Internal reinforcement element for a plastic tank for motor vehicles

Abstract

The internal reinforcement element (2) of this plastic tank for motor vehicles is integrally realized, - a central part (4) having an arcuate cross-section, defining the main axis of the reinforcement element (2) and having a first area, the central part (4) including a rib network called a radial rib network (8) extending in a radial direction with respect to the main axis; - two axial ends (14) located on both sides of the central part (4) when viewed along the main axis, each axial end (14) having a curved oval end surface (16) which is included in the cross-section of the central part (4) and has a second area smaller than the first area; and includes.

Description

Technical Field

[0001] The present invention relates to an internal reinforcement element for a plastic tank for an automobile. The present invention also relates to a plastic tank for an automobile including the internal reinforcement element, and a method for manufacturing the plastic tank for an automobile.

Background Art

[0002] Conventionally, a fuel tank of an automobile is designed to store a certain amount of fuel at a pressure substantially the same as the atmospheric pressure. With the advent of hybrid vehicles, also referred to as HEV (Hybrid Electric Vehicle), MHEV (Mild-Hybrid Electric Vehicle), or PHEV (Plug-in Hybrid Electric Vehicle), in other words, automobiles that include an internal combustion engine and one or more electric motors and can run for several months without using the internal combustion engine, it is preferable to maintain the pressure inside the tank in order to reduce the passage of gasoline vapor through an activated carbon filter, also referred to as a canister. This is achieved by isolating the canister and the tank using a valve such as a Fuel Tank Isolation Valve (FTIV).

[0003] The size of this type of plastic fuel tank varies throughout its service life. This is because since this plastic fuel tank is obtained by extrusion blow molding of a parison, first immediately after demolding when the material shrinks due to cooling, and in addition during the service life, due to thermal expansion during the service life, temperature changes caused by daily cycles, or overpressure or underpressure of the contents due to aging deterioration.

[0004] Automotive plastic fuel tanks, and more specifically plastic fuel tanks for hybrid vehicles, typically include strut-shaped internal reinforcement elements that connect two opposing inner surfaces of the tank. This type of strut is required to withstand various tests, such as long-term aging tests or "handling drop" tests from a height of 1 meter, without compromising the characteristics of the fuel tank. For example, International Publication No. WO2012 / 139962 discloses hourglass-shaped circular struts that are highly resistant to axial stresses caused by tensile / compressive phenomena, as well as aging tests and durability tests. However, this type of strut is relatively weak against stresses caused by bending and / or torsional phenomena.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The main object of the present invention is to compensate for these drawbacks of the prior art. More specifically, the object of the present invention is to provide an internal reinforcement element for an automotive plastic tank that can withstand not only axial stresses caused by tensile / compressive phenomena but also bending and torsional phenomena, and which can be easily obtained by injection molding.

Means for Solving the Problems

[0007] For this purpose, the present invention provides an internal reinforcement element for an automotive plastic tank, - a central portion having an arcuate cross-section, defining a major axis of the reinforcement element and having a first area, the major axis passing through the center of rotation of the arcuate portion perpendicular to the arcuate portion, and the central portion extending radially with respect to the major axis, the central portion including a rib network referred to as a radial rib network; - Two axial ends located on both sides of the central part when viewed along the spindle axis, each axial end having a curved oval end surface that is included in the cross-section of the central part and has a second area smaller than the first area This relates to an integrally realized internal reinforcement element including

[0008] The curved shape of the central part and its rib structure can effectively disperse the stress transmitted to this element in various directions, as shown by the analysis results implemented by the inventors using the finished product of the internal reinforcement element. It is understood that this type of internal reinforcement element is more resistant to bending and torsion phenomena than the prior art struts characterized by a structure describable as unidirectional.

[0009] Furthermore, the curved shape of the internal reinforcement element makes it easier to release the internal reinforcement element from the stress caused by its position within the tank. For example, the concave part of the internal reinforcement element can surround the accessories provided within the tank, and as a result, not all of the volume of this concave part is wasted. Such an arrangement cannot be achieved with the prior art struts.

[0010] Furthermore, according to the simulation test, when the end surface is not oval, that is, when this surface has sharp corners, it has been revealed that stress concentrates at the positions of these corners, thereby creating vulnerable points in the internal reinforcement element. The inventors have confirmed that by changing these sharp corners into rounded edges to make them oval, the stress is evenly dispersed throughout the internal reinforcement element without concentrating on these rounded edges. Similar results have also been observed in this type of simulation test by reducing the cross-section as it transitions from the central part to the axial end.

[0011] Advantageously, the internal reinforcement element is entirely realized in high-density polyethylene (HDPE) or high-density polyethylene reinforced with glass fibers.

[0012] In this way, the internal reinforcing element is realized using a material that is easy and inexpensive to inject and weld. To further improve the physical properties of the internal reinforcing element, for example, high-density polyethylene can be reinforced with up to 10% by weight of glass fibers.

[0013] Advantageously, each of the end surfaces includes an axial protrusion network.

[0014] The axial protrusions facilitate welding of the internal reinforcing element to the tank wall. In particular, this protrusion enables welding without preheating.

[0015] Preferably, each of the end surfaces includes an axial rib perforated assembly surrounding the axial protrusion network.

[0016] The axial ribs, which are also for welding to the tank wall, improve the holding force of the welding of the internal reinforcing element to the tank wall by enabling air evacuation during welding. In other words, the axial ribs prevent weakening of the joint between the internal reinforcing element and the tank due to air accumulation between the axial end surface and the tank wall.

[0017] Advantageously, the radial rib network includes linear ribs extending perpendicular or parallel to the main axis and defining a substantially cuboid-shaped depression between each rib, and cylindrical ribs defining a substantially cylindrical depression between each rib.

[0018] In this way, the radial rib network forms a network of blind holes in the central part of the internal strengthening element, thereby imparting a waffle-like shape to the central part. This type of network improves the rigidity of the internal reinforcing element. Furthermore, the radial rib network imparts a soundproofing effect to the internal reinforcing element by a mechanism similar to the acoustic properties of an egg carton.

[0019] Advantageously, the radial ribs form a left-right asymmetric network.

[0020] That is, by forcibly determining the position and direction of the internal reinforcing element in the tank and avoiding assembly errors of the internal reinforcing element into the tank, an anti-misoperation function, also referred to in Japanese as "poka (careless mistake) yoke (prevention)", which can reduce the rejection rate in the manufacture of plastic tanks for automobiles, is imparted to the radial rib network.

[0021] Advantageously, the internal reinforcing element includes gripping means located on the side wall of the central part.

[0022] Thus, the internal reinforcing element is provided with means that can be adapted to various molding techniques, whereby the present invention can be easily implemented.

[0023] Advantageously, the end surface has a shape in which the four corners are changed to rounded edges, corresponding to a similar shape of an arc portion with a similarity ratio k of 1 or less. In other words, the end surface extends along an angular sector and a radius corresponding to the angular sector and the radius of the central arc portion multiplied by a similarity ratio k of less than 1, and has an arc shape in which the four corners are changed to rounded edges.

[0024] In addition to being easily realized, the end surface has a shape close to the cross-section of the central part in this way. Thus, the geometric transition part between the central part and each end does not have a shape that can concentrate stress and does not weaken the internal reinforcing element.

[0025] According to a specific embodiment of the present invention, the arc shape of the cross-section of the central part has an infinite radius, and the curved oval shape of the end surface of each axial end also has an infinite radius. In other words, the reinforcing element has a linear shape rather than a curved shape.

[0026] The linear-shaped reinforcing element does not have as many advantages as the curved-shaped reinforcing element, but the linear-shaped reinforcing element has a cross-section that decreases as it transitions from the central part to each axial end and the aforementioned advantages resulting from the oval shape.

[0027] The present invention also envisages a plastic tank for automobiles including an internal reinforcing element as defined above.

[0028] The present invention also contemplates a method for manufacturing a plastic tank for an automobile, in which internal reinforcing elements as defined above are welded to two opposing inner walls of the tank.

[0029] The present invention will be more readily understood by reading the following description given merely by way of example with reference to the accompanying drawings below.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0031] Shown in FIG. 1 is an internal reinforcing element 2 of a plastic tank for an automobile according to an embodiment of the present invention. The internal reinforcing element 2 is integrally realized with a material suitable for welding to the wall of the plastic tank throughout. Here, the reinforcing element 2 is realized throughout with high-density polyethylene (HDPE) or high-density polyethylene reinforced with glass fibers.

[0032] The reinforcing element 2 includes a central portion 4 having an arcuate cross-section with respect to a main axis 6 that defines the axial direction of the reinforcing element 2. The main axis 6 is defined as an axis that passes through the center of rotation of the arcuate portion perpendicular to the arcuate portion. This is the axis of rotation of the arcuate portion. That is, the main axis 6 extends outside the arcuate portion and the internal reinforcing element 2. Since the main characteristic of the main axis 6 according to the present invention is its direction rather than its position, for the sake of clarity of the drawings, the main axis 6 is illustrated with an axis extending into or on the surface of the internal reinforcing element 2. In other words, the axis denoted by the reference numeral "6" on each drawing is an axis parallel to the main axis and indicates the axial direction. As is well shown in the front view of the internal reinforcing element 2 which is the subject of FIG. 2, the central portion 4 includes a rib network called a radial rib network 8 that extends radially with respect to the main axis 6.

[0033] The radial rib network 8 includes linear ribs 8a that extend perpendicular or parallel to the main axis 6 and define a substantially cuboid-shaped indentation or blind hole between each rib. The radial rib network 8 also includes cylindrical ribs 8b that define a substantially cylindrical indentation or blind hole between each rib. The linear ribs 8a contribute to its physical properties, especially by improving the durability of the internal reinforcing element 2 against bending and torsion. The radial ribs 8b also contribute to strengthening the physical properties of the internal reinforcing element 2, but their role is not limited to this. The radial ribs 8b form a left-right asymmetric network capable of realizing an anti-misoperation function. In other words, depending on the position of the radial ribs 8b, the operator can install the internal reinforcing element 2 in the correct position and in the correct direction within the tank, preventing installation in the reverse direction that may impair its optimal reinforcing function. Here, in FIG. 2, it can be seen that the central portion 4 of the internal reinforcing element 2 includes a radial rib 8b located on the circumcircle of the central portion 4 and another radial rib 8b located away from the circumcircle. With the latter radial rib, the operator can orient the internal reinforcing element 2 in the correct direction within the tank.

[0034] Figure 3 shows a cross-sectional view of the internal reinforcement element 2, in which the arc shape of the central portion 4 can be seen. For this purpose, in order to obtain a solid surface such as the dashed line 9 shown in Figure 3, the blind holes defined by the radial rib network 8 are virtually filled. The cross-section of the central portion 4 assumed on a plane perpendicular to the main axis 6 has a first area a 1 and has.

[0035] Returning to Figure 2, the internal reinforcement element 2 includes gripping means 10 located on the side wall 12 of the central portion 4. In this embodiment of the present invention, the central portion 4 of the reinforcement element 2 includes two opposing side walls 12 each including the gripping means 10. Each of the gripping means 10 has a straight handle shape connected at two points on the corresponding side wall 12. The shape of the gripping means 10 can be likened to the shape of the handle of a carry-on bag. The gripping means 10 facilitates the insertion of the internal reinforcement element 2 during the manufacture of a plastic tank, especially when this is achieved by blow molding using the technique of inserting an internal reinforcement element into a parison.

[0036] The internal reinforcement element 2 includes two axial end portions 14 located on both sides of the central portion 4 as viewed along the main axis 6. As well shown in Figure 4 which is a top view of the internal reinforcement element 2, each axial end portion 14 has a curved oval end surface 16 that is included in the cross-section of the central portion 4 and has a second area a 1 smaller than 2 the first area a. Here, the end surface 16 has a shape in which the four corners are changed to rounded edges 18, corresponding to a similar shape of the arc portion of the central portion with a similarity ratio k of 1 or less. Preferably, the similarity ratio k is selected from among greater than 0.5, or greater than 0.8, and further greater than 0.9. According to the same definition, the end surface 16 extends along the angular sector and radius corresponding to the angular sector and radius of the central portion arc portion multiplied by a similarity ratio k of less than 1, and has an arc shape in which the four corners are changed to rounded edges 18. The end surface 16 is for being welded to two opposing walls of the plastic tank.

[0037] Each end surface 16 includes an axial protrusion network 20 extending parallel to the spindle 6 over a length of 1 to 2 millimeters. Here, the axial protrusions 20 are arranged along a radial row and occupy most of the area of the end surface 16. Each end surface 16 further includes a perforated assembly of axial ribs 22 surrounding the axial protrusion network 20. This means that the axial ribs 22 define an outer edge encompassing all the axial protrusions 20. The axial ribs 22 are perforated to allow air evacuation when welding the end surface 16 to the wall of the tank, in other words, there are gaps between the ribs.

[0038] The reinforcing element 2 is manufactured by an injection molding type method. Due to its geometry, especially the geometry of the radial rib network 8, the molding can be easily realized in one operation.

[0039] Shown in FIG. 5 is a plastic tank 24 according to the present invention. The tank 24 includes an internal reinforcing element 2, which is welded to two opposing walls 26 of the tank 24. The welding of the internal reinforcing element 2 to the wall 26 of the tank can be realized using any suitable technique during or after the molding of the tank 24. The gripping means 10 may be fixed by a holding member (not shown) to facilitate the welding of the reinforcing element 2 to the wall 26 of the tank.

[0040] The present invention is not limited to each of the introduced embodiments, and other embodiments will also be clearly envisioned by those skilled in the art.

Description of Reference Numerals

[0041] 2 Internal reinforcing element 4 Central part 6 Spindle 8 Radial rib network 8a Straight rib 8b Cylindrical rib 9 Dashed line 10 Gripping means 12 Side wall 14 Axial end 16 End surface 18 Rounded edge 20 Axial Protrusion Network 22 Axial Rib 24 Tank 26 Tank Wall

Claims

1. An internal reinforcement element (2) for a plastic tank for an automobile, - having a cross-section in the shape of an arc, defining the main axis (6) of said reinforcing element (2), and having a first area (a １ ) of a central portion (4), wherein said main axis (6) passes through the center of rotation of said arc portion perpendicular to said arc portion, and said central portion (4) extends radially with respect to said main axis, and a central portion (4) including a rib network called a radial rib network (8). - Two axial ends (14) located on both sides of the central part (4) when viewed along the main shaft (6), each of the axial ends (14) being included in the cross section of the central part (4) and having a second area (a １ ) smaller than the first area (a ２ ), and having a curved oval end surface (16), the axial end (14) An integrally realized internal reinforcement element (2) including

2. The reinforcement element (2) according to claim 1, which is entirely realized in high-density polyethylene (HDPE) or high-density polyethylene reinforced with glass fibers.

3. The reinforcement element (2) according to claim 1 or 2, wherein each of the end surfaces (16) includes an axial protrusion network (20).

4. The reinforcement element (2) according to claim 3, wherein each of the end surfaces (16) includes an axial rib perforation assembly (22) surrounding the axial protrusion network (20).

5. The reinforcement element (2) according to any one of claims 1 to 4, wherein the radial rib network (8) includes linear ribs (8a) extending perpendicular or parallel to the main axis (6) and defining a substantially cuboid recess between each rib, and cylindrical ribs (8b) defining a substantially cylindrical recess between each rib.

6. The reinforcement element (2) according to any one of claims 1 to 5, wherein the radial ribs (8) form a left-right asymmetric network.

7. The reinforcement element (2) according to any one of claims 1 to 6, including gripping means (10) located on the side wall (12) of the central portion (4).

8. The reinforcement element (2) according to any one of claims 1 to 7, wherein the end surface (16) has a shape in which the four corners are changed to rounded edges and corresponds to a similar shape of an arc portion with a similarity ratio k of 1 or less.

9. A plastic tank (24) for an automobile including the reinforcement element (2) according to any one of claims 1 to 8.

10. A method for manufacturing a plastic tank (24) for an automobile, wherein the reinforcement element (2) according to any one of claims 1 to 8 is welded to two opposing inner walls (26) of the tank (24).

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