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

Abstract

Vibration and shock absorption device for equipping a multi-leaf spring, comprising: - a first buffer (1), including: a first plate (10), a first elastic coating (11), a threaded rod (12); - a second buffer (2), including: 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 dimensioned 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 in 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 rigid axle type suspensions 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 the multi-leaf springs is to maintain the vehicle's suspended load in a flexible manner. The role of the shock absorbers is to absorb the energy stored, and then the energy released, by the multi-leaf springs. The shock absorbers prevent vehicle oscillations, for example, when the vehicle goes over a speed bump.

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

[0006] Several blade configurations are possible. 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, offering 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 travels on roads with significant irregularities or in extreme conditions. Other problems caused by blade friction include noisy squeaking that generates sound discomfort, or accelerated corrosion of the blades.

[0008] For this purpose, it is known from the prior art to use pads, generally made of a rubbery material, which are interposed between the blades in order to prevent them from rubbing together.

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

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

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

[0012] A threaded buffer is used for bi-leaf springs (an upper leaf and a lower leaf), and generally comprises: - a metal plate, covered 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 prior art buffer 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 leaf by the nut would lead to contact between the end of the threaded rod (and possibly the nut) and the lower leaf.

[0014] A sock plug is a hollow block made of rubber, having a through cavity whose shape coincides with the cross-section of the intercalated blade. The sock plug is threaded so as to enclose a portion (at the end or in the center) of the intercalated 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 plug may include at least one positioning pin (or lug) (also called a centering pin) made of rubber, arranged to cooperate with an opening in a blade.

[0015] Such a buffer, in the prior art, is not entirely satisfactory insofar as premature wear of the blades has been observed when the vehicle regularly travels on roads with significant irregularities or under extreme conditions (e.g., crossing bridges for an off-road vehicle, traversing steps, high-speed trails, etc.). Indeed, the sock-shaped buffer will inevitably slide from the outside of the intermediate blade towards the center of the intermediate blade (at the axle level), leaving the ends of the blades in direct contact. The sock-shaped buffer is more stable than a simple buffer due to the friction between the intermediate blade and the hollow rubber block, and to the conformity geometric stability between the cavity and the cross-section of the intercalated blade. However, this stability proves insufficient when the vehicle is used in extreme conditions. Description of the invention

[0016] The invention aims to remedy, in whole or in part, the aforementioned drawbacks. To this end, the invention relates to a vibration and shock absorption device for equipping a multi-leaf spring in a suspension, the device comprising: - a first stamp, comprising: a first plate, having first and second opposite surfaces, a first elastic coating, extending over the first surface, a threaded rod, extending along the normal to the second surface; - a second stamp, 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 orifice receives the threaded rod, the through opening being dimensioned 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 pad of the prior art, thanks to the cooperation of the nut and the threaded rod guaranteeing good mechanical hold; - to be used with a three-leaf spring, unlike a threaded buffer of the prior art, thanks to such a second buffer which prevents the end of the threaded rod (and nut) from coming into contact with the lower leaf; - It is mechanically fixed to an interlayer blade, unlike a sock-like pad of the prior art, thanks to the cooperation of the nut and the threaded rod which guarantees good mechanical strength. Indeed, the mechanical fixing (nut, threaded rod) prevents the device from slipping along the interlayer blade.

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

[0019] According to a feature of the invention, the through opening is dimensioned to receive a nut clamping sleeve.

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

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

[0022] Thus, one advantage is the excellent compatibility of the device with different types of leaves in a multi-leaf spring. The outer diameter of the centering sleeve can be adapted to the through hole of the intermediate leaf; the inner diameter of the centering sleeve can be adapted to the diameter of the threaded rod. The centering sleeve also ensures precise positioning of the various mechanical components of the device. Finally, the centering sleeve absorbs radial stresses that may be exerted on the threaded rod during rolling, in order to eliminate any excessive load on the threaded rod. A centering sleeve is also called a positioning sleeve.

[0023] According to one feature of the invention, the threaded rod extends along a longitudinal axis, the device includes means for locking against rotation arranged to block a rotation of the first and second buffers around the longitudinal axis.

[0024] Thus, one advantage is that it allows greater freedom in the shape and dimensions of the first and second buffers, without the risk of them protruding beyond the outer surface of the intermediate blade when installed transversely. In the absence of rotational locking mechanisms, the first and second buffers generally have a circular cross-section (relative to the longitudinal axis of the threaded rod), the diameter of which is less than the width of the intermediate blade. Consequently, the presence of such rotational locking mechanisms allows the use of first and second buffers with an oblong, for example, rectangular, cross-section. Such an oblong cross-section increases the effective surface area for absorbing vibrations and shocks of the device.

[0025] According to one feature of the invention, the means for blocking rotation comprise: - a plate, arranged between the first and second buffers, and having first and second opposing surfaces; the first surface of the plate facing the second surface of the first plate; - the first salient elements, extending outward from the first surface of the plate so as to block a rotation of the first buffer around the longitudinal axis; - second salient elements, extending outward 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 means of rotation blocking is the ease of their assembly with the other mechanical parts of the device at a reduced cost.

[0027] According to one feature of the invention, the first and second buffers each have a rectangular cross-section to the longitudinal axis.

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

[0029] According to one feature 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 placement on the first plate, the first plate allowing 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: - a top blade, called the master blade; - a lower blade; - an intercalated blade, inserted between the upper blade and the lower blade, and having first and second opposing end parts respectively equipped with first and second through holes; - the first and second devices conforming to 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 support against the intermediate blade by the nuts of the first and second devices.

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

[0033] The second pad is generally thicker than the first pad in order to contain the threaded rod inside the through-hole, away 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), particularly 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 vehicle suspension, comprising at least one 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 of 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 to say that the elastic coating can return to its initial shape when the mechanical stresses cease.

[0038] - By "thickness", we mean a dimension along the longitudinal axis of the rod threaded.

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

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

[0041] - By "through hole" is meant a hole passing through the end part of the blade intercalated within its thickness.

[0042] - "By "entirely contained within the through opening", it is meant that the stem The threaded rod of the first pad does not protrude from 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 accompanying drawings.

[0044] [Fig. 1] is a schematic side view, in exploded perspective, of a device according to the invention equipping an intercalated blade with a multi-leaf spring. For the sake of readability, the upper and lower blades are not shown, and only a portion (approximately half) of the intercalated blade is represented.

[0045] [Fig.2] is a schematic view analogous to [Fig.1], at an enlarged scale.

[0046] [Fig.3] is a schematic view analogous to [Fig.2], in a different orientation of the intercalated plate.

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

[0048] [Fig.5] is a schematic view analogous to [Fig.4], according to a different orientation of the intercalated plate.

[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 implementation methods

[0050] Identical elements or elements performing the same function shall bear the same reference numerals 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 in a suspension, the device comprising: - a first stamp 1, comprising: a first plate 10, presenting first and second opposing surfaces (only the second surface 100 is visible), 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 stamp 2, comprising: a second plate 20, having first and second opposing 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 orifice 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 orifice 201 receives the threaded rod 12, the through opening 210 being dimensioned to receive the threaded rod 12 and the nut 3.

[0052] First stamp

[0053] The first buffer 1 comprises: - a first plate 10, presenting 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 cost and mechanical resistance to friction. However, other materials are possible. By way of non-limiting examples, the first plate 10 can be made of a composite material or an engineering plastic. The composite material or the engineering plastic advantageously includes reinforcing fibers such as glass fibers or carbon fibers. The engineering plastic can, for example, be based on reinforced polyetheretherketone (PEEK), reinforced polyamide, or reinforced polypropylene. These alternative materials are, however, more expensive.

[0055] The first elastic coating 11 is advantageously made of an elastomeric material, preferably a rubber-type material. The first elastic coating 11 can be formed on the first plate 10 by a bonding technique. Bonding makes it possible, in particular, to obtain a high bond 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 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 an oblong cross-section about the longitudinal axis A, preferably rectangular in shape. In particular, the first elastic coating 11 advantageously has a rectangular cross-section about the longitudinal axis A. By way of non-limiting example, the first pad 1 may have a usable 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 opposing 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 the economic cost and mechanical resistance to friction. However, other materials are possible. By way of non-limiting example, the second plate 20 can be made of a composite material or an engineering plastic. The composite material or engineering plastic advantageously incorporates reinforcing fibers such as glass or carbon fibers. The engineering plastic can, for example, be based 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 rubber. The second elastic coating 21 can be formed on the second plate 20 by a bonding technique. Bonding makes it possible, in particular, to obtain a high bond 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 between 55 Shore A and 65 Shore A.

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

[0063] The second pad 2 advantageously has an oblong cross-section about the longitudinal axis A, preferably rectangular in shape. In particular, the second elastic coating 21 advantageously has a rectangular cross-section about the longitudinal axis A. By way of non-limiting example, the second pad 2 may have a usable 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 pad 2 to the first pad 1 when the through hole 201 receives the threaded rod 12. The nut 3 therefore has a shape and dimensions adapted to the diameter and thread of the threaded rod 12. The second pad 2 is fixed to the first pad 1 by tightening against the intermediate blade 6, by screwing the nut 3 onto the threaded rod 12. The nut 3 can be tightened using a socket and a suitable wrench.

[0066] Centering sleeve

[0067] The device advantageously includes 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 interlayer 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 allows the positioning of the threaded rod 12 to be guided inside the through hole 600 of the interlayer blade 6 when the centering sleeve 4 is fitted to said through hole 600.

[0069] Rotation lock

[0070] The device advantageously includes means for blocking rotation arranged to block a rotation of the first and second buffers 1, 2 around the longitudinal axis A.

[0071] The means for blocking rotation advantageously comprise: - a plate 5, arranged between the first and second buffers 1, 2, and having first and second surfaces 50, 51 opposite each other; the first surface 50 of the plate 5 facing the second surface 100 of the first plate 10; - the first salient elements 500, extending outward 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 salient elements 510, extending outward 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 possible, 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 can be made in the form of claws. The claws can 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 opening in the intermediate blade 6. Said at least one mechanical axis, engaged in the opening of the intermediate blade 6, prevents the corresponding buffer 1, 2 from rotating about the longitudinal axis A. Multi-leaf spring

[0075] An object of the invention is a multi-leaf spring for equipping a vehicle suspension, comprising: - a top blade, called the master blade; - a lower blade; - an intercalated blade 6, intercalated between the upper blade and the lower blade, and having first and second end parts 60 opposite, respectively provided with first and second through holes 600; - the first and second devices conforming to the invention; 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 in support 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 component of the multi-leaf spring that supports the suspended load of the vehicle. The upper leaf is advantageously made of a metallic material, preferably steel.

[0078] Lower blade

[0079] The lower leaf spring can be a reinforcing leaf spring, strengthening the rear suspension of the vehicle and restoring the vehicle's ride height. The lower leaf spring can also be a compensating leaf spring. The compensating leaf spring comes into action when the vehicle is loaded and compensates for the additional load. The lower leaf spring is advantageously made of a metallic material, preferably steel.

[0080] Intercalated plate

[0081] The intercalated plate 6 is intercalated between the upper plate and the lower plate. The intercalated plate 6 has opposing first and second end portions 60. The first end portion 60 of the intercalated plate 6 is provided with a first through hole 600. The second end portion 60 of the intercalated plate 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 blade, in which case the multi-leaf spring may include a compensating blade arranged under the lower blade; (ii) a compensating blade.

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

[0084] Assembly of devices

[0085] The threaded rod 12 of the first pad 1 of the first device is inserted into the first through hole 600. If a centering sleeve 4 is fitted to the first through hole 600, the threaded rod 12 of the first pad 1 of the first device is inserted into the centering sleeve 4. The threaded rod 12 of the first pad 1 of the second device is inserted into the second through hole 600. If a centering sleeve 4 is fitted to the second through hole 600, the threaded rod 12 of the first pad 1 of the second device is inserted into the centering sleeve 4. The threaded rods 12 of the first pads 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 pads 1, 2 of the first device are assembled against the intermediate blade 6 by the nut 3 of the first device. More precisely, the first and second pads 1, 2 of the first device are assembled against the first end portion 60 of the intermediate blade 6 by the nut 3 of the first device. The second pad 2 is attached to the first pad 1 of the first device by tightening the nut 3 of the first device 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 pad 1 of the first device. The nut 3 of the first device can be tightened using a socket and a suitable wrench.

[0087] Similarly, the first and second pads 1, 2 of the second device are assembled against the intermediate blade 6 by the nut 3 of the second device. More precisely, the first and second pads 1, 2 of the second device are assembled against the second end portion 60 of the intermediate blade 6 by the nut 3 of the second device. The second pad 2 is attached to the first pad 1 of the second device by tightening it 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 pad 1 of the second device. The nut 3 of the second device can be tightened using a socket and a suitable wrench.

[0088] According to one embodiment: - 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 buffers 1 each have a length; - the second elastic coatings 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 within 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 intercalated 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 great so as to contain the threaded rods 12 entirely inside the through openings, at a distance from the lower blade. Suspension

[0090] An object of the invention is a vehicle suspension, 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 according to the invention. Such a suspension is particularly suitable for vehicles whose rear axle is subjected to a load exceeding 2000 kg.

[0092] The invention is not limited to the embodiments described. A person skilled in the art is able to consider their technically operative combinations, and to substitute equivalents for them.

Claims

Demands

1. Vibration and shock absorption device for equipping a multi-leaf spring of a suspension, the device comprising: - a first buffer (1), comprising: a first plate (10), having first and second opposing surfaces, a first elastic coating (11), extending over the first surface, a threaded rod (12), extending along the normal to the second surface (100) and along a longitudinal axis (A);- a second pad (2), comprising: a second plate (20), having first and second opposing 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 dimensioned to receive the threaded rod (12) and the nut (3), the device being characterized in that it comprises means for rotationally locking arranged to block a rotation of the first and second buffers (1, 2) around the longitudinal axis (A).;

2. Device according to claim 1, wherein the through opening (210) is dimensioned to receive a nut clamping sleeve (3).

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

4. A device according to any one of claims 1 to 3, wherein the rotation-blocking means comprise: - a plate (5), arranged between the first and second buffers (1, 2), and having first and second surfaces (50, 51) opposite each other; the first surface (50) of the plate (5) facing the second surface (100) of the first plate (1); - first salient elements (500), extending outward 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 salient elements (510), extending outward 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).

5. Device according to any one of claims 1 to 4, wherein the first and second buffers (1,2) each have a rectangular cross-section with respect to the longitudinal axis (A).

6. Device according to any one of claims 1 to 5, wherein the threaded rod (12) is a threaded rod (12) of a fixing screw, the fixing screw being fixed to the first plate (10).

7. Multi-leaf spring for equipping a vehicle suspension, comprising: - an upper leaf, called the master leaf; - a lower leaf; - an intermediate leaf (6), interposed between the upper leaf and the lower leaf, and having first and second opposing end parts (60) having respectively first and second through holes (600); - first and second devices according to any one of claims 1 to 6; 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 in support against the intermediate leaf (6) by the nuts (3) of the first and second devices.

8. Multi-leaf spring according to claim 7, wherein: - the first surfaces of the first plates (10) of the first buffers (1) are oriented towards the upper leaf; - the threaded rods (12) of the first buffers (1) each have a length;

9. - the second elastic coatings (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 within the through openings (210), at a distance from the lower blade. Vehicle suspension, comprising at least one multi-leaf spring according to claim 7 or 8.

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