Noise prevention elements for spring bundles

Abstract

The anti-noise element (EAR) is applied to overlap the spring bundle (FM) and separate the ends of each two adjacent spring blades (LM), and comprises a metal plate (10) covered with a coating (20) of polyamide-11 thermosetting resin and incorporating a central protrusion (12) that fits and is held in a corresponding hole (F) provided in the end of the spring blade (LM) on which the anti-noise element (EAR) is seated and held.

Description

[Technical Field]

[0001] The present invention, in the nature of a utility model, relates to an element, usually applied in the suspensions of vehicles and road equipment, generally vehicles for transporting goods or passengers, placed between the blades of a spring bundle, for reducing or eliminating the noise caused by the frictional movement between adjacent spring blades of the spring bundle when the suspension is in operation during the movement of the vehicle. [Background technology]

[0002] Latest Technology Spring bundles applied to road vehicles are known in the state of the art and each comprise an assembly of spring blades of equal or separate lengths mounted one on top of the other, which flex relative to one another in response to a load applied to them.

[0003] These widely used spring bundles of spring blades present the disadvantage that the frictional movement of adjacent spring blades in each bundle as they flex under the different loads imposed on them by the moving vehicle creates a loud and unpleasant noise, which is particularly unpleasant for vehicle passengers.

[0004] According to one known structural solution for these anti-noise elements, each element is formed by a plate or blade, usually rectangular and / or circular in profile, made of polymeric material and / or composite rubber, with or without reinforcing additives in its composition, and presents a width adjusted to the width of the blades of the spring bundle and a longitudinal extension of the bundle sufficient to prevent direct contact between the ends of each two adjacent spring blades of the spring bundle. Each element incorporates at least one projection that fits into a corresponding hole provided in the adjacent spring blade of each pair of blades separated by the anti-noise element, ensuring the correct positioning of the element within the spring bundle.

[0005] These anti-noise elements, made of polymeric materials and / or composite rubber, have a limited service life because the loads and / or friction to which they are subjected can cause the material to be expelled or worn away until they malfunction, which can lead to the spring bundle anti-noise element being dislodged or its displacement between the two blades towards the central region of the spring blades, causing premature destruction of the spring bundle blades. In either case, the anti-noise element loses its function.

[0006] In another known construction of anti-noise elements, each element is formed by a metal plate or sheet, incorporating on its upper surface a layer of composite rubber by bonding, vulcanization or other suitable means, and on its lower surface at least one lower positioning projection, generally metal, e.g., a stud, which fits and locks into a corresponding hole provided in the lower spring blade of each pair of blades separated by the anti-noise element. This composite element also has a width adjusted to the width of the blades of the spring bundle and a longitudinal extension just sufficient to prevent direct contact between the ends of two adjacent spring blades of each spring bundle.

[0007] These elements, formed in metal sheets and carrying rubber pads, also have a limited service life due to wear caused by friction and the workload to which the rubber pads are subjected. Furthermore, these elements with rubber pads are usually held in a spring bundle by studs and nuts, which requires a longer manufacturing time and increases the cost of the product compared to polymer soundproofing elements.

[0008] Another known structure is disclosed in patent application BR-A-0503283. In this case, each anti-noise element comprises a rectangular steel blade of reduced thickness, with a width and length corresponding to those of two adjacent blades of the spring bundle between which the element is attached. At least its ends are coated on top and bottom with a layer of elastomeric material, preferably defined by vulcanized rubber but which can be made from various synthetic or natural materials. The anti-noise element can be in the form of a smooth metal blade held in place within the spring bundle by a conventional pin or central rod that passes through all the blades and by a conventional retaining clamp installed within the spring bundle. Furthermore, the steel blade element can include a protrusion on one side, formed in the form of a rib, and a corresponding recess on the opposite side.

[0009] This previous construction, besides presenting the same drawbacks of the solution using metal sheets carrying rubber pads, also suggests the use of a steel blade extending over the entire length of the pair of spring blades to which it is attached, substantially increasing the construction costs of the spring bundle and unnecessarily increasing its final weight. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Brazilian Patent Application Publication No. 0503283 Summary of the Invention [Problem to be solved by the invention]

[0011] Due to the drawbacks of known solutions as mentioned above, the present invention aims to provide a simple structure, relatively low cost, easy and safe assembly of a bundle of layered springs, and to provide an increased service life compared to known construction solutions. [Means for solving the problem]

[0012] The present noise prevention element will now be described below with reference to the accompanying drawings. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 represents a side elevational view of one end of a typical bundle of spring blades provided with a noise prevention element according to the invention and arranged between the respective ends of two adjacent spring blades. [Figure 2] FIG. 2 is an isometric exploded perspective view showing the end of a spring blade and a corresponding anti-noise element seated and held on the spring blade according to a first embodiment. [Figure 3] FIG. 3 represents an isometric perspective view of the noise prevention element according to the first embodiment thereof shown in FIG. [Figure 4] FIG. 4 shows a cross-sectional view of the anti-noise element, which is shown in cross section along line IV-IV of FIG. 3 and is mounted between two adjacent spring blades. [Figure 5] 10 depicts an isometric perspective view of a noise prevention element configured according to a second embodiment. [Figure 6] FIG. 6 represents a cross-sectional view of the anti-noise element in its second embodiment, which element is shown in cross section along line VI-VI of FIG. 5 and is mounted between two adjacent spring blades. DETAILED DESCRIPTION OF THE INVENTION

[0014] Description of the Invention As previously mentioned and shown in the accompanying drawings, the present noise prevention element EAR is arranged between the ends of each two spring blades LM of a spring bundle FM, which spring bundle FM is typically applied in the suspensions of vehicles and road equipment and is formed by an assembly of spring blades LM. In the illustrated configuration, the spring blades LM have different lengths, although it is possible to use spring blades LM of the same length to form the spring bundle FM. The spring blades LM are mounted one above the other, with or without retaining elements ER with an alignment function known in the art.

[0015] It should be understood that the term spring blade defines not only spring blades that act as suspension springs, but also final safety spring blades that are located in the lower region of the spring bundle and that do not act as suspension springs as much as additional safety elements in the event of a spring bundle failure, and which may comprise one or more suspension spring blades.

[0016] According to the invention, each anti-noise element EAR comprises a metal plate 10 of variable contour, polygonal, circular or elliptical shape, of steel or of any suitable alloy, the maximum width of which corresponds to the overall width of the spring bundle FM, with or without a retaining element ER, and having, in the longitudinal direction, an extension approximately equal to that width and sufficient to prevent direct contact between the overlapping ends of two adjacent spring blades LM.

[0017] In the two illustrated embodiments, each metal plate 10 has a thickness that is smaller than that of a spring blade LM, generally less than half the thickness of the adjacent spring blade LM, and each metal plate 10 is covered with a coating 20 in the form of a layer of thermoplastic resin known as polyamide-11, the thickness of which ranges from 0.01 mm to 2.00 mm and varies depending on the dimensional characteristics of the spring blades LM of the spring bundle FM to which the noise prevention element EAR will be applied.

[0018] The coating 20, thanks to the use of a thermosetting resin defined by polyamide-11, is defined by dipping or any other suitable process and can be used for any type of spring bundle FM, making it possible to obtain an anti-noise element that is easy to construct and assemble, is cost-competitive and exhibits superior durability when compared to that of currently known solutions. The coating 20 is shown in part on the anti-noise element EAR (see Figures 2, 3 and 5).

[0019] As shown in Figures 3 and 4, in a first embodiment, the anti-noise element EAR can be defined by a metal plate 10, the dimensions of width, length and thickness of which are defined above, and which, in the construction shown, incorporates a central protrusion 12 defined by a central recess 11, said central protrusion 12 designed to fit and be held against displacement in a corresponding hole F provided in the end of the spring blade LM on which the anti-noise element EAR sits and is held.

[0020] In the example of Figures 3 and 4, the central lead-in 11 produces a central projection 12 defined by a pair of parallel ribs 12a spaced apart in the longitudinal direction of the spring bundle FM, which fit into holes F in the ends of each spring blade LM and ensure the correct and safe positioning of the anti-noise element EAR on the spring bundle FM.

[0021] 5 and 6 show a second embodiment of the noise prevention element EAR, which exhibits similar features to the first embodiment shown in FIGS. 3 and 4 and is labeled with the same reference numerals. However, in this second embodiment, the metal plate 10 incorporates, at each longitudinal edge, a side flap 15 that seats against the adjacent side edge of the upper or lower spring blade LM adjacent thereto in the spring bundle FM. In FIG. 6, only the seating of the side flap 15 of the metal plate 10 against the side edge of the spring blade LM located directly above is shown. However, it should be understood that the metal plate 10 can be installed in an inverted position relative to that shown in FIG. 6, with its side flap 15 positioned directly below against the opposite edge of the spring blade LM. Thus, in the proposed structure in which the metal plate 10 incorporates side flaps 15, the retaining element ER shown in FIG. 1 can be completely or partially removed from the spring bundle FM.

[0022] In both the first and second embodiments, preferably the entire metal plate 10, including the central projection 12 and the final side flaps 15, is covered with a coating 20 of polyamide-11, avoiding any direct metal contact between the anti-noise element itself and the two adjacent spring blades LM.

[0023] Only two embodiments of the noise prevention element of the invention are presented herein, but variations can be made in the shape and arrangement of the component parts of the element without departing from the proposed concept.

Claims

1. A noise prevention element for a spring bundle of the type formed by an assembly of spring blades (LM) attached one above the other, with end portions of each of two adjacent spring blades (LM) separated by a respective noise prevention element (EAR) provided with a metal plate (10), the metal plate having a width adapted to the overall width of the spring bundle (FM) and a length preventing direct contact between the overlapped portions of the ends of two adjacent spring blades (LM), said metal plate (10) comprising:

1. A noise prevention element incorporating a central lug (12) defined by a central recess (11) defined by a pair of parallel ribs (12a) spaced apart and arranged in the longitudinal direction of the spring bundle (FM), the pair of parallel ribs (12a) fitting into corresponding holes (F) provided in the end of the spring blade (LM) on which the noise prevention element (EAR) is seated and held, characterized in that the entire metal plate (10) including the central lug (12) is covered by a coating (20) in polyamide-11.

2. 2. Noise prevention element according to claim 1, characterized in that the coating (20) is defined by a polyamide-11 resin layer having a thickness of between 0.01 mm and 2.00 mm.

3. 3. A noise prevention element according to claim 1 or 2, characterized in that the metal plate (10) has a thickness that is less than the thickness of the spring blade (LM).

4. 4. A noise prevention element according to claim 1, wherein the metal plate (10) incorporates at each longitudinal edge a side flap (15) which rests above, in the spring bundle (FM), directly adjacent to the adjacent side edge of the spring blade (LM), and each side flap (15) is covered with a coating (20) in polyamide-11.

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