Abstract:
An aircraft brake assembly ( 10 ) includes a torque tube ( 16 ) having a passageway ( 18 ) for receiving a temperature probe, the passageway ( 18 ) having a wall and a width (W) and a length, and a temperature probe ( 20 ) having a width (w) less than the passageway width (W) and at least one angled portion ( 34, 36 ) where a centerline ( 44 ) of the temperature probe ( 20 ) changes direction. The temperature probe ( 20 ) has a lateral offset (L) greater than the passageway width (W) so that the probe ( 20 ) cannot be inserted into the passageway ( 18 ) without flexing it at the at least one angled portion ( 34, 36 ), and the temperature probe ( 20 ) is mounted in the passageway ( 18 ) and held in a flexed state by the passageway wall. Also a method of mounting a temperature probe in a brake assembly.

Description:
FIELD OF THE INVENTION 
     The present invention is directed toward an aircraft brake assembly having a temperature probe mounted in a passageway in a torque tube and toward a method of mounting a temperature probe in a torque tube, and, more specifically, toward an aircraft brake assembly having a temperature probe with an angled portion that can be flexed to fit the temperature probe into a torque tube passageway and toward a method of mounting a temperature probe in a torque tube that includes a step of flexing the temperature probe. 
     BACKGROUND OF THE INVENTION 
     An example of a portion of a conventional aircraft brake is illustrated in  FIG. 4 . This aircraft brake includes a plurality of spaced, parallel, stator disks  220  mounted on a torque tube  204 . The torque tube  204  is connected to a housing which in turn is mounted to an aircraft (not illustrated). A plurality of parallel spaced rotor disks  206  connected to a wheel  208  project into the spaces between the stator disks  220  and rotate freely between the stator disks  220  when the aircraft wheel  208  rotates. A housing  210  mounted on the torque tube  204  supports one or more pistons  212 , which may be electrically or hydraulically actuated, and that can be controllably driven against an outermost stator disk  214  to force the rotor and stator disks  202 ,  206  together to create friction and slow or stop the rotation of the wheel  208 . An assembly of rotor and stator disks may be referred to as a “brake stack,” and driving pistons against a brake stack to perform a braking operation may be referred to as compressing the brake stack. 
     It is known to provide a passageway  216  in the torque tube  204  for receiving a temperature probe  218  so that a temperature near the disk stack can be measured. The diameter of the temperature probe is generally selected to be slightly smaller than the diameter of the passageway  216  to facilitate the insertion and removal of the temperature probe. These temperature probes are generally mounted to the piston housing using a flange  222  at an outer end thereof and extend in a cantilevered manner into the passageway. While the gap between the temperature probe and the passageway is small, enough clearance remains so that the temperature probe can move and vibrate and thus flex repeatedly along its length under normal operating conditions. It has been found that these repeated vibrations cause the temperature probe to fail due to high cycle fatigue. 
     An interference fit between the temperature probe and the passageway might address this vibration problem, but given the length and other characteristics of the temperature probe, it would be difficult or impossible to mount a temperature probe in this manner. This vibration problem has been addressed in the past by wrapping the temperature probe with a metal or alloy mesh, a short section of which is illustrated as element  200  in  FIG. 4 , before inserting the temperature probe into the passageway. While this mesh reduces vibration, the high temperatures and conditions under which the probe operates have damaged the mesh and made the temperature probe difficult to remove from the passageway. In some cases, galvanic corrosion between the mesh and the passageway has bound the temperature probe in the passageway so tightly that the torque tube and temperature probe are both damaged during the removal process. It would therefore be desirable to provide a temperature probe that does not suffer from vibration induced cycle fatigue and which can be removed from a torque tube without damage. 
     SUMMARY OF THE INVENTION 
     These problems and others are addressed by embodiments of the present invention, a first aspect of which comprises a method of mounting an elongate temperature probe in a passageway of an aircraft brake assembly that includes providing a torque tube having a passageway with a width and a length, and providing a temperature probe with a width less than the passageway width and a lateral offset greater than the passageway width. The temperature probe also includes at least one angled portion where a centerline thereof changes direction. The method further involves inserting the temperature probe into the passageway to reduce the lateral offset of the temperature probe by flexing the temperature probe at the at least one angled portion so that the passageway holds the temperature probe in the flexed position against a return force generated by the flexed probe. 
     Another feature of the present invention comprises an aircraft brake assembly that includes a torque tube having a passageway for receiving an elongate temperature probe which passageway has a wall and a first width. A temperature probe having a second width less than the first width is mounted in the passageway. The temperature probe has a first portion spaced from the wall and angled toward a first location on the wall, a second portion spaced from the wall and angled away from the first location and a third portion between the first portion and the second portion in contact with the wall. 
     A further aspect of the invention comprises an aircraft brake assembly that includes a torque tube having a passageway for receiving a temperature probe which passageway has a wall and a width and a length. A temperature probe having a width less than the passageway width and at least one angled portion where a centerline of the temperature probe changes direction is mounted in the passageway. The temperature probe has a lateral offset greater than the passageway width so that the probe cannot be inserted into the passageway without flexing the temperature probe at the at least one angled portion, and the temperature probe is mounted in the passageway and held in a flexed state by the passageway wall. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These aspects and features of the invention and others will be better understood after a reading of the following detailed description together with the following drawings wherein: 
         FIG. 1  is a side elevational view, partly in section, of a temperature probe according to an embodiment of the present invention mounted in a passageway in an aircraft brake assembly; 
         FIG. 2  is a side elevational view of the temperature probe of  FIG. 1  aligned with a passageway; 
         FIG. 3  is a side elevational view of the temperature probe of  FIG. 2  inserted into the passageway of  FIG. 2 ; and 
         FIG. 4  is a sectional side elevational view of a conventional temperature probe mounted in an aircraft brake assembly. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, wherein the showings are for purposes of illustrating embodiments of the invention only and not for the purpose of limiting same,  FIG. 1  illustrates a portion of an aircraft brake assembly designated generally by the numeral  10 . Brake assembly  10  is generally similar to the brake assembly illustrated in  FIG. 4 , and only the portion of the brake assembly in the vicinity of the improved temperature sensor of an embodiment of the present invention is illustrated in the Figures. Brake assembly  10  includes a piston housing  12  having a passage  14  connected to a torque tube  16  having a passageway  18 . Passageway  18  has a width W and is aligned with passage  14 . A temperature probe  20  is also provided and includes an outer or connector end  22  having a flange  24 , a bushing  26  extending from flange  24 , a tubular portion  28  extending from bushing  26 , and a temperature sensor  30  at the other end of the tubular portion  28  from bushing  26 . The interior of the tubular portion  28  is hollow, and one or more wires  32  run through the temperature probe  20  from the temperature sensor  30  through connector end  22 . 
       FIG. 2  illustrates temperature probe  20  generally aligned with, but not inserted into, passageway  18  of torque tube  16 . For clarity of illustration, piston housing  12  is not shown. Tubular portion  28  of the temperature probe  20  includes a first angled portion  34 , a second angled portion  36 , a first linear portion  38  between flange  24  and first angled portion  34 , a second linear portion  40  between first angled portion  34  and second angled portion  36 , and a third linear portion  42  between second angled  36  and temperature sensor  30 . A centerline  44  of temperature probe  20  is also illustrated which centerline changes direction at each of the first and second angled portions  34 ,  36 . Tubular portion  28  of the temperature probe  20  has a width w. 
     First and second angled portions  34 ,  36  give the temperature probe  20  a lateral offset L comprising the separation between parallel lines tangential to the first and second angled portions  34 ,  36 . Stated differently, if the temperature probe were wave shaped, the lateral offset would correspond to twice the wave&#39;s amplitude. The drawings are not to scale, and the angle of the first and second angled portions  34 ,  36  of the temperature probe and the difference between lateral offset L and passageway width W are exaggerated for illustration purposes. The temperature probe may be cast or otherwise formed to have first and second angled portions  34 ,  36 , but, more often, the tubular portion of the temperature probe will be formed in a linear shape and then bent in a well known manner to form the first and second angled portions  34 ,  36 . As used herein, the term “bent” refers to the shape of the temperature probe and not to the manner that the shape was created. In either case, the metal or metal alloy from which the tubular portion is formed will have sufficient resiliency so as to resist the compression of the lateral offset, generate a return force when compressed, and spring back to substantially the original shape once a force holding the lateral offset in compression is released. 
     The unflexed lateral offset L of temperature probe  20  is greater than the width W of passageway  18 . Therefore, in order to insert the temperature probe  20  into passageway  18 , the lateral offset L of the probe must be reduced to L′ by flexing or compressing the tubular portion  28  of the temperature probe  20  at the first and second angled portions  34 ,  36 . This may be accomplished, for example, by placing temperature sensor  30  into passageway  18  and applying axial pressure against connector end  22  to compress the lateral offset L to a lateral offset L′ as the temperature probe  20  is forced into the passageway  18 . It may also be beneficial to flex the portion of the temperature probe  20  at the entrance of passageway  18  to facilitate the insertion of the temperature probe  20  into the passageway  18 . 
     As illustrated in  FIG. 3 , after insertion, the lateral offset L′ of the temperature probe  20  will be substantially the same as the width W of passageway  18 . It will be appreciated that when torque tube  16  is mounted on a piston housing  12 , the temperature probe  20  will be inserted into passage  14  of the piston housing before reaching passageway  18  of the torque tube. When fully inserted, flange  24  of the temperature probe  20  is secured to the piston housing  12  to hold the temperature probe  20  in place axially. The first linear portion  38  of tubular portion  28  is spaced from the walls of the passageway  18  and angled toward a first location on the wall of the passageway  18 , second linear portion  40  of tubular portion  28  is spaced from the walls of the passageway  18  and angled toward the first location, and first angled portion  34  of tubular portion  28  is located between the first and second linear portions  38 ,  40  and contacts the wall of the passageway at the first location. Similarly, second linear portion  40  is also angled toward a second location on the wall of passageway  18 , third linear portion  42  of tubular portion  28  is angled toward the second location, and second angled portion  36  of tubular portion  28  is located between second linear portion  40  and third linear portion  42  and contacts the wall of the passageway at the second location. 
     Because of the resiliency of the material forming the temperature probe  20 , and specifically, the tubular portion  28  of the temperature probe  20 , the tubular portion  28  will exert a force against the wall of passageway  18  as it attempts to return to its uncompressed shape. This outward pressure maintains the first and second angled portions  34 ,  36  in contact with the passageway  18 . This contact, in turn, damps vibration and reduces or eliminates the high cycle fatigue that occurred in conventional temperature probes supported in a cantilevered manner. Moreover, the temperature probe of this embodiment can readily be removed from the brake assembly for maintenance of the brake assembly and/or inspection of the temperature probe and reinserted into the brake assembly without damage to either the temperature probe  20  or the brake assembly. If the angles of the first and second angled portions  34 ,  36  are changed when the temperature probe  20  is removed from the brake assembly, the tubular portion  28  of the temperature probe  20  can be reworked or re-bent to return the tubular portion to a shape having a larger lateral offset than the width W of passageway  18 . The new or reworked shape does not need to be identical to the original shape. 
     Temperature probe  20  is illustrated with first and second angled portions  34  and  36 . However, the number of angled portions can be less than or greater than two without exceeding the scope of the present invention. For example, if a single angled portion is provided, the temperature probe would be generally V shaped, and the temperature sensor  30  and a portion of bushing  26  would engage the walls of the passage or passageway. Likewise, especially in applications requiring probes having relatively long tubular portions, three or more angled portions could be used to provide support along the entire length of the temperature probe. 
     The present invention has been described herein in terms of presently preferred embodiments. However, obvious modifications and additions to these embodiments will become apparent to those skilled in the relevant arts upon a reading of the foregoing disclosure. It is intended that all such additions and modifications form a part of the present invention to the extent they fall within the scope of the several claims appended hereto.