piston cover

Abstract

The invention is entitled a piston cover. A brake system is disclosed that in some examples includes a piston configured to cause compression of a stack of discs. The piston includes a piston body configured to compress a cover face of a piston cover against a pressure plate to cause compression of the stack of discs. The cover face can define a convex surface. The piston cover can be configured such that the convex surface decreases its curvature when the cover face is compressed against the pressure plate. In examples, the piston cover is configured to elastically deform when the cover face is compressed against the pressure plate to cause the cover face to decrease the curvature.

Description

Technical Field

[0001] This disclosure relates to piston caps for pistons, such as piston caps for brake disc assemblies in wheel brake systems for compression vehicles. Background Technology

[0002] Vehicles such as aircraft may use wheel braking systems that include multi-disc braking systems. For example, a multi-disc braking system may include multiple rotors engaged with the wheel and multiple stators interleaved with the rotors. The rotors and wheel are configured to rotate about an axis, while the stators remain stationary. To slow the rotational motion of the rotating wheel, the braking system may displace a piston against a pressure plate to compress the rotating rotor engaged with the wheel against the stationary stator, thereby generating a torque that slows the rotational motion of the wheel. In some examples, the piston may cause its cap to compress against the pressure plate. Summary of the Invention

[0003] In some examples, this disclosure describes articles, systems, and techniques related to braking systems for vehicles. The braking system may include a stack of discs configured to reduce and / or prevent wheel rotation when the stack is compressed. The braking system may include a piston configured to translate a pressure plate to cause compression of the stack of discs. The piston (e.g., a piston cap) may define a convex surface configured to reduce its curvature (e.g., substantially flatten) when the piston is compressed against the pressure plate. As the convex surface reduces its curvature, the deformation of the piston can help transfer compressive forces from the piston to the pressure plate, thereby protecting the pressure plate disc from, for example, the high mechanical stresses experienced by the pressure plate during braking operation of the braking system.

[0004] In one example, this disclosure relates to a braking system comprising: a pressure plate defining a contact surface, wherein the pressure plate is configured to compress a disc stack of the braking system; and a piston configured to cause the pressure plate to compress the disc stack, the piston comprising: a piston body configured to translate along a piston axis; and a piston cap defining a cap surface intersecting the piston axis and defining a periphery around the piston axis, wherein the cap surface defines an inner surface segment intersecting the piston axis, an outer surface segment adjacent to the periphery, and an intermediate surface segment between the inner surface segment and the outer surface segment, wherein the intermediate surface segment defines a convex surface defining a curvature, wherein the piston body is configured to abut against the contact surface of the pressure plate to compress the cap surface to cause the pressure plate to compress the disc stack, and wherein the convex surface is configured to reduce the curvature when the piston body abuts against the contact surface to compress the cap surface.

[0005] In another example, this disclosure relates to a braking system comprising: a pressure plate defining a contact surface, wherein the pressure plate is configured to compress a disc stack of the braking system; and a piston defining a piston axis and configured to cause the pressure plate to compress the disc stack, the piston comprising: a piston cap defining a cap face intersecting the piston axis and a rear face opposite the cap face, wherein the cap face defines a periphery surrounding the piston axis, and the rear face defines a rear periphery surrounding the piston axis, wherein the cap face defines an inner surface segment intersecting the piston axis, an outer surface segment adjacent to the periphery, and a rear surface segment adjacent to the piston axis. and an intermediate surface section between the inner surface section and the outer surface section, wherein the intermediate surface section defines a convex surface that defines curvature; and a piston body configured to translate along a piston axis, wherein the piston body and the rear side define a piston cavity intersecting the piston axis, wherein the piston body is configured to apply force on its rear periphery to abut against a contact surface of a pressure plate to compress the cover, wherein the piston cover is configured such that when the piston body abuts against the contact surface to compress the cover, a concave surface reduces curvature, and wherein abutting against the contact surface to compress the cover causes the pressure plate to stack.

[0006] In another example, this disclosure relates to a method comprising: translating a piston body of a piston toward a contact surface of a pressure plate along a piston axis defined by the piston; translating a piston cap having a cover toward the contact surface using the translation of the piston body, the cover defining an inner surface segment intersecting the piston axis, an outer surface segment adjacent to the periphery of the cover, and an intermediate surface segment between the inner and outer surface segments, wherein the intermediate surface segment defines a convex surface defining a curvature; reducing the curvature of the convex surface by compressing the cover against the contact surface using the piston body; and compressing the stacked discs using the pressure plate while the cover is compressed against the contact surface.

[0007] Details of one or more examples are set forth in the accompanying drawings and the following description. Other features, objects, and advantages will be apparent from the description and drawings, as well as from the claims. Attached Figure Description

[0008] Figure 1 This is a perspective view showing an exemplary wheel that includes multiple rotor drive keys on the inner surface of the wheel.

[0009] Figure 2 It includes Figure 1 A schematic cross-sectional view of an exemplary wheel and brake system.

[0010] Figure 3 This is a schematic diagram showing an exemplary piston and pressure plate of a braking system.

[0011] Figure 4 It shows the support Figure 3A schematic diagram of an exemplary piston compressed by a pressure plate.

[0012] Figure 5A yes Figure 3 and Figure 4 A schematic diagram of the piston.

[0013] Figure 5B yes Figure 5A A schematic diagram of the piston.

[0014] Figure 6 This is a schematic diagram of the piston cap.

[0015] Figure 7 This is a flowchart illustrating an exemplary technique for compressing disk stacks. Detailed Implementation

[0016] This disclosure describes articles, systems, and techniques relating to a piston in a disc stack configured to compress a wheel brake system of a vehicle. The disc stack can be configured to compress between a pressure plate and a backing plate, or another part of the brake system. The piston described herein can be configured to apply a compressive force to the pressure plate to cause the pressure plate to translate toward the disc stack, thereby causing compression of the disc stack. Compression of the disc stack can lead to engagement of friction surfaces on the brake disc, thereby reducing and / or preventing rotation of the vehicle wheels.

[0017] In some examples, the piston includes a piston cap defining a cover surface. The piston is configured to compress the cover surface against the contact surface of the pressure plate to cause translation of the pressure plate and compression of the disc stack. The piston may be configured to translate along the piston axis to compress the cover surface against the contact surface. The cover surface is configured to deflect upon compression against the pressure plate, such that the cover surface distributes the compressive force more evenly across the contact surface of the pressure plate. The piston cap may be configured to deform upon compression against the pressure plate, such that, for example, the cover surface distributes the compressive force transmitted from the piston to the pressure plate. A more even distribution reduces stress concentration during compression, thereby reducing wear and / or damage to the pressure plate contact surface that may occur during repeated braking operations. Reduced stress concentration extends the life of the pressure plate, piston, or other components of the braking system.

[0018] In some braking systems, the way forces are transmitted from the piston cap to the pressure plate, for example, the compressive force applied by the piston against the pressure plate often results in specific wear and / or damage patterns on the pressure plate. In some cases, the piston cap may undergo a degree of buckling under transmitted load, resulting in a highly uneven stress distribution on the cap surface during compression. This uneven stress distribution can cause significant variations in the magnitude of the forces transmitted to the pressure plate at various points on the cap surface, leading to large stress concentrations on the pressure plate when the cap is compressed. For example, in systems where the cap surface transmits the compressive forces generated by the substantially tubular piston body pushing against the pressure plate, the cap surface can deform under load, causing a significant portion of the compressive force to be transmitted through annular areas on the cap surface, or manifesting in some other pattern. These localized force variations caused by the deformation of the piston cap under load can accelerate damage and / or failure of the pressure plate's contact surfaces. For example, when the pressure plate's contact surfaces include relatively brittle layers such as antioxidant coatings, localized force variations can cause the brittle layers to fracture, thereby reducing and / or essentially eliminating the antioxidant properties of the coating. The deflection and / or deformation of the piston cap described herein can result in a more efficient distribution of forces transmitted through the cap surface, causing a more distributed stress distribution on the contact surface of the pressure plate as the cap surface presses against it.

[0019] The piston cap can be configured to deform when the cap surface is compressed against a pressure plate. The cap surface may define a convex surface that defines a curvature, wherein the cap surface is configured such that the convex surface reduces its curvature when it contacts the pressure plate. The deformation of the cap surface caused by the reduction in curvature can be used to more effectively distribute the transmitted load across the entire cap surface. In an example, the piston cap's cap surface defines an inner surface segment that intersects and / or is closest to a piston axis intersecting the cap surface, an outer surface segment adjacent to the periphery defined by the cap surface, and an intermediate surface segment substantially between the inner and outer surface segments. The intermediate surface segment can be configured to substantially bend away from the contact surface of the pressure plate (e.g., defining convexity) when the cap surface is in a relaxed state (e.g., when the cap surface is displaced from the pressure plate). The piston cap can be configured such that the bent intermediate surface segment substantially deflects to contact the pressure plate during compression against the pressure plate. When the cap is compressed, the deflection of the middle surface section causes the piston cap to distribute the compressive force applied by the piston against the pressure plate more evenly, thereby reducing stress concentration on the contact surface of the pressure plate during compression. Therefore, the piston cap can be configured to substantially deform under load from the piston, so that the piston cap is used to distribute the transmitted load more evenly across the entire cap surface.

[0020] In some examples, the inner surface segment is the region of the cap surface that intersects with and / or is closest to the piston axis intersecting the cap surface. The inner surface segment can be, for example, a substantially circular, elliptical, or oval region. The intermediate surface segment can substantially surround and / or be located near the inner surface segment. In an example, the intermediate surface segment defines a first ring (e.g., a first toroidal surface) surrounding the inner surface segment. The outer surface segment is adjacent to the perimeter defined by the cap surface and can substantially surround and / or be located near the intermediate surface segment. In an example, the outer surface segment can substantially surround both the intermediate surface segment and the inner surface segment. In an example, the outer surface segment defines a second ring (e.g., a second toroidal surface) surrounding both the intermediate surface segment and the inner surface segment.

[0021] The piston cap can be configured such that when the cap is in a substantially relaxed state (e.g., displaced from the pressure plate), at least the intermediate surface section bends away from the contact surface. The cap can be configured such that when the inner surface section contacts the contact surface, the intermediate surface section deflects to contact the contact surface when the piston compresses the cap against the pressure plate. The piston cap can deform under piston load to cause the intermediate surface section to deflect. In the example, the piston cap is configured such that the resulting deformation causes the piston cap to distribute the force transmitted from the piston substantially across the entire cap surface, resulting in a more uniform distribution of the force transmitted by the piston cap to the contact surface of the pressure plate. Additionally, the piston cap can be configured such that deformation reduces and / or substantially eliminates buckling of the piston cap under piston load, so that the compression of the cap against the pressure plate substantially avoids stress concentration, which could shorten the service life of the pressure plate.

[0022] The piston cap may include a concave surface on the cap surface. The concave surface may define a second curvature, wherein the cap surface is configured to reduce the second curvature when it contacts the pressure plate. In some examples, an outer surface segment of the cap surface defines the concave surface. The piston cap may be configured such that the outer surface segment defines the concave surface when the cap surface is in a relaxed state (e.g., displaced from the pressure plate). The concavity of the outer surface segment may cause deformation of the piston cap such that when the piston cap transfers compressive force from the piston to the pressure plate, the compressive force of the piston is more effectively distributed across the entire cap surface. In an example, the piston cap is configured such that when the piston cap is in a relaxed state (e.g., displaced from the pressure plate), an intermediate surface segment defines convexity and an outer surface segment defines concavity.

[0023] As used herein, a convex surface or convexity of the cover can refer to a portion of the surface that has positive curvature relative to a vector perpendicular to and extending from that portion of the surface. A concave surface or concavity can refer to a portion of the surface that has negative curvature relative to a vector extending from and perpendicular to that portion of the surface. In one example, when the piston is configured to press against the contact surface against the cover, a vector perpendicular to and extending away from the surface has a direction from the cover toward the contact surface of the pressure plate. When the surface reduces its curvature, or when another part of the cover or braking system causes the surface to reduce its curvature, this can refer to a surface that increases some or substantially all of its radius of curvature. The surface can be convex or concave.

[0024] In the example, the piston cap defines a back face opposite to the cap face. The piston may define a piston body mechanically engaged (e.g., attached to) the back face. The piston body may be configured to apply a compressive force on the back face, causing the piston cap to translate toward the pressure plate. The piston body may apply a compressive force such that the piston cap compresses against the pressure plate and transmits the compressive force to the pressure plate. In the example, the piston body applies a compressive force on the back face of the piston cap and causes the piston cap to deform against the pressure plate, such that when the piston cap transmits the compressive force to the pressure plate, the piston cap distributes the compressive force on the cap surface. The piston body may be configured to apply a compressive force on the back face, such that, for example, the cap face applies at least a portion of the compressive force to the pressure plate, thereby translating the pressure plate and compressing the disc stack in the braking system. In the example, the piston axis may intersect the cap face, the back face, and / or the piston body. In some examples, the piston body is mechanically engaged with the piston cap such that the back face and the piston body define a cavity within the piston. For example, the piston body may be a substantially tubular member that defines a piston wall and is configured such that the piston wall applies compressive force around a rear perimeter defined by a rear side.

[0025] The piston cap may define the thickness between the back surface and the cap surface. In the example, the thickness is defined in a direction substantially parallel to the piston axis. The piston cap may be configured such that the thickness defined at a first point on the cap surface differs from the thickness defined at a second point on the cap surface. For example, the piston cap may be configured such that the change in thickness contributes to the distribution of compressive force when the piston cap deforms by compression against a pressure plate. In some examples, the thickness at a point defined on the inner surface segment is less than the thickness at a point defined on the intermediate surface segment and / or the outer surface segment. In some examples, the thickness increases with increasing distance from the piston axis (e.g., increasing in a direction from the piston axis toward the periphery of the piston cap).

[0026] Therefore, the piston cover can be configured to substantially reduce stress concentration on the contact surface of the pressure plate when the piston cover causes pressure plate translation during braking operation of the braking system. The piston cover can be configured to deform and / or deflect when the cover surface is compressed against the pressure plate, such that the piston cover effectively distributes the compressive force applied by the piston body across the cover surface. The deformation and / or deflection of the piston cover can lead to a more efficient distribution of forces transmitted to the pressure plate through the cover surface, resulting in a more distributed stress distribution on the pressure plate. This distributed stress distribution can limit and / or substantially avoid stress concentration that shortens the service life of the pressure plate within the wheel's braking system.

[0027] Figure 1 This is a perspective view showing an exemplary wheel 10 configured to rotate about axis A. In some examples, wheel 10 is part of an aircraft vehicle. In other examples, wheel 10 may be part of any other vehicle, such as any land vehicle or other vehicle. Figure 1 In the example shown, wheel 10 includes a wheel rim 12 defining an outer surface 14 and an inner surface 16. Wheel rim 12 includes a well 18 and a wheel hub 20. The inner surface 16 and wheel hub 20 may define a wheel cavity 22 (e.g., a volume) between the inner surface 16 and the wheel hub 20. In some examples, a tire (not shown) may be mounted on the outer surface 14 of rim 12. A plurality of rotor drive keys 32, including rotor drive keys 34 and 36, may be mounted on and / or integrally formed with the inner surface 16 of wheel 10 such that each rotor drive key translates about axis A in a closed path as wheel 10 (and inner surface 16) rotates about axis A. Rotor drive keys 32 may be configured to receive torque from a braking system (not shown) configured to reduce and / or stop the rotation of wheel 10.

[0028] Figure 2 This is a schematic cross-sectional view showing a wheel 10 and an exemplary braking system 40. The wheel 10 includes a wheel rim 12, an outer surface 14, an inner surface 16, a wheel cavity 22, a wheel hub 20, and a rotor drive key 34. The wheel 10 and the braking system 40 are shown and described to provide context for the exemplary piston and / or piston cover described herein. However, in other examples, the piston and / or piston cover described herein can be used with any system.

[0029] The axis A of wheel 10 extends through axial assembly 46. Axis assembly 46 is configured to support wheel 10 while allowing wheel 10 to rotate about axis A using bearings 48 and 50. For example, bearings 48 and 50 may define a substantially circular track around axial assembly 46. Torque tube 52 is coupled to axial assembly 46 (e.g., via bolts 54 and 56) such that torque tube 52 remains substantially stationary as wheel 10 rotates about axial assembly 46 and axis A. Torque tube 52 may at least partially surround the exterior of axial assembly 46. Axis assembly 46 may be mechanically coupled to a structure attached to a vehicle (e.g., a strut).

[0030] exist Figure 2 In the example shown, brake system 40 is positioned within wheel cavity 22 and configured to engage torque tube 52 and rotor drive key 34. Brake system 40 is configured to generate torque to resist rotation of wheel 10 about axis A and transmit that torque to rotor drive key 34, thereby reducing and / or eliminating rotation of wheel 10 about axis A. Brake system 40 includes a disc stack 58 comprising one or more rotor discs (e.g., rotor discs 60, 61, 62, 63) and one or more stator discs (e.g., stator discs 64, 65, 66). Rotor discs 60, 61, 62, 63 and / or stator discs 64, 65, 66 may have any suitable configuration. For example, rotor discs 60, 61, 62, 63 and / or stator discs 64, 65, 66 may be substantially annular discs surrounding torque tube 52. Stator discs 64, 65, and 66 are connected to torque tube 52 via key 68 and remain stationary relative to torque tube 52 as wheel 10 rotates. Rotor discs 60, 61, 62, and 63 are rotatably connected to rotor drive key 34 and rotate substantially synchronously with wheel 10 about axis A. Disc stack 58 may include any number of rotor and stator discs.

[0031] Rotor disks 60, 61, 62, 63 and / or stator disks 64, 65, 66 may be configured to provide opposing friction surfaces for braking vehicles such as aircraft. Compression of the disk stack 58 (e.g., between pressure plate 70 and backing plate 72) brings the opposing friction surfaces into contact, thereby generating a shear force between the rotor disks rotating substantially synchronously with the wheel 10 and the stator disks remaining substantially stationary relative to the torque tube 52. The shear force can cause the rotor disks (e.g., rotor disks 60, 61, 62, 63) engaging with the rotor drive key 34 to apply a torque opposite to the rotation of the wheel 10 on the rotor drive key 34.

[0032] An actuator 74, including an actuator body 78, is configured to cause a piston 76 to translate relative to the actuator body 78 to compress a disc 58. The piston 76 includes a piston body 80 and a piston cap 82. In an example, the piston body 80 is configured to translate such that the piston cap 82 applies a compressive force to a pressure plate 70, thereby causing the pressure plate 70 to translate in a direction substantially parallel to axis A. The braking system 40 is configured such that the translation of the pressure plate 70 compresses the disc stack 58 between the pressure plate 70 and the backing plate 72, thereby engaging the friction surfaces of the rotor discs 60, 61, 62, 63 and the stator discs 64, 65, 66 to reduce and / or substantially prevent rotation of the wheel 10. The actuator 74 can cause the piston 76 to translate using any suitable method. In some examples, the actuator 74 is configured to cause the translation of the piston 76 by supplying and / or discharging pressurized hydraulic fluid from the piston chamber. Alternatively or conversely, in some examples, actuator 74 is configured to cause piston 76 to translate by a motion (e.g., rotational motion) generated by an electric motor. Braking system 40 may include additional actuators, such as actuator 75 configured to cause piston 77 to translate to apply a compressive force on pressure plate 70. In one example, braking system 40 includes a plurality of actuators and a plurality of pistons arranged about axis A and configured to apply a compressive force on pressure plate 70.

[0033] The piston body 80 is configured to apply a compressive force to the piston cap 82, causing the piston cap 82 to compress against the pressure plate 70. The piston cap 82 is configured to transmit the compressive force from the piston body 80 to the pressure plate 70, thereby causing compression of the disc stack 58 and braking of the wheel 10. The piston cap 82 may include a cover surface 84 configured to contact the pressure plate 70 when the piston cap 82 transmits the compressive force to the pressure plate 70. The cover surface 84 may be configured to compress against a contact surface 86 of the pressure plate 70 when the piston cap 82 transmits the compressive force to the pressure plate 70. The compression of the cover surface 84 against the contact surface 86 and the transmission of the compressive force from the piston body 80 to the pressure plate 70 create a stress distribution across the contact surface 86 and within the pressure plate 70. In an example, the contact surface 86 may be defined by a relatively brittle portion of the pressure plate 70, such as an antioxidant coating. For example, the contact surface 86 may be defined by a coating comprising phosphate glass.

[0034] The piston cap 82 may be configured to deform when the cap surface 84 is compressed against the contact surface 86. This deformation causes the piston cap 82 to distribute the compressive forces from the piston body 80 more evenly across the entire cap surface 84. The piston cap 82 may define a convex surface on the cap surface 84, which is configured to substantially reduce its curvature when the piston cap 82 is compressed against the contact surface 86 of the pressure plate 70. In some examples, the piston cap 82 defines a concave surface that defines a second curvature on the piston cap 82, wherein the concave surface is configured to reduce the second curvature when compressed against the contact surface 86. The distribution of compressive forces across the entire cap surface 84 caused by the deformation of the piston cap 82 can reduce stress concentration generated within the pressure plate 70, thereby potentially extending the service life of the pressure plate 70. In the example, the contact surface 86 is defined by a relatively brittle portion of the pressure plate 70 (e.g., an antioxidant coating). When the cover 84 is compressed against the contact surface 86, the deformation of the piston cover 82 can more effectively distribute the compressive force over the area of ​​the contact surface 86, thereby reducing and / or eliminating the fracture of brittle materials during braking operation of the brake system 40.

[0035] Wheel 10 and braking system 40 can be used with any kind of private, commercial, or military aircraft or other type of vehicle. Wheel 10 can be mounted to the vehicle using, for example, bolts 54 and / or bolts 56 or some other fastening device. Axis assembly 46 can be mounted on a strut of landing gear (not shown) or other suitable component of the vehicle to connect wheel 10 to the vehicle. Wheel 10 can rotate about axis A and axial assembly 46 to apply motion to the vehicle. Wheel 10 has been shown and described to provide context for the braking system described herein; however, in other examples, the braking system described herein can be used with any suitable wheel assembly.

[0036] Figure 3 and Figure 4 This is a schematic diagram of an exemplary portion of a brake system 40 including a piston 76 and a pressure plate 70. The piston 76 includes a piston body 80, a piston cap 82, a cap surface 84, and a back surface 85 opposite to the cap surface 84. The piston axis P intersects the cap surface 84. Figure 3 The piston cap 82 is shown in a relaxed state and has been displaced from the pressure plate 70. Figure 4 The piston cap 82 is shown in a deformed state caused by compression of the piston cap 82 against the contact surface 86. The piston cap 82 can be configured such that the cap surface 84 is compressed against the contact surface 86 due to the compressive force F applied to the piston cap 82 by the piston body 80. Figure 3 and Figure 4In the diagram, the piston body 80 and piston cap 82 are shown as cross-sections, with the cutting plane parallel to the page. The piston body 80 is depicted as a substantially tubular member, wherein the piston wall 88 at least partially surrounds the piston axis P and defines an inner piston surface 90 facing the piston axis P and an outer piston surface 92 on the opposite side of the piston wall 88. In other examples, the piston body 80 may define other shapes.

[0037] The piston cap 82 is configured to define a convex surface on the cap surface 84 when the piston cap 82 is in a relaxed state (e.g., displaced from the pressure plate 70). The convex surface may define a curvature. In the example, the curvature of the convex surface (or a portion of the convex surface) has an inverse relationship with the radius of curvature, where the radius of curvature is the radius of the circle that best fits the curvature defined by the convex surface. The convex surface may be configured such that when the curvature of the convex surface decreases, the radius of curvature increases.

[0038] In the example, piston cap 82 defines a convex surface such that cap surface 84 is substantially curved away from contact surface 86 in a relaxed state. For example, when piston cap 82 is in a relaxed state, piston cap 82 may define a portion of cap surface 84 with a positive curvature relative to a vector v1 perpendicular to and extending from cap surface 84. Piston cap 82 may be in a relaxed state in the absence of a steady-state compressive force F applied by piston body 80 to piston cap 82 and compressing piston cap 82 against pressure plate 70. In the example, when piston cap 82 is in a relaxed state, piston cap 82 is in a substantially zero-stress position, where any stress on piston cap 82 is caused by characteristics or phenomena within bridging member 450, such as mass, internal temperature, residual stress (e.g., from manufacturing and / or mechanical attachment to another component), etc.

[0039] In the example, plane P1 perpendicular to vector v1 and plane P2 perpendicular to piston axis P define an angle θ1 between P1 and P2, and the convex surface of cover 84 is defined such that angle θ1 increases in the direction from piston axis P to perimeter 89 defined by cover 84. Plane P2 may be substantially parallel to a portion of contact surface 86 of pressure plate 70. Piston 82 may be configured such that angle θ1 decreases (e.g., decreases to substantially zero degrees) when cover 84 is compressed against contact surface 70. In other examples, piston 82 may be configured such that angle θ1 decreases to a value greater than substantially zero degrees.

[0040] The piston cap 82 can be a substantially elastically deformable element that exhibits a shape change when a compressive force F is applied against the contact surface 86 to compress the cap surface 84, and substantially reverses the shape change when the compressive force F is removed (e.g., when the cap surface 84 displaces from the contact surface 86). The compressive force F can depend on the pressure between the cap surface 84 and the contact surface 86, the area of ​​the cap surface 84, and / or other characteristics of the braking system 40. Figure 2 When the piston cap 82 is compressed against the pressure plate 70, the deformation causes the cap surface 84 to reduce the curvature of the convex surface of the contact surface 86, allowing the piston cap 82 to distribute the force transmitted to the pressure plate 70 more evenly across the entire cap surface 84. In the example, the piston cap 82 is configured to deform (e.g., elastically deform) such that when the piston body 80 compresses the cap surface 84 against the contact surface 86, the contact pressure on the contact surface 86 remains below a threshold contact pressure. The threshold contact pressure may be based on, for example, the brittle fracture characteristics of a portion of the pressure plate 70 (e.g., an antioxidant coating, such as layer 96), the ultimate stress concentration within the pressure plate 70, or some other parameter.

[0041] Piston cap 82 is configured such that when cap surface 84 is compressed against contact surface 86, the curvature of the convexity on cap surface 84 decreases. In the example, when cap surface 84 is compressed against contact surface 86 with a compressive force sufficient to compress the pressure plate 70 against the stacked discs 58, the curvature of cap surface 84 decreases. Figure 2 In the example, the piston cap 82 is configured such that the convexity becomes substantially flattened when the cap surface 84 is compressed against the contact surface 86. The piston body 80 may be configured to translate such that the cap surface 84 is compressed against the contact surface 86. For example, Figure 4 The diagram shows the piston body 80 translated by a displacement ΔD to cause compression of the cap 84 against the contact surface 86. The piston body 80 can be configured to apply a compressive force F to the piston cap 82 to cause compression of the cap 84 against the contact surface 86. Figure 4 In one example, the piston body 80 applies a compressive force F to the piston cap 82 by means of a piston wall 88 surrounding a rear perimeter 94 defined by a rear surface 85 and at least partially surrounding the piston axis P; however, in other examples, the piston body 80 may apply the compressive force F to other locations on the piston cap 82.

[0042] The piston cap 82 can be configured to deform (e.g., elastically deform) in response to a compressive force F exerted by the contact surface 86 on the cap surface 84. The piston cap 82 can deform such that the cap surface 84 ( Figure 3The convexity of the piston cap 82 is reduced, its curvature is reduced, and / or it becomes substantially flattened. The piston cap 82 is deformable such that the cap surface 84 engages (e.g., contacts) the contact surface 86 substantially above the section of the cap surface 84 from the piston axis P to the periphery 89 defined by the cap surface 84. In the example, a portion of the piston cap 82 (e.g., a portion defining the convexity) may be configured to deflect toward the contact surface 86 when the cap surface 84 is compressed against the contact surface 86. The periphery 89 may at least partially surround the piston axis P. In the example, the periphery 89 is the outer boundary of the cap surface 84, which is configured to contact the pressure plate 70 when the cap surface 84 is compressed against the pressure plate 70.

[0043] The piston cap 82 is configured to transmit the compressive force F from the piston body 80 to the contact surface 86 and the pressure plate 70. The piston cap 82 may be configured to transmit the compressive force F such that the pressure plate 70 translates and the compression discs stack 58. Figure 2 For example, piston cap 82 may be configured to transmit compressive force F to induce a force distribution denoted by FP on contact surface 86 and pressure plate 70. The force distribution FP is merely representative and may have any general shape. In the example, piston cap 82 is configured to deform when cap surface 84 is compressed against contact surface 86 to produce a more uniform force distribution FP than would be possible without deformation of piston cap 82. Piston cap 82 may be configured such that the convexity of cap surface 84 becomes substantially flattened when cap surface 84 is compressed, allowing piston cap 82 to distribute the compressive force F more uniformly across cap surface 84. A more uniform force distribution FP can reduce stress concentration generated within pressure plate 70 during compression, thereby reducing wear and / or damage to pressure plate 70 that may occur during repeated application of compressive force F (e.g., during repeated braking operations). In some examples, contact surface 86 is defined by a layer 96 (such as an antioxidant coating or other layer) on the plate body 97 of pressure plate 70. A more uniform force distribution FP can reduce wear and / or damage to layer 96. For example, a more uniform force distribution can reduce and / or substantially eliminate brittle fracture of layer 96.

[0044] Figure 5A and Figure 5B A schematic diagram of piston 76 is provided. Figure 5A The piston body 80 and piston cap 82 are shown as cross sections, with the cutting plane and piston axis P parallel to the page. Figure 5B The piston axis P is shown perpendicular to the cover surface 84 of the page. The piston cover 82 can be configured such that the cover surface 84 defines an inner surface segment 98, an intermediate surface segment 102, and an outer surface segment 104. In some examples, as shown in Figure 5, both the intermediate surface segment 102 and the outer surface segment 104 define convex surfaces. The inner surface segment 98 can define a surface substantially parallel to the contact surface 84. Figure 3 and Figure 4(e.g., substantially perpendicular to the piston axis P). In some examples, the inner surface segment 98 defines an inner convex surface. The inner convex surface may be adjacent to or separate from the convex surface defined by the intermediate surface segment 102. In other examples (e.g., Figure 6 In the contact surface 84, the inner surface section 98, the intermediate surface section 102, and / or the outer surface section 104 may define a convex surface, a concave surface, or a surface substantially parallel to the contact surface 84. For example, the intermediate surface section 102 may define a convex surface, while the outer surface section 104 may define a concave surface.

[0045] The inner surface section 98 may intersect and / or be closest to the piston axis P intersecting the cap surface 84. The outer surface section 104 may be adjacent to the perimeter 89 defined by the cap surface 84. The intermediate surface section 102 may be substantially between the inner surface section 98 and the outer surface section 104. In some examples, such as Figure 5B As shown, the inner surface segment 98 is a generally circular, elliptical, or oval region of the cover surface 84 that intersects with and / or is closest to the piston axis P intersecting the cover surface. The intermediate surface segment 102 may substantially surround the inner surface segment 98 and / or be located near it. In the example, the intermediate surface segment 102 defines a first ring (e.g., a first toroidal surface) surrounding the inner surface segment 98. The outer surface segment 104 may substantially surround the intermediate surface segment 102 and / or be located near it. In the example, the outer surface segment 104 substantially surrounds the intermediate surface segment 102 and the inner surface segment 98. In the example, the outer surface segment 104 defines a second ring (e.g., a second toroidal surface) surrounding the intermediate surface segment 102 and the inner surface segment 98.

[0046] Piston cap 82 may be configured such that when piston cap 82 is in a relaxed state (e.g., in the absence of compressive force F), Figure 3 , Figure 4 In the case of ( ), the intermediate surface section 102 defines a convexity on the cover surface 84. The piston cover 82 may be configured such that when the piston cover 82 is in a relaxed state, the intermediate surface section 102 is substantially curved away from the pressure plate 70. In the example, the piston cover 82 is configured to deform when the cover surface 84 is compressed against the pressure plate 70, such that the intermediate surface section 102 is substantially deflected to contact the pressure plate 70 during compression.

[0047] In the example, piston cap 82 is configured such that when piston cap 82 is in a substantially relaxed state and piston 76 is configured to apply force to translate pressure plate 70 ( Figure 3 , Figure 4In the example, the inner surface section 98 is substantially parallel to the contact surface 86. In other examples, the inner surface section 98 may define a convexity or some other curvature. The cap 84 may be configured such that when the cap 84 is compressed against the pressure plate 70, the inner surface section 98 encounters the contact surface 86, and the intermediate surface section 102 deflects to encounter the contact surface 86. In the example, the piston cap 82 deforms such that the intermediate surface section 102 encounters the contact surface 86. The piston cap 82 may be configured such that deformation is reduced and / or substantially eliminated, buckling of the piston cap 82 under compressive force F. Reducing and / or substantially eliminating buckling of the cap 84 reduces the tendency of the piston cap 82 to deform, such that the cap 84 tends to transfer a significant portion (or most) of the compression F substantially above an annular region around the piston axis P, or through some other pattern that tends to create excessive stress concentration in the pressure plate 70.

[0048] In the example, piston body 80 and piston cap 82 may define a cavity 106 (e.g., volume) within piston 76. Piston cap 82 may be configured such that when a force is applied against cap surface 84, at least a portion of piston cap 82 deflects (e.g., deforms) inward toward cavity 106. For example, piston cap 82 may be configured such that when a force is applied to cap surface 84 toward cavity 106, a portion of piston cap 82 including an inner surface segment 98 deflects inward toward cavity 106. Piston 76 may be configured such that when piston cap 82 is in contact with pressure plate 70 (… Figure 4 When a force distribution FP is generated on the piston 76 and the pressure plate 70 applies equal and opposite reaction forces to the cover surface 84, the cover surface 84 and / or the back surface 85 deflect inward toward the cavity 106. In the example, the piston 76 is configured such that the piston inner surface 90 and the back surface 85 substantially define the piston cavity 106. The piston cap 82 may be configured such that the back surface 85 is substantially between the piston cavity 106 and the cover surface 84.

[0049] The piston cap 82 may be configured such that a portion of the piston cap 82 deflects toward the cavity 106 as the convex surface defined by the cap surface 84 is compressed against the contact surface 86 and becomes substantially flattened (e.g., its curvature is reduced). This deflection of the piston cap 82 toward the cavity 106 can result in a more uniform distribution of the compressive force F across the entire cap surface 84 as the piston cap 82 transmits the compressive force F to the pressure plate 70. In the example, as the cap surface 84 is compressed against the contact surface 86, a portion of the inner surface segment 98 deflects toward the cavity 106 as a portion of the intermediate surface segment 102 deflects toward the contact surface 86.

[0050] In the example, the piston cap 82 is configured such that local stiffness (e.g., stiffness on a section of the piston cap 82) varies across the piston cap 82. Local stiffness may depend on one or more material properties of the material constituting the piston cap 82, such as Young's modulus, Poisson's ratio, or other material properties. Local stiffness may depend on one or more dimensional properties of the piston cap 82, such as the thickness of the piston cap 82, the distance of the section from the piston axis P, or other dimensional properties. In some examples, the piston cap 82 is configured to produce one or more equivalent stiffness values ​​when the piston cap 82 is compressed against the contact surface 86. Equivalent stiffness may be based on one or more material properties and dimensions of the piston cap 82 and one or more material properties and dimensions of the pressure plate 70. Equivalent stiffness may be based on the deformation of the piston cap 82 when the cap surface 84 is compressed against the pressure plate 70. In the example, the piston cap 82 is configured such that the equivalent stiffness between the piston cap 82 and the pressure plate 70 causes a relatively uniform force distribution FP from the piston cap 82 to the pressure plate 70. In the example, the piston cap 82 is configured such that the equivalent stiffness causes the contact pressure between the piston cap 82 and the pressure plate 70 to remain below a threshold. In the example, when the piston cap 82 is in a relaxed state (e.g., displaced from the contact surface 86), the curvature of the piston cap 82 is based on the desired compatibility stiffness when the piston cap 82 is compressed against the pressure plate 70.

[0051] The piston cap 82 can be configured to define a thickness between a cap surface 84 and a back surface 85. The thickness can be determined, for example, in a direction substantially parallel to the piston axis P. The piston cap 82 can be configured such that the thickness varies based on a distance from the piston axis P (e.g., a distance substantially perpendicular to the piston axis P). The piston cap 82 can be configured such that at some portion of the piston cap 82, the thickness increases with increasing distance from the piston axis P. For example, the piston cap 82 can be configured to define a first thickness t1 at a first distance d1 from the piston axis P and a second thickness t2 at a second distance d2 from the piston axis P, wherein the first thickness t1 is less than the second thickness t2 and the first distance d1 is less than the second distance d2. The piston cap 82 can be configured such that when the piston cap 82 is deformed by compression against the pressure plate 70, the change in thickness helps to distribute the compressive force F to the pressure plate 70.

[0052] The piston cap 82 may be configured to define a concave surface over a portion of the cap surface 84 when the piston cap 82 is in a relaxed state (e.g., when the piston cap 82 is compressed without abutting the pressure plate 70). In an example, the piston cap 82 may be configured to define a concave surface over a portion of the outer surface segment 104. In an example, the concave surface defines a second curvature. In an example, the piston cap 82 is configured such that when the cap surface 84 is compressed against the contact surface 86, the concavity defined by the concave surface reduces its curvature. In an example, the second curvature of the concave surface (or a portion of the concave surface) has an inverse relationship with a second radius of curvature, where the second radius of curvature is the radius of the circle that best fits the curvature defined by the concave surface. The concave surface may be configured such that when the concave surface reduces the second curvature, the second radius of curvature increases.

[0053] In the example, the piston cap 82 defines a concave surface over a portion of the outer surface section 104. In the example, the piston body 80 is configured to apply a compressive force F against a rear periphery 94, and the concavity is opposite to that of the rear periphery 94, such that a line parallel to the piston axis P intersects both the rear periphery 94 and the concave surface defined on the cap surface 84. In some examples, the piston cap 82 defines a concave surface over a portion of the outer surface section 104 and a convex surface over a portion of the intermediate surface 102.

[0054] Figure 6 A portion of a piston cap 82 in a relaxed state is shown, wherein the piston cap 82 defines a concave surface on a cap surface 84. The cap surface 84 includes an inner surface segment 98, an intermediate surface segment 102, and an outer surface segment 104. Figure 6 The piston cap 82 is shown as a cross-section, with the cutting plane parallel to the page. Figure 6 In one example, outer surface segment 104 defines a concave surface exhibiting concavity (e.g., negative curvature) relative to vector v2. Intermediate surface segment 102 defines a convex surface exhibiting convexity (e.g., positive curvature) relative to vector v3. In some examples, inner surface segment 98 defines a substantially flat, uncurved surface, such that a portion of inner surface segment 98 defines a surface that exhibits substantially no curvature relative to vector v4. In other examples, inner surface segment 98 may be configured to define positive or negative curvature relative to vector v4. Vectors v2, v3, and v4 are perpendicular to outer surface segment 104, intermediate surface segment 102, and inner surface segment 98, respectively, and have directions away from outer surface segment 104, intermediate surface segment 102, and inner surface segment 98.

[0055] In the example, plane P3 perpendicular to vector v2 and plane P2 perpendicular to piston axis P define an angle θ2 between P3 and P2, and the concave surface of cover 84 is defined such that angle θ2 decreases in the direction from vector v2 to the perimeter 89 defined by cover 84. Piston 82 may be configured such that angle θ2 decreases (e.g., decreases to substantially zero degrees) when cover 84 is compressed against contact surface 70. In the example, a “substantially flat” surface may mean a surface in which a plane perpendicular to piston axis P and a plane parallel to the surface define an angle of less than one degree between the planes, less than 0.5 degrees in some examples. In some examples, a “substantially flat” surface has an axial variation that is typically less than 0.01 inches, less than 0.005 inches in some examples.

[0056] Piston cap 82 is configured to receive compressive force (e.g., compressive force F) at a contact area defined by back surface 85 (such as back surface periphery 94). Figure 4 The piston cap 82 may define a concave surface on the cap surface 84 at a location substantially opposite the contact area. In the example, a line parallel to the piston axis P intersects both the contact area and the concave surface defined on the cap surface 84. For example, in Figure 6 In this configuration, the cover surface 84 may be configured to receive from the piston body (e.g., piston body 80) on a contact area defined substantially by the rear periphery 94 of the rear surface 85. Figure 3 , Figure 4 , Figure 5A , Figure 5B The compressive force. A line L1 parallel to the piston axis P intersects both the back periphery 94 and the concave surface defined by the cover surface 84 above a portion of the outer surface section 104. The piston cover 82 is configured such that when a compressive force is applied against the back periphery 94 and the cover surface 84 is compressed against the pressure plate 70, ( Figure 2 , Figure 3 , Figure 4 The concave surface defined by the cover 84 is substantially flattened (e.g., its curvature is reduced). The piston cover 82 may be configured such that the flattening of the concavity when the cover 84 is compressed against the pressure plate 70 contributes to the distribution of compressive force across the entire cover 84, resulting in a more distributed force distribution FP within the pressure plate 70.

[0057] Depend on Figure 3 , Figure 4 , Figure 5A , Figure 5B and Figure 6The depicted piston cap 82 may have a cross-section of a body of revolution. In the example, a portion or substantially all of the cap surface 84 and / or the back surface 85 defines a planar curve within a plane including the piston axis P, and the shape of the piston cap 82 is substantially defined by the planar curve rotating fully or partially around the piston axis P. The piston cap 82 may have other shapes and is defined by other methods in other examples.

[0058] The cover 84, back 85, piston body 80, and / or other portions of piston 76 may have any suitable orientation relative to the piston axis P. Piston body 80 may engage piston cap 82 in any suitable manner and with any fit sufficient to apply compressive force to piston cap 82. In the example, piston body 80 mechanically engages piston cap 82 using welding, solder, fasteners and adhesives, threads, engineered fits such as sliding fits, position fits, transition fits or interference fits, or some other mechanical engagement.

[0059] The piston cover 82, piston body 80, pressure plate 70, brake system 40, wheel 10, and their components can be formed to have any shape. In some examples, two or more components of the piston cover 82, piston body 80, pressure plate 70, brake system 40, and / or wheel 10 are formed to be physically separate from each other and subsequently joined and / or attached to the piston cover 82, piston body 80, pressure plate 70, brake system 40, and / or wheel 10. In other examples, two or more components of the piston cover 82, piston body 80, pressure plate 70, brake system 40, and / or wheel 10 have an integral body construction, for example, formed as a single piece.

[0060] The piston cap 82, piston body 80, pressure plate 70, brake system 40, wheel 10, and their components may be made of any suitable material. For example, the material may be any material that has suitable strength for the intended use of the piston cap 82, piston body 80, pressure plate 70, brake system 40, wheel 10, and their components. In some examples, the material includes metals or metal alloys. The piston cap 82, piston body 80, pressure plate 70, brake system 40, wheel 10, and their components may be formed using any suitable technique. The piston cap 82, piston body 80, pressure plate 70, brake system 40, wheel 10, and their components may be forged from bar stock, cast, manufactured, produced by additive manufacturing (e.g., three-dimensional (3D) printing), extruded, drawn, or produced using other suitable methods. In some examples, the piston cap 82, piston body 80, pressure plate 70, brake system 40, wheel 10, and their components may be machined to define the configuration described herein. In other examples, the piston cover 82, piston body 80, pressure plate 70, brake system 40, wheel 10 and its components may be formed without the need for basic machining.

[0061] Wheel 10 may be finished from near-net-shaped forged aluminum and includes axial components and / or wheel rims for assembling brake system 40 onto wheel 10. In other examples, wheel 10 may be manufactured in a different manner. In still other examples, wheel 10 may be obtained instead of manufactured. Wheel 10 may be made of any suitable material. In some examples, wheel 10 comprises metal or metal alloy. For example, wheel 10 may comprise aluminum, nickel alloy, steel alloy (e.g., stainless steel), titanium, carbon composite, or magnesium.

[0062] The brake discs described herein (including rotor discs 60, 61, 62, 63 and stator discs 64, 65, 66) can be made of any suitable material. In some examples, the brake discs described herein can be made of metal or metal alloys (such as steel alloys). In some examples, the brake discs can be made of carbon-carbon composite materials. In some examples, the brake discs can be made of carbon-carbon composite materials with high thermal stability, high wear resistance, and / or stable frictional properties. The brake discs may include carbon materials having multiple carbon fibers and dense material. The carbon fibers may be arranged as a single layer or multiple layers in woven or nonwoven fabrics.

[0063] Figure 7 A flowchart illustrating an exemplary technique for operating a braking system is shown. While this technique primarily refers to piston 76 and its components ( Figures 2 to 6 While described in this paper, the technique can be used with other pistons in other examples.

[0064] The technique includes translating piston 76 toward pressure plate 70 of brake system 40 (110). The technique may include translating piston 76 toward pressure plate 70 using actuator 74 of brake system 40. Brake system 40 may be located within wheel cavity 22 of wheel 10 and is configured to reduce and / or prevent rotation of wheel 10 about axis A. In an example, the technique includes translating piston cap 82 of piston 76 toward pressure plate 70 using translation of piston body 80 of piston 76. The technique may include translating piston 76 in a direction substantially parallel to axis A.

[0065] The technique includes compressing the cover surface 84 of the piston cap 82 against the contact surface 86 of the pressure plate 70. The technique may include applying a compressive force F to the piston cap 82 using the piston body 80, causing the cover surface 84 to compress against the contact surface 86. The technique includes reducing the curvature (e.g., substantially flattening) of the convex surface defined by the cover surface 84 when it is compressed against the contact surface 86 (112). The convex surface may define a convexity having a positive curvature relative to vectors v1, v3 extending from the cover surface 84 in a direction perpendicular to the cover surface 84 and toward the contact surface 86. The technique may include elastically deforming the piston cap 82 when the cover surface 84 is compressed against the contact surface 86. In an example, the cover surface 84 intersects the piston axis P of the piston 76. The technique may include translating the piston 76 in a direction substantially parallel to the piston axis P. The technique may include generating a force distribution FP within the pressure plate 70 when the cover surface 84 is compressed against the contact surface 86.

[0066] The cap 84 may define an inner surface segment 98 intersecting the piston axis P, an outer surface segment 104 adjacent to a periphery 89 of the cap 84, and an intermediate surface segment 102 between the inner surface segment 98 and the outer surface segment 104. The intermediate surface segment 102 may define a convex surface. In an example, the technique includes bringing the intermediate surface segment 102 into contact with the contact surface 86 when the cap 84 is compressed against the contact surface 86. The technique may include elastically deforming the piston cap 82 such that the intermediate surface segment 102 deflects toward the contact surface 86.

[0067] The technique includes compressing the disc stack 58 (114) when the cover 84 is compressed against the contact surface 86. The technique may include translating the pressure plate 70 using the compression of the cover 84 against the contact surface 86. The pressure plate 70 may be configured to cause compression of the disc stack 58 upon translation of the pressure plate 70. In the example, the braking system 40 is configured to cause the pressure plate 70 to apply a reaction force against the cover 84 when the cover 84 is compressed against the contact surface 86.

[0068] In this example, the technique includes deflecting a portion of the piston cap 82 toward a piston cavity 106 defined within the piston 76 when the cap 84 is compressed against the contact surface 86. The piston cavity 106 may be defined by a piston body 80 and a back surface 85 of the piston cap 82 opposite to the cap 84. In this example, the back surface 85 defines at least partially around a back periphery 94 of the piston axis P and / or the piston cavity 106, and the piston body 80 applies a compressive force F on the back periphery 94. In this example, the technique includes deflecting a portion of the piston cap 82 toward the piston cavity 106, wherein this portion of the piston cap 82 is configured to define an increasing thickness between the cap 84 and the back surface 85 as the distance from the piston axis P increases.

[0069] This technique may include reducing the curvature of the concave surface defined by the cover surface 84 when it is compressed against the contact surface 86. The concave surface may define a concavity that has a negative curvature relative to a vector v2 extending from the cover surface 84 in a direction perpendicular to the cover surface 84 and toward the contact surface 86. In the example, the outer surface segment 104 defines the concave surface. This technique may include elastically deforming the piston cap 82 when the cover surface 84 is compressed against the contact surface 86, such that the concave surface reduces its curvature. This technique may include reducing the curvature of the concave surface when the cover surface 84 is compressed against the contact surface 86.

[0070] This disclosure includes the following embodiments.

[0071] Example 1: A braking system comprising: a pressure plate defining a contact surface, wherein the pressure plate is configured to compress a disc stack of the braking system; and a piston configured to cause the pressure plate to compress the disc stack, the piston comprising: a piston body configured to translate along a piston axis; and a piston cap defining a cap surface intersecting the piston axis and defining a periphery around the piston axis, wherein the cap surface defines an inner surface segment intersecting the piston axis, an outer surface segment adjacent to the periphery, and an intermediate surface segment between the inner surface segment and the outer surface segment, wherein the intermediate surface segment defines a convex surface defining a curvature, wherein the piston body is configured to abut against the contact surface of the pressure plate to compress the cap surface to cause the pressure plate to compress the disc stack, and wherein the convex surface is configured to reduce the curvature when the piston body abuts against the contact surface to compress the cap surface.

[0072] Example 2: The braking system according to Example 1, wherein the inner surface section is configured to be substantially parallel to the contact surface when the cover is displaced from the contact surface.

[0073] Example 3: The braking system according to Example 1 or 2, wherein the piston cover is configured to be elastically deformable such that when the piston body abuts against the contact surface to compress the cover, the inner surface section and the intermediate surface section contact the contact surface.

[0074] Example 4: A braking system according to any one of Examples 1 to 3, wherein the cover defines a concave surface that defines a second curvature, wherein the concave surface is configured to reduce the second curvature when the piston body abuts against the contact surface and compresses the cover.

[0075] Example 5: The braking system according to Example 4, wherein the outer surface section defines a concave surface.

[0076] Example 6: A braking system according to any one of Examples 1 to 5, wherein the piston cap defines a back side opposite to the cover surface, wherein the piston cap defines a thickness from the cover surface to the back side that is substantially parallel to the piston axis, and wherein the thickness increases with the distance from the piston axis toward the periphery.

[0077] Example 7: A braking system according to any one of Examples 1 to 6, wherein the piston cover defines a rear side opposite to the cover surface, wherein the rear side defines a rear periphery around the piston axis, and wherein the piston body is configured to apply a force on the rear periphery such that the piston body abuts against the contact surface to compress the cover surface.

[0078] Example 8: A braking system according to any one of Examples 1 to 7, wherein the pressure plate comprises a plate body layered by a coating, wherein the coating defines a contact surface, and wherein the coating is more brittle than the plate body.

[0079] Example 9: A braking system according to any one of Examples 1 to 8, wherein: a piston cover defines a back surface opposite to the cover surface; a piston body defines a piston wall having an inner surface facing the piston axis and an outer surface opposite to the inner surface; the inner surface and the back surface define a piston cavity intersecting the piston axis; and the piston wall is configured to apply force on the back surface to compress the cover surface against the contact surface of the piston body.

[0080] Example 10: A braking system according to any one of Examples 1 to 9, wherein a piston body and a piston cover define a cavity within the piston, wherein the piston cover is located between a contact surface and the cavity, and wherein the piston cover is configured to deflect toward the cavity when the piston body abuts against the contact surface and compresses the cover surface.

[0081] Example 11: A braking system according to any one of Examples 1 to 10, wherein the braking system is configured such that when the piston body abuts against the contact surface to compress the cover surface, the pressure plate applies a reaction force on the cover surface.

[0082] Example 12: A braking system according to any one of Examples 1 to 11, wherein the pressure plate comprises a carbon composite material.

[0083] Example 13: The brake system according to any one of Examples 1 to 12 further includes a disc stack, wherein the disc stack includes at least one rotor disc and at least one stator disc, wherein the brake system is configured such that when the piston body abuts against the contact surface compression cover, the friction surface on the rotor disc contacts the friction surface on the stator disc.

[0084] Example 14: A brake system according to any one of Examples 1 to 13, wherein the disc stack includes a stator disc and a rotor disc, the stator disc being configured to remain stationary relative to the torque tube of the brake system, and the rotor disc being configured to rotate relative to the torque tube of the brake system.

[0085] Example 15: A braking system comprising: a pressure plate defining a contact surface, wherein the pressure plate is configured to compress a disc stack of the braking system; and a piston defining a piston axis and configured to cause the pressure plate to compress the disc stack, the piston comprising: a piston cap defining a cap face intersecting the piston axis and a back face opposite the cap face, wherein the cap face defines a periphery surrounding the piston axis, and the back face defines a rear periphery surrounding the piston axis, wherein the cap face defines an inner surface segment intersecting the piston axis, an outer surface segment adjacent to the periphery, and a rear surface segment within the inner periphery. An intermediate surface segment between a surface segment and an outer surface segment, wherein the intermediate surface segment defines a convex surface that defines curvature; and a piston body configured to translate along a piston axis, wherein the piston body and a rear side define a piston cavity intersecting the piston axis, wherein the piston body is configured to apply force on its rear periphery to abut against a contact surface of a pressure plate to compress the cover, wherein the piston cover is configured such that when the piston body abuts against the contact surface to compress the cover, a concave surface reduces curvature, and wherein abutting against the contact surface to compress the cover causes the pressure plate to stack.

[0086] Example 16: The brake system according to Example 15, wherein the piston body and piston cover define a cavity within the piston, wherein the piston cover is located between the contact surface and the cavity, and wherein the piston cover is configured to deflect toward the cavity when the piston body abuts against the contact surface and compresses the cover surface.

[0087] Example 17: The braking system according to Example 15 or 16, wherein the inner surface section is configured to be substantially parallel to the contact surface when the cover is displaced from the contact surface.

[0088] Example 18: A braking system according to any one of Examples 15 to 17, wherein the outer surface section defines a concave surface.

[0089] Example 19: A method comprising: translating a piston body of a piston toward a contact surface of a pressure plate along a piston axis defined by a piston; translating a piston cap having a cover toward the contact surface using the translation of the piston body, the cover defining an inner surface segment intersecting the piston axis, an outer surface segment adjacent to the periphery of the cover, and an intermediate surface segment between the inner surface segment and the outer surface segment, wherein the intermediate surface segment defines a convex surface defining a curvature; reducing the curvature of the convex surface by compressing the cover against the contact surface using the piston body; and compressing the stacked discs using the pressure plate while the cover is compressed against the contact surface.

[0090] Example 20: According to the embodiment of claim 19, it further includes applying a force using the piston body on the rear periphery of the piston cap on the back side opposite to the cap surface, the rear periphery being about the piston axis.

[0091] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

1. A braking system, the braking system comprising: A pressure plate that defines a contact surface, wherein the pressure plate is configured to compress the disc stack of the braking system; and A piston configured to cause the pressure plate to compress the stack of discs, the piston comprising: A piston body configured to translate along a piston axis; as well as A piston cap, the piston cap defining a cap surface intersecting the piston axis and defining a periphery surrounding the piston axis. The cover defines an inner surface segment intersecting the piston axis, an outer surface segment adjacent to the periphery, and an intermediate surface segment between the inner surface segment and the outer surface segment. The intermediate surface segment defines a convex surface, and the convex surface defines a curvature. The piston body is configured to press against the contact surface of the pressure plate to compress the cover surface, thereby causing the pressure plate to compress the stack of discs. The convex surface is configured to reduce the curvature when the piston body abuts against the contact surface and compresses the cover surface. The piston cap defines a back surface opposite to the cap surface and defines a thickness from the cap surface to the back surface that is substantially parallel to the piston axis. In at least a portion of the piston cap, the thickness increases with the distance from the piston axis toward the periphery.

2. The braking system of claim 1, wherein the inner surface section is configured to be substantially parallel to the contact surface when the cover is displaced from the contact surface.

3. The braking system according to claim 1 or claim 2, wherein the piston cover is configured to elastically deform such that when the piston body abuts against the contact surface to compress the cover, the inner surface section and the intermediate surface section contact the contact surface.

4. The braking system of claim 1 or claim 2, wherein the cover defines a concave surface, the concave surface defines a second curvature, wherein the concave surface is configured to reduce the second curvature when the piston body compresses the cover against the contact surface.

5. The braking system of claim 4, wherein the outer surface section defines the concave surface.

6. The braking system of claim 1 or claim 2, wherein the back side defines a rear periphery around the piston axis, and wherein the piston body is configured to apply a force on the rear periphery such that the piston body abuts against the contact surface to compress the cover.

7. The braking system according to claim 1 or claim 2, wherein the braking system is configured such that when the piston body abuts against the contact surface to compress the cover surface, a pressure plate applies a reaction force on the cover surface.

8. The braking system of claim 1 or claim 2, wherein the piston body and the piston cap define a cavity within the piston, wherein the piston cap is located between the contact surface and the cavity, and wherein the piston cap is configured to deflect toward the cavity when the piston body compresses the cap surface against the contact surface.

9. An actuation method for an actuator system, the method comprising: The piston body of the piston is translated toward the contact surface of the pressure plate along the piston axis defined by the piston; The piston cap, having a cover surface, is translated toward the contact surface by the translation of the piston body. The cover surface defines an inner surface segment intersecting the piston axis, an outer surface segment adjacent to the periphery of the cover surface, and an intermediate surface segment between the inner surface segment and the outer surface segment. The intermediate surface segment defines a convex surface that defines a curvature. The piston cap defines a back surface opposite the cover surface. The piston cap defines a thickness from the cover surface to the back surface that is substantially parallel to the piston axis. The thickness increases with the distance from the piston axis toward the periphery of the cover surface. The curvature of the convex surface is reduced by compressing the cover surface against the contact surface using the piston body; as well as When the cover is compressed against the contact surface, the pressure plate is used to compress the stacked discs.

10. The actuation method of claim 9, further comprising applying a force on the rear periphery of the back side using the piston body, the rear periphery surrounding the piston axis.

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