Brake disc for motor vehicle

Abstract

The invention relates to a brake disc (1) for a motor vehicle, the brake disc (1) comprising an inner hub (11) intended to be coupled to a wheel hub, an outer flange (12) extending radially around the inner hub (11), the outer flange (12) forming a friction surface intended to collaborate with a complementary clamping member of the brake disc (1), a ventilation device configured to facilitate the cooling of the outer flange (12), the ventilation device comprising a plurality of grooves (13) extending along the outer flange (12), each groove (13) opening on either side of the outer flange (12) relative to an axis of rotation (O1) of the disc brake. According to the invention, each groove (13) has an air flow direction inclined relative to the axis of rotation (O1), so that the ventilation direction (DV) forms a non-zero angle with the axis of rotation (O1).Figure to be published with the abstract: Fig. 1.

Description

Title of the invention: Brake disc for a motor vehicle

[0001] The technical context of the present invention is that of motor vehicle braking devices. More particularly, the invention relates to a brake disc equipped with a ventilation system.

[0002] In the prior art, brake discs are known which comprise a pair of mutually spaced annular discs and which form two opposing flat brake contact surfaces. When such brake discs are implemented on a braking system for a motor vehicle, then, in the event of activation of the braking system, these opposing brake contact surfaces receive a braking force applied by a brake caliper via two opposing brake pads.

[0003] During braking, the brake discs then experience frictional forces and heat buildup. The brake pads and disc brake may become worn or damaged due to thermal degradation and material fatigue caused by the cyclical application of friction braking. In addition, prolonged heating of the brake discs may lead to a reduction in braking performance, which is not acceptable.

[0004] In a known manner, the integration of ventilation systems in known brake discs is known in order to increase heat transfer between the brake disc subjected to such heating and the ambient air. Thus, by circulating around the brake disc, calories are transferred from the brake disc to the ambient air, thus reducing heating and allowing cooling of the brake disc.

[0005] Document US2005098398A1 is known in particular, which describes a brake disc for bicycle braking systems, said brake disc comprising an external peripheral portion, a hub portion, and an air circulation device provided on said brake disc, and inclined relative to said brake disc, for propelling and circulating air around said brake disc when said brake disc rotates. Thus, this known brake disc comprises grooves which extend through the external peripheral portion to improve the heat transfer between the air and the brake disc. This brake disc is however used in the bicycle field and not in the automobile field.

[0006] In the automotive field, several approaches are known to improve the cooling of the brake disc and to limit its heating during use. In particular, grooved brake discs are known. Such brake discs have numerous surface grooves arranged on the contact surface between the brake disc and the associated brake pad, in order to increase friction and thus promote cooling of the brake disc. Perforated brake discs are also known. Such brake discs have a plurality of holes arranged on the contact surface between the brake disc and the brake pad, in order to increase friction and thus promote cooling of the brake disc. In addition, these holes facilitate the flow of rainwater. These known brake discs are not very efficient and do not allow good cooling of the brake disc, especially during intensive use.

[0007] Finally, ventilated brake discs are also known, which have an empty space between the two faces of the brake disc, thus promoting the circulation of air between the two faces and the ventilation of the brake disc. The disadvantage of such known ventilated brake discs lies in their complexity and their high manufacturing costs.

[0008] The object of the present invention is to propose a new brake disc in order to address at least a large part of the above problems and to further lead to other advantages.

[0009] Another object of the invention is to improve the cooling of the brake disc.

[0010] Another object of the invention is to facilitate the manufacture of such a brake disc and to reduce manufacturing costs.

[0011] According to a first aspect of the invention, at least one of the aforementioned objectives is achieved with a brake disc for a motor vehicle, the brake disc comprising:

[0012] - an inner hub intended to be coupled to a wheel hub;

[0013] - an outer flange extending radially around the inner hub, the flange exterior forming a friction surface intended to collaborate with a complementary clamping member of the brake disc;

[0014] - a device for ventilating the brake disc, the ventilation device being configured to facilitate cooling of the outer flange when the brake disc is in use, the ventilation device comprising a plurality of grooves extending along the outer flange, each groove opening on either side of the outer flange relative to an axis of rotation of the disc brake.

[0015] According to the invention, each groove has an air flow direction inclined relative to the axis of rotation.

[0016] In the context of the present invention, an axis of rotation of the brake disc is defined as an axis parallel to the axis of the wheel that the brake disc according to the invention is intended to equip. The axis of rotation of the brake disc according to the first aspect of the invention is substantially perpendicular to a plane of extension of the outer flange of the brake disc. The axis of rotation is also located at the center of the outer flange. In the context of the present invention, the adjective "axial" refers to a direction taken parallel to the axis of rotation.

[0017] In the context of the present invention, the radial direction is defined as any direction perpendicular to the axis of rotation. The radial direction means a distance taken from the axis of rotation of the brake disc. In the context of the present invention, the adjective "radial" refers to any direction taken perpendicular to the axis of rotation.

[0018] In the context of the present invention, the outer flange forms an annular structure which extends radially outside and around the inner hub. The outer flange thus forms at least one friction plane intended to interact with the complementary clamping member of a braking system. The outer flange is integral with the inner hub. The outer flange and the central hub are advantageously made of the same material, i.e. from the same manufacturing process, so that it is not possible to separate them without damaging or destroying the outer flange and / or the inner hub.

[0019] In the context of the present invention, the inner hub is an interface part with the wheel hub. The inner hub can take any shape. In particular, relative to an axial direction, the inner hub can be flat or curved.

[0020] In the context of the present invention, the ventilation device makes it possible to cool the brake disc when it is stressed by the clamping member, in order to dissipate the calories resulting from the friction between the outer flange and the clamping member. Thus, the ventilation device allows air to circulate through the outer flange, in order to propel and circulate the air around the brake disc when said brake disc rotates. In a particularly clever manner, the grooves forming the ventilation device are inclined relative to the axis of rotation, so as to increase the heat exchange surface between the outer flange and the air circulating through said grooves.

[0021] In the context of the present invention, the flow direction is defined by a ventilation direction of the groove through the outer flange. The ventilation direction is a line which extends between a front face and a rear face of the groove, taken on either side of the outer flange. More particularly, the ventilation direction is the line which connects each analogous point of the front face and the rear face of the groove. More particularly, the ventilation direction connects for example the center of the front face of the groove to the center of the rear face of said groove. The invention thus provides that this ventilation direction is inclined relative to the axis of rotation, that is to say that the ventilation direction is not parallel to the axis of rotation, so that the groove is arranged in a direction not perpendicular to the front face or to the rear face of the outer flange.This configuration is particularly advantageous because it lengthens the depth of the groove and allows . to increase the exchange surface between the inner flange and the air circulating in the groove, thus optimizing the cooling of the brake disc.

[0022] The brake disc according to the first aspect of the invention advantageously comprises at least one of the improvements below, the technical characteristics forming these improvements being able to be taken alone or in combination:

[0023] - The inner hub is of the type of a solid hub or a spoke hub, each branch extending radially from a central portion of the inner means and towards the outer flange.

[0024] The inner hub comprises a device for fixing to the wheel hub. The fixing device comprises a plurality of through holes intended to cooperate with fixing screws and the wheel hub.

[0025] - the grooves are angularly regularly distributed around the axis of rotation. This advantageous configuration thus promotes uniform cooling of the brake disc and, more particularly, of its outer flange;

[0026] - each groove is axially delimited by a front face and a rear face located respectively on a front face and a rear face of the outer flange, the front face of a groove being axially offset relative to the rear face of said groove. In the context of the present invention, the brake disc has a generally discoidal shape, providing two contact surfaces with the clamping member, the two contact surfaces being parallel to each other. Also, these two contact surfaces form the front face and the rear face of the outer flange of the brake disc, and the groove passes through the brake disc from one side to the other in an axial direction, so as to comprise a front face on the front face of the outer flange and a rear face on the rear face of the outer flange;

[0027] - a ventilation direction of each groove extends intersectingly by relative to the axis of rotation. As mentioned previously, the ventilation direction is a line which extends between a front face and a rear face of the groove, taken on either side of the outer flange. More particularly, the ventilation direction connects for example the center of the front face of the groove to the center of the rear face of said groove;

[0028] - the ventilation direction of each groove is not perpendicular to the face front and / or rear face of the outer flange. Conversely, the ventilation direction of each groove has a non-zero angle with the axis of rotation. Consequently, a depth of the groove, taken along the ventilation direction and between the front face and the rear face of the outer flange, is greater than a thickness of the outer flange measured along the axis of rotation. This configuration is particularly advantageous because it makes it possible to increase the surface area of ​​the lateral edges of the groove in the outer flange, thus increasing the heat exchange surface and promoting more efficient cooling of the brake disc;

[0029] - preferably, the ventilation direction has an angle of between 40° and 50° relative to a front face and / or a rear face of the outer flange. Optionally, all the grooves are oriented in the same ventilation direction, so that the ventilation direction of a given first groove is parallel to the ventilation direction of all the other grooves. This advantageous configuration makes it possible to facilitate the manufacture of the brake disc according to the invention, by reducing manufacturing times and manufacturing costs. Alternatively, the ventilation directions of the grooves are different from each other;

[0030] - according to a preferred embodiment of the invention, the ventilation direction of the grooves form an angle between 40° and 50° relative to the axis of rotation of the brake disc. This advantageous configuration forms a better compromise between the desired thermal performance and ease of manufacturing;

[0031] - each groove has an oblong shape. In particular, according to a first alternative embodiment, each groove extends along a rectilinear director profile. According to a second alternative embodiment, each groove extends along a curved director profile. Generally, all the grooves have identical shapes and dimensions. Alternatively, the grooves have different shapes and dimensions;

[0032] - each groove extends mainly radially along the flange of brake. This advantageous configuration thus makes it possible to promote uniform cooling of the outer flange of the brake disc, and in particular in the radial direction. In particular, the grooves are angularly inclined in a clockwise direction, relative to the axis of rotation. This advantageous configuration thus makes it possible to lengthen the grooves so that they are greater than a radial dimension of the outer flange.

[0033] - according to a preferred embodiment of the invention, a width of the groove is between 1 mm and 5 mm. Advantageously, each groove has a width between 2 mm and 3 mm. In the context of the present invention, the width of a groove is measured perpendicular to its two lateral edges;

[0034] - a length of the grooves, taken according to their director profile, is between 50 mm and 150 mm, preferably between 80 mm and 120 mm.

[0035] According to a second aspect of the invention, a braking system for a motor vehicle is proposed, the braking system comprising a brake disc according to the first aspect of the invention or according to any of its improvements and a clamping member configured to be pressed against the outer flange of the brake disc.

[0036] Advantageously, although not limiting of the invention, the clamping member is of the type of a caliper comprising at least one brake pad.

[0037] According to a third aspect of the invention, there is provided a motor vehicle comprising a braking system in accordance with the second aspect of the invention.

[0038] Various embodiments of the invention are provided, integrating according to all of their possible combinations the different optional characteristics set out here.

[0039] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0040] [Fig-1] illustrates a perspective view and from its front face of an example of a sheave brake disc assembly according to the first aspect of the invention;

[0041] [Fig.2] illustrates a perspective view and from its rear face of the brake disc illustrated in [Fig.l] as well as a detail view;

[0042] [Fig.3] illustrates a transparent view of the brake disc of [Fig.l].

[0043] Of course, the features, variants and different embodiments of the invention may be combined with each other, in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0044] In particular, all the variants and all the embodiments described can be combined with each other if nothing prevents this combination from a technical point of view.

[0045] In the figures, the elements common to several figures retain the same reference.

[0046] With reference to FIGURES 1 to 3, the invention relates to a brake disc 1 for a motor vehicle, the brake disc 1 comprising:

[0047] - an inner hub 11 intended to be coupled to a wheel hub;

[0048] - an outer flange 12 extending radially around the inner hub 11, the outer flange 12 forming a friction surface intended to collaborate with a complementary clamping member of the brake disc 1;

[0049] - a device for ventilating the brake disc 1, the ventilation device being configured to facilitate the cooling of the outer flange 12 when the brake disc 1 is used, the ventilation device comprising a plurality of grooves 13 extending along the outer flange 12, each groove 13 opening on either side other of the outer flange 12 relative to an axis of rotation 01.

[0050] The inner hub 11 here forms an interface part with the wheel hub. The inner hub 11 forms an inner flange which can be solid or partially hollowed out. In the embodiment shown in [Fig. 1], the central hub comprises several branches 111 which extend radially outwards, from a central part towards a radially inner edge of the outer flange 12. Each branch 111 extends substantially along a radius of the brake disc 1, and two adjacent branches 111 delimit between them a recess 112.

[0051] In the embodiment shown in [Fig.l], the outer flange 12 forms a circular ring which extends radially outside the inner hub 11. The outer flange 12 is of course integral with the inner hub 11. The outer flange 12 is preferably made of the same material as the inner hub 11.

[0052] The outer flange 12 forms two planes which extend parallel to each other and perpendicular to the axis of rotation 01. Each of its planes respectively forms a front face 120 and a rear face 121 for the outer flange 12. The front face 120 and / or the rear face 121 forms a friction surface with a clamping member of a braking system with which the brake disc 1 is intended to collaborate, thus making it possible to produce effective braking by friction between the brake disc 1 and said clamping member.

[0053] As mentioned previously, such friction braking generates heating of the brake disc 1 which must be dissipated to guarantee the physical integrity of the brake disc 1 as well as the expected braking performance. To this end, the ventilation device of the brake disc 1 comprises grooves 13, one air flow direction of which is inclined relative to the axis of rotation 01. The flow direction is here determined by the straight line connecting a front face 131 of the groove 13, i.e. its opening on the side of the front face 120 of the outer flange 12, to a rear face 132 of the groove 13, i.e. its opening on the side of the rear face 121 of the outer flange 12. This ventilation direction DV, visible more particularly in [Fig. 2], is finally defined by the orientation of the drilling relative to the plane formed by the front face 120 and the rear face 121 of the outer flange 12.

[0054] Indeed, in order to increase the exchange surface between the brake disc 1 and the air circulating around it, the invention cleverly provides for increasing the surface area of ​​the lateral edges of each groove 13. In known brake discs, the holes made on the outer flange 12 are made perpendicular to the surface of the brake disc 1, for reasons of practicality and simplicity. In these cases known from the prior art, the depth of a hole is exactly equal to a thickness of the outer flange 12. Conversely, the invention provides for inclining this direction of drilling - the ventilation direction DV - so as to increase the depth of the groove 13 - measured along the ventilation direction DV - so that it is greater than the thickness of the outer flange 12, taken as the distance between the front face 120 and the rear face 121, along a direction parallel to the axis of rotation 01.

[0055] Thus, by increasing the depth of each groove 13, by inclining the drilling direction of said grooves 13, it is then possible to increase the surface area of ​​the peripheral edges of the grooves 13 and, in doing so, to increase the exchange surface area between the brake disc 1 and the air. The transparency of [Fig. 3] makes it possible to visualize the depth of the grooves 13, which is clearly seen as being much greater than the thickness of the outer flange 12 of the brake disc 1 according to the invention. In the exemplary embodiment illustrated in the FIGURES, the ventilation direction DV is inclined at a non-zero angle relative to an axial direction taken parallel to the axis of rotation 01.In particular, the inclination of the grooves 13 is at least greater than 10°, and preferably between 40° and 50°, making it possible to offer an exchange surface - for each groove 13 - of the order of double that which would be offered by an equivalent groove 13 with a ventilation direction DV parallel to the axis of rotation 01.

[0056] On this essential principle of the invention, the shape and arrangement of the grooves 13 along the outer flange 12 can be arbitrary. In particular, in the embodiment shown in the FIGURES, the grooves 13 are angularly regularly distributed around the axis of rotation 01, and they extend radially from an inner region of the outer flange 12 - proximal to the inner hub 11 - towards an outer peripheral edge of the outer flange 12. Furthermore, the grooves 13 are curved and arranged in a helical shape. This advantageous configuration makes it possible to optimize the cooling of the brake disc 1 and to make it more homogeneous.

[0057] The ventilation direction DV can be identical to all the given grooves 13 of the brake disc 1. This configuration offers the advantage of simplicity and reduces both manufacturing times and associated costs. However, to optimize the circulation of air in the brake disc 1 and through the grooves 13, it is advantageous for the ventilation direction DV to pivot around the axis of rotation 01 for each groove 13. Thus, if the grooves 13 wind around the axis of rotation 01 in a clockwise direction, it is advantageous for the ventilation direction DV to also pivot clockwise between two consecutive grooves 13. Of course, if the grooves 13 wind around the axis of rotation 01 in a counterclockwise direction, then the ventilation direction DV also pivots counterclockwise between two consecutive grooves 13.

[0058] Generally speaking, the ventilation direction DV pivots around the axis of rotation 01 by an angle equal to the angular distance separating two consecutive grooves 13, relative to the axis of rotation 01.

[0059] In summary, the invention relates to a brake disc 1 for a motor vehicle, the brake disc 1 comprising an inner hub 11 intended to be coupled to a wheel hub, an outer flange 12 extending radially around the inner hub 11, the outer flange 12 forming a friction surface intended to collaborate with a complementary clamping member of the brake disc 1, a ventilation device configured to facilitate the cooling of the outer flange 12, the ventilation device comprising a plurality of grooves 13 extending along the outer flange 12, each groove 13 opening on either side of the outer flange 12 relative to an axis of rotation 01 of the disc brake. According to the invention, each groove 13 has an air flow direction inclined relative to the axis of rotation 01, so that the ventilation direction DV forms a non-zero angle with the axis of rotation 01.

[0060] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention. In particular, the different characteristics, forms, variants and embodiments of the invention can be associated with each other in various combinations insofar as they are not incompatible or mutually exclusive. In particular, all the variants and embodiments described above can be combined with each other.

Claims

Claims

1. Brake disc (1) for a motor vehicle, the brake disc (1) comprising: - an inner hub (11) intended to be coupled to a wheel hub; - an outer flange (12) extending radially around the inner hub (11), the outer flange (12) forming a friction surface intended to collaborate with a complementary clamping member of the brake disc (1); - a ventilation device for the brake disc (1), the ventilation device being configured to facilitate the cooling of the outer flange (12) when the brake disc (1) is in use, the ventilation device comprising a plurality of grooves (13) extending along the outer flange (12), each groove (13) opening on either side of the outer flange (12) relative to an axis of rotation (01) of the disc brake; characterized in that each groove (13) has an air flow direction inclined relative to the axis of rotation (01).

2. Brake disc (1) according to the preceding claim, in which each groove (13) is axially delimited by a front face (131) and a rear face (132) located respectively on a front face (120) and a rear face (121) of the outer flange (12), the front face (131) of a groove (13) being axially offset relative to the rear face (132) of said groove (13).

3. Brake disc (1) according to any one of the preceding claims, wherein a ventilation direction (DV) of each groove (13) extends secantly relative to the rotation axis (01).

4. Brake disc (1) according to the preceding claim, wherein a depth of the groove (13), taken along the ventilation direction (DV) and between the front face (120) and the rear face (121) of the outer flange (12), is greater than a thickness of the outer flange (12) measured along the axis of rotation (01).

5. Brake disc (1) according to any one of claims 3 or 4, in which the ventilation direction (DV) has an angle of between 40° and 50° relative to a front face (120) and / or a rear face (121) of the outer flange (12).

6. Brake disc (1) according to any one of claims 3 to 5, in which the ventilation direction (DV) forms an angle of between 40° and 50° relative to the axis of rotation (01) of the brake disc (1).

7. A brake disc (1) according to any preceding claim, wherein each groove (13) has an oblong shape.

8. A brake disc (1) according to any preceding claim, wherein a width of the groove (13) is between 1 mm and 5 mm.

9. Braking system for a motor vehicle, the braking system comprising a brake disc (1) according to any one of the preceding claims and a clamping member configured to be pressed against the outer flange (12) of the brake disc (1).

10. Motor vehicle comprising a braking system according to the preceding claim.

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