Method for adhering a damping device to a suspension element

Abstract

The invention relates to a method for adhering a damping device (20) to a suspension element provided with at least one layer of paint, the damping device (20) being configured to at least partially cover a portion of the suspension element, the method comprising the following successive steps: - a step (E1) of cleaning the surface to be covered; - a step (E2) of applying an adhesion agent to at least part of a rough surface (Z2) of the damping device, which rough surface is intended to at least partially cover said portion; - a step (E3) of aligning the surface of the damping device (20) and the surface of the suspension element so as to bring them into contact; and - a step (E4) of progressively activating microvibrations perpendicular to the rough surface (Z2) to which the adhesion agent has been applied, for a predefined time period, so as to allow bonding to take place under conditions in which the pressure between the two aligned surfaces is evenly distributed.

Description

Description Title of the invention: Method for attaching a damping device to a suspension element Technical Field

[0001] This presentation concerns a damping device and its connection to a suspension element such as a spring or stabilizer bar, a suspension assembly, and a stabilizer assembly.

[0002] Such a stabilizer kit is suitable for any type of stabilizer bar and any type of vehicle, in order to limit vehicle body roll. In particular, such a stabilizer kit can be used on any axle of the vehicle. Previous technique

[0003] The automotive suspension (or stabilizer system) is a complex system that plays a crucial role in managing the interaction between the vehicle and the road surface. Its primary function is to maintain optimal wheel contact with the road, thus ensuring stable handling, increased comfort, and enhanced safety. To achieve these objectives, the suspension must absorb and dissipate shocks and vibrations caused by road irregularities, while allowing the vehicle to remain maneuverable and maintain good traction.

[0004] To this end, suspension elements are integrated into the stabilizer assembly to play a key role in supporting the vehicle's weight and absorbing shocks. Thus, such a suspension element, like a spring (the term "suspension element" may be substituted for "suspension element" and vice versa in the remainder of this patent application), compensates for road variations and maintains a constant ride height despite load changes. The suspension elements act as elastic elements that compress and expand to manage dynamic forces.

[0005] Among the various suspension component configurations, and more specifically springs, available on the market, tubular springs offer unique technical characteristics that can improve the Overall suspension performance. Such a tubular spring is distinguished by its tubular cross-section. This configuration gives the spring a hollow structure with a longitudinal channel that extends the entire length of the suspension element. The main body of the spring is made from an elastic material chosen for its deformation and energy return properties, essential for suspension functions.

[0006] In addition to these various configurations of springs used as suspension elements, there are so-called "solid" or "solid" springs, which are made of a generally homogeneous material (steel or high-strength metal alloy) and have no internal cavity, unlike tubular springs. Their design is based on a compact and robust structure, giving them a high capacity to withstand high loads and significant stresses.

[0007] As an example, such springs 2 and 3, as suspension components, are shown in Figure 1, which illustrates a stabilizer assembly 1 for a vehicle, according to the state of the art. Here, springs 2 and 3 work in conjunction with links 4 and 5. Each link 4 and 5 is attached to a mounting point on a wheel 6 and 7 respectively, typically at a suspension mount. This connection allows the links 4 and 5 to transfer the forces and movements of springs 2 and 3 directly to wheels 6 and 7.

[0008] The two wheels 6 and 7 are generally connected by a stabilizer bar (not visible in Figure 1), also called an anti-roll bar, which joins the two wheels of the same axle. This bar reduces body roll during cornering and dampens suspension deformation, thus maintaining optimal contact between the tires of wheels 6 and 7 and ensuring maximum grip. In other words, each end of the stabilizer bar is attached to the suspension arm of each wheel 6 and 7 via links 4 and 5, while its central section is fixed to the vehicle chassis using at least two bearings.

[0009] However, although suspension components offer several advantages in a stabilizing assembly, the latter remains subject to specific problems that can alter its functions and effectiveness.

[0010] One of the main challenges is stress concentration. The suspension element can contain localized stress zones. In other words, stress concentration refers to the tendency of stresses acting on the suspension element to cluster in specific areas of the spring, creating points of weakness. Consequently, these areas can be subject to uneven wear, increasing the risk of failure. Therefore, a uniform distribution of stress is important to avoid weak points that could lead to premature failure.

[0011] More specifically, the suspension element is subjected to various types of stress, each of which can contribute to stress concentration. Bending stresses develop when the suspension element absorbs loads, particularly during compression or rebound.

[0012] Furthermore, under extreme conditions, particularly very high or low temperatures, the mechanical properties of the suspension component can be affected. For example, at high temperatures, suspension components can soften, lose rigidity, and exhibit a decrease in their damping capacity. For instance, in environments exceeding 80-100°C (such as near an engine or brake subjected to high stress), suspension components can become less resistant to dynamic loads, leading to permanent deformation or a reduction in their effectiveness at dissipating vibration energy. In addition, prolonged exposure to high temperatures can cause chemical degradation, such as oxidation, which weakens the material.

[0013] At low temperatures, suspension components become more rigid and brittle when exposed to temperatures near or below 0°C. This reduces their shock absorption capacity and increases the risk of cracking under sudden loads.

[0014] Furthermore, suspension components are subject to progressive wear under repeated loads (such as driving on rough roads), requiring periodic replacement. Under these high-stress conditions, suspension components can undergo deformation. permanent (creep). The material can then lose its ability to return to its original shape after compression, which reduces its long-term effectiveness.

[0015] Suspension components can also be exposed to chemical or physical agents that alter their structure. For example, oils, fuels, or de-icing agents used on roads can interact with the elastomer, causing a loss of elasticity. Prolonged exposure to water or humid conditions can also promote material degradation. Furthermore, dust, sand, and other abrasive particles present in the environment can accelerate mechanical wear through constant friction. This abrasion can be exacerbated by a mechanism known as sliding / fretting, where repetitive micro-slips between contact surfaces cause localized wear, notably creating noise and discomfort for vehicle passengers.

[0016] Finally, their behavior can be non-linear, making the precise adjustment of certain stabilizer configurations complex.

[0017] To address these issues, damping devices (known as "pads" in the technical jargon understood by those in the business) are often integrated into the stabilizers.

[0018] These damping devices, generally made from elastomeric materials such as rubber or polyurethane, act as intermediaries between the suspension element and other components. Their primary function is to complement the action of the suspension elements by providing additional damping. By acting as a barrier against environmental conditions and minimizing mechanical friction, damping devices are designed to protect the suspension components.

[0019] In other words, damping devices protect suspension components from these aggressions, just as they act as a shock-absorbing cushion, reducing friction and distributing forces, thus preventing premature wear of contact surfaces.

[0020] For the damping device to perform its functions, the connection between the suspension element and the damping device plays a crucial role in the performance and durability of both components. Indeed, an effective and durable connection ensures that the damping device correctly fulfills its protective and damping functions. A solid connection between the suspension element and the damping device allows for a homogeneous distribution of loads across the entire interface surface. This is important for minimizing stress concentration points and ensuring optimal mechanical performance: a suspension element protected by a well-fixed damping device retains its elastic properties over a prolonged period because it is less susceptible to permanent deformations due to unevenly distributed loads.

[0021] If the connection is weak or deteriorating, the damping device could detach or slip, leaving the suspension element exposed to severe conditions, leading to its rapid degradation. Furthermore, a weak connection can cause unwanted movement of the damping device, exposing its edges to accelerated mechanical wear or permanent deformation, and can cause internal shearing within the damping device material if it momentarily slips relative to the suspension element under dynamic loads, potentially resulting in failure.

[0022] In the prior art, several solutions have been proposed to improve adhesion and thus contact between the suspension element and the damping device in vehicle stabilization systems. For example, some solutions combine chemical bonding with mechanical fasteners (e.g., clips, inserts, or pins with or without shims) to reinforce and enhance the connection between the suspension element and the damping device. However, the addition of mechanical fasteners increases the number of components and the complexity of the system, and can introduce unwanted movement between the damping device and the suspension element, especially in environments with high vibration or significant temperature variations.

[0023] Other solutions propose a method of applying spot adhesive to predetermined bonding areas. Specifically, the adhesive is deposited as small dots or segments strategically distributed across the surface of the damping device. However, these localized adhesive application points concentrate the bond between the suspension element and the damping device on a limited area, leaving unbonded zones between them. These zones can become weak points where the damping device is susceptible to slippage or detachment under the effects of vibration or dynamic loads. Because the bonding areas are limited, mechanical stresses are not distributed evenly, which can lead to premature bond failure.

[0024] There is therefore a real need for a more efficient and durable linking solution between the damping device and the suspension element, which is free, at least in part, from the disadvantages inherent in the aforementioned known configurations. Description of the invention

[0025] This presentation relates to a method for bonding a damping device to a suspension element, having at least one layer of paint, the damping device being configured to cover at least partially a portion of the suspension element, the method comprising the following successive steps: - a step of cleaning the surface to be covered; - a step of applying an adhesion agent at least partially to a rough surface of the damping device, intended to cover at least partially said portion; - a step of aligning the surface of the damping device and the surface of the suspension element so as to bring them into contact; and - a step of progressive activation of microvibrations perpendicular to said rough surface on which the adhesion agent has been applied, for a predefined duration, so as to allow bonding by pressure distribution between the two aligned surfaces.

[0026] The suspension component here can be a spring or a vehicle stabilizer bar. In the latter case, the damping device is a bearing designed to at least partially cover the stabilizer bar.

[0027] As for the spring, it is generally used in mechanical or vehicle stabilization systems to absorb shocks and vibrations. This suspension component comprises a plurality of coils, that is, successive loops that make up its structure.

[0028] Cleaning the surface to be coated with the damping device removes impurities such as dust or machining residue. This step ensures a clean surface, which is beneficial for optimal adhesion. By removing these impurities, areas of poor adhesion are prevented, thus avoiding premature assembly failures. This cleaning also contributes to a uniform application of the bonding agent in the following step.

[0029] The bonding agent is thus applied at least partially to a rough surface of the damping device, which will then cover at least a portion of said suspension element, in particular a portion of the coil if it is a spring.

[0030] For the sake of completeness, adhesion here refers to the establishment of a bond between the internal, rough surface of the damping device and at least a portion of the suspension element. This bond is primarily mechanical, achieved through the rough structure of the area, and is further enhanced by chemical adhesion through the application of a compatible adhesive or coating (for example, an adhesive tape, which may be pre-glued and therefore ready to use).

[0031] Furthermore, it should be noted that a chemical adhesive agent is a term that refers to any material used to promote adhesion between two surfaces through a chemical reaction. It can therefore include adhesives less than 30 microns thick, such as epoxy, or adhesives that are activated by heat or cold, or whether they are activated by heat or cold.

[0032] When glue or other adhesives are applied, the surface irregularities allow the chemical agent to penetrate the grooves, forming solid bonds once cured. Thus, the roughness of this area This significantly increases the surface area available for a chemical agent, compared to a smooth surface. The adhesive can then spread over a larger area, increasing the overall bond strength.

[0033] In other words, surface roughness increases the effective contact area between the elements and improves the mechanical retention of the adhesive, resulting in greater resistance to shear forces and mechanical stresses during use. Furthermore, the localized application of the bonding agent optimizes distribution, thus reducing the risk of non-adherent areas.

[0034] The surfaces of the suspension element and the damping device are then aligned to ensure uniform contact and guarantee a homogeneous distribution of pressure during the adhesion stage, and thus avoid causing defects such as air bubbles or areas of low adhesion.

[0035] The process continues with the implementation of a step involving the progressive activation of microvibrations, which are small oscillations, either mechanical in nature or based on waves (e.g., acoustic or ultrasonic). These microvibrations, whether mechanical or acoustic, are applied perpendicularly to the rough surface of the damping device, onto which the adhesive has been applied. Their main function is to promote optimal adhesion by ensuring a uniform distribution of the adhesive, particularly in hard-to-reach areas. To this end, these microvibrations first exploit the ability of the macromolecular chains of the adhesive to organize themselves, both in terms of volume and surface area. This ability to organize plays a crucial role in the development of the macroscopic adhesion properties.Finally, microvibrations improve the wettability of the adhesion agent placed in the hollows formed by the roughness of said surface.

[0036] The gradual nature of the microvibrations is advantageous for controlling this process. Initially, the microvibrations have a low amplitude, allowing for the initial dispersion of the adhesive. Gradually, their intensity increases to maximize the spreading of the adhesive within the irregularities of the rough surface. This gradual process thus allows to avoid the negative effects of a sudden and aggressive activation, such as an uncontrolled displacement of the adhesion agent, but also between the elements in contact.

[0037] In addition, progressive microvibrations help to expel air bubbles or pockets formed between the two surfaces, preventing local weaknesses during adhesion.

[0038] According to certain embodiments of the invention, the method further includes a step of progressively stopping the progressive activation of said microvibrations.

[0039] This gradual shutdown phase reduces, or even prevents, disturbances or misalignments when activation ceases. The intensity of the microvibrations (amplitude and / or frequency) is reduced in a controlled manner, rather than being abruptly stopped. Because the vibrations gradually cease, the aligned surfaces in adhesive contact have time to stabilize without risk of misalignment, and the adhesive, if it is a glue, can still be fluid during the final stages and is thus gently immobilized in an optimal configuration. Furthermore, an abrupt interruption of the microvibrations could cause microcracks in the adhesive layer or create areas of partial debonding.

[0040] Depending on the implementation methods, microvibrations are of a mechanical type.

[0041] Mechanical microvibrations are vibrations generated by mechanical tools that cause direct physical oscillations on the surfaces concerned, unlike microvibrations generated by acoustic or ultrasonic waves which transmit energy without direct contact.

[0042] More specifically, mechanical microvibrations are produced by tools or devices capable of generating controlled, low-amplitude oscillations. These tools are generally suitable for working with sensitive materials, such as those coated with paint. Examples of tools familiar to those in the trade include: vibrating platforms (which may be piezoelectric), and electromagnetic actuators that operate using a magnetic field capable of to produce repetitive and constant vibrations, vibrating clamps or portable devices equipped with a vibrating mechanism, or vibratory induction machines.

[0043] In the case of the use of a vibrating platform, controlled by a person in the trade, the suspension element and the damping device are aligned on the vibrating platform, which may be equipped with supports improving the stability of the contact surfaces during the application of vibrations.

[0044] Of course, microvibrations, whether mechanical or based on sound waves, ultrasound, or others, are not mutually exclusive and can be used in combination or alternately to obtain an optimal result and take advantage of the specific benefits of each type of vibration.

[0045] According to some embodiments of the invention, the step of progressive activation of microvibrations is carried out at a temperature between 0° and 100°C, preferably below 70°C.

[0046] This temperature range was determined based on the physical and chemical properties of the materials and the adhesive used. At these temperatures, the adhesive retains adequate flexibility, allowing for better adhesion.

[0047] According to some embodiments of the invention, the adhesion agent is an epoxy polyurethane adhesive, or an acrylic adhesive, or a material comprising at least two of these adhesives.

[0048] Epoxy polyurethane adhesive combines the mechanical and chemical properties of epoxy resins and polyurethane, offering excellent adhesion to a variety of surfaces, including elastic and metallic materials. Acrylic adhesives, on the other hand, are known for their resistance to temperature and humidity variations, as well as their flexibility. They are therefore particularly well-suited for painted surfaces and those subject to vibration.

[0049] Other adhesives are possible and can be chosen by the professional, for example silicones, phenolics, polyesters, vinyls, polyacrylates, polyurethanes, polysiloxanes, polydienes, styrene-butadene, and polyepoxides.

[0050] The bonding agent may comprise at least two of the adhesives mentioned above (e.g., epoxy polyurethane and acrylic). This mixture allows for the combination of the advantages of at least two adhesives, for example, the robustness and chemical resistance of epoxy polyurethane, as well as the flexibility and tolerance to environmental conditions of acrylic.

[0051] It is worth noting that these adhesives are perfectly suited to rough surfaces, promoting mechanical and chemical interaction between the surfaces to be bonded. Furthermore, these adhesives, particularly when heated to a preferred temperature (such as 70°C), achieve an ideal viscosity that allows for uniform distribution under the effect of progressive micro-vibrations.

[0052] According to some embodiments of the invention, the predefined activation time of the microvibrations is less than 2 minutes, preferably less than 5 seconds.

[0053] The process can include a predefined duration for the generation of microvibrations. This duration is sufficient for the adhesion agent to penetrate the asperities of the rough surface and establish strong chemical and physical bonds, which directly reduces the costs associated with the energy consumption of the equipment and thus contributes to the reduction of CO2 emissions.

[0054] As an example, when an epoxy-polyurethane adhesive is applied at 70°C for 2 minutes: during the first minute, the adhesive molecules begin to penetrate the asperities, while vibrations prevent the formation of bubbles, and by the end of the second minute, the chemical polymerization reactions are well underway, strengthening the chemical bonds so that the chemical bonds reach their maximum effectiveness, ensuring a strong and uniform adhesion.

[0055] According to certain embodiments of the invention, the activation of microvibrations is achieved by a brush applying oscillating friction to the rough surface to which the adhesion agent has been applied, or is achieved by a vibrating device, such as a conveying device, on which the two aligned surfaces are placed.

[0056] As mentioned above, the tools used are designed to apply low-amplitude vibrations in a controlled and progressive manner to the surfaces to be bonded. Among these tools is a brush equipped with vibrating mechanisms used to generate oscillating friction on the rough surface to which the adhesive has been applied. More specifically, the brush's movements cause small oscillations that facilitate the penetration of the adhesive into the surface irregularities and improve the homogeneity of the adhesive layer. By generating friction, the brush promotes interaction between the surfaces without generating excessive heat or damaging the material. Furthermore, the brush can be adjusted to vary the intensity of the friction in order to modulate the activation of the microvibrations.

[0057] Another example of a tool mentioned earlier and familiar to those in the trade involves using a vibrating device, such as a vibrating conveyor, on which two aligned surfaces are placed. The vibrating conveyor typically consists of a platform or belt supported by elements powered by motors or actuators that induce vibrations.

[0058] According to some embodiments of the invention, the microvibrations have a predetermined frequency between 0.1 kHz and 10 kHz, preferably a predetermined frequency between 0.2 kHz and 0.8 kHz and have a predetermined amplitude between 0.1 pm and 1 mm, preferably between 30 pm and 100 pm, during the activation stage, the frequency of the microvibrations being modulated by frequency sweep over this range of predetermined frequencies.

[0059] The predetermined frequency range is advantageous for reducing or even eliminating unwanted mechanical disturbances while allowing efficient penetration of the adhesive agent into surface irregularities.

[0060] The frequency of the microvibrations is modulated here by a frequency sweep over this predetermined range, which means that the intensity and frequency vary This frequency scanning is performed progressively during activation, allowing the system to scan a range of frequencies in order to exploit, at any given moment in the adhesion process, those frequencies that maximize the interaction between the adhesive and the surfaces involved. Furthermore, this frequency scanning minimizes the risk of losing control of the adhesion process.

[0061] As for the predetermined amplitude range, it is chosen to provide a movement subtle enough to create micro-oscillations that promote adhesion.

[0062] The present exposition further relates to a damping device intended for a suspension element having at least one layer of paint, the device being configured to cover at least partially said suspension element, the damping device being characterized in that its internal surface comprises an area which is in direct contact with at least a portion of said suspension element and which has a rough texture.

[0063] The distinctive feature of the damping device lies in a zone on its internal surface, representing the face of the device that faces the suspension element and makes direct contact with it. This zone is characterized by a rough texture specifically designed to make direct contact with at least a portion of the suspension element. "Direct contact" refers to an immediate physical interaction between the rough surface of the damping device and the surface of the relevant suspension element, without the interposition of any additional mechanical elements (an adhesive may then serve as an intermediate layer between the two).

[0064] The rough texture of this direct contact area is an advantageous characteristic. A surface with a rough structure improves the bond between the damping device and the suspension element by enhancing their mechanical adhesion and increasing the effective contact area. This roughness generates physical micro-anchors between the two components, which act as fixing points, preventing any relative movement.

[0065] Unlike purely chemical bonds, which are sensitive to these factors, mechanical micro-anchors ensure long-lasting stability. Furthermore, this configuration minimizes relative movement between surfaces, guaranteeing a strong hold even in the presence of intense vibrations or significant dynamic loads.

[0066] According to one embodiment of the invention, the suspension element being made of elastic material and having a plurality of coils, such as a spring, the device is configured to cover at least partially at least one of said coils, the area being in direct contact with at least a portion of said at least one of the coils.

[0067] In other words, in this embodiment it is a damping device suitable for use in association with a suspension element made of an elastic material such as a spring.

[0068] In the remainder of this patent application, and unless otherwise indicated or the context is inconsistent, the expression "at least a portion of said at least one of the turns," in the context of the use of said damping device, shall be understood as including the following concepts: "a turn," "a plurality of turns," or "one or more portions of several turns," or "one or more portions of a single turn." Thus, each of the aforementioned terms may be substituted by any of the other aforementioned terms.

[0069] As mentioned above, the damping device is configured to at least partially cover one or more coils of this suspension element. This feature means that the damping device wraps around or covers a section of the outer surface of one or more loops of the suspension element, without necessarily covering the entire surface. This partial coverage provides targeted protection and improves the performance of the suspension element under specific conditions, such as reducing friction noise or absorbing vibrations.

[0070] More specifically, it is advantageous to at least partially cover at least one of the turns that is intended to be subjected to: to friction where the coefficient of friction exceeds a predetermined threshold value; and / or - to greater friction than that exerted on the other turns of the suspension element; and / or - to contact pressures or bending stresses greater than those supported by the other turns of the suspension element; and / or - to fatigue phenomena induced by repeated axial displacements; and / or - to a circular or radial slide.

[0071] Initially, the roughened area is designed to cover the coils or portions of coils exposed to significant frictional forces, where the coefficient of friction between the suspension element and its environment exceeds a predetermined value. This can occur in situations where the coils rub against other mechanical components, or when the environment contains abrasive particles or contaminants that increase friction.

[0072] Secondly, it should be noted that certain sections of the coils, or individual coils, depending on their position within the suspension element, experience disproportionate friction compared to other coils. This friction can result from variations in load distribution that increase local pressure.

[0073] Some turns (or parts of turns) are subjected to higher contact pressures or bending stresses than others due to their role in distributing dynamic loads. The roughened area helps to better distribute these localized loads.

[0074] Certain turns or parts of turns are often subjected to repetitive axial movements, that is, continuous cycles of compression or relaxation along their longitudinal axis. These cycles cause mechanical fatigue that can lead to microscopic cracks in the material and / or progressive failure of the affected turn. By covering the areas When stressed, the rough area helps to limit, or even eliminate, the effects of this fatigue.

[0075] Finally, in some cases, certain turns (or parts of turns) may be subject to circular (around the axis of the turns) or radial (perpendicular to this axis) sliding movements, caused by lateral forces that generate a shift in the position of the turns or result from interactions with adjacent surfaces in relative motion. The roughness of the direct contact area then increases mechanical friction in these directions, thus limiting unwanted movements.

[0076] The said zone can thus be configured to at least partially cover at least one of the turns which forms one of the ends of the suspension element or to at least partially cover the body of the suspension element.

[0077] Indeed, the ends of the suspension element are often particularly critical areas because they are generally in direct contact with supports or anchor points of the suspension element, which increases localized mechanical stresses, primarily of the bending or hydrostatic pressure type. Furthermore, during use, the ends can rub against fixed or moving surfaces, generating increased wear. Thus, by covering these coils with a roughened area, the damping device acts as a protective barrier that improves the distribution of mechanical stresses and preserves the structural integrity of the anchor points.

[0078] The body of the suspension element refers to the intermediate coils located between the two ends. These coils also play a central role in the bending and shock-absorbing function of the suspension element. They are also subjected to specific stresses, including repeated bending and torsional stresses, variable dynamic loads, and relative motion vibrations. By covering at least a portion of the main body with a rough area (this configuration being referred to as a "buffer"), i.e., the areas likely to be subjected to these stresses, the damping device increases the mechanical adhesion between the suspension element and itself, reducing slippage or relative displacements, further protects these surfaces against wear due to external friction or abrasion or inter-spiral contact (i.e. one spiral against another in the body of the suspension element), and minimizes fatigue phenomena induced by cyclic stresses.

[0079] In other words, it is advantageous to target critical areas of the suspension element that are subjected to particularly intense mechanical stresses.

[0080] Such a spring-like damping device can be ovoid, circular, rectangular, square, or conical. For the sake of completeness, the shape of the damping device refers to the shape of its surface that will be in contact with the suspension element in order to protect it. Various geometries can be chosen from those known to a person skilled in the art, depending, for example, on the shape of the suspension element itself.

[0081] It should also be noted that the damping device can be advantageously adhered to the suspension element by implementing the adhesion process as defined above.

[0082] According to certain embodiments of the invention, said rough surface has raised patterns in the form of undulations and which have one of the following configurations: - undulations whose amplitude gradually increases from the center of said zone; or - undulations whose amplitude gradually decreases from the center of said zone; or - undulations exhibiting a constant amplitude over the entire area.

[0083] The design of these raised undulations is based on the amplitude, defined as the distance between the highest and lowest points of each undulation. The amplitude can vary according to several configurations.

[0084] According to one configuration, the undulations are weak in the center of the area and become progressively more pronounced towards the edges. Conversely, in the first configuration, the undulations can The ripples may have a maximum amplitude at the center of the area, gradually decreasing towards the edges. Finally, the ripples may be uniform, with an identical amplitude across the entire surface of the rough area.

[0085] The amplitude parameter allows the technician to optimize the management of mechanical stresses applied to the suspension element, particularly on its critical sections, as this reduces the risk of excessive stress concentrations. Indeed, the undulation creates a controlled discontinuity in the contact so that pressures are distributed more evenly, thus reducing areas of potential deformation or failure.

[0086] Of course, other forms of rough surface are possible. For example, said area may contain a plurality of cavities, preferably in the form of pits and / or longitudinal bands, and / or may contain raised longitudinal bands, preferably parallel or wavy.

[0087] The cavities here are depressions integrated into the rough zone; the pits, for example, represent point cavities, circular or otherwise shaped, while the longitudinal bands are cavities extending lengthwise. Such longitudinal bands can be raised and arranged parallel, that is, bands aligned side by side without crossing or significant deviation, or they can be raised and undulating, that is, alternating regular or irregular variations in curvature along the longitudinal direction.

[0088] The present presentation also relates to a suspension assembly, comprising a suspension element having at least one layer of paint, the suspension assembly comprising a damping device as defined above, the area of ​​the internal surface of which is in direct contact with at least a portion of the suspension element so as to conform to the shape of said portion by the implementation of an adhesion process as defined above, said area of ​​the internal surface having a rough texture.

[0089] This presentation also concerns a vehicle stabilizer assembly, comprising at least two suspension assemblies as defined above, and including a stabilizer bar, connecting said at least two suspension assemblies.

[0090] This presentation also relates to a vehicle comprising a stabilizer assembly as defined above.

[0091] The aforementioned features and advantages, as well as others, will become apparent upon reading the detailed description that follows, along with examples of vehicle stabilizer bar bearing designs, and the proposed support and stabilizer assembly. This detailed description refers to the attached drawings. Brief description of the drawings

[0092] The attached drawings are schematic and primarily intended to illustrate the principles of the presentation. In these drawings, identical elements (or parts of elements) are identified by the same reference symbols from one figure to another. [Fig. 1] Figure 1 is a perspective view of a stabilizing assembly comprising two suspension elements according to the state of the art; [Fig. 2A], [Fig. 2C] Figures 2A, 2C are each a perspective view of a suspension element covered at least partially by a damping device according to the state of the art; [Fig. 2B] Figure 2B is a cross-sectional view, along a longitudinal plane, of one end of the suspension element according to the state of the art; [Fig. 3A], [Fig. 3B], [Fig. 3C], [Fig. 3D] Figures 3A, 3B, 3C and 3D each illustrate a perspective view of an area of ​​the internal surface of the damping device, the area being intended to be in direct contact with at least a portion of the suspension element, according to embodiments of the invention; [Fig. 4A], [Fig. 4B] Figures 4A and 4B illustrate different configurations of said zone according to embodiments of the invention; [Fig. 5] Figure 5 illustrates a flowchart of a method of adhesion of the damping device with the suspension element; [Fig. 6A], [Fig. 6B], [Fig. 6C] Figures 6A, 6B and 6C each illustrate different methods of implementing an adhesion agent in said area of ​​the internal surface of the damping device; and [Fig. 7] Figure 7 illustrates a perspective view of a landing according to one embodiment of the invention. Description of the implementation methods

[0093] It is recalled that a suspension element, such as a spring 2 illustrated in Figure 1, comprises a plurality of turns forming a main body 10 disposed between two ends 10a and 10b, visible in Figure 2A.

[0094] The suspension element 2 is here provided with at least one layer of paint and is made of an elastic material which may be, for example, a composite material, or steel, or a steel-based alloy. More generally, the elastic material has a hardness greater than 200 HV (Vickers), preferably greater than 450 HV.

[0095] It should be noted that the external cross-section of the main body 10 and / or its ends 10a and 10b can be, without limitation, circular, ovoid, rectangular, square, or conical in shape. Of course, the term "external" here refers to the shape of the outer contour of the suspension element 2.

[0096] Alternatively, the outer cross-section of the main body 10 and / or its ends 10a and 10b may have a so-called "ground" shape, meaning that the suspension element 2 has undergone a grinding process intended to refine the surface, at least partially, of one or more coils of the suspension element 2. In other words, the surface is smoothed or shaped to achieve the desired dimensions and texture. Furthermore, grinding reduces the overall weight of the component by removing excess material, thus contributing to a lighter assembly, which is particularly advantageous in certain applications, including valve springs. Moreover, in specific applications, notably for vehicle suspension springs, grinding can be used to reduce the overall spring height, which is advantageous when the vehicle body geometry cannot be altered.

[0097] However, some coil sections are exposed to significant frictional forces and contact pressures that can reach approximately 5 MPa, noting that this value depends on the hardness and stiffness of the suspension element and the applied dynamic loads. This can occur in situations where the coils (or sections of coils) rub against other mechanical components, or when the environment contains abrasive particles or contaminants that increase friction. Similarly, some coil sections, or entire coils, depending on their position within the suspension element, experience disproportionate friction compared to other coils. This friction can result from variations in load distribution that increase local pressure.

[0098] Furthermore, some turns (or parts of turns) are subjected to higher contact pressures or bending and torsional stresses than others due to their role in distributing dynamic loads. In addition, some turns or parts of turns are often subjected to repetitive axial movements, i.e., continuous cycles of compression or relaxation along their longitudinal axis. These cycles cause mechanical fatigue that can lead to microscopic cracks in the material and / or progressive failure of the affected turn.

[0099] Finally, in some cases, certain turns (or part(s) of turns) may be subjected to circular or radial sliding movements, caused by lateral forces that generate a shift in the position of the turns or caused by interactions with adjacent surfaces in relative motion.

[0100] To address these issues, it is common practice to use a damping device 20 (referred to as a "pad" in technical jargon). These damping devices 20 are generally made from elastomeric materials such as rubber or polyurethane, and act as an intermediary between the suspension element 2, 3 and the other components. Their primary function is to complement the action of the suspension elements 2, 3 by providing additional damping.

[0101] The damping device 20 may include an insert, not visible in the figures, which acts as a reinforcement and is often made of a plastic composite material such as polyamide. The insert thus improves the structural rigidity of the damping device and allows for better distribution of mechanical loads. The insert may also be at least partially covered with a layer of rubber to improve the absorption of vibrations and shocks thanks to its damping properties.

[0102] Furthermore, such a damping device 20 is designed to conform to the shape of the surface it protects, whether it be a portion of a single turn, a single turn, several turns, several portions of a single turn, or several portions of several turns. In the example shown in Figure 2A, the damping device 20 is positioned to partially enclose the end 10a of the suspension element 2. It therefore partially protects the turn located at this end 10a.

[0103] More specifically, as shown in Figure 2B, which presents a cross-sectional view of end 10a of the suspension element 2, along plane P1 of Figure 2A, the damping device 20 includes a zone Z1 on its internal surface that is in direct contact with said portion. Since the outer section of end 10a is circular, zone Z1 is also circular.

[0104] Of course, the internal surface of the damping device, and more particularly its Z1 zone, can have different shapes, for example an ovoid, rectangular, square, or conical shape, for example.

[0105] As shown in Figure 2B, zone Z1 is adhered to the portion of the spiral at end 10a, creating a chemical bond 30 through the application of an adhesive agent (e.g., glue) or a compatible coating (e.g., an adhesive tape, which may be pre-glued and therefore ready for use). Among the possible adhesive tapes known to those skilled in the art, one can mention the so-called "double-sided" tape, that is, a tape with adhesive surfaces on both sides. Such an adhesive tape may also have, but is not limited to, a thickness of between 1 and 2 millimeters and be applied to the ends of the suspension element.

[0106] Similarly, as illustrated in Figure 2C, zone Z1 is bonded between two portions of turns or at strategic points along the suspension element. This configuration is known by the English term "buffer".

[0107] The chemical bond 30 is not sufficient in itself to guarantee an effective and durable fixing between the suspension element 2 and the damping device 20. Indeed, under these conditions, the damping device 20 could detach or slip, leaving the suspension element 2 exposed to severe conditions, which will lead to its rapid degradation.

[0108] Moreover, such a chemical bond 30 can further cause parasitic movements of the damping device 20, exposing its edges to accelerated mechanical wear or permanent deformations, and can cause internal shearing in the material of the damping device 20 if it momentarily slips relative to the suspension element 2 under dynamic loads, which could lead to breakage.

[0109] Thus, the invention proposes a more efficient and more durable connection solution between the damping device 20 and the suspension element 2, which is free, at least in part, from the disadvantages inherent in known attempts to create such a connection.

[0110] To this end, it is proposed firstly that zone Z1 have a rough texture 31 which improves the connection between the damping device 20 and the suspension element 2 (or 3) by strengthening their mechanical adhesion and increasing the effective contact area. As explained above, this roughness 31 generates physical micro-anchors between the two components, which act as fixing points preventing any relative movement.

[0111] Indeed, these micro-anchors are particularly effective at maintaining a functional bond when exposed to corrosive chemicals, or in the presence of pollutants that may include abrasive particles such as Arizona sand or basaltic gravel, which can infiltrate the interfaces. Thus, unlike purely chemical bonds 30, which are sensitive to these factors, mechanical micro-anchors 31 ensure more durable stability.

[0112] Naturally, this bond 31, facilitated by the roughness of zone Z1, primarily creates a mechanical adhesion. This is then complemented by a chemical adhesion 30, for example, through the application of an adhesive. More precisely, when an adhesive is applied, the asperities of zone Z1 allow the adhesive to penetrate the grooves of the roughness 31, forming solid anchor points once cured. Thus, the roughness 31 of this zone Z1 significantly increases the surface area available for an adhesive, compared to a smooth surface. The adhesive can then spread over a larger area, increasing the overall bond strength.

[0113] The rough Z1 zone can have several configurations. As an example, Figure 3A illustrates one configuration of the Z1 zone, which here features a plurality of undulating relief patterns. A second configuration of the Z1 zone is illustrated in Figure 3B, in which a plurality of pit-like cavities can be seen. Such cavities can also take the form of longitudinal bands, as illustrated in Figure 3C.

[0114] Other configurations of the rough zone Z1 are possible. For example, zone Z1 may have raised longitudinal bands, as illustrated in Figure 3D and referenced as 36. These longitudinal bands are shown here as wavy but may also be alternately or additionally parallel. Similarly, as can be seen in this Figure 3D, the bands may also be transverse and wavy, but also parallel.

[0115] Zone Z1 can have several possible forms, which may follow one another among the aforementioned forms. Thus, this does not preclude the possibility that the rough zone Z1 may contain excavated pits followed by a series of longitudinal raised bands, for example.

[0116] Figure 4A illustrates three particular configurations V1, V2 and V3 of the rough zone Z1, along the plane P1, when the latter presents undulations in relief.

[0117] More specifically, in configuration V1, the amplitude of the undulations increases progressively from the center 40 of said zone Z1, whereas in configuration V2, the amplitude of the undulations decreases progressively from the center 40 of said zone Z1. Finally, lastly As an alternative to the V3 configuration, the undulations can exhibit a constant amplitude over the entire area Z1.

[0118] Of course, the undulations of the rough zone Z1 may very well exhibit at least two of the configurations V1, V2 and V3. For example, the undulations may increase gradually from the center 40, then decrease gradually and finally be of constant amplitude at the edges.

[0119] As mentioned above, the amplitude parameter allows the person in the trade to perform optimized management of the mechanical stresses applied to the suspension element, and particularly on its critical portions, as this reduces the risks of excessive stress concentrations.

[0120] Indeed, the undulation creates a controlled discontinuity in the contact so that pressures are distributed more evenly, thus reducing areas of potential deformation or failure. This controlled discontinuity aims to allow a smooth transition between peaks, minimizing stress concentrations and promoting better load distribution.

[0121] For example, the peak positive amplitude in the V1 configuration can be between 10 pm and 5 mm, just as the maximum negative amplitude in the V1 configuration can be between 5 mm and 10 pm. Finally, in the V3 configuration, the constant amplitude can also be between 10 pm and 5 mm, for example.

[0122] Such undulations can be formed using various technical processes tailored to manufacturing requirements. For example, undulations can be generated by molding, where a pre-formed die directly creates the undulating texture on the surface during the molding process. Another method involves using 3D printing, which allows for the fabrication of undulating structures with high precision. Finally, undulations can be created by laser engraving, a process that involves directly engraving a undulating structure onto the Z1 zone by removing material in a controlled manner.

[0123] It should be noted that once the damping device 20 is positioned around the area to be covered, its roughness in zone Z1 allows it to act like a suction cup, thus creating effective adhesion between the area of The suspension element to be covered and the damping device 20. More specifically, this roughness allows the use of the differential pressure principle to create an adhesive force without requiring mechanical fastening. Thus, when pressure is exerted on area Z1, the roughness generates compression that modifies the shape of the surface of the damping device 20, as can be seen in Figure 4B. The arrows 80 on either side of the portion of the suspension element 2 then symbolize and indicate the direction in which the damping device 20 reacts once the portion is placed in the damping device 20, in other words, once the pressure is applied.

[0124] This then provides additional sealing protection against intrusions, preventing small debris, such as dust, sand or other contaminants, from entering the junction between the portion of the suspension element to be covered and the Z1 zone of the damping device 20.

[0125] However, mechanical adhesion alone has certain limitations. It can be affected by external stresses such as shear or peeling, which tend to separate materials when physical anchoring is insufficient. Furthermore, in environments exposed to temperature variations or humidity, mechanical adhesion can deteriorate due to differential expansion or the degradation of anchor points.

[0126] Therefore, chemical adhesion must be combined with mechanical adhesion to optimize the bond between materials. Chemical adhesion relies on the formation of chemical bonds between the functional groups of the surfaces in contact. These interactions at the molecular level allow for a more intimate and resistant bond. By combining these two mechanisms, it is possible to achieve enhanced and durable adhesion.

[0127] In order to benefit from the combined advantages of mechanical and chemical adhesion, a method of adhesion of the damping device 20 with the suspension element 2 is proposed, as described in Figure 5. Tl

[0128] More specifically, the process begins with a step E1 of cleaning the surface to be coated, i.e., the surface of the damping device 20 and the suspension element 2 that are in contact, in order to reduce or even eliminate impurities such as dust or machining residues. As mentioned above, this step E1 results in a clean surface, which is advantageous for optimal adhesion. This cleaning also contributes to a uniform application of the bonding agent in the following step E2.

[0129] The process therefore continues with a step E2 of applying an adhesion agent at least partially to the rough surface of the damping device 20, intended to cover at least partially a portion of the suspension element, in particular at least one of said coils of the suspension element when it is a spring.

[0130] More specifically, there are different ways to implement the bonding agent, at least partially, in the rough zone Z1. In a first example illustrated in Figure 6A, which shows the V1 configuration, the bonding agent, symbolized by circles inside the cavities of zone Z1, is applied only at the ends of the rough zone Z1. The area in which the bonding agent is applied is then referred to as Z2 in the figure.

[0131] In a second example of the implementation of the adhesion agent at least partially in the rough zone Z1, Figure 6B illustrates the V2 configuration of the zone Z1, in which the adhesion agent was applied only at the center 40 of said zone Z1.

[0132] In a third example of the implementation of the adhesion agent at least partially in the rough zone Z1, Figure 6C illustrates the V3 configuration of the zone Z1, in which the adhesion agent has been applied over the entire surface of the zone Z1.

[0133] The localized application of the adhesion agent then optimizes the distribution, thus reducing the risk of non-adherent areas.

[0134] The process continues with step E3, which aligns the surface of the damping device 20 and the surface of the suspension element 2 so as to bring them into contact. This ensures uniform contact and ensure a homogeneous distribution of pressure during adhesion, which avoids causing defects such as air bubbles or areas of low adhesion.

[0135] Finally, the process concludes with the implementation of step E4, which involves the progressive activation of microvibrations. These microvibrations are small oscillations, preferably mechanical in nature, for example, or based on waves (acoustic or ultrasonic, for example). Such microvibrations, whether mechanical or acoustic, are applied perpendicularly to the rough surface of the damping device 20, to which the adhesive has been applied.

[0136] For this purpose, microvibration is activated by a brush, referenced as 60, for a duration of less than 2 minutes, for example, and preferably less than 5 seconds. Brush 60 is intended to apply oscillating friction to the rough surface Z2, onto which the bonding agent has been applied. Of course, a person skilled in the art may choose other means of activating these microvibrations, for example, by a suitable vibrating device such as a conveyor on which the two aligned surfaces can be placed. Other examples of such methods of implementing microvibrations are also mentioned above.

[0137] Step E4, the progressive activation of microvibrations, can advantageously, but not limited to, be implemented at a temperature between 0° and 100°C, preferably below 70°C. A person skilled in the art is obviously able to select a suitable temperature, whether within this range or based on the physical and chemical properties of the materials and the adhesive used (e.g., epoxy polyurethane adhesive, acrylic adhesive, or a material containing at least two of these adhesives).

[0138] Furthermore, other parameters can also be modulated by the person in the trade to implement the activation of microvibrations in step E4. For example, it is possible to modulate the frequency of the microvibrations and / or their amplitude and / or to implement a frequency sweep over a predetermined frequency range.

[0139] As an example, a person in the trade may choose a predetermined frequency between 0.1 kHz and 10 kHz, preferably a predetermined frequency between 0.2 kHz and 0.8 kHz, and may choose a predetermined amplitude between 0.1 pm and 1 mm, preferably between 30 pm and 100 pm.

[0140] By activating these micro-vibrations, the adhesion agent is then better distributed, particularly in hard-to-reach areas, while also improving its wettability.

[0141] It should be noted that the activation of these microvibrations is gradual for several reasons. Among them, it helps to expel air bubbles or pockets formed between the two surfaces, but also to avoid the negative effects of a sudden and aggressive activation.

[0142] The process may include an optional additional step E5 for the gradual cessation of the progressive activation of said microvibrations. As explained above, step E5 is advantageous because it reduces, or even prevents, disturbances or misalignments at the point when the activation ceases. Furthermore, an abrupt interruption of the microvibrations could cause microcracks in the adhesive layer or create areas of partial debonding.

[0143] 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, the adhesion method can be applied to a damping device 20 in the form of a bearing, as illustrated in Figure 5, which at least partially covers a stabilizer bar 90 for a vehicle. It should be noted that a bearing, a device known to those skilled in the art, serves to secure the stabilizer bar to the vehicle chassis while providing a degree of damping.

[0144] Thus, the internal surface of the bearing also includes a Z1 zone which is in direct contact with at least a portion of the stabilizer bar, the zone Z1 exhibiting a rough texture as described above with its various embodiments.

[0145] Furthermore, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered illustrative rather than restrictive.

[0146] 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. A method for bonding a damping device (20) to a suspension element having at least one layer of paint, the damping device (20) being configured to at least partially cover a portion of the suspension element, the method comprising the following successive steps: - a step (E1) of cleaning the surface to be covered; - a step (E2) of applying an adhesion agent at least partially to a rough surface (Z2) of the damping device (20), intended to cover at least partially said portion; - a step (E3) of aligning the surface of the damping device (20) and the surface of the suspension element so as to bring them into contact; and - a step (E4) of progressive activation of microvibrations perpendicular to said rough surface (Z2) on which the adhesion agent has been applied, for a predefined duration, so as to allow bonding by pressure distribution between the two aligned surfaces.

2. A method according to claim 1, further comprising a step of progressively stopping the progressive activation of said microvibrations.

3. A method according to claim 1 or 2, wherein the microvibrations are of a mechanical type.

4. A method according to any one of the preceding claims, wherein the step of progressive activation of microvibrations is carried out at a temperature between 0° and 100°C, preferably below 70°C.

5. A method according to any one of the preceding claims, wherein the bonding agent is an epoxy adhesive polyurethane, or acrylic, or a material comprising at least two of these adhesives.

6. A method according to any one of the preceding claims, wherein the predefined activation time of the microvibrations is less than 2 minutes, preferably less than 5 seconds.

7. A method according to any one of the preceding claims, wherein the activation of the microvibrations is achieved by a brush (60) applying oscillating friction on the rough surface (Z2) on which the adhesion agent has been applied, or is achieved by a vibrating device, such as a conveying device, on which the two aligned surfaces are arranged.

8. A method according to any one of the preceding claims, wherein the microvibrations have a predetermined frequency between 0.1 kHz and 10 kHz, preferably a predetermined frequency between 0.2 kHz and 0.8 kHz, and have a predetermined amplitude between 0.1 pm and 1 mm, preferably between 30 pm and 100 pm, during the activation step, the frequency of the microvibrations being modulated by frequency sweep over this range of predetermined frequencies.

9. Damping device (20) for a suspension element having at least one coat of paint, the device (20) being configured to at least partially cover said suspension element, the damping device (20) being characterized in that its internal surface comprises an area (Z1) which is in direct contact with at least a portion of said suspension element and which has a rough texture.

10. Damping device (20) according to claim 9, wherein the suspension element being made of elastic material and having a plurality of coils, such as a spring, the device (20) is configured to cover at least partially at least one of said coils, the area (Z1) being in direct contact with at least a portion of said at least one of the coils.

11. Device (20) according to claim 10 or 9, wherein said rough surface (Z1) has raised patterns in the form of undulations and which have one of the following configurations (V1; V2; V3): - undulations whose amplitude gradually increases from the center of said zone (Z1); or - undulations whose amplitude gradually decreases from the center of said zone (Z1); or - undulations exhibiting a constant amplitude over the entire said zone (Z1).

12. Suspension assembly, comprising a suspension element (2; 3) having at least one layer of paint, the suspension assembly comprising a damping device (20) according to any one of claims 9 to 11, the area (Z1) of the internal surface of which is in direct contact with at least a portion of the suspension element (2; 3) so as to conform to the shape of said portion by implementing an adhesion process according to any one of claims 1 to 8, said area (Z1) of the internal surface having a rough texture.

13. Stabilizer assembly for vehicle, comprising at least two suspension assemblies, according to claim 12, and comprising a stabilizer bar connecting said at least two suspension assemblies.

14. Vehicle comprising a stabilizer assembly according to claim 13.

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