AU2023202667A1

AU2023202667A1 - Vehicle rim with one of at least one subpreform flange area; and method of making a rim body

Info

Publication number: AU2023202667A1
Application number: AU2023202667A
Authority: AU
Inventors: Olaf RÜGER; Christoph SCHRANZ
Original assignee: Munich Composites GmbH
Current assignee: Munich Composites GmbH
Priority date: 2022-05-02
Filing date: 2023-05-01
Publication date: 2023-11-16
Also published as: EP4272937A1; TW202344415A; DE102022110699A1; JP2023165400A; KR20230154762A; CN116985563A

Abstract

The invention relates to a vehicle rim (1) having a rim body (2) made of fiber composite material, the rim body (2) in turn having a first sub-preform (4) forming a first axial end (3a) and a second sub-preform (6) accommodated in a connecting cavity (5) of the first sub-preform (4) and extending from the first sub-preform (4) to a second axial end (3b) opposite the first axial end (3a), second axial end (3b) opposite the first axial end (3a), wherein furthermore a radially inwardly projecting flange region (7) formed axially between the axial ends (3a, 3b) is at least partially formed from a third sub-preform (8) connected to the first sub-preform (4) and/or the second sub-preform (6). The invention also relates to a method for manufacturing a vehicle rim (1). (Fig. 1) 1/4 3a 24 18,19 124 3b 22 5 4 8 9 13 6 2 21 23 2 0 12 101 7 Fig. 1

Description

1/4

3a 24 18,19 124 3b 22 5 4 8 9 13 6 2 21 23

20

12 101

7

Fig. 1

Vehicle rim having a flange portion constructed from at least one sub-preform; and method for manufacturing a rim body

FIELD OF THE INVENTION

[0001] The invention relates to a vehicle rim with a typically hollow, preferably (rotationally) symmetrical rim body made of fiber composite material.

BACKGROUND OF THE INVENTION

[0002] Any discussion of the background art throughout the specification should in no way be considered as an admission that such art is widely known or forms part of common general knowledge in the field.

[0003] Vehicle rims with a rim body made of fiber composite material are known from the prior art. These rim bodies typically have woven fabrics, scrims or braids comprising carbon fibers, glass fibers or aramid fibers, pre-impregnated or later injected with resin. After curing, a vehicle rim comprising said rim body is provided.

[0004] It is also known that the rim body made of fiber composite material can be connected to a further component which is provided for attachment to the wheel hub of a vehicle, such as a car, a truck or another commercial vehicle, but also of, for example, motor-driven two-wheeled vehicles. Often this component is formed as a star and is usually made of metal or a metal alloy, such as an aluminum alloy.

[0005] However, to date it has been very time-consuming and cost-intensive to manufacture the aforementioned (CFRP) rim bodies. Such rim bodies are also not yet as resilient as desired. In particular, thermal loads, pressures and centripetal forces must still be better endured. Such a rim body should also be extremely stiff and light.

SUMMARY OF THE INVENTION

[0006] It is an object of the invention, in its preferred form to provide for an improved vechicle rim.

[0007] In accordance with a first aspect of the present invention, there is provided a vehicle rim having a rim body made of fiber composite material, the rim body in turn having a first sub-preform forming a first axial end and a second sub-preform received in a connecting cavity of the first sub-preform and extending from the first sub-preform to a second axial end opposite the first axial end, second axial end opposite the first axial end, wherein furthermore a radially inwardly projecting flange region formed axially between the axial ends is formed at least partially from a third sub-preform connected to the first sub-preform and/or the second sub-preform.

[0008] In some embodiments, there is provided a vehicle rim with a typically hollow, preferably (rotationally) symmetrical rim body made of fiber composite material, wherein the rim body in turn comprises a first sub-preform forming a first axial end and a second sub-preform received in a connecting cavity of the first sub-preform, a second sub-preform extending from the first sub-preform to a second axial end opposite the first axial end, wherein furthermore a radially inwardly projecting flange region formed axially between the axial ends is at least partially formed from a third sub-preform connected to the first sub-preform and/or the second sub-preform.

[0009] Due to the possibility of using several different sub-preforms, the work steps can be carried out in parallel, thus saving time. The further (third) sub-preform forming the flange area makes a critical connection area for a rim star as stiff and loadable as possible.

[0010] The invention has also set itself the task of preferably providing a particularly fast and reliable, i.e. failure-proof, process for producing a rim body from fiber composite material for a vehicle rim.

[0011] In accordance with another aspect of the present invention, there is provided a method of manufacturing a rim body of fiber composite material for a vehicle rim, wherein a first sub-preform having a reinforcing fiber is arranged to form a first axial end of the rim body, and a second sub-preform is inserted into a connecting cavity of the first sub-preform, wherein the second sub-preform extends axially away from the first sub-preform to a second axial end of the rim body, and wherein a third sub-preform is attached to the first sub-preform and/or the second sub-preform, so that the latter co-forms a radially inwardly projecting flange region prepared for connection of a rim star.

[0012] Such a method of manufacturing a rim body of fiber composite material for a vehicle rim is preferably characterized in that a first sub-preform comprising a reinforcing fiber (preferably carbon fiber, glass fiber and/or aramid fiber comprising NCF (non-crimp fabric)) is arranged to form a first axial end of the rim body, and a second sub-preform (comprising a same or similar reinforcing fiber as the first sub preform) is inserted into a connecting cavity of the first sub-preform, wherein the second sub-preform extends axially from the first sub-preform to a second axial end of the rim body, and wherein a third sub preform (comprising a same or similar reinforcing fiber as the first sub-preform) is attached to at least one of the first sub-preform and the second sub-preform so as to co-form a radially inwardly projecting flange portion prepared for connection to a rim star.

[0013] Advantageous further embodiments of the vehicle rim are set out below. These advantageous further embodiments are explained in more detail below.

[0014] Accordingly, it is also advantageous if the flange region is co-formed from a further fourth sub preform. This further increases the strength of the flange region.

[0015] It is also advantageous if the third sub-preform and the fourth sub-preform each have a radially inwardly projecting collar that directly forms the flange area. This means that the third and fourth sub preforms can be formed as simply as possible, thus keeping the assembly work to a minimum.

[0016] For ease of manufacture, it is also beneficial if the third sub-preform and/or the fourth sub preform have a (substantially axially projecting) ring portion, the respective ring portion being (preferably directly) connected to the first sub-preform and/or the second sub-preform.

[0017] If the ring portions of the third sub-preform and the fourth sub-preform extend to opposite axial directions outward from flange region/from each other, the strength of the flange region is further increased.

[0018] Furthermore, it is advantageous if the third sub-preform is also arranged in the connecting cavity of the first sub-preform. This also cleverly increases the strength of the rim body without having to use additional fasteners.

[0019] If the first sub-preform has a radially inwardly projecting collar that also forms the flange region, the strength of the flange region is also increased.

[0020] Furthermore, in order to implement a hybrid rim that is as durable as possible, it is advantageous if a rim star made of metal, preferably a light metal alloy such as an aluminum alloy, is attached (directly) to the flange area by means of a screw connection.

[0021] For strength-optimized attachment of the rim star, it is also advantageous if the flange area is penetrated by screw-receiving holes at a point where the collars of the third sub-preform and the fourth sub preform (and preferably also the collar of the first sub-preform) overlap radially.

[0022] Further, it is advantageous if a filler core (preferably in the form of a fiber bundle) is inserted in a ring space between both the second sub-preform as well as the third sub-preform and/or the fourth sub preform.

[0023] For adequate stability, it is also advantageous if a fifth sub-preform, which directly forms this second axial end, is connected to the second sub-preform. The second sub-preform is preferably inserted/accommodated in a connecting cavity of the fifth sub-preform and connected to it there.

[0024] Thus, it is also advantageous if the second sub-preform is mounted/attached to the first sub preform and the fifth sub-preform, in particular as a single piece/integrally, in the two connecting cavities. Good long-term durability is then ensured.

[0025] If all sub-preforms are interspersed by the same resin/resin blend, a cohesive, rigid but particularly lightweight component becomes possible.

[0026] In order to keep the costs low while still maintaining a high load-bearing capacity of the end product, it has proved useful if the first sub-preform and/or the second sub-preform and/or the third sub preform and/or the fourth sub-preform and/or the fifth sub-preform have an NCF or are completely built up from it.

[0027] An NCF is understood to be a "non-crimp fabric". This is a fabric consisting of one or more layers of parallel stretched threads. The threads are usually fixed at the crossing points. The fixation takes place either by fabric closure or mechanically by friction and/or form closure.

[0028] The following types of filament couplings are available:

[0029] Monoaxial or unidirectional yam clutches, which are formed by fixing one set of parallel yams;

[0030] Biaxial yam clutches, in which two sets of parallel yams are fixed in the direction of two axes;

[0031] Multiaxial yam clutches, in which several pairs of parallel yams are fixed in the direction of different axes.

[0032] The thread layers in multilayer scrims can all have different orientations and can also consist of different thread densities and different thread finenesses. Compared to woven fabrics, scrims as reinforcing structures are known to have better mechanical properties in fiber-plastic composites, this being the basic technical field in which the invention is arranged, since the threads are in stretched form and thus there is no additional structural stretch and the orientation of the threads can be defined specifically for the application in question.

[0033] In order to be able to manufacture particularly heavy-duty vehicle rims with a corresponding rim body, it has proved useful if the NCF is a monoaxial/unidirectional, or biaxial (e.g. containing +/- 45 fibers) or multiaxial scrim, preferably made of carbon fibers, glass fibers or aramid fibers.

[0034] Particularly high forces at low weight can be absorbed by the rim body if the first sub-preform and/or the second sub-preform and/or the third sub-preform and/or the fourth sub-preform and/or the fifth sub-preform has/have several, e.g. 3, 4, 5, 6, 7, 8 or more layers of NCF.

[0035] It is convenient if the filler core used is a roving bundle. "Rovings" are understood to be fiber filaments, in particular man-made fiber filaments. A "roving" is understood here to be a bundle, strand or multifilament yarn of filaments/continuous fibers arranged in parallel. The cross-section of a "roving" is often elliptical or rectangular. Such rovings, which have a slight protective twist, for example five or ten twists per meter, are intended to be included herein, making the cross-section more rounded. In particular, such filaments made of glass, aramid or carbon thereby form a roving.

[0036] The stiffness / weight ratio is particularly advantageous if the first sub-preform and/or the fifth sub-preform is wound/built up in at least 4, 5 or 6 layers and/or the second sub-preform is wound/built up in at least 5, 6 or 7 layers.

[0037] If the sub-preforms directly abutting/fastened/connected to each other are completely or partially fastened to each other in a non-slip manner by means of a preferably thermally activated binder, production is significantly simplified. Alternatively or in addition to the connection by means of activation of the (preferably thermal) binder, it is also advantageous if the sub-preforms are connected to each other by inserting a (3D) seam.

[0038] With regard to the manufacturing process of the rim body, it is also advantageous if the first sub preform, the second sub-preform, the third sub-preform, the fourth sub-preform and the fifth sub-preform are infiltrated with resin simultaneously and these five components are cured together. It is convenient to charge the five sub-preforms with resin by means of RTM injection.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which both the device, i.e. the vehicle rim, and the manufacturing process is described:

[0040] Fig. illustrates a schematic longitudinal sectional view of a rim body of a vehicle rim according to a preferred embodiment, with which various sub-preforms serving to form the rim body,

[0041] Fig. 2 illustrates a detailed view of the rim body of Fig. 1 shown in longitudinal section in the region of a flange area prepared for connection of a rim star,

[0042] Fig. 3 illustrates a further detailed view of the rim body shown in longitudinal section in Fig. 1, where the course of the fiber layers of the various sub-preforms in the region of the flange area can now be seen,

[0043] Fig. 4 illustrates a front view of the entire rim body, with the extension of the flange area clearly visible,

[0044] Fig. 5 illustrates a front view of a vehicle rim comprising the rim body of figures 1 to 4 and a rim star attached to the flange portion of the rim body,

[0045] Fig. 6 illustrates a rear view of the vehicle rim of Fig. 5 to illustrate a bolted connection securing the rim star to the flange area, and

[0046] Fig. 7 illustrates a flowchart illustrating a manufacturing process for the vehicle rim of Figures I to 4.

[0047] The figures are of a schematic nature only and serve only to aid understanding of the invention. The same elements are provided with the same reference numbers.

DETAILED DESCRIPTION

[0048] Figures 5 and 6 show a vehicle rim 1 according to the invention. It has a rim body 2 shown in more detail in Figures 1 to 4 with regard to its structure. The rim body 2 is made of fiber composite material cured in the final state, having reinforcing fibers in the form of reinforcing threads, for example carbon fiber, glass fiber and/or aramid fiber threads, embedded in a resin matrix. Mixtures of the different filaments are also possible. The rim body 2 is composed of a plurality of individual parts, comprising a first sub preform 4, a second sub-preform 6, a third sub-preform 8, a fourth sub-preform 9, and a fifth sub-preform 20.

[0049] The first sub-preform 4 and the fifth sub-preform 20 are turned upside down/inside out/over in such a way that a (front) first connecting cavity 5 (of the first sub-preform 4) and a (rear) second connecting cavity 21 (of the fifth sub-preform 20) are formed in its interior, respectively. These two connecting cavities and 21 are cavities formed by the material of the corresponding first sub-preform 4 and fifth sub-preform , respectively. Ends of the second sub-preform 6 are arranged/inserted in the two connecting cavities 5 and 21, these ends being provided with the reference signs 22 and 23.

[0050] There is resin/resin blend between the first end 22 of the second sub-preform 6 and the material of the first sub-preform 4, respectively, the second end 23 of the second sub-preform 6 and the material of the third sub-preform 8. This resin is the same resin that impregnates all five sub-preforms 4, 6, 8, 9 and 20 and bonds them in the cured state.

[0051] A binder powder is used to produce sub-preforms 4, 6, 8, 9 and 20 and to pre-attach sub-preforms 4, 6, 8, 9 and 20 to each other. The resin is not added until the entire already assembled mold of the rim body 2 is injected during RTM injection. The binder powder then dissolves in the resin mixture during injection.

[0052] The first end 22 and/or the second end 23 may be bonded to the respective first sub-preform 4 or fifth sub-preform 20 with a (3D) seam in addition or as an alternative to the resin contained in the connecting cavities 5 or 21.

[0053] A tire to be mounted later on the rim body 2 is supported in the usual manner by rim flanges 24 of the rim body 2. A first axial end 3a of the rim body 2 is directly formed by the first sub-preform 4. In the region of this first axial end 3a, a rim flange 24 of the rim body 2 is directly formed by the first sub-preform 4. A second axial end 3b of the rim body 2 is directly formed by the fifth sub-preform 20. In the region of this second axial end 3b, a further rim flange 24 of the rim body 2 is directly formed by the fifth sub preform 20. To reinforce the respective rim flange 24, roving bundles are preferably incorporated in the first sub-preform 4 or in the fifth sub-preform 20 in the usual manner.

[0054] In addition, it should be noted that several plies of a (single) NCF material 25 are used. Preferably, a biaxial scrim with +/- 45 threads is used.

[0055] However, ends/edges of the NCF material 25 are not folded over in a particular embodiment, but simply lie on top of each other at the same position or with an offset. Connection of the first sub-preform 4 and the fifth sub-preform 20 with the second sub-preform 6 is preferably done simultaneously with the folding over.

[0056] Furthermore, according to the invention, two further sub-preforms, namely a third sub-preform 8 and a fourth sub-preform 9, are provided that serve to directly form a flange region 7 of the rim body 2 projecting radially inwards from the second sub-preform 6. Viewed more closely, the third sub-preform 8 and the fourth sub-preform 9 each have a collar 10, 11 projecting radially inwardly from the axially extending second sub-preform 6 and directly helping to form the flange region 7. The collars 10, 11 bear directly against one another and are bonded directly to one another in the finished state. The collars 10, 11 have the same inside diameters.

[0057] The third sub-preform 8 and the fourth sub-preform 9 each have an axially projecting ring portion 12, 13 (also referred to as an attachment portion) (from their respective collars 10, 11) that is directly connected to the second sub-preform 6. In particular, the ring sections 12, 13 of the third sub-preform 8 and the fourth sub-preform 9 extend in opposite axial directions away from the flange area 7.

[0058] Furthermore, it can be seen that the third sub-preform 8 with its ring section 12 is also inserted into the first connecting cavity 5 and fastened/anchored there. Thus, the third sub-preform 8 is radially covered from the inside by the first sub-preform 4 on the part of its ring section 12. In other words, the third sub-preform 8 is at least partially overlapped by the first sub-preform 4.

[0059] It should be noted that the first sub-preform 4 also overhangs/overlaps the collar 10 of the third sub-preform 8. The first sub-preform 4 thus has its own collar 14 that projects radially inwards beyond the second sub-preform 6. The collar 14 of the first sub-preform 4 also serves to help form the flange area 7. Together with the collars 10, 11 of the third sub-preform 8 and the fourth sub-preform 9, the collar 14 of the first sub-preform 4 forms the flange area 7. The collar 14 of the first sub-preform 4 extends radially inwards to such an extent that it has the same inside diameter as the collars 10, 11 of the third sub-preform 8 and the fourth sub-preform 9.

[0060] In other words, the third sub-preform 8 is therefore attached/bonded to both the first sub-preform 4 and the second sub-preform 6.

[0061] In contrast, the ring section 13 of the fourth sub-preform 9 is arranged (axially) outside the first connecting cavity 5, where it is bonded to the second sub-preform 6.

[0062] It can be seen in Figure 3 that the structure of the third sub-preform 8 and the fourth sub-preform 9 is largely similar/identical to that of the other sub-preforms 4, 6, 20. The third sub-preform 8 and the fourth sub-preform 9 also each have several layers of a (single) NCF material 25, the extension of which follows the L-shape of the third sub-preform 8 or the fourth sub-preform 9 in cross-section.

[0063] It can also be clearly seen in Figure 2 that a filler core 19, in this case in the form of a fiber/roving bundle, is inserted in a ring space 18 between the second sub-preform 6 on the one hand and the third sub preform 8 and the fourth sub-preform 9 on the other. The filler core 19 is located radially at the level of the transition between the respective (exclusively radially extending) collar 10, 11 of the third and fourth sub preforms 8, 9 and the adjoining, axially extending ring portion 12, 13.

[0064] Finally, Figures 4 to 6 illustrate the entire vehicle rim 1 (motor vehicle rim). A rim star 15 made of metal, in this case an aluminum alloy, is attached to the flange area 7 by means of a screw connection

16. For this purpose, as shown in Fig. 6, the rim star 15 is fastened to the flange area 7 at each radially outer end area of its spokes 27 with corresponding screw elements 26. For this purpose, the flange area 7 is provided with a screw-receiving hole 17 (as an axial through-hole) for each spoke 27, through which the screw element 26 projects.

[0065] Furthermore, the flange area 7 is penetrated by the bolt receiving holes 17 at the point where the collars 12, 13 of the third sub-preform 8 and the fourth sub-preform 9 and furthermore also the collar 14 of the first sub-preform 4 radially overlap.

[0066] In connection with Fig. 7, reference should also be made to a manufacturing process of the rim body 2 according to the invention.

[0067] In this process, the second sub-preform 6 is connected to the fifth sub-preform 20, wherein in particular the second sub-preform 6 is inserted into the second connecting cavity 21 of the fifth sub-preform (step a)).

[0068] The fourth sub-preform 9 is then joined to the second sub-preform 6 (step b)). In principle, steps a) and b) can also be carried out in reverse order or simultaneously/in parallel.

[0069] Following this, in an optional step c), the filler core 19 is applied to/fixed to the second sub preform 6, for example sewn or glued on.

[0070] The first sub-preform 4 is then arranged, with the second sub-preform 6 being fixed on the first sub-preform 4 (step d)). The second sub-preform 6 thereby extends axially away from the first sub-preform 4 towards the second axial end 3b of the rim body 2. Moreover, at the same time or subsequently thereto, the third sub-preform 8 is arranged and pre-fixed on the second sub-preform 6. Accordingly, the first sub preform 4 is then folded over so that the second sub-preform 6 as well as the third sub-preform 8 are inserted in the first connecting cavity 5 of the first sub-preform 4 (step e)). Steps d) and e) can in principle be carried out one after the other or simultaneously/in parallel.

[0071] Finally, when the sub-preforms 4, 6, 8, 9, 20 are fully fixed and draped, the third sub-preform 8 and the fourth sub-preform 9 are also arranged in such a way that they also form the radially inwardly projecting flange area 7 prepared for the connection of the rim star 15. Finally, the RTM injection is carried out and the rim body 2 is cured. In principle, further layers or coatings can be applied to the aforementioned sub-preforms 4, 6, 8, 9, 20. Specifically, it can be said that for optical reasons a carbon fabric can usually be applied as the outermost layer.

[0072] To produce the finished vehicle rim 1, the rim star 15/wheel star is then coupled to the rim body 2.

[0073] In the claims below and the description herein, any one of the terms comprising, comprised of or which comprises is an open term that means including at least the elements/features that follow, but not excluding others. Thus, the term comprising, when used in the claims, should not be interpreted as being limitative to the means or elements or steps listed thereafter. For example, the scope of the expression a device comprising A and B should not be limited to devices consisting only of elements A and B. Any one of the terms including or which includes or that includes as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.

[0074] Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as falling within the scope of the invention.

List of reference numbers

1 Vehicle rim 2 Rim body 3a First axial end of rim body 3b Second axial end of rim body 4 First sub-preform First connecting cavity 6 Second sub-preform 7 Flange area 8 Third sub-preform 9 Fourth sub-preform Collar of the third sub-preform 11 Collar of the fourth sub-preform 12 Ring section of the third sub-preform 13 Ring section of the fourth sub-preform 14 Collar of the first sub-preform Rim star 16 Bolt connection 17 Bolt receiving hole 18 Ring space 19 Filler core Fifth sub-preform 21 Second connecting cavity 22 First end of second sub-preform 23 Second end of second sub-preform 24 Rim flange NCF material 26 Screw element 27 Spoke

Claims

1. A vehicle rim having a rim body made of fiber composite material, the rim body in turn having a first sub-preform forming a first axial end and a second sub-preform received in a connecting cavity of the first sub-preform and extending from the first sub-preform to a second axial end opposite the first axial end, second axial end opposite the first axial end, wherein furthermore a radially inwardly projecting flange region formed axially between the axial ends is formed at least partially from a third sub-preform connected to the first sub-preform and/or the second sub-preform

. 2. A vehicle rim according to claim 1, characterized in that the flange region is formed from a further fourth sub-preform.

3. A vehicle rim according to claim 2, characterized in that the third sub-preform and the fourth sub preform each have a radially inwardly projecting collar directly forming the flange region as well.

4. A vehicle rim according to any one of claims 1 to 3, characterized in that the third sub-preform and/or the fourth sub-preform have/has a substantially axially projecting ring portion, which ring portion is connected to the first sub-preform and/or the second sub-preform .

5. A vehicle rim according to claim 4, characterized in that the ring portions of the third sub-preform and the fourth sub-preform extend to opposite axial directions away from the flange area .

6. A vehicle rim according to one of claims 1 to 5, characterized in that the third sub-preform is arranged in the connecting cavity of the first sub-preform as well.

7. A vehicle rim according to one of claims 1 to 6, characterized in that the first sub-preform has a radially inwardly projecting collar that also forms the flange region.

8. A vehicle rim according to one of claims I to 7, characterized in that a rim star consisting of metal is fastened to the flange region by means of a screw connection (16).

9. A vehicle rim according to one of claims I to 8, characterized in that the flange region is penetrated by screw-receiving holes at a point at which the collars of the third sub-preform and of the fourth sub-preform overlap radially.

10. A vehicle rim according to one of claims 1 to 9, characterized in that a filler core is inserted in a ring space between the second sub-preform , on the one hand, and the third sub-preform and/or the fourth sub-preform , on the other hand.

11. A method of manufacturing a rim body of fiber composite material for a vehicle rim, wherein a first sub-preform having a reinforcing fiber is arranged to form a first axial end of the rim body

, and a second sub-preform is inserted into a connecting cavity of the first sub-preform , wherein the second sub-preform extends axially away from the first sub-preform to a second axial end of the rim body , and wherein a third sub-preform is attached to the first sub-preform and/or the second sub-preform , so that the latter co-forms a radially inwardly projecting flange region prepared for connection of a rim star.

[_WBetalAVS_L_71_828_20230426083405__]

1/4 01 May 2023 2023202667

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Fig. 1