Brake spider, method for manufacturing same, and drum brake system

Abstract

The present invention pertains to the fields of mechanical, metallurgical, and materials engineering, and nanotechnology. More specifically, the invention discloses a brake spider and a method for manufacturing same by casting. The brake spider of the invention, which is provided with an optimized geometric configuration, has notable properties, such as improved mechanical properties combined with reduced weight, resulting in exponential performance gains and consequently promoting vehicle braking safety.

Description

Brake spider, its manufacturing process, and drum brake system. Field of Invention

[0001] The present invention falls within the fields of mechanical, metallurgical and materials engineering, and nanotechnology. Background of the Invention

[0002] The incorporation of particles into molten metals is a technical difficulty that has not yet been satisfactorily resolved, and is the subject of intensive studies.

[0003] In the specific field of cast iron, various approaches have been studied and attempted to improve the properties of the final product. One approach is to try to incorporate nanoparticles of various materials. However, the large-scale use of nanoparticles still faces multiple limitations, starting with the unavailability of nanoparticle preparations with high concentration, purity, precise particle size distribution, or even simple availability in large quantities. Furthermore, there are several other technical problems that limit the industrial use of nanoparticles, including the tendency to aggregate, the difficulty of dispersion, the risks associated with eventual dispersion in the air / environment, and the still poorly understood effects resulting from human or animal contact with nanoparticles.

[0004] The problem of difficulty in mixing / dispersing / homogenizing additives, particularly those containing nanoparticles, in the processing of metals and special steels has been known for some time, with different approaches to try to solve it. The present invention shows a solution to this problem.

[0005] Additionally, applications of said metallic materials are highly desirable. Therefore, the present invention also addresses this. highly desirable and necessary applications in the state of the art.

[0006] In the context of drum brake systems, there is a structural component known as a brake spider, which functions to support and position other system components, such as the brake shoes and the S-shaft, close to the brake drum.

[0007] State-of-the-art brake spiders (Figures 21 and 22) typically have different geometries designed for the front and rear axles of the vehicle, as well as the left and right sides of the axle. Although these conventional examples share a central hole for fitting to the vehicle axle, their geometric configurations vary depending on the axle (front or rear) and side (left or right), which leads to greater complexity and cost in the production and assembly of the brake system.

[0008] As an alternative to the prior art, document CN204284262U presents a brake spider for a drum brake system, equipped with structural ribs positioned between two holes at one end of the spider. Between these holes is a central hole for receiving a component of the ABS system. Furthermore, there are structural reinforcements between a larger central hole and a hole for receiving the S-shaft at the opposite end of the spider. Therefore, the brake spider of CN204284262U is symmetrical and can be used on any wheel of the vehicle, but it requires the reinforcement elements located in the most critical regions of the spider in relation to mechanical stresses.

[0009] Similar to CN204284262U, document US2015122603A1 presents a pneumatic brake system for heavy vehicles, where a brake spider has a central circular opening with a periphery equipped with multiple holes. However, CN204284262U and US2015122603A1 do not explore material or manufacturing characteristics of the spider.

[0010] Other solutions are even further removed from the present invention, such as: the brake spider of document US6772865B2 showing holes around the central opening, lacking a passage for the component of ABS system; and the brake spider of US20100193303, manufactured in steel by means of stamping processes to obtain two parts of the spider joined by welding, differing from the present invention by presenting additional joining and / or post-treatment steps.

[0011] Thus, prior art relating to brake spiders shows similar geometries, in which the material (e.g., steel) fills practically the entire perimeter of the larger diameter central hole, resulting in an increase in the total mass of the part. When such prior art deals with aspects relating to the material or the manufacturing steps employed, it is observed that several steps subsequent to stamping or casting are usually required, such as annealing and tempering, among other heat treatments, to modify the mechanical properties of the structure.

[0012] In this sense, the state of the art lacks a brake spider that possesses geometric characteristics in harmony with its composition and manufacturing process, in order to promote structural optimization and facilitate its production, resulting in gains in the mechanical properties of the spider and in productivity, as well as benefits to the environment.

[0013] Thus, based on the literature reviewed, no documents were found that anticipated or suggested the teachings of the present invention, so the solution proposed here has novelty and inventive activity compared to the state of the art. Summary of the Invention

[0014] Thus, the present invention presents a geometric configuration for a brake spider comprising an optimized isotropic geometry, made possible by a cast iron alloy comprising a mass quantity of niobium nanoparticles used for the manufacture of said brake spider. This geometry of the present invention is differentiated mainly in its central region, in order to provide structural optimization aimed at greater durability and structural resistance of the brake spider. and consequently, safety in vehicle braking. After the casting stage based on these constructive characteristics (geometry and manufacturing material), the brake spider is ready for use in the brake system, eliminating the need for additional thermal processes.

[0015] This isotropic geometry confers interchangeability to the brake spider of the invention, so that the same spider is applicable to the front or rear axle of the vehicle, as well as to the left or right side of the axle. Furthermore, the central region of the brake spider has an extended opening, both in the transverse and vertical directions, allowing the use of an ABS-type braking system.

[0016] Compared to prior art products, the present invention enables reduced shrinkage cavities, improved particle homogenization in the casting, standardization of metal alloys (baseline), and / or the production of parts with complex geometries.

[0017] Furthermore, it is also worth highlighting the reduction in the weight of parts produced in the present invention, and the combination of weight reduction along with improvements in the geometric and mechanical properties of the part of the present invention results in an exponential gain in performance when compared to parts of the prior art.

[0018] In a first object, the present invention presents a brake spider comprising an isotropic geometric configuration endowed with a central region provided with a mixed contour opening.

[0019] Another object of the invention is a process for manufacturing a brake spider comprising the step of casting a cast iron alloy, forming the direct-application brake spider.

[0020] Yet another object of the invention is a drum brake system for a vehicle, wherein the brake system comprises a brake drum associated with a brake spider comprising an isotropic geometric configuration having a central region provided with a mixed contour opening.

[0021] These and other objects of the invention will immediately gain value. Those versed in the art will be described in detail below. Brief Description of the Figures

[0022] The following figures are presented:

[0023] Figure 1 presents an embodiment of the brake spider of the present invention, illustrating a front view.

[0024] Figure 2 shows a front perspective view of a second embodiment of the brake spider of the present invention.

[0025] Figure 3 shows a rear perspective view of the embodiment of Figure 2.

[0026] Figure 4 shows a side view of the embodiment of Figure 2.

[0027] Figure 5 shows a metallographic analysis image of a prior art cast iron composed of a base alloy, showing the distribution of nodules in the nodular cast iron.

[0028] Figure 6 shows a metallographic analysis image of a cast iron composed of a base alloy comprising niobium nanoparticles, highlighting the enhanced distribution of nodules in the nodular cast iron with niobium nanoparticles.

[0029] Figure 7 shows a metallographic analysis image of a cast iron composed of a second base alloy comprising niobium nanoparticles, highlighting the even more enhanced distribution of nodules in nodular cast iron with niobium nanoparticles.

[0030] Figure 8 shows a metallographic analysis image of the cast iron indicated in Figure 7, etched with 3.5% Nital.

[0031] Figure 9 illustrates a tensile test on a cast iron part made from the first base alloy.

[0032] Figure 10 illustrates a tensile test on the part manufactured from cast iron composed of the second base alloy.

[0033] Figure 11 illustrates a tensile test on the cast iron part made from the alloy of the present invention.

[0034] Figure 12 highlights regions A, B, and C of the brake spider selected for the hardness test. The measurements were performed on a specimen in its as-cast state, without machining, indicating the regions selected for obtaining the hardness values.

[0035] Figure 13 shows cross-sections of the brake spider of the invention for inspection in the soundness test.

[0036] Figure 14 shows another view of the brake spider sections of the invention for inspection in the soundness test.

[0037] Figure 15 shows an embodiment of the manufacturing of the brake spider of the present invention by casting.

[0038] Figure 16 illustrates a bench setup for conducting a fatigue test.

[0039] Figure 17 shows a realization of the assembly illustrated in Figure 16.

[0040] Figure 18 illustrates a sample after performing a fatigue test followed by a non-destructive evaluation using penetrant liquids, which showed the absence of cracks or defects.

[0041] Figure 19 illustrates another sample after the fatigue test, showing failures under high load application.

[0042] Figure 20a illustrates a sample that also showed failures after performing the fatigue test with the application of a high load.

[0043] Figure 20b refers to the sample in Figure 20a shown in detail.

[0044] Figure 20c refers to the sample in Figure 20a, indicating the location of the fault.

[0045] Figure 20d indicates the beginning of the crack precipitation shown in the sample in Figure 20c.

[0046] Figure 21 shows the geometries of state-of-the-art brake spiders, illustrating the geometric differences between front and rear brake spiders, as well as the differences between the two rear brake spiders themselves.

[0047] Figure 22 shows a state-of-the-art brake spider.

[0048] Figure 23 illustrates a simplified diagram of conventional equipment for performing a fatigue test. Detailed Description of the Invention

[0049] Compared to prior art products, the present invention enables reduced shrinkage cavities, improved particle homogenization in the casting, standardization of metal alloys (baseline), and / or the production of parts with complex geometries.

[0050] Furthermore, it is also worth highlighting the reduction in weight of parts produced in the present invention, and the combination of weight reduction along with improvements in the geometric and mechanical properties of the part of the present invention results in an exponential gain in performance when compared to parts of the prior art. Consequently, with this performance gain of the brake spider implemented in a vehicle braking system, the invention promotes safety in vehicle operation.

[0051] Thus, in a first object, the present invention provides a brake spider comprising an isotropic geometric configuration. For the purposes of the present invention, the isotropic geometric configuration provides an interchangeable part, so that the brake spider of the invention can be used on both the front and rear axles of the vehicle, as well as on the left or right side of the axle.

[0052] The geometric configuration of the brake spider has a central region with at least one first hole (1) around an opening (10). This central region is located between two end regions of the brake spider, where one of them has a second hole (20) and the opposite end region has at least one third hole (30).

[0053] The said opening (10) in the central region of the brake spider has a mixed contour. In one embodiment, the opening (10) is a slot, gap or hole for the passage and fitting of a vehicle axle. In one embodiment Additionally, the opening (10) also allows for the fitting of other components, such as a component of an ABS type brake system, for example, an ABS sensor. Thus, the brake spider of the invention expands its applicability to different types of axles and axle sides.

[0054] These benefits are based on the optimized geometry provided by the invention. The optimized geometry focuses on the central region of the brake spider provided with the mixed contour opening (10). For the purposes of the present invention, the mixed contour of the opening (10) defines a non-circular, irregular or non-uniform periphery. Mixed contour is understood to be the sequence of surfaces tangent to the opening (10) that have varying directions and / or dimensions (e.g., thickness and width). In one embodiment, the mixed contour opening (10) is delimited by curved, straight edges / faces and / or a combination thereof. Thus, in one embodiment, the opening (10) has an approximately polygonal shape, which extends between the lateral regions and between the end regions of the brake spider.

[0055] Based on this, in the present invention, the topologically optimized geometry provides a more organic structure with reduced mass compared to prior art solutions. In this sense, the opening (10) in the central region also has widened side walls (2). In one embodiment, the two side walls (2) are widened towards the lateral regions of the spider, so that these walls (2) widen the opening (10) in relation to its center, generating a wider brake spider body at the edges. In another embodiment, the side walls (2) have a smaller thickness compared to the other portions of the brake spider, optimizing the structure to reduce its mass without loss of performance. In another embodiment, the side walls (2) are thin and positioned further away from the center of the opening (10), while the end regions are located closer to this center.

[0056] Furthermore, the opening (10) in the central region has at least one concavity (4) located between the side walls (2). In one embodiment, The opening (10) has a concavity (4) facing the second hole (20). In a further embodiment, the opening (10) has another concavity (4) facing the third holes (30). With this, the vehicle axle is inserted in the center of the opening (10) aligned with the concavities (4), maintaining enlarged free spaces between the axle and each widened side wall (2) for fixing components of the ABS system, for example.

[0057] Around the opening (10) and between the side walls (2), there are areas for fitting, fixing and / or passing components of the drum brake system. In this embodiment, the brake spider has at least one first connection hole (1) located adjacent to the opening (10) in the central region. In this embodiment, the first holes (1) receive the brake drum.

[0058] Additionally, in one embodiment, the second hole (20) located in one of the end regions of the spider allows for fitting with an S-axis. In another embodiment, the third hole (30) in the opposite end region is associated with the brake shoe. In a complementary embodiment, the brake spider has additional holes (3) in the end regions and / or side walls (2), for example, for fixing a support, such as an S-axis support. In one embodiment, next to the second hole (20), the brake spider has at least one pair of additional holes (3). In a complementary embodiment, a rib (5) is located between two additional holes (3) that are on the same side as the second hole (20).

[0059] Therefore, the brake spider of the invention features axes of symmetry that allow its application on both the right and left sides of vehicle axles, defining its interchangeability characteristic. Furthermore, the optimized geometry of the brake spider of the present invention allows for the standardization of the geometric configuration of brake spiders applied to both the front and rear axles of the vehicle. In one embodiment, the brake spider is implemented on a steering and / or drive axle. In another embodiment, the brake spider is implemented on a passive axle. In one embodiment, the brake spider is applicable to different types of axles, which These variations are mainly found in heavy-duty vehicles, such as trucks and road implements. This versatility of the brake spider in the invention stems from the spaces provided by its optimized geometry.

[0060] This geometric configuration of the spider of the invention is permitted by its manufacturing process and material. Furthermore, thanks to the present invention, the assembly and manufacturing of the brake system in a vehicle are facilitated, since the brake spiders are identical, regardless of their application position on the axle (left / right side), whether it is the front / rear axle, drive / passive axle, etc.

[0061] In a further embodiment, the vehicle model is not a limiting factor for the present invention, since the drum brake system of the invention is applied to vehicles ranging from light to heavy-duty.

[0062] To that end, the brake spider of the invention is manufactured from a cast iron alloy comprising particles of niobium species. In the context of the present invention, the expression "niobium species" encompasses various chemical entities containing niobium, including metallic niobium, oxides, hydrates, hydrides, carbides, or nitrides of niobium, iron niobium or niobium alloyed with other metals or transition metals, or combinations thereof. It also includes niobium pentoxide (Nb2O5), NbC, NbO, FeNb, niobium oxalate, and niobic acid. These may be microparticles, submicroparticles, or nanoparticles. Said particles (micro, submicro, or nano) of niobium species are used as dopants, additives, or fillers to the base material of the brake spider. In one embodiment, the base material of the brake spider of the present invention is a cast iron alloy.

[0063] In one embodiment, the brake spider comprises a cast iron alloy comprising a mass quantity of niobium nanoparticles. In one embodiment of the brake spider, said niobium nanoparticles are composed of NbO, NbÜ2, or Nb2Ü5. In one embodiment of the brake spider, said niobium nanoparticles are composed of Nb2Ü5.

[0064] In a concrete embodiment of the brake spider, the aforementioned quantity in The mass of niobium nanoparticles comprises an amortization level of at least 19%. In one embodiment of the brake spider, said nanoparticle mass preferably comprises an amortization level of at least 19%, more preferably at least 25%, more preferably at least 30%, more preferably at least 35%, more preferably at least 39%, more preferably at least 40%, more preferably at least 45%, more preferably at least 50%, more preferably an amortization level of at least 55%, more preferably at least 59%, more preferably at least 65%, and even more preferably an amortization level of at least 70%. In one embodiment, the amortization level of at least 71%, more preferably at least 72%, most preferably at least 73%. In a non-limiting embodiment, the amortization rate is 74%.In one embodiment of the brake spider, the aforementioned mass quantity of niobium nanoparticles preferably comprises an amortization degree of at least 39%, preferably an amortization degree of at least 59%, and even more preferably an amortization degree of at least 74%.

[0065] In a second object, the present invention discloses a brake spider manufacturing process comprising a casting step of a cast iron alloy. In one embodiment, the manufacturing process forms a brake spider with an isotropic geometric configuration as defined above. From this, the invention process forms a direct-application brake spider, using a material formed from a cast iron alloy.

[0066] For the purposes of the present invention, the direct-application brake spider is a part that is ready for use and assembly in the brake system after the manufacturing process, once the desired mechanical and structural properties resulting from casting have been achieved. Therefore, the invention process eliminates the need for subsequent heat treatments. In one embodiment, the manufacturer does not need to subject the part to annealing, hardening, tempering, etc., since the produced part already possesses the desired properties. Chemical composition and microstructure adjusted to provide the hardness, strength, and ductility necessary to generate the optimized brake spider geometry as defined previously and as per the proof-of-concept examples discussed below.

[0067] Thus, the composition of the brake spider without heat treatment provides performance equivalent to heat-treated alloys. Furthermore, the invention provides cost and production time savings, as well as contributing to environmental protection by eliminating post-manufacturing steps commonly employed in the prior art.

[0068] Thus, the invention discloses a brake spider and its manufacturing process, using a metallic material comprising the incorporation of Niobium nanoparticles and possessing an optimized and interchangeable isotropic geometry. The brake spider of the invention exhibits remarkable properties, such as improved mechanical properties combined with reduced weight, resulting in an exponential performance gain. In one embodiment, the alloy used in the invention is called Steeron, as it has steel-like characteristics even though it is cast iron.

[0069] In one embodiment, the manufacturing step forms the following isotropic geometric configuration of the brake spider: at least one first mounting hole (1) for mounting on a brake drum; an opening (10) for fitting with a vehicle axle, wherein the opening (10), as a through hole, comprises recesses positioned symmetrically to each other, which form side walls (2) and concavities (4) to define a mixed contour of the opening (10); a second through hole (20) for mounting with an S-axle; at least two symmetrical holes (30) for mounting with brake shoes; and at least one additional hole (3) for mounting with the S-axle support.

[0070] In one embodiment, the manufacturing of said geometric configuration of the brake spider allows for the standardization of a single brake spider model to be associated with both the front and rear axle brake drums. as well as on both the right and left sides of the vehicle. In one embodiment, the recesses that define the side walls (2) create a free space to allow for the attachment of ABS system components, for example, in addition to reducing the thickness of the walls (2).

[0071] Furthermore, standardizing the geometry of the brake spider allows for optimization of the production line in the factory, reducing manufacturing time.

[0072] In one embodiment, the manufacture of thin walls (2) of the brake spider provides mass reduction and optimization of the part geometry.

[0073] In one embodiment, the brake spider is manufactured with niobium nanoparticles composed of NbO, NbÜ2, or Nb2Ü5. In a more specific embodiment, the aforementioned niobium nanoparticles are composed of Nb2Ü5.

[0074] In one embodiment, the mass of niobium nanoparticles comprises an amortization level of at least 19%. In a more specific embodiment, the mass of nanoparticles preferably comprises an amortization level of at least 39%, preferably an amortization level of at least 59%, and even more preferably an amortization level of at least 74%.

[0075] The invention process, being of low complexity due to the casting step without the need for additional heat treatments, also allows for an optimized geometry, with a complexity in relation to the previous technique, as previously defined for the brake spider of the invention. In one embodiment, the geometric configuration of the brake spider of the invention allows for direct demolding after casting, eliminating the need for subsequent rework or machining.

[0076] In a third embodiment, the present invention provides a drum brake system having a brake drum associated with a brake spider. This association, as well as other associations between the brake spider and the other components of the brake system, are achieved by permanent or non-permanent union. In one embodiment, the brake spider of the brake system is manufactured by the process as defined above.

[0077] It is also an object of the invention a vehicle comprising a brake drum, the brake drum being associated with at least one brake spider, wherein the brake spider comprises an isotropic geometric configuration.

[0078] The aforementioned isotropic geometric configuration of the brake spider provides standardization of the brake spider configuration, allowing its association on both the front and rear axles of the vehicle, and on both the left and right sides of the vehicle.

[0079] The examples shown here are intended only to illustrate some of the various ways of carrying out the invention, without limiting its scope.

[0080] Examples

[0081] Example 1 - Niobium nanoparticle preparation process

[0082] A Labstar LS01 stirred ball mill (Netzsch) was fed with micrometric particles of niobium pentoxide. The process involved high-energy wet milling. The particle suspension was 17.7 wt%, consisting of approximately 3500 g of milli-Q water + 10 M NaOH and 750 g of the solid sample, which was prepared and stabilized in the mill's mixing tank at pH 9 and titrated with 10 M NaOH. The milling spheres used were yttria-stabilized zirconia, 400 µm in diameter. The milling chamber was filled to 80% vol. and the suspension temperature was below 40 °C. The mill rotation speed was set to 3000 rpm and milling was conducted for 8 hours. To stabilize the suspension at pH 9, 10 M NaOH was added during milling, with samplings taken periodically and particle sizes measured.

[0083] In the present example, several embodiments of niobium pentoxide nanoparticle preparations were obtained, with a purity greater than 99%. Commercial niobium pentoxide, with the particle size distribution described in Table 1, was pre-comminuted in a high-energy mill containing yttria-stabilized zirconia beads with a diameter of 400 µm, in liquid medium, and the pH adjusted to 6.6. The mill rotation speed was 3500 rpm and the Particle grinding was conducted at a temperature below 40 °C. Table 1 shows the particle size distribution (PSD) of niobium pentoxide input (commercial product) and output from a pre-comminution step. Table 1 - Input and output DTP after pre-comminution.

[0084] The average specific surface area S (m 2 The mass of the particles after the pre-comminution step was 0.32 m / g. 2 / g.

[0085] In one embodiment, the pre-comminuted particles were then The nanoparticles were fed into a high-energy mill under conditions similar to those described above, but with 200 µm Zr spheres and ground for different times, until each nanoparticle preparation was obtained. Three different nanoparticle preparations were obtained, each with a defined particle size distribution as described in Table 2. Table 2 - Particle size distribution of three different preparations (C, D and E) of niobium pentoxide nanoparticles.

[0086] Further details on the process for obtaining the nanoparticles can be found in patent application BR112023003019 of the inventors of the present application. In the examples of the present application, samples were used that were subjected to 12 hours of grinding.

[0087] Without intending to be bound by theory, it is understood that the samples subjected to 12 hours of grinding, which exhibit a higher degree of amortization (74%), contribute to the surprising effects presented.

[0088] Example 2 - Process for preparing cast iron alloys

[0089] Details regarding the process for obtaining cast iron alloys can be found in patent application BR102023011061-4 of the inventors of the present application. In the examples of the present application, samples were used that were subjected to 12 hours of grinding.

[0090] Example 3 - Example of a brake spider implementation comprising nanoparticles

[0091] The embodiments of the cast iron brake spider comprising niobium pentoxide nanoparticles can be found in Figures 1 to 4, with their specific characteristics shown in detail in said figures.

[0092] The brake spider developed in this example has an isotropic geometry, allowing for interchangeability of the spider. Compared to the brake spiders of the prior art (figures 21 and 22), the geometric configuration of the developed brake spider provides standardization of the brake spider configuration, and can be applied to both the front and rear axles of the vehicle, and to both the left and right sides of the vehicle. Also in this comparison, the geometric configuration presents a central region with a non-circular opening (10), differing from the prior art. In one embodiment, the opening (10) has a contour in the shape of two mirrored “omegas”.

[0093] The brake spider has: four initial mounting holes (1) for mounting on a brake drum; the opening (10) for fitting the axle of vehicle; two tapered walls (2) positioned symmetrically to each other; a second through hole (20) for fitting with an S-axis; two symmetrical holes (30) for fitting with brake shoes; and four second holes (3) for fitting to an S-axis support.

[0094] The first holes (1) are positioned next to the opening (10) in a quadrangular arrangement, closer to the side wall (2) than to the center of the opening (10), which receives the vehicle axle. For this, from the center, the opening (10) extends between two concavities (4), one of them facing the second hole (20) located at one end of the spider and the other facing the symmetrical holes (30) at the opposite end of the spider. Thus, each of the first holes (1) is positioned in the curved region located between each wall (2) and each of the concavities (4).

[0095] Furthermore, the side walls (2) are also widened, providing free space to accommodate other components, such as the ABS system fixed between the vehicle axle and one of the walls (2). Thus, the walls (2) provide mass relief and optimization of the brake spider geometry. In addition, the walls (2) have reduced thickness, contributing to the reduction of the brake spider mass.

[0096] In figures 1 to 4, it can be observed that the brake spider holes are projected in opposite directions. Additionally, between the plane of the opening (10) and the plane of the symmetrical holes (30) there is a difference in level, so that the symmetrical holes (30) are projected to the same side as the first holes (1), while the second hole (20) and the additional holes (3) are projected to the opposite side.

[0097] Comparatively, the second embodiment (figures 2 to 4) presents an even more optimized geometric configuration in relation to the first embodiment when observing the recesses (7) and protrusions (6), which are positioned adjacent to the first holes (1), to accommodate the vehicle axle.

[0098] Among the advantages of the brake spider of the present invention, in addition to Among the improved physical properties resulting from the developed alloy material and the proposed new isotropic geometry, the reduction in weight compared to state-of-the-art brake spiders stands out, resulting in several advantages for the vehicles to which they are applied.

[0099] In Brazil, commercially sold cast iron brake spiders weigh around 8.55 kg. The brake spider in this example, however, weighs 5.13 kg, representing a 40% reduction in mass.

[0100] The combination of weight reduction and improved mechanical properties of the part of the present invention results in an exponential performance gain when compared to brake spiders of the prior art. Such a performance gain from the present invention would be readily recognized by a person skilled in the art.

[0101] Example 4 - Comparative metallographic analysis of nodular cast irons

[0102] Images were also obtained through metallographic analysis of the tested alloys.

[0103] Figure 5 shows a metallographic analysis image of a prior art cast iron composed of a base alloy, highlighting the distribution of nodules in the nodular cast iron.

[0104] Figure 6 shows a metallographic analysis image of a cast iron composed of this first base alloy comprising niobium nanoparticles, highlighting the enhanced distribution of nodules in the nodular cast iron with niobium nanoparticles.

[0105] Based on the images mentioned above, it is possible to observe an improvement in the number of nodules, i.e., 157 nodules / mm². 2 for 219 nodules / mm 2 (central region). Additionally, it is possible to observe a substantially more uniform dispersion of the nodules throughout the nodular cast iron matrix and, furthermore, a substantially more uniform distribution of the nodule sizes.

[0106] Without desiring to be bound by theory, it is understood that the distribution A substantially more uniform (dispersion of nodules and distribution of their sizes) contributes to the increases in the mechanical properties tested.

[0107] In this sense, Figure 7 shows a metallographic analysis of a cast iron composed of a second base alloy, indicating a greater distribution of nodules in the nodular cast iron with niobium nanoparticles, reaching 353 nodules / mm². 2 For comparative purposes with the sample in Figure 7, an etching with 3.5% Nital was performed, revealing the alloy microstructure illustrated in Figure 8.

[0108] Thus, the microstructure results for the cast iron alloy of the present invention showed: 99% pearlite, 97% modularity, and a nodule count of 353 nodules / mm². 2 .

[0109] Example 5 - Tensile, hardness and soundness tests

[0110] From this, the present invention reveals a nanostructured metallic alloy containing 0.12% premix addition. In comparison with the first and second base alloys mentioned previously, Table 3 presents the tensile results, demonstrating a significant increase in the mechanical strength of the alloy of the present invention in relation to the first and second base alloys. Table 3 - Traction Results

[0111] The graphs in Figures 9 and 10 refer, respectively, to the first and second base alloys, while Figure 11 refers to the alloy of the present invention with the addition of niobium, illustrating the behavior of the brake spider during tensile tests.

[0112] Additionally, Figure 12 highlights three regions of the brake spider of the invention: (A) connection region with the brake shoe, (B) connection region with the brake drum, and (C) connection region with the S-shaft. The Brinell hardness results obtained in these regions were 236 HB, 237 HB, and 241 HB, respectively. Considering that these values ​​remain close to each other, the hardness test shows a homogeneous distribution of the nanoparticles, indicating satisfactory dispersion of the premix and absence of local segregation. In other words, the analyzed results point to a uniformity of hardness resulting from the adequate dispersion of the nanoparticles in the metallic matrix.

[0113] Additionally, a metallographic soundness analysis was performed, which showed no signs of porosity, shrinkage cavities, or other structural discontinuities, as illustrated in Figures 13 and 14. These results confirm the microstructural integrity of the obtained nanostructured alloy, demonstrating the efficiency of the premix incorporation process and the quality of the brake spider of the invention as shown in the embodiment of Figure 15.

[0114] Example 6 - Cyclic tests

[0115] This example deals with tests performed on the durability of the brake spider of the invention, based on a test using a device known as a Chucker, which verifies the dimensional and structural integrity of a part under real braking conditions, using the entire brake system assembly under severe conditions.

[0116] Figure 23 shows a simplified diagram of the Chucker device that receives the brake spider, drum, brake lining, and other brake system components, causing wear on them as well as the spider itself. From this, an actuator applies force to the brake assembly. This conventional test requires a very long execution time, sometimes weeks to complete.

[0117] Alternatively, the following workbench assembly was developed according to the design illustrated in Figure 16 and the implementation shown in Figure 17. where a central device receives only the brake spider for connection to three hydraulic actuators varying the applied force. This allowed for more intense simulations representing more severe conditions applied to the brake spider, since the invention's test has more actuators compared to the common Chucker which has only one actuator. Thus, the test performed is based on the conventional test, with the implementation of modifications to execute the test more efficiently and with greater mechanical stress capacity in relation to the magnitude of the applied forces, directions, vibration frequency, etc.

[0118] Furthermore, another advantage of the equipment used compared to Chucher is the shorter fatigue test time, requiring only 3 hours.

[0119] Table 4 summarizes the durability results obtained using the described setup. After the test, photos of the samples shown in Figures 18 to 20d were taken. Table 4 - Durability test results for brake spiders

[0120] For samples 1, 2, and 3, the tests were performed under reduced load in order to provide better data correlation between the apparatus of the common Chucker (1 actuator) and the bench designed (3 actuators) for the invention. These samples did not present cracks or defects. Furthermore, sample 3 represents a prior art sample for comparative purposes on the brake spider of the invention (samples 1 and 2) under reduced load, where No occurrences were observed even after exceeding a high number of cycles compared to sample 3.

[0121] The same occurs with the brake spider of the invention in sample 4 with nominal load, with no recorded occurrences. This nominal load is equivalent to the chucker signal.

[0122] Thus, in order to visualize the occurrence of failures, the load applied to the brake spider of the invention was increased in samples 5 and 6, where sample 5 without the addition of niobium showed cracking after 38,100 cycles and rupture at 44,177 cycles, while sample 6 with the addition of niobium showed crack initiation at 80,630 cycles, crack propagation at 94,000 cycles and rupture at 133,442 cycles.

[0123] Therefore, the images in the following figures show the samples after their respective tests:

[0124] - Figure 18 refers to sample 1, with no abnormalities observed;

[0125] - Figure 19 refers to sample 5, allowing us to verify that the failure occurred in the same location and with the same failure pattern as commercial brake spider models; and

[0126] - Figures 20a to 20d refer to sample 6, indicating the start of the crack as shown by the arrow in Figure 20d.

[0127] Therefore, the tests validate the concept of the invention by proving the performance of the brake spider of the invention with an optimized geometry, manufactured by casting.

[0128] Example 7 - Cyclic tests with high load

[0129] In order to demonstrate the durability of the brake spider of the present invention in relation to the brake spider of the prior art, further cyclic tests were carried out, applying a high load through the equipment illustrated in Figures 16 and 17.

[0130] Table 5 presents the durability results obtained using samples of brake spiders from the prior art and the present invention. Table 5 - Results of durability tests on brake spiders under high load.

[0131] Thus, the results of the tests in this example validated the concept of the invention, presenting a brake spider that is competitive with commercial products.

[0132] Those skilled in the art will appreciate the knowledge presented here and will be able to reproduce the invention in the forms presented and in other variants and alternatives, covered by the scope of the following claims.

Claims

Claims 1. Brake spider characterized by comprising an isotropic geometric configuration endowed with a central region provided with an opening (10) of mixed contour.

2. Brake spider, according to claim 1, characterized in that the opening (10) of the central region comprises at least one enlarged side wall (2).

3. Brake spider, according to claim 2, characterized in that the opening (10) of the central region comprises at least one concavity (4) disposed between the side walls (2).

4. Brake spider, according to claim 1, characterized by comprising at least one first connection hole (1) disposed adjacent to the opening (10) of the central region.

5. Brake spider, according to claim 1, characterized by being manufactured from a cast iron alloy comprising particles of Niobium species.

6. Manufacturing process for a brake spider characterized by comprising a casting step of a cast iron alloy, forming the direct-application brake spider.

7. Process according to claim 6, characterized in that the cast iron alloy comprises particles of niobium species.

8. Process according to claim 7, characterized in that the said niobium species is selected from: NbO, NbC, Nb2Ü5, niobic acid, niobium oxalate, FeNb or combinations thereof.

9. Process, according to claim 6, characterized in that the formed brake spider comprises an isotropic geometric configuration having a central region provided with an opening (10) of mixed contour.

10. Drum brake system for a vehicle, wherein the brake system comprises a brake drum, associated with a brake spider, and is characterized by the brake spider comprising an isotropic geometric configuration having a central region provided with an opening (10) of mixed contour.

11. Brake system according to claim 10, characterized in that the brake spider is manufactured by the process defined in claim 6.

12. Brake system, according to claim 10, characterized in that the brake spider comprises at least one first hole (1) for connection to the brake drum, the first hole (1) being disposed adjacent to the opening (10) of the central region of the brake spider.

13. Brake system, according to claim 10, characterized in that the opening (10) of the central region of the brake spider receives a vehicle axle and comprises at least: a. an enlarged side wall (2); and b. a concavity (4) disposed between the side walls (2).

14. Brake system, according to claim 10, characterized in that the brake spider is manufactured from a cast iron alloy comprising particles of niobium species.

Images