SUSPENSION ROD MANUFACTURED BY ADDITIVE MANUFACTURING TECHNOLOGY

Description

Technical field of the invention

[0001] The present invention relates to a motor vehicle suspension rod.

[0002] The invention relates more particularly to a suspension rod obtained by an additive manufacturing technique using a metal or a polymer / composite. Technical background

[0003] As is known, a suspension rod is, for example, made by forging, particularly from aluminum alloy.

[0004] Known designs and this type of production techniques allow the connecting rod to meet the various constraints linked on the one hand to the resistance of the connecting rod and also to its fusibility capacity.

[0005] The invention aims to propose a low-mass connecting rod which satisfies these different types of design constraints.

[0006] EP3524450A1 discloses a suspension link as in the preamble of claim 1. DE102017002581 discloses a known suspension arm. Summary of the invention

[0007] The invention provides a motor vehicle suspension rod comprising: a first longitudinal end, in particular configured to be connected to another component of the suspension or to an element of the vehicle body; a second longitudinal end, in particular configured to be connected to another component of the suspension or to an element of the vehicle body; and an elongated hollow body which extends between the first end and the second end, characterized in that: the connecting rod 10 is produced in a single piece by an additive manufacturing technique; the elongated hollow body 12 is delimited by an elongated envelope; and the hollow body is internally reinforced by a series of crosspieces, in particular adjacent, of reinforcement which extend in a plane parallel to a longitudinal axis connecting the first longitudinal end to the second longitudinal end.

[0008] It is thus possible to reinforce the part locally while allowing a reduction in the quantity of material in the unstressed or least stressed areas or portions.

[0009] This design also provides a fusibility function which is achieved by large deformation without breaking the connecting rod.

[0010] According to other characteristics of the invention: each reinforcing crosspiece consists of a pair of reinforcing crosspieces arranged in a cross; the casing of the hollow body comprises at least one elongated side wall, and the reinforcing crosspieces are formed in relief from a portion of the internal face of the at least one side wall; for example, four reinforcing crosspieces are arranged in high-stress areas in order to reduce the plasticization of the connecting rod.; the casing of the elongated hollow body comprises at least two opposite elongated side walls, and the reinforcing crosspieces are formed in relief from a portion of the internal face of each of the at least two side walls;each portion of the internal face of an elongated side wall extends longitudinally from a longitudinal end of the elongated hollow body; the elongated body comprises a series of lightening holes which are formed in longitudinal portions of the elongated casing which are devoid of reinforcing crosspieces; the reinforcing crosspieces extend in a longitudinal plane internal to the elongated casing; the longitudinal plane is a median longitudinal plane of the elongated body; the elongated body may comprise an internal reinforcing core which extends longitudinally inside the casing, with at least one longitudinal portion of this internal reinforcing core being constituted by the reinforcing crosspieces; the internal reinforcing core is shaped into an internal plate which connects together two opposite walls of the casing and it may comprise recesses, a series of which delimits the reinforcing crosspieces;the elongated body comprises a series of lightening holes which are formed at least in portions of at least one of the two walls, between connection zones of the reinforcing crosspieces with the elongated envelope.; Brief descriptions of the figures

[0011] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: [ Fig. 1 ] - there figure 1 is a perspective view of a first example of embodiment of a suspension rod according to the invention; [ Fig.2 ] - there figure 2 is a cross-sectional view through a transverse plane of the elongated body of the suspension link shown in figure 1 ; [ Fig.3 ] - there figure 3 is a sectional view through a median longitudinal plane of the elongated body of the suspension link shown in figure 1 ; [ Fig.4] - there figure 4 is a view analogous to that of the figure 1 which represents a second example of embodiment of a suspension rod according to the invention; [ Fig.5 ] - there Figure 5 is a perspective and sectional view through a transverse plane of the suspension link shown in figure 4 ; [ Fig.6 ] - there figure 6 is a perspective view and section through a median longitudinal plane of the suspension link shown in figure 4 ; [ Fig.7 ] - there figure 7 is a plan view and section through a median longitudinal plane of the suspension link shown in figure 4 . Detailed description of the invention

[0012] For the description of the invention and the understanding of the claims, the vertical, longitudinal and transverse orientations according to the reference V, L, T indicated in the figures, the longitudinal L and transverse T axes of which extend in a horizontal plane, will be adopted as a non-limiting example and without limiting reference to Earth's gravity.

[0013] By convention, the longitudinal axis L is oriented from back to front.

[0014] In the following description, identical, similar or analogous elements will be designated by the same reference numbers. First example of realization Figures 1 to 3.

[0015] We represented at the figure 1a first example of embodiment of a suspension rod 10 which is essentially constituted by an elongated body 12 which extends longitudinally between a first end 14 and a second end 16 for connecting the rod 10 to different components (not shown) belonging to other mobile elements of the suspension of a motor vehicle wheel or to the body structure and for example to a cradle.

[0016] Each end 14, 16 is here shaped into a cylindrical sleeve with axis A1, A2.

[0017] As a non-limiting example, the connecting rod 10 has a general symmetry of design with respect to a median vertical and longitudinal plane PLM represented in the figure 2 and the axes A1 and A2 are orthogonal to this plane of symmetry.

[0018] Thus, the body 12 is an elongated body along the general longitudinal direction D passing through the two axes A1 and A2, and which extends from the first rear end 14 to the second front end 16 along the orientation of the longitudinal axis L.

[0019] The suspension link 10 is preferably produced in a single piece using an additive manufacturing technique, also called “3D printing”.

[0020] The elongated body 12 is a hollow body which is in the form of an elongated envelope 18.

[0021] To the figure 2 , the general profile of the envelope 18 has been represented.

[0022] This profile is presented in the form of a closed quadrilateral which is here a trapezoid comprising: two longitudinal and opposite side walls 20; a longitudinal upper wall 22 and a longitudinal lower wall 24 generally horizontal.

[0023] Without limitation, the walls 20 and 24 are substantially flat, while the upper wall 22 here has a curved profile whose convexity is oriented towards the interior 26 of the envelope 18.

[0024] In section, with respect to the mean horizontal plane in which the upper wall 22 extends, each side wall 20 forms an acute angle alpha. Similarly, with respect to the mean horizontal plane in which the lower wall 24 extends, each side wall 20 forms an internal and acute angle beta.

[0025] The average thickness “E” of the different walls 20, 22 and 24 can vary along the elongated body 12.

[0026] As a non-limiting example, the values ​​of these geometric parameters are as follows: the thickness E is less than or equal to 10 millimeters the angle alpha is between ten and five degrees of angle the angle beta is between forty-five and one hundred degrees of angle the number of reinforcing crosspieces is determined according to the length of the elongated body 12 and the determined reinforcement performances expected.

[0027] From the first rear end 14, the hollow body 12 is reinforced by a series of reinforcing crosspieces 30 which are formed in relief, here on the internal face 21 of each of the two opposite side walls 20.

[0028] In section, each reinforcing crosspiece 30 has, for example, a trapezoidal profile.

[0029] The reinforcing crosspieces 30 are associated two by two to form a series of reinforcing crosspieces 32.

[0030] So, as we can see in the figure 3, from the first end 14, a rear longitudinal portion of the internal face 21 of each side wall 20 comprises four successive and adjacent crosspieces 32.

[0031] Two reinforcing crosspieces 30 of the same crosspiece 32 are substantially orthogonal.

[0032] The opposite upper and lower ends of each reinforcing crosspiece 30 are respectively adjacent to the inner face 23 of the upper wall 22 and to the inner face 25 of the lower wall 24.

[0033] The reinforcing crosspieces 30 formed in relief on the internal faces 21 can extend up to the level of the median vertical and longitudinal plane PLM.

[0034] As a non-limiting example, the following are shown: figures 1 And 3 lightening holes 34 formed through the wall of the elongated casing 18.

[0035] In each side wall 20, the relief holes 34 are here produced in the form of a series of three holes 34.

[0036] The lightening holes 34 are formed in a portion of each side wall 20 not comprising reinforcing crosspieces 32, and here by way of example in the front portion which extends longitudinally rearward from the second front end 16.

[0037] Without departing from the scope of the invention, both reinforcing crosspieces 32 and lightening holes 34 may be formed in other portions and in other portions of the elongated body 18.

[0038] As we can see the figure 1 , the additive manufacturing technique, which can be metal or polymer / composite, implemented for the production of the suspension link 10 makes it possible to produce simultaneously and in a single piece accessory parts such as for example the external fixing lug 36. Second example of realization Figures 4 to 7.

[0039] The second example of realization illustrated in figures 4 to 7 is essentially distinguished from the previous one in that the reinforcing crosspieces 30 and the reinforcing crosspieces 32 which they constitute are constituted by a portion of a central core 40 in the form of an internal plate.

[0040] The general definition of the sectional profile of the elongated hollow envelope 18 is the same as that described in detail with reference to the first exemplary embodiment.

[0041] By way of non-limiting example, the values ​​of these geometric parameters of the wall of the elongated envelope 18 are as follows: the thickness E is less than or equal to 10 millimeters the angle alpha is between ten and five degrees of angle the angle beta is between forty-five and one hundred degrees of angle the geometry and the extent of the elongated central core 40 are determined according to the expected reinforcement performances.

[0042] The elongated body 12 is reinforced by the central core 40.

[0043] The central core 40 is constituted by a central plate made in a single piece with the hollow elongated body 12.

[0044] The central core 40 is arranged in the median longitudinal plane PLM and, as can be seen in particular in the figure 7 , it extends here internally over the entire length of the elongated envelope 18 between its two rear 14 and front 16 ends.

[0045] The upper and lower longitudinal edges of the central core 40 extend along the entire length of the inner face 23 of the upper wall 22 and the inner face 25 of the lower wall 24, respectively.

[0046] In this exemplary embodiment, and without limitation, the reinforcing crosspieces 32 belong to the front portion of the central core 40 which extends longitudinally towards the rear from the front end 16.

[0047] The reinforcing crosspieces 32, here three in number, are produced by means of recesses 42 which are formed in the upper and lower longitudinal edges of the central core 40, in the corresponding front portion of the latter.

[0048] To the figure 7, the three crosspieces 32 are materialized by three crosses drawn in dotted lines. The tops of the equivalent of the reinforcing crosspieces 30 according to the first embodiment meet at the upper and lower longitudinal edges to constitute a series of three adjacent reinforcing crosspieces 32.

[0049] Without limitation, and as can be seen in the figure 7 , the central core 40 is extended longitudinally towards the rear - beyond the front portion reinforced by the reinforcing crosspieces 32 - by a rear portion which also participates in the reinforcement function.

[0050] Just as the profile and the number of recesses 42 determine the number and the reinforcement capacity of the reinforcing crosspieces 32, the rear portion of the central core 40 can be solid, or else openwork as is for example illustrated by means of a series of holes or slots 44, here three in number.

[0051] With regard to the production of lightening holes in the elongated envelope 18, there is shown, without limitation, in this second embodiment, on the one hand a series of ten lightening holes 34 formed in each side wall 20.

[0052] These series are completed by another series of holes and lights 33 formed in the upper wall 22, and by another series of holes and lights 35 formed in the lower wall 24.

[0053] As part of the impact resistance and impact energy absorption performance of a rear axle wheel, it is necessary to have sufficient mechanical strength of the connecting rod for low energy impacts, but also controlled fusibility for high energy impacts. At the same time, the connecting rod must not be oversized for reasons of mass and cost. The connecting rod part must also meet other requirements such as endurance.

[0054] The implementation of a metal or polymer / composite 3D printing process makes it possible to limit the mass and to integrate several functions into the part to meet the minimum mass objective and thus limit the vehicle's consumption. The design according to the invention makes it possible, for an existing geometry and dimensions of a suspension link, to achieve the other services (non-damaging impact and endurance).

Claims

1. Motor vehicle suspension link (10) comprising: - a first longitudinal end (14); - a second longitudinal end (16) connected to the first longitudinal end by a longitudinal axis (D); - and an elongate hollow body that extends longitudinally between the first end (14) and the second end (16), - the link (10) is made in a single piece via an additive manufacturing technique; - the elongate hollow body (12) is delimited by an elongate envelope (18); characterized in that the elongate hollow body (12) is reinforced internally by a series of reinforcing crosspieces (32) that extend in a plane parallel to the longitudinal axis (D) connecting the first longitudinal end (14) to the second longitudinal end (16).

2. Suspension link (10) according to Claim 1, characterized in that each reinforcing crosspiece is constituted by a pair of reinforcing crossmembers arranged in a cross.

3. Link (10) according to Claim 1, characterized in that the elongate envelope (18) of the elongate hollow body (12) comprises at least one elongate lateral wall (20), and in that the reinforcing crosspieces (32) are formed in relief from a portion of the internal face (21) of said at least one lateral wall (20).

4. Link (10) according to Claim 3, characterized in that the elongate envelope (18) of the elongate hollow body (12) comprises at least two opposite elongate lateral walls (20), and in that said reinforcing crosspieces (32) are formed in relief from a portion of the internal face (21) of each of said at least two lateral walls (20).

5. Link (10) according to either one of Claims 3 and 4, characterized in that each said portion of the internal face (21) of an elongate lateral wall (20) extends longitudinally from a longitudinal end of the hollow body (12).

6. Link (10) according to any one of Claims 3 to 5, characterized in that the elongate hollow body (12) comprises a series of lightening holes (34) that are formed in longitudinal portions of the elongate envelope (18) that are free of reinforcing crosspieces (32).

7. Link (10) according to Claim 1, characterized in that said reinforcing crosspieces (32) extend in a longitudinal plane internal to the elongate envelope (18), in particular in a median longitudinal plane of the hollow body (12).

8. Link (10) according to any one of the preceding claims, characterized in that the elongate hollow body (12) comprises an internal reinforcing web (40) that extends longitudinally inside the elongate envelope (18), and in that at least one longitudinal portion of this internal reinforcing web (40) is constituted by said reinforcing crosspieces (32).

9. Link (10) according to Claim 8, characterized in that the internal reinforcing web (40) is shaped as an internal plate that connects two opposite walls (22, 24) of the elongate envelope (18) to each another and that comprises cutouts (42), a series of which delimits said reinforcing crosspieces (32).

10. Link (10) according to the preceding claim, characterized in that the elongate hollow body (12) comprises a series of lightening holes (33, 35) that are formed at least in portions of at least one of said two walls (22, 24), between zones of connection of said reinforcing crosspieces (32) with the elongate envelope (18) .

11. Link according to any one of the preceding claims, characterized in that, in section on a transverse plane, the elongate hollow body is in a closed form, in particular in the form of a closed quadrilateral, in particular in the form of a trapezium.