GB2613412A

GB2613412A - Temperature sensing device for aircraft wheel brake

Info

Publication number: GB2613412A
Application number: GB2204705.4A
Authority: GB
Inventors: Pereira da Cunha Mauricio; J Lad Robert; White Ian; Brüggemann Kurt; Downing Richard; Consola Maud
Original assignee: Airbus Operations SAS; Airbus Operations Ltd
Current assignee: Airbus Operations SAS; Airbus Operations Ltd
Priority date: 2021-11-30
Filing date: 2022-03-31
Publication date: 2023-06-07
Also published as: GB202204705D0

Abstract

Manufacturing a temperature sensing device for sensing aircraft wheel brake temperature, the method comprising forming a sensor element slot 602 in a sensing device substrate 606; mounting the SAW sensor element in the sensor element slot; and providing the temperature sensing device comprising the sensing device substrate with the SAW sensor element mounted in the sensor element slot. Preferably a sensor antenna is produced on a surface 610 of the sensing device substrate and coupled to the SAW sensor element. The sensor slot element may be cut so as to ensure movement of the SAW sensor element due to vibration/physical shock is inhibited. Preferably the sensor element slot is cut using a laser cutting technique. A temperature sensing device, an aircraft wheel brake comprising the temperature sensing device and an aircraft comprising the aircraft wheel brake are also claimed.

Description

TEMPERATURE SENSING DEVICE FOR AIRCRAFT WHEEL BRAKE

TECHNICAL FIELD

[0001] The present invention relates to sensing aircraft wheel brake temperature. More specifically, the present invention relates to a temperature sensing device.

BACKGROUND

100021 When aircraft wheel brakes are applied to reduce the speed of an aircraft, the temperature of the aircraft wheel brakes rises. It can be advantageous to monitor the temperature of the aircraft wheel brakes to, for example, ensure that the brakes do not overheat. For example, temperature sensors such as thermocouples can be used to sense temperature

SUMMARY

100031 A first aspect of the present invention provides a method of manufacturing a temperature sensing device for sensing aircraft wheel brake temperature, the method comprising: forming a sensor element slot in a sensing device substrate; mounting the SAW sensor element in the sensor element slot; and providing the temperature sensing device comprising the sensing device substrate with the SAW sensor element mounted in the sensor element slot.

100041 Optionally, the method according to the first aspect comprises producing a sensor antenna on a surface of the sensing device substrate.

100051 Optionally, the method according to the first aspect comprises electrically coupling the sensor antenna to the SAW sensor element.

100061 Optionally, the sensor element slot is cut using a laser cutting technique.

100071 Optionally, the sensor element slot is cut so as to firmly hold the SAW sensor element such that movement of the SAW sensor element due to application of vibration and/or physical shock to the temperature sensing device is inhibited 100081 According to a second aspect of the present invention, there is provided a temperature sensing device for sensing aircraft wheel brake temperature, the temperature sensing device comprising: a surface acoustic wave, SAW, sensor element mounted in a sensor element slot in a sensing device substrate.

100091 Optionally, in the temperature sensing device according to the second aspect, the sensor element slot is cut so as to firmly hold the SAW sensor element such that movement of the SAW sensor element due to application of vibration and/or physical shock to the temperature sensing device is inhibited.

100101 Optionally, in the temperature sensing device according to the second aspect, the sensor element slot is cut using a laser cutting technique.

100111 Optionally, the temperature sensing device according to the second aspect comprises: a sensor antenna on a surface of the sensing device substrate.

100121 Optionally, in the temperature sensing device according to the second aspect, the sensor antenna is electrically coupled to the SAW sensor element.

100131 According to a third aspect of the present invention, there is provided an aircraft wheel brake comprising the temperature sensing device according to the second aspect 100141 Optionally, in the aircraft wheel brake according to the second aspect, the temperature sensing device is attached to a brake disc of the aircraft wheel brake.

100151 According to a fourth aspect of the present invention, there is provided an aircraft comprising the aircraft wheel brake according to the third aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [0017] Figure 1 is a simplified schematic view of an aircraft on which examples may be deployed; [0018] Figure 2 is a simplified schematic view of a brake and a wheel of an aircraft landing gear assembly according to an example; [0019] Figure 3 is a simplified schematic block diagram of a temperature sensing device according to a first example; [0020] Figure 4 is a simplified schematic plan view of a surface acoustic wave sensor element, according to an example; [0021] Figure 5 is a simplified schematic block diagram of a temperature sensing system according to an example; [0022] Figure 6 is a simplified schematic side-cross sectional view of a temperature sensing device according to a first example; [0023] Figure 7 is a flow diagram of a method of manufacturing a temperature sensing device, according to an example; and [0024] Figure 8 is a simplified schematic side cross-section view of a sensing device substrate, according to an example

DETAILED DESCRIPTION

100251 The following disclosure relates to a temperature sensing device for sensing aircraft wheel brake temperature.

100261 Figure 1 is a simplified schematic view of an aircraft 100. The aircraft 100 comprises a plurality of landing gear assemblies 102. The landing gear assemblies may include main and nose landing gears that are deployed or extended during take-off and landing. Each landing gear assembly 102 includes wheels 104. The aircraft 100 comprises a computing system 106, which, for example, comprises one or more processors and one or more computer readable storage media. The aircraft 100 may also comprise instruments 108, such as instruments or sensors for measuring characteristics or parameters related to the aircraft, and instruments or sensors for measuring environmental characteristics.

100271 Figure 2 is a simplified schematic view of an aircraft wheel brake 200 associated with the wheel 104 of the aircraft 100. The wheel brake 200 applies a braking force to inhibit the rotation of the wheel 104 when applied. Each of the wheels of the aircraft 100 may have a wheel brake 200 associated with it. In this example, the wheel brake 200 comprises a plurality of brake discs 202 including a pressure plate 204, a reaction plate 206, and a number of rotors 208 and stators 210. In this example, the brake discs 202 include a plurality of rotors and stators, and the wheel brake 200 is therefore a multiple disc brake. In other examples, the wheel brake 200 may not be a multiple-disc brake: there may be only one disc 208, for example, between a pressure plate 204 and a reaction plate 206. In some examples, the brake discs 202 may include up to 9 discs or I I discs, or any other number which is suitable for a wheel brake of an aircraft. The brake discs 202 may collectively be referred to as a heat pack. The components of the wheel brake 200 (hereafter, for brevity, the wheel brake 200 is referred to simply as the brake 200) such as the brake discs 202 may be housed in a wheel brake housing (not shown). As referred to herein, the term brake is used as if to include such a wheel brake housing.

100281 It will be understood that the type of wheel brake used in an aircraft landing gear depends on the characteristics of the aircraft in question, such as size, carrying capacity and the like The following may be applied to any wheel brakes suitable for use as aircraft wheel brakes which heat up when applied to reduce aircraft speed, as discussed in the following.

100291 When the aircraft 100 travels along the ground supported by the landing gear assembly 102, the rotors rotate with the wheel 104 (the rotors are keyed to the wheel 104), whereas the stators, the pressure plate 204 and the reaction plate 206 do not rotate with the wheel 104 (the stators, the pressure plate 204 and the reaction plate 206 are keyed to a torque tube 218 associated with the wheel 104 which does not rotate with the wheel 104). When braking is applied, the pressure plate 204 is urged towards the reaction plate 206 so that the brake discs 202 come into contact with one another (as shown in box 212 of Figure 2) and friction acts to inhibit the rotational motion of the rotors, thus generating a braking force. When the brake 200 is applied, some of the kinetic energy of the aircraft 100 is absorbed into the brake discs 202 as heat (by the action of friction) Accordingly, the brake 200 heats up when it is applied to cause the aircraft 100 to slow down.

100301 Any one or more of the rotors, stators, pressure plate 204 and the reaction plate 206 may be composed of Carbon-Carbon (CC) composites. A brake including brake discs composed of CC composites may be referred to as a carbon brake. For example, the brake discs 202 may be composed of a graphite matrix reinforced by carbon fibers.

[0031] Those skilled in the art will appreciate that the environment of the brake discs 202 may be harsh due to vibration and/or physical shock during application of braking for example. The environment of the brake discs 202 may be harsh due to high temperatures reached by the brake discs 202, for example 10032] In this example, the aircraft 100 comprises a braking system 214 which controls the operation of the brake 200. The braking system 214 causes the brake 200 to be applied in response to a braking request (for example when a pilot of the aircraft 100 presses a brake pedal) For example, the brake 200 may be hydraulically actuated in which case the braking system 214 includes a hydraulic system (not shown) operationally connected with the brake 200. In other examples, the brake 200 may be electrically actuated in which case the braking system 214 includes an electronic brake actuation system The braking system 214 may be controlled by the computing system 106.

100331 Figure 3 is a simplified schematic view of a temperature sensing device 300. The temperature sensing device 300 is for sensing aircraft wheel brake temperature (for example, the temperature of the brake 200). For example, the temperature sensing device 300 may be attached to a component of the brake in order to sense the temperature of that component of the brake 200. For example, the temperature sensing device 300 may be attached to one of the brake discs 202. In the example of Figure 2, the temperature sensing device 300 is attached to one of the stators. For example, the temperature sensing device 300 is attached to a first stator 210a, as schematically shown.

100341 The temperature sensing device 300 may be attached to the first stator 210a in a manner that can withstand the high temperatures expected to occur at the first stator 210a. For example, the temperature sensing device 300 may be attached to the first stator 21 Oa by means of a ceramic adhesive. Ceramic adhesive may be intended to withstand high temperatures, for example in excess of 1000°C. For example, the ceramic adhesive may be applied between the first stator 210a and the temperature sensing device 300 and cured such that the temperature sensing device 300 is bonded to the first stator 210a using cured ceramic adhesive material (for example, ceramic epoxy adhesive material). In some examples, the first stator 210a comprises a first formation (for example, one or more grooves). The first formation may be formed by cutting, grinding, drilling, or boring the first formation into the material of the first stator 210a. In such examples, a second formation may be formed from the ceramic adhesive to interlock with the first formation. For example, the ceramic adhesive with the second formation may be an attachment element for attaching the temperature sensing device 300 to the first stator 210a. For example, the second formation is complementary to the first formation. For example, the first formation is a groove formed in the first stator 210a and the second formation is a spike which fits into the groove to inhibit movement between the first stator 210a the attachment element along an axial direction and a circumferential direction of the first stator 210a In some examples, providing the attachment element as described comprises applying uncured ceramic adhesive material to the surface of the first formation to create the second formation 100351 It will be appreciated that the temperature sensing device 300 may be attached to a brake disc in a number of ways. Alternatively, or in addition to the use of ceramic adhesive, other fasteners such as ceramic bolts may be used to attach the temperature sensing device 300. For example, a ceramic bolt may be passed through a through hole in the temperature sensing device 300 and engage with a threaded hole in the first stator 210a. In some examples, an appropriately shaped clip (for example, a metal clip) may be used as an attachment element. For example, the clip may comprise through holes and may be attached to the first stator 210a using bolts. Those skilled in the art will appreciate the various ways of attaching components to withstand high temperatures.

100361 The temperature sensing device 300 comprises a surface acoustic wave (SAW) sensor element 302. In the example of Figure 3, the temperature sensing device also comprises a sensor antenna 304, which is electrically coupled to the SAW sensor element 302. The temperature sensing device 300 may be a passive device in that it does not require electrical power to operate. It will be understood that the SAW sensor element 302 works based on SAWs generated in the SAW sensor element 302. For example, the SAW sensor element 302 comprises a transducer which converts an input signal (for example, an electrical signal) into a surface acoustic wave that resonates in the SAW sensor element 302. The SAW sensor element 302 also, for example, comprises a transducer to convert the SAW into an output signal (for example, an output signal).

100371 It will be understood that the SAW sensor element 302 works based on SAWs generated in the SAW sensor element 302. For example, the SAW sensor element 302 comprises a transducer which converts an input signal (for example, an electrical signal) into a surface acoustic wave that resonates in the SAW sensor element 302. The SAW sensor element 302 also, for example, comprises a transducer to convert the SAW into an output signal (for example, an output signal). Physical properties (such as temperature, for example) of the SAW sensor element may be determined based on the output signal.

100381 The input signal may be referred to as an interrogation signal. That is because the interrogation signal causes the output signal based on which, for example, temperature can be determined. The interrogation signal therefore acts to query the SAW sensor element 302 to provide an output signal. The interrogation signal may be wirelessly received by the temperature sensing device 300. The output signal may be wirelessly transmitted by the temperature sensing device 300.

100391 The SAW sensor element 302 comprises one or more interdigital transducers (IDTs). The IDTs are for converting between a SAW and, for example, an electrical signal. The functioning of an IDT is described further below. In some examples, the SAW sensor element 302 is a one-port SAW sensor. In such examples, the SAW sensor element 302 has one IDT. For example, the SAW sensor element 302 may have one IDT and reflectors either side of the IDT to reflect the SAW. In such examples, the one IDT converts an input signal into a SAW and also converts the SAW back into an electrical signal as a response (output) signal.

100401 In some examples, the SAW sensor element 302 is a two-port SAW sensor. In such examples, the SAW sensor element 302 comprises two IDTs spaced apart from one another. There is an input IDT which converts an input signal into a SAW. The SAW travels from the input IDT to an output IDT. The output IDT converts the SAW into an output signal. Those skilled in the art will appreciate the various configurations of a SAW sensor element.

100411 Figure 4 illustrates a particular example of the SAW sensor element 302. In this example, the SAW sensor element 302 is a two-port SAW sensor, and comprises an input IDT 402 and an output IDT 404. Each of the input IDT 420 and the output IDT 404 comprises two interlocking comb-shaped arrays of electrodes, deposited on the surface of a piezoelectric substrate 406 to form a periodic structure. The electrodes may be metallic electrodes, for example. In this example, the input MT 402 comprises a first periodic electrode structure 402a and the output IDT 404 comprises a second periodic electrode structure 404a. The input IDT 402 is provided at a first location of the piezoelectric substrate 406 and the output IDT 404 is provided at a second location of the piezoelectric substrate 406 such that there is a space between the input IDT 402 and the output IDT 404, 100421 Those skilled in the art will appreciate that a piezoelectric material can generate an electric charge in response to mechanical stress. Furthermore, a piezoelectric material can deform and generate mechanical stress in response to an applied electric field. An alternating electrical signal can be applied to the input IDT 402 such that adjacent electrodes have opposite polarities and the polarity of each electrode alternates according to the applied alternating electrical signal. Such a signal causes there to be a region of compressive stress next to a region of tensile stress, and each region alternates between compressive and tensile stress. As a result of this alternating compressive and tensile stress, there is generated a mechanical wave. This mechanical wave is what is referred to as a surface acoustic wave (SAW), as described above. SAWs in the SAW sensor element 302 are generated at the resonant frequency of the SAW sensor element 302.

100431 In the example of Figure 4, the SAW travels from the input IDT 402 to the output IDT 404. The alternating regions of compressive and tensile stress caused by the SAW at the output IDT cause there to be alternating electric fields. These alternating electric fields generate an electrical signal in the output IDT such that the polarities of adjacent electrodes of the output IDT 404 alternate in the manner described above for the input IDT 402. In other words, an electrical signal is generated at the output IDT 404 by the reverse of the process which took place at the input IDT 402 to generate the SAW from the input electrical signal.

100441 As previously described, the physical properties (such as temperature, for example) of the SAW sensor element may be determined based on the output signal The characteristics of the SAW in the SAW sensor element 302 depend on the physical properties of the SAW sensor element such as temperature. Therefore, by detecting the characteristics of the SAW, the temperature of the SAW sensor element 302 can be determined For example, the characteristics of the SAW are detected using the output signal generated by the output IDT 404 in response to an interrogation signal received at the input IDT 402 100451 Various characteristics of the SAW may be detected. For example, a delay relating to the transmission of the interrogation signal and receipt of the output signal in response from the temperature sensing device 300, a phase shift response of the SAW sensor element 302, and/or a resonant frequency of the SAW sensor element 302 may be detected. For example, the frequency of the output signal corresponds to the frequency of the SAW and therefore the resonant frequency of the SAW sensor element 302. A desired physical property of the SAW sensor element 302 (such as temperature) may then be determined from the detected characteristic of the SAW sensor element 302.

100461 A predefined relationship between the detected characteristic (for example, the resonant frequency) of the SAW sensor element 302 and the temperature of the SAW sensor element 302 may be stored in a computer readable memory (for example, in the computing system 106) on the aircraft 100, for example. The predefined relationship specifies what the detected characteristic of the SAW sensor element 302 is expected to be at various different temperatures (for example, obtained from calibration and/or testing of the SAW sensor element 302). For example, from a given resonant frequency, the temperature of the SAW sensor element 302 is determined from the predefined relationship. The predefined relationship may be stored in the form of a look-up table, rule, correlation equation, graph, etc. 100471 The predefined relationship may be determined by performing calibration or other test on the SAW sensor element 302. For example, test may be performed to cause the SAW sensor element 302 to resonate at different temperatures and determine the resonant frequencies at those temperature in order to establish the predefined relationship 100481 As previously described, the temperature sensing device 300 is attached to one of the brake discs 202. In the example of Figure 2, the temperature sensing device is attached to one of the stators 210. Therefore, the temperature of the SAW sensor element 302 corresponds to the temperature of the brake disc to which it is attached.

100491 The interrogation signal may be wirelessly received by the temperature sensing device 300. The temperature sensing device 300 may comprise (as in the example of Figure 3) a sensor antenna 304 configured to wirelessly receive the interrogation signal, and supply the interrogation signal to the SAW sensor element 302. For example, the sensor antenna 304 receives the interrogation signal in the form of radio waves and converts the radio waves into an electrical signal. The SAW sensor element may be configured to, responsive to the interrogation signal, output a signal as a response (the described output signal), the output signal indicative of the resonant frequency of the SAW sensor element 302, to the sensor antenna 304. For example, the sensor antenna 304 may be configured to wirelessly transmit the output signal. For example, the sensor antenna 304 converts the electrical output signal into radio waves.

100501 For example, the sensor antenna 304 supplies the interrogation signal to the input IDT 402 of the SAW sensor element 302. The interrogation signal as received at the input IDT 402 is an alternating electrical signal which causes the input IDT 402 to generate a SAW as previously described. The SAW sensor element 302 provides an output signal (generated by the output IDT 404 as previously described). For example, the output signal is supplied from the output IDT 404 to the sensor antenna 304. The sensor antenna 304 transmits the output signal. For example, the sensor antenna 304 is electrically coupled to the input [DT 402 and the output IDT 404. The origin of the interrogation signal and the components which receive and process the output signal are described later.

100511 A change in temperature of the SAW sensor element 302 causes a change in the resonant frequency. For example, as the temperature of the SAW sensor element 302 increases, the resonant frequency of the SAW sensor element decreases. The frequency of the SAW depends on the spacing between the electrodes of the IDTs. The spacing between adjacent electrodes is referred to as the pitch of the EDT in question The pitch determines the wavelength of the SAW generated by the IDT. The pitch is equal to half of the wavelength of the SAW generated by the IDT Therefore, the desired frequency resonant frequency of the SAW sensor element 100521 The frequency of the SAW depends on the propagation velocity of the SAW and the wavelength of the SAW according to Equation (1) below.

vs. f = (1)

A

100531 In Equation (1), f represents the frequency of the SAW, 14 represents the propagation velocity of the SAW in the SAW sensor element in question, and A represents the wavelength of the SAW.

100541 The frequency of the SAWs generated in the SAW sensor element 302 can be referred to as the resonant frequency of the SAW sensor element. It will be appreciated that, for a given propagation velocity of the SAW in the SAW sensor element 302, the resonant frequency of the SAW sensor element 302 can be configured by selecting an appropriate pitch for the IDTs of the SAW sensor element 302.

100551 The temperature of the SAW sensor element 302 may be determined by detecting the resonant frequency of the SAW sensor element 302 as indicated by the output signal.

100561 Figure 5 schematically illustrates an example of a temperature sensing system 500 for sensing aircraft wheel brake temperature. The temperature sensing system 500 comprises the temperature sensing device 300 according to any of the described examples. The temperature sensing system 500 also comprises a wireless relay device 502 for delivering the interrogation signal for wirelessly interrogating the SAW sensor element 302. The wireless relay device 502 delivers the interrogation signal by wirelessly transmitting the interrogation signal to the temperature sensing device 300. The wireless relay device 502 also wirelessly receives the described output signal. The wireless relay device 502 is hereafter simply referred to as the relay 502.

100571 In some examples, the relay 502 comprises a relay antenna 504. The relay antenna wirelessly transmits the interrogation signal and wirelessly receives the output signal. In some such examples, the relay 502 is simply a device for communicating wirelessly with the temperature sensing device 300. As described, the temperature sensing device 300 may be attached to one of the brake discs 202. The relay 502 may be attached to a component of the brake 200 or wheel 104 such that it can wirelessly communicate with the temperature sensing device 300 attached to a brake disc. For example, the relay 502 may be mounted so as to maintain line of sight with the temperature sensing device 300.

100581 The wireless communication between the temperature sensing device 300 and the relay 502 can be implemented, for example, by electromagnetic, inductive or capacitive coupling of the relay 502 to the temperature sensing device 300. For example, each of the sensor antenna 304 and the relay antenna 504 may be configured to convert electrical signals to radio waves and vice versa, with the radio waves being transmitted between the respective antennas.

100591 In some examples, the temperature sensing device 300 is attached to the first stator 210a and the relay 502 is attached to the torque tube 218 to which the first stator 210a is keyed. In such examples, the relay 502 is attached to the torque tube at a position so as to be in the line of sight of the temperature sensing device 300 on the first stator 210a. In other examples, the temperature sensing device 300 may be attached to a different brake disc or a different component of the brake 200, and the relay 502 may be attached to an appropriate location to maintain line of sight with the temperature sensing device 300.

100601 The temperature sensing system 500 may comprise an interrogation apparatus 506. The interrogation apparatus 506 may form part of the computing system 106 of the aircraft 100. In such examples, the interrogation apparatus 506 forms a communication link (which may be wireless or wired) with the relay 502. The interrogation apparatus 506 comprises a controller 508 configured to provide the interrogation signal. For example, the controller 508 may provide the interrogation signal based on a command signal received from another component of the computing system 106. The command signal may comprise the interrogation signal, and the interrogation signal may simply be retransmitted towards to the relay 502. In other examples, the command signal may be an instruction for the controller 508 to generate the interrogation signal.

100611 In the example of Figure 5, the interrogation apparatus 506 comprises a transceiver 510 for transmitting the interrogation signal to the relay 502 and receiving the described output signal from the relay 502. The transceiver 510 may communicate with the relay 502 via a wired communication link or wirelessly. For example, for wireless communication, respective antennas may be provided as part of the relay 502 and the interrogation apparatus 506.

100621 The SAW sensor element 302 has a resonant frequency within a frequency range between 175 megahertz (MHz) and 190MHz at a predetermined temperature. A frequency range between 175MHz and 190MHz is not limited to a range having 175MHz as a lower limit and 190MHz as an upper limit. For example, the frequency range may be any range that falls between 175 MHz and 190 MHz (for example, 175 MHz to 180 MHz, 176 MHz to 188 MI-lz, 180 MHz to 190 MHz, etc.). In some examples, the resonant frequency of the SAW sensor element 302 is within the frequency range when the temperature of the SAW sensor element 302 is within a predetermined temperature range (for example, 24°C to 1000°C) 10063] Figure 6 is a simplified schematic side cross-sectional view of a temperature sensing device 300. In examples, the temperature sensing device 300 comprises a surface acoustic wave (SAW) sensor element 302 mounted in a sensor element slot 602 in a sensing device substrate 606. In this example, the sensor antenna 304 on a surface 610 of the sensing device substrate 606.

100641 In some examples, there is provided the method 700 illustrated in the flow diagram of Figure 7. The method 700 is an example of a method of manufacturing a temperature sensing device (such as the described temperature sensing device 300) for sensing aircraft wheel brake temperature. At block 602 of the method 700, a sensor element slot (such as the described sensor element slot 602) is formed (for example, by cutting) in a sensing device substrate.

100651 Figure 8 is a simplified schematic side cross section of an example sensing device substrate 606 The sensing device substrate 606 may be a layer of a ceramic material The sensing device substrate is the result of block 702 being performed.

100661 The sensing device substrate 606 comprises the sensor element slot 602. The sensor element slot 602 is cut so as to accommodate the SAW sensor element 302. For example, the sensor element slot 602 is shaped so as to receive the SAW sensor element 302 within the sensor element slot 602. Providing the sensor element slot 602 advantageously provides a way to secure the SAW sensor element to the sensing device substrate 606. It will be appreciated that the SAW sensor element 302 may be produced separately to other components of the temperature sensing device 300, and subsequently assembled with those other components to provide the temperature sensing device 300. Providing the sensor element slot 602 provides a specific position on the sensing device substrate 606 for the SAW sensor element 302 to be installed. For example, the sensor element slot 602 is formed at a specific position on the sensing device substrate for each iteration of the sensing device substrate 606. A specific position for the SAW sensor element 302 makes repeated production of the temperature sensing device 300 more efficient because the SAW sensor element 302 is in the same position on the sensing device substrate 606 and can be electrically coupled to other electronic components of the temperature sensing device 300 in a standardized manner. Providing the sensor element slot 602 also advantageously aides in securely fixing the SAW sensor element 302 to the sensing device substrate 606. Accordingly, the SAW sensor element 302 mounted in the sensor element slot 602 is less likely to undergo movement relative to the sensing device substrate 606. For example, such movement is less likely when vibration and the like is applied to the temperature sensing device 300.

100671 In some examples, the sensor element slot 602 is cut so as to firmly hold the SAW sensor element 302 such that movement of the SAW sensor element 302 due to application of vibration and/or physical shock to the temperature sensing device (comprising the sensing device substrate 606) is inhibited. For example, the dimensions of the sensor element slot 602 are closely matched to the dimensions of the SAW sensor element 302. Closely matched dimensions mean that significant gaps between edges of the SAW sensor element 302 and the sensor element slot 602 can be avoided to reduce or inhibit movement of the SAW sensor element 302 within the sensor element slot 602 when mounted.

100681 In some examples, the sensor element slot 602 is cut using a laser cutting technique. It will be appreciated that laser cutting is a high precision technique in that cutting precision may be in the order of micrometres (for example, laser cutting may provide dimensions of the sensor element slot 602 to within a few micrometre of specified dimensions). Using a laser cutting technique may provide the sensor element slot 602 so that the SAW sensor element 302 is tightly fitting (for example press-fitting) in the sensor element slot 602 is a predictable manner. Those skilled in the art will appreciate that laser cutting apparatus may be controlled by a computer to produce the sensor element slot 602 according to desired dimensions. For example, a computer may control movement of the laser and properties of the laser (power, beam width and the like).

100691 In some examples, other high precision cutting techniques (such as a plasma cutting technique and the like) may be used to provide the sensor element slot 602 to firmly hold the SAW sensor element 302.

100701 At block 704 of the method 700, the SAW sensor element 302 is mounted in the sensor element slot 602. For example, the SAW sensor element 302 is positioned into the sensor element slot 602 such that the edges of the SAW sensor element 302 are held by inner surfaces of the sensor element slot 602. The SAW sensor element 302 is not shown in the example of Figure 8.

100711 in some examples, additional ways of securing the SAW sensor element 302 in the sensor element slot 602 may be used. For example, the parts of the SAW sensor element 302 in contact with surfaces within the sensor element slot 602 may be adhered to those surface (for example, using a ceramic adhesive or otherwise).

100721 At block 706 of the method 700, the temperature sensing device 300 comprising the sensing device substrate 606 with the SAW sensor element 302 mounted in the sensor element slot 602 is provided. For example, the sensing device substrate 606 resulting from performing block 704 is included in the temperature sensing device 300. For example, providing the temperature sensing device 300 at block 706 includes all the actions for providing any example of the temperature sensing device 300. For example, block 706 may include providing the sensor antenna 304, etc. 100731 The result of performing the method 700 is the provision of a temperature sensing device for sensing aircraft wheel brake temperature, which comprises a SAW sensor element mounted in a sensor element slot in a sensing device substrate 100741 In some examples, the method 700 comprises producing the sensor antenna 304 on the surface 610 of the sensing device substrate 606. The sensor antenna 304 may be produced on the surface 610 according to any method suitable for producing an antenna on a substrate surface (for example, printing the antenna). In such examples, the method 700 provides the temperature sensing device 300 comprising the sensor antenna 304 on the surface 610 of the sensing device substrate 606. The temperature sensing device 300 comprises a housing, packaged construction or the like 612 (represented in dashed line in Figure 6) which encloses the sensor antenna 304. Accordingly, the sensor antenna 304 is not an external component of the temperature sensing device 300, but an internal component.

100751 In some examples, the method 700 comprises electrically coupling (for example, by electrically connecting) the sensor antenna 304 to the SAW sensor element 302. In such examples, the method 700 provides the temperature sensing device 300 in which the sensor antenna 304 is electrically coupled to the SAW sensor element 302. For example, electrical connections are formed between the sensor antenna 304 on the surface 610 and the SAW sensor element 302 mounted in the sensor element slot 602. It will be appreciated that one or more electrical connections between the sensor antenna 304 and the SAW sensor element 302 provide for passing signals (such as the described interrogation signal and the described output signal) therebetween. Electrical connections between the sensor antenna 304 and the SAW sensor element 302 may be formed via a tuning structure (not shown) which matches the impedance of the SAW sensor element 302 and the sensor antenna 304.

100761 Certain components are described as being electrically coupled to other components. In some examples, components may be electrically coupled by virtue of an electrical connection. Those skilled in the art will appreciate that electronic components may also be capacitively or inductively coupled, for example. The type of electrical coupling depends on the characteristics of the electronic components and the particular application.

100771 It should be noted that the Figures show simplified schematic views for the purpose of illustration. The Figures are intended to illustrate the described concepts and are not intended to convey dimensions, relative sizes of components and the like. In some cases, certain components are not shown for simplicity, as will be appreciated by those skilled in the art.

100781 Although the invention has been described above with reference to one or more preferred examples, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMS1. A method of manufacturing a temperature sensing device for sensing aircraft wheel brake temperature, the method comprising: forming a sensor element slot in a sensing device substrate; mounting the SAW sensor element in the sensor element slot; and providing the temperature sensing device comprising the sensing device substrate with the SAW sensor element mounted in the sensor element slot.
The method according to claim 1 comprising: producing a sensor antenna on a surface of the sensing device substrate.
3. The method according to claim 2 comprising: electrically coupling the sensor antenna to the SAW sensor element.
The method according to any one of the preceding claims, wherein: the sensor element slot is cut using a laser cutting technique.
The method according to any one of the preceding claims, wherein: the sensor element slot is cut so as to firmly hold the SAW sensor element such that movement of the SAW sensor element due to application of vibration and/or physical shock to the temperature sensing device is inhibited.
6. A temperature sensing device for sensing aircraft wheel brake temperature, the temperature sensing device comprising: a surface acoustic wave, SAW, sensor element mounted in a sensor element slot in a sensing device substrate.
The temperature sensing device according to claim 6, wherein: the sensor element slot is cut so as to firmly hold the SAW sensor element such that movement of the SAW sensor element due to application of vibration and/or physical shock to the temperature sensing device is inhibited.
The temperature sensing device according to claim 6 or claim 7, wherein: the sensor element slot is cut using a laser cutting technique.
9. The temperature sensing device according to any one of claims 6 to 8 comprising: a sensor antenna on a surface of the sensing device substrate.
10. The temperature sensing device according to claim 9, wherein: the sensor antenna is electrically coupled to the SAW sensor element.
11. An aircraft wheel brake comprising the temperature sensing device according to any one of claims 6 to 10.
12. The aircraft wheel brake according to claim 11, wherein: the temperature sensing device is attached to a brake disc of the aircraft wheel brake
13. An aircraft comprising the aircraft wheel brake according to claim 11 or claim 12.