontal direction transverse to the x-direction to the left as seen with "-y", the direction in the vertical perpendicular to the x-direction seen upwards with "+z", and the direction in the vertical perpendicular to the x-direction seen downwards with "-z". This notation of the spatial directions in Cartesian coordinates corresponds to that in the Coordinate system commonly used in the automotive industry.In addition, terms such as "front", "rear", "top""bottom" and terms with similar meanings including the terms "right" and "left" are used in the manner in which they are used to designate directions g are commonly used on a motor vehicle. Show it:

• 1 extremely schematically the vehicle according to the invention in a perspective view obliquely from the front, comprising a single-track two-wheeler component and a two-track two-wheeler component (variant 1),
• 2 an extremely schematic representation of the separate use of the single-track two-wheeler component as a means of locomotion,
• 3 the single-track two-wheeler component in an extremely schematic individual representation of the same,
• 4 a perspective view of a front wheel suspended in a wheel fork of the single-track two-wheeler component 3 ,
• 5 a horizontal section of a running board of the single-track two-wheeler component,
• 6 an extremely schematic representation of a coupling mechanism for coupling the wheel fork to a control rod of the vehicle during a coupling process,
• 7 the coupling mechanism in the coupled state of the wheel fork with the control rod,
• 8th a side view of the two bicycle components 1 in a separate representation of the same,
• 9 the detail "Z" after 8th with the representation of a joining area of a lattice frame structure of the two-track two-wheeler component,
• 10a-c three examples of a node element of the lattice frame structure,
• 11 a side view of the two two-wheel components of the vehicle 1 in the assembly of the same
• 12 an extremely schematic functional representation of the assembly of the two bicycle components,
• 13 the detail "Y" after 12 ,
• 14 an extremely schematic representation of a connecting element between the wheel fork and the control rod as an additional means of using the control rod when using the entire vehicle as a means of locomotion,
• 15 extremely diagrammatically a second variant of the vehicle according to the invention in a perspective view obliquely from the front,
• 16 an advantageous further development of the vehicle 15 ,
• 17 a process diagram which schematically shows a process sequence of hot forming for the production of a cold-formed and press-hardened sheet steel component for the vehicle according to the invention, and
• 18 an example of the temperature "T" in °C over time "t" for such a hot forming process.

This in 1 Vehicle 1 shown comprises a one-track two-wheeler vehicle component 2 and a two-track two-wheeler vehicle component 3, which are detachably connected to one another. The single-track two-wheeled vehicle component 2 is designed in the manner of a scooter known per se and as shown in FIG 2 shown independently operable by a passenger 4 or a third party.

The single-track two-wheel vehicle component 2 has according to 3 and 4 a steerable front wheel 5 and a rear wheel 6. The steerable front wheel 5 is rotatably mounted in a wheel fork 7 known per se. The wheel fork 7 is rotatably mounted on a base structure 8 of the two-wheeled vehicle component 2 . According to 5 the base structure 8 has a footboard 9 on which the rear wheel 6 is rotatably mounted about an axis of rotation 10 . The passenger 4 can stand on the running board 8 (cf. 2 ). At the wheel fork 7 is a steering device 11 with a known control rod 11 a releasably attached or attachable.

The detachability of the steering device 11 or control rod 11a is by means of one in the 6 and 7 Coupling mechanism 12 shown schematically causes. According to this exemplary embodiment, the coupling mechanism 12 has a positive-locking element 13 that can be fixed in a coupling position and is arranged on a receiving tube 14 of the wheel fork 7 accommodating the control rod 11a. The form-fitting element 13 is presently formed by a spring ring known per se, which positively engages in a form-fitting counter-element 15 in the form of an annular groove. To secure the positive connection, a first tubular securing element 17 is provided which is subjected to spring force by means of compression spring(s) 16 and secures the spring washer in a latching position within the annular groove from the radial outside. In addition, a spring-loaded second tubular securing element 19 is provided by means of compression spring(s) 18, which secures the spring ring from radially inward in a release position by urging it radially outward (not shown in the drawing). In the last-described case, the first securing element 17 is pulled out of its securing position by means of a pulling element 20, for example a Bowden cable. In order to ensure reliable functioning of the spring washer, the annular groove and the first securing element 17 have bevels 21 .

The control rod 11a and the receiving tube 14 of the wheel fork 7 preferably have cross sections which correspond to one another and which ensure a steering torque transmission. Said cross-sections can be formed, for example, by non-round cross-sections, such as oval cross-sections, or by polygonal cross-sections (not shown in the drawing). Alternatively, a mechanical fastening element known per se can also be provided for steering torque transmission, for example a fastening tion screw, which passes through corresponding bores of the control rod 11a and the receiving tube 14 of the wheel fork 7 or a key arrangement known per se (not shown in the drawing).

The two-wheeled two-wheeler vehicle component 3 has a lattice frame structure 22 which is formed from a plurality of sheet steel components in the form of elongated hollow profiles 23 . The hollow profiles 23 are connected directly or via node elements 24 to form a load-bearing structure, in particular glued and mechanically joined (cf. 1 , 8-10c ). the 8th shows an example of such a joint connection using node elements 24. The 10a-c also show, merely by way of example, differently designed node elements 24 in the form of so-called sheet metal folding nodes, which are accordingly also made from sheet metal, in particular sheet steel.

Again 8th can be seen further, a left and a right vehicle wheel 25, 26 are rotatably mounted on the lattice frame structure 12 of the two-wheeled vehicle component 3 with two wheels. In addition, the lattice frame structure 12 forms a driver's cab 27 in which a seat element 28 for at least one passenger 4 of the vehicle 1 is arranged. The driver's cab 27 is adjoined to the rear by a region of the lattice frame structure 12 that can be formed into a loading area 29 in the manner of a vehicle 1 with an open loading area.

Like the one in particular 1 , 11 until 13 can be seen further, when the two vehicle components 2, 3 are assembled, the single-track two-wheeled vehicle component 2 is arranged in a front receiving area of the two-tracked two-wheeled vehicle component 3 and is detachably connected to it in such a way that the rear wheel 6 of the single-tracked two-wheeled vehicle component 2 is above and spaced from a timetable 30 of the vehicle 1 is arranged. This is made possible by the 12 and 13 extremely diagrammatically illustrated rail system 31 of the two-wheeled two-wheeled vehicle component 3, which allows the rear area of the two-wheeled two-wheeled vehicle component 2 together with the rear wheel 6 of the same to be transferred to said distance from the road surface and fixed there by means of known, detachable fastening elements (not shown in the drawing). to fix the two-wheeled two-wheeled vehicle component 3 . Said detachable fastening elements can be formed, for example, by quick-release devices known per se. As far as the rail system 31 is concerned, it preferably comprises two guide rails 32 , one guide rail 32 being arranged on each side of the single-track two-wheeler vehicle component 2 . More preferably, a guide element (not shown in the drawing), for example a guide pin, of the single-track two-wheeler vehicle component 2 is slidably guided in each guide rail 32 .

In order to make the control rod 11a of the steering device 11 of the single-track two-wheeler vehicle component 2 usable for the entire vehicle 1, the same is an in 14 schematically shown, known per se associated universal joint 33. As a result, the control rod 11a can assume a comfortable inclined position relative to a passenger 4 sitting on the seat element 28 of the two-wheeled two-wheeler vehicle component 3 .

After all, the vehicle 1 forms a three-wheeled cabin scooter, so to speak, with the steering device 11 for the separately operable single-track two-wheeled vehicle component 2 designed as a scooter simultaneously serving as a steering device 11 for the entire vehicle 1 . The single-track two-wheeled vehicle component 2 designed as a scooter is preferably designed as an electric scooter and therefore has at least one electric motor, not shown in the drawing, together with an electrochemical storage device (battery) for driving the front wheel 5 of the single-track two-wheeled vehicle component 2 . The single-track two-wheeler vehicle component 2 , which is now designed as an electric scooter, accordingly also drives the entire vehicle 1 .

In addition to the preferred drive concept described above, alternative drive concepts can of course also be used, which are also covered by the invention. For example, it can be provided that the two-wheeled two-wheeler vehicle component 3 also has at least one electric motor together with an electrochemical storage device for driving at least one of its vehicle wheels 25, 26. That is, when the vehicle 1 is in operation, both vehicle components 2, 3 can provide drive power both individually and in combination (not shown in the drawing).

Furthermore, it can be provided that the single-track two-wheeler vehicle component 2 designed as a scooter does not have its own drive, but can only be operated separately and manually. In this case, the two-wheeled two-wheeler vehicle component 3 provides the electric drive of the vehicle 1, weighed The single-track two-wheeled vehicle component 2 provides the steering device 11 for the vehicle 1 (not shown in the drawing).

The embodiment after 15 differs from the embodiment 1 essentially in that the loading area area 29 is not intended to form an open loading area, but rather to form an enclosed loading area. In view of this, according to 16 a planking 34 is provided, which advantageously stiffens the formed driver's cab 27 and, on top of that, increases the safety of the passenger and protects the same, together with the load, from inclement weather.

As far as the hollow profiles 23 and/or node elements 24 of the lattice frame structure 22 are concerned, these are at least partially made from a hot-formed and press-hardened starting material in the form of a steel sheet with a structure comprising bainite, retained austenite and optionally martensite. Said steel sheet has the following components in percent by weight: 0.30 to 0.42% Carbon, 0.3 to 2.5% Manganese, 0.8 to 2.2% Silicon, up to 0.06% Aluminum, up to 0.5% chromium, nickel and molybdenum in total, up to 0.06% Niobium, up to 0.1% vanadium, up to 0.05% Titanium, 0.001 to 0.01% Boron, up to 0.01% Nitrogen, up to 0.01% Sulfur, up to 0.02% phosphorus, as well rest iron and impurities.

The advantageous properties resulting from the above steel alloys of the steel sheet used to produce the hollow profiles 23 and/or node elements 24 for the lattice frame structure 22 have already been described in detail above.

In 17 The process sequence of such a hot forming for the production of a cold-formed and press-hardened sheet steel component for the vehicle 1 is shown schematically. In view of this, the method for producing a sheet steel component from said steel alloys for the vehicle 1 in question is essentially characterized in that in a chronological process sequence in a first process step, a starting material of such a steel alloy first undergoes a trimming and cold forming step by roll profiling and/or bending and/or forming "Ku" goes through. In a second process step, the starting material goes through a first heat treatment step "Ac" (= austenitization step). In a third process step, the starting material is subjected to a quenching process step "A _s ". In a fourth process step, the starting material goes through a second heat treatment process "Bs" (= bainitising step). In a fifth process step "P" (= press hardening step) the material is press hardened and in a sixth process step the sheet steel component is finally subjected to a third heat treatment step "Pw" (= partitioning heat treatment step). In a seventh step, a further trimming operation "Bo" can be carried out to the component dimensions and/or component contour and/or for the introduction of holes.

Due to the very high formability, the sheet steel component can be subjected to a further process step after the hot forming process described above, a shaping process, in particular a cold bending process and cold forming process "Kbu". As a result, advantageously more complex components, in particular said hollow profiles 23 and/or node element 24, can be produced and/or additionally hardened areas can be adjusted by strain hardening in the relevant component.

Alternatively, the third heat treatment step "Pw" can also take place after assembly of the space frame structure 22 and, for example, during painting of the vehicle.

18 shows an example of the progression of the temperature "T" in °C over the time "t" for such a hot forming process. In a first heat treatment process step “Ac”, the preformed sheet steel blank is preferably heated to a process temperature “T _A ” within a time “Δt _A ” above the material-specific austenitization temperature “A _c3 ”, for example to around 900°C. The quenching process "A _s " is preferably performed at a cooling rate of more than 27°C/s for a period of time "Δt _s " so that rapid cooling of the preformed steel sheet blank can occur before the second heat treatment process "B _s " starts. The second heat treatment process “B _s ” preferably starts when the workpiece has a temperature “T _in ” lower than the bainite start temperature “B _start ” and greater than the bainite finish temperature “B _fin ”. The holding phase “Δt _B ” during the second heat treatment step is designed in such a way that a microstructure can essentially be transformed into bainite, retained austenite and martensite in the base material. A ferrite area "Fer", a bainite area "Ba" and a pearlite area "Per" can form. For this purpose, the holding phase “Δt _B ” can be between 10 seconds and 30 minutes, preferably between 30 seconds and 6 minutes.

After completion of the second heat treatment step, quench hardening can take place immediately afterwards during the press hardening step "P", in which the structure formed from bainite and possibly residual austenite is "frozen" in the steel sheet. If the conversion is incomplete, ie if the second heat treatment step “Δt _B ” is selected to be shorter, an increased proportion of martensite can also form during the press hardening process, which can increase the hardness of the steel material. During the press hardening step "P", the workpiece continues to cool down to "T _off " within the time "Δt _H ".
Air cooling continues for a time “Δt _LK ” until the beginning of the third heat treatment step “P _w ” and/or the further trimming operation “B _o ”.

In a third heat treatment step "P _w ", a partitioning heat treatment step, the frozen structure consisting essentially of bainite, stabilized retained austenite and possibly martensite is partitioned within the time period "Δt _p ", ie stabilized by uniform redistribution of the carbon. Temperatures can range in temperature greater than 100-225°C for 30 seconds to 60 minutes, preferably greater than 150-200°C for 5-30 minutes.

The removal temperature "T _from " can be in a temperature range of -10% to +30% around the material-specific martensite finish temperature "M _f " and below the martensite start temperature "M _s ", at which austenite transformation occurs to martensite is mostly complete. It has proven to be advantageous to stop the press-hardening step immediately when the martensite finish temperature "M _f " is reached and to continue cooling the component in air or at a much lower cooling rate so that the thin steel sheet component can relax. As a result, the press hardening time can be kept very short, which advantageously increases the cycle time.

Reference List

1

vehicle

2

single-track two-wheeled vehicle component

3

dual track two wheeler vehicle component

4

passenger

5

front wheel

6

rear wheel

7

wheel fork

8th

base structure

9

running board

10

axis of rotation

11

steering device

11a

control rod

12

coupling mechanism

13

interlocking element

14

pickup tube

15

form-fit counter-element

16

compression spring

17

first security element

18

compression spring

19

second security element

20

tension element

21

leading edge

22

lattice frame structure

23

hollow profile

24

node element

25

vehicle wheel

26

vehicle wheel

27

driver's cabin

28

seat element

29

bed area

30

timetable

31

rail system

32

guide rail

33

universal joint

34

planking

Ac

austenitizing step

Ac3

material-specific austenitization temperature

ace

quenching process step

ba

bainite area

Bfin

Bainite finish temperature

Bs

bainitization step

Bstart

Bainite start temperature

bo

crop operation

Fer

ferrite area

Mf

Martensite Finish Temperature

Ms

Martensite Start Temperature

P

press hardening step

By

perlite area

T

temperature

t

time

ta

Process temperature during the austenitizing step "A _c "

dew

Workpiece temperature at the end of the press hardening step "P"

thein

Workpiece temperature during the bainitising step "B _s "

ΔT

Temperature difference between the martensite start temperature "M _s " and the workpiece temperature during the bainitising step "B _s "

ΔtA

Duration of the austenitizing step "Ac"

ΔtB

Holding phase during the bainitisation step “B _s ”

ΔtH

Duration of the press hardening step "P"

ΔtLK

Duration of air cooling during depositing step "A _b "

Δtp

Duration of partitioning heat treatment step "P _w "

Δts

Duration of the quenching process "A _s "

Claims (13)

Vehicle (1), comprising a single-track two-wheel vehicle component (2) with a front wheel (5) and a rear wheel (6) and a two-track two-wheel vehicle component (3) with left and right vehicle wheels (25, 26), wherein the Single-track two-wheeler vehicle component (2) is arranged at the front of the vehicle (1) and the vehicle components (2, 3) are or can be detachably connected to one another, characterized in that in an operating state of the vehicle (1) in which the vehicle components (2, 3 ) are connected to one another, the single-track two-wheel vehicle component (2) is fastened in/on the two-track two-wheel vehicle component (3) in such a way that the rear wheel (6) of the single-track two-wheel vehicle component (2) is above and at a distance from a road surface (30 ) of the vehicle (1) is arranged, wherein the single-track two-wheel vehicle component (2) and the two-track two-wheel vehicle component (3) have at least one drive. Vehicle (1) after claim 1 , characterized in that the single-track two-wheel vehicle component (2) can be operated independently. Vehicle (1) after claim 1 , characterized in that the drive is formed by an electric motor, which is associated with at least one electrochemical storage. Vehicle (1) according to one of the preceding claims, characterized in that the single-track two-wheel vehicle component (2) has at least one steering device (11) of the vehicle (1). Vehicle (1) according to one of the preceding claims, characterized in that the two-wheeled two-wheeler vehicle component (3) has at least one seat element (28) for at least one passenger (4) of the vehicle (1). Vehicle (1) according to one of the preceding claims, characterized in that the two-wheeled two-wheeled vehicle component (3) has a lattice frame structure (22) on which the left and right vehicle wheels (25, 26) are mounted. Vehicle (1) after claim 6 , characterized in that the lattice frame structure (22) forms a driver's cab (27). Vehicle (1) after claim 7 , characterized in that the formed driver's cab (27) has a planking (34). Vehicle (1) according to one of Claims 6 until 8th , characterized in that the lattice frame structure (22) is formed by sheet steel components in the form of elongated hollow profiles (23) which are connected directly or via node elements (24) to form a supporting structure. Vehicle (1) after claim 9 , characterized in that the node elements (24) are formed by sheet metal folding nodes. Vehicle (1) after claim 9 or 10 , characterized in that the hollow profiles (23) and/or node elements (24) of the lattice frame structure (22) are produced at least partially from a hot-formed and press-hardened starting material in the form of a thin steel sheet with a structure containing bainite, retained austenite and optionally martensite, wherein said steel sheet has the following percentages by weight: 0.30 to 0.42% Carbon, 0.3 to 2.5% Manganese, 0.8 to 2.2% Silicon, up to 0.06% Aluminum, up to 0.5% chromium, nickel and molybdenum in total, up to 0.06% Niobium, up to 0.1% vanadium, up to 0.05% Titanium, 0.001 to 0.01% Boron, up to 0.01% Nitrogen, up to 0.01% Sulfur, up to 0.02% phosphorus, as well rest iron and impurities, Method for producing a sheet steel component of the vehicle (1) according to one of Claims 10 until 12 , in which, in a chronological process sequence, in a first process step, a starting material goes through a trimming and cold forming step by roll profiling and/or bending and/or forming, in a second process step the starting material goes through a first heat treatment step (Ac), in a third process step the starting material undergoes a Quenching process step (A _s ) is subjected, in a fourth process step the starting material undergoes a second heat treatment process (Bs), in a fifth process step (P) the material is press-hardened and in a sixth process step the sheet steel component is subjected to a third heat treatment step (Pw). procedure after claim 12 , characterized in that a further trimming operation (Bo) takes place in a seventh step.

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