NUT BRAKING SYSTEM FOR AN AIRCRAFT TURBOMACHINE
The nut braking system in aircraft turbomachines achieves precise locking through annular parts and brake washers with complementary teeth and grooves, addressing imprecision and torque issues in existing systems.
Patent Information
- Application Number
- FR2023010868
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-10-11
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2043-10-11
AI Technical Summary
Existing nut braking systems in aircraft turbomachines suffer from imprecision in locking mechanisms, leading to potential axial play and excessive torque, which can affect the load on components like guide bearings.
A nut braking system comprising annular parts with notches and brake washers with alternating teeth and grooves, allowing precise adjustment without excess torque, using complementary radial orientations and a stop ring for secure locking.
Ensures precise nut locking with minimal axial play and reduced torque, enhancing the stability of components like rolling bearings without the need for specialized tools.
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Abstract
Description
Title of the invention: NUT BRAKING SYSTEM FOR AN AIRCRAFT TURBOMACHINE Technical field of the invention
[0001] The present invention relates to a nut braking system for an aircraft turbomachine. Technological background
[0002] Conventionally, with reference to [Fig.l], in a turbomachine such as a turbojet or a turboprop, a shaft 1 such as the shaft 1 of a low-pressure compressor comprises an upstream cylindrical end portion 2, in the direction of flow of the gases in the turbomachine, which is engaged coaxially in a cylindrical portion 3 of a disk 4 such as a fan disk. The cylindrical portion 3 of the disk 4 comprises internal splines 5 engaged in complementary splines 6 of the shaft 1 to make the shaft 1 and the disk 4 integral in rotation. The cylindrical portion 2 of the shaft comprises, in the vicinity of its upstream end, an external thread 7 for screwing a nut 8 with internal thread.
[0003] This nut 8 is screwed from upstream onto the cylindrical part 2 of the shaft and comprises at its downstream end axial support means 9 on the disc 4 to tighten it axially between the nut 8 and an axial stop 10 of the compressor shaft 1. Means for braking the nut 8 with respect to the shaft 1 are provided to prevent the nut from loosening during operation.
[0004] These braking means are for example teeth 11 which extend axially from the upstream end of the nut 8 towards the upstream and which are regularly spaced from each other around the axis of the shaft 1 so as to define notches between each tooth 11. The shaft 1 also comprises similar teeth 12 so that the teeth 12 of the shaft 1 and the teeth 11 of the nut 8 are radially opposite each other to allow the mounting of a ring 13 for braking the nut 8. This ring 13 comprises at least one radially external tab 14 engaged in a notch defined by two of the teeth 11 of the nut 8, and at least one radially internal tab 15 engaged in a notch defined by two of the teeth 12 of the shaft 1. The tabs 14, 15 cooperate by abutment in the direction circumferential with the teeth 11, 12, arranged on either side of these lugs, to lock the nut 8 in rotation with respect to the shaft 1.
[0005] The teeth 11 of the nut comprise an internal annular groove for housing a split annular retaining ring 16. This ring 16 bears axially on the ring 13 and prevents it from disengaging from the nut 8 and the shaft 1.
[0006] In the example presented above, the nut makes it possible to axially lock the fan disc. In other configurations, a similar fixing device can make it possible to axially lock other annular parts such as a guide bearing. This aspect is developed in particular in documents FR-B1-2 857 708, FR-B1-2 929 358, FR-B1-3 013 388 or FR-B1-3 093 538.
[0007] In practice, it has been found that the precision of the braking of a nut has an impact on the load undergone by the part, in particular a guide bearing such as a rolling bearing, blocked axially.
[0008] Also, an objective of the present invention is to provide an improved nut braking system solution. Summary of the invention
[0009] A nut braking system is therefore proposed for an aircraft turbomachine, comprising: - an annular part which extends around an axis and which has a thread around this axis as well as at least one first notch oriented radially relative to the axis, - a nut which extends around the axis and which is capable of being screwed onto the thread, this nut defining around the part an annular housing and comprising at least a second notch oriented radially relative to the axis, - a first brake washer which extends around the axis and which is capable of being housed in the annular housing, this first brake washer comprising at least one first finger oriented radially with respect to the axis and capable of being housed respectively in the at least one first notch in order to secure in rotation the first washer with the annular part, the first brake washer comprising two radial bearing faces, a first face of which comprises an alternation of teeth and grooves around the axis, the teeth and grooves of the first washer having a radial orientation with respect to the axis, - a second annular brake washer which extends around the axis and which is capable of being housed in the annular housing, this second brake washer comprising at least one second finger oriented radially with respect to the axis and capable of being housed respectively in the at least one second notch in order to secure in rotation the second washer with the nut, the second brake washer comprising two radial bearing faces, a first face of which is capable of coming to bear against the first face of the first washer and comprises an alternation of teeth and grooves around the axis, the teeth and grooves of the second washer having a radial orientation with respect to the axis and being complementary to the teeth and grooves of the first washer, one of the first and second washers having a second face which is axially supported on the nut, and - a stop ring which extends around the axis and which is capable of being housed in the annular housing as well as in an annular groove of the nut, the stop ring being axially supported on a second face of the other of the first and second washers.
[0010] Thus, thanks to the nut braking system according to the invention, a more precise adjustment of the braking of a nut is ensured without generating excess torque and without the need for specific tools. Indeed, the teeth and grooves present on the first faces of the brake washers, once in contact, make it possible to limit a potential axial play between these two washers.
[0011] The nut locking system according to the invention may comprise one or more of the following features, taken in isolation from each other or in combination with each other: - the housing is defined between a free end of the nut and a free end of the part; - the teeth, or grooves, of each brake washer have a pitch between each of the teeth, or each of the grooves, less than or equal to 5 degrees, preferably less than or equal to 2 degrees, more preferably less than or equal to 1 degree, and even more preferably less than or equal to 0.5 degrees; - each of the brake washers comprises at least two or three fingers distributed around the axis; - the teeth and grooves extend over the entire radial extent of each of the brake washers; - the teeth and grooves extend over the fingers of each of the brake washers; - the thread of the annular part is an external thread; - the second brake washer has the second bearing face on the nut, and the first brake washer has the second bearing face on the stop ring; - the system comprises a rolling bearing which extends around the axis, the rolling bearing being mounted on the annular part, the rolling bearing being clamped axially between an annular shoulder of the part and the nut, the nut bearing axially on the rolling bearing; - the thread has a pitch of less than 5 mm, preferably less than 3 mm, more preferably less than 2 mm, and even more preferably less than or equal to 1.5 mm; - the at least one first notch of the annular part is capable of being ra- directly aligned with the at least one second notch of the nut when the nut is in the tightened position; - the teeth and grooves of each brake washer have a thickness less than or equal to 0.2 millimeters; - the thread has an average diameter greater than or equal to 40 millimeters.
[0012] The invention also relates to an aircraft turbomachine comprising at least one nut braking system as described above. Brief description of the figures
[0013] The invention will be better understood and other characteristics and advantages will become apparent with the aid of the detailed description which follows, comprising embodiments given solely for illustrative purposes with reference to the appended figures, which may serve to complete the understanding of the present invention and the description of its embodiment and, where appropriate, contribute to its definition, in which:
[0014] [Fig.l] represents a schematic half-view in axial section of a device for fixing an annular part on a shaft of a turbomachine, according to the prior art;
[0015] [Fig.2] represents a schematic perspective view of a braking system nut according to the invention;
[0016] [Fig.3] represents a schematic view along an axial sectional plane of the nut braking system of [Fig.2];
[0017] [Fig.4] represents a schematic view of an enlarged area of [Fig.3];
[0018] [Fig. 5] represents a schematic perspective view along a section plane axial of an enlarged area of [Fig.2];
[0019] [Fig.6] represents a very schematic view along a transverse section plane AA of the brake washers, according to the invention. Detailed description of the invention
[0020] With reference to [Fig.2] to 5, the nut braking system 100 for an aircraft turbomachine, according to the invention, comprises an annular part 110, a nut 120, a first brake washer 130, a second brake washer 140 and a stop ring 150.
[0021] The annular part 110 extends around an axis X and comprises a thread 112 around this axis X. The part 110 also comprises at least one first notch 111 oriented radially relative to the axis X.
[0022] The nut 120 extends around the axis X and is adapted to be screwed onto the thread 112 of the part 110. The nut 120 further defines around the part 110 an annular housing 122. Advantageously, this housing 122 is defined between a free end of the nut 120 and a free end of the part 110. The nut 120 also comprises at least less a second notch 121 oriented radially relative to the X axis.
[0023] The first brake washer 130 extends around the axis X and is able to be housed in the annular housing 122. The first brake washer 130 comprises at least one first finger 131 which is oriented radially relative to the axis X. This first finger 131 is also able to be housed respectively in the at least one first notch 111, in order to secure in rotation the first brake washer 130 with the annular part 110. It is understood that there are at least as many first notches 111 on the part 110 as there are first fingers 131 on the first brake washer 130, but not vice versa. Indeed, there may be fewer first fingers 131 than first notch 111.
[0024] The first brake washer 130 further comprises two radial support faces 132a, 132b, i.e. a first face 132a and a second face 132b. The first face 132a of the first brake washer 130 comprises an alternation of teeth 133 and grooves 134, visible in [Fig. 6] and detailed later. This alternation of teeth 133 and grooves 134 of the first face 132a of the first brake washer 130 extends around the axis X and has a radial orientation with respect to the axis X.
[0025] The second brake washer 140 extends around the axis X and is able to be housed in the annular housing 122. The second brake washer 140 comprises at least one second finger 141 which is oriented radially relative to the axis X. This second finger 141 is also able to be housed respectively in the at least one second notch 121 of the nut 120, in order to secure in rotation the second brake washer 140 with the nut 120. It is understood that there are at least as many second notches 121 on the nut as there are second fingers 141 on the second brake washer 140, but not vice versa. Indeed, there may be fewer second fingers 141 than second notch 121.
[0026] The second brake washer 140 further comprises two radial bearing faces 142a, 142b, i.e. a first face 142a and a second face 142b. The first face 142a of the second brake washer 140 is capable of bearing against the first face 132a of the first washer 130. It is understood that the bearing in question is axial. The first face 142a of the second brake washer 140 comprises an alternation of teeth 143 and grooves 144, visible in [Fig. 6] and detailed later. This alternation of teeth 143 and grooves 144 of the first face 142a of the second brake washer 140 extends around the axis X and has a radial orientation with respect to the axis X.
[0027] The teeth 143 and the grooves 144 of the first face 142a of the second brake washer 140 are complementary to the teeth 133 and the grooves 134 of the first face 132a of the first brake washer 130.
[0028] One of the first and second brake washers 130, 140 has a second face 132b, 142b which is in axial support on the nut 120. In other words, the first brake washer 130 has a second face 132b which can be in axial support on the nut 120 or the second brake washer 140 has a second face 142b which can be in axial support on the nut 120. In the embodiment presented in FIGS. 2 to 5, it is the second face 142b of the second brake washer 140 which is in axial support on the nut 120.
[0029] The stop ring 150 extends around the axis X and is able to be housed in the annular housing 122. The stop ring 150 is furthermore housed in an annular groove 124 of the nut 120. The stop ring 150 is configured to bear axially on a second face 132b, 142b of the other of the first and second washers 130, 140. In the embodiment of FIGS. 2 to 5, the stop ring 150 comprises a first face 152a which bears axially on the second face 132b of the first brake washer 130.
[0030] Advantageously, the stop ring 150 is retained axially on the one hand by one of the brake washers 130, 140 and on the other hand by an annular rim 126 of the groove 124, in particular a second face 152b of the stop ring 150 bears on this rim 126.
[0031] Advantageously, each of the brake washers 130, 140 comprises at least two or three fingers 131, 141 distributed around the axis X. In other words, the first brake washer 130 may comprise at least two or three first fingers 131 while the second brake washer 140 may comprise at least two or three second fingers 141. Preferably, a first finger 131 of the first brake washer 130 bears axially on a second finger 141 of the second brake washer 140.
[0032] Advantageously, the at least one first notch 111 of the annular part 110 is capable of being radially aligned with the at least one second notch 121 of the nut 120, when the nut 120 is in the tightened position.
[0033] With reference to [Fig. 6], which represents a very schematic and simplified view of the brake washers 130, 140, according to the transverse section plane AA indicated in [Fig. 4], the teeth 133, 143, or the grooves 134, 144, of one of the brake washers 130, 140 are able to cooperate with the grooves 134, 144, or the teeth 133, 143, of the other of the brake washers 130, 140. In other words, in the example given, the teeth 133 of the first brake washer 130 cooperate with the grooves 144 of the second brake washer 140, the teeth 133 and the grooves 144 are complementary. The grooves 134 of the first brake washer 130 cooperate with the teeth 143 of the second brake washer 140, the grooves 134 and the teeth 143 are complementary.
[0034] Advantageously, the teeth 133, 143 and the grooves 134, 144 extend over the entire radial extent of each of the brake washers 130, 140. In this way, a braking of the first and second brake washers 130, 140 relative to each other. This braking of the washers 130, 140 relative to each other can be further improved when the teeth 133, 143 and the grooves 134, 144 extend over the fingers 131, 141 of each of the brake washers 130, 140, and each first finger 131 is axially supported on each second finger 141, or vice versa.
[0035] Advantageously, the teeth 133, 143, or the grooves 134, 144, of each brake washer 130, 140 have a pitch between each of the teeth 133, 143, or the grooves 134, 144, less than or equal to 5 degrees, preferably less than or equal to 2 degrees, more preferably less than or equal to 1 degree, and even more preferably less than or equal to 0.5 degrees.
[0036] The teeth 133, 143 and the grooves 134, 144 of each brake washer 130, 140 may have a thickness less than or equal to 0.2 mm. Thickness is understood to mean the distance separating a top of a given tooth 133, 143 and a fictitious point projected perpendicular to the top from a hollow of a groove 134, 144, this groove 134, 144 being located in the immediate vicinity of the given tooth 133, 143.
[0037] The thread 112 of the annular part 110 may be an external thread as shown in FIGS. 2 to 5.
[0038] In a variant, not shown, the thread 112 of the part 110 is an internal thread. In such a case, it is understood that the nut 120, having a corresponding external thread, the brake washers 130, 140 and the stop ring 150 are mounted inside the part 110.
[0039] The thread 112 of the nut 120 may have a pitch of less than 5 mm, preferably less than 3 mm, more preferably less than 2 mm, and even more preferably less than or equal to 1.5 mm.
[0040] The thread 112 may have an average diameter greater than or equal to 40 mm.
[0041] As shown in Figures 2 to 5, the nut braking system 100 according to the invention may comprise a rolling bearing 160 which extends around the axis X. This rolling bearing 160 is mounted on the annular part 110. The rolling bearing 160 is then clamped axially between an annular shoulder 114 of the part 110 and the nut 120. It is understood that the nut 120 bears axially on the rolling bearing 160, which comprises an inner ring 161 and an outer ring 162, in particular on an inner ring 161 of the rolling bearing 160.
[0042] The rolling bearing 160 may be an angular contact rolling bearing.
[0043] The invention also relates to an aircraft turbomachine comprising at least one nut braking system 100 as described previously.
[0044] The nut braking system according to the invention and as described above, makes it possible to ensure more precise adjustment of the braking of a nut without generating excess torque and without the need for specific tools. Indeed, the teeth and grooves present on the first faces of the brake washers, once in contact, make it possible to limit potential axial play between the two brake washers. In particular, this makes it possible to manage braking of less than 0.008 mm, preferably less than 0.005 mm, and even more preferably less than 0.002 mm.
[0045] The invention is particularly advantageous with a rolling bearing because it makes it possible not to overload the bearings and makes it possible not to unload them.
Claims
1. Claims Nut braking system (100) for an aircraft turbomachine, comprising: - an annular part (110) which extends around an axis (X) and which comprises a thread (112) around this axis as well as at least one first notch (111) oriented radially relative to said axis, - a nut (120) which extends around said axis (X) and which is capable of being screwed onto said thread (112), said nut defining around said part an annular housing (122) and comprising at least one second notch (121) oriented radially relative to said axis, - a first brake washer (130) which extends around said axis (X) and which is capable of being housed in said annular housing (122), said first brake washer comprising at least one first finger (131) oriented radially with respect to said axis (X) and capable of being housed respectively in said at least one first notch (111) in order to secure in rotation the first brake washer (130) with the annular part (110), said first brake washer (130) comprising two radial bearing faces (132a, 132b) of which a first face (132a) comprises an alternation of teeth (133) and grooves (134) around said axis (X), said teeth (133) and said grooves (134) of the first brake washer (130) having a radial orientation with respect to said axis (X), - a second brake washer (140) which extends around said axis (X) and which is capable of being housed in said annular housing (122), said second brake washer (140) comprising at least one second finger (141) oriented radially relative to said axis (X) and capable of being housed respectively in said at least one second notch (121) in order to secure in rotation the second brake washer (140) with the nut (120), said second brake washer comprising two radial bearing faces (142a, 142b) of which a first face (142a) is capable of coming to bear against the first face (132a) of the first washer (130) and comprises an alternation of teeth (143) and grooves (144) around said axis, said teeth (143) and said grooves (144) of the second brake washer (140) having a radial orientation with respect to said axis (X) and being complementary to said teeth (133) and said grooves (134) of the first washer (130), one of said first and second washers (130, 140) having a second face (132b, 142b) which is axially supported on the nut (120), and - a stop ring (150) which extends around said axis (X) and which is capable of being housed in said annular housing (122) as well as in an annular groove (124) of the nut (120), said stop ring (150) being axially supported on a second face (132b, 142b) of the other of said first and second washers (130, 140).
2. A nut locking system (100) according to claim 1, wherein said housing (122) is defined between a free end of said nut (120) and a free end of said part (110).
3. A nut locking system (100) according to any one of claims 1 or 2, wherein said teeth (133, 143), or said grooves (134, 144), of each brake washer (130, 140) have a pitch (PI, P2) between each of said teeth (133, 143), or said grooves (134, 144), less than or equal to 5 degrees, preferably less than or equal to 2 degrees, more preferably less than or equal to 1 degree, and even more preferably less than or equal to 0.5 degrees.
4. A nut locking system (100) according to any one of claims 1 to 3, wherein each of said locking washers (130, 140) comprises at least two or three fingers (131, 141) distributed around said axis (X).
5. A nut locking system (100) according to any one of claims 1 to 4, wherein said teeth (133, 143) and said grooves (134, 144) extend over the entire radial extent of each of the lock washers (130, 140).
6. A nut locking system (100) according to any one of claims 1 to 5, wherein said teeth (133, 143) and said grooves (134, 144) extend over the fingers (131, 141) of each of the lock washers (130, 140).
7. A nut locking system (100) according to any one of claims 1 to 6, wherein said thread (112) of said part (110) is an external thread.
8. A nut locking system (100) according to any one of claims 1 to 7, wherein said second lock washer (140) has the second face (142b) bearing on said nut (120), and said first lock washer (130) has the second face (132b) bearing on said retaining ring (150).
9. Nut braking system (100) according to any one of claims 1 to 8, comprising a rolling bearing (160) which extends around said axis (X), said rolling bearing being mounted on said part (110), said rolling bearing being axially clamped between an annular shoulder (114) of said part and said nut (120), said nut bearing axially on said rolling bearing (160).
10. A nut locking system (100) according to any one of claims 1 to 9, wherein said thread (112) has a pitch of less than 5 millimeters, preferably less than 3 millimeters, more preferably less than 2 millimeters, and even more preferably less than or equal to 1.5 millimeters.
11. A nut locking system (100) according to any one of claims 1 to 10, wherein said at least one first notch (111) of said annular part (110) is adapted to be radially aligned with said at least one second notch (121) of said nut (120) when the nut is in the tightened position.
12. A nut locking system (100) according to any one of claims 1 to 11, wherein said teeth (133, 143) and said grooves (134, 144) of each lock washer (130, 140) have a thickness less than or equal to 0.2 millimeters.
13. A nut locking system (100) according to any one of claims 1 to 12, wherein said thread (112) has an average diameter greater than or equal to 40 millimeters.
14. Aircraft turbomachine comprising at least one nut braking system (100) according to any one of claims 1 to 13.