Disc for ventilated disc brake
By designing the annular brake belt and the annular ventilation part in the disc of the ventilated disc brake, and adding multiple ventilation channels in the circumferential distribution in the ventilation part, the problem of insufficient cooling efficiency of the brake belt in the prior art is solved, and a higher heat exchange power and a lower working temperature are achieved.
Patent Information
- Application Number
- CN202380073329.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-10-17
- Filing Date
- 2023-10-12
- Publication Date
- 2025-05-27
AI Technical Summary
The discs of existing ventilated disc brakes cannot ensure optimal cooling efficiency for the brake belt, especially as the demand for automobiles is increasing, the car is getting heavier and faster, the brake system must dissipate higher thermal power.
A disk for a ventilated disc brake is designed, and the disc includes an annular brake belt and an annular ventilation part. The brake belt consists of an overlapping carbon fiber layer oriented parallel along the axis of rotation. The ventilation part includes a plurality of ventilation channels distributed in the circumferential direction. The ventilation channels are connected to the outer radial edge and compartment through a specific opening structure, increasing the cooling capacity of the brake belt.
By significantly increasing the heat exchange surface, higher heat exchange power values are achieved, resulting in lower operating temperatures, and with the same size, the mass of the brake disc is reduced by 3% and the wear of the brake pad is less.
Smart Images
Figure CN120051402A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a disc for a ventilated disc brake, the disc comprising a plurality of layers of carbon fiber. More specifically, the present invention relates to a disc for a ventilated disc brake, the disc comprising a brake band having a high cooling efficiency. Background Art
[0002] The use of discs for disc brakes made of carbon-based materials, so-called "carbon-carbon" or "C / C", is known. These composite materials consist of a carbon matrix in which carbon reinforcing fibers are provided.
[0003] Discs made of "C / C" material are obtained by a process that includes overlapping layers or sheets of carbon fiber in the form of woven fabric and / or non-woven fabric to form a so-called carbonaceous "preform", adding resin, followed by heat treatment, and carbon densification treatment. The carbon densification treatment increases the density of the material, enabling the material to have sufficient mechanical, thermal, and tribological properties. For example, the density can be increased by 2 to 6 times.
[0004] As a friction material, "C / C" material requires a relatively high application temperature, which makes discs made of "C / C" material particularly suitable for the racing field and aviation applications.
[0005] As is well known, the disc includes a brake band that is provided with two opposite braking surfaces for cooperating with a pair of opposing pads of a brake caliper. The brake caliper hydraulically driven by a cylinder / piston assembly presses the pads against the braking surfaces of the brake band. Thus, the braking action is generated by the frictional force between the pads and the braking surfaces of the brake band of the disc.
[0006] The friction of the pads against the brake band of the disc causes the kinetic energy of the object being braked to be converted into heat and dissipated, resulting in an increase in the temperature of the disc, especially at the braking surfaces. Therefore, the brake band needs to have as high a cooling efficiency as possible.
[0007] For this reason, in a ventilated disc, the brake band is formed by two plate-like members, the outer surfaces of the two plate-like members defining two braking surfaces, while the inner surfaces define a part of the disc including ventilation channels for cooling the brake disc, and the ventilation channels are also referred to as ventilation parts.
[0008] However, the ventilation solutions proposed so far cannot ensure optimal cooling efficiency, especially considering the growing demands of automobiles, which are becoming heavier and faster, resulting in the need for the braking system to dissipate higher thermal power.
[0009] Therefore, the fundamental problem of the present invention is to provide a disc for a ventilated disc brake that can provide optimal cooling efficiency for the brake band, that is, can exchange a higher thermal power, thereby ensuring a lower operating temperature. Summary of the Invention
[0010] The above problem is solved by a disc for a ventilated disc brake as outlined in the appended claims, the definition of which forms part of this specification.
[0011] In particular, an object of the present invention is a disc for a ventilated disc brake, the disc comprising an annular brake band and an annular ventilation part of the disc, wherein,
[0012] the brake band and the ventilation part comprise a plurality of layers of carbon fiber stacked along an overlapping axis oriented parallel to the rotation axis of the disc,
[0013] the brake band comprises two plate-like members that are coaxial and spaced apart from each other in the axial direction, thereby defining the ventilation part, the axial direction being coincident with or parallel to the rotation axis of the disc, and the plate-like members comprise two outer surfaces that define opposite braking surfaces,
[0014] the ventilation part comprises an outer radial edge, an inner radial edge, and a plurality of protrusions that protrude radially from the inner radial edge towards the rotation axis, wherein the protrusions define a plurality of compartments, each compartment being positioned between one protrusion and another protrusion,
[0015] The disc is characterized in that:
[0016] the ventilation part comprises a plurality of ventilation channels circumferentially distributed in at least two rows, the ventilation channels being adapted to ensure the flow of cooling fluid between the two plate-like members,
[0017] the ventilation channels lead to the outer radial edge of the ventilation part through corresponding first openings and to the compartments through corresponding second openings, the first openings being circumferentially distributed in at least two rows forming corresponding circumferential parts,
[0018] the ventilation channels are grouped into corresponding clusters, and the ventilation channels of each cluster lead to the same compartment through the second openings.
[0019] Compared with existing discs with ventilation channels of different distributions, the specific distribution of the ventilation channels within the ventilation portion of the disc of the present invention imparts to the disc of the present invention an increased cooling capacity of the brake band, i.e., the arrangement structure in which the ventilation channels of the disc of the present invention are arranged axially in at least two rows and the ventilation channels lead to the outer diameter edge of the ventilation portion through corresponding openings, and the corresponding openings are distributed circumferentially in at least two rows to form corresponding circumferential portions imparts to the disc of the present invention an increased cooling capacity of the brake band, while the ventilation channels of the existing discs are specifically located in a single row.
[0020] In fact, it has surprisingly been found that by significantly increasing the heat exchange surface, higher values of the exchanged heat power can be obtained, which in turn advantageously results in a lower operating temperature.
[0021] To better understand the present invention and to recognize its advantages, some non-limiting exemplary embodiments of the present invention will be described hereinafter with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 is an isometric view of a disc for a disc brake as viewed from the brake band side facing the vehicle according to an embodiment of the present invention, which shows the brake band and the ventilation portion of the disc, and more specifically shows the plate-like member of the brake band.
[0023] Figure 2 is an isometric view of a disc for a disc brake as viewed from the brake band side facing the wheel according to an embodiment of the present invention, which shows the brake band and the ventilation portion of the disc, and more specifically shows a plate-like member opposite to the Figure 1 plate-like member visible in
[0024] Figure 3 is a side view of a disc for a disc brake according to an embodiment of the present invention, which shows the plate-like member of the brake band and the outer radial edge of the ventilation portion.
[0025] Figure 3A is Figure 3 an enlarged view of the dashed area in
[0026] Figure 4 is a cross-sectional view taken along the Figure 3 axis D-D in
[0027] Figure 4A is Figure 4 an enlarged view of the cluster of ventilation channels highlighted in
[0028] Figure 5 is a front view of a disc for a disc brake as viewed from the brake band side facing the vehicle according to an embodiment of the present invention, which shows the brake band and the ventilation portion of the disc, and more specifically shows the plate-like member of the brake band.
[0029] Figure 6 is a front view of a disc of a disc brake as viewed from the brake band side facing the wheel according to an embodiment of the present invention, which shows the brake band and the ventilation part of the disc, and more specifically, shows a plate-like member opposite to the Figure 5 plate-like member visible in
[0030] Figure 7 shows a perspective view of a set of overlapping carbon layers capable of being used to manufacture a disc for a disc brake according to an embodiment of the present invention.
[0031] Figure 8 and Figure 9 schematically show a radial section and a transverse section of a carbon layer capable of being used to manufacture a disc for a disc brake according to an embodiment of the present invention, respectively. Detailed Description
[0032] Referring to the drawings, a disc for a disc brake (also referred to as a "brake disc" in the present application) is generally designated by reference numeral 1, and in particular, the disc is a ventilated brake disc.
[0033] The brake disc 1 is adapted to rotate about a rotational axis X-X. The brake disc 1 defines an axial direction A-A that is coincident with or parallel to the rotational axis X-X, a radial direction R-R that is orthogonal to the axial direction A-A, and a tangential or circumferential direction C-C that is orthogonal to both the axial direction A-A and the radial direction R-R.
[0034] The brake disc 1 includes an annular brake band 2 (more simply referred to as a "brake band" in the present application), and the annular brake band 2 in turn includes a first plate-like member 3 and a second plate-like member 4 arranged side by side. The first plate-like member 3 and the second plate-like member 4 are coaxial with the same axial direction A-A and are spaced apart from each other in the axial direction A-A, thereby defining at least one annular ventilation part 5 (more simply referred to as a "ventilation part" in the present application).
[0035] The first plate-like member 3 is defined by an outer surface 6 and an inner surface 6' (as Figure 3A shown). Similarly, the second plate-like member 4 is defined by an outer surface 7 and an inner surface 7' (as Figure 3A shown). The surfaces 6, 6', 7, 7' extend in a plane orthogonal to the rotational axis X-X.
[0036] The outer surfaces 6, 7 define opposite braking surfaces for cooperating with a pair of brake pads (not shown) to apply a braking action, while the inner surfaces 6', 7' define an area for the aforementioned annular ventilation part 5 to extend.
[0037] The ventilation part 5 includes an outer radial edge 8 and an inner radial edge 9 (the inner radial edge 9 is as Figure 5 shown).
[0038] A plurality of connection protrusions 10 adapted to be associated with a bell-shaped member (not shown) of the disc project radially from the inner radial edge 9 in the radial direction R-R towards the rotation axis X-X. The bell-shaped member of the disc is adapted to be operatively connected to the wheel.
[0039] The protrusions 10 define a plurality of compartments 11 or recesses 11 located between one protrusion and the next.
[0040] According to a preferred embodiment, each of the protrusions 10 includes a wall 12 having a profile of an arcuate portion with a circumferential portion, as shown in the drawings (for example, see Figure 5 ).
[0041] The wall 12 extends circumferentially. The walls 12 separated by the above-mentioned compartments 11 will form a radial edge 13 coaxial with the radial edges 8, 9 of the ventilation part 5 when the walls 12 are joined together (as Figure 5 shown).
[0042] According to a preferred embodiment, the compartment 11 has the following profile: the profile has a top portion with a semi-circular, parabolic or oval profile, as shown in the drawings. This means that the protrusion 10 defining the compartment 11 has two curved side walls 14; for example, the side walls 14 have a semi-dome profile with a semi-circular, parabolic or oval profile. More particularly, one side wall of the side walls 14 of the protrusion 10 and the adjacent side wall 14 of the next protrusion 10 form one of the compartments 11 in the compartment 11 (for example, as Figure 5 shown).
[0043] The brake band 2 includes a vehicle-facing side adapted to face the vehicle and an axially opposite side to the vehicle-facing side and adapted to face the wheel (or wheel-facing side). The bell-shaped member is associated with the wheel-facing side of the brake band 2.
[0044] Figure 1 and Figure 5 show the brake disc 1 as seen from the vehicle-facing side; Figure 2 and Figure 6 show the brake disc 1 as seen from the wheel-facing side.
[0045] The brake band 2 includes the first plate-like member 3 located on the vehicle-facing side and the second plate-like member 4 located on the wheel-facing side.
[0046] Advantageously, the extension of the first plate-like member 3 in the radial direction R-R and towards the rotation axis X-X is smaller than that of the second plate-like member 4. Advantageously, the protrusions 10 and the corresponding compartments 11 protrude in the radial direction R-R from the first plate-like member 3 and not from the second plate-like member 4 (e.g., as Figure 1 shown). More particularly, the protrusions 10 and the corresponding compartments 11 are covered by the second plate-like member 4 in the R-R direction (e.g., as Figure 2 shown), but not by the first plate-like member 3.
[0047] Preferably, the second plate-like member 4 includes a first annular portion 4a and an innermost second annular portion 4b, e.g., as Figure 2 shown.
[0048] The portion 4a includes an outer surface 7a that serves as a braking surface, i.e., the outer surface 7a cooperates with the brake pad; the portion 4b includes an outer surface 7b that is not part of the braking surface.
[0049] Preferably, the outer surface 6 of the first plate-like member 3 corresponds to the braking surface, i.e., the outer surface 6 as a whole cooperates with the brake pad.
[0050] Preferably, the first annular portion 4a of the second plate-like member 4 has the same extension or substantially the same extension as the first plate-like member 3. This means that, preferably, the two opposite braking surfaces have the same or substantially the same extension.
[0051] Advantageously, the portion 4b of the second plate-like member 4 includes a plurality of seats 15 arranged circumferentially. Similarly, each protrusion 10 includes a seat 16 that corresponds to the seat 15 formed in the portion 4b of the second plate-like member 4. Therefore, preferably, the number of seats 15 included in the portion 4b is equal to the number of protrusions 10. The seats 15 and 16 are adapted to accommodate the respective means for connecting the bell-shaped member to the disc by the brake band 2. Such means are known in the art and will not be described further in this patent application.
[0052] The ventilation portion 5 includes a plurality of ventilation channels, generally denoted by the reference numeral 17, which are adapted to ensure the flow of the cooling fluid between the two plate-like members 3, 4. In the embodiment shown in the drawings, the ventilation channels 17 are distributed in two rows 37, 47 circumferentially, as Figures 1 to 3 shown. According to other embodiments not shown, the ventilation portion may include a plurality of ventilation channels distributed in more than two rows, e.g., distributed in three rows, distributed in four rows, or distributed in five rows circumferentially.
[0053] The following description relates to an embodiment shown in the drawings, in which the ventilation channels are circumferentially distributed in two rows; however, the following description can equally be applied to embodiments in which the ventilation channels are circumferentially distributed in more than two rows.
[0054] Preferably, the ventilation channels 17 in row 37 are aligned with the ventilation channels 17 in the adjacent row 47 along the axial direction A-A, as shown in the drawings. The following description will refer to this preferred embodiment, but the following description should not be regarded as limiting the object of the present invention. Alternative embodiments may provide that the ventilation channels 17 in row 37 are angularly offset with respect to the ventilation channels 17 in the adjacent row 47.
[0055] The ventilation channels 17 lead to the outer radial edge 8 of the ventilation section 5 through corresponding first openings 18 and lead to the aforementioned compartment 11 through corresponding second openings 19.
[0056] In the embodiment shown in the drawings, the first openings 18 are equidistant from each other and are circumferentially distributed in two rows forming two circumferential portions. According to other embodiments not shown, the first openings 18 are not equidistant from each other.
[0057] Cooling fluid (preferably air) enters through the second openings 19 and exits through the first openings 18. Thus, the compartment 11 defines an inlet surface for the cooling fluid, while the outer radial edge 8 of the ventilation section 5 defines an outlet surface for the cooling fluid.
[0058] In the drawings, particularly in Figures 1 to 3 is shown a machining port denoted by the reference numeral 30. The machining port is mainly used to hold the brake disc 1 stationary on a dedicated machine during the application of a protective layer such as silicon carbide, for example, by known application methods, including chemical vapor deposition (CVD), metal deposition, or laser deposition.
[0059] The ventilation channels 17 are divided into clusters 20. The ventilation channels 17 belonging to the same cluster 20 lead to the same compartment 11 through the second openings 19.
[0060] Each cluster in the cluster 20 may include 3 to 14 ventilation channels 17 per row. Preferably, each cluster in the cluster 20 may include 4 to 12 ventilation channels 17 per row. Alternatively, each cluster in the cluster 20 may include 4 to 10 ventilation channels 17 per row. For example, each cluster in the cluster 20 may include 4, 5, 6, 7, 8, 9, or 10 ventilation channels 17 per row. In the following description, although not repeated every time, when referring to the ventilation channels of the same cluster, it always refers to the "per row" ventilation channels of the same cluster. Therefore, when there are two rows, the total number of ventilation channels in each cluster will be twice the number shown each time; when there are three rows, the number of ventilation channels in each cluster will be three times the number shown each time, and so on.
[0061] Preferably, the outermost peripheral ventilation channels 17 of each cluster 20 have a larger internal ventilation area than the innermost ventilation channels 17, that is, the ventilation channels forming the ends of each cluster 20 or the ventilation channels adjacent to the ends have a larger internal ventilation area than the innermost ventilation channels 17.
[0062] More preferably, the surface extension of the first opening 18 of the outermost peripheral ventilation channels 17 of each cluster 20 is larger than the surface extension of the first opening 18 of the innermost ventilation channels 17 of each cluster 20. Preferably, the extension of the first opening 18 of the outermost peripheral ventilation channels 17 of each cluster 20 in the circumferential direction C-C (also referred to as the "circumferential width") is larger than the extension of the first opening 18 of the innermost ventilation channels 17 of each cluster 20 in the circumferential direction. Preferably, the ventilation channels 17 belonging to the same cluster 20 lead to the compartment 11 through the following second opening 19: the second opening 19 has the same surface extension.
[0063] Surprisingly, the above geometric configuration of the ventilation channels of each cluster ensures greater structural strength and better heat transfer.
[0064] According to the preferred embodiment shown in the drawings, each cluster in the cluster 20 includes 4 ventilation channels 17. More specifically, each cluster in the cluster 20 includes a first peripheral ventilation channel 17a, a second peripheral ventilation channel 17b, and two additional internal ventilation channels 17c, 17d arranged between the peripheral ventilation channels 17a and 17b.
[0065] Preferably, the internal ventilation areas of the peripheral ventilation channels 17a, 17b are larger than those of the internal ventilation channels 17c, 17d. More preferably, the peripheral ventilation channels 17a, 17b lead to the outer radial edge 8 of the ventilation part 5 through the corresponding first openings 18 below: the surface extension of the first opening 18 of the peripheral ventilation channels 17a, 17b is larger than that of the first opening 18 of the internal ventilation channels 17c, 17d. Preferably, the extension of the first opening 18 of the peripheral ventilation channels 17a, 17b in the circumferential direction is larger than that of the first opening 18 of the internal ventilation channels 17c, 17d in the circumferential direction. Preferably, all four ventilation channels 17a, 17b, 17c, 17d lead to the compartment 11 through the second openings 19 having the same surface extension.
[0066] According to an embodiment not shown, each cluster 20 includes five ventilation channels 17. According to this embodiment, preferably, each cluster 20 includes two peripheral ventilation channels and three internal ventilation channels arranged between the two peripheral ventilation channels. Preferably, the internal ventilation areas of the two peripheral ventilation channels are larger than those of the three internal ventilation channels, and thus lead to the outer radial edge 8 of the ventilation part 5 through the corresponding first openings 18 below: the surface extension of the first opening 18 of the peripheral ventilation channels is larger than that of the first opening 18 of the internal ventilation channels. Preferably, the extension of the first opening 18 of the peripheral ventilation channels in the circumferential direction is larger than that of the first opening 18 of the internal ventilation channels in the circumferential direction.
[0067] According to another embodiment not shown, each cluster 20 includes ten ventilation channels 17. According to this embodiment, preferably, each cluster 20 includes two groups of peripheral ventilation channels, each group of peripheral ventilation channels including: two ventilation channels, a total of four peripheral ventilation channels; two groups of internal ventilation channels, each group of internal ventilation channels being adjacent to one of the groups of peripheral ventilation channels, and each group of internal ventilation channels including two ventilation channels, a total of four internal ventilation channels; two or more internal ventilation channels arranged between the two groups of internal ventilation channels. Preferably, the internal ventilation areas of the four peripheral ventilation channels are larger than those of the four internal ventilation channels, and the internal ventilation areas of the four internal ventilation channels are in turn larger than those of the two or more internal ventilation channels.
[0068] According to another embodiment (not shown), each cluster 20 includes twelve ventilation channels 17. According to this embodiment, preferably, each cluster 20 includes two sets of peripheral ventilation channels, each set of peripheral ventilation channels includes two ventilation channels, for a total of four peripheral ventilation channels; two sets of internal ventilation channels, each set of internal ventilation channels is adjacent to one of the sets of peripheral ventilation channels, and each set of internal ventilation channels includes two ventilation channels, for a total of four internal ventilation channels; two or more sets of internal ventilation channels arranged between the two sets of internal ventilation channels, each set of internal ventilation channels includes two ventilation channels, for a total of four innermost ventilation channels. Preferably, the internal ventilation area of the four peripheral ventilation channels is greater than the internal ventilation area of the four internal ventilation channels, and the internal ventilation area of the four internal ventilation channels is greater than the internal ventilation area of the four innermost ventilation channels.
[0069] Preferably, the first opening 18 of the ventilation channel 17 has a groove shape, as shown in the accompanying drawings. The term "groove" refers to a geometric figure formed by two arcs connected to each other by a straight line. Alternatively, the shape of the first opening 18 may be oval or substantially oval, or circular or substantially circular.
[0070] Preferably, the shape of the second opening 19 of the ventilation channel 17 is circular or substantially circular, or oval or substantially oval.
[0071] In the embodiment where the shape of the first opening is a groove shape, oval or substantially oval, preferably, according to the above definition, the extension of the first opening 18 of the outermost ventilation channel 17 of each cluster 20 in the circumferential direction C-C is larger than the extension of the first opening 18 of the innermost ventilation channel 17 of each cluster 20 in the circumferential direction C-C, and the extension of the first opening 18 of the outermost ventilation channel 17 of each cluster 20 in the axial direction A-A is the same as the extension of the first opening 18 of the innermost ventilation channel 17 of each cluster 20 in the axial direction A-A. For example, in the above embodiment where each cluster 20 includes four ventilation channels 17, the peripheral ventilation channels 17a, 17b lead to the outer radial edge 8 of the ventilation part 5 through the corresponding first openings 18: the circumferential width of the first openings 18 of the peripheral ventilation channels 17a, 17b is larger than the circumferential width of the first openings 18 of the internal ventilation channels 17c, 17d, and the extension of the first openings 18 of the peripheral ventilation channels 17a, 17b in the axial direction is the same as the first openings 18 of the internal ventilation channels 17c, 17d in the axial direction, as shown in the accompanying drawings.
[0072] According to Figure 4 and 4A the preferred embodiment shown, the cross-section of each ventilation channel 17 in a plane perpendicular to the rotation axis X-X is defined by the following:
[0073] An arcuate portion 21 of a circumferential portion at the outer diameter edge 8 of the ventilation portion 5;
[0074] Two straight lines 22, 23 converging away from the outer radial edge 8, the straight lines 22, 23 being defined by two first ends 21', 21'' and two second ends 24, 25, the two first ends 21', 21'' corresponding to the ends of the arcuate portion 21 of the circumferential portion, and
[0075] Two parallel or substantially parallel straight lines 26, 27, the straight lines 26, 27 extending from the second ends 24, 25 until one of the compartments 11.
[0076] In this embodiment, the ventilation channel 17 advantageously has a funnel shape or a similar shape.
[0077] According to an alternative embodiment not shown in the drawings, each ventilation channel 17 is defined in a plane perpendicular to the rotation axis X-X by:
[0078] An arcuate portion of a circumferential portion at the outer diameter edge 8 of the ventilation portion 5, and
[0079] Two straight lines converging away from the outer radial edge 8, the straight lines being defined by two ends corresponding to the ends of the arcuate portion of the circumferential portion and two opposite ends corresponding to one of the compartments 11.
[0080] Preferably, each cluster 20 in the above-mentioned cluster 20 has a circumferential width in the range of about 25° to about 60°, preferably, each cluster 20 in the above-mentioned cluster 20 has a circumferential width between about 30° and about 45°, more preferably, the circumferential width of each cluster 20 in the above-mentioned cluster 20 is about 36°. More particularly, the angle is defined by two semi-radial lines (as Figure 4 shown), the two semi-radial lines intersecting at the intersection of the rotation axis X-X and the axis oriented along the radial direction R-R and passing through the centers of two seats 16 provided in two consecutive protrusions 10.
[0081] Preferably, the number of clusters 20 included in the ventilation portion 5 is between 6 and 14, preferably, the number of clusters 20 included in the ventilation portion 5 is between 8 and 12. Advantageously, the number of clusters 20 corresponds to the number of protrusions 10 and the number of corresponding compartments 11, and thus corresponds to the number of accessories of the bell-shaped member.
[0082] According to the embodiment shown in the drawings, the ventilation portion 5 includes ten clusters 20, each cluster defining an angle of 36° or about 36°, and thus includes ten protrusions 10 and ten compartments 11.
[0083] According to a preferred embodiment, each cluster 20 includes four ventilation channels and is defined by an angle of 36° or approximately 36°. According to this embodiment, preferably, the peripheral ventilation channels 17a, 17b are defined by an angle between 12° and 15°, for example, defined as an angle of 14.5°, and the internal ventilation channels 17c, 17d are defined by a smaller angle between 8° and 11°, for example, defined as an angle of 10°. More specifically, the angle defined by each ventilation channel (i.e., the circumferential width of each ventilation channel) is defined by the corresponding converging straight lines 22, 23.
[0084] Preferably, the brake disc 1 according to the present invention further includes a plurality of axial ventilation channels 28. The axial ventilation channels 28 lead to the braking surfaces of the first plate-like member 3 and the second plate-like member 4 through corresponding openings 29.
[0085] The axial ventilation channels 28 are adapted to ensure that the flow of the cooling fluid is substantially orthogonal to the flow of the cooling fluid flowing in the ventilation channels 17 distributed in the ventilation portion 5.
[0086] The axial ventilation channels 28 put the ventilation channels 17 in fluid communication with the braking surfaces.
[0087] According to a preferred embodiment, the brake disc 1 includes a plurality of layers 100, 101, 102, 103 of carbon fiber, which are stacked along an overlapping axis also called the structural axis, and this overlapping axis is oriented parallel to the rotation axis X-X of the disc 1. For the sake of description, Figure 7 four layers 100, 101, 102, 103 are shown, but the number of these layers is only illustrative and does not constitute a limitation.
[0088] In Figure 7 the example shown, the respective layers 100, 101, 102, 103 of carbon fiber include a plurality of radial segments 104 and transverse segments 105, and the radial segments 104 and the transverse segments 105 are placed side by side and joined together to form the layer. Each radial segment 104 is adjacent to and joined to the transverse segment 105 on both sides, and each transverse segment 105 is adjacent to and joined to the radial segment 104 on both sides, thereby forming alternating radial segments 104 and transverse segments 105 in the respective layers 100, 101, 102, 103.
[0089] The radial segments 104 are segments in which the carbon fiber is mainly oriented in the radial direction R relative to the overlapping axis or is substantially parallel to the radial direction R. The transverse segments 105 are segments in which the carbon fiber is mainly oriented in a direction I intersecting the radial direction. In this regard, Figure 8 and Figure 9The illustrations therein respectively show the orientation of carbon fibers in the radial direction and the transverse direction on the corresponding sections 104 and 105.
[0090] In a preferred embodiment, the intersecting direction I is orthogonal or substantially orthogonal to the radial direction R.
[0091] In the following description, unless otherwise specified, the terms "radial", "axial", "angularly", "circumferentially" shall be understood with respect to the overlapping axis.
[0092] Advantageously, at least a part of the sections 104, 105 is in the form of an annular sector or a coronal annular arch, as Figure 7 shown.
[0093] Preferably, the circumferential width of the annular sector or the coronal annular arch is included in the range of 60° to 90°, preferably, the circumferential width of the annular sector or the coronal annular arch is included in the range of 60° to 80°, preferably, the circumferential width of the annular sector or the coronal annular arch is included in the range of 65° to 72°, for example, the circumferential width of the annular sector or the coronal annular arch is about 68°.
[0094] In an embodiment of the present invention, all the sections 104, 105 have substantially the same shape. Preferably, all the sections 104, 105 have the same circumferential width.
[0095] In a preferred embodiment, each section mainly comprises or only comprises unidirectional carbon fibers, and the unidirectional carbon fibers are arranged along the radial direction R or the intersecting direction I according to whether the unidirectional carbon fibers are the radial section 104 or the transverse section 105.
[0096] In a preferred embodiment, with respect to the overlapping axis, the sections of the layer 100 are angularly offset with respect to the sections of the adjacent layer 101, so that the joint areas 106 between the sections do not overlap in the thickness of the brake disc 1.
[0097] In an embodiment of the present invention, with respect to the overlapping axis, each radial section 104 of layer 100 partially overlaps with the radial section 104 of the adjacent layer 101 and partially overlaps with the transverse section 105 of the adjacent layer 101. According to this embodiment, the overlapping portion of each radial section 104 of layer 100 with the radial section 104 of the adjacent layer 101 is equal to 5% to 50% of the circumferential width of the radial section. Preferably, the overlapping portion of each radial section 104 of layer 100 with the radial section 104 of the adjacent layer 101 is equal to 10% to 40% or 15% to 35% of the circumferential width of the radial section, and the overlapping portion of each radial section 104 of layer 100 with the transverse section 105 of the adjacent layer 101 is equal to 50% to 95%. Preferably, the overlapping portion of each radial section 104 of layer 100 with the transverse section 105 of the adjacent layer 101 is equal to 60% to 90% or 65% to 85%.
[0098] Similarly, in an embodiment of the present invention, with respect to the overlapping axis, each transverse section 105 of layer 100 partially overlaps with the transverse section 105 of the adjacent layer 101 and partially overlaps with the radial section 104 of the adjacent layer 101. According to this embodiment, the overlapping portion of each transverse section 105 of layer 100 with the transverse section 105 of the adjacent layer 100 is equal to 5% to 50% of the circumferential width of the transverse section 105. Preferably, the overlapping portion of each transverse section 105 of layer 100 with the transverse section 105 of the adjacent layer 100 is equal to 10% to 40% or 15% to 35% of the circumferential width of the transverse section 105, and the overlapping portion of each transverse section 105 of layer 100 with the radial section 104 of the adjacent layer 101 is equal to 50% to 95%. Preferably, the overlapping portion of each transverse section 105 of layer 100 with the radial section 104 of the adjacent layer 101 is equal to 60% to 90% or 65% to 85%.
[0099] In an embodiment (not shown), at least one section of layer 100 may partially overlap with at least one other section arranged side by side with it in the circumferential direction.
[0100] Advantageously, in each of the layers 100, 101, 102, 103, the number of radial sections 104 is equal to the number of transverse sections 105.
[0101] In an embodiment of the present invention, the sections 104, 105 are formed in a substantially continuous manner around the structural axis in a spiral extension on multiple layers 100, 101, 102, 103 of carbon fiber. In this case, the layers 100, 101, 102, 103 are represented by coil portions. According to this embodiment, preferably, the inclination of each coil portion with respect to the axis orthogonal to the structural axis is included in the range of 1° to 10°, preferably, the inclination of each coil portion with respect to the axis orthogonal to the structural axis is included in the range of 1° to 5°. For example, the inclination of each coil portion with respect to the axis orthogonal to the structural axis is about 1°.
[0102] In this specification, the terms "layer" and "coil portion" are generally used interchangeably. Therefore, when the sections 104, 105 extend to form a helical member, the layers 100, 101, 102, 103 should be understood as coil portions.
[0103] In a preferred embodiment, the number of layers 100, 101, 102, 103 or coil portions of carbon fiber is included in the range between 10 and 50. Preferably, the number of layers 100, 101, 102, 103 or coil portions of carbon fiber is included in the range between 18 and 40. For example, the number of layers 100, 101, 102, 103 or coil portions of carbon fiber is included in the range between 20 and 35 or between 24 and 30. In a specific embodiment, the number of layers or coil portions is between 21 and 26.
[0104] By way of example only, the thickness of each of the layers 100, 101, 102, 103 of carbon fiber can be between 0.5 mm and 3 mm. For example, the thickness of each of the layers 100, 101, 102, 103 of carbon fiber can be about 1.25 mm or 1.5 mm.
[0105] By way of example only, the thickness of the brake disc 1 of the present invention can be equal to or greater than about 5 mm. For example, the thickness of the brake disc 1 of the present invention can be equal to or greater than about 25 mm. For example, the thickness of the brake disc 1 of the present invention can be between about 25 mm and about 300 mm. For example, the thickness of the brake disc 1 of the present invention can be 28 mm, 32 mm, 34 mm, 38 mm or 40 mm.
[0106] In an embodiment of the present invention, at least a part of the carbon fiber is derived from oxidized polyacrylonitrile fiber. Preferably, all carbon fibers are derived from oxidized polyacrylonitrile fiber.
[0107] In a preferred embodiment, the brake disc 1 includes a carbonaceous matrix in which at least a part of the carbon fiber is embedded. The expression "carbonaceous matrix" means a matrix composed of at least 50% carbon.
[0108] In an embodiment of the present invention, the brake disc 1 comprises silicon carbide (SiC) and optionally silicon (Si). The silicon carbide (SiC) is obtained by reacting at least a part of the silicon (Si) infiltrated into the brake disc 1 with a part of the carbon (C) in the carbon fiber and / or the carbonaceous matrix of the brake disc 1. Preferably, the silicon carbide (SiC) is arranged as a bridging member between adjacent layers 100, 101, 102, 103 of carbon fibers.
[0109] Preferably, the residual porosity of the brake disc 1 is less than 5%, for example, the residual porosity of the brake disc 1 is equal to or less than 3%. Preferably, the value of the residual porosity is for the brake disc 1 including silicon carbide (SiC), specifically, it is obtained at the end of at least one step of infiltration with silicon (Si).
[0110] Advantageously, the minimum allowable thickness of the plate-like members 3, 4 of the brake disc 1 above (i.e., the minimum thickness of the plate-like members worn due to friction of the brake surface against the brake pads without structural failure of the brake disc; in other words, the thickness of the plate-like members worn at the end of the disc service life) is formed by three above-mentioned carbon fiber layers stacked along the overlapping axis, wherein each layer of carbon fiber is formed by a plurality of radial segments and transverse segments, and each radial segment alternates with the transverse segment. This means that the flexural strength of the plate-like members 3, 4 is ensured by the overlap of the three layers of carbon fibers.
[0111] In a preferred embodiment, the thickness of the brake disc 1 of the present invention is 34 mm or about 34 mm. More particularly, the thickness of each plate-like member 3, 4 at the beginning of its service life is 7 mm or about 7 mm, while the thickness of the ventilation part is 20 mm or about 20 mm.
[0112] The brake disc 1 as described above, in which each layer of carbon fiber is formed by a plurality of radial segments and transverse segments and each radial segment alternates with the transverse segment, can be manufactured by a method comprising the following steps:
[0113] a) Stacking a plurality of layers of carbon fiber or a precursor of the carbon fiber along the overlapping axis to form a multi-layer body, each layer of which is formed by a plurality of radial segments and transverse segments, wherein each radial segment is adjacent to and joined with transverse segments on both sides, and each transverse segment is adjacent to and joined with radial segments on both sides, thereby forming alternating radial segments and transverse segments in each layer. Optionally, the step a) further comprises a step of needling the stacked layers;
[0114] b) Subject the multi-layer body obtained in step (a) to thermal densification or thermochemical densification treatment. For example, subject the multi-layer body obtained in step (a) to CVD (Chemical Vapor Deposition), CVI (Chemical Vapor Infiltration), LPI (Liquid Polymer Infiltration), or PIP (Polymer Infiltration and Pyrolysis);
[0115] c) Optionally, infiltrate the material obtained in step b) with an infiltrant such as silicon (Si) or silicon carbide (SiC), preferably by means of a liquid silicon infiltration (LSI) process, during which the silicon is heated to a temperature above its melting temperature in order to melt and infiltrate into the above-mentioned material by capillary action.
[0116] Experimental section
[0117] Compare the following:
[0118] 1) The brake disc according to the present invention (hereinafter simply referred to as "brake disc 1") includes a ventilation portion in which ventilation channels are circumferentially distributed in two rows, and
[0119] 2) The brake disc belonging to the related art (hereinafter simply referred to as "brake disc 1C") includes a ventilation portion in which ventilation channels are circumferentially distributed in one row and lead to the outer diameter edge of the ventilation portion through circular or substantially circular openings to optimize the heat transfer surface.
[0120] More specifically, the brake disc 1 is as shown in the drawings, wherein each cluster 20 includes four ventilation channels 17 and has a circumferential width of 36°; wherein each ventilation channel 17 leads to the outer radial edge 8 of the ventilation portion 5 through a first opening 18 in the shape of a groove; and wherein the peripheral ventilation channels 17a, 17b lead to the outer radial edge 8 of the ventilation portion 5 through the following grooves 18: the extensions of the grooves 18 of the peripheral ventilation channels 17a, 17b in the circumferential direction are larger than the extensions of the grooves 18 of the internal ventilation channels 17c, 17d in the circumferential direction.
[0121] Both the brake disc 1 and the brake disc 1C to be compared have a diameter of 390 mm and a thickness of 34 mm.
[0122] It is found that the extension of the inlet surface of the cooling fluid in the ventilation channels of the brake disc 1 [mm 2 is approximately 22% larger than the extension of the inlet surface of the cooling fluid in the ventilation channels of the brake disc 1C [mm 2 .
[0123] It is found that the extension of the entire inner surface of the ventilation channels of the brake disc 1 [mm 2 is larger than the extension of the entire inner surface of the ventilation channels of the brake disc 1C [mm 2Approximately 75%.
[0124] It was found that the air flow rate [kg / s] in the ventilation channels of the brake disc 1 was 16.6% greater than the air flow rate in the ventilation channels of the brake disc 1C.
[0125] It was found that the heat transfer [W] carried out by the ventilation channels only in the ventilation part of the brake disc 1 was 38.8% greater than the heat transfer carried out by the ventilation channels of the brake disc 1C.
[0126] It was found that the total heat transfer [W] carried out by the brake disc 1 (therefore also taking into account the contribution of the axial ventilation channels) was 24.7% greater than the heat transfer carried out by the brake disc 1C.
[0127] It was found that the operating temperature of the brake disc 1 was 70 °C lower compared to the brake disc 1C.
[0128] In addition to the technical advantages in terms of enhancing heat transfer, the brake disc 1 was also found to be lighter, with a 3% reduction in mass in the case of the same dimensions. Moreover, the wear of the brake pads cooperating with this brake disc was also smaller.
[0129] It is obvious that only specific embodiments of the present invention are described herein. Those skilled in the art can make all necessary modifications to the brake discs of the disc brakes to adapt them to specific situations, but this does not depart from the scope of protection defined by the appended claims.
[0130] List of reference numerals
[0131] 1 Disc for a disc brake
[0132] 2 Brake band
[0133] 3 First plate-like member
[0134] 4 Second plate-like member
[0135] 4a First annular part of the second plate-like member
[0136] 4b Second annular part of the second plate-like member
[0137] 5 Ventilation part
[0138] 6 Outer surface of the first plate-like member
[0139] 6’ Inner surface of the first plate-like member
[0140] 7 Outer surface of the second plate-like member
[0141] 7’ Inner surface of the second plate-like member
[0142] 7a, 7b Outer surfaces of the parts 4a and 4b of the second plate-like member
[0143] 8 Outer radial edge of the ventilation part
[0144] 9 Inner radial edge of the ventilation part
[0145] 10 Connecting protrusion
[0146] 11 Compartment or recess
[0147] 12 Wall of the connecting protrusion arranged on the circumferential part
[0148] 13 Radial edge defined by wall 12
[0149] 14 Side wall of the connecting protrusion
[0150] 15 Seat formed in the second part 4b of the second plate-like member
[0151] 16 Seat formed in the connecting protrusion
[0152] 17 Ventilation channel
[0153] 37, 47 Exhaust of the ventilation channel
[0154] 17a, 17b Peripheral ventilation channels
[0155] 17c, 17d Inner ventilation channels
[0156] 18 First opening of the ventilation channel
[0157] 19 Second opening of the ventilation channel
[0158] 20 Cluster of ventilation channels
[0159] 21 Arc-shaped part of the circumferential part of the cross-section of the ventilation duct
[0160] 21’, 21” Ends of the arc-shaped part 21 of the circumferential part
[0161] 22, 23 Converging straight lines of the cross-section of the ventilation channel
[0162] 24, 25 Second ends of the straight lines 22, 23
[0163] 26, 27 Parallel straight lines of the cross-section of the ventilation channel
[0164] 28 Axial ventilation channel
[0165] 29 Opening of the axial ventilation channel
[0166] 30 Machining port
[0167] Each layer of carbon fiber from 100 to 103
[0168] 104 Radial section
[0169] 105 Transverse section
[0170] The joint area between the 106 radial section and the transverse section.
Claims
1. A disc (1) for a ventilated disc brake, said disc (1) comprising an annular braking band (2) and an annular ventilation portion (5) of the disc, wherein, the braking band (2) and the ventilation portion (5) comprise a plurality of layers (100, 101, 102, 103) of carbon fiber, and the plurality of layers of carbon fiber are stacked along an overlapping axis oriented in a manner parallel to the rotational axis (X-X) of the disc (1), the braking band (2) comprises two plate-like members (3, 4), the two plate-like members being coaxial and spaced apart from each other in the axial direction (A-A), thereby defining the ventilation portion (5), the axial direction (A-A) being coincident with or parallel to the rotational axis (X-X) of the disc (1), and the plate-like members (3, 4) comprising two outer surfaces (6, 7) defining opposite braking surfaces, the ventilation portion (5) comprises an outer radial edge (8), an inner radial edge (9), and a plurality of protrusions (10) projecting from the inner radial edge (9) in the radial direction (R-R) towards the rotational axis (X-X), wherein the protrusions (10) define a plurality of compartments (11), each compartment being positioned between one protrusion and another protrusion, the disc (1) is characterized in that: the ventilation portion (5) comprises a plurality of ventilation channels (17) circumferentially distributed in at least two rows, the ventilation channels (17) being adapted to ensure the flow of a cooling fluid between the two plate-like members (3, 4), the ventilation channels (17) lead to the outer radial edge (8) of the ventilation portion (5) through corresponding first openings (18) and lead to the compartments (11) through corresponding second openings (19), the first openings (18) being circumferentially distributed in at least two rows (37, 47) forming respective circumferential portions, the ventilation channels (17) are grouped into respective clusters (20), and the ventilation channels (17a, 17b, 17c, 17d) of each cluster (20) lead to the same compartment (11) through the second openings (19).
2. The disc (1) according to claim 1, wherein, each cluster in the clusters each comprises from 3 to 14 ventilation channels (17), preferably each cluster in the clusters each comprises from 4 to 10 ventilation channels (17), so as to lead to the outer radial edge (8) of the ventilation portion (5) through the first openings (18), preferably, the surface extension of the first opening (18) corresponding to the outermost ventilation channels (17a, 17b) of each cluster (20) is larger than the surface extension of the first opening (18) corresponding to the innermost ventilation channels (17c, 17d) of each cluster (20), and preferably, the circumferential extension of the first opening (18) corresponding to the outermost ventilation channels (17a, 17b) of each cluster (20) is larger than the circumferential extension of the first opening (18) corresponding to the innermost ventilation channels (17c, 17d) of each cluster (20).
3. The disk (1) according to any one of the preceding claims, wherein, each of the clusters (20) has a circumferential width included in the range of about 25° to about 60°, preferably, each of the clusters (20) has a circumferential width included in the range of about 30° to about 45°, and more preferably, each of the clusters (20) has a circumferential width of about 36°.
4. The disk (1) according to any one of the preceding claims, wherein, the number of the clusters (20) included in the ventilation portion (5) is included between 6 and 14, preferably, the number of the clusters (20) included in the ventilation portion (5) is included between 8 and 12, and more preferably, the number of the clusters (20) included in the ventilation portion (5) is equal to 10.
5. The disk (1) according to any one of the preceding claims, wherein, the first openings (18) are equidistant from each other.
6. The disk (1) according to any one of the preceding claims, wherein, each of the clusters (20) includes 4 ventilation channels (17), the ventilation channels (17) include a first peripheral ventilation channel (17a), a second peripheral ventilation channel (17b), and two internal ventilation channels (17c, 17d) arranged between the peripheral ventilation channels (17a, 17b), the peripheral ventilation channels (17a, 17b) lead to the outer radial edge (8) of the ventilation portion (5) through the following first openings (18): the surface extension of the first openings (18) of the peripheral ventilation channels (17a, 17b) is larger than the surface extension of the first openings (18) of the internal ventilation channels (17c, 17d), and preferably, the extension of the first openings (18) of the peripheral ventilation channels (17a, 17b) in the circumferential direction is larger than the extension of the first openings (18) of the internal ventilation channels (17c, 17d) in the circumferential direction.
7. The disk (1) according to any one of the preceding claims, wherein, the cross-section of each ventilation channel (17) in a plane perpendicular to the rotation axis (X-X) is defined by the following: an arc-shaped portion (21) of the circumferential portion at the outer radial edge (8) of the ventilation portion (5); two straight lines (22, 23) converging away from the outer radial edge (8), the straight lines (22, 23) being defined by two first ends (21', 21") and two second ends (24, 25), the first ends corresponding to the ends of the arc-shaped portion (21) of the circumferential portion, and two parallel or substantially parallel straight lines (26, 27), the straight lines (26, 27) extending from the second ends (24, 25) until one of the compartments (11).
8. The disk (1) according to any one of the preceding claims, wherein, The first opening (18) has a grooved, oval or substantially oval shape, and / or the second opening (19) has a circular, substantially circular, oval or substantially oval shape.
9. The disc (1) according to any one of the preceding claims, the disc (1) comprising a plurality of axial ventilation channels (28) which lead to the braking surfaces of the plate-like members (3, 4) through respective openings, the axial ventilation channels (28) being adapted to provide a flow of cooling fluid: the flow of cooling fluid provided by the axial ventilation channels (28) is substantially orthogonal to the flow of cooling fluid flowing in the ventilation channels (17) which are circumferentially distributed in at least two rows (37, 47) in the ventilation section (5).
10. The disc (1) according to any one of the preceding claims, wherein, each layer (100, 101, 102, 103) of carbon fiber comprises a plurality of radial segments (104) and transverse segments (105), the radial segments and the transverse segments being placed side by side and joined together to form the layer, wherein the radial segments (104) are segments in which the carbon fiber is mainly oriented in the radial direction (R) relative to the overlapping axis, and the transverse segments (105) are segments in which the carbon fiber is mainly oriented in an intersecting direction (I) intersecting the radial direction, preferably, the intersecting direction (I) is substantially orthogonal to the radial direction (R), wherein each radial segment (104) is adjacent to and joined to transverse segments (105) on both sides, and each transverse segment (105) is adjacent to and joined to radial segments (104) on both sides, thereby forming alternating radial segments (104) and transverse segments (105) in each layer (100, 101, 102, 103).
11. The disc according to claim 10, wherein, relative to the overlapping axis, the segments (104, 105) of the layer are angularly offset relative to the segments (104, 105) of adjacent layers such that the joint zones (106) between the segments do not overlap in the thickness of the disc (1).
12. The disc according to claim 10 or 11, wherein, the segments (104, 105) are formed in a substantially continuous manner as a spiral around the overlapping axis on a plurality of the layers (100, 101, 102, 103) of carbon fiber, preferably, the inclination of each layer (or turn) relative to the axis orthogonal to the overlapping axis is included in the range of 1° to 10°, more preferably, the inclination of each layer (or turn) relative to the axis orthogonal to the overlapping axis is included in the range of 1° to 5°, and the inclination of each layer (or turn) relative to the axis orthogonal to the overlapping axis is about 1°.
13. The disc according to any one of claims 10 to 12, wherein, The section (104, 105) is in the form of a coronal annular arc having a circumferential width included in the range of 60° to 90°, for example, the coronal annular arc having a circumferential width of about 68°.
14. The disk according to any one of claims 10 to 13, wherein, each section (104, 105) mainly comprises or only comprises unidirectional carbon fibers arranged along the radial direction (R) or the intersecting direction (I), preferably, at least a part of the carbon fibers is derived from oxidized polyacrylonitrile fibers, and preferably all carbon fibers are derived from oxidized polyacrylonitrile fibers.
15. The disk according to any one of claims 10 to 14, the disk comprising silicon carbide (SiC) obtained by reaction of at least a part of the silicon (Si) penetrating into the disk with a part of the carbon (C) in the carbon fibers and / or the carbonaceous matrix of the disk, preferably, the silicon carbide (SiC) is arranged to bridge adjacent layers of carbon fibers.
16. The disk according to any one of claims 10 to 15, wherein, the disk has a residual porosity of less than 5%, for example, the disk has a residual porosity equal to or less than 3%.