Suspension organs

Abstract

A road vehicle suspension component for converting at least a portion of the vibrations and / or mechanical stresses into electricity, the suspension component comprising at least one suspension element or at least one interface element, configured to participate in the attachment of at least one suspension element of the vehicle, and at least one continuous two-dimensional sheet (1) integrated into or covering a surface of the suspension element or interface element, wherein said at least one two-dimensional sheet (1) comprises a plurality of individual piezoelectric elements (3) arranged in the two-dimensional sheet (1), and wherein said at least one two-dimensional sheet (1) further comprises an electrical circuit (4) connecting said individual piezoelectric elements (3) to each other. Fig. 5.

Description

Title of the invention: Suspension component technical field

[0001] The present description relates to a suspension component for road vehicles enabling the conversion of at least part of the vibrations and / or mechanical stresses into electricity. Previous technique

[0002] Vehicle suspension components, including in particular coil springs and anti-roll bars, are designed to exhibit elastic behavior in order to reduce the jolts and vibrations felt inside the vehicle cabin. These suspension components are therefore subject to significant deformations and vibrations during operation. This is also the case for the interface elements used to attach these suspension components to the vehicle's chassis or running gear.

[0003] Naturally, these deformations and vibrations normally result in significant energy losses, which are dissipated primarily through friction. For a combustion engine vehicle, it is estimated that 3 to 15% of the energy developed in the engine is dissipated in the vehicle's suspension, with losses rising to 8 to 39% if only the mechanical energy actually produced by the engine is considered, i.e., if losses related to exhaust (33%) and engine cooling (29%) are excluded.

[0004] It would therefore be desirable to be able to recover at least some of this energy dissipated in the suspension. To this end, several solutions have already been proposed in the past, but they are not entirely satisfactory.

[0005] For example, some solutions aim to install an electric generator at the level of the suspension coil spring or its shock absorber, by converting, for example, the hydraulic pressure of the shock absorber into torque in a hydraulic motor or by converting the linear displacement of the spring or shock absorber into rotation using a rack and pinion. However, these solutions require adding heavy and bulky components, which ultimately reduces the expected energy recovery gain.

[0006] Other solutions propose recovering this displacement energy by induction, for example by installing a coil, attached to one end of the spring, around a magnet, attached to the other end of the spring. However, these solutions are also bulky and difficult to implement in practice.

[0007] Finally, other solutions propose to implement one or more Piezoelectric elements are placed on the suspension element or on an element crushed by it. However, to date, known solutions using piezoelectric elements do not produce a truly usable current. Indeed, in most known configurations, the piezoelectric element is installed at a point and therefore generates only a small potential difference, and only when it is stressed in the correct direction. These piezoelectric elements are thus generally relegated to compression sensor functions without any real potential for energy recovery.

[0008] There is therefore a real need for a suspension device that can convert at least part of the vibrations and / or mechanical stresses into electricity and that is free, at least in part, from the disadvantages inherent in the aforementioned configurations. Description of the invention

[0009] The present description relates to a suspension component for a road vehicle, comprising at least one suspension element, exhibiting elastic behavior so as to act as a suspension spring during vehicle operation, or at least one interface element, configured to participate in the attachment of at least one vehicle suspension element exhibiting elastic behavior so as to act as a suspension spring during vehicle operation, and at least one continuous, two-dimensional sheet integrated into the suspension element or interface element or covering at least one interface surface of the suspension element or interface element, said interface surface being intended to be in contact with another component of the vehicle during vehicle operation, wherein said at least one two-dimensional sheet comprises a plurality of individual piezoelectric elements arranged in the two-dimensional sheet so as to convert into electricity at least a portion of the vibrations and / or mechanical stresses experienced by the suspension element during vehicle operation, and in which said at least one two-dimensional sheet further comprises an electrical circuit, connecting said individual piezoelectric elements together so as to collect the electricity produced by said piezoelectric elements.

[0010] Thanks to the proposed configuration, in which several piezoelectric elements are supported and distributed in a two-dimensional array, it is possible to recover, on average, a satisfactory and usable electrical voltage. Indeed, since Since piezoelectric elements are distributed throughout the aquifer, the probability that at any given time at least some of them will be activated, and thus generate a potential difference, increases significantly. The recoverable potential difference, and its stability over time, increases all the more as the aquifer contains a large number of piezoelectric elements and as the aquifer covers a large portion of the interface surface. In particular, by distributing the piezoelectric elements over such a large area, the recovery of different types of stresses is facilitated, as these stresses are not exerted with the same magnitude in every zone.

[0011] In particular, such a configuration makes it possible to adjust, individually or in sets, the parameters of the piezoelectric elements, in particular their orientations, in order to adapt them specifically to the constraints that they will be subjected to locally.

[0012] Furthermore, the use of such individual piezoelectric elements connected together by an electrical circuit makes it possible to capture and amplify, depending on the number of piezoelectric elements, vibrations which are usually difficult to value due to their low amplitude.

[0013] Furthermore, such a piezoelectric mat is easy to implement and can cover a large area without increased difficulty. Indeed, the piezoelectric mat can be prepared in advance and simply installed during the assembly of the suspension element; it can also be directly integrated into the suspension element or the interface element during its manufacture.

[0014] In particular, such a configuration adds very little mass and benefits from minimal bulk: it is therefore possible to put such a piezoelectric pad into an already existing suspension element design without particularly important adaptation.

[0015] In the present description, it is understood that a two-dimensional sheet is a sheet extending in two orthogonal directions, a principal direction and a transverse direction, the thickness of the two-dimensional sheet being negligible compared to each of these two directions. It is further understood that, since the sheet can be flexible, these two directions of extension can be curvilinear. In particular, it is understood that one of these two directions can close on itself and thus form a loop: this is notably the case when the sheet forms a tubular sheath, the transverse direction of the sheet closing on itself, or when the sheet forms a ring, the principal direction of the sheet closing on itself.

[0016] In certain embodiments, the suspension member comprises a plurality of two-dimensional sheets equipping said suspension element or interface element. These two-dimensional sheets may equip the same interface surface or different interface surfaces. The configuration of these sheets allows, in fact, for easily install several, in different locations, to maximize the amount of energy recovered by particularly targeting areas where stresses and / or vibrations are greatest.

[0017] In certain embodiments, said two-dimensional mats are connected to each other in series or in parallel. A hybrid configuration combining series and parallel connections is also possible.

[0018] In certain embodiments, at least one, and preferably each, two-dimensional sheet has a length of at least 3 cm, preferably at least 5 cm, and even more preferably at least 10 cm, in a principal direction of extension. The larger the sheet, the greater the surface area it covers, which increases, on the one hand, the number of piezoelectric elements that can be deployed and, on the other hand, the spatial distribution of the piezoelectric elements and therefore the probability that at any given time at least some of them will produce energy.

[0019] In certain embodiments, at least one, and preferably each, two-dimensional sheet has a thickness less than or equal to 5 mm, preferably less than or equal to 2 mm, and even more preferably less than or equal to 1 mm. The overall size of the sheet is thus very small and does not practically alter the dimensions of the suspension element or the interface element.

[0020] In certain embodiments, at least one two-dimensional sheet comprises at least 10, preferably at least 50, and even more preferably at least 100, individual piezoelectric elements. The greater the number of piezoelectric elements, the higher the average generated voltage and the greater the probability that at least some of them are correctly oriented to effectively convert local stresses and / or vibrations.

[0021] In certain embodiments, each individual piezoelectric element has a length of 5 mm or less, preferably 2 mm or less, and even more preferably 1 mm or less. The smaller the piezoelectric element, the less voltage it generates, but the higher the piezoelectric element density can be, which promotes the local recovery of even the smallest stresses, including vibrations. Thus, overall, a stable, continuous, and ultimately greater electrical generation is obtained.

[0022] In certain embodiments, the two-dimensional sheet comprises a piezoelectric element density greater than or equal to 50 / dm², preferably greater than or equal to 300 / dm². Indeed, the higher the piezoelectric element density, the greater the local recovery of even the smallest stresses, including vibrations. Thus, overall, a stable, continuous, and ultimately greater electrical generation is obtained.

[0023] In some embodiments, at least one individual piezoelectric element comprises a piezoelectric material selected from the following: lead zirconate titanoate (PZT), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), lead-free artificial.

[0024] In certain embodiments, all the individual piezoelectric elements of a two-dimensional sheet are oriented in the same direction. Such a configuration is the simplest to design and implement. It is understood here that this direction of orientation lies in the curvilinear plane of the sheet. In particular, when the sheet has a sheath or ring geometry, this same direction of orientation can close upon itself and thus form, for example, circles.

[0025] In certain embodiments, the individual piezoelectric elements of a two-dimensional sheet are arranged in a plurality of sets, all the individual piezoelectric elements of a set being aligned in the same direction. Such sets, each preferably comprising at least ten piezoelectric elements, allow the orientation of the piezoelectric elements to be adjusted to the constraints actually present in the area considered, thereby increasing the average amount of energy recovered.

[0026] In certain embodiments, said orientation direction is parallel to the main extension direction of the two-dimensional sheet concerned.

[0027] Suspension member wherein said orientation direction is inclined with respect to the principal extension direction of the two-dimensional sheet concerned. Such a configuration is particularly effective when the stresses experienced are exerted mainly in a direction different from the principal extension direction of the sheet; this is notably the case for a helical spring.

[0028] In certain embodiments, the angle formed between said orientation direction and the principal extension direction of the two-dimensional sheet concerned is between 20 and 70°, preferably between 40 and 50°. This angle range is particularly suitable for helical springs.

[0029] In certain embodiments, the orientation of the individual piezoelectric elements varies depending on their position on the suspension element or the interface element. This allows the orientation of the piezoelectric elements to be adjusted to the actual stresses present in the area considered, thereby increasing the average amount of energy recovered.

[0030] In certain embodiments, the individual piezoelectric elements of at least one set, preferably of all the individual piezoelectric elements, of at least one two-dimensional array, are arranged according to a two-dimensional Bravais lattice, preferably orthorhombic. Such an arrangement is easy to design and to be wired.

[0031] In some embodiments, the individual piezoelectric elements of at least one set, preferably of all the individual piezoelectric elements, of at least one two-dimensional array, are connected in parallel within a given row and in series from one row to another.

[0032] In certain embodiments, at least one two-dimensional pad comprises a support layer, including the electrical circuit, on which the piezoelectric elements are mounted. This support layer may, in particular, be a flexible printed circuit board.

[0033] In certain embodiments, at least one two-dimensional sheet comprises a protective, insulating layer covering the individual piezoelectric elements and the electrical circuit of said two-dimensional sheet. This protective layer isolates the piezoelectric elements and the electrical circuit, thereby reducing the risk of short circuits, and protects these same elements against potential mechanical damage, such as wear or impacts.

[0034] In some embodiments, the protective layer comprises a material selected from the following: silicone, polyethylene terephthalate (PET), polyester (PES), polyetheretherketone (PEEK) or epoxy.

[0035] In some embodiments, the protective layer comprises reinforcing fibers. These fibers may be short or long; these fibers may, in particular, be glass fibers or carbon fibers.

[0036] In some embodiments, the two-dimensional mat comprises several superimposed layers, each layer comprising a plurality of individual piezoelectric elements and an electrical circuit. The electrical circuits of the different layers can be interconnected, for example in series or in parallel. Each layer can be configured in the same way or in different ways.

[0037] In some embodiments, the main direction of extension of the two-dimensional sheet is closed on itself, forming an annular geometry.

[0038] In some embodiments, the transverse direction of extension of the two-dimensional sheet is closed on itself, forming a tubular geometry.

[0039] In some embodiments, the two-dimensional sheet is attached, preferably by gluing, to the suspension element or the interface element.

[0040] In some embodiments, the suspension element or the interface element is overmolded onto the two-dimensional sheet.

[0041] In some embodiments, the two-dimensional sheet is threaded around the suspension element or the interface element.

[0042] In certain embodiments, the two-dimensional sheet is intercalated between two components of the interface element, for example between a reinforcement and a elastomer layer in contact with the suspension element.

[0043] In some embodiments, the suspension element is a stabilizer bar, and said at least one two-dimensional sheet covers at least a portion of the surface of the stabilizer bar intended to be held by a bearing of the vehicle.

[0044] In some embodiments, the interface element is a bearing configured to be mounted around a stabilizer bar of the vehicle.

[0045] In certain embodiments, said at least one two-dimensional sheet covers at least a portion of the internal surface of the bearing, intended to hold the stabilizer bar.

[0046] In certain embodiments, said at least one two-dimensional layer is intercalated between two components of the bearing, preferably between a reinforcement and an elastomer layer in contact with the stabilizer bar.

[0047] In some embodiments, the bearing comprises at least one flange having a cradle portion and two fixing lugs, and said at least one two-dimensional sheet covers at least the cradle portion, and preferably also the internal surface of the fixing lugs.

[0048] In some embodiments, the bearing comprises at least one plywood, separate from the flange and configured to be brought against the stirrup, and at least one second two-dimensional sheet covers at least a portion of the internal surface of the plywood.

[0049] In certain embodiments, the suspension element comprises at least one fixing eyelet, and said at least one two-dimensional sheet covers at least a portion of the internal surface of the fixing eyelet. In such a case, the suspension element may, for example, be a stabilizer bar or a leaf spring.

[0050] In some embodiments, the interface element is a bearing configured to be mounted in an eyelet of a vehicle suspension element, for example a leaf spring or a stabilizer bar.

[0051] In certain embodiments, said at least one two-dimensional sheet covers at least a portion of the internal or external surface of the bearing.

[0052] In certain embodiments, said at least one two-dimensional layer is intercalated between two components of the bearing, preferably between a reinforcement and an elastomer layer.

[0053] In some embodiments, the suspension element is a helical spring, and said at least one two-dimensional sheet covers at least a portion of the external surface of the helical spring.

[0054] In certain embodiments, said at least one two-dimensional sheet covers at least one end portion of the helical spring, preferably on the minus 5 cm, preferably still at least 10 cm. The end portion of the helical spring is in fact the portion which undergoes the most stress, in particular because it is in contact with a rigid element of the vehicle.

[0055] In certain embodiments, said at least one two-dimensional sheet surrounds said at least one portion of the external surface of the helical spring in the manner of a sheath. Such a sheath can then also play a protective role for the helical spring.

[0056] In certain embodiments, said at least one two-dimensional sheet covers the entire external surface of the helical spring.

[0057] In some embodiments, the interface element is a helical spring support element configured to be mounted at one end of a helical spring and locked onto a cup.

[0058] In certain embodiments, said at least one two-dimensional sheet covers at least a portion of the external surface of the support element, intended to be in contact with the cup.

[0059] In certain embodiments, said at least one two-dimensional sheet is intercalated between two components of the support element, preferably between a portion of the support in contact with the helical spring and a portion of the base in contact with the cup.

[0060] The aforementioned features and advantages, as well as others, will become apparent from the following detailed description of examples of suspension components. This detailed description refers to the accompanying drawings. Brief description of the drawings

[0061] The attached drawings are schematic and are intended primarily to illustrate the principles of the exposition.

[0062] In these drawings, from one figure to another, identical elements (or parts of elements) are identified by the same reference numerals. In addition, elements (or parts of elements) belonging to different embodiments but having a similar function are identified in the figures by numerical reference numerals incremented by 100, 200, etc.

[0063] [Fig. 1] [Fig. 1] is a front view diagram of a first example of a piezoelectric sheet two-dimensional electrical.

[0064] [Fig.2] The [Fig.2] is a cross-sectional diagram of the piezoelectric sheet of the [Fig.1].

[0065] [Fig.3] Fig.3 is a front view diagram of a second example of a piezoelectric sheet two-dimensional electrical.

[0066] [Fig.4] Fig.4 is a perspective view of a first example of an organ of suspension including a stabilizer bar and bearings.

[0067] [Fig.5] The [Fig.5] is an exploded view of a bearing of the [Fig.4].

[0068] [Fig.6] Fig.6 is a perspective view of a second example of an organ of suspension comprising a leaf spring and bearings.

[0069] [Fig.7] The [Fig.7] is an exploded view of a bearing of the [Fig.6].

[0070] [Fig.8] Fig.8 is a perspective view of a third example of an organ of suspension comprising a helical spring and a support element.

[0071] [Fig.9] The [Fig.9] is a cross-sectional view of the support element of the [Fig.8].

[0072] [Fig. 10] The [Fig. 10] is a perspective view of a fourth example of a suspension member comprising a helical spring. Description of the implementation methods

[0073] To make the explanation more concrete, examples of suspension components are described in detail below, with reference to the accompanying drawings. It should be noted that the invention is not limited to these examples.

[0074] Figure 1 schematically represents a first example of a piezoelectric sheet 1 as described above. Such a piezoelectric sheet 1 is two-dimensional, that is, it extends along two orthogonal directions: the principal direction P of the sheet 1, corresponding to its direction of greatest length, and the transverse direction T of the sheet 1, corresponding to its direction of shortest length, with a thickness negligible compared to these two directions of extension. The piezoelectric sheet 1 comprises a support layer 2 on which are mounted a plurality of individual piezoelectric elements 3 connected to each other by an electrical circuit 4.

[0075] The electrical circuit 4 here takes the form of conductive tracks traced on the surface of the support layer 2, the piezoelectric elements 3 then being soldered onto the connectors of the electrical circuit 4. The support layer 2 can in particular take the form of a flexible printed circuit, made for example of polyimide or polyetheretherketone (PEEK).

[0076] Piezoelectric elements 3 can take different forms, all having in common the ability to generate a voltage difference between their two poles when they undergo deformation. For example, piezoelectric elements may include lead zirconate titano (PZT).

[0077] The piezoelectric elements 3 are also small enough to allow the piezoelectric sheet 1 as a whole to be at least partially flexible and to allow a high density of piezoelectric elements 3. Thus, in the present example, the piezoelectric elements 3 are 5 mm long, 1 mm wide and 1 mm high; the density of the piezoelectric elements 3 is 500 units per dm2.

[0078] The piezoelectric elements 3 can be arranged in different ways. In this first example, the piezoelectric elements 3 are arranged according to an orthorhombic lattice, that is to say according to regular and orthogonal rows and columns.

[0079] The piezoelectric elements 3 can be oriented in different ways. In this first example, all the piezoelectric elements 3 are oriented in the same direction, which constitutes the orientation direction O of the piezoelectric sheet 1, this direction being parallel to the main extension direction P of the piezoelectric sheet 1.

[0080] However, in a second example, shown in [Fig.3], all the piezoelectric elements 103 can be oriented in the same direction, but this orientation direction O can form a non-zero angle 0 with the principal direction P of the sheet 1. Thus, in this second example, this angle 0 measures 20°.

[0081] In the first example, as in the second example, the piezoelectric elements 3 of the same column are connected in parallel, while the different columns of the network 1 are connected in series. At each end of the network 1, the electrical circuit 4 terminates at a terminal 5-, 5+, one of the terminals constituting a negative terminal 5- while the other constitutes a positive terminal 5+. Each terminal 5 can then be connected to a cable 6 for collecting the electricity produced by the piezoelectric network 1.

[0082] Furthermore, as can be seen in [Fig.2], the piezoelectric mat 1 further comprises an insulating protective layer 7 covering the electrical circuit 4 and each of the piezoelectric elements 3. For example, this protective layer 7 can be made of silicone and include glass fibers.

[0083] Thus, by using a large number of small individual piezoelectric elements 3 distributed across a layer 1, it is possible to convert into electricity the mechanical stresses experienced by the piezoelectric layer 1, as well as the vibrations passing through it. Since this electrical voltage is inherently highly variable over time, depending on the amplitude of the stresses and vibrations experienced, it is preferable to connect an electrical rectifier downstream of the piezoelectric layer 1 in order to smooth out the fluctuations in the voltage generated by the piezoelectric layer 1.

[0084] Figure 4 shows a first example of a vehicle suspension component 10 including such a piezoelectric element 1. It is a stabilizer assembly 10 comprising a stabilizer bar 11, solid or hollow, painted or unpainted, the central part 12 of which is equipped with two bearings 13. The bearings 13 are intended to be fixed to the vehicle chassis, while the ends 14 of the stabilizer bar 11 each have an eyelet 15, the eyelets 15 being intended to be fixed to parts of the vehicle attached to each wheel of the same axle, in particular the suspension triangle of each wheel of the axle.

[0085] Fig. 5 represents such a bearing 13. The bearing 13 comprises a flange 20, a plywood 30 and an elastomer layer 19.

[0086] The flange 20 includes first of all an armature 20a having a general U-shape and comprising two retaining lugs 21 connected by a hoop 25 so as to form a groove 26. This armature 20 is symmetrical with respect to its main axis A which more broadly constitutes the main axis of the bearing 13.

[0087] Each retaining lug 21 extends laterally from the base of the hoop 25, perpendicular to the main axis A. Each retaining lug 21 has a bearing surface 22, forming the bearing surface of the flange 20, and a through bore 23, with axis C perpendicular to the bearing surface 22 and therefore parallel to the main axis A. Each bore 23 is provided with a metal bushing 24 passing through the retaining lug 21 and extending onto the bearing surface 22 of the flange 20 for a length substantially equal to the thickness of the plywood 30.

[0088] The groove 26, generally U-shaped, is also symmetrical with respect to the main axis A. It has a semi-cylindrical bottom portion, forming a cradle portion 27, flanked by two flat lateral walls 28 opening onto the bearing surface 22 of the flange 20. The semi-cylindrical cradle portion 27 is directed along an axis B orthogonal to the axis A and corresponding to the direction of extension of the stabilizer bar 11 when the bearing 13 is mounted.

[0089] The reinforcement 20a of the flange 20 is made by molding and injection of glass fiber reinforced polyamide 66. These glass fibers are short, with a length between 3 and 3.2 mm and a diameter between 0.2 and 0.25 mm. The metal bushings 24 are inserted into the mold of the reinforcement 20a before the injection of the thermoplastic material. In some examples, the bushings 24 may include annular ridges to lock their positions within the reinforcement 20a once the material has solidified.

[0090] The flange 20 further comprises a first piezoelectric layer 80, analogous to the piezoelectric layer 1 presented above, conforming to the geometry of the lower surface of the armature 20a: the first piezoelectric layer 80 thus comprises two lateral tabs 81, covering the bearing surface 22 of each retaining tab 21 of the armature 20a, connected by a central arch 85, conforming to the shape of the groove 26 of the armature 20a. A notch 82 is made in each lateral tab 81 so as to allow the bushings 24 of the flange 20 to pass through.

[0091] This first piezoelectric layer 80 can be brought against the lower surface of the armature 20a after obtaining the latter, for example by gluing, or can be installed beforehand in the mold of the armature 20a which can then be overmolded over the piezoelectric layer 80.

[0092] The plywood 30 has a general plate shape. It comprises a frame 30a having a flat upper face 31 and a flat lower face 32 connected by a peripheral side wall 33. The frame 30a is also symmetrical with respect to the main axis A of the bearing 13. More precisely, the dimensions of the frame 30a correspond to the external dimensions of the flange 20 such that the plywood 30 can be placed against the bearing surface 22 of the flange 20, or more precisely against the piezoelectric layer 80 covering it, by extending exactly the contours of the flange 20.

[0093] In the present example, the plywood 30 is essentially flat; however, in other examples, it could have other shapes, for example a cradle shape depending on the shape of the flange and / or the chassis of the vehicle.

[0094] More particularly, the reinforcement 30a of the plywood 30 has a sealing portion 36 framed by two assembly portions 37: each assembly portion 37 is provided to coincide with a retaining tab 21 of the flange 20 while the sealing portion 36 is provided to span the groove 26 of the flange 20 and thus close it.

[0095] Each assembly portion 37 has a bore 34 coinciding with the fixing bore 23 of the corresponding retaining lug 21 of the flange 20: its diameter corresponds substantially, that is to say within a clearance, to the external diameter of the sleeve 24 so that the part of the sleeve 24 protruding on the bearing surface 22 of the flange 20 can engage in this bore 34.

[0096] The reinforcement 30a of the plywood 30 is made by molding and injection of glass fiber reinforced polyamide 66. The glass fibers used to reinforce the polyamide of the plywood 30 are similar to those used for the flange 20.

[0097] The plywood 30 further includes a second rectangular piezoelectric layer 90, also analogous to the piezoelectric layer 1 presented above, covering the upper surface of the sealing portion 36 of the frame 30a.

[0098] This second piezoelectric layer 90 can be brought against the upper surface of the reinforcement 30a of the plywood 30 after obtaining the latter, or can be installed beforehand in the mold of the reinforcement 30a which can then be overmolded over the piezoelectric layer 90.

[0099] The stabilizer assembly 10 is then assembled as follows. After manufacturing the flange 20 and the plywood 30, each equipped with its piezoelectric sheet 80, 90, the flange 20 is passed around the stabilizer bar 11. This assembly is then placed in a mold so that the stabilizer bar 11 extends within the flange 20 along the axis B, leaving a continuous and constant clearance between the stabilizer bar 11 and the cradle portion 27 of the flange 20.

[0100] Rubber is then injected into the mold so as to fill the space of the groove 26 left all around the stabilizer bar 11, from the cradle portion 27 of the flange 20 to the opening of the groove 26, thus forming the elastomer layer 19. The elastomer layer 19 thus obtained is then vulcanized so as to secure the stabilizer bar 11 within the flange 20.

[0101] Next, the plywood 30 is placed on the bearing surface 22 of the flange 20. At this time, the protruding parts of the bushings 24 allow the plywood 30 to be positioned and aligned correctly by fitting the bores 34 of the plywood around the bushings 24 of the flange 20.

[0102] Bearing 13 is thus assembled and the same operation can be carried out for the second bearing 13. Alternatively, the two bearings can be assembled simultaneously.

[0103] The stabilizer assembly 10 thus assembled can then be mounted on the chassis of the vehicle by pressing the lower surface 32 of the bearing 13 against the chassis and screwing the bearing 13 onto the chassis with two screws passing through the bores 23 and 34 of the retaining tabs 21 of the flange 20 and the assembly portions 37 of the plywood 30.

[0104] During operation, the bearing 13 is subjected to stress in six directions: three directions of displacement (axial, radial, and normal) and three directions of rotation (torsional, conical around the radial axis, and conical around the normal axis). The position of the piezoelectric plates 80 and 90, at the interface between the stabilizer bar 11 and the bearing 13 reinforcements, allows them to capture a significant portion of the mechanical stresses and vibrations experienced by the bearing 13 and thus produce a substantial amount of electrical energy.

[0105] More particularly, while the main extension direction P of the first piezoelectric layer 80 extends along the retaining lugs and the groove 26, the orientation direction O of the piezoelectric elements forms an angle 0 of 45° with this main direction P because the flange 20 of the bearing 13 undergoes a mixed vibration mode linked to the triaxiality of the stresses (i.e., both along the torsional, conical and radial directions).

[0106] On the other hand, while the main extension direction P of the second piezoelectric layer 90 extends along the main direction of the reinforcement 30a of the plywood 30, the orientation direction O of the piezoelectric elements forms an angle of 0° or 90° with this main direction P because the plywood 30 of the bearing 13 is subjected mainly to a radial vibration mode in bending.

[0107] Figure 6 shows a second example of a vehicle suspension component 110 including a piezoelectric element as described above. It is a leaf spring 110 comprising a metal leaf 111 curved at each end to form an eyelet 115. The leaf spring 110 also includes, for each eyelet 115, a cylindrical bearing 113 inserted into the eyelet 115.

[0108] Figure 7 represents such a bearing 113. The bearing 113 comprises an inner armature 141 and an outer armature 142, both cylindrical and coaxial, between which extends an elastomer layer 143. A first piezoelectric layer 180, analogous to the piezoelectric layer 1 presented above but taking the form of a cylindrical sleeve, is provided between the inner armature 141 and the elastomer layer 143 and a second piezoelectric layer 190, analogous to the piezoelectric layer 1 presented above but also taking the form of a cylindrical sleeve, is provided between the outer armature 142 and the elastomer layer 143.

[0109] In this example, the principal extension direction P of the first piezoelectric layer 180 extends parallel to the central axis of the bearing 113, while its transverse direction T corresponds to the tangential direction of the bearing 113, which closes upon itself. The orientation direction O of its piezoelectric elements forms an angle of 45° with the principal direction P of the piezoelectric layer 180 so as to capture the internal vibrations of the torsional and conical modes.

[0110] The principal extension direction P of the second piezoelectric layer 190 also extends parallel to the central axis of the bearing 113, while its transverse direction T also corresponds to the tangential direction of the bearing 13, which closes upon itself. The orientation direction O of its piezoelectric elements also forms an angle of 45° with the principal direction P of the piezoelectric layer 190 so as to capture external vibrations of the torsional and conical modes; however, preferably, this 45° angle does not have the same sign as for the first piezoelectric layer 180.

[0111] Figure 8 represents a third example of a vehicle suspension component 210 including a piezoelectric element as described above. It is an assembly 210 comprising a helical spring 211 and a support element 213 mounted on a rear suspension cup 216 and against which the helical spring 211 bears.

[0112] Figure 9 shows a cross-section of this support element 213. The upper face of the support element 213 has a groove 251 adapted to receive a portion of the terminal coil 211A of the helical spring 211. In order to receive the portion of the terminal coil 211A, the groove 251 is curved. More precisely, the groove 251 is curved into a helical arc shape corresponding substantially to the helical arc described by the portion of the terminal coil 211A.

[0113] In addition, the support element 213 has at least one elastic retaining member configured to retain the terminal spiral portion 213A in the groove 251. More specifically, the support element 213 has a plurality of elastic retaining members 253 and 255.

[0114] The first elastic retaining organs 253 are reliefs projecting from the radially inner lateral wall 252 of the groove 251. The second elastic retaining members 255 are integral with the radially outer lateral wall 254 of the groove 251.

[0115] In the example shown, the support element 213 comprises a support portion 250 and a base portion 260. The base portion 260 is integral with the support portion 250.

[0116] The support portion 250 has the groove 251 and the elastic retaining organs 253 and 255 already described previously.

[0117] The base portion 260 is suitable for installation on the cup 216. Thus, the base portion 260 has a peripheral portion 265P and a central portion 265C. The central portion 265C has a substantially cylindrical shape allowing it to receive the centering 216C of the cup 216. The support element 213 is thus maintained in contact with the centering 216C.

[0118] The peripheral portion 265P has a substantially flat lower face intended to come into contact with the portion 216P of the cup 214. The upper face of the peripheral portion 265P is intended to come into contact with the lower face of the support portion 250. The upper face of the peripheral portion 265P has a general ring shape, and the lower face of the support portion 250 has a general sector shape. Furthermore, the central portion 265C is received in a central portion 259 of substantially cylindrical shape in the support portion 250.

[0119] A piezoelectric pad 280 analogous to the piezoelectric pad 1 described above is installed between the support portion 250 and the base portion 260. It thus comprises a peripheral portion 280P, having a general ring shape, extending along the peripheral portion 265P of the base portion 260 and a central portion 280C, having a substantially cylindrical shape, extending along the central portion 265C of the base portion 260.

[0120] In this example, the principal extension direction P of the piezoelectric element 280 follows the geometry of the interface between the support portion 250 and the base portion 260: it is therefore locally radial at the peripheral portion 280P and axial at the central portion 280C. The piezoelectric element 280 comprises two sets of piezoelectric elements. The orientation direction O of the piezoelectric elements of the peripheral portion 280P forms an angle of 45° with the principal direction P in order to capture the axial and rotational vibrations of the spring 211 on the peripheral portion 216P of the cup 216.

[0121] On the other hand, the orientation direction O of the piezoelectric elements of the central portion 280C forms an angle of 0° or 90° with the main direction P in order to capture the transverse vibrations of the spring 211 on the centering 216C of the cup 216.

[0122] In a preferred embodiment, the support portion 250 is made of a first material, which is elastic, and the base portion 260 is made of a second material that is more rigid than the first material. Preferably, the first material is an elastomer, more particularly a thermoplastic elastomer, optionally expanded, which may or may not be synthetic, and / or the second material is preferably an organic matrix composite material.

[0123] The bearing portion 250, being made of the first material, tends to absorb noise due to the elasticity of the first material, like the known bearing element mentioned previously. On the other hand, the base portion 260 provides the mechanical connection between the bearing element 213 and the cup 216, and is made of the second material, which is more rigid than the first material and therefore less vulnerable to wear due to contact with the cup 216. As a result, the bearing element 213 has an increased service life, while providing the same noise damping and spring coating protection functions as the known bearing element mentioned previously.

[0124] It should be noted that the support element 213 can be manufactured by two-material injection molding of the first and second materials mentioned above. More specifically, the support element 213 can be manufactured by first injection molding the base portion 260, and then injection molding the support portion 250 onto the base portion 260. These two injection molding steps can be carried out within the same injection mold, by installing the piezoelectric element 280 in the mold between these two molding steps. Alternatively, the injection molding of the base portion 260 can be carried out in a first mold, then the molded base portion 260 can be transferred to a second mold, the piezoelectric element 280 is then installed in this second mold, and finally the injection molding of the support portion 250 is carried out.

[0125] In a particularly preferred example, the support portion 250 is made of expanded thermoplastic polyurethane (“Thermoplastic Polyurethane” or TPU), and / or the base portion 260 is made of glass fiber reinforced polyamide.

[0126] Figure 10 represents a fourth example of a vehicle suspension component 310 including a piezoelectric sheet as described above. It is an assembly 310 comprising a helical spring 311 and a piezoelectric sheet 380 in the form of a sheath threaded around at least a portion of the helical spring 311.

[0127] The piezoelectric sheet 380 is analogous to the piezoelectric sheet 1 presented above, except that its transverse direction T is closed upon itself so as to form a tubular sheath; its principal direction P, for its part, extends in a helix. along the spring 311. The diameter of this sheath formed by the piezoelectric sheet 380 is adjusted to correspond approximately to the diameter of the coils of the spring 311. As is the case in this example, the piezoelectric sheet 380 extends over the entire length of the spring 311. However, in other examples, the piezoelectric sheet could be provided only at one and / or the other end of the spring 311: indeed, the terminal coils of the spring 311 are the coils that accumulate the most mechanical stresses, in particular compressive stress.

[0128] In the present example, the piezoelectric sheet 380 comprises three different portions, each comprising a set of piezoelectric elements configured differently. In the central portion 380C, the orientation direction O forms an angle of 45° with the principal direction P of the sheet 380, and therefore with the helical direction of the spring 311, which makes it possible to capture the torsional deformations stored in the spring wire and the associated vibrations.

[0129] In each end portion 380E, analogous, the orientation direction O forms an angle of 0° or 90° with the main direction P of the sheet 380, which allows it to be more sensitive to the bending forces of the terminal turns and the associated axial vibrations.

[0130] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than a restrictive sense.

[0131] It is also evident that all the characteristics described with reference to a process are transposable, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device are transposable, alone or in combination, to a process.

Claims

Demands

1. Suspension component for a road vehicle, comprising at least one suspension element, having elastic behavior so as to act as a suspension spring during vehicle operation, or at least one interface element (13), configured to participate in the attachment of at least one vehicle suspension element (11) having elastic behavior so as to act as a suspension spring during vehicle operation, and at least one continuous two-dimensional sheet (1, 80, 90), integrated into the suspension element or the interface element (13) or covering at least one interface surface of the suspension element or the interface element, said interface surface being intended to be in contact with another component of the vehicle during vehicle operation, in which said at least one two-dimensional sheet (1, 80,90) comprises a plurality of individual piezoelectric elements (3) arranged in the two-dimensional sheet (1, 80, 90) so as to convert into electricity at least a portion of the vibrations and / or mechanical stresses experienced by the suspension element (11) during vehicle operation, and wherein said at least one two-dimensional sheet (1, 80, 90) further comprises an electrical circuit (4), connecting said individual piezoelectric elements (3) together so as to collect the electricity produced by said piezoelectric elements (3).

2. Suspension member according to claim 1, wherein at least one, and preferably each, two-dimensional sheet (1) has a length of at least 3 cm, preferably at least 5 cm, preferably still at least 10 cm, in a principal extension direction (P), and wherein at least one, and preferably each, two-dimensional sheet (1) has a thickness of less than or equal to 5 mm, preferably less than or equal to 2 mm, preferably still less than or equal to 1 mm.

3. Suspension member according to claim 1 or 2, wherein each individual piezoelectric element (3) has a length less than or equal to 5 mm, preferably less than or equal to 2 mm, of preference still less than or equal to 1 mm.

4. Suspension member according to any one of claims 1 to 3, wherein the two-dimensional web (1) comprises a density of piezoelectric elements (3) greater than or equal to 50 / dm2, preferably greater than or equal to 300 / dm2.

5. Suspension member according to any one of claims 1 to 4, wherein all the individual piezoelectric elements (3) of a two-dimensional sheet (1) are oriented in the same orientation direction (0).

6. Suspension member according to claim 5, wherein said orientation direction (0) is inclined with respect to the principal extension direction (P) of the two-dimensional sheet (101) concerned, and wherein the angle (0) formed between said orientation direction (0) and the principal extension direction (P) of the two-dimensional sheet (101) concerned is between 20 and 70°, preferably between 40 and 50°.

7. Suspension member according to any one of claims 1 to 4, wherein the orientation direction (O) of the individual piezoelectric elements (1) is variable according to their position on the suspension element (11) or the interface element (13).

8. Suspension member according to any one of claims 1 to 7, wherein at least one two-dimensional web (1) comprises a protective layer (7), insulating, covering the individual piezoelectric elements (3) and the electrical circuit (4) of said two-dimensional web (1).

9. Suspension member according to any one of claims 1 to 8, wherein the transverse extension direction (T) of the two-dimensional sheet (380) is closed upon itself, forming a tubular geometry, and wherein the two-dimensional sheet (380) is threaded around the suspension element (311) or the interface element.

10. Suspension member according to any one of claims 1 to 8, wherein the interface element is a bearing (13) configured to be mounted around a stabilizer bar (11) of the vehicle, and wherein said at least one two-dimensional layer (80, 90) is interposed between two components of the bearing (13), preferably between a reinforcement (20a, 30a) and an elastomeric layer (19) in contact with the stabilizer bar (11).

11. Suspension member according to any one of claims 1 to 8, wherein the interface element is a bearing (113) configured to be mounted in an eyelet (115) of a suspension element (111) of the vehicle, and wherein said at least one two-dimensional sheet (180, 190) is interposed between two components of the bearing (113), preferably between a reinforcement (141, 142) and an elastomer layer (143).

12. Suspension member according to any one of claims 1 to 9, wherein the suspension element is a helical spring (311), and wherein said at least one two-dimensional sheet (380) covers at least a portion of the external surface of the helical spring (311).

13. Suspension member according to any one of claims 1 to 8, wherein the interface element is a support element (213) for a helical spring configured to be mounted at one end (21 IA) of a helical spring (211) and to be locked onto a cup (216), and wherein said at least one two-dimensional sheet (280) is interposed between two components of the support element (213), preferably between a support portion (250) in contact with the helical spring (211) and a base portion (260) in contact with the cup (216).

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