Tire pressure measuring device

Abstract

The invention relates to a device (100) for measuring the pressure of a tyre (2) mounted on a rim (1), comprising:-a valve (110) mounted on the rim (1) and comprising a first channel (112), a pin (115) mounted so as to be translationally movable in the first channel between an open position and a blocked position; -an intermediate body (120) mounted on the valve and defining a second passage (122) extending the first passage and receiving an attachment rod (113300) for attaching the intermediate body to the valve, the attachment rod having a first end adapted to bring the pin from the blocked position into the open position, and an intermediate portion blocking the second passage; -a pressure sensor (140) housed in a third channel of the intermediate body, which third channel opens into the second channel; and-retaining means (150) for retaining the pressure sensor in the third channel of the intermediate body.

Description

Technical Field

[0001] The invention relates to a device for measuring the tire pressure of an aircraft wheel. Background Art

[0002] It is useful to know the pressure of the tires of the various wheels fitted to the landing gear of an aircraft during different operational phases of the aircraft (eg ground movement phase, approach phase before landing) or in maintenance operations.

[0003] To this end, aircraft are usually equipped with a system for automatically monitoring the internal pressure of the tires of the aircraft's wheels. This monitoring system is known as TPMS or Tire Pressure Monitoring System, which comprises, for each wheel, a pressure sensor mounted on the rim of the wheel. The pressure sensor is coupled to an onboard data processing system, making it possible to display the tire pressure during different operating phases of the aircraft to the pilot in real time in the cockpit. Thus, during maintenance operations, the operator can view this display to obtain the required information.

[0004] refer to Figure 1 , the pressure sensor C is usually assembled to one end of a self-sealing valve V mounted on the rim G, so as to allow the pressure sensor C to be removed without losing a lot of pressure from the tire. The valve V is screwed into a hole that communicates with the internal volume of the tire through the rim G. The pressure sensor C is kept assembled in the valve V by means of a locking ring B screwed onto the valve V and a spring washer R compressed between the base of the locking ring B and one end of the pressure sensor C, which helps to compensate for manufacturing clearances and limit the loosening of the locking ring B during operation. The pressure sensor C is powered and communicates with the data processing system by means of a cable H, which connects said pressure sensor C with a rotating contact mounted in the hub of the wheel.

[0005] The main disadvantage of arranging the pressure sensor C in this way is that tightening the locking ring B tends to cause the pressure sensor C to rotate about its axis, thereby twisting the cable H, the service life of which may be limited due to the stress.

[0006] Furthermore, the use of a spring washer may cause the locking ring B to become stuck, which tends to make maintenance difficult. Summary of the invention

[0007] The object of the present invention is therefore to propose a device for measuring tire pressure which at least partially overcomes the above-mentioned disadvantages.

[0008] To this end, the invention proposes a device for measuring the pressure of the gas contained in a tire mounted on a wheel rim, the device comprising:

[0009] - a valve adapted to be mounted on the rim, comprising a first gas flow channel, a pin mounted so as to be able to translate in the first channel between a position in which the first channel is open and a position in which the first channel is closed, and a spring for returning the pin to the closed position;

[0010] - an intermediate body mounted on the valve and defining a second channel extending the first channel and receiving a fastening rod for fastening the intermediate body to the valve, the fastening rod having a first end, a second end and a middle portion, the first end protruding into the first channel for moving the pin from the closed position to the open position, the second end being accessible from outside the second channel, the middle portion closing the second channel;

[0011] a pressure sensor received in a third channel of the intermediate body, the third channel opening into the second channel between the first end of the tightening rod and the intermediate portion, inclined relative to the second channel; and

[0012] - Means for retaining the pressure sensor in the third channel of the intermediate body.

[0013] Thus, the sensor can be mounted on the intermediate body, and can be brought into any orientation, when the intermediate body is not yet fastened to the valve. The intermediate body is then fastened to the valve by means of a fastening rod which performs three functions: fastening the intermediate body to the valve, closing the second channel, moving the pin instead of the sensor.

[0014] According to a particular feature, the device comprises means for indexing the intermediate body at an angle relative to the valve.

[0015] In a particular manner, the angular indexing means comprise at least two studs carried by the valve and arranged to cooperate with holes provided in the intermediate body.

[0016] Means for angularly indexing the intermediate body relative to the valve prevent the intermediate body from rotating relative to the valve, thus limiting the stress on the cable extending from the pressure sensor. They also make it possible to reproduce the angular position of the intermediate body relative to the valve, thus ensuring the correct positioning of the sensor relative to the rim and making it easier to control.

[0017] In a particular manner, the stud and the hole are arranged to provide the intermediate body with at least two possible angular positions relative to the valve.

[0018] In a particular manner, the first end of the fastening rod comprises a through hole forming a fourth gas flow channel.

[0019] According to another particular feature, the first end of the tightening rod comprises a thread engaging in the threaded hole of the first channel.

[0020] According to another particular feature, the retaining means comprise a locking ring arranged to be fastened to the intermediate body, trapping the pressure sensor in the third channel.

[0021] The invention also relates to an aircraft wheel comprising a rim on which a tyre is mounted and such a device.

[0022] The invention also relates to an aircraft landing gear comprising at least one such wheel.

[0023] The invention also relates to an aircraft comprising at least one such landing gear. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will be better understood from the following description, which is purely illustrative and not restrictive and should be read with reference to the accompanying drawings, in which:

[0025] Figure 1 is an axial cross-sectional view of an apparatus for measuring tire pressure of an aircraft wheel according to the prior art;

[0026] Figure 2 is a simplified representation of an aircraft comprising a main landing gear having wheels equipped with a pressure measuring device according to the invention;

[0027] Figure 3 yes Figure 2 An axial cross-sectional view of one of the wheels of the aircraft shown in;

[0028] Figure 4 yes Figure 3 A perspective view of the measuring device schematically shown in FIG.

[0029] Figure 5 yes Figure 4 A partial view of the measuring device shown in;

[0030] Figure 6 yes Figure 4 an axial cross-sectional view of the measuring device shown in; and

[0031] Figure 7 yes Figure 4 A perspective view of a valve variant of the measuring device is shown in FIG. DETAILED DESCRIPTION

[0032] refer to Figure 2 The invention is applied to an aircraft A, which comprises a main landing gear P, each of which comprises a leg J, the first end of which is hinged to the structure of the aircraft A and the second end of which is provided with an axle E. Figure 3As shown, each axle E is provided with a wheel R comprising an annular rim 1 on which is mounted a tyre 2. In a known manner, the tyre 2 and the rim 1 together delimit a volume V in which the gas is trapped. The rim 1 is connected by a web 3 to a hub 4 mounted for rotation about an axis X on the free end of the axle E by means of a bearing 5.

[0033] Inside the free end of the axle E there is arranged a tachometer 10 intended to monitor the rotation of the wheel 1. The tachometer 10 comprises a fixed part 11 fixed to the axle E and a movable part 12 rotatable substantially about the axis X relative to the fixed part 11.

[0034] A cap 20 forming a cover is fitted to the rim 1 along the axis X. The cap 20 comprises a base 21 surrounded by a cylindrical side wall 22. The side wall 22 comprises a peripheral flange bearing against the rim 1 and via which the cap 20 is fastened to the rim 1 by means of screws 23 so that it is constrained to rotate with the wheel 1.

[0035] The cap 20 also comprises a bushing 24 extending substantially along the axis X, projecting from the cover 21 towards the inside of the axle E. The bushing 24 has a splined central hole which houses a splined rod 25 extending axially from the bushing 24. The free end of the rod 25 is arranged to be linked to the movable part 12 of the tachometer 10 by means of a rotary coupling mechanism 26 designed to compensate for axial offsets between the axis of rotation of the movable part 12 of the tachometer 10 and the axis of rotation of the rod 25 (and thus of the cap 20). The coupling mechanism 26 is, for example, a rubber buffer fixed to the movable part 12 of the tachometer 10 and to the splined rod 25.

[0036] The rim 1 comprises a substantially frustoconical internal surface 6 extending from the web 3 towards the distal end of the rim 1. A pressure measurement channel 7 extends into the rim 1 in a plane passing through the axis of rotation X of the wheel. In this case, the channel 7 is substantially straight and comprises a first end opening into the volume V and a second end opening into the internal surface 6. The second end of the channel 7 comprises an internal threaded hole 8 via which the device 100 is fastened to measure the pressure of the gas trapped in the volume V delimited by the rim 1 and the tyre 2.

[0037] refer to Figure 4 The device 100 comprises: a self-sealing valve 110, which is screwed into the hole 8 in the rim 1; an intermediate sensor support 120, which is engaged on the valve 110 and is held in place on the valve 110 by means of a fastening rod 130 screwed into the valve 110; and a pressure sensor 140, which is mounted in the sensor support 120 and is held in place in the sensor support 120 by means of a locking ring 150 screwed onto the sensor support 120.

[0038] refer to Figure 6The valve 110 comprises a generally tubular body 111 defining a passage 112 for the passage of the gas stored in the volume V. The body 111 is oriented along an axis X. 110 The first section 111.1 and the second section 111.2 are separated by an outer flange 111.3, which has a transverse direction to the axis X. 110 The first face of the valve 110, which forms an abutment when the valve 110 is screwed into the hole 8 in the rim 1, has on the opposite side a transverse direction to the axis X 110 The second surface of the sensor support body 120 is arranged along the axis X 110 When engaging on the second section 11 . 12 of the body 111 , an abutment is formed.

[0039] The first section 111.1 of the body 111 is provided with a thread on the outside, which is arranged to cooperate with the thread of the hole 8 in the rim 1 to allow the valve 110 to be screwed onto the rim 1. The outside of the first section 111.1 is also provided with a first annular groove, which is arranged between the flange 111.3 and the thread of the first section 111.1. The first groove receives a first annular seal 113, which is intended to provide a tight seal between the first section 111.1 of the body 111 and the hole 8 in the rim 1.

[0040] The first section 111.1 of the body 111 defines a first end of a passage 112, inside which a valve mechanism 114 is housed, allowing the gas trapped in the volume V to flow through the passage 112 or preventing it from flowing. The valve mechanism 114 comprises a pin 115 (or a poppet valve) mounted so as to be able to move substantially along the axis X. 110 It translates between an open position, in which the pin 115 deflects from the seat and allows the gas trapped in the volume V to flow through the passage 112, and a closed position, in which the pin 114 bears against the seat and blocks the flow of said gas through said passage 112. A spring 116 returns the pin 115 towards its closed position, and a safety vent is provided at the thread of the first section 111.1, which opens into the valve mechanism 114, so as to allow the gas to escape from the volume V when the operator unscrews the valve 110, while the gas is still under pressure. As the valve mechanism 114 is well known in the prior art, it will not be described in further detail herein.

[0041] The second section 111.2 of the body 111 is provided on the outside with a second annular groove arranged at its free end. The second groove receives a second annular seal 117 intended to provide a tight seal between the second section 111.2 of the body 111 and the sensor support 120.

[0042] The second section 111 . 2 delimits a second end of the channel 112 , a portion of the inner side of the channel 112 being threaded, into which the fastening rod 130 is screwed.

[0043] The flange 111.3 is along the axis X 110 It has a substantially hexagonal cross section and comprises two cylindrical holes 118, the axes of which are parallel to the axis X. 110 , and appear on a second lateral face of the flange 111.3 facing the sensor support 120. The holes 118 are identical and are oriented relative to the axis X. 110 Each hole 118 receives an anti-rotation stud 119 protruding from the flange 111.3. In this example, each stud 119 is identical and has a diameter slightly larger than the diameter of the hole 118, which means that the stud 119 is press-fitted into the hole 118.

[0044] The sensor support 120 includes a main body portion 121 which is substantially tubular and extends along an axis X. 110 Basically coincident axis X 120 The main body portion 121 defines a passage 122 having a first end and a second end, the first end comprising a first hole 123 shaped to receive the second section 111.2 of the valve body 111, and a second end opposite the first end comprising a second hole 124 shaped to receive a portion of a fastening rod 130. A central portion of the passage 122 provides fluid communication between the first hole 123 and the second hole 124, and comprises a thread into which a fastening rod 130 can be screwed so that the fastening rod 130 extends through the central portion and remains fastened to the sensor support 120 when unscrewed from the valve body 111 (preventing loss of the fastening rod 130).

[0045] The inner diameter of the first hole 123 is slightly larger than the outer diameter of the second section 111 . 2 of the valve body 111 so as to allow the sensor support 120 to be fitted onto the second section 111 . 2 , the second seal 117 is intended to provide a tight seal between the second section 111 . 2 and the first hole 123 .

[0046] The end of the main body portion 121 facing the flange 111 . 3 of the valve body 111 comprises an outer collar 125 having lateral face portions that form an abutment when the sensor support 120 is fitted onto the second section 111 . 2 of the valve body 111 .

[0047] refer to Figure 5 The collar 125 includes a plurality of identical holes 126 arranged to cooperate in pairs with the short posts 119 carried by the valve body 111. The holes 126 are cylindrical and have a shape parallel to the axis X. 120 The hole 126 is oriented about the axis X and appears on the lateral face of the collar 125 facing the flange 111.3 of the valve body 111. 110 The holes 126 are symmetrically distributed, close to the outer periphery of the collar 125, and have a diameter slightly larger than the diameter of the short column 119. The centers of the holes 126 are located on the same circle, the center of which is located on the axis X. 120 Thus, the studs 119 and the holes 126 form a means for indexing the sensor support 120 at a certain angle on the valve body 111, and for preventing the sensor support 20 from moving relative to the valve body 111 about the axis X. 110 It should be noted that the hole 126 enables the sensor support 120 to occupy a position around the axis X relative to the valve body 111. 110 Multiple possible angular positions.

[0048] The sensor support 120 is held fitted to the valve body 111 via a fastening rod 130 which is substantially cylindrical and extends along the axis X. 120 Basically coincident axis X 130 Extends all the way through the main body portion 121 of the sensor support body 120 .

[0049] The fastening rod 130 comprises:

[0050] a first end 131 , the outer side of which is provided with a thread arranged to cooperate with a thread of a central part of the passage 122 of the sensor support 120 and with a thread in the second section 111 . 2 of the valve body 111 ;

[0051] a second end 132 which projects from the main body portion 121; and

[0052] A middle portion 132 . 1 which is arranged in the vicinity of the second end 132 to close the second hole 124 of the sensor support 120 .

[0053] The first end 131 of the tightening rod 130 comprises a front portion 133 arranged to bear against one end of the pin 115 and to bring said pin 115 from the closed position to the open position when the tightening rod 130 is screwed into the valve body 111. The first end 131 of the tightening rod 130 also comprises a through hole located at a position passing through the axis X. 130 , and emerges on either side of the thread of the fastening rod 130, forming a channel 134 that provides fluid communication between the channel 112 of the valve body 111 and the channel 122 of the sensor support 120, thereby allowing the gas trapped in the volume V to pass through the valve body 111 and reach the first hole 123 of the sensor support 120. In this case, the channel 134 is straight and extends along a plane relative to the axis X. 130 The inclined axis extends.

[0054] The second end 132 of the fastening rod 130 is provided with a 130 The second end 132 is provided with a cavity 132.2 cooperating with a rotating tool and comprising a base 132.3 forming an abutment when the tightening rod 130 is screwed into the valve body 111. The base 132.3 separates the second end 132 from a cylindrical middle portion 132.1 received in the second hole 124 of the main portion 121 of the sensor support 120. The middle portion 132.1 is provided with an annular groove on the outside, which receives an annular seal 135 intended to provide a tight seal between said middle portion 132.1 and the second hole 124 of the sensor support 120.

[0055] The sensor support 120 also includes a generally tubular secondary body portion 127 extending along a longitudinal axis relative to the axis X. 120 Inclined axis X 120’ protrudes from the main body portion 121. The secondary main body portion 127 defines a passage 128 having a first end opening to the outside of the sensor support 120 and a second end opposite to the first end, the second end opening into the passage 122 of the main body portion 121 between the seal 117 and the base of the first hole 123 of the main body portion 121. The passage 128 is stepped and thus comprises three consecutive holes 128.1, 128.2, 128.3 forming a housing in which the pressure sensor 140 is fitted: a first hole 128.1 opening to the outside of the sensor support 120, a second hole 128.2 opening to the first hole 128.1 and having a diameter greater than the diameter of the first hole 128.1, and a third hole 128.3 opening to the second hole 128.2 and having a diameter greater than the diameter of the second hole 128.2.

[0056] The pressure sensor 140 is substantially cylindrical and extends at the end of the cable 143 protruding from the cap 20. The pressure sensor 140 is fixed in a sealing manner in the secondary body part 127 of the sensor support 120 by means of a locking ring 150 and a seal 144 carried by said pressure sensor 140. The locking ring 150 is screwed onto an external thread provided at the free end of the secondary body part 127 of the sensor support 120 and comprises an internal shoulder 151 arranged to cooperate with a first external shoulder 141 of the pressure sensor 140 so that a second external shoulder 142 of said pressure sensor 140 abuts against said free end of the secondary body part 127. The seal 144 provides a tight seal between the pressure sensor 140 and the second hole 128.2 of the secondary body part 127 of the sensor support 120.

[0057] The pressure sensor 140 is of the piezoelectric type in this case and comprises a pressure probe 145 designed to measure pressures within the useful range of tire internal pressures. The pressure probe 145 is connected via a cable 143 to a module 146 for processing the signals and controlling the pressure probe 145. The module 146 comprises a printed circuit arranged on the base 21 of the cap 20, surrounding the bushing 24.

[0058] The processing unit 147 is fixed to a fixed part of the landing gear or to the fuselage of the aircraft and is able to use, in particular display, the pressure measurements made using the pressure sensor 140. The module 146 and the processing unit 147 are connected to each other by communication means (not shown) suitable for establishing radio frequency transmission, i.e. transmission by Hertz means, between said module 146 and said processing unit 147. This transmission is bidirectional, i.e. each entity can send and receive information. The communication means are also able to transmit, by Hertz means, the electrical energy required for the operation of the pressure sensor 140.

[0059] Thus, the sensor support 120, the sensor 140 and the locking ring 150 form an assembly that can be removed from the valve 110 simply by unscrewing and withdrawing the tightening rod 130. Unscrewing the tightening rod 130 causes the pin 115 of the valve 110 to be displaced from the open position to the closed position (before the thread of the tightening rod 130 is completely disengaged from the threaded hole), thus allowing the assembly formed by the sensor support 120, the sensor 140 and the locking ring 150 to be disassembled without this removal causing deflation of the tire 2. There is then no need to unscrew the locking ring 150 during maintenance operations.

[0060] The stud 119 carried by the valve 110 and the hole 126 provided in the sensor support 120 make it possible to:

[0061] - Positioning the sensor support 120 (and thus the sensor 140) along the axis X 100The aperture 126 is angled relative to the valve 110 to provide several possible angular positions; and

[0062] - constraining the valve 110 and the sensor support 120 to rotate so that the valve support 120 (and therefore the sensor 140 ) is prevented from rotating relative to the valve 110 about the axis X 100 , X 120 Rotate.

[0063] The use of a safety wire safety device and determination of the tightening torque of the tightening rod 130 and the locking ring 150 allow for better control and reproducibility of the assembly of the device 100 .

[0064] Of course, the invention is not limited to the embodiments described but covers any variant coming within the ambit of the invention as defined by the claims.

[0065] Although in this example the device 100 is applied to wheels R provided with a main landing gear P, it may also be applied to wheels provided with a main landing gear P. Figure 1 The wheel of the front landing gear of the aircraft A is shown, but more generally it can also be applied to any wheel equipped with a landing gear.

[0066] Although the apparatus 100 is applied to an aircraft wheel in this example, it may more generally be applied to any vehicle equipped with a wheel having tire entrapment.

[0067] There may be more than two short columns 119. Preferably, the short columns 119 are arranged around the axis X. 110 Evenly distributed.

[0068] The stud 119 and the hole 126 may be replaced by any other angular indexing means that allows the sensor support 120 to be positioned at a certain angle relative to the valve 110. For example, Figure 7 As shown, the second section 111 . 2 of the valve body 111 may include an external toothed ring 119 ′ which is designed to cooperate with an internal toothed ring received in the first bore 123 of the sensor support 120 .

[0069] Although the sub-body portion 127 of the sensor support 120 extends obliquely relative to the main body portion 121 of the sensor support in this example, it may also extend in a vertical direction. Regardless of whether the sub-body portion 127 extends in an oblique direction or a vertical direction relative to the main body portion 121, in this case, the sub-body portion 128 is considered to be oblique relative to the main body portion 121.

Claims

1. A device (100) for measuring the gas pressure contained in a tire (2) mounted on a rim (1) of a wheel (R), the device comprising: - a valve (110) adapted to be mounted on the rim (1), comprising a first gas flow channel (112), a pin (115) mounted so as to be able to translate in the first channel between a position in which the first channel is open and a position in which the first channel is closed, and a spring (116) for returning the pin to the closed position; an intermediate body (120) mounted on the valve and defining 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, a second end and a middle portion, the first end protruding into the first channel for moving the pin from the closed position to the open position, the second end being accessible from outside the second channel, the middle portion closing the second channel; a pressure sensor (140) received in a third channel (128) of the intermediate body, the third channel opening into the second channel between the first end and the intermediate portion of the fastening rod, inclined relative to the second channel; as well as - means (150) for retaining said pressure sensor in said third channel of said intermediate body.

2. The device (100) according to claim 1, characterized in that Means (119, 126) are included for indexing the intermediate body (120) at a certain angle relative to the valve (110).

3. The device (100) according to claim 2, characterized in that 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, characterized in that The stud (119) and the hole (126) are arranged to provide at least two possible angular positions of the intermediate body (120) relative to the valve (110).

5. The device (100) according to any one of the preceding claims, characterized in that The first end of the fastening rod (130) includes a through hole forming a fourth air flow channel (134).

6. The device (100) according to any one of the preceding claims, characterized in that The first end of the fastening rod (130) includes threads that engage in the threaded hole of the first passage (112).

7. The device (100) according to any one of the preceding claims, characterized in that The retaining means comprises a locking ring (150) arranged to be fastened to the intermediate body (127) to retain the pressure sensor (140) in the third passage (128).

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

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

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

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