Vibration and shock absorption device for equipping a multi-leaf spring with a suspension

Abstract

Vibration and shock absorption device for equipping a multi-leaf spring, comprising: - a first buffer (1), comprising: a first plate (10), a first elastic coating (11), a threaded rod (12); - a second buffer (2), comprising: a second plate, provided with a through-hole arranged to receive the threaded rod (12), a second elastic coating (21), provided with a through-opening (210) arranged to face the through-hole, a nut (3), arranged to cooperate with the threaded rod (12) so as to assemble the second buffer (2) to the first buffer (1) when the through-hole receives the threaded rod (12), the through-opening (210) being sized to receive the threaded rod (12) and the nut (3). Figure 3

Description

Title of the invention: Vibration and shock absorption device for equipping a multi-leaf spring with a suspension Technical field

[0001] The invention relates to the technical field of vibration and shock absorption devices for equipping a multi-leaf spring of a vehicle suspension.

[0002] The invention finds its application in particular in suspensions of the rigid axle type with leaf springs. State of the art

[0003] A vehicle suspension may include: - two leaf springs (also called multi-leaf springs); - two shock absorbers.

[0004] The role of multi-leaf springs is to keep the suspended load of the vehicle flexibly. The role of shock absorbers is to absorb the stored energy, then the energy released, by the multi-leaf springs. Shock absorbers prevent oscillations of the vehicle, for example when the vehicle crosses a speed bump.

[0005] Multi-leaf springs are typically fitted to vehicles that regularly have to transport heavy loads. A multi-leaf spring may include: - an upper blade, called the master blade; - a lower blade; - an intermediate blade, inserted between the upper blade and the lower blade.

[0006] Several blade configurations may exist. A typical configuration is a lower blade of the compensating blade type, and an intermediate blade of the reinforcing blade type. The blades are generally made of steel, providing an optimal combination of strength and flexibility.

[0007] However, a recurring technical problem is the premature wear of the blades, due to friction between the blades and the hardness of the steel, particularly when the vehicle regularly uses roads with significant irregularities or in extreme conditions. Other problems are caused by the friction of the blades, such as noisy squeaking generating noise discomfort, or even accelerated corrosion of the blades.

[0008] For this purpose, it is known from the state of the art to use buffers, generally made of a rubber material, which are interposed between the blades in order to prevent their friction.

[0009] More specifically, there are different types of buffers: (i) so-called simple stamp; (ii) so-called threaded buffer; (iii) sock tampon.

[0010] A simple buffer is a block of rubber (or nylon) material which is simply interposed between two blades. The simple buffer comprises at least one positioning pin (or lug) (also called a centering pin) of rubber material, arranged to cooperate with an orifice of a blade.

[0011] Such a prior art buffer is not entirely satisfactory insofar as it can easily become detached, not being mechanically fixed to a blade.

[0012] A threaded pad is used for bi-leaf springs (one upper leaf and one lower leaf), and generally comprises: - a metal plate, coated with a rubber block, and fitted with a threaded rod; - a nut, arranged to cooperate with the threaded rod so as to assemble the metal plate to the lower blade, the rubber block being oriented towards the upper blade.

[0013] Such a buffer of the state of the art is not entirely satisfactory insofar as it cannot be used with a three-leaf spring. Indeed, the assembly of the metal plate to the intermediate blade by the nut would lead to contact of the end of the threaded rod (and possibly of the nut) with the lower blade.

[0014] A sock pad is a hollow block of rubber material, having a through cavity whose shape coincides with the cross-section of the interposed blade. The sock pad is threaded so as to envelop a portion (at the end or in the center) of the interposed blade. The cavity delimits an upper portion of the block oriented towards the upper blade, and a lower portion of the block oriented towards the lower blade. A sock pad may comprise at least one positioning pin (or lug) (also called a centering pin) of rubber material, arranged to cooperate with an orifice of a blade.

[0015] Such a state-of-the-art buffer is not entirely satisfactory since premature wear of the blades has been observed when the vehicle regularly uses roads with significant irregularities or in extreme conditions (e.g. crossing bridges for an all-terrain vehicle, crossing steps, high-speed paths, etc.). In fact, the sock buffer will slide inexorably from the outside of the intermediate blade towards the center of the intermediate blade (at the axle), leaving the ends of the blades in direct contact. The sock buffer is more stable than a simple buffer due to the friction between the blade in intercalaire and the hollow block made of rubber material, and the geometric conformity between the cavity and the cross-section of the intercalaire blade. However, this stability proves insufficient when the vehicle is used in extreme conditions. Statement of the invention

[0016] The invention aims to remedy all or part of the aforementioned drawbacks. To this end, the invention relates to a vibration and shock absorption device for equipping a multi-leaf spring with a suspension, the device comprising: - a first stamp, comprising: a first plate, having first and second opposing surfaces, a first elastic coating, extending over the first surface, a threaded rod, extending normal to the second surface; - a second buffer, comprising: a second plate, having first and second opposing surfaces, and provided with a through hole arranged to receive the threaded rod, the second surface of the second plate facing the second surface of the first plate, a second elastic coating, extending over the first surface of the second plate, and provided with a through opening arranged to face the through hole, a nut, arranged to cooperate with the threaded rod so as to assemble the second pad to the first pad when the through-hole receives the threaded rod, the through-opening being sized to receive the threaded rod and the nut.

[0017] Thus, such a device according to the invention allows: - to be mechanically fixed to an intermediate blade, unlike a simple buffer of the state of the art, thanks to the cooperation of the nut and the threaded rod guaranteeing good mechanical strength; - to be used with a three-leaf spring, unlike a threaded buffer of the state of the art, thanks to such a second buffer which prevents contact between the end of the threaded rod (and the nut) and the lower blade; - to be mechanically fixed to an interlayer blade, unlike a sock pad of the state of the art, thanks to the cooperation of the nut and the threaded rod guaranteeing good mechanical strength. Indeed, the mechanical fixing (nut, threaded rod) prevents the device from sliding along the interlayer blade.

[0018] The device according to the invention may comprise one or more of the following characteristics.

[0019] According to a characteristic of the invention, the through opening is sized to receive a tightening sleeve for the nut.

[0020] Thus, an advantage provided is to facilitate the installation (i.e. screwing) of the nut. when assembling the device on an intermediate leaf of a multi-leaf spring.

[0021] According to a characteristic of the invention, the device comprises a centering sleeve arranged between the first and second plates to guide the threaded rod inside the centering sleeve.

[0022] Thus, an advantage provided is to obtain excellent compatibility of the device with different types of leaves of a multi-leaf spring. The outside diameter of the centering sleeve can be adapted to the through hole of the intermediate leaf; the inside diameter of the centering sleeve can be adapted to the diameter of the threaded rod. The centering sleeve also makes it possible to ensure precise positioning of the various mechanical parts of the device. Finally, the centering sleeve makes it possible to absorb radial stresses which may be exerted on the threaded rod under rolling conditions, in order to eliminate any excessive load on the threaded rod. A centering sleeve is also called a positioning sleeve.

[0023] According to a characteristic of the invention, the threaded rod extends along a longitudinal axis, the device comprises rotation locking means arranged to lock a rotation of the first and second buffers around the longitudinal axis.

[0024] Thus, an advantage provided is to allow greater freedom in the shape and dimensions of the first and second buffers, without the risk of protruding from the outer surface of the intermediate blade when placed across. In the absence of rotational locking, the first and second buffers generally have a cross-section (relative to the longitudinal axis of the threaded rod) of circular shape, the diameter of which is less than the width of the intermediate blade. Consequently, the presence of such rotational locking means allows the use of first and second buffers with an oblong cross-section, for example rectangular. Such an oblong cross-section makes it possible to increase the useful vibration and shock absorption surface of the device.

[0025] According to a characteristic of the invention, the rotation locking means comprise: - a plate, arranged between the first and second pads, and having first and second opposing surfaces; the first surface of the plate facing the second surface of the first plate; - first projecting elements, extending projecting from the first surface of the plate so as to block a rotation of the first buffer around the longitudinal axis; - second projecting elements, extending projecting from the second surface of the plate so as to block a rotation of the second buffer around the longitudinal axis.

[0026] Thus, an advantage provided by such rotational locking means is the ease of their assembly with the other mechanical parts of the device for a reduced cost.

[0027] According to a characteristic of the invention, the first and second buffers each have a transverse section to the longitudinal axis of rectangular shape.

[0028] Thus, one advantage provided by such an oblong shape is ease of manufacture.

[0029] According to a characteristic of the invention, the threaded rod is a threaded rod of a screw of fixing, the fixing screw being fixed to the first plate.

[0030] Thus, an advantage provided by the fixing screw is the ease of installation on the first plate, the first plate providing a bearing surface for the head of the fixing screw.

[0031] The invention also relates to a multi-leaf spring for equipping a vehicle suspension, comprising: - an upper blade, called the master blade; - a lower blade; - an intermediate blade, inserted between the upper blade and the lower blade, and having first and second opposite end portions provided respectively with first and second through holes; - first and second devices in accordance with the invention; the threaded rods of the first pads of the first and second devices being respectively inserted into the first and second through holes; the first and second pads of the first and second devices being assembled in abutment against the intermediate blade by the nuts of the first and second devices.

[0032] According to a characteristic of the invention: - the first surfaces of the first plates of the first buffers are oriented towards the upper blade; - the threaded rods of the first buffers each have a length; - the second elastic coverings of the second buffers each have a thickness adjusted according to the length of the threaded rods so that the threaded rods are entirely contained inside the through openings, at a distance from the lower blade.

[0033] The second pad generally has a thickness greater than that of the first pad in order to contain the threaded rod inside the through opening, at a distance from the lower blade. In practice, the space between the intermediate blade and the lower blade is generally greater than the space between the intermediate blade and the upper blade (master blade), in particular when the intermediate blade is a reinforcing blade and the lower blade is a compensating blade. Thus, it is advantageous to orient the first pads towards the upper blade, and the second pads towards the lower blade.

[0034] The invention finally relates to a suspension of a vehicle, comprising at least a multi-leaf spring according to the invention.

[0035] Definitions

[0036] - By "buffer" is meant a mechanical component designed to exert a vibration and shock absorption function.

[0037] - By "elastic coating" is meant a coating made from a material elastic. An elastic material, or elastically deformable material, can deform reversibly under the action of mechanical stresses below the elastic limit, that is, the elastic coating can return to its initial shape when the mechanical stresses cease.

[0038] - By "thickness" is meant a dimension along the longitudinal axis of the rod threaded.

[0039] - By "through hole" is meant an hole passing through the second plate of the second buffer in its thickness.

[0040] - By "through opening" is meant an opening passing through the second re elastic garment of the second tampon in its thickness.

[0041] - By "through hole" is meant a hole passing through the end portion of the blade interlayer in its thickness.

[0042] - By "fully contained within the through opening" is meant that the rod threaded rod of the first pad does not protrude beyond the outer surface of the second elastic coating of the second pad. In other words, the threaded rod of the first pad is located below the outer surface of the second elastic coating of the second pad, and therefore at a distance from the lower blade. Brief description of the drawings

[0043] Other features and advantages will become apparent in the detailed description of different embodiments of the invention, the description being accompanied by examples and references to the attached drawings.

[0044] [Fig.l] is a schematic side view, in exploded perspective, of a device according to the invention equipping an intermediate blade with a multi-leaf spring. For the sake of readability, the upper and lower blades are not shown, and only a part (approximately half) of the intermediate blade is shown.

[0045] [Fig.2] is a schematic view similar to [Fig.l], on an enlarged scale.

[0046] [Fig.3] is a schematic view similar to [Fig.2], in a different orientation of the interlayer blade.

[0047] [Fig.4] is a schematic side view, in perspective, of a device according to the invention equipping an intermediate blade with a multi-leaf spring. For the sake of readability, the upper and lower blades are not shown, and only part of the intermediate blade is shown.

[0048] [Fig.5] is a schematic view similar to [Fig.4], according to a different orientation of the intercalary blade.

[0049] It should be noted that the drawings described above are schematic, and are not necessarily to scale for the sake of readability and to simplify their understanding. Detailed description of the embodiments

[0050] Elements that are identical or provide the same function will bear the same references for the different embodiments, for the sake of simplification. Device

[0051] An object of the invention is a vibration and shock absorption device for equipping a multi-leaf spring with a suspension, the device comprising: - a first buffer 1, comprising: a first plate 10, having first and second opposite surfaces (only the second surface 100 is visible), a first elastic coating 11, extending over the first surface, a threaded rod 12, extending normal to the second surface 100; - a second buffer 2, comprising: a second plate 20, having first and second opposite surfaces (only the second surface 200 is visible), and provided with a through-hole 201 arranged to receive the threaded rod 12, the second surface 200 of the second plate 20 facing the second surface 100 of the first plate 10, a second elastic coating 21, extending over the first surface of the second plate 20, and provided with a through opening 210 arranged to face the through hole 201, a nut 3, arranged to cooperate with the threaded rod 12 so as to assemble the second buffer 2 to the first buffer 1 when the through-orifice 201 receives the threaded rod 12, the through-opening 210 being sized to receive the threaded rod 12 and the nut 3.

[0052] First stamp

[0053] The first buffer 1 comprises: - a first plate 10, having first and second opposite surfaces; - a first elastic coating 11, extending over the first surface of the first plate 10; - a threaded rod 12, extending along the normal to the second surface 100 of the first plate 10.

[0054] The first plate 10 is advantageously made of a metallic material, preferably steel, offering an excellent compromise between economic cost and mechanical resistance to friction. However, other materials are conceivable. By way of non-limiting examples, the first plate 10 may be made of a composite material or of an engineering plastic material. The composite material or the engineering plastic material advantageously comprises reinforcing fibers such as glass fibers or carbon fibers. The engineering plastic material may, for example, be based on reinforced polyetheretherketone (PEEK), reinforced polyamide or even reinforced polypropylene. These alternative materials are nevertheless more expensive.

[0055] The first elastic coating 11 is advantageously made of an elastomeric material, preferably of the rubber type. The first elastic coating 11 may be formed on the first plate 10 by an adhesion technique. The adhesion makes it possible in particular to obtain a high adhesion energy between the rubber and the steel. The adhesion of the rubber to the steel is created during the vulcanization phase of the rubber. The first elastic coating 11 advantageously has a hardness of between 50 Shore A and 70 Shore A, preferably of between 55 Shore A and 65 Shore A.

[0056] The threaded rod 12 extends along a longitudinal axis A. The threaded rod 12 is advantageously a threaded rod 12 of a fixing screw. The fixing screw is fixed to the first plate 10, preferably by welding. By way of non-limiting example, the threaded rod 12 may have a diameter of 8 mm.

[0057] The first pad 1 advantageously has a cross-section to the longitudinal axis A that is oblong, preferably rectangular in shape. In particular, the first elastic coating 11 advantageously has a cross-section to the longitudinal axis A that is rectangular in shape. By way of non-limiting example, the first pad 1 may have a useful surface area of between 3800 mm2 and 5000 mm2.

[0058] Second buffer

[0059] The second buffer 2 comprises: - a second plate 20, having first and second opposite surfaces, and provided with a through-hole 201 arranged to receive the threaded rod 12, the second surface 200 of the second plate 20 facing the second surface 100 of the first plate 10, - a second elastic coating 21, extending over the first surface of the second plate 20, and provided with a through opening 210 arranged to face the through orifice 201.

[0060] The second plate 20 is advantageously made of a metallic material, preferably steel, offering an excellent compromise between economic cost and mechanical resistance to friction. However, other materials are conceivable. By way of non-limiting examples, the second plate 20 may be made of a composite material or of a technical plastic material. The composite material or the technical plastic material advantageously includes reinforcing fibers such as glass fibers or carbon fibers. The technical plastic material can be based, for example, on reinforced polyetheretherketone (PEEK), reinforced polyamide or reinforced polypropylene. These alternative materials are, however, more expensive.

[0061] The second elastic coating 21 is advantageously made of an elastomeric material, preferably of the rubber type. The second elastic coating 21 may be formed on the second plate 20 by an adhesion technique. The adhesion makes it possible in particular to obtain a high adhesion energy between the rubber and the steel. The adhesion of the rubber to the steel is created during the vulcanization phase of the rubber. The second elastic coating 21 advantageously has a hardness of between 50 Shore A and 70 Shore A, preferably of between 55 Shore A and 65 Shore A.

[0062] The through opening 210 is sized to receive the threaded rod 12 and the nut 3. The through opening 210 is advantageously sized to receive a tightening sleeve for the nut 3. By way of non-limiting example, the through opening 210 may have a cross-section to the longitudinal axis A of circular shape.

[0063] The second pad 2 advantageously has a cross-section to the longitudinal axis A that is oblong, preferably rectangular in shape. In particular, the second elastic coating 21 advantageously has a cross-section to the longitudinal axis A that is rectangular in shape. By way of non-limiting example, the second pad 2 may have a useful surface area of between 3400 mm2 and 4700 mm2.

[0064] Nut

[0065] The nut 3 is arranged to cooperate with the threaded rod 12 so as to assemble the second buffer 2 to the first buffer 1 when the through-orifice 201 receives the threaded rod 12. The nut 3 therefore has a shape and dimensions adapted to the diameter and the thread of the threaded rod 12. The fixing of the second buffer 2 to the first buffer 1 is carried out by tightening against the intermediate blade 6, by screwing the nut 3 onto the threaded rod 12. The tightening of the nut 3 can be carried out using a tightening sleeve and a suitable wrench.

[0066] Centering sleeve

[0067] The device advantageously comprises a centering sleeve 4 arranged between the first and second plates 10, 20 to guide the threaded rod 12 inside the centering sleeve 4.

[0068] The outer diameter of the centering sleeve 4 is adapted to the through hole 600 of the intermediate blade 6. The inner diameter of the centering sleeve 4 is adapted to the diameter of the threaded rod 12. The centering sleeve 4 therefore makes it possible to guide the posi operation of the threaded rod 12 inside the through hole 600 of the intermediate blade 6 when the centering sleeve 4 equips said through hole 600.

[0069] Rotation lock

[0070] The device advantageously comprises rotation locking means arranged to lock a rotation of the first and second buffers 1, 2 around the longitudinal axis A.

[0071] The rotation locking means advantageously comprise: - a plate 5, arranged between the first and second buffers 1, 2, and having first and second opposite surfaces 50, 51; the first surface 50 of the plate 5 facing the second surface 100 of the first plate 10; - first projecting elements 500, extending projecting from the first surface 50 of the plate 5 so as to block a rotation of the first buffer 1 around the longitudinal axis A; - second projecting elements 510, extending projecting from the second surface 51 of the plate 5 so as to block a rotation of the second buffer 2 around the longitudinal axis A.

[0072] The plate 5 is advantageously made of a metallic material, preferably aluminum or steel. However, other materials are conceivable, such as a composite material or a plastic material (for example polyetheretherketone PEEK). The plate 5 is provided with a through-hole 52 arranged to receive the threaded rod 12.

[0073] By way of non-limiting example, the first and second protruding elements 500, 510 may be produced in the form of claws. The claws may be rectangular in shape. The first protruding elements 500 advantageously extend along the edge of the first surface 50 of the first plate 5. The second protruding elements 510 advantageously extend along the edge of the second surface 51 of the plate 5.

[0074] According to an alternative not illustrated, it is possible to provide at least one mechanical axis (e.g. threaded rod of a screw, centering pin, etc.) for each of the first and second buffers 1, 2, said at least one mechanical axis being arranged to position the corresponding buffer 1, 2 in an orifice of the intermediate blade 6. Said at least one mechanical axis engaged in the orifice of the intermediate blade 6 makes it possible to block a rotation of the corresponding buffer 1, 2 around the longitudinal axis A. Multi-leaf spring

[0075] An object of the invention is a multi-leaf spring for equipping a suspension of a vehicle, comprising: - an upper blade, called the master blade; - a lower blade; - an intermediate blade 6, inserted between the upper blade and the lower blade, and having first and second opposite end portions 60 provided respectively with first and second through holes 600; - first and second devices in accordance with the invention; the threaded rods 12 of the first pads 1 of the first and second devices being respectively inserted into the first and second through holes 600; the first and second pads 1, 2 of the first and second devices being assembled in abutment against the intermediate blade 6 by the nuts 3 of the first and second devices.

[0076] Upper blade

[0077] The upper leaf is the master leaf. The upper leaf is the main member of the multi-leaf spring which holds the suspended load of the vehicle. The upper leaf is advantageously made of a metallic material, preferably steel.

[0078] Lower blade

[0079] The lower blade may be a reinforcing blade making it possible to reinforce the suspension of the rear axle of the vehicle and restore the vehicle's attitude. The lower blade may be a compensating blade. The compensating blade comes into action when the vehicle is loaded and makes it possible to compensate for the additional load. The lower blade is advantageously made of a metallic material, preferably steel.

[0080] Intermediate blade

[0081] The interposed blade 6 is interposed between the upper blade and the lower blade. The interposed blade 6 has first and second opposite end portions 60. The first end portion 60 of the interposed blade 6 is provided with a first through hole 600. The second end portion 60 of the interposed blade 6 is provided with a second through hole 600.

[0082] The intermediate blade 6 is generally a reinforcing blade. Thus, the lower blade can be: (i) an additional reinforcing leaf, in which case the multi-leaf spring may include a compensating leaf arranged under the lower leaf; (ii) a compensating blade.

[0083] The intermediate blade 6 is advantageously made of a metallic material, preferably steel.

[0084] Assembly of devices

[0085] The threaded rod 12 of the first buffer 1 of the first device is inserted into the first through hole 600. In the presence of a centering sleeve 4 equipping the first through hole 600, the threaded rod 12 of the first buffer 1 of the first device is inserted into the centering sleeve 4. The threaded rod 12 of the first buffer 1 of the second device is inserted into the second through hole 600. In the presence of a centering sleeve 4 equipping the second through hole 600, the threaded rod 12 of the first buffer 1 of the second device is inserted into the centering sleeve 4. The threaded rods 12 of the first buffers 1 of the first and second devices have a length along the longitudinal axis A strictly greater than the thickness of the through holes 600.

[0086] The first and second buffers 1, 2 of the first device are assembled to bear against the intermediate blade 6 by the nut 3 of the first device. More precisely, the first and second buffers 1, 2 of the first device are assembled to bear against the first end portion 60 of the intermediate blade 6 by the nut 3 of the first device. The second buffer 2 is fixed to the first buffer 1 of the first device by tightening against the first end portion 60 of the intermediate blade 6, by screwing the nut 3 of the first device onto the threaded rod 12 of the first buffer 1 of the first device. The nut 3 of the first device can be tightened using a tightening socket and a suitable wrench.

[0087] In the same way, the first and second buffers 1, 2 of the second device are assembled in abutment against the intermediate blade 6 by the nut 3 of the second device. More precisely, the first and second buffers 1, 2 of the second device are assembled in abutment against the second end portion 60 of the intermediate blade 6 by the nut 3 of the second device. The second buffer 2 is fixed to the first buffer 1 of the second device by tightening against the second end portion 60 of the intermediate blade 6, by screwing the nut 3 of the second device onto the threaded rod 12 of the first buffer 1 of the second device. The nut 3 of the second device can be tightened using a tightening socket and a suitable wrench.

[0088] According to one embodiment: - the first surfaces of the first plates 10 of the first buffers 1 are oriented towards the upper blade; - the threaded rods 12 of the first buffers 1 each have a length; - the second elastic coverings 21 of the second buffers 2 each have a thickness adjusted according to the length of the threaded rods 12 so that the threaded rods 12 are entirely contained inside the through openings 210, at a distance from the lower blade.

[0089] As mentioned previously, the length of the threaded rods 12 along the longitudinal axis A is mainly determined so as to be strictly greater than the thickness of the through holes 600 of the intermediate blade 6. The length of the threaded rods 12 along the longitudinal axis A is chosen so as not to be too great so that the thickness of the second elastic coatings 21 is not also too large so as to fully contain the threaded rods 12 inside the through openings, away from the lower blade. Suspension

[0090] An object of the invention is a suspension of a vehicle, comprising at least one multi-leaf spring according to the invention.

[0091] Of course, it is preferable to equip the suspension with two multi-leaf springs in accordance with the invention. Such a suspension is particularly suitable for vehicles whose rear axle is subjected to a load greater than 2000 kg.

[0092] The invention is not limited to the embodiments disclosed. Those skilled in the art are able to consider their technically operative combinations and to substitute equivalents for them.

Claims

Claims

1. Vibration and shock absorption device for equipping a multi-leaf spring with a suspension, the device comprising: - a first buffer (1), comprising: a first plate (10), having first and second opposite surfaces, a first elastic coating (11), extending over the first surface, a threaded rod (12), extending along the normal to the second surface (100);- a second pad (2), comprising: a second plate (20), having first and second opposite surfaces, and provided with a through-hole (201) arranged to receive the threaded rod (12), the second surface (200) of the second plate (20) facing the second surface (100) of the first plate (10), a second elastic coating (21), extending over the first surface of the second plate (20), and provided with a through-opening (210) arranged to face the through-hole (201), a nut (3), arranged to cooperate with the threaded rod (12) so as to assemble the second pad (2) to the first pad (1) when the through-hole (201) receives the threaded rod (12), the through-opening (210) being sized to receive the threaded rod (12) and the nut (3).;

2. Device according to claim 1, in which the through opening (210) is sized to receive a tightening sleeve of the nut (3).

3. A device according to claim 1 or 2, comprising a centering sleeve (4) arranged between the first and second plates (10, 20) for guiding the threaded rod (12) inside the centering sleeve (4).

4. Device according to one of claims 1 to 3, in which the threaded rod (12) extends along a longitudinal axis (A), the device comprising rotation locking means arranged to lock a rotation of the first and second buffers (1, 2) around the longitudinal axis (A).

5. Device according to claim 4, in which the rotation locking means comprise: - a plate (5), arranged between the first and second buffers (1, 2), and having first and second opposite surfaces (50, 51); the first surface (50) of the plate (5) facing the second surface (100) of the first plate (1); - first projecting elements (500), extending projecting from the first surface (50) of the plate (5) so as to block a rotation of the first buffer (1) around the longitudinal axis (A); - second projecting elements (510), extending projecting from the second surface (51) of the plate (5) so as to block a rotation of the second buffer (2) around the longitudinal axis (A).

6. Device according to claim 4 or 5, in which the first and second pads (1, 2) each have a cross-section to the longitudinal axis (A) of rectangular shape.

7. Device according to one of claims 1 to 6, wherein the threaded rod (12) is a threaded rod (12) of a fixing screw, the fixing screw being fixed to the first plate (10).

8. Multi-leaf spring for equipping a suspension of a vehicle, comprising: - an upper leaf, called a master leaf; - a lower leaf; - an intermediate leaf (6), interposed between the upper leaf and the lower leaf, and having first and second opposite end parts (60) provided respectively with first and second through holes (600); - first and second devices according to one of claims 1 to 7; the threaded rods (12) of the first buffers (1) of the first and second devices being respectively inserted into the first and second through holes (600); the first and second buffers (1, 2) of the first and second devices being assembled to bear against the intermediate leaf (6) by the nuts (3) of the first and second devices.

9. A multi-leaf spring according to claim 8, wherein: - the first surfaces of the first plates (10) of the first pads (1) are oriented towards the upper blade; - the threaded rods (12) of the first pads (1) each have a length; - the second elastic coverings (21) of the second pads (2) each have a thickness adjusted according to the length of the threaded rods (12) so that the threaded rods (12) are entirely contained inside the through openings (210), at a distance from the lower blade.

10. Suspension of a vehicle, comprising at least one multi-leaf spring according to claim 8 or 9.

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