Patent Application
20160304191
The present invention relates to aircraft braking systems. In particular, the invention relates to positioning of actuators relative to a center of an annular pressure disk.
Aircraft brake systems typically employ a series of friction disks forced into contact with each other to stop the aircraft. Friction disks splined to a non-rotating wheel axle are interspersed with friction disks splined to the rotating wheel. The friction disks withstand and dissipate the heat generated from contact between one another during braking. During high speed landings and rejected takeoffs (“RTOs”), the amount of heat generated can be significant.
A disk brake system, in accordance with various embodiments, includes a pressure plate having a center, an inner radius and an outer radius. The disk brake system also includes a first piston. The disk brake system also includes a first puck coupled to the first piston and configured to contact the pressure plate at a first distance from the center in response to the first piston being actuated. The first distance is different than an average of the inner radius and the outer radius.
A disk brake system, in accordance with various embodiments, includes a pressure plate having a center, an inner radius and an outer radius. The disk brake system also includes a first piston. The disk brake system also includes a first puck coupled to the first piston and configured to contact the pressure plate in response to the first piston being actuated. The first puck has a first dimension in a radial direction and a second dimension in a circumferential direction that is different than the first dimension.
The forgoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated herein otherwise. These features and elements as well as the operation of the disclosed embodiments will become more apparent in light of the following description and accompanying drawings.
The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present disclosures, however, may best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures, wherein like numerals denote like elements.
The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration and their best mode. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the inventions, it should be understood that other embodiments may be realized and that logical, chemical, and mechanical changes may be made without departing from the spirit and scope of the inventions. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact.
With reference to
Disk brake system 20 also includes a plurality of friction disks 38. The plurality of friction disks 38 includes at least one non-rotatable friction disk 40, also known as a stator, and at least one rotatable friction disk 42, also known as a rotor. Each friction disk 38 includes an attachment structure. In the embodiment of
Torque flange 22 is mounted to axle 12. Torque tube 24 is bolted to torque flange 22 such that reaction plate 34 is near an axial center of wheel 10. End plate 32 is connected to a surface of reaction plate 34 facing axially away from the axial center of wheel 10. Thus, end plate 32 is non-rotatable by virtue of its connection to torque tube 24. Stator splines 36 support pressure plate 30 so that pressure plate 30 is also non-rotatable. Stator splines 36 also support non-rotatable friction disks 40. Non-rotatable friction disks 40 engage stator splines 36 with gaps formed between stator lugs 44. Similarly, rotatable friction disks 42 engage rotor splines 18 with gaps formed between rotor lugs 46. Thus, rotatable friction disks 42 are rotatable by virtue of their engagement with rotor splines 18 of wheel 10.
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In some embodiments, pucks 52 may be coupled to reaction plate 34 and corresponding mating surfaces may be positioned on end plate 32 such that in response to actuation of pistons 26, a force is exerted on the rotatable friction disks 42 and the non-rotatable friction disks 40 towards reaction plate 34. In response to end plate 32 being within a predetermined distance of reaction plate 34, the pucks coupled to reaction plate 34 contact the corresponding mating surfaces such that during a rub event, end plate 32 and reaction plate 34 make contact via the pucks and the corresponding mating surfaces. Throughout the disclosure, shapes and positions of pucks 52 relative to pressure plate 30 are discussed. One skilled in the art will realize that the various shapes and positions of pucks 52 relative to pressure plate 30 can also be applied to the pucks and mating surfaces of reaction plate 34 and end plate 32. In various embodiments, the pucks of reaction plate 34 may be positioned at traditional locations relative to a center of reaction plate 34, in some embodiments, the pucks of reaction plate 34 may have the same shape and/or location relative to end plate 32 as pucks 52 have relative to pressure plate 30, and the pucks of reaction plate 34 may have different shapes and/or locations relative to end plate 32 as pucks 52 have relative to pressure plate 30.
With reference now to
A plurality of pucks 452, in accordance with various embodiments, including puck 452A, 452B and 452C may be positioned relative to pressure plate 30 as illustrated. In response to the actuators of the disk brake system being actuated, the plurality of pucks 452 contact pressure plate 30 at the illustrated locations and apply an axial force on pressure plate 30.
Studies have validated the fact that the greatest transfer of heat in a disk brake is axially aligned with the center of a puck due to pressure distribution resulting from actuation of the pistons. Stated differently, the heat is not evenly distributed across the radial dimension of the disk. The studies have also shown that properties of a carbon disk can change in the areas of greater heat due to a phenomena called a “hot band” that corresponds to rejected takeoff (RTO) fade.
Traditional disk brakes are designed such that the actuators contact the pressure plate at a radius determined using a predetermined formula. The radius at which the actuators are positioned may further vary slightly based on volumetric constraints of the system but is traditionally within five percent (5%) of the arithmetic average radius of the pressure plate. Traditional disk brakes are subject to heat buildup and RTO fade due to the speed at which heat is dissipated in traditional disk brakes. Plurality of pucks 452, however, are positioned such that they may or may not contact pressure plate 430 at an arithmetic average radius and are instead designed to be positioned at locations which will decrease the heat buildup and formation of “hot bands.”
A line 402 illustrates the average distance from each of the plurality of pucks 452 to center 301 (i.e., “puck average”). When referenced herein, a distance from a puck to center 301 corresponds to a distance from a center of the puck to center 301 and average distance refers to an arithmetic mean of inner radius 212 and outer radius 214. Each of the plurality of pucks 452 may be positioned at a distance 400 from a center 301 of pressure plate 30. In various embodiments and as illustrated in
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In
The staggering of pucks 554 and pucks 552 about pressure plate 30 distributes the friction areas of pressure plate 30 over a larger area of pressure plate 30. This distribution of friction areas may provide for faster dissipation of heat energy and less localized heat.
Pucks 554 and pucks 552 may have an average distance 508 (i.e., “puck average,” illustrated by a line 502) from center 301 that is greater than the average of inner radius 212 and outer radius 214. This provides more area for friction heat to dissipate. Additionally, as discussed above, the torque of a disk brake system may be related to the radius of the pucks from center 301. Accordingly, the torque of the disk brake system may be increased in response to average distance 508 being greater than the average of inner radius 212 and outer radius 214.
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Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the inventions. The scope of the inventions is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Different cross-hatching is used throughout the figures to denote different parts but not necessarily to denote the same or different materials.
Systems, methods and apparatus are provided herein. In the detailed description herein, references to “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments.
Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
