brake disc assembly

Abstract

The present invention is entitled "Brake Disc Assembly." In some examples, the present invention discloses a brake disc assembly comprising a single continuous core portion defining a core of the brake disc assembly; and a friction portion adjacent to the core portion. The friction portion defines the friction surface of the brake disc assembly during braking operation. The friction portion comprises a carbon composite material. The core portion comprises a core material that is not a carbon composite material and is configured as a heat sink for the brake disc assembly for heat generated during braking operation.

Description

Technical Field

[0001] The present disclosure relates to braking systems, such as aircraft braking systems. Background Art

[0002] Aircraft braking systems can be used for various purposes, such as slowing or stopping an aircraft while maneuvering on the ground. For example, when a jet-powered aircraft is landing, the aircraft braking system, various aerodynamic drag sources (e.g., fins, spoilers, etc.), and aircraft thrust reversers can be used to slow the aircraft down within a desired runway distance. Once the aircraft has sufficiently slowed down and is taxiing from the runway toward its ground destination, the aircraft braking system can be used to slow the aircraft down and bring it to a stop at its final ground destination. Summary of the Invention

[0003] In some examples, the present disclosure describes a brake disc assembly that includes a single continuous core portion and one or more friction portions. When used in a braking operation, the core portion may define a core of the brake disc assembly, and the friction portion may define a friction surface of the brake disc assembly. The friction portion may be formed from a carbon composite material, while the core portion may be formed from a core material other than a carbon composite material. For example, the core material may be a material having a relatively high volumetric specific heat capacity, such as compared to a carbon composite material used for the friction portion of the assembly. The core portion may be configured to serve as a heat sink for the brake disc assembly to dissipate heat generated during braking operation.

[0004] In one example, a brake disc assembly includes a single continuous core portion defining a core of the brake disc assembly; and a friction portion adjacent to the core portion, the friction portion defining a friction surface of the brake disc assembly during braking operation, wherein the friction portion includes a carbon-carbon composite material, wherein the core portion includes a core material that is not a carbon-carbon composite material, and wherein the core portion is configured as a heat sink for the brake disc assembly for heat generated during braking operation.

[0005] In another example, a method for forming a brake disc assembly is provided, the method comprising: positioning a single continuous core portion adjacent to a friction portion; and attaching the core portion to the friction portion, wherein the core portion defines a core of the brake disc assembly, wherein the friction portion defines a friction surface of the brake disc assembly during a braking operation, wherein the friction portion comprises a carbon-carbon composite, wherein the core portion comprises a core material that is not a carbon-carbon composite, and wherein the core portion is configured as a heat sink for the brake disc assembly for heat generated during braking operation.

[0006] The details of one or more examples of the present disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the present disclosure will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a conceptual diagram illustrating an exemplary wheel and brake assembly that may include a brake disc assembly formed according to the techniques of this disclosure.

[0008] Figure 2A and Figure 2B is a conceptual diagram illustrating an exemplary brake disc assembly according to an example of the present disclosure.

[0009] Figure 3A-3C is a conceptual diagram illustrating another exemplary brake disc assembly according to an example of the present disclosure.

[0010] Figure 4A is a schematic front view of an example brake disc assembly according to an example of the present disclosure.

[0011] Figure 4B is a schematic cross-sectional side view of an example brake disc assembly according to an example of the present disclosure.

[0012] Figure 4C is a schematic cross-sectional side view of an exemplary core portion according to examples of the present disclosure.

[0013] Figure 4D is a schematic cross-sectional side view of an exemplary friction pad according to an example of the present disclosure.

[0014] Figure 5 is a flow chart illustrating an exemplary technique for assembling a brake rotor assembly according to examples of the present disclosure.

[0015] Figure 6 is a table listing various properties of exemplary materials.

[0016] Figure 7 is a graph of specific heat*density versus temperature for various exemplary materials.

[0017] Figure 8 is a schematic diagram illustrating another exemplary brake disc assembly.

[0018] Figures 9A-9C is a photograph of an exemplary brake disc assembly. DETAILED DESCRIPTION

[0019] In some examples, the present disclosure describes a brake disc assembly that includes a single continuous core portion and one or more friction portions, such as friction pads. The friction portion may be formed from a carbon-carbon composite material, while the core portion may be formed from a material other than a carbon-carbon composite material, such as another type of ceramic material or a metallic material. The carbon-carbon composite friction portion may be carbon fibers in a carbon matrix.

[0020] In an exemplary aircraft braking system, one or more rotatable brake discs ("rotors") may be mechanically connected to one or more wheels of the vehicle, and one or more stationary brake discs ("stators") may be mechanically connected to the body of the aircraft. The rotatable and stationary brake discs may be alternately splined to the torque tube or wheel rim of the aircraft wheel to define a brake disc stack. To generate the desired braking force, a brake actuator may engage the rotatable and stationary brake discs with each other. Friction between the brake discs converts the kinetic energy of the moving aircraft into heat energy, thereby slowing or stopping the aircraft.

[0021] In some examples, such braking systems may use brake discs formed entirely of steel. In other examples, carbon-carbon composite brake discs (e.g., where the brake disc is made entirely of a carbon composite material) may be used in place of steel brake discs, for example, in an attempt to reduce the weight of the brake disc compared to a steel brake disc. However, replacing steel brake discs with carbon-carbon composite brake discs may present one or more issues, for example, in a braking system designed for use with steel brake discs. For example, the volume available within the brake assembly for friction material allocated to the disc may be fixed, which may reduce the useful life of the carbon composite disc before the disc needs to be replaced. Additionally, using an entirely carbon-carbon composite material within the allocated volume may present issues with the ability of the brake pad to serve as a heat sink, for example, during braking operation, while also serving as friction material for a desired useful life.

[0022] According to some examples of the present disclosure, a brake disc may include a single continuous core portion and a friction portion adjacent to the core portion. For example, the friction portion, in the form of one or more friction pads, may define a friction surface of the brake disc during operation in a braking system. The core portion may be adjacent to the friction portion to define a heat sink for the brake disc assembly during braking operation. The friction portion may be formed from a carbon-carbon composite material, while the core portion may be formed from a material other than a carbon-carbon composite material.

[0023] In this way, a carbon-carbon composite material can define the friction surface of the brake disc, while a single continuous core portion can be defined by a material, such as steel or other materials described herein, having a higher volumetric heat capacity (which is equal to the specific heat multiplied by the density (specific heat * density)) than the carbon-carbon composite material. For example, such a combination can allow the brake disc assembly to have a greater heat capacity within a smaller volume than a brake disc formed entirely from a carbon-carbon composite material. As a result, more of the total allocated volume of the brake assembly can be allocated to the wear-resistant material, which increases the wear life of the brake disc while still providing the desired heat capacity within the total volume of the brake disc. In other words, for a given total disc volume, the volume of friction material can be relatively high because, due to the higher specific heat * density of the core portion, the core portion can have a smaller volume while providing an adequate heat sink for the brake disc.

[0024] For ease of description, "specific heat*density" will be used interchangeably with volumetric heat capacity in this disclosure.

[0025] In some examples, such hybrid brake discs comprising a carbon-carbon composite friction portion and a single continuous core portion defined by a non-carbon-carbon composite material may provide one or more benefits. For example, in the context of replacing steel brake discs in an existing brake system, wear life may be increased compared to all steel brake discs or all carbon-carbon composite brake discs within the volume allocated for brake discs within the brake system. In some examples, the use of hybrid brake discs may increase the brake disc's Landings Per Overhaul (LPO) by up to two times compared to carbon-carbon composite brake discs, while still reducing weight compared to steel brake discs.

[0026] Figure 1 is a conceptual diagram illustrating an exemplary wheel and brake assembly 10 according to an example of the present disclosure, which may include one or more "hybrid" brake discs. For ease of description, examples of the present disclosure will be primarily described with respect to aircraft brake assemblies. However, the articles of the present disclosure may be used to form brake components other than aircraft brake discs. For example, the brake components may be used as friction materials in other types of braking applications and vehicles.

[0027] exist Figure 1 In the example shown, wheel and brake assembly 10 includes wheel 12, actuator assembly 14, brake stack 16, and axle 18. Wheel 12 includes hub 20, wheel leg flange 22, bead seats 24A and 24B, lug bolts 26, and lug nuts 28. Actuator assembly 14 includes actuator housing 30, actuator housing bolts 32, and plunger 34. Brake stack 16 includes alternating rotor brake discs 36 and stator brake discs 38; rotor brake discs 36 are configured to move relative to stator brake discs 38. Rotor brake discs 36 are keyed to wheel 12, and in particular to hub 20, via beam keys 40. Stator brake discs 38 are mounted to axle 18, and in particular to torque tube 42, via rack 44. Wheel and brake assembly 10 can support any type of private, commercial, or military aircraft or other type of vehicle.

[0028] The wheel and brake assembly 10 includes a wheel 12 having a Figure 1 In the example shown, wheel 12 is defined by a hub 20 and wheel leg flanges 22. Wheel leg flanges 22 can be mechanically secured to hub 20 by lug bolts 26 and lug nuts 28. Wheel 12 defines bead seats 24A and 24B. During assembly, an inflatable tire (not shown) can be placed over hub 20 and secured on the opposite side by wheel leg flanges 22. Thereafter, lug nuts 28 can be tightened onto lug bolts 26, and the inflatable tire can be inflated with bead seats 24A and 24B, thereby providing an airtight seal for the inflatable tire.

[0029] The wheel and brake assembly 10 may be mounted to a vehicle via the torque tube 42 and the axle 18. Figure 1 In the example shown, a torque tube 42 is attached to the shaft 18 by a plurality of bolts 46. The torque tube 42 supports the actuator assembly 14 and the stator brake disc 38. The shaft 18 may be mounted on a strut of a landing gear (not shown) or other suitable component of a vehicle to connect the wheel and brake assembly 10 to the vehicle.

[0030] During vehicle operation, braking may be required from time to time, such as during landing and taxiing of an aircraft. The wheel and brake assembly 10 is configured to provide braking functionality to the vehicle via an actuator assembly 14 and a brake stack 16. The actuator assembly 14 includes an actuator housing 30 and a plunger 34. The actuator assembly 14 may include different types of actuators, such as one or more of an electro-mechanical actuator, a hydraulic actuator, a pneumatic actuator, etc. During operation, the plunger 34 may extend away from the actuator housing 30 to axially compress the brake stack 16 against a compression point 48 for braking.

[0031] The brake stack 16 includes alternating rotor brake discs 36 and stator brake discs 38. The rotor brake discs 36 are keyed to the hub 20 for common rotation via beam keys 40. The stator brake discs 38 are keyed to the torque tube 42 via key teeth 44. Figure 1 In the example shown, the brake stack 16 includes four rotors and five stators. However, in other examples, a different number of rotors and / or stators may be included in the brake stack 16.

[0032] In some examples, the rotor brake disc 36 and the stator brake disc 38 can be mounted in the wheel and brake assembly 10 via a beam key 40 and a rack 44, respectively. In some examples, the beam key 40 can be spaced circumferentially around the inner portion of the hub 20. For example, the beam key 40 can be shaped to have opposing ends (e.g., opposing sides of a rectangle) and can have one end mechanically secured to the inner portion of the hub 20 and an opposing end mechanically secured to the outer portion of the hub 20. The beam key 40 can be integrally formed with the hub 20 or can be separate from the hub 20 and mechanically secured to the hub 20, for example, to provide a thermal barrier between the rotor brake disc 36 and the hub 20. To this end, in various examples, the wheel and brake assembly 10 can include a heat shield (not shown) that extends radially outward and outwardly around the brake stack 16, for example, to limit heat transfer between the brake stack 16 and the wheel 12.

[0033] In some examples, the key teeth 44 can be spaced circumferentially around the outer portion of the torque tube 42. As such, the stator brake disc 38 can include a plurality of radially inwardly disposed lug slots along the inner diameter of the disc that are configured to engage the rack 44. Similarly, the rotor brake disc 36 can include a plurality of radially inwardly disposed lug slots along the outer diameter of the disc that are configured to engage the beam keys 40. As such, the rotor brake disc 36 will rotate with the movement of the wheel while the stator brake disc 38 remains stationary, allowing the friction surfaces of adjacent stator brake discs 38 and rotor brake discs 36 to engage each other, thereby slowing the rotation of the wheel 12.

[0034] The rotor brake discs 36 and stator brake discs 38 provide opposing friction surfaces for braking the aircraft. As the kinetic energy of the moving aircraft is converted into heat energy in the brake stack 16, the temperature in the brake stack 16 may rise rapidly. Accordingly, the rotor brake discs 36 and stator brake discs 38 forming the brake stack 16 may be made of a strong, thermally stable material that can operate at very high temperatures and dissipate heat quickly. As torque is applied to the brake stack 16, the stresses in the brake stack 16 may increase. Accordingly, the rotor brake discs 36 and stator brake discs 38 forming the brake stack 16 may be made of a high-strength, corrosion-resistant material that can operate under very high stresses. However, these thermal and structural properties may not be achievable in a single material. For example, a material with high thermal stability may not effectively transfer heat or provide high strength.

[0035] In some examples, at least one of the rotor brake discs 36 and / or at least one of the stator brake discs 38 is formed from a single continuous core portion and one or more friction pads on one or more sides of the core portion. The one or more friction pads may define a friction portion of each of the brake discs 36, 38. As described herein, the one or more friction pads may be formed from a carbon-carbon composite material, while the single continuous core portion may be defined by a material other than a carbon-carbon composite material, for example, where the material has a higher specific heat density than the carbon-carbon composite material defining the one or more friction pads.

[0036] Figure 2A is a conceptual diagram of an exemplary brake disc assembly 50 according to an example of the present disclosure. Figure 2B It is shown along Figure 2A A conceptual diagram of a view of a brake disc assembly 50 is shown in cross section AA. The brake disc assembly 50 includes a core portion 52 and a plurality of friction pads on one or more sides of the core portion 52. Figure 2A and Figure 2B In the example of FIG. 5 , the plurality of friction pads includes a first friction pad 54A and a second friction pad 54B (individually referred to as “friction pad 54 ” and collectively referred to as “the plurality of friction pads 54 ”).

[0037] The brake disc assembly 50 can be used to Figure 1 Any one or more of the rotor brake disc 36 and / or the stator brake disc 38. As used herein, "brake disc" and "brake disc assembly" are used interchangeably to describe either the rotor disc or the stator disc. Likewise, the terms "friction pad" and "core section" are used to describe the friction pad of either the rotor disc or the stator disc and a single continuous core section that defines, for example, a heat sink for the brake disc during operation, and are not intended to confer a geometric configuration specific to one or the other.

[0038] The core portion 52 may be a disk or annulus having a first core surface 58A and a second core surface 58B (individually referred to as "core surface 58" and collectively referred to as "core surfaces 58") that are oriented opposite each other and configured to receive and connect with corresponding friction pads 54A and 54B. Accordingly, each friction pad 54 may be a disk or annulus having a corresponding pad surface oriented opposite each other at an interface with the core surface 58 and corresponding friction surfaces 60A and 60B (individually referred to as "friction surface 60" and collectively referred to as "friction surfaces 60"). Each pad surface 60 of the friction pad 54 is configured to be received by the core portion 52 and connect with the core surface 58 on the same side of the core portion 52 and a support structure, such as another friction pad 54, on the opposite side of the core portion 52. The exposed friction surfaces 60 of the friction pads 54 frictionally engage the opposing brake disk during braking operation.

[0039] In another example, the plurality of friction pads are formed from a plurality of radial segments that together form a disk or annulus, rather than from a single component. For example, in the case of an annular ring, the friction pad 54 may be formed from four segments, each segment being approximately 90 degrees of the full 360 degree ring.

[0040] By forming the core portion 52 and the friction pad 54 as separate components, the materials forming the core portion 52 and the friction pad 54 can be tailored to exhibit different mechanical, chemical, and / or thermal properties, such as improved friction properties of the friction pad 54 and improved strength, corrosion resistance, and / or thermal properties of the core portion 52. For example, the core portion 52 can be formed from a material having desired thermal properties to serve as a heat sink in a relatively small volume, while the friction pad 54 can be formed from a carbon-carbon composite material having desired friction properties.

[0041] In some examples, the core portion 52 and the friction pad 54 can include various structures and surface features configured to relieve stress and / or remove heat from the friction pad 54 to allow for further differentiation of material properties between the core portion 52 and the friction pad 54. The resulting brake disc assembly 50 can exhibit both improved strength within the underlying core portion 52 and improved friction properties associated with the friction pad 54.

[0042] According to some examples of the present disclosure, the friction pads 54 may be formed of a carbon-carbon composite material, while the core portion 52 may be formed of a different material, such as a metal or ceramic material other than the carbon-carbon composite material. The carbon-carbon composite material of the friction pads 54 may exhibit desirable friction characteristics, while the core portion 52 may be formed of a material having more desirable properties as a heat dissipation material (e.g., by having a specific heat density greater than that of the friction pads 54). Additionally, the core portion 52 may be formed of a single continuous piece of material, for example, rather than being formed by a combination of two or more pieces of the same or different materials between the friction pads 54. This may allow the core portion 52 to better serve as a heat sink for the brake disc 50, for example, due to better heat transfer characteristics within the core portion 52.

[0043] The carbon-carbon composite material forming the friction pad 54 may include carbon fibers within a carbon matrix (e.g., graphite). In some examples, the friction pad 54 may be formed from a carbon-carbon composite material made from a dense carbon material. In some examples, the carbon material may include a variety of carbon fibers and dense materials. The carbon fibers may be composed of carbon or a carbon precursor material such as polyacrylonitrile (PAN) or rayon, which may be converted to carbon through a carbonization process. The carbon fibers used to form the friction pad 54 may be arranged in a woven or non-woven fabric as either a single layer or a multilayer structure. In some examples of both the friction pad 54A and the friction pad 54B, depending on the desired mechanical or friction properties, both the friction pad 54A and the friction pad 54B may include the same underlying carbon structure (e.g., both are woven), or each may include different carbon fiber structures (e.g., woven and non-woven friction pads). In some examples, the carbon-carbon composite material may include woven carbon fibers and a matrix material (e.g., carbonized pitch or resin). In some examples, the carbon matrix may be pyrolytic graphite. In some examples, the carbon fibers may be pyrolyzed carbon fibers.Other matrices and fibers for the carbon-carbon composite material of the friction pad 54 are contemplated.

[0044] The carbon-carbon composite material of the friction pad 54 can be manufactured using any suitable technique. For example, the friction pad 54 can be formed by densifying a carbon fiber preform comprising a fabric sheet layer formed from woven or non-woven carbon fibers. Densification of the carbon fiber preform can include infiltrating the preform with liquid pitch using vacuum pressure infiltration (VPI) and / or resin transfer molding (RTM), and then carbonizing the pitch to obtain a carbon-carbon composite material exhibiting a desired final density. Additionally or alternatively, chemical vapor infiltration (CVI) or chemical vapor deposition (CVD) can be used to densify the fabric preform. In some examples, the densified carbon-carbon composite material of the pad 54 exhibits a density greater than or equal to about 1.7 grams per cubic centimeter (g / cc), such as between about 1.75 g / cc and about 1.90 g / cc.

[0045] In some examples of CVD / CVI, the carbonized preform is in a retort under the cover of an inert gas, such as heating under a pressure lower than 100 Torr. When the carbonized preform reaches a temperature between approximately 900 degrees Celsius and approximately 1200 degrees Celsius, the inert gas is replaced by a combination of at least two of carbon-containing gases such as natural gas, methane, ethane, propane, butane, propylene or acetylene or these gases. When the carbon-containing gas flows around the carbonized preform and passes through the carbonized preform, a group of complicated dehydrogenation, condensation and polymerization reactions take place, thereby carbon atoms are deposited on the inside and on the surface of the carbonized preform. Over time, when more and more carbon atoms are deposited on the surface of the hole in the carbonized preform, the carbonized preform becomes more dense. This process can be referred to as densification, because the open space in the carbonized preform is finally filled with carbon matrix, until forming a roughly solid carbon component. US Patent Application Publication No. 2006 / 0046059 (Arico et al.), the entire disclosure of which is incorporated herein by reference, provides an overview of exemplary CVD / CVI processes that may be used with the techniques described herein.

[0046] The core portion 52 can serve as a heat sink for the brake disc assembly 50 during braking operations. For example, heat generated by the frictional interaction between adjacent friction pads 54 during braking can be conducted from the friction pads 54 into the core portion 52. As described above, the core portion 52 is formed as a single continuous component, rather than being formed from multiple discrete components. Therefore, heat can be more easily conducted throughout the core portion 52.

[0047] To allow the core portion 52 to act as a heat sink, the first core surface and the second core surface 58 of the core portion 52 may include a high percentage (e.g., greater than 50%, such as approximately 95% or greater) of surface area that is configured to thermally contact the friction pad 54. The adjacent surface of the friction pad 54 may be in thermal contact with the core surface 58 by being close enough so that the friction pad 54 transfers heat to the first core surface and the second core surface 58, such as by direct contact or by contact through an intermediate layer. Accordingly, the adjacent surface of the friction pad 54 may include a high percentage of surface area that is configured to thermally contact the core portion 52 along the surface 58. The high percentage of surface area of ​​the core portion 52 and the friction pad 54 that is in thermal contact may provide improved heat removal and dissipation (e.g., a higher heat removal rate, lower temperature, and / or more uniform temperature distribution) from the friction pad 54 to the core portion 52. This helps to improve friction performance because the friction pad is less likely to become thermally saturated, which results in reduced friction until heat is able to dissipate from the friction surface. Although Figure 2B The cross-section of FIG shows the core portion 52 as extending from the inner diameter (ID) to the outer diameter (OD) of the annular disk, but in other examples, the pad 54 may completely enclose the core portion 52 or at least extend above the core portion 52 at either the ID or OD of the annular disk, for example to increase the surface area of ​​the pad 54 in contact with the core portion 52.

[0048] As described herein, the core portion 52 may be formed of a material different from the carbon-carbon composite material of the friction pad 54. For example, the core portion 52 may not be formed of a carbon-carbon composite material. In some examples, the core portion 52 is formed of a metal or ceramic material. Exemplary materials for the core portion 52 may include titanium (including titanium alloys such as titanium nickel and / or titanium aluminum alloys), steel, or a ceramic matrix composite containing materials such as tungsten carbide, boron nitride, boron carbide, silicon carbide, or silicon nitride. In some examples, the core portion 52 includes, consists of, or consists essentially of at least one of steel, tungsten carbide, boron nitride, boron carbide, or silicon carbide. In some examples, the core portion 52 includes, consists of, or consists essentially of titanium, titanium nickel alloy, or titanium aluminum alloy. Examples of steel materials may include steel 17-22A(S) and / or steel 17-22A(V). In some examples, the core portion includes, consists of, or consists essentially of a nickel-based superalloy (such as superalloy MAR-M-247). Exemplary titanium alloys may include Ti-6Al-6V-2Sn and / or Ti-0.8Ni-0.3Mo.

[0049] The material of the core portion 52 can have a specific heat density greater than the carbon-carbon composite material of the friction pad 54. In some examples, the core portion 52 has a specific heat density of at least about 1.5 J / cm^3K or greater at room temperature, such as about 2.3 J / cm^3K to about 2.8 J / cm^3K or about 2.9 J / cm^3K to about 3.8 J / cm^3K. As such, the core portion 52 can serve as a better heat sink for the brake assembly than a brake pad assembly having the same volume as the brake pad assembly 50 but formed entirely of the carbon-carbon composite material of the friction pad 54. Similarly, the brake pad assembly 50 can be lighter in weight than a similarly sized brake pad assembly formed entirely of, for example, steel.

[0050] The material of the core portion 52 may have a relatively high heat dissipation rate, for example, greater than the heat dissipation rate of the carbon-carbon composite material of the friction pad 54. In some examples, the core portion 52 has a heat dissipation rate of at least about 0.54 J / s^(1 / 2)-cm^2–K or greater at room temperature, such as about 0.74 J / s^(1 / 2)-cm^2–K to about 1.32 J / s^(1 / 2)-cm^2–K or about 1.40 J / s^(1 / 2)-cm^2–K to about 1.7 J / s^(1 / 2)-cm^2–K. In comparison, a carbon-carbon composite material has a heat dissipation rate of about 0.54 J / s^(1 / 2)-cm^2–K at room temperature. As such, the core portion 52 may serve as a better heat sink for the brake assembly because the core portion 52 readily absorbs heat, for example, from the friction pad 54, rather than forming a "bottleneck" for heat transfer at the interface between the friction pad 54 and the core portion 52. In some examples, the steel material used for the core portion 52 may have a thermal dissipation rate of approximately 1.32 J / s^(1 / 2)-cm^2–K at room temperature. In some examples, the titanium alloy material used for the core portion 52 (such as Ti-0.8Ni-0.3Mc) may have a thermal dissipation rate of approximately 0.74 J / s^(1 / 2)-cm^2–K at room temperature. In some examples, the tungsten carbide material used for the core portion 52 may have a thermal dissipation rate of approximately 1.47 J / s^(1 / 2)-cm^2–K at room temperature. In some examples, the boron nitride material used for the core portion 52 may have a thermal dissipation rate of approximately 1.41 J / s^(1 / 2)-cm^2–K at room temperature. In some examples, the silicon carbide material used for the core portion 52 may have a thermal dissipation rate of approximately 1.67 J / s^(1 / 2)-cm^2–K at room temperature.

[0051] Figure 6 is a table of various properties of carbon-carbon composite materials (labeled "Carbon") that can be used to form the friction pad 54, as well as other exemplary materials that can be used for the core portion. Figure 6As shown, the specific heat*density (Cp*ρ) of steel alloy (A709Gr50), titanium alloy (Ti-6Al-6V-2Sn and Ti-0.8Ni-0.3Mo) and tungsten carbide is greater than that of carbon-carbon composites.

[0052] Figure 7 A graph showing the specific heat density versus temperature (degrees Celsius) for pyrolytic graphite, boron nitride, silicon carbide, carbon steel, and titanium. In the graph, the area under each curve represents the energy capacity per unit volume of each material. Therefore, a material with a larger area under its corresponding curve can hold more energy in a smaller volume.

[0053] The friction pads 54 can be coupled (e.g., permanently or removably coupled) to the core portion 52 using any suitable technique. For example, the friction pads 54 can be riveted or mechanically fastened to the structural core portion 52 in some manner. The rivets may not be intended to bear loads, but rather to hold the pieces together only when no pressure is applied to the disc. Another form of fastening can be brazing the carbon-carbon composite material of the pad to steel or other core portion material to form a bond at a localized location. In examples where the friction pads 54 are removably coupled to the core portion 52, for example, once the friction pads 54 are worn to a certain extent due to braking operation, the friction pads 54 can be replaced and the core portion 52 can be reused.

[0054] In some examples, as described further below, the first and second core surfaces 58 of the core segment 52 may include one or more structural features configured to mate with and connect with one or more friction pads 54. Accordingly, the pad surfaces of the friction pads 54 adjacent the core surfaces 58 may include one or more structural features configured to mate with and connect with the one or more structural features of the core segment 52. The structural features of the core segment 52 and the friction pads 54 may provide improved load distribution, better friction pad retention, reduced costs associated with manufacturing and assembly, and other benefits described in further detail below.

[0055] like Figure 2B In the example shown, the brake disc assembly 50 has a total thickness T(t), the first friction pad 54A has a thickness T(1), the core portion 52 has a thickness T(2), and the second friction pad 54B has a thickness T(3). In some examples, T(t) can be defined by the sum of T(1), T(2), and T(3). In some examples, the thickness of T(t) can be about 0.5 inches to about 2 inches. T(1) and T(3) can each be about 0.125 inches to about 1.00 inches. T(2) can be about 0.100 inches to about 0.50 inches. In some examples, T(1) can be substantially the same as or different from T(3). In some examples, T(1) can be substantially the same as or different from T(2).

[0056] By using a material for the core portion 52 that has a higher specific heat density than the carbon-carbon composite material of the friction pad 54, the volume of the core portion 52 can be reduced while still providing the desired heat sink function compared to a similar brake disc assembly formed from a carbon-carbon composite material rather than the exemplary hybrid design described herein. In some examples, the ratio of the volume of the core portion 52 made from a metal or ceramic material (or the exemplary materials for the core portion 52 described herein) to the volume of the core portion made from a carbon-carbon composite material can be at least about 0.9, such as about 0.88 to about 0.83 or about 0.55 to about 0.5.

[0057] Figure 3A-3C is a schematic diagram illustrating an example of a brake disc assembly 70. The brake disc assembly 70 may be substantially similar to the brake disc assembly 50, and like features are similarly numbered. Figure 3A An assembled view of the brake disc assembly 70 is shown including the core portion 52 , the first friction pad 54A, and the second friction pad 54B. Figure 3B An enlarged exploded view of a portion of brake disc assembly 70 is shown. Figure 3C The brake disc assembly 70 is shown without the friction pads 54 .

[0058] As shown, the core portion 52 is positioned between the friction pads 54A and 54B and is secured to the core portion 52 via a plurality of boss assemblies such as Figure 3B Boss assemblies 72 are coupled to friction pads 54. Each individual boss assembly 72 is positioned within a corresponding hole 74 in core portion 52 such that projections 64A and 64B protrude out of the plane of the surface of core portion 52. The projections of the boss assemblies mate with corresponding groove-like recesses in the opposing surface of brake pad 54. For example, Figure 3B As shown, boss projections 64B mate with groove-like recesses 62 formed in the opposing surface of friction pad 54B. Similarly, boss projections 64A mate with corresponding groove-like recesses (not shown) in the opposing inner surface of friction pad 54A.

[0059] Boss assembly 72 also includes boss core 66 and fastener 68. To assemble boss assembly 72 within hole 74 in core portion 52, boss protrusions 64A and 64B can mate with boss core 66 within hole 74 in core portion 52. Fastener 68 can be inserted through the holes in boss protrusion 64A, boss core 66, and boss protrusion 64B to fasten boss protrusion 64A, boss core 66, and boss protrusion 64B to one another within hole 74. When fastened, because boss protrusions 64A and 64B are larger than hole 74, outer portions of boss protrusions 64A and 64B overlap with opposing surfaces of core portion 52 to secure boss assembly 72 to core portion 52 within hole 74.

[0060] exist Figure 3A-Figure 3B In the example of FIG, boss assembly 72 can prevent pad 54 from rotating relative to core portion 52 during braking operation (e.g., when force is applied to the friction surface of pad 54). In some examples, such as when braking force is not applied, additional attachment features can be included in assembly 70 to attach pad 54 to core 52. For example, rivets or other mechanical fasteners can be used to attach pad 54 to core portion 52. Figure 8 is a schematic diagram illustrating an example of a brake rotor assembly 140 that is similar to assembly 70. The brake assembly includes a plurality of through-holes 142 extending through the pad 54 and the core portion 52. A rivet or other mechanical fastener may extend through each of the through-holes 142 to attach (e.g., clamp) the pad 54 to the core portion 52.

[0061] Figure 9A are photographs showing an exemplary friction pad (left) and stator core portion (right) having such through-holes. Figure 9B is a photograph showing an exemplary rotor core portion having similar through-holes. Figure 9C is a photograph of two brake disc assemblies comprising a stack of pads and core sections attached to one another with rivets passing through through holes in each of the friction pads and core sections. The stack may be used, for example, as Figure 1 The wheel and brake stack 16 of the brake assembly 10 .

[0062] Figure 4A is a schematic front view of another exemplary brake disc assembly 100 according to an example of the present disclosure, and Figure 4B According to the examples of the present disclosure Figure 4A Schematic cross-sectional side view of an exemplary brake disc assembly 100. The brake disc assembly 100 includes a core portion 102 and a plurality of friction pads on one or more sides of a single continuous core portion 102. Figure 4A and Figure 4B In the example of FIG. 1 , the plurality of friction pads includes a first friction pad 104A and a second friction pad 104B (individually referred to as “friction pad 104 ” and collectively referred to as “plurality of friction pads 104 ”). Figure 4A The rectangular dashed lines in the figure may represent dimples 110 that transfer torque from the friction pad to the structural core. The friction pad may be one continuous friction pad or a plurality of friction pads, for example, which may be arranged in a manner Figure 4A Arrangement of shapes shown.

[0063] The brake disc assembly 100 may be a reference Figure 2A and Figure 2BThe example of the brake disc assembly 50 is shown. The friction pad 104 can be formed of substantially the same material as described for the friction pad 54. The core portion 102 can be formed of substantially the same material as described for the core portion 52. For example, the friction pad 54 can be formed of a carbon-carbon composite material, and the core portion 102 can be formed of a material other than a carbon-carbon composite material.

[0064] The brake disc assembly 100 may be used with any one or more of the rotor brake disc 36 and / or the stator brake disc 38. The brake disc assembly 100 may be used as, for example, Figure 1 The rotor brake disc 36 or the stator brake disc 38 of the core portion 102 can be a disc or annulus having a first core surface 124A and a second core surface 124B (individually referred to as "core surface 124" and collectively referred to as "core surfaces 124") that are oriented opposite each other and are configured to receive and connect with corresponding friction pads 104A and 104B. Accordingly, each friction pad 104 can be a disc or annulus having corresponding pad surfaces 115A and 115B (individually referred to as "pad surface 115" and collectively referred to as "pad surfaces 115") and corresponding friction surfaces 112A and 112B (individually referred to as "friction surface 112" and collectively referred to as "friction surfaces 112") that are oriented opposite each other. Each pad surface 115 of the friction pad 104 is configured to be received by the core portion 102 and connect with a core surface 124 on the same side of the core portion 102 and a support structure, such as another friction pad 104 , on an opposite side of the core portion 102 .

[0065] The first core surface and the second core surface 124 of the core portion 102 may include one or more structural features configured to mate with and connect to one or more friction pads 104. Accordingly, the first pad surface and the second pad surface 115 of the friction pad 104 may include one or more structural features configured to mate with and connect to one or more structural features of the core portion 102. The structural features of the core portion 102 and the friction pad 104 may provide improved load distribution, better friction pad retention, reduced costs associated with manufacturing and assembly, and other benefits described in further detail below. The structural features of the core portion 102 may include, for example, one or more of geometrically complementary dimples 110 (shown in phantom) and corresponding bosses 116 for mating and distributing torque load forces between the core portion 102 and the corresponding friction pad 104.

[0066] The first and second core surfaces 124 of the core portion 102 may also include a high percentage of surface area configured to thermally contact the pad surface 115 of the friction pad 104. The first and second core surfaces 124 may thermally contact the friction pad 104 by being sufficiently close to the friction pad 104 so that the friction pad 104 transfers heat to the first and second core surfaces 124, such as through direct contact or through an intermediate layer or volumetric contact. Accordingly, the first and second pad surfaces 115 of the friction pad 104 may include a high percentage of surface area configured to thermally contact the core portion 102. The high percentage of surface area of ​​the core portion 102 and the friction pad 104 in thermal contact may provide improved heat removal and dissipation (e.g., a higher heat removal rate, lower temperature, and / or more uniform temperature distribution) from the friction pad 104 to the core portion 102. The proportion of the surface area of ​​the friction pad 104 that is in thermal contact with the core portion 102 may be, for example, greater than 50% of the total surface area of ​​the pad surface 115 of the corresponding friction pad 104 that faces the core portion 102 , such as greater than 70% of the total surface area of ​​the pad surface 115 , or greater than 90% of the total surface area of ​​the pad surface 115 .

[0067] The friction pads 104 may include one or more securing features configured to secure opposing friction pads 104 to one another. The securing features of the friction pads 104 may provide improved installation and manufacturing ease. The securing features of the friction pads 104 may include, for example, one or more holes 106 for extending between the friction pads 104 and securing fasteners 108.

[0068] The core segment 102 includes a first core surface 124A on a first side and a second core surface 124B on a second side. The core segment 102 also includes a plurality of dimples 110 extending between the first core surface 124A and the second core surface 124B. The first friction pad 104A includes a first friction surface 112A, a first flat pad surface 114A, and a first plurality of bosses 116A extending from the first flat pad surface 114A. The second friction pad 104B includes a second friction surface 112B, a second flat pad surface 114B, and a second plurality of bosses 116B extending axially outward (e.g., along the intended rotational axis of the core segment 102) from the second flat pad surface 114B. Each of the first plurality of bosses 116A includes a first aperture 106A, and each of the second plurality of bosses 116B includes a second aperture 106B.

[0069] like Figure 4BAs shown, when the brake rotor assembly 100 is assembled, the first flat pad surface 114A contacts the first core surface 124A, and the second flat pad surface 114B contacts the second core surface 124B. The first plurality of bosses 116A and the second plurality of bosses 116B engage with the plurality of dimples 110 of the core portion 102 to position the corresponding first friction pad 104A and the second friction pad 104B relative to the core portion 102. An elongated fastener of the plurality of elongated fasteners 108 passes through the first hole 106A of a corresponding one of the first plurality of bosses 116A and the second hole 106B of a corresponding one of the second plurality of bosses 116B to secure the first friction pad 104A and the second friction pad 104B to the core portion 102.

[0070] During braking, torque applied to and heat generated by the friction pad 104 can be transferred to the core portion 102. For example, the first and second friction surfaces 112A, 112B (individually "friction surface 112" and collectively "friction surfaces 112") can receive torque from an adjacent friction surface and transfer at least a portion of that torque to the core portion 102 through the first and second plurality of bosses 116A, 116B (individually "bosses 116" and collectively "bosses 116") of the friction pad 104, to the plurality of dimples 110 of the core portion 102. The friction surface 112 can also generate heat during braking and dissipate at least a portion of that heat from the core surface 124 of the core portion 102 to the core portion 102, to the first and second flat pad surfaces 114A, 114B (individually "flat pad surface 114" and collectively "flat pad surfaces 114") of the friction pad 104. The fasteners 108 securing the friction pads 104A and 104B can receive and transfer the tensile force to the opposing friction pad 104 and, accordingly, to the opposing core surface of the core portion 102. In this manner, torque and heat generated during braking can be transferred from the friction pad 104 to the core portion 102, allowing the friction pads 104 to operate at lower stress and / or lower or more uniform temperatures than a disc brake assembly that does not include the structural and surface features of the disc brake assembly 100.

[0071] Figure 4C1 is a schematic cross-sectional side view of an exemplary core portion 102 according to an example of the present disclosure. The core portion 102 includes a first core surface 124A, a second core surface 124B, and a plurality of dimples 110 extending between the first core surface 124A and the second core surface 124B. The core portion 102 is configured to position a friction pad 104 relative to the core portion 102 using the plurality of dimples 110. Each dimple in the plurality of dimples 110 is configured to engage with a boss in a plurality of bosses 116 of at least one friction pad 104 to position the corresponding friction pad 104 relative to the core portion 102. During attachment of the friction pad 104 to the core portion 102, the plurality of dimples 110 can receive the plurality of bosses 116 of the at least one friction pad 104, allowing the friction pad 104 to be quickly and / or easily positioned relative to the core portion 102.

[0072] Core section 102 is configured to receive braking force or torque from at least one friction pad 104 via a plurality of dimples 110. Each dimple in plurality of dimples 110 is configured to receive a boss from a plurality of bosses 116 of at least one friction pad 104 and includes a dimple wall 138 that intersects a plane of each core surface 124. During braking, at least a portion of dimple wall 138 can receive a portion of the braking force from the boss of the corresponding friction pad 104. As such, braking force can be distributed across the plurality of dimples 110. In some examples, each dimple in plurality of dimples 110 can be configured to receive a first boss (e.g., first boss 116A) from a first friction pad (e.g., first friction pad 104A) and a second boss (e.g., second boss 116B) from a second friction pad (e.g., second friction pad 104B), such that surfaces of the first boss and surfaces of the second boss can contact each other.

[0073] In addition to supporting the friction pads 104, the core portion 102 is configured to receive thermal energy from the at least one friction pad 104 via at least one of the core surfaces 124. Each core surface 124 can be configured to contact the flat pad surface 114 of at least one friction pad 104. The contact between the flat pad surface 114 of the respective friction pad 104 and the respective core surface 124 can provide thermal conduction of heat generated by the friction pad 104 to the respective core surface 124. In some examples, each core surface 124 can be configured such that at least 50% of the pad surface of the respective friction pad or combination of friction pads can contact the respective core surface 124. For example, each core surface 124 can have a shape and / or size such that substantially all of the pad surface of the respective friction pad not positioned in the plurality of dimples 110 can contact the respective core surface 124. In this way, heat can be removed from the friction pads 104 more quickly and / or more evenly, such that the friction pads 104 can have a lower and / or more uniform temperature than friction pads that do not have a high surface area contacting a structural member.

[0074] In some examples, core segment 102 includes a rim 136 on an outer edge of core segment 102. Ridge 136 defines a first rim surface 126A extending axially beyond first core surface 124A and a second rim surface 126B extending axially beyond second core surface 124B. Although not shown, rim 136 may include a drive region for coupling to a beam key. For example, core segment 102 may be coupled to the beam key via the drive region, rather than coupling friction pad 104 to the beam key, thereby reducing the complexity of manufacturing friction pad 104. Additionally or alternatively, rim 136 may be configured to increase the drive region contacting the beam key, which may more effectively distribute loads to the beam key. In some examples, rim 136 may be configured such that a gap exists between the outer edge of the corresponding friction pad and the inner radial surface of rim 136. This gap may reduce vibrations generated as friction pads wear by reducing contact between the friction surfaces of the rotor and stator and the outer diameter / inner diameter interface.

[0075] The core portion 102 may be a disk or annulus having a first core surface 124A and a second core surface 124B defining an inner diameter (ID) and an outer diameter (OD), the first core surface and the second core surface being oriented relative to each other and configured to receive the friction pad 104. The core portion 102 may have various dimensions (e.g., outer diameter, inner diameter, thickness, etc.), which may depend on its use (e.g., braking load). The thickness of the core portion 102 may depend on the strength and thermal aspects of the design of the core portion 102, as well as the material properties of the core portion 102. In some examples, the core portion 102 may have a thickness between the first core surface 124A and the second core surface 124B that is between about 0.125 inches and about 2 inches.

[0076] In some examples, the dimensions of the core portion 102 may be selected to provide improved thermal contact with the friction pad 104. For example, as the contact area between the surface of the core portion 102 and the friction pad 104 increases, the amount of thermal energy that can be transferred from the friction pad 104 to the core portion 102 increases for a given temperature gradient between the core portion 102 and the friction pad 104. In some examples, the core portion 102 may have an inner diameter and an outer diameter such that substantially all (e.g., greater than 95%) of the planar pad surface 114 of the friction pad 104 may be in contact with one of the core surface 124A or the core surface 124B when the friction pad 104 is received on the corresponding core surface 124.

[0077] In some examples, the plurality of dimples 110 and, accordingly, the plurality of bosses 116 can be configured to improve the structural integrity of the core portion 102 and the friction pad 104. For example, the plurality of bosses 116 and the plurality of dimples 110 can be sized to have an area parallel to the friction surface 112 to overcome shear load stresses applied to the plurality of bosses. As another example, the plurality of bosses 116 and the plurality of dimples can be sized to prevent the shear load on the core portion 102 from exceeding an integrity threshold. Thus, the plurality of dimples 110 and the plurality of bosses 116 can be sized to strike a balance between the structural integrity of the core portion 102 and the structural integrity of the friction pad 104. As another example, the plurality of dimples 110 and the plurality of bosses 116 can have a thickness sufficient to overcome the bearing load stresses.

[0078] The plurality of dimples 110 can be configured with a size, orientation, and distribution based on a variety of factors, including, but not limited to, the surface area of ​​each dimple, the surface area of ​​the plurality of dimples, the ratio of tangential surface area (e.g., the surface area of ​​each dimple in a direction tangential to the direction of rotation of the core segment 102) to axial surface area, and the like. In some examples, the size, shape, and location of the plurality of dimples 110 can be standardized, allowing a variety of friction pads 104 with different characteristics to be used with the core segment 102. For example, the service life of the core segment 102 can be significantly longer than that of the friction pads 104, allowing the friction pads 104 to be replaced and, in some cases, upgraded with other friction pads 104. As another example, a universal friction pad 104 can be used with a variety of core segments 102. For example, the core segment of a rotor with a drive region on its outer diameter can differ slightly from the core segment of a stator with a drive region on its inner diameter, but both the rotor and the stator can use the same friction pad. Such cross-compatibility can reduce the number of friction pad 104 designs used to form a brake.

[0079] The plurality of dimples 110 can have a variety of sizes and dimensions. In some examples, each dimple in the plurality of dimples has a circumferential dimension (e.g., measured from the center of each dimple along an arc of rotation parallel to the direction of rotation of the core portion 102) between about 0.25 inches (such as for a large number of dimples 110 and / or friction pads 104) and about 12 inches (such as for a small number of dimples 110 and / or friction pads 104). In some examples, each dimple in the plurality of dimples has a radial dimension (e.g., measured from the center of each dimple along a radial direction from the center of the core portion 102) between about 0.25 inches and about 8 inches. The plurality of dimples 110 can have various numbers. In some examples, the number of dimples 110 ranges from 3 (such as for a design with a small number of friction pads 104, each having a high surface area) to 36 (such as for a design with a large number of friction pads 104, each having a low surface area).

[0080] The plurality of dimples 110 may have a variety of shapes in the radial plane, including but not limited to rectangular, rounded rectangular, circular, wedge-shaped, etc. In some examples, the plurality of dimples 110 may have a shape and orientation with a high tangential surface area. For example, Figure 4A As shown, a braking force can be applied substantially tangentially to core portion 102, parallel to a major surface of the core portion (e.g., core surface 124A or core surface 124B). As such, dimples shaped and oriented so that dimple walls 138 have a high surface area facing the direction of the braking force can distribute the received force over a larger surface area.

[0081] The plurality of dimples 110 can have a variety of configurations and patterns. In some examples, the number and / or tangential surface area corresponds to the magnitude of the force received from the radial distance from the center of the core portion 102. In some examples, the plurality of dimples 110 can be symmetrical in at least one plane. In some examples, each dimple in the plurality of dimples 110 can be located at the same radial distance from the center of the core portion 102, so that each dimple in the plurality of dimples 110 can then receive the same torque. In some examples, the plurality of dimples 110 can be located at different radial distances from the center of the core portion 102.

[0082] The core portion 102 may be made of a variety of materials, including but not limited to metals such as aluminum, stainless steel, and titanium alloys. In some examples, the core portion 102 may be made of one or more materials that can be refurbished, such that the service life of the core portion 102 may be substantially longer than that of the friction pads 104 .

[0083] In some examples, core portion 102 may be made of a material having high strength, particularly in the circumferential direction. For example, as described above, core portion 102 may be configured to receive braking forces from friction pad 104. Thus, core portion 102 may be made of a material having high strength to withstand the various forces generated on the core portion due to the received braking forces. In some examples, core portion 102 has high strength (in tension, compression, and / or shear) at the high temperatures experienced during braking.

[0084] In some examples, core portion 102 may be made of a material capable of receiving and / or storing large amounts of heat. For example, as described above, core portion 102 may be configured to receive heat from friction pad 104. Therefore, core portion 102 may be made of a material having a high specific heat capacity to receive large amounts of heat and / or other thermal properties such as high heat dissipation or high thermal diffusivity. In some examples, core portion 102 includes a material having a specific heat capacity greater than 200 J / kg·K, such as greater than 475 J / kg·K, at room temperature. For example, tungsten carbide may have a specific heat capacity greater than 200 J / kg·K, steel may have a specific heat capacity greater than 475 J / kg·K, and boron nitride may have a specific heat capacity greater than 1500 J / kg·K. In some examples, core portion 102 includes a material having a thermal conductivity greater than 7 W / m·K, such as greater than 20 W / m·K, at room temperature. For example, a titanium alloy may have a thermal conductivity greater than 7 W / m·K. In some examples, structural core 102 comprises a material having a thermal conductivity greater than carbon (approximately 23 W / m·K).

[0085] In some examples, the core portion 102 can be manufactured by relatively simple manufacturing processes such as cutting (e.g., milling, drilling) and casting (e.g., die casting) processes. For example, structural features of the core portion 102, such as the plurality of dimples 110 and the edge 136, can involve relatively simple geometries (e.g., substantially square angles between the core surface 124 and the dimple walls 138) that are relatively simple to manufacture. Therefore, standard machining and manufacturing processes applicable to these simple geometries can be used to manufacture the core portion 102 more quickly and / or at a low cost. Additionally or alternatively, such simple geometries can allow for easier refurbishment or repair of the core portion 102, so that the service life of the core portion 102 can be extended more easily and / or at a low cost.

[0086] Figure 4D 1 is a schematic cross-sectional side view of an exemplary friction pad 104 according to an example of the present disclosure. The friction pad 104 includes a pad surface 115 and a friction surface 112 opposite the pad surface 115. The pad surface 115 includes a flat pad surface 114 and a land surface 118 of each of a plurality of lands 116 extending from the flat pad surface 114. The flat pad surface 114 is configured to contact and thermally interface with one of the core surfaces 124.

[0087] Each boss of the plurality of bosses 116 is configured to engage with a dimple of the plurality of dimples 110 of the core portion 102 to position the corresponding friction pad 104 relative to the core portion 102. For example, each boss of the plurality of bosses 116 may have a size or shape that is complementary to a dimple of the plurality of dimples 110. During attachment of the friction pad 104 to the core portion 102, the plurality of bosses 116 may fit into the dimples 110 of the core portion 102 so that the friction pad 104 may be quickly and / or easily positioned relative to the core portion 102.

[0088] The friction pad 104 is configured to transfer braking force or torque to the core portion 102 via a plurality of bosses 116. Each boss of the plurality of bosses 116 is configured to be received by a dimple of the plurality of dimples 110 of the core portion 102 and includes a boss wall 134 that intersects the plane of the planar pad surface 114. During braking, at least a portion of the boss wall 134 is configured to contact at least a portion of a corresponding dimple wall 138 when the plurality of bosses 116 engage the plurality of dimples 110, such that at least a portion of the boss wall 134 can transfer a portion of the braking force to the dimples of the core portion 102. In this way, a braking force can be applied to the core portion 102 via the surface area of ​​the boss walls 134 of the plurality of bosses 116.

[0089] In addition to transferring braking forces, the friction pad 104 is configured to convert kinetic energy into thermal energy and transfer at least a portion of the thermal energy to the core portion 102 via the pad surface 114. The flat pad surface 114 is configured to contact a core surface 124 of the core portion 102. The contact between the core surface 124 and the flat pad surface 114 can provide thermal conduction of heat generated by the friction surface 112 of the friction pad 104 to the corresponding core surface 124. In some examples, the thermal contact between the core portion 102 and the friction pad 104 can be expressed as a portion (e.g., a percentage) of the total surface area of ​​the friction pad 104 that is configured to contact the core portion 102 (e.g., the flat pad surface 114). The flat pad surface 114 comprises at least approximately 50% of the surface area of ​​the pad surface 115. In some examples, the flat pad surface 114 comprises at least approximately 70%, such as at least approximately 95%, of the surface area of ​​the pad surface 115.

[0090] The friction pad 104 is configured to be secured to the core portion 102 using fasteners, such as fastener 108. Each of the plurality of bosses 116 includes a hole 106. The hole 106 is configured to receive the fastener 108 and pass the fastener 108 through to a structure on an opposite side of the core portion 102, such as another friction pad 104 in a two-side disc brake in the middle of the brake disc stack 16 or a support structure in a one-side disc brake at the end of the brake disc stack 16.

[0091] In some examples, the friction pad 104 can be configured to have an increased usable depth of the friction surface 112 over the life of the friction pad 104 by recessing the holes 106. For example, the depth of the friction surface 112 can be limited by a closer core surface 124 of the core portion 102 (e.g., closer to the friction surface 112) or by the fasteners 108 in the holes 106, such that by recessing the holes 106, the fasteners 108 may not limit the depth of the friction surface 112. In some examples, the inner bore surface 122 of each hole 106 extends a recess distance 128 beyond the plane of the flat pad surface 114. In some examples, the recess distance 128 is greater than the head height of the fasteners 108, such as greater than approximately 0.1 inches. During use, the friction surface 112 of the friction pad 104 may not wear the fasteners 108, allowing the friction pad 104 to remain secured to the core portion 102. In some examples, a thickness 132 of edge 136 between edge surface 126 and flat core surface 124 is approximately a thickness 130 of friction pad 104 between friction surface 112 and flat pad surface 114 , where thickness 130 represents the usable depth of friction surface 112 over the life of friction pad 104 .

[0092] The friction pad 104 may be in the shape of a disk or annulus defining a preformed outer diameter (OD) and a preformed inner diameter (ID). In some examples, the outer diameter (OD) of the friction pad 104 may be approximately 12 inches (e.g., approximately 37 cm) to approximately 25 inches (e.g., approximately 64 cm), and the preformed inner diameter (ID) of the friction pad 104 may be approximately 4.5 inches (e.g., approximately 12 cm) to approximately 15 inches (e.g., approximately 38 cm).

[0093] The plurality of lands 116 may be configured to have a size, orientation, and distribution based on various factors, including, but not limited to, thermal expansion of the lands and / or dimples, bearing area of ​​the lands and / or dimples, shear area of ​​the lands and / or dimples, surface area of ​​each dimple, surface area of ​​the plurality of dimples, ratio of tangential surface area (e.g., surface area of ​​each land in a direction tangential to the direction of rotation of the friction pad 104 ) to axial surface area, etc. The plurality of lands 116 may have a size, orientation, or distribution that complements the plurality of dimples 110 .

[0094] The plurality of bosses 116 can have a variety of sizes and dimensions. In some examples, each boss in the plurality of bosses 116 has a circumferential dimension between about 0.25 inches and about 12 inches (e.g., measured from the center of each boss along an arc of rotation parallel to the direction of rotation of the friction pad 104). In some examples, each boss in the plurality of bosses 116 has a radial dimension between about 0.25 inches and about 8 inches (e.g., measured from the center of each dimple in a radial direction from the center of the friction pad 104).

[0095] The plurality of bosses 116 may have a variety of shapes corresponding to the shapes of the plurality of dimples 110 of the core portion 102, including but not limited to rectangular, rounded rectangular, circular, wedge-shaped, etc. In some examples, the plurality of bosses 116 may have a shape and orientation with a high tangential surface area. For example, Figure 4A As shown, a braking force can be applied substantially tangentially to core portion 102. As such, bosses shaped and oriented such that boss walls 134 have a high surface area facing the direction of the braking force can transfer the force to a larger surface area. In some examples, each boss surface 118 is configured to contact a corresponding boss surface 118 of another boss in the second plurality of bosses of another friction pad when the plurality of bosses 116 and the second plurality of bosses engage the plurality of dimples 110. As such, the plurality of bosses of two opposing friction pads can extend through the corresponding dimples 110 and contact substantially the entire inner surface of the corresponding dimple 110.

[0096] The plurality of lands 116 can have a variety of configurations and patterns. In some examples, the number and / or tangential surface area corresponds to the amount of force received at a radial distance from the center of the friction pad 104. In some examples, the plurality of dimples 116 can be symmetrical in at least one plane. In some examples, the plurality of dimples 116 can have the same radial distance from the center of the friction pad 104, such that each of the plurality of lands 116 can transfer substantially the same torque. In some examples, the plurality of lands 116 can have different radial distances from the center of the friction pad 104.

[0097] In some examples, the friction pads 104 are cross-compatible with both rotor brake discs and stator brake discs. For example, the rotor, stator, and end plate can use the same friction pads 104 attached to different styles of core segments 102. As long as the plurality of dimples 110 of each core segment 102 for the stator, rotor, or end plate corresponds to the plurality of bosses 116 of the friction pads 104, such friction pads can be used with the corresponding core segment 102, even if the design of the other segments of the core segment 102 is different. Such cross-compatibility can reduce the number of parts to be manufactured, which can reduce inventory and allow for cheaper manufacturing.

[0098] The friction pad 104 may be manufactured from a carbon-carbon composite material. In some examples, the friction pad 104 may be manufactured from a carbon-carbon composite material having high thermal stability, high wear resistance, and / or stable friction characteristics. For example, as described above, the friction pad 104 is configured to convert kinetic energy into thermal energy. Therefore, the friction pad 104 may be manufactured from a carbon-carbon composite material having high thermal stability to withstand high temperatures. In some examples, the friction pad 104 includes a material having an operating temperature threshold greater than approximately 1100°C, such as greater than approximately 1700°C. For example, carbon can withstand operating temperatures greater than approximately 1725°C.

[0099] As described herein, the friction pad 104 may be formed of a carbon-carbon composite material made of a dense carbon material. In some examples, the carbon material may include a variety of carbon fibers and dense materials. The carbon fibers may be composed of carbon or a carbon precursor material such as polyacrylonitrile (PAN) or rayon, which may be converted into carbon by a carbonization process. The carbon fibers used to form the friction pad 104 may be arranged in a woven or non-woven fabric as either a single layer or a multilayer structure. In some examples, a carbon-carbon composite material customized for improved friction may include non-woven carbon fibers and a reinforcing material (e.g., carbonized asphalt or resin). Compared to a woven structure, a non-woven structure of a carbon fiber matrix may improve the resulting friction characteristics of the friction pad 104.

[0100] Figure 5 is a flow chart illustrating an example technique for assembling an example brake rotor assembly 100 according to examples of the present disclosure. Figure 5 Will refer to Figures 4A-4D However, it should be understood that Figure 5 The techniques may be used to assemble other articles, such as the brake rotor assembly 50 or the brake rotor assembly 70 . Figure 5 The disclosed technique includes positioning a first plurality of bosses 116A of a first friction pad 104A into a plurality of dimples 110 of a core portion 102 such that the first planar pad surface 114A contacts the first core surface 124A, and positioning a second plurality of bosses 116B of a second friction pad 104B into the plurality of dimples 110 of the core portion 102 such that the second planar pad surface 114B contacts the second core surface 124B. Figure 5 The technique further includes passing the plurality of elongated fasteners 108 through the first apertures 106A of a corresponding one of the first plurality of bosses 116A and the second apertures 106B of a corresponding one of the second plurality of bosses 116B. Figure 5 The technique also includes securing a plurality of elongated fasteners 108 to fasten the first friction pad 104A and the second friction pad 104B to the core portion 102 .

[0101] Various examples have been described. These and other embodiments are within the scope of the following claims.

Claims

1. A brake disc assembly, comprising: a single continuous core portion defining a core of said brake disc assembly; and a friction portion adjacent to the core portion, the friction portion defining a friction surface of the brake disc assembly during a braking operation, wherein the friction portion comprises a carbon-carbon composite material, wherein the core portion comprises a core material that is not a carbon-carbon composite material, and wherein the core portion is configured as a heat sink for the brake disc assembly for heat generated during the braking operation, wherein the core portion is coupled to the friction portion via a plurality of boss assemblies, each boss assembly being positioned within a corresponding aperture in the core portion such that a projection protrudes out of a surface plane of the core portion, and the projections mate with corresponding groove-like recesses in an opposing surface of the friction portion.

2. The assembly of claim 1, wherein the core material comprises at least one of steel, tungsten carbide, boron nitride, boron carbide, silicon nitride, or silicon carbide.

3. A method for forming a brake disc assembly, the method comprising: A single continuous core portion is positioned adjacent to the friction portion using a plurality of boss assemblies between the core portion and the friction portion, each boss assembly being positioned within a corresponding aperture in the single continuous core portion such that a protruding portion protrudes out of a surface plane of the core portion and the protruding portions mate with corresponding groove-like recesses in an opposing surface of the friction portion, wherein the core portion defines a core of the brake disc assembly, wherein the friction portion defines a friction surface of the brake disc assembly during a braking operation, wherein the friction portion comprises a carbon-carbon composite material, wherein the core portion comprises a core material that is not a carbon-carbon composite material, and wherein the core portion is configured as a heat sink for the brake disc assembly for heat generated during the braking operation.

Images