Rear side structure inner for a pickup truck

Abstract

Rear side structure inner (10) for a pickup truck frame (1) manufactured by stamping an inner blank (10b) – said rear side structure inner (10) comprising a C- pillar, a belt rail, a wheelouse inner and a D-pillar portion (101, 102, 103, 104,).

Description

[0001] Rear side structure inner for a pickup truck

[0002]

[0001] The present invention relates to a pickup truck and more specifically to the rear side structure of a pickup truck.

[0003]

[0002] Pickup trucks generally comprise a frame assembly having in the front a cab for carrying passengers and in the rear a cargo box, also called bed, for carrying cargo.

[0004]

[0003] The cab typically includes on each side a cab side structure comprising one or two doors, according to the number of seat rows, said side structures being bordered on each side by structural pillars that play an important role in guaranteeing the rigidity and ensuring the safety of the vehicle.

[0005]

[0004] The cargo box typically includes a base panel surrounded by four upstanding walls to form a container. The walls include two side walls, a front wall and a rear wall. The rear wall may be pivotably mounted to provide a tailgate facilitating the insertion or removal of articles in the cargo box. Each side wall includes a wheel casing which protrudes into the cargo box and which is destined to be placed above a rear wheel of the vehicle.

[0006]

[0005] The cab side structure and the cargo box side walls are made of several individual parts that are manufactured separately and then assembled together. The aim of the present invention is to simplify the overall manufacturing process of a pickup truck by providing for a simplified side structure integrating the rear of the cab side structure and the cargo box side walls, in particular a simplified rear side structure inner. The present invention also allows to optimize the material usage, the resistance and overall manufacturing costs.

[0007]

[0006] The current invention provides for a side structure consisting of an inner part made by stamping an individual blank of metallic material. For example, said individual blank is a tailor welded blank, or a tailor rolled blank.

[0008]

[0007] The use of tailor welded blanks for automotive parts is known in the industry, as illustrated for example by patent EP2056979 or for example by patent EP2736672. The use of tailor rolled blanks for automotive parts is known in the industry, as illustrated for example by patent EP2025771 .

[0008] The object of the present invention is achieved by providing a rear side structure inner according to claim 1 , optionally comprising the features of claims 2 to 6 taken individually or according to any possible combination. A further object of the present invention is a rear side structure assembly according to claims 7 or 8. A further object of the present invention is a pickup truck according to claim 9.

[0009]

[0009] Other aspects and advantages of the invention will appear upon reading the following description, given by way of example, and made in reference to the appended drawings, which are in no way limitative, wherein:

[0010] -Figure 1 is an overall perspective view of the inner structural frame of a pickup truck.

[0010]

[0011] -Figure 2a is a perspective view of an embodiment of a right hand side rear side structure inner according to the invention and figure 2b a view of the corresponding inner blank.

[0011]

[0012] -Figure 3 is a perspective view of an embodiment of the elements making up a right hand side rear side structure outer.

[0012]

[0013] In the following descriptions and claims, the directional terms are defined according to the usual directions of a mounted vehicle.

[0013]

[0014] In particular, the terms “top”, “up”, “upper”, “above”, “bottom”, “low”, “lower”, “below” etc. are defined according to the elevation direction of a vehicle. The terms “front”, “back”, “rear”, “front”, “forward”, backward” etc. are defined according to the longitudinal direction of a vehicle, i.e. the direction in which the vehicle moves forward when following a straight line. The terms “left”, “right”, “transverse”, etc. are defined according to the orientation parallel to the width of the vehicle. The terms “steering side” and “passenger side” referred to the general transversal direction respectively of where the driver and the passenger sit in a vehicle. Such directions will naturally be different according to whether the vehicle is a left-hand or right-hand drive vehicle. The terms “inner”, “outer” are to be understood according to the width direction of the vehicle: the “inner” is closest to the central axis of the vehicle, i.e. closest to the inside of the vehicle, whereas the “outer” is located further away from said central axis of the vehicle, in effect closer to the outside of the vehicle. The same applies to the terms “distal” and “central”: the “distal” part is located closest to the outside of the vehicle and the “central” part closest to the center of the vehicle. The term “horizontal” refers to the orientation of the plane comprising the longitudinal and the transverse directions. The term “vertical” refers to any orientation comprising the elevation direction.

[0014]

[0015] In the following figures, the orientations and spatial references are all made using an X, Y, Z coordinates referential, wherein Z is the elevation direction of the vehicle, X is the longitudinal direction of the vehicle and Y is the transverse direction of the vehicle. The X axis is oriented such that the X coordinates increase in the front to rear direction, i.e. a position located further back in the vehicle will have a higher X coordinate than a position located further in the front of the vehicle. The referential is represented in each figure. When the figure is a 2D flat representation, the axis which is outside of the figure is represented by a dot in a circle when it is pointing towards the reader and by a cross in a circle when it is pointing away from the reader, following established conventions.

[0015]

[0016] By “substantially parallel” or “substantially perpendicular” it is meant a direction which can deviate from the parallel or perpendicular direction by no more than 15°.

[0016]

[0017] A steel sheet refers to a flat sheet of steel. It has a top and bottom face, which are also referred to as a top and bottom side or as a top and bottom surface. The distance between said faces is designated as the thickness of the sheet. The thickness can be measured for example using a micrometer, the spindle and anvil of which are placed on the top and bottom faces. In a similar way, the thickness can also be measured on a formed part.

[0017]

[0018] By average thickness of a part, or of a portion of a part, it is meant the overall average thickness of the material making up the part after it has been formed into a 3-dimensional part from an initially flat sheet.

[0018]

[0019] Tailor welded blanks are made by assembling together by any known assembly technique, several sheets or cut-out blanks of steel, known as subblanks, in order to optimize the performance of the part in its different areas, to reduce overall part weight, to reduce overall part cost and material scrap and to simplify the production process.

[0020] A flexible blank is a type of tailor welded blank including regions wherein at least part of the connection between the different sub-blanks is not rigid, allowing the sub-blanks to move in different directions during the forming operation in the corresponding regions.

[0019]

[0021] By opposition to a tailor welded blank, a monolithic blank refers to a blank which consists of one single sub-blank, without several sub-blanks being combined together.

[0020]

[0022] A tailor rolled blank is a blank having multiple sheet thicknesses obtained by differential rolling during the steel sheet production process.

[0021]

[0023] A patched blank is a blank comprising a main blank to which is attached at least one further reinforcing blank, known as a patch, designed to locally increase the thickness and mechanical resistance of said blank. Said patch can be fixed to the main blank by spot welding, laser stitch welding, adhesive bonding, clinching or any other known assembly technique. The main blank can be a tailor welded blank, a tailor rolled blank or a combination of both. In the case of tailor welded blanks in which the subblanks are assembled together by butt to butt welding, a patch can be advantageously applied to the welded area in order to increase the mechanical resistance of the welded area.

[0022]

[0024] The ultimate tensile strength, the yield strength and the elongation are measured according to ISO standard ISO 6892-1 , published in October 2009. The tensile test specimens are cut-out from flat areas. If necessary, small size tensile test samples are taken to accommodate for the total available flat area on the part.

[0023]

[0025] The bending angle is measured according to the VDA-238 bending standard. For the same material, the bending angle depends on the thickness. For the sake of simplicity, the bending angle values of the current invention refer to a thickness of 1.5mm. If the thickness is different than 1.5mm, the bending angle value needs to be normalized to 1.5mm by the following calculation where a1.5 is the bending angle normalized at 1.5mm, t is the thickness, and at is the bending angle for thickness t:

[0024]

[0026] a1.5 = (at x t) / 1.5

[0027] Cold stamping is a forming technology for metals which involves shaping a metallic sheet into a formed part by pressing it between an upper and lower die, called the cold stamping tool. For example, the cold stamping tool has a blank holder which allows to hold the metallic sheet on its sides. For example, the cold stamping tool consists of several steps, each involving an upper and lower die to produce complex shapes and I or to perform further operations such as punching holes in the part or trimming its sides. Other cold forming technologies exist such as for example roll forming, which involves bending a continuous sheet between a successive set of rolls, simple bending which involves simply bending a sheet of steel using a press and an upper and lower bending tool etc.

[0025]

[0028] Hot stamping is a forming technology for steel which involves heating a blank of steel, or a preformed part made from a blank of steel, up to a temperature at which the microstructure of the steel has at least partially transformed to austenite, forming the blank or preformed part at high temperature by stamping it and simultaneously quenching the formed part to obtain a microstructure having a very high strength, possibly with an additional partitioning or tempering step in the heat treatment.

[0026]

[0029] A complex hot stamping process is a particular type of hot stamping process including at least one stamping step and consisting of at least two process steps performed at high temperature, above 300°C. For example, a complex process can involve a first stamping operation and a subsequent hot trimming operation, so that the finished part, at the exit of the hot stamping process, does not need to be further trimmed. For example, a complex process can involve several successive stamping steps in order to manufacture parts having more complex shapes than what can be realized using a single stamping operation. For example, the parts are automatically transferred from one operation to another by using for example a transfer press. For example, the parts stay in the same tool, which is a multipurpose tool that can perform the different operations, such as a first stamping and a subsequent in-tool trimming operation.

[0027]

[0030] A partial hardening hot stamping process is a hot stamping process in which the heat profile to which the blank is submitted is purposely tailored to be different in different areas of the blank, in order to obtain different material properties in these different areas at the end of the hot stamping process. For example, this allows to produce hot stamped parts using a single metallic blank made of a single material which will have different levels of hardness and elongation in different areas of the final part. For example, this allows to produce parts having soft zones and hard zones, said soft zones being able to deform under an impact load in order to absorb energy, whereas said hard zones will resist intrusion by resisting deformation. There are several different technologies to implement partial hardening. For example, the material can be heated at different temperatures in different areas of the blank, the higher temperature areas will be fully austenitic at the exit of the austenitizing furnace resulting in a very hard microstructure after hot stamping, whereas the lower temperature areas will have an intercritical ferrite I austenite microstructure at the exit of the austenitizing furnace resulting in a lower hardness microstructure after hot stamping. For example, the material can be quenched at different quenching speeds in different areas of the blank during the hot stamping step itself, the areas quenched at a higher quenching speed will have a higher hardness than those quenched at a lower speed.

[0028]

[0031] Figure 1 depicts the structure of a pickup truck frame 1 . The front end of said frame 1 houses a cab 2. In the case of figure 1 , a two row cab, also known as a crew cab, is depicted. Pickup trucks can also have a single row of passenger seats. All cab configurations are covered by the present invention.

[0029]

[0032] The passenger cab 2 is delimited on its sides by two opposing cab side structures 3. Said cab side structures 3 are delimited on their front and rear ends respectively by an A-pillar 4 and a C-pillar 5. Said C-pillar 5 extends in a substantially vertical direction between the rear end of a side sill 6, located at the very bottom of the cab side structure 3, and a roof rail 7, located at the top of said cab side structure 3.

[0030]

[0033] Referring to figure 1 , a cargo box 8 is located at the rear of the pickup frame 1 . Said cargo box comprises a base panel 12, on which cargo can be loaded. Said base panel 12 is attached on its sides to two longitudinal rails 13 and at the back of the cargo box to a cargo box rear cross beam 11 . The base panel 12 is surrounded by four upstanding walls to form a container. The walls include two side walls 9 on either side of the cargo box 8.

[0031]

[0034] In the current state of the art, the sub-parts making up the inner structure of said side wall 9 and said rear pillar 5 are all manufactured independently from one another and subsequently assembled together, typically by spot welding them to each other.

[0032]

[0035] Referring to figure 2a, the inventors have found that it is possible to design a rear side structure inner 10 for a pickup truck frame which combines the inner structures of said C-pillar 5 and said side wall 9 using only one large part per side which is made by stamping a single metallic blank.

[0033]

[0036] Said rear side structure inner 10 is manufactured by stamping a single inner blank 10b, and comprises:

[0034] -a C-pillar inner portion 101 extending substantially horizontally and attached at its bottom end to the side sill 6 and at its top end to the roof rail 7,

[0035] -a D-pillar inner portion 104 extending substantially horizontally and designed to be attached at its bottom end to the cargo box rear cross beam 11 ,

[0036] -said C-pillar inner portion 101 and D-pillar inner portion 104 being connected by a belt rail inner portion 102 extending substantially horizontally at a first elevation,

[0037] - said C-pillar inner portion 101 and D-pillar inner portion 104 being further connected by a wheelhouse inner portion 103 extending substantially horizontally at a second elevation, lower than said first elevation.

[0038]

[0037] In a particular embodiment, referring to figure 2b, the rear side structure inner 10 is manufactured by stamping a tailor welded blank 10b. For example, the above described different portions of the rear side structure inner 101 , 102, 103, 104, respectively correspond to a different individual sub-blank 101 b, 102b, 103b, 104b, . Advantageously this allows to allocate in each portion of the tailor welded blank the most optimal grade and thickness for in-use properties such as rigidity and crash resistance.

[0038] In a particular embodiment the irear side structure inner 10 is manufactured by stamping a tailor rolled blank. Advantageously, this allows to adjust the thickness of the blank used according to the strength and rigidity requirements of the different areas of the part.

[0039]

[0039] In a particular embodiment the rear side structure inner 10 is manufactured by hot stamping or complex hot stamping or using partial hardening hot stamping. Advantageously this allows to manufacture parts with very high strength and complex shapes. In a particular embodiment, hot stamping is carried out on a tailor welded blank 10b. In a particular embodiment, hot stamping is carried out on a tailor rolled blank.

[0040]

[0040] In a particular embodiment, the material making up the C-pillar inner portion 101 has a thickness comprised between 1.0mm and 1.2mm and is made of a grade having an ultimate tensile strength equal to or greater than 600MPa after stamping. For example, the inner blank 10b is a tailor welded blank comprising a C-pillar inner portion 101 b which has an ultimate tensile strength equal to or greater than 600MPa after stamping.

[0041]

[0041] In a particular embodiment, the material making up the D-pillar inner portion 104 has a thickness comprised between 1.0mm and 1.2mm and is made of a grade having an ultimate tensile strength equal to or greater than 340MPa after stamping, preferably 600MPa after stamping. For example, the inner blank 10b is a tailor welded blank comprising a D-pillar inner portion 104b which has an ultimate tensile strength equal to or greater than 340MPa after stamping, preferably 600MPa after stamping.

[0042]

[0042] In a particular embodiment, the material making up the wheelhouse inner portion 103 has a thickness comprised between 0.75mm and 1.0mm and is made of a grade having an ultimate tensile strength equal to or greater than 160MPa after stamping. For example, the inner blank 10b is a tailor welded blank comprising a wheelhouse inner portion 103b which has an ultimate tensile strength equal to or greater than 160MPa after stamping.

[0043]

[0043] In a particular embodiment, the material making up the belt rail inner portion 102 has a thickness comprised between 1.0mm and 1.2mm and is made of a grade having an ultimate tensile strength equal to or greater than 340MPa after stamping. For example, the inner blank 10b is a tailor welded blank comprising a belt rail inner portion 102b which has an ultimate tensile strength equal to or greater than 340MPa after stamping.

[0044]

[0044] The current invention further relates to a rear side structure assembly for a pickup truck frame 1 comprising a rear side structure inner 10 having the previously described characteristics, assembled to a rear side structure outer 20 comprising a C-pillar outer 201 , a D-pillar outer 204 and a belt rail outer 202, as depicted on figure 3. Once assembled said inner and outer side structures 10, 20 form together a box between the C-pillar inner portion and the C-pillar outer 101 , 201 , between the D-pillar inner portion and the D-pillar outer 104, 204 and in between the belt rail inner portion and the belt rail outer 102, 202.

[0045]

[0045] The term “forming a box” designates a geometric configuration wherein the contours of the corresponding portions of said inner and outer side structures 10, 20 form a closed cross section encompassing within it a hollow space. This type of configuration confers rigidity and resistance against shocks to the assembled rear side structure.

[0046]

[0046] In a particular embodiment, the inner and outer side structures 10, 20 are assembled together by welding them together along flanges running along the sides of at least one of the inner or outer side structure, for example by spot welding or laser welding. In a particular embodiment, the inner and outer side structures are assembled together mechanically, for example by bolting them together or by clinching. In a particular embodiment, the inner and outer side structures are assembled together by a combination of said assembly methods.

[0047]

[0047] The current invention further relates to a pickup truck having a passenger cab 2 and a cargo box 8, wherein said pickup truck comprises a rear side structure assembly as described previously.

Claims

CLAIMS1 ) Rear side structure inner (10) for a pickup truck frame (1 ) manufactured by stamping an inner blank (10b), comprising:-a C-pillar inner portion (101 ) extending substantially horizontally and attached at its bottom end to a side sill (6) and at its top end to a roof rail (7),-a D-pillar inner portion (104) extending substantially horizontally and designed to be attached at its bottom end to a cargo box rear cross beam (11 ),-said C-pillar inner portion (101 ) and D-pillar inner portion (104) being connected by a belt rail inner portion (102) extending substantially horizontally at a first elevation,- said C-pillar inner portion (101 ) and D-pillar inner portion (104) being further connected by a wheelhouse inner portion (103) extending substantially horizontally at a second elevation, lower than said first elevation.2) Rear side structure inner (10) according to claim 1 manufactured by stamping a tailor welded blank.3) Rear side structure inner (10) according to claim 1 manufactured by stamping a tailor rolled blank.4) Rear side structure inner (10) according to any one of claims 1 to 3 manufactured by hot stamping.5) Rear side structure inner (10) according to any one of claims 1 to 4, wherein the C-pillar inner portion (101 ) is generally U-shaped with flanges extending along its sides.6) Rear side structure inner (10) according to any one of claims 1 to 5, wherein the belt rail inner portion (102) is generally U-shaped with flanges extending along its sides.7) Rear side structure assembly for a pickup truck frame (1 ) comprising a rear side structure inner (10) according to any one of claims 1 to 6, assembled to a rear side structure outer (20) comprising a C-pillar outer (201 ), a D-pillar outer (204) and a belt rail outer (202), wherein once assembled said inner and outer side structures (10, 20) form together a box between the C-pillar inner portion and the C-pillar outer (101 , 201 ), between the D-pillar inner portion and the D-pillar outer (104, 204) and in between the belt rail inner portion and the belt rail outer (102, 202).8) Rear side structure assembly according to claim 7, wherein said rear side inner and outer structures (10, 20) are assembled together by welding them together along flanges running along the sides of at least one of the inner or outer side structure (10, 20).9) Pickup truck having a passenger cab (2) and a cargo box (8), wherein said pickup truck comprises a rear side structure assembly according to claim 7 or 8.

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