Vehicle wheel HUB and vehicle

Abstract

A wheel hub is herein described in which an area (B'), located at the rear of the hub, is formed by slopes having different angles that provide the wheel hub with greater mechanical resistance to rotational fatigue, substantially reducing the cracks and other mechanical wear in and near area (B'). Said wheel hub also has an area (A'), located on the front face of the hub, which is a meeting area between two perpendicular surfaces and is formed by a retracted vertical wall and a rounded inclined rib having two smaller radii, allowing for better accommodation and coupling of a portion of a vehicle's rotor or brake disc (C). The new geometry, or topological optimization of these areas (A', B'), provides greater mechanical resistance to rotational fatigue to the hub, substantially reducing cracks and other mechanical wear in and near areas (A', B').

Description

[0001] VEHICLE WHEEL HUB AND VEHICLE

[0002] TECHNICAL FIELD

[0003]

[0001] The present invention relates to a vehicle wheel hub with an optimized machining profile so as to provide improved mechanical resistance, particularly to fatigue and especially rotational fatigue.

[0004] DESCRIPTION OF THE STATE OF ART

[0005]

[0002] Wheel hubs for vehicles usually have constructive geometries that aim to meet mechanical strength and durability requirements. In addition, it is interesting that their manufacturing process can be made easier, faster and at a lower cost.

[0006]

[0003] In this sense, some hubs and wheels are known in the prior art that attempt to achieve these objectives satisfactorily, such as those described in patent applications US 6866345 "Outboard ribbed wheel hub", FR 2904581 "Roue comprenant une jante, un moyeu, et un dispositif de raccordement de la jante au moyed' ("Wheel comprising a rim, a hub, and a device for connecting the rim to the hub") and EP 2267323 "Roller bearing".

[0007]

[0004] In document US 6866345, the described wheel hub has a cylindrical main body and a radial flange, with radial ribs extending between the outer side of the radial flange and the outer end of the main body. This wheel hub eliminates stress concentrations created by the design of the internal ribs of conventional wheel hubs. Sudden and drastic transverse changes in the profile of a radial flange create stress concentrations that increase the susceptibility to fatigue and metal wear. In particular, as seen in Figure 2, US 6,866,345 document, which shows a prior art conventional wheel hub, the end portion 128 of the ribs 126 of the conventional wheel hub 100 are machined to provide projections 130 for the wheel bolts. The change in profile, created by machining the ribs 126, creates stress concentrations at the junction between the ribs 126 and the projections 130.

[0008]

[0005] The inventive wheel hub proposed in US 6,866,345, shown in Figure 6, is for the front steering axle of a vehicle, with curve C having a radius of approximately 2.3 inches (58.4 mm) at the transition portion 219 from the main body 202 to the radial flange 218. However, the size and shape of curve C may vary depending on the size and load of the wheel hub capacity, as well as depending on other factors.

[0009]

[0006] The document FR 2904581 describes a wheel comprising a rim, a hub, and a device for connecting the rim to the hub. This invention seeks, for example, to prevent the initiation of the rim breakage at the connection level with a radius. More generally, the invention seeks to dynamically improve the mechanical strength of the wheel from the point of view of rotational fatigue.

[0010]

[0007] Document EP 2267323 describes a wheel hub bearing comprising a fixed member, a rotating member, and at least one row of rolling elements arranged between said members to allow their relative rotation. As shown in Figure 1 of said invention, a bottom portion 8 is laterally delimited on both sides by at least one rib 9 extending from an interface portion 4. In particular, rib 9 has an inner end 9b that forms a radius rl connecting with circumferential surface 1, said radius being capable of being maximized to limit local stress concentrations. Thus, recess 7 allows the overall weight to be minimized and mechanical strength to be provided by rib 9.

[0011] 008] However, the objects disclosed by the aforementioned US, FR, and EP documents still have disadvantages since they do not comprise ideal mechanical strength for certain applications. What is known in the prior art for a possible improvement in mechanical strength would involve a substantial increase in the volume / size of the hub or even the use of stronger raw materials, which would unnecessarily increase the cost of the part. In this sense, the present invention was developed, which will result in a substantial increase in the strength of the wheel hub through a change in the topological profile of said hub, without any other change that generates an increase in the cost of the part, such as an increase in volume / size or a change in raw material.

[0012] SUMMARY OF THE INVENTION

[0013]

[0009] The object of the present invention is to provide an optimized machining profile for any vehicle wheel hub, aiming to present better mechanical strength, especially against rotational fatigue. Furthermore, the present invention aims to provide a vehicle comprising said wheel hub.

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015] - Figure 1 is a cross-sectional side view of a prior art wheel hub, which is shown attached to a portion of a vehicle's brake rotor or disc, indicated by the letter C, where areas of interest A and B are outlined in dashed lines;

[0016] - Figure 2 is a cross-sectional side view of a prior art wheel hub, which is shown attached to a portion of a vehicle's brake rotor or disc, indicated by the letter C, with areas (A and B) of interest highlighted;

[0017] - Figure 3 is a cross-sectional side view of a wheel hub, as disclosed in the present invention, also shown attached to a portion of a vehicle's brake rotor or disc, indicated by the letter C, where areas of interest A' and B' are schematically shown.

[0018] - Figure 4 is a cross-sectional side view of a wheel hub as disclosed in the present invention, which is shown attached to a portion of a vehicle's brake rotor or disc, indicated by the letter C, with areas (A' and B') and angles of interest highlighted; - Figure 5 is a cross-sectional side view of a wheel hub also shown attached to a portion of a vehicle's brake rotor or disc, indicated by the letter C, where respective overlaps of the areas of interest A, A' and B, B' are schematically shown for comparison purposes;

[0019] - Figures 6 and 7 show perspective views of the rear and front faces of a prior art wheel hub, respectively; and

[0020] - Figures 8 and 9 show perspective views of the rear and front faces of a wheel hub, respectively, of an embodiment of the present invention.

[0021] - Figure 10 shows a rotational fatigue life simulation, in perspective views of the rear and front faces of a prior art wheel hub.

[0022] - Figure 11 shows a rotational fatigue life simulation, in perspective views of the rear and front faces of a wheel hub of one embodiment of the present invention.

[0023]

[0010] In Figures 1, 2, 3, 4, and 5, the rotor or brake disc portion C is shown only at the top of the hub. At the bottom of the hub, portion C has been omitted from the figures for greater clarity in viewing the aforementioned areas of interest.

[0024] DETAILED DESCRIPTION OF THE INVENTION

[0025] [Oil] The present invention will now be described in detail with reference to the attached figures to enable those skilled in the art to implement and use it. Various modifications of the described embodiment will be immediately apparent to those skilled in the art, and the general principles described can be applied to other embodiments and applications without departing from the scope of protection of the present invention, as defined by the claims. Therefore, the present invention should not be limited to the illustrated and described embodiments but it should be granted in a broadest scope of protection according to the features described and claimed herein.

[0026]

[0012] Figure 1 shows a cross-sectional side view of a prior art wheel hub, which is shown attached to a portion of a vehicle's brake rotor or disc, indicated by the letter C, where areas of interest A and B are circled with a dashed line. Area B is a rectilinear inclined surface at the rear of the hub and the area A, located on the front face of the hub, is an area where two perpendicular surfaces meet, said area being rounded and having a typical radius already common in the prior art and having a proportionally small magnitude in relation to the length of the aforementioned perpendicular surfaces. The rotor or brake disc portion C of the vehicle is coupled to said two perpendicular surfaces, and there is a notable gap between portion C and the area (A) where the two perpendicular surfaces meet. An exemplary bearing for coupling the wheel hub to the vehicle is indicated with the letter R.

[0027]

[0013] Figure 2 is a half-sectional side view of a prior art wheel hub, showing exemplary angles Z, X, and radii W, Y, which form areas of interest A and B. Regarding the area B, angle Z is approximately 145°, with a radius W and regarding the area A, angle X is approximately 90°, with a radius Y. The radii W and Y are of common and customary measurements in the prior art.

[0028]

[0014] According to a preferred embodiment, in the wheel hub of the present invention, shown in Figure 3, instead of a typical radius meeting between perpendicular surfaces (such as the aforementioned area A of the prior art), there is an area A' located on the front face of the hub, formed by a retracted vertical wall and a rounded inclined rib with two smaller radii, making it possible to better accommodate and couple the vehicle's rotor or brake disc portion C. At the same time, this new geometry provides the hub with greater mechanical resistance to rotational fatigue, substantially reducing cracks and other mechanical wear in and near area A'. With reference to the rear part of the hub of the invention, instead of a rectilinear surface with a single slope (such as the aforementioned area B in the prior art), there is an area B' formed by straight lines with inclinations at different angles which also provide the wheel hub with greater mechanical resistance to rotational fatigue, also substantially reducing the cracks and mechanical wear in general in and close to area B'. An exemplary bearing for coupling the wheel hub to the vehicle is indicated with the letter R.

[0029]

[0015] In this sense, as shown in figure 4, in the region of area A' the central curve has a radius Yl' between 8 and 20 mm, preferably 14 mm, and the ends have a radius Y2' and Y3' between 1.2 and 2.0 mm, preferably 1.6 mm, and the area A' also has lengths T', S' and U'. The angle X' is 122°. Furthermore, in regard to the region of area B', as already mentioned, this area is formed by straight lines with different inclinations, which form a first inclination angle Zl' between 156° and 166°, preferably 161°, comprising the angle between the two central straight lines, arranged so that their projections constitute concurrent straight lines, also forming a second opening angle Z2' between 140° and 150°, preferably 145°, which comprises the angle between the straight line at the outermost end of B' region (furthest from R bearing) and the inner central straight line (closest to R bearing), such straight lines also being arranged so that their projections constitute concurrent straight lines. Finally, there is a radius W2' between 4 and 8 mm, preferably 6 mm, between the outermost central straight line and the straight line at the outermost end as well as a radius Wl' between 2.0 and 3.0 mm, preferably 2.5 mm, at the meeting of the two central straight lines.

[0030]

[0016] Due to the different geometric construction, the angles of the new areas A', B' differ considerably from those of areas A, B, as is standard practice in the prior art.

[0031]

[0017] Therefore, the topological optimization provided by the profiles of these new areas A' and B', especially for metal parts with limited space constraints, can simply and efficiently maintain the original size and manufacturing cost of the wheel hub similar to the conventional prior-art solution, but with a considerable gain in mechanical resistance to rotational fatigue. Without such topological optimization, a solution to resistance to rotational fatigue would be an overall increase in part size (larger wheel hub / larger wheel bearing) or the use of a stronger raw material, resulting in a more difficult processing stage and unnecessarily increasing the weight (mass) and cost of the wheel hub.

[0032]

[0018] A comparison between a conventional prior-art wheel hub and a wheel hub as disclosed in the present invention showed numerical values obtained from tests and computer simulations — exemplified in Figures 10 and 11, which revealed a rotational fatigue life of approximately 190,000 rotational cycles for the prior art hub and a fatigue life of approximately 1,500,000 rotational cycles for the hub of the present invention. Therefore, there was an improvement of approximately 790% in terms of gaining useful life before the external crack appears due to rotational fatigue, in the topologically optimized hub of the present invention.

[0033]

[0019] Figure 5 shows a cross-sectional side view of a wheel hub coupled to a rotor or brake disc portion C, where the respective overlays of the areas of interest A, A' and B, B' are schematically shown to highlight the profile differences between the areas (A and B) of a prior art wheel hub and the areas (A' and B') of the wheel hub disclosed by the present invention.

[0034]

[0020] In Figures 6 and 7 are shown perspective views of the rear and front faces of a prior art wheel hub, respectively, and Figures 8 and 9 shown perspective views of the rear and front faces of a wheel hub of one embodiment of the present invention, respectively.

[0035]

[0021] The topologically optimized profiles of areas A' and B' of the wheel hub of this invention can be obtained through traditional machining, cold or hot forming, or even forging, without involving any special techniques and, therefore, enabling simple and quick adaptation or adjustment of the machinery used in manufacturing the hub. It is also worth noting that a particularly useful application of the hub of the present invention is in vehicle front wheels, although said hub can also be used, without any restrictions, in vehicle rear wheels, also with substantially improved mechanical resistance against rotational fatigue.

Claims

Claims / What is claimed is:

1. A wheel hub, wherein it has an area (A') located on the front face of the hub, formed by a retracted vertical wall and a rounded inclined rib with two smaller radii, allowing for the accommodation and coupling of a vehicle's rotor or brake disc portion (C) and having an area (B') located on the rear of the hub, formed by slopes with different angles.

2. The wheel hub, according to claim 1, wherein the area (A') has a central curve with a radius (Yl') between 8 and 10 mm, preferably 14 mm, and the ends have a radius (Y3') between 1.2 and 2.0 mm, preferably 1.6 mm. The area (B7) is formed by straight lines with different inclinations, comprising a first angle of inclination (Zl7) between 156° and 166°, preferably 161°, between the two central lines, arranged so that their projections constitute concurrent lines. There is also a second opening angle (Z27) between 140° and 150°, preferably 145°, between the straight line at the outermost end of the region (B7) and the inner central line, also arranged so that their projections constitute concurrent lines. The area (B7) also comprises a radius (W27) between 4 and 8 mm, preferably 6 mm, between the outermost central straight line and the straight line at the outermost end, in addition to a radius (Wl7) between 2.0 mm and 3.0 mm, preferably 2.5 mm, at the meeting of the two central straight lines.

3. A vehicle wherein it comprises at least one wheel hub as defined in claim 1.

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