TIRE PRESSURE GAUGE

Description

[0001] The present invention relates to a device for measuring the pressure of an aircraft wheel tire. BACKGROUND OF THE INVENTION

[0002] It is useful to know the tire pressures of the different wheels of an aircraft's landing gear during different phases of aircraft operation (ground movement phase, pre-landing approach phase for example) or as part of maintenance operations.

[0003] For this purpose, the aircraft is typically equipped with an automatic tire pressure monitoring system. This system, known as a TPMS (Tire Pressure Monitoring System), includes a pressure sensor mounted on the rim of each wheel. The pressure sensor is connected to an onboard data processing system, providing pilots with a real-time display of tire pressure in the cockpit during various aircraft operating phases. During maintenance operations, operators can also consult this display to obtain the necessary information.

[0004] With reference to the figure 1 The pressure sensor C is typically fitted to one end of a self-sealing valve V mounted on the rim G to allow removal of the pressure sensor C without significant loss of tire pressure. The valve V is screwed into a bore that communicates through the rim G with the internal volume of the tire. The pressure sensor C is held in place within the valve V by a locking ring B screwed onto the valve V, and a spring washer R compressed between a base of the locking ring B and one end of the pressure sensor C. This spring washer compensates for manufacturing clearances and limits loosening of the locking ring B during operation. The pressure sensor C is powered and communicates with the data processing system via a cable H connecting the pressure sensor C to a rotary contact installed in the wheel hub.

[0005] The main disadvantage of such an arrangement of the pressure sensor C lies in the fact that tightening the locking ring B tends to cause the pressure sensor C to rotate around its axis and thus to cause a twist in the cable H which, under stress, may have its life limited.

[0006] Moreover, the use of a spring washer has the effect of seizing the locking ring B, which tends to make maintenance difficult.

[0007] Prior art devices are described in documents WO 2016 / 090218 A1, EP 3 984 787 A1 and US 1 487 851 A. SUBJECT OF THE INVENTION

[0008] The invention therefore aims to provide a device for measuring the pressure of a tire which makes it possible to overcome at least in part the aforementioned disadvantages. SUMMARY OF THE INVENTION

[0009] To this end, the invention proposes a device for measuring the pressure of a gas contained in a tire mounted on a wheel rim, the device comprising: a valve, adapted to be mounted on the rim, comprising a first gas flow channel, a pin mounted movable in translation in the first channel between an open position and a closing position of the first channel, and a spring for returning the pin to the closing position; an intermediate body which is mounted on the valve and which delimits a second channel extending the first channel and receiving a rod for fixing the intermediate body to the valve, the fixing rod having a first end protruding into the first channel to bring the pin from the closing position to the open position, a second end accessible from outside the second channel, and an intermediate portion closing the second channel;a pressure sensor received in a third channel of the intermediate body, the third channel opening into the second channel between the first end and the intermediate portion of the fixing rod, being inclined relative to the second channel; and means for retaining the pressure sensor in the third channel of the intermediate body.

[0010] Thus, the sensor can be mounted on the intermediate body while it is not yet attached to the valve and can be positioned in any orientation. The intermediate body is then attached to the valve using the fixing rod, which performs a triple function: securing the intermediate body to the valve, blocking the second channel, and moving the pin into position for the sensor.

[0011] According to a particular feature, the device includes means for angular indexing of the intermediate body relative to the valve.

[0012] In particular, the angular indexing means include at least two pins carried by the valve and arranged to cooperate with holes provided in the intermediate body.

[0013] The angular indexing mechanism of the intermediate body relative to the valve prevents any rotation of said intermediate body relative to the valve, thereby limiting stress on the cable(s) extending from the pressure sensor. It also ensures reproducibility of the angular position of the intermediate body relative to the valve, thus guaranteeing correct positioning of the sensor relative to the rim and facilitating its inspection.

[0014] In particular, the pins and holes are arranged to provide at least two possible angular positions of the intermediate body relative to the valve.

[0015] In particular, the first end of the fixing rod includes a drilling forming a fourth gas flow channel.

[0016] According to another particular feature, the first end of the fixing rod includes a thread engaged in a tapping of the first channel.

[0017] According to another particular feature, the retaining means include a locking ring arranged to be fixed to the intermediate body by trapping the pressure sensor in the third channel.

[0018] The invention also relates to an aircraft wheel comprising a rim on which a tire is mounted and such a device.

[0019] The invention also relates to an aircraft landing gear comprising at least one such wheel.

[0020] The invention further relates to an aircraft comprising at least one such landing gear. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention will be better understood in light of the following description, which is purely illustrative and not limiting, and should be read in conjunction with the accompanying drawings, among which: There figure 1 is an axial cross-sectional view of a prior art device for measuring the pressure of an aircraft wheel tire; The figure 2 is a simplified representation of an aircraft comprising main landing gear having wheels equipped with the pressure measuring device according to the invention; The figure 3 is an axial cross-sectional view of one of the wheels of the aircraft illustrated in the figure 2 ; There figure 4 is a perspective view of the measuring device schematically illustrated in the figure 3 ; There figure 5 is a partial view of the measuring device illustrated in the figure 4 ; There figure 6 is an axial cross-sectional view of the measuring device illustrated in the figure 4 ; There figure 7 is a perspective view of a variant of the valve of the measuring device illustrated in the figure 4 . DETAILED DESCRIPTION OF THE INVENTION

[0022] With reference to the figure 2 The invention applies to an aircraft A comprising main landing gear P, each having a leg J ​​with a first end articulated to a structure of the aircraft A and a second end provided with an axle E. Each axle E is provided, as illustrated in the figure 3 of a wheel R comprising an annular rim 1 on which a tire 2 is mounted. In a known manner, the tire 2, together with the rim 1, defines a volume V in which a gas is trapped. The rim 1 is connected by a disc 3 to a hub 4 mounted to rotate, around an axis X, on a free end of the axle E by means of bearings 5.

[0023] Inside a free end of the axle E is arranged a tachometer 10 intended for tracking the rotation of the wheel 1. The tachometer 10 comprises a fixed part 11 attached to the axle E, and a movable part 12 rotating relative to the fixed part 11, substantially around the axis X.

[0024] A cup 20 forming a hood is attached to the rim 1 along the X-axis. The cup 20 comprises a base 21 surrounded by a cylindrical side wall 22. The side wall 22 has an external peripheral flange bearing against the rim 1, through which the cup 20 is fixed to the rim 1 by means of screws 23, so that said cup 20 is rotationally fixed to the wheel 1.

[0025] The cup 20 further includes a sleeve 24 which extends substantially along the X-axis projecting from the cover 21 towards the inside of the axle E. The sleeve 24 has a central grooved hole receiving a grooved rod 25 extending axially from the sleeve 24. The free end of the rod 25 is arranged to be connected to the moving part 12 of the tachometer 10 by means of a rotating coupling mechanism 26 adapted to compensate for any axial offset between the axis of rotation of the moving part 12 of the tachometer 10 and the axis of rotation of the rod 25, and therefore of the cup 20. The coupling mechanism 26 is, for example, a rubber buffer fixed on one side to the moving part 12 of the tachometer 10, and on the other side to the grooved rod 25.

[0026] The rim 1 comprises an inner surface 6 of substantially frustoconical shape extending from the disc 3 to a distal end of the rim 1. A pressure-measuring channel 7 extends within the rim 1 in a plane passing through the wheel's axis of rotation X. The channel 7 is substantially straight and has a first end opening into the volume V and a second end opening onto the inner surface 6. The second end of the channel 7 has an internally threaded bore 8 through which a device 100 is fixed for measuring the pressure of the gas trapped in the volume V delimited by the rim 1 and the tire 2.

[0027] With reference to the figure 4 , the device 100 includes a self-sealing valve 110 screwed into the bore 8 of the rim 1, an intermediate sensor support body 120 engaged on the valve 110 and held in position on said valve 110 by means of a fixing rod 130 screwed into the valve 110, and a pressure sensor 140 mounted in the sensor support 120 and held in position in the sensor support 120 by means of a locking ring 150 screwed onto the sensor support 120.

[0028] With reference to the figure 6 The valve 110 comprises a body 111 of generally tubular shape which delimits a channel 112 for the passage of the gas stored in the volume V. The body 111 extends along an axis X 110 and includes a first section 111.1 for connection with the rim 1 and a second section 111.2 for connection with the sensor support 120. The first and second sections 111.1, 111.2 are separated by an external flange 111.3 which has a first face transverse to the axis X 110 forming a stop for screwing the valve 110 into the bore 8 of the rim 1 and, opposite, a second face transverse to the axis X 110 forming a stop for engaging the sensor support 120 on the second section 111.2 of the body 111 along the axis X 110.

[0029] The first section 111.1 of the body 111 is externally provided with a thread arranged to cooperate with the thread of the bore 8 of the rim 1 so as to allow the valve 110 to be screwed onto the rim 1. The first section 111.1 is further externally provided with a first annular groove formed between the collar 111.3 and the thread of said first section 111.1. The first groove receives a first annular sealing gasket 113 intended to ensure sealing between the first section 111.1 of the body 111 and the bore 8 of the rim 1.

[0030] The first section 111.1 of the body 111 defines a first end portion of the channel 112, within which is housed a valve mechanism 114 that allows or prevents the gas trapped in volume V from flowing through the channel 112. The valve mechanism 114 comprises a pin 115 (or flap) mounted to move in translation, substantially about the X-axis 110, between an open position in which it is offset by one seat and allows the gas trapped in volume V to flow through the channel 112, and a closed position in which it bears against a seat and prevents said gas from flowing through said channel 112. A spring 116 returns the pin 115 to its closed position, and a safety vent is provided at the thread of the first section 111.1 to open into the valve mechanism 114 so as to allow the gas to escape from volume V when an operator unscrews valve 110 while the gas is still under pressure.The valve mechanism 114 being well known from the prior art, it will not be described in further detail here.

[0031] The second section 111.2 of the body 111 is provided externally with a second annular groove formed at a free end of said second section 111.2. The second groove receives a second annular sealing gasket 117 intended to ensure sealing between the second section 111.2 of the body 111 and the sensor support 120.

[0032] The second section 111.2 delimits a second end portion of the channel 112 which is partially internally threaded and into which the fixing rod 130 is screwed.

[0033] The collar 111.3 has a generally hexagonal cross-section along the X-axis 110 and includes two cylindrical holes 118 with axes parallel to the X-axis 110, opening onto the second transverse face of the collar 111.3 facing the sensor support 120. The holes 118 are identical and diametrically opposite with respect to the X-axis 110. Each hole 118 receives an anti-rotation pin 119 extending beyond the collar 111.3. The pins 119 are identical and have a diameter slightly larger than that of the holes 118, so that the pins 119 are press-fitted into the holes 118.

[0034] The sensor support 120 includes a main body portion 121 which has a generally tubular shape and which extends substantially coaxially to the valve 110 along an X axis 120 substantially coincident with the X axis 110. The main body portion 121 delimits a channel 122 which has a first end having a first bore 123 shaped to receive the second section 111.2 of the valve body 111, and a second end, opposite to the first end, having a second bore 124 shaped to receive a portion of the fixing stem 130.A central portion of the channel 122 provides fluidic communication between the first bore 123 and the second bore 124, and includes a thread into which the retaining rod 130 can be screwed so that said retaining rod 130 extends through the central portion and remains fixed to the sensor support 120 when unscrewed from the valve body 111 (which prevents loss of the retaining rod 130).

[0035] The first bore 123 has an internal diameter slightly larger than an external diameter of the second section 111.2 of the valve body 111 so as to allow the sensor support 120 to be fitted onto said second section 111.2, the second sealing gasket 117 being intended to ensure sealing between said second section 111.2 and said first bore 123.

[0036] The end of the main body part 121 facing the collar 111.3 of the valve body 111 includes an external collar 125 having a lateral face forming a stop for the fitting of the sensor support 120 onto the second section 111.2 of the valve body 111.

[0037] With reference to the figure 5 The collar 125 has a plurality of identical holes 126 arranged to cooperate in pairs with the pins 119 carried by the valve body 111. The holes 126 are cylindrical in shape with an axis parallel to the X-axis 120 and open onto the lateral face of the collar 125 facing the flange 111.3 of the valve body 111. The holes 126 are symmetrically distributed around the X-axis 110, in the vicinity of an outer periphery of the collar 125, and have a diameter slightly larger than that of the pins 119. The centers of the holes 126 lie on the same circle whose center is located on the X-axis 120, the holes 126 being diametrically opposed in pairs. The pins 119 and the holes 126 thus form angular indexing means for the sensor support 120 on the valve body 111, but also means for locking the said sensor support 120 against rotation with respect to the valve body 111, around the X axis 110.It should be noted in particular that the holes 126 offer, around the X axis 110, a plurality of possible angular positions of the sensor support 120 relative to the valve body 111.

[0038] The sensor support 120 is held fitted onto the valve body 111 via the fixing rod 130 which has a generally cylindrical shape and which extends along an X axis 130 substantially coincident with the X axis 120 by passing through the main body part 121 of said sensor support 120.

[0039] The 130 fixing rod includes: a first end 131 externally provided with a thread arranged to cooperate with the thread of the central portion of the channel 122 of the sensor support 120 and the internal thread of the second section 111.2 of the valve body 111, a second end 132 projecting from the main body part 121, and an intermediate portion 132.1 arranged in the vicinity of the second end 132 to obstruct the second bore 124 of the sensor support 120.

[0040] The first end 131 of the retaining rod 130 has a front face 133 arranged to bear against one end of the pin 115 and to move said pin 115 from the closed position to the open position when the retaining rod 130 is screwed into the valve body 111. The first end 131 of the retaining rod 130 also has a bore extending in a plane passing through the X-axis 130 and opening on either side of the thread of the retaining rod 130 to form a channel 134 ensuring fluid communication between the channel 112 of the valve body 111 and the channel 122 of the sensor support 120, thus allowing the gas trapped in the volume V to pass through the valve body 111 and reach the first bore 123 of the sensor support 120. The channel 134 is straight and extends along an oblique axis relative to the X axis 130.

[0041] The second end 132 of the retaining rod 130 is provided with a recess 132.2 for cooperating with a tool for rotating the retaining rod 130 about its X-axis 130 and includes a base 132.3 that acts as a stop for screwing the retaining rod 130 into the valve body 111. The base 132.3 separates the second end 132 from the cylindrical intermediate portion 132.1 received in the second bore 124 of the main body portion 121 of the sensor support 120. The intermediate portion 132.1 is provided externally with an annular groove that receives an annular sealing gasket 135 for sealing between said intermediate portion 132.1 and the second bore 124 of the sensor support 120.

[0042] The sensor support 120 further includes a secondary body part 127 of generally tubular shape which extends outward from the main body part 121 along an X-axis 120, oblique to the X-axis 120. The secondary body part 127 defines a channel 128 having a first end opening outside the sensor support 120 and a second end, opposite the first end, opening into the channel 122 of the main body part 121 between the sealing gasket 117 and a bottom of the first bore 123 of said main body part 121. The channel 128 is stepped and thus comprises three successive bores 128.1, 128.2, 128.3 forming a housing in which the pressure sensor 140 is fitted: the first bore 128.1 opens outside the sensor support 120, the second bore 128.2 opens into the first bore 128.1 and has a diameter greater than that of said first bore 128.1, and the third bore 128.3 opens into the second bore 128.2 and has a diameter greater than that of said second bore 128.2.

[0043] The pressure sensor 140 is generally cylindrical in shape and extends from the end of a cable 143 projecting from the cup 20. The pressure sensor 140 is securely fastened in the secondary body part 127 of the sensor support 120 by means of the locking ring 150 and a sealing gasket 144 carried by said pressure sensor 140. The locking ring 150 is screwed onto an external thread provided at a free end of the secondary body part 127 of the sensor support 120, and includes an internal shoulder 151 arranged to cooperate with a first external shoulder 141 of the pressure sensor 140 so as to bring a second external shoulder 142 of said pressure sensor 140 abutting said free end of the secondary body part 127. The sealing gasket 144 provides a seal between the pressure sensor 140 and the second bore 128.2 of the secondary body part 127 of the sensor support 120.

[0044] The pressure sensor 140 is of the piezoelectric type and includes a pressure probe 145 adapted to measure pressure within the useful range of pressures found inside tires. The pressure probe 145 is connected, via cable 143, to a signal processing and control module 146 for the pressure probe 145. The module 146 comprises a printed circuit board located on the bottom 21 of the cup 20, around the socket 24.

[0045] A processing unit 147 is attached to a fixed part of the landing gear or the aircraft body and is adapted for operation, and in particular for displaying pressure measurements taken by means of the pressure sensor 140. Module 146 and the processing unit 147 are connected to each other by means of communication (not shown) adapted to establish radio frequency transmission, i.e., via microwave links, between said module 146 and said processing unit 147. This transmission is bidirectional, meaning that each entity can send and receive information. The communication means are also adapted to transmit, via microwave links, the electrical energy necessary for the operation of the pressure sensor 140.

[0046] The sensor support 120, the sensor 140, and the locking ring 150 form an assembly that can be detached from the valve 110 simply by unscrewing and removing the retaining rod 130. Unscrewing the retaining rod 130 causes the pin 115 of the valve 110 to move from the open position to the closed position (before the threads of the retaining rod 130 are completely disengaged from the tapped hole), which allows the assembly formed by the sensor support 120, the sensor 140, and the locking ring 150 to be removed without deflating the tire 2. Therefore, it is not necessary to unscrew the locking ring 150 during maintenance. The pins 119 carried by the valve 110 and the holes 126 in the sensor support 120 allow to: to position angularly the sensor support 120 (and therefore the sensor 140) vis-à-vis the valve 110 along the X 100 axis, the holes 126 offering several possible angular positions; and to rotationally secure the valve 110 and the sensor support 120 so as to prevent any rotation of said valve support 120 (and therefore of the sensor 140) relative to said valve 110 around the X 100, X 120 axis.

[0047] The use of a wire brake type safety device and the determination of a tightening torque for the fixing rod 130 and the locking ring 150 allows for better control and reproducibility of the assembly of the device 100.

[0048] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0049] Although device 100 applies here to the R wheels equipping the main landing gear P, it can also apply to the wheels equipping the nose landing gear of aircraft A illustrated in the figure 1 , and more generally to any wheel equipping a lander.

[0050] Although device 100 applies here to an aircraft wheel, it can more generally be applied to any vehicle equipped with a wheel fitted with a tire trapping a gas.

[0051] The number of pins 119 may be greater than two. Preferably, the pins 119 are evenly distributed around the X axis 110.

[0052] The pins 119 and the holes 126 can be replaced by any other angular indexing means to ensure angular positioning of the sensor support 120 relative to the valve 110. For example, the second section 111.2 of the valve body 111 can include, as illustrated in the figure 7, a toothed ring 119' externally and adapted to cooperate with a toothed ring internally and received in the first bore 123 of the sensor support 120.

[0053] Although the secondary body part 127 of the sensor support 120 extends obliquely relative to the main body part 121 of said sensor support 120, it can also extend perpendicularly. Whether the secondary body part 127 extends obliquely or perpendicularly relative to the main body part 121, it is considered here that said secondary body part 127 is inclined relative to said main body part 121.

Claims

1. A device (100) for measuring the pressure of a gas contained in a tyre (2) mounted on a rim (1) of a wheel (R), the device comprising: - a valve (110), suitable for being mounted on the rim (1), comprising a first gas flow channel (112), a pin (115) mounted so as to be able to move in translation in the first channel between a position in which the first channel is open and a position in which it is closed, and a spring (116) for returning the pin to the closed position; the device being characterised by comprising: - an intermediate body (120) that is mounted on the valve and that delimits a second channel (122) extending the first channel and receiving a fastening rod (130) for fastening the intermediate body to the valve, the fastening rod having a first end projecting into the first channel for moving the pin from the closed position to the open position, a second end that can be accessed from outside the second channel, and an intermediate portion closing the second channel; - a pressure sensor (140) received in a third channel (128) of the intermediate body, the third channel leading into the second channel between the first end and the intermediate portion of the fastening rod, being inclined in relation to the second channel; and - means (150) for retaining the pressure sensor in the third channel of the intermediate body.

2. The device (100) according to claim 1, comprising means (119, 126) for indexing the intermediate body (120) at an angle in relation to the valve (110).

3. The device according to claim 2, wherein the angular indexing means (119, 126) comprise at least two studs (119) carried by the valve (110) and arranged to cooperate with holes (126) provided in the intermediate body (120).

4. The device (100) according to claim 3, wherein the studs (119) and the holes (126) are arranged to provide the intermediate body (120) with at least two possible angular positions in relation to the valve (110).

5. The device (100) according to any one of the preceding claims, wherein the first end of the fastening rod (130) comprises a piercing forming a fourth gas flow channel (134).

6. The device (100) according to any one of the preceding claims, wherein the first end of the fastening rod (130) comprises a thread engaged in a tapped hole of the first channel (112).

7. The device (100) according to any one of the preceding claims, wherein the retaining means comprise a locking ring (150) arranged to be fastened on the intermediate body (127), trapping the pressure sensor (140) in the third channel (128).

8. An aircraft wheel (R) comprising a rim (1) on which a tyre (2) is mounted and a device (100) according to any one of claims 1 to 7.

9. An aircraft landing gear (P) comprising at least one wheel (R) according to claim 8.

10. An aircraft (A) comprising at least one landing gear (P) according to claim 9.