Protective device for bearing defects in rotary electric machine

Abstract

The invention relates to a rotary machine comprising coaxial rotor (20) and stator (30), the rotor (20) being free to rotate about an axis of rotation X, the machine comprising a bearing (10) for guiding the rotation of the rotor (20), the bearing (10) being in contact with a surface (200) of the rotor (20), the bearing (10) comprising a roller bearing arrangement (100) around the rotor (20) and a detection arrangement (110), the detection arrangement (110) comprising a first element (110 ') and a second element (110' '), the first element (110 ') extends around the rotor (20) and the second element (110' ') is rigidly connected to the stator (30), the detection device (110) being configured to switch from a stationary configuration in which the first element (110') is remote from the rotor (20) and the second element (110 '') to a braking configuration in which the first element (110 ') is rotated by the rotor (20) and in which the second element (110' ') exerts a force on the first element (110') opposite to the rotation, the detection device (110) is configured to switch from the stationary configuration to the braking configuration when the rotation of the rotor (20) is eccentric with respect to the rotation axis X.

Description

Technical Field

[0001] This invention relates to the field of aviation, and more particularly to rotating electric machines of the type of electric motor or generator that allow the conversion of electrical energy into mechanical energy and vice versa, for use in equipping transportation vehicles, such as aircraft, like airplanes or helicopters. However, the invention is not limited to the transportation field and is applicable to any segmented rotating electric system. More specifically, this invention relates to a device for preventing rotational coaxiality defects in the rotor of a rotating electric machine. Background Technology

[0002] The application fields of this invention relate to generators and power supply motors associated with their converters, including: - A synchronous or asynchronous motor, but not limited to this, having: - For the stator, there is a main winding, which, as a non-limiting example, can be multiphase; - For the rotor, there are squirrel-cage or equivalent mounted magnets, which are located on the surface or embedded and do not have a preset magnetization type or magnet type; - Rotary bearings or rotational guide assemblies for rotors, including, for example, roller bearings, to ensure rotor rotation; - A shaft that allows the motor to be connected to a downstream housing, such as a gearbox, via a spline.

[0003] Unfortunately, certain events can cause generator and / or motor components to fail; this specifically involves the following types of events: - Lubrication failure in either the bearing or the rotating guide. This type of defect can cause the roller bearing assembly to overheat and there is a risk of the high temperature spreading until the bearing malfunctions and reaches its auto-ignition point; or - Slow or sudden failure of one or more bearings. This type of defect can cause the rotor to lose support relative to the stator, generating unwanted heat near the air gap and posing a risk of high-temperature propagation.

[0004] These two events typically cause rotor eccentricity relative to the stator and component overheating, leading to failure of one component or even the entire machine. In such cases, it is necessary to stop the rotor's rotation to minimize any damage and prevent any unintended cracking or failure of the rotating motor or to prevent a fire.

[0005] To avoid these worrying incidents, different types of devices are known to be used: - A mechanically fused or "fractured" type slider located on the axis of a rotating machine. The advantage of this type of device is its relative simplicity and small size. The main disadvantage is that disengagement can only be achieved if the rotor torque is sufficiently high. More specifically, the fractured part acts as a fuse with a predetermined mechanical strength. Therefore, a sufficiently large force or torque needs to be applied to this fuse to yield. However, low-strength mechanical fuses can break even when the shaft is intact and no alarming events have occurred. However, such breakage can only occur if there is sufficient mechanical resistance to brake the rotor. Furthermore, in the case of bearing lubrication loss, the rotating machine may be observed to crack or overheat without generating sufficient and significant braking torque to damage the drive shaft; - A dynamic disengagement device, consisting of actuators for connecting two shafts—that is, the shaft connecting the rotating electric motor and the shaft of the drive system. This device includes controlled disengagement mechanisms. Therefore, when an operational defect is detected, these mechanisms are actuated to disengage the shaft as it rotates. Such a dynamic device may be a viable solution; however, it has several major drawbacks. The space required to install this type of device and its mass are inconsistent with the space typically available for integrating rotating electric motors. Furthermore, disengagement can only be performed upon command, which itself is based on an algorithm or detection when a threshold is exceeded. Therefore, the reliability of the dynamic device is closely related to the reliability of the detection system, algorithm, and control electronics. Thus, adding such a dynamic device significantly degrades the reliability of the rotating electric motor. Summary of the Invention

[0006] The present invention aims to overcome all or part of the aforementioned problems by proposing a passive and compact detection and disengagement device. This detection device allows for the detection of any eccentricity in the rotation of a shaft and immediate action upon detection of a defect in the shaft's rotation.

[0007] Therefore, the present invention relates to a rotating machine comprising a coaxial rotor and a stator, the rotor being configured to rotate freely about a rotation axis X, the rotating machine including at least one bearing configured to guide the rotation of the rotor, the at least one bearing being in contact with a surface of the rotor. The bearing includes a roller bearing assembly extending concentrically around the rotor and a detection device for detecting rotational defects. The detection device for detecting rotational defects includes a first element and a second element, the first element extending concentrically around the rotor, and the second element being rigidly connected to the stator. The detection device is configured to switch from a static configuration to a braking configuration, in which the first element is located away from the rotor and the second element, and in the braking configuration, the first element is configured to be rotated by the rotor and the second element applies a force on the first element opposite to the rotation of the rotor. The detection device is configured to switch from the stationary configuration to the braking configuration when the rotation of the rotor is eccentric relative to the rotation axis X.

[0008] According to one aspect of the invention, the first element is juxtaposed with the roller bearing assembly along the rotation axis X.

[0009] According to one aspect of the invention, the roller bearing assembly is located at a first predetermined distance from the surface of the rotor, wherein the first element is located at a second distance from the surface of the rotor, the second distance being defined according to the following formula: Where D2 represents the second distance between the surface separating the rotor and the first element, D1 represents the first distance between the surface separating the rotor and the roller bearing assembly, and x represents a predefined eccentricity detection ratio.

[0010] According to one aspect of the invention, the first element includes a protrusion, and wherein the second element includes a stop that contacts the protrusion in the braking configuration and is away from the protrusion in the stationary configuration.

[0011] According to one aspect of the invention, the protrusion is defined relative to the rotor along a radial axis R. Attached Figure Description

[0012] The invention will be better understood and other advantages will become apparent from reading the embodiments provided by way of example and from the detailed description illustrated in the accompanying drawings, wherein: [ Figure 1 ] Figure 1 A front view of an assembled model of the bearings of a rotating machine according to the present invention is shown; [ Figure 2 ] Figure 2 It shows Figure 1 A side view of an assembly model of the bearings of a rotating machine according to the present invention; [ Figure 3 ] Figure 3 It shows Figure 1 A schematic diagram of the first element of a device for detecting rotational defects; [ Figure 4 ] Figure 4 It shows Figure 1A schematic diagram of the second element of a device for detecting rotational defects. Detailed Implementation

[0013] For clarity, the same elements in each figure use the same reference numerals.

[0014] Figure 1 A front view of a bearing 10 of a rotating machine is shown. The rotating machine includes a coaxial rotor 20 and a stator 30. Therefore, the rotor 20 is configured to rotate freely about a rotation axis X. The rotor 20 rotates freely within the stator 30, which is fixed relative to the rotor 20. The rotating machine also includes at least one bearing 10 configured to guide the rotation of the rotor 20, aligning it with respect to the rotation axis X. The rotor 20 of the rotating machine passes through at least one bearing 10 along a passage section 101, as shown. Figure 1 As shown.

[0015] In other words, at least one bearing 10 maintains the rotation of the rotor 20 relative to the axis of rotation X. At least one bearing 10 is in contact with the surface 200 of the rotor 20.

[0016] At least one bearing 10 may be in intermittent contact with the surface 200 of the rotor 20. Preferably, at least one bearing 10 is in permanent contact with the surface 200. In other words, at least one bearing 10 is connected to the concentric surface 200.

[0017] For this purpose, at least one bearing 10 includes, for example, a roller bearing assembly 100 extending concentrically around the rotor 20. The roller bearing assembly 100 is in direct contact with the surface 200 of the rotor 20. Therefore, the roller bearing assembly 100 allows the rotor 20 to rotate freely relative to the at least one bearing 10. As an indicative example, the roller bearing assembly 100 can be any type of roller bearing that ensures the rotational movement of the rotor 20 relative to the at least one stationary bearing 10. Preferably, the roller bearing assembly 100 is a ball bearing.

[0018] At least one bearing 10 also includes a device 110 for detecting rotational defects in the rotor 20. The detection device 110 is configured to switch from a stationary configuration to a braking configuration for braking the rotor 20 if at least one bearing is no longer guided and causes revolution, i.e., its rotation is no longer perfectly concentric and comes into frictional contact with surrounding elements. The detection device 110 serves as a freewheel type mechanism that is not directly rotated and is mounted with a certain gap relative to the rotor 20.

[0019] The detection device 110 for detecting rotational defects includes a first torque amplifier element 110' and a second element 110" for detecting the eccentricity of the rotation of the rotor 20. The first element 110', or the torque amplifier of the rotor 20, is an element that extends concentrically around the rotor 20 in a manner similar to the roller bearing assembly 100.

[0020] In the static configuration of the rotating defect detector 110, the first element 110' or the torque amplifier of the rotor is a free element, that is, it rotates freely relative to the rotor 20, but is not necessarily driven to rotate by the rotor 20. In other words, the first element 110' or the torque amplifier of the rotor 20 idles relative to the rotor 20 and relative to the stator 30, and there is a gap or distance between the rotor 20 and the first element 110'.

[0021] The second element 110" or the detector for detecting the rotational eccentricity of the rotor 20 is an element rigidly connected to the stator 30 and fixed relative to the rotor 20.

[0022] Furthermore, in the static configuration of the detector 110 used to detect rotational defects in the rotor 20, the first element 110' or the torque amplifier of the rotor 20 is located away from the rotor 20 and the second element 110". Therefore, the rotor is connected to at least one bearing 10 only via the roller bearing assembly 100, and the second element 110" is not connected to the first torque amplifier element 110' of the rotor 20. In other words, the first element 110' or the torque amplifier of the rotor 20 is disconnected from the rotor 20 and the second element 110".

[0023] Therefore, this static configuration of the rotating defect detector 110 represents the normal operation of the rotating machine and the rotor 20. More specifically, the static configuration establishes the fact that the rotation of the rotor 20 is substantially concentric and that the axis of rotation X of the rotor 20 cannot move while the rotor 20 is rotating.

[0024] In the braking configuration of the detection device 110, the torque amplifier of the first element 110' or rotor 20 is driven to rotate by the rotor 20. Any type of drive is conceivable, for example, using the magnetic force of the magnet between the rotor 20 and the first element 110'. Preferably, when the first element 110' is driven to rotate by the rotor 20, it is then mechanically connected to the rotor 20.

[0025] More specifically, this eccentricity can be detected on the first element 110' when the rotation of rotor 20 is no longer concentric, i.e., when the rotation axis X of rotor 20 can move in any way. In effect, the imperfect rotation of rotor 20 and the eccentricity of its rotation allow rotor 20 to contact the first torque amplifier element 110'. Then, due to the mechanical contact between the completed rotating rotor and the first element 110', the first torque amplifier element 110' is driven by rotor 20, thereby rotating in a manner similar to rotor 20.

[0026] Therefore, unlike the static configuration, in the braking configuration of the detection device 110, the rotor 20 and the first element 110' complete the rotation.

[0027] Therefore, once driven by rotor 20, the first element 110' allows for an increase in the rotational torque of rotor 20. In effect, the torque of rotor 20 is thus a combination of the torques of rotor 20 and the first element 110'. Furthermore, it is conceivable that the first element 110 is larger than rotor 20. More specifically, if the first element 110' takes a circular shape, such as... Figure 1 As shown, it can be envisioned that the cross-section or diameter of the first element 110' is larger than the diameter or cross-section of the rotor 20, so that when the rotor 20 drives the first element 110' to rotate, the rotation of the first element 110' significantly increases the rotational torque of the rotor 20.

[0028] As a variation, it is also conceivable that the first element is more compact or exhibits a density or mass density greater than that of the rotor 20, so as to increase the rotational torque of the rotor 20 when the rotor 20 drives the first element 110' to rotate.

[0029] In the braking configuration, the second element 110" also applies a force opposite to the rotation of the rotor 20 to the first element 110'. Therefore, the second element 110" functions as a brake relative to the first element 110' and relative to the rotor 20. As an indicative example, the second braking element 110" can function as a magnetic brake relative to the first torque amplifier element 110' and relative to the rotor 20. In practice, the first element 110' and the second element 110" can include magnets with opposite poles, such that when the first element 110' is rotated by the rotor 20, the magnet of the first element 110' is brought closer to the magnet of the second element 110". The magnet of the second element 110" then applies a magnetic repulsive force opposite to the torque of the rotor 20 and the first torque amplifier element 110' of the rotor 20.

[0030] Preferably, in the braking configuration, the second element 110" or brake is in mechanical contact with the first torque amplifier element 110' of the rotor 20. Therefore, the rotation of the second element 110" relative to the first element 110' and the rotor 20 acts as a mechanical stop. Thus, the second element 110" prevents any rotation of the first element 110' and the rotor 20 along the rotation axis X.

[0031] Preferably, the shape of the second element 110" matches the shape of the first element 110'.

[0032] Therefore, when the rotation of rotor 20 is no longer concentric, i.e., when the rotation axis X of rotor 20 can move in any way, rotor 20 drives the first element 110' to rotate due to its uneven motion and eccentricity. The first element 110' thus acts as a means of increasing the torque of rotor 20 by rotating together with rotor 20. The increased torque is thus detected by detection device 110 through the second element 110" which contacts the first element to prevent any rotation of rotor 20 and the first element 110'. Rotor 20 is then stopped before its rotation deteriorates excessively.

[0033] In other words, the detection device 110 is configured to switch from a stationary configuration to a braking configuration when the rotation of the rotor is eccentric relative to the rotation axis X. "Eccentricity" should be understood as meaning that the behavior and rotation of the rotor 20 deviate from the standard or expected rotation of the rotor 20, or even that the rotation of the rotor 20 no longer defines a concentric circle, but rather defines an elliptical or oval motion. Furthermore, the rotation of the rotor 20 defines a radius r, which is the distance between the rotation axis X and the surface 200 of the rotor 20 in a plane perpendicular to the rotation axis X, such as... Figure 1 As shown. Therefore, eccentricity is also the distance between the rotation axis X and the surface 200 of the rotor 20 when the rotational motion of the rotor 20 is no longer concentric in a plane perpendicular to the rotation axis X. Therefore, the eccentricity when the rotational motion of the rotor 20 is no longer concentric is greater than the radius r.

[0034] The roller bearing assembly 100 also includes a tolerance for rotation relative to the rotor 20. This tolerance is the radial distance to the rotor 20, specifically the distance along a defined radial axis R within which the rolling function of the roller bearing assembly 100 is performed. If the rotor 20 rotates, in other words, if the eccentricity of the rotor's rotation exceeds this operating tolerance, the roller bearing assembly 100 performs its rolling function relative to the rotor 20 in a degraded manner. Therefore, this tolerance can be understood as the clearance between the rotor 20 and the roller bearing assembly 100.

[0035] The first element 110' is also positioned adjacent to the rotor 20. The first element 110' therefore also includes a second tolerance for rotation relative to the rotor 20. Furthermore, as with the roller bearing assembly 100, this second tolerance is the radial distance to the rotor 20, i.e., the distance along the radial axis R. However, unlike the roller bearing assembly 100, the second tolerance expresses a threshold distance indicating whether the rotor 20 is operating properly or improperly. In other words, if the rotational movement of the rotor 20, or the potential eccentricity of the rotor 20 during rotation, remains less than the distance defined by the second tolerance, the rotor 20 operates normally. Therefore, the first element 110' is not driven by the rotor and the detection device 110 is in a stationary configuration. Conversely, if the potential eccentricity of the rotor 20 during rotation is greater than the distance defined by the second tolerance, the rotor 20 operates in a degraded manner. The first element 110' is then driven to rotate by the rotor 20, preferably with the rotor 20 in contact with the first element 110', and the detection device 110 subsequently switches to a braking configuration. Therefore, the first tolerance of the roller bearing assembly 100 is smaller than the second tolerance of the detection device 110. In this way, in the static configuration of the detection device 110, the rotor 20 is only in contact with the roller bearing assembly 100. Furthermore, in the braking configuration, the eccentricity that can be measured on the rotation of the rotor 20 allows the rotor 20 to drive the first element 110' to rotate and detect the eccentricity through the second element 110".

[0036] As an indicative example, for a roller bearing assembly 100 with a tolerance of 7 micrometers, i.e., a distance of 7 micrometers separating the surface 200 of the rotor 20 from the roller bearing assembly 100, it is conceivable that the second tolerance, or the distance between the surface 200 of the rotor 20 and the first element 110', is equal to 10 micrometers. Advantageously, it is conceivable that the distance between the surface 200 of the rotor 20 and the first element 110', i.e., the second tolerance, can be defined relative to the distance between the surface 200 of the rotor 20 and the roller bearing assembly 100. More specifically, the distance between the surface 200 of the rotor 20 and the first element 110', i.e., the second tolerance, can be defined according to the following formula: Where D2 represents the distance between the surface 200 of the separator rotor 20 and the first element 110, i.e., the second tolerance; D1 represents the distance between the surface 200 of the separator rotor 20 and the roller bearing device 100, i.e., the first tolerance; and x represents the eccentricity detection ratio.

[0037] Preferably, the eccentricity detection ratio x is greater than 1 and less than 1.5. In the ideal configuration, the eccentricity detection ratio x is equal to 1.2.

[0038] Preferably, the first element 110' is juxtaposed with the roller bearing assembly 100 relative to the rotation axis X. Therefore, from a viewpoint perpendicular to the plane of rotation axis X, the first element 110' and the roller bearing assembly 100 appear to be stacked. Thus, the first element 110' and the roller bearing assembly 100 are placed side-by-side, and preferably close to each other along the rotation axis X. The first element 110' and the roller bearing assembly 100 do not need to be connected.

[0039] Ideally, the first element 110' is fixed against the roller bearing assembly 100 to allow the detection device 110 to be as close as possible to the roller bearing assembly 100 to detect any eccentricity.

[0040] The first torque amplifier element 110' further includes at least one protrusion 410. The at least one protrusion 410 takes the form of a projection. The second braking element 110" includes a mechanical stop 420, which has a shape that matches the protrusion 410, thereby allowing at least one protrusion 410 to abut or press against the stop 420. Preferably, the first element 110' includes at least two protrusions 410, and the second braking element 110" includes the same number of mechanical stops 420.

[0041] Therefore, in the braking configuration, at least one protrusion 410 that bears the rotation of the first element 110' contacts the mechanical stop 420, which applies a force opposite to the rotational torque. Conversely, in the stationary configuration of the detection device 110, at least one protrusion 410 is away from the stop 420.

[0042] Furthermore, at least one protrusion 420 may preferably extend along the radial axis R.

[0043] As a variation, at least one protrusion 410 may extend parallel to the axis of rotation X. This architecture then allows the first element 110' and the second element 110" to be offset along the axis of rotation X to maintain the distance between the first element 110' and the second element 110" in the stationary configuration of the detection device 110.

[0044] Figure 2 It shows Figure 1 A cross-sectional view of the bearing in a plane parallel to the axis of rotation X.

[0045] In addition to the detection device 110, it is conceivable to add a mechanical fuse near the rotor. Then, when the detection device 110 switches to a braking configuration, the mechanical fuse allows for mechanical disengagement within the rotor 20. In fact, as described above, the braking configuration allows for a significant and sufficient braking force, opposite to the rotational torque of the rotor 20, to be generated by the second element 110" to activate and break the mechanical fuse. Therefore, when the rotation of the rotor 20 is no longer concentric, i.e., when the rotational axis X of the rotor 20 can move in any way, the rotor 20, due to its uneven motion and eccentricity, causes the first element 110' to rotate, which thus acts as a means of increasing the torque of the rotor 20 by rotating with it. The increased torque is thus detected by the detection device 110 through the second element 110" which contacts the first element 110' to generate sufficient frictional torque to break the fracture, i.e., the mechanical fuse, to prevent any further rotation of the rotor 20 and the first element 110'. The rotor 20 is then stopped before its rotation deteriorates excessively.

[0046] Figure 3 A schematic diagram of a preferred architecture of the first element 110' is shown, which allows for an increase in the torque of the rotor 20 when the rotor 20 rotates eccentrically. Preferably, the first element 110' is partially in the form of an annular ring and includes at least one concentric portion 405 adapted to the shape of the rotor 20. As described above, the first element 110' also includes at least one protrusion 410.

[0047] As described above, the rotor 20 is located away from at least one concentric portion 405. As an indicative example, the gap, i.e., the distance between the surface 200 of the rotor 20 and the concentric portion 405 of the first element 110', can be in the range of 0.001% to 0.05% of the diameter of the rotor 20. As an indicative example, the gap between the surface 200 of the rotor 20 and the concentric portion 405 of the first element 110' can be in the range of 0.02 mm to 5 mm.

[0048] Therefore, when the rotation of rotor 20 is no longer completely concentric and surface 200 contacts concentric portion 405, first element 110' is driven to rotate together with rotor 20 until protrusion 410 contacts stop member 420 and stops rotor 20 and first element 110' assembly.

[0049] As an indication, in order to drive the first element 110' to rotate through the contact between the surface 200 and the concentric portion 405, the frictional torque between the surface 200 and the concentric portion 405 must be greater than 0.5 Nm.

[0050] Advantageously, the first element 110' may also include a damping portion 415 disposed near the protrusion 405. More specifically, in a plane perpendicular to the rotation axis X of the rotor 20, a stop 420 of the second element 110' is included between the damping portion 415 of the first element 110' and the protrusion 410. In fact, since the local stress near the interface between the protrusion 410 and the stop 420 is very high, and, as an indication, greater than 800 MPa, the damping portion 415 supports these stresses by significant deformation to prevent any breakage of the first element 110'. The damping portion 415 acts as a compression spring to withstand local stresses during braking of the first element 110' and the rotor 20.

[0051] Second element 110" (e.g.) Figure 4 The first element 110' (shown) includes at least one stop 420, which is configured to interact directly with at least one protrusion 410 of the first element 110' when the first element 110' is rotated by the rotor 20.

[0052] Therefore, this invention proposes a "passive" disengagement device. In practice, during lubrication failure or slow or sudden bearing failure, the failure results in a loss of guidance for the bearing, roller bearing type, etc. The detection device 110 is then able to detect the revolution of the rotor 20 and generate a torque to resist the rotation of the rotor 20. This invention also avoids adding any additional controlled components beyond those required for operating the rotating machine, thus advantageously having no impact on volume and negligible weight impact.

Claims

1. A rotating machine comprising a coaxial rotor (20) and a stator (30), the rotor (20) being configured to rotate freely about a rotation axis (X), the rotating machine comprising at least one bearing (10) configured to guide the rotation of the rotor (20), the at least one bearing (10) contacting a surface (200) of the rotor (20), The bearing (10) includes a roller bearing assembly (100) extending concentrically around the rotor (20) and a detection device (110) for detecting rotational defects. The detection device (110) for detecting rotational defects includes a first element (110') and a second element (110"), the first element (110') extending concentrically around the rotor (20) and the second element (110") being rigidly connected to the stator (30). The detection device (110) is configured to switch from a static configuration to a braking configuration, in which the first element (110') is located away from the rotor (20) and the second element (110"), and in the braking configuration, the first element (110') is rotated by the rotor (20), and wherein the second element (110") applies a force on the first element (110') opposite to the rotation of the rotor (20). The detection device (110) is configured to switch from the stationary configuration to the braking configuration when the rotation of the rotor (20) is eccentric relative to the rotation axis (X).

2. The rotating machine according to claim 1, wherein, The first element (110') is juxtaposed with the roller bearing assembly (100) along the rotation axis (X).

3. The rotating machine according to claim 1, wherein, The roller bearing assembly (100) is at a first predetermined distance from the surface (200) of the rotor (20), wherein the first element (110') is at a second distance from the surface (200) of the rotor (20), the second distance being defined according to the following formula: Wherein, D2 represents the second distance separating the surface (200) of the rotor (20) from the first element (110), D1 represents the first distance separating the surface (200) of the rotor (20) from the roller bearing device (100), and x represents a predetermined eccentricity detection ratio.

4. The rotating machine according to claim 1, wherein, The first element (110') includes a protrusion (410), and wherein the second element (110") includes a stop (420) that contacts the protrusion (410) in the braking configuration and is away from the protrusion (410) in the stationary configuration.

5. The rotating machine according to claim 4, wherein, The protrusion (410) is defined relative to the rotor (20) along the radial axis (R).

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