Rotating electric machine for vehicle

Abstract

Title: Rotating electrical machine for vehicle The present invention relates to an electrical machine for vehicle, comprising a housing (7), a rotor / stator assembly housed within said housing (7) and at least one fixing flange (8, 8a, 8b) made in one piece with the housing (7) and configured to mechanically connect the rotating electrical machine to a heat engine of said vehicle, the fixing flange (8, 8a, 8b) comprising on the one hand a body (9) provided with a receiving opening (10) for a fixing means centered around a fixing axis (12) and on the other hand at least one lug (16, 16a, 16b) connecting the body (9) to the housing (7), characterized in that the fixing flange (8, 8a, 8b) comprises at least one fracture incipient (17) formed on the lug (16, 16a, 16b) and configured so that said lug (16, 16a, 16b) breaks in the event of a violent impact to the vehicle. (figure 4)

Description

Title of the invention: Rotating electric machine for vehicle

[0001] The present invention relates to the field of motor vehicles, and more particularly concerns a rotating electrical machine integrated within such motor vehicles.

[0002] In the automotive field, rotating electrical machines are commonly used as alternator-starters, and as such interact with the thermal engine of said vehicle. The alternator-starter allows on the one hand a starting function of the thermal engine, when the vehicle is stationary, via a belt connecting the rotating electrical machine to the crankshaft of the thermal engine, and on the other hand allows an alternator function when the vehicle is moving, consisting of the recovery of the mechanical energy of the thermal engine in order to generate electrical energy making it possible for example to power any electrical element of the vehicle.

[0003] It is understood from the above that in view of the interactions between the rotating electrical machine and the heat engine, these two elements are positioned close to each other and must be mechanically connected together in a precise and durable manner, thus forming an engine assembly, within the engine compartment of the vehicle. This implies having to position the rotating electrical machine as close as possible to the heat engine and in particular providing, on the housing of the rotating electrical machine, at least one fixing flange by means of which the rotating electrical machine is fixed to the heat engine.More particularly, a fixing flange of the rotating electrical machine is arranged opposite a fixing flange of the thermal engine and a suitable fixing means, for example a fixing screw, makes it possible to fix the position of the rotating electrical machine relative to the thermal engine and then to ensure the correct positioning of the transmission belt between these two elements of the engine assembly. This position of the rotating electrical machine as close as possible to the thermal engine may involve positioning it opposite certain fragile components of the thermal engine, such as for example a protective casing of an intake manifold of the thermal engine.

[0004] The design of motor vehicles, and in particular the layout of the engine compartment at the front of motor vehicles, must take into account the behavior of the various components equipping the vehicle during a violent impact suffered by the vehicle, and in particular a frontal impact, for example following an accident. In the previously mentioned context of an alternator-starter arranged opposite an intake manifold protection casing, the positioning and behavior of the alternator-starter during an impact suffered by the vehicle must be particularly designed to avoid deformation of the connection between the thermal engine and the alternator-starter and random movement of the alternator-starter which could generate a collision between the latter and the intake manifold, the protective casing being conventionally made of a material and with a thickness such that it may not withstand such a collision. The aim is thus to avoid creating a potential fuel leak at the intake manifold which can lead to extremely serious consequences, such as an explosion or a fire, particularly if the collision is due to an accident.

[0005] The present invention falls within this context and proposes as such a rotating electrical machine for a vehicle, comprising a housing, a rotor / stator assembly housed within said housing and at least one fixing flange made in one piece with the housing and configured to mechanically connect the rotating electrical machine to a thermal engine of said vehicle, the fixing flange comprising on the one hand a body provided with a receiving opening for a fixing means centered around a fixing axis and on the other hand at least one lug connecting the body to the housing, characterized in that the fixing flange comprises at least one fracture initiator formed on the lug and configured so that said lug breaks in the event of a violent impact suffered by the vehicle.

[0006] Due to the presence of the fracture initiator in the lug of the fixing flange, the invention makes it possible, in the event of a violent impact suffered by the vehicle and relative movements specific to each of the different components of the engine assembly under the effect of the impact, to separate the rotating electrical machine from the heat engine via a controlled mechanical break. This ensures that the connection between the rotating electrical machine and the heat engine is broken in a predictable manner, in accordance with the predictions made by the designers of the front compartment of the motor vehicle, by leaving a portion of the lug connected to the heat engine via the fixing means, which thus ensures that the casing of the rotating electrical machine, and the portion of the lug remaining attached to the casing, move under the effect of the impact without striking the heat engine and in particular the protective casing of the intake manifold.

[0007] The rotor / stator assembly comprises a stator and a rotor configured to rotate in or around the stator. Depending on the operating mode of the rotating electrical machine, the rotor may be rotated by the magnetic flux generated by an electrical supply of a winding of the stator, and subsequently transmit mechanical energy to the heat engine via a transmission belt driven by the rotation of an output shaft of the rotor, or conversely the rotor may be rotated via the movement of the transmission belt and the movement of the rotor generates a magnetic flux which is transformed via the electrical connection of the stator winding into an electrical current available for the vehicle's electrical components. The housing in which the rotor / stator assembly is housed guarantees mechanical protection, stability of the rotor / stator assembly, and optionally resistance to vibrations.

[0008] The fixing flange is made in one piece with the housing insofar as the latter is made for example by casting, if necessary by injection, and the part which results from this manufacturing process incorporates said flange. This fixing flange forms a lateral projection of the housing.

[0009] The body of the fixing flange may be in an annular shape delimiting the receiving opening of said fixing flange and centered around the fixing axis. The heat engine may also comprise such a type of fixing flange, an opening of which is also centered around the fixing axis. The fixing means connecting the rotating electrical machine to the heat engine is in particular a reversible fixing means, which may be a threaded rod passing through all of the fixing flanges and bolted at each end.

[0010] The lug constitutes the connection between the housing and the body. A fixing flange may comprise one or more lugs. The lug thus participates in the mechanical connection between the rotating electrical machine and the thermal engine. This lug is dimensioned so as to ensure that the fixing flange is held in place while the vehicle is running, and to ensure that the rotating electrical machine remains in the desired theoretical position relative to the thermal engine throughout the lifetime of the vehicle, or in any case throughout the lifetime of the rotating electrical machine and / or the thermal engine, except for violent impacts suffered by the vehicle. In particular, the thickness of the fixing lug, measured along the axial direction defined by the fixing axis associated with the fixing flange, is substantially equivalent to the thickness of the body of the fixing flange.

[0011] The fracture initiator being formed at the level of the lug, it is therefore the lug which breaks in the event of a violent impact suffered by the vehicle. More particularly, during such an impact, the presence of the fracture initiator makes it possible to ensure that the lug breaks with a part of the lug, arranged between the fracture initiator and the body of the fixing flange, which remains permanently on the thermal engine and another part of the lug which remains in one piece with the housing and moves with it at a distance from the body of the fixing flange.

[0012] The fracture initiation may be in the form of a notch or a groove formed in the thickness of the material of the lug. As mentioned, this fracture initiation makes it possible to promote the fracture of the lug in the event of an impact. It should however be noted that the fracture initiation is formed and sized so that the lug breaks only in the event of a violent impact suffered by the vehicle and not during the operation. normal operation of the engine assembly. In particular, the fracture initiation must not weaken the mounting bracket when the engine assembly is subjected to vibrations due to the vehicle being driven and / or when the vehicle experiences a small impact, for example during a parking maneuver. In other words, the shape and size of the fracture initiation must be determined by achieving a compromise between the desire for controlled fracture in the event of a violent impact and the need to have mechanical strength of the attachment of the rotating electrical machine to the thermal engine in standard operating mode, excluding violent impacts suffered by the vehicle.

[0013] Here, a violent shock suffered by the vehicle can be defined as a function of the speed of the vehicle before impact or as a function of the energy released during the impact, whether by the value of the impact force or the quantity of G released during the deceleration due to the shock.

[0014] According to a characteristic of the invention, the fixing flange comprises a first face and a second face opposite the first face, the first face and the second face being perpendicular to the fixing axis, the fracture initiation being positioned on the first face or on the second face. The first face and the second face are to be considered for the entire fixing flange, so that one can speak of a first face of the body and the lug of the fixing flange and a second face of the body and the lug of this fixing flange, opposite the first face of the body and the lug of the fixing flange.

[0015] According to a characteristic of the invention, the fracture initiator is positioned at the face which is opposite an area at which a vehicle impact is most likely. In other words, for a rotating electrical machine according to the invention present in a front compartment of a motor vehicle and for which particular attention is paid to the behavior during a frontal impact, the fracture initiator is positioned at the face which is turned towards the front of the vehicle. However, for reasons of size and / or mechanical feasibility of the fracture initiator, it is entirely possible to arrange the fracture initiator on the other face if the choice of positioning of said fracture initiator is limited.

[0016] According to a characteristic of the invention, the fracture initiator is a first fracture initiator positioned on the first face of the fixing flange, the fixing flange comprising at least one second fracture initiator positioned on the second face of the fixing flange and aligned with the first fracture initiator along a straight line parallel to the fixing axis. If the spatial environment allows, the fixing flange may comprise a fracture initiator on each face and aligned with each other. Such a configuration improves the precision of the fracture. in the event of an impact. The separation of the lug into two parts in the event of a violent impact suffered by the vehicle, at the level of the initiation of rupture, is thus initiated on each of the faces and it is thus possible to more effectively aim for a clean rupture plane, substantially parallel to the direction of the frontal impact, which makes it possible to better control the subsequent movement of the rotating electrical machine in relation to the thermal engine.

[0017] According to a characteristic of the invention, the fixing flange comprises two lugs arranged on either side of the body, the rotating electrical machine comprising at least one fracture initiator formed on each lug. If the fixing flange comprises two lugs, it is advantageous to arrange at least one fracture initiator on each of them in order to ensure that the two lugs break in the event of an impact so that the body is completely separated from the fixing flange.

[0018] According to a characteristic of the invention, the housing is formed of two half-housings, each half-housing comprising a fixing flange with a receiving opening for a fixing means centered around the fixing axis, each fixing flange comprising at least one fracture initiator. The formation of the housing in two half-housings, or two half-shells, makes it easier to position the rotor / stator assembly inside the housing. The fact of having several fixing flanges, with at least one fixing flange per half-housing, helps to strengthen the mechanical connection between the rotating electrical machine and the thermal engine. However, within the scope of the invention, the rotating electrical machine must separate from the thermal engine in the event of a violent impact suffered by the vehicle. This implies a breakage of each of the fixing flanges regardless of their number.Thus, in the event of the presence of a plurality of fixing flanges, each of them advantageously comprises at least one initiation of rupture so that an impact causes the rupture of all of said fixing flanges.

[0019] According to a characteristic of the invention, the at least one fracture initiation point has a depth of between 10 and 40% of a thickness of the lug, said thickness being measured between the first face and the second face of the fixing flange. As mentioned previously, the depth of the fracture initiation point must be determined by making a compromise between the desire for controlled fracture in the event of a violent impact and the need to have mechanical strength of the fixing of the rotating electrical machine to the heat engine. This depth of the fracture initiation point is dependent on both the thickness of the lug and the mechanical strength of the lug, and in particular on the material used to make this lug and the casing of the rotating electrical machine as a whole.It is thus understood that the ratio between the depth of the fracture initiation and the thickness of the leg can vary from one rotating electrical machine to another depending on the type of material used. It has been specified that it is at least one fracture initiation which has a depth of between . between 10 and 40% of a thickness of the tab, to the extent that this depth value can be achieved just as well with a single fracture initiator if a single fracture initiator is provided on the tab or by adding the depths of two fracture initiators if these two fracture initiators are aligned on a fixing tab by being arranged on opposite faces. Thus, in the case where, for reasons of mechanical size, it is not possible to implement a fracture initiator on each face aligned with each other, it is possible instead to implement a single fracture initiator on a single face but whose depth is equivalent to the sum of the depths of two aligned fracture initiators.

[0020] According to a characteristic of the invention, the fracture initiator has a curvature oriented around the body. A curved initiator makes it possible in particular to partially match a contour of the receiving opening of the body. This allows a cleaner fracture in the event of an impact and which provides the assurance of a fracture only at the level of the tab. The risk of a fracture extending beyond the tab and potentially creating additional damage is greatly limited.

[0021] According to a characteristic of the invention, the fracture initiation extends along the entire length of the lug in a direction perpendicular to the fixing axis. Such a configuration is preferential if the surrounding mechanical size and / or the structure of the rotating electrical machine allows it. Like most of the characteristics described previously, this is a configuration ensuring a cleaner and more precise fracture after an impact.

[0022] According to a characteristic of the invention, the tab is configured to break at the level of the initiation of rupture when the vehicle undergoes a violent impact with an impact force greater than a threshold value of the order of 4400 N. This threshold value is for example defined for a machine of the order of 10 kg. Such an impact force threshold value is sufficiently high to prevent the fixing flange from breaking during normal operation of the rotating electrical machine, but also sufficiently low for the fixing flange to break at the level of the initiation of rupture following a violent impact suffered by the vehicle.

[0023] The invention also covers a motor assembly of a vehicle, comprising a heat engine, a rotating electrical machine as described above, and a fixing means connecting the rotating electrical machine to the heat engine, the fixing means being arranged opposite a protective part of the heat engine. Thus, the breaking of the fixing flanges makes it possible to prevent the fixing means from striking and damaging the protective part, in particular a protective part of the intake manifold of the heat engine, and from aggravating the situation.

[0024] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and of several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0025] [Fig. 1] is a partial representation of a vehicle engine assembly comprising a rotating electrical machine according to the invention and a heat engine on which the rotating electrical machine is fixed at least at the level of a fixing flange,

[0026] [Fig.2] is a perspective view of the rotating electrical machine according to the invention, making visible in particular two fixing flanges respectively formed on a half-housing of the rotating electrical machine, each fixing flange having at least one incipient fracture,

[0027] [Fig.3] is a perspective view of the rotating electrical machine according to the invention and a protective cover also visible in [Fig.l], here without the associated thermal engine, this view from the front of the vehicle making it possible to account for the transverse positioning of the rotating electrical machine in relation to the protective cover and the interest of the fracture incipients on the fixing flanges,

[0028] [Fig.4] is a first detailed view of the fixing flanges of the electric machine rotating [Fig.2], perspective views from the front of the vehicle,

[0029] [Fig.5] is a second detailed view of the fixing flanges of the electric machine rotating [Fig.2], side views,

[0030] [Fig.6] is a detail view of a first case, in which a tab of a flange of fixing comprises two aligned fracture incipients formed on two opposite faces of this tab,

[0031] [Fig.7] is a detail view of a second case, in which a tab of a flange of fixing has a single fracture initiation,

[0032] [Fig.8] is a third detailed view of the machine housing mounting flanges rotating electric motor of [Fig.2], perspective views from the rear of the vehicle.

[0033] [Fig.l] is a representation of an engine assembly 1 that can be integrated into a motor vehicle. The engine assembly 1 comprises a rotating electrical machine 2 and a heat engine 3 interacting with each other. The rotating electrical machine 2 comprises a rotor / stator assembly 4 connected to a belt 5 which, in a manner not illustrated, is also connected to a crankshaft of the heat engine 3. Thus, the rotating electrical machine 2 is able to interact with the heat engine 3 via the belt 5.

[0034] The rotating electrical machine 2 here acts as an alternator-starter, capable of providing both a function of assisting in starting the motor vehicle and a function of recovering electrical energy. When starting the vehicle, a rotor of the rotor / stator assembly 4 is set in rotation, via its magnetic elements and for example permanent magnets, by a magnetic field created following a power supply electrical supply of a stator winding, the rotational movement of the rotor then driving a pulley 6 arranged at the end of the output shaft of the rotor and around which the belt 5 is arranged subsequently allowing the thermal engine 3 to be driven. Conversely, during the rolling of the vehicle, the thermal engine 3 drives the belt 5 in movement, which itself drives the rotor in rotation, via the pulley 6, and the rotor / stator interaction and the electronic components associated with the stator winding make it possible to convert mechanical energy into electrical energy.

[0035] The rotor / stator assembly 4 of the rotating electrical machine 2 is housed in a housing 7. The latter provides the function of protection and mechanical maintenance of the rotor / stator assembly 4, only the pulley 6 associated with the rotor extending outside the housing 7 so that the movement can be transmitted from the rotor to the belt 5 or vice versa.

[0036] It is understood from the above that the rotating electrical machine 2 and the heat engine 3 interact mechanically with each other and must therefore be mechanically connected to each other in a solid and stable manner. Therefore, the motor assembly 1 comprises one or more fixing means ensuring the mechanical connection between the rotating electrical machine 2, more particularly the housing 7 of the rotating electrical machine 2, and the heat engine 3. To do this, the housing 7 comprises at least one fixing flange 8, which comprises a body 9 delimiting an opening 10, and the heat engine 3 comprises a fixing member 11 also provided with an opening, said opening not being visible in [Fig.l].

[0037] The openings of the at least one fixing flange 8 and of the fixing member 11 are aligned with each other and centered around a fixing axis 12. The associated fixing means may for example be a fixing screw or a threaded rod, which extends axially, along the fixing axis 12, through all of the openings and which cooperates with at least one nut to thus guarantee the mechanical connection between the rotating electrical machine 2 and the thermal engine 3. It should be noted that only the fixing axis 12 is visible in [Fig.l], the fixing means having been removed to make the at least one fixing flange 8 more particularly visible.

[0038] As illustrated in [Fig.l], the arrangement of the engine assembly 1 is here configured so that the rotating electrical machine 2 is arranged laterally opposite a lateral face of the heat engine 3 on which all or part of an exhaust manifold is arranged.

[0039] In this arrangement, the fixing means and the associated fixing flange 8 are positioned opposite, considering the longitudinal direction of the fixing axis 12 along the lateral face of the heat engine, a protective part 13 of the intake manifold, which projects from said lateral face of the heat engine. Such a protective part 13 theoretically prevents damage to the manifold intake and / or the connection of an air / fuel supply hose to this manifold.

[0040] The protective part 13 is however not configured to withstand an impact force resulting from a violent shock. In particular, the protective part 13 may consist of a thin folded sheet metal. If the vehicle suffers a violent shock, for example following a collision of the vehicle with an obstacle or a third-party vehicle, the theoretical position of the rotating electrical machine 2 relative to the heat engine 3 may be modified by a deformation of the fixing means and the rotating electrical machine may then come into contact with the protective part 13 and the latter may not withstand such an impact. This can thus seriously damage the intake manifold and create a fuel leak which can significantly worsen the situation of the vehicle beyond the shock suffered.

[0041] A solution to this problem is illustrated more precisely in [Fig.2], which makes the rotating electrical machine 2 and in particular the at least one fixing flange 8 more visible.

[0042] In [Fig.2], it is possible to observe that the housing 9 is composed of two half-housings 14 fixed to each other to protect the rotor, here removed to simplify the figure, and the stator 15 of the rotor / stator assembly 4, and each of these half-housings 14 comprises a fixing flange 8 arranged on the periphery of said half-housings 14. Thus, the rotating electrical machine comprises a first half-housing 14a provided with a first fixing flange 8a and a second half-housing 14b provided with a second fixing flange 8b.

[0043] Each fixing flange 8, 8a, 8b is made in one piece with the half-housing 14, 14a, 14b associated with it. Here, each half-housing is a casting which is subsequently added and screwed against the other half-housing and the fixing flanges 8 are formed during the casting operation making it possible to obtain this half-housing.

[0044] As previously described, the fixing flanges 8 each comprise a body 9 which delimits an opening 10 configured to be centered around the fixing axis 12. Each fixing flange 8 also comprises at least one tab 16 mechanically connecting the body 9 of the fixing flange 8 to the half-housing 14 in question. The average thickness of a tab is substantially the same as that of the body, in particular to ensure mechanical strength of the body of the fixing flange so that it does not risk breaking under the effect of vibrations generated during rolling at the junction between the heat engine and the rotating electrical machine.

[0045] The particularity of the rotating electrical machine 2 according to the invention is that each fixing flange 8 comprises at least one fracture incipient 17 formed at one of the lugs 16. Preferably, in the case where the body of the fixing flange is held by several lugs, each lug 16 of this fixing flange 8 includes a break initiator 17.

[0046] It is understood that it is at the level of the initiation of rupture 17, which forms a zone of local reduction in the thickness of the lug, that a rupture of material, that is to say a rupture of the lug 16, will take place as a priority. Thus, in the event of a violent impact suffered by the vehicle, it is the lugs 16 of the fixing flanges 8 which will break, thus separating a part of the fixing flanges 8 from the rest of the rotating electrical machine 2. More particularly, in the event of a violent impact, the presence of an initiation of rupture 17 on a lug 16 generates a separation of the corresponding lug into two parts, with a part of the lug remaining integral with the corresponding housing or half-housing and a part of the lug linked to the body 9 of the fixing flange still held in place on the fixing member 11 of the thermal engine via the fixing means.

[0047] The mechanical connection between the rotating electrical machine 2 and the thermal engine is thus interrupted in the event of a violent impact thanks to the presence of one or more break points, thus preventing elements of the engine assembly, whether the casing of the rotating electrical machine or the fixing means held in place on the thermal engine, from coming into contact with the protective part described above. Any worsening of the incident responsible for the impact of the vehicle via a fuel leak resulting from damage to the intake manifold of the thermal engine is thus avoided.

[0048] [Fig. 3] represents a view of the rotating electrical machine 2 and of the part of protection 13 alone, without the heat engine on which it is attached. This figure presents an angle of view making it possible to account for the interest of the incipient fractures and their location on the lugs of the at least one fixing flange. Following a violent impact suffered by the vehicle, that is to say a frontal or substantially frontal impact of the vehicle against an obstacle or a third-party vehicle, with a direction of the impact force which is represented by the white arrow in [Fig. 3], the casing of the rotating electrical machine 2 is likely to move in this direction relative to the heat engine and therefore relative to the protection part 13 once the lugs of the fixing flanges have broken.

[0049] Thanks to the fracture incipients 17, during the impact suffered by the vehicle, the legs 16 are broken at a predetermined location, in a fracture plane shown in dotted lines and comprising on the one hand the direction of the impact and on the other hand the direction of alignment of the fracture incipients. It is notable that the protective part is arranged on the same side of this plane as the portions of the fixing flanges 8, namely the bodies 9 and a part of the legs, which remain permanently on the heat engine. The rest of the rotating electrical machine can move relative to the heat engine with a minimal risk, because controlled, of encountering the protective part 13. are deso lidarized of the rotating electric machine 2. In other words, the rotating electric machine 2 does not strike or only lightly strikes the protective part 13 which can remain in position and then remain able to protect the intake manifold.

[0050] As mentioned, the fracture initiation 17 forms a zone of local reduction in the thickness of the tab, measured in the longitudinal direction, it being understood that the main component of forces of the impact force during a violent impact, i.e. a frontal impact, suffered by the vehicle is a longitudinal component. This local reduction in the thickness formed by the fracture initiation 17 can just as easily be carried out on the tab after obtaining the corresponding housing of the rotating electrical machine, in particular by machining a notch, or else be formed directly in the material of the tab 16 during a step of injection molding or casting of the corresponding housing.

[0051] The characteristics of each fracture initiator 17, such as the length or depth thereof, are defined according to a compromise according to which said fracture initiators 17 must force the fracture of the lugs 16 of the fixing flanges 8 during a violent impact suffered by the vehicle, but must not impact the rigidity and the holding of these lugs 16 due to vibrations or other standard mechanical constraints during the normal operation of the engine assembly. As will be detailed later, the compromise to be found for these characteristics depends in particular on a thickness of the lug 16 and can be impacted by the mechanical size of the surrounding engine assembly around the lug 16.

[0052] [Fig.4] is a more detailed view of the first fixing flange 8a and the second fixing flange 8b of the rotating electrical machine described and illustrated in [Fig.2],

[0053] [Fig. 4] makes it possible in particular to observe that each fixing flange 8 comprises a first face 18 and a second face 19 opposite the first face 18, each of these faces 18, 19 being perpendicular, or substantially perpendicular in particular due to manufacturing tolerances, to the fixing axis 12 of the fixing flanges 8. The first face 18 of the fixing flanges 8 is here the face which is oriented towards the front of the vehicle, so as to be opposite a potential frontal impact suffered by the vehicle.

[0054] Furthermore, each fixing flange 8 here comprises two tabs 16 and [Fig.4] shows that each of the tabs 16 comprises at least one breaking point 17 in order to ensure that the two tabs 16 of the fixing flange 8 break correctly.

[0055] Preferably, the rupture initiators 17 are positioned at the level of the first face 18 of each fixing flange 8, that is to say more generally at the level of the face 18, 19 which is directly opposite the road scene on which the potential impact will occur.

[0056] This is particularly visible at the level of the second fixing flange 8b, whether in [Fig.4] or [Fig.5] in particular. This second fixing flange 8b comprises a first tab 16a and a second tab 16b arranged on either side of the body 9, each of these tabs being provided with a breaking incipient point 17 at the level of the first face 18. The two tabs 16 of the second fixing flange 8b can thus break simultaneously or substantially simultaneously and in a precise manner, thus causing optimal separation of the body 9 from the rest of the housing in the event of a significant impact. It should be noted that in [Fig.4] the second fixing flange 8b comprises at the level of the body 9, in the receiving opening, a sleeve 20. For reasons of clarity and visibility of the breaking incipient points on the tabs, the sleeve 20 is not illustrated in all the figures.

[0057] As can be seen in [Fig. 4], the fracture incipients 17 formed on the same fixing flange may have different dimensions. More particularly, the fracture incipient 17 formed on the first face 18 of the first tab 16a of the second fixing flange 8b extends over an entire transverse dimension of the first tab 16a, in a direction perpendicular to the fixing axis 12, while the fracture incipient 17 formed on the first face 18 of the second tab 16b of this same second fixing flange 8b extends only partially over this equivalent transverse dimension of the second tab. It should be noted that to promote controlled rupture under the impact force, it may be preferred that the fracture incipient 17 extends over the entire transverse dimension of the tab 16 in order to improve the precision of the cutting into two parts of the tab during rupture.However, if the surrounding mechanical size of the fixing flange 8 does not allow this, it is possible to implement a less transversely extended rupture initiator 17 as is the case for the rupture initiator 17 of the second tab 16b of the second fixing flange 8b.

[0058] Furthermore, the second fixing flange 8b also includes a break initiation point on its second face 19, as will be detailed below with reference to FIGS. 5 and 8 which make this second face more visible.

[0059] The first fixing flange 8a also comprises a first tab 16a and a second tab 16b, with a fracture initiator 17 on each of them. However, the distribution of the fracture initiators is different on this first fixing flange insofar as on the first tab 16a, a fracture initiator is arranged on the first face 18 as well as on the second face 19 of this first fixing flange 8a, while the second tab 16b has a single fracture initiator 17 arranged on the second face 19 of the first fixing flange 8a. Even if such a positioning of a single fracture initiator on the second face is not the most advantageous, it is a possible alternative in the case where it is not possible to position the fracture initiator at the level of the first face 18. In this case, the geometry of the first face 18 of the first fixing flange 8a, particularly at the level of the second tab 16b thereof, does not allow the implementation of a fracture initiator 17 at the level of the first face 18. The fracture initiator 17 of the second tab 16b of the first fixing flange 8a is therefore positioned at the level of the second face 19.

[0060] [Fig. 5] is a side view of the fixing flanges 8 as illustrated in the preceding figures. The side view makes it possible to illustrate more clearly a characteristic of the rotating electrical machine according to which the first tab 16a of each fixing flange 8 comprises a first fracture initiator 17a positioned on the first face 18 of each fixing flange 8 and a second fracture initiator 17b positioned on the second face 19 of each fixing flange 8.

[0061] For each first leg 16a of the two fixing flanges 8, the first fracture initiation point 17a and the second fracture initiation point 17b are aligned with each other along a straight line parallel to the fixing axis 12. This configuration is ideal because it makes it possible to determine with great precision at which location the first leg 16a must be broken and improves the sharpness of the break which must extend from the first face 18 to the second face 19 of the first leg 16a.

[0062] Just like certain configurations mentioned previously, implementing a first rupture initiator 17a and a second rupture initiator 17b aligned with each other is advantageous but is only feasible if the spatial configuration of the fixing flange 8 allows it.

[0063] For the two fixing flanges 8, this configuration is possible to implement at the level of the first leg 16a but not at the level of the second leg 16b.

[0064] As described previously, the spatial configuration of the second tab 16b of the first fixing flange 8a does not allow the implementation of a break initiation 17 at the level of the first face 18. Concerning the second fixing flange 8b, it is at the level of the second face 19 that it is not possible to implement a break initiation 17 on the second tab 16b.

[0065] Whatever the configuration chosen for producing at least one fracture initiator on a tab of a fixing flange, namely either two fracture initiators 17a, 17b formed on opposing faces 18, 19 of the tab and aligned with each other with reference to the fixing axis 12 or a single fracture initiator formed on one of the faces, the ratio between the remaining material thickness of the tab and the void created by the fracture initiator(s) must be substantially the same and meet the criteria defined by the desired compromise between the mechanical strength of the tab and the possibility of fracture in the event of a violent impact. In other words, the presence of a single fracture initiator on a single face as mentioned for the second tabs 16b of each fixing flange can be compensated by increasing the depth of the single fracture incipient point 17.

[0066] More particularly, the depth of each fracture initiator 17 is dependent on the thickness 21 of the tabs 16 on which the fracture initiator(s) are positioned and on the presence or absence on the opposite face of another fracture initiator. Thus, as mentioned previously, the at least one fracture initiator 17 associated with a tab 16 has a depth of between 10 and 40% and, for example more precisely between 15% and 35%, of the thickness 21 of the tab 16 in the zone where said at least one fracture initiator 17 is positioned. The thickness of the tab and the depth of the fracture initiation are measured parallel to the fixing axis 12. The thickness of the tab is measured between the first face 18 and the second face 19 thereof, while the depth of the fracture initiation is measured between the face in which the fracture initiation is formed and the bottom of this initiation.

[0067] In a first case, illustrated schematically in [Fig.6], here the case of the first tabs 16a of the fixing flanges 8a, 8b, with the tab which comprises a first fracture initiation point 17a and a second fracture initiation point 17b aligned with each other, it is the sum of the depths Pa, Pb of each fracture initiation point 17a, 17b which should be considered and it is this sum of the depths which has a value between 10 and 40% of the thickness 21 of the tab 16 mentioned. Here, the depth of each fracture initiation point is substantially the same, without this being limiting of the invention since the sum of the depths meets the criterion which has just been mentioned.

[0068] In a second case, illustrated schematically in [Fig.7], here the case of the second tabs 16b of the fixing flanges 8a, 8b, with the tab which comprises a single fracture initiation point 17, it is the depth P of the single fracture initiation point 17 which should be considered and it is this depth value P which is between 10 and 40% of the thickness 21 of the tab 16 mentioned.

[0069] As mentioned, in each of the cases, the choice of the limits of the interval, in which the value of the depth of an incipient rupture or the value of the sum of the depths must be included, is made by considering the compromise between the desire for a controlled rupture in the event of a violent impact and the need to have mechanical strength of the attachment of the rotating electrical machine to the thermal engine in standard operating mode, excluding violent impact suffered by the vehicle.

[0070] The view of [Fig. 8] allows mainly the second face 19 of each fixing flange to be observed. Therefore, the fracture incipients 17 particularly visible in [Fig. 8] are the fracture incipients 17 positioned on the second face 19 of the fixing flanges 8, namely the second fracture incipient 17b of the first tab 16a of the first fixing flange 8a, the fracture incipient 17 of the second tab 16b of the first fixing flange 8a and the second fracture initiation 17b of the first leg 16a of the second fixing flange 8b.

[0071] A particularly visible feature in [Fig.8] can be observed at the second fracture initiation point 17b of the first leg 16a of the first fixing flange 8a, which has a curvature 22 oriented around the body 9 of the first fixing flange 8a. This curvature 22 also helps to improve the precision of the fracture of the leg 16. More particularly, the curvature 22 ensures that only the leg 16 breaks and that the fracture is correctly delimited. This makes it possible to avoid an unwanted fracture of another part of the housing of the rotating electrical machine arranged in the vicinity of the leg 16.

[0072] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention.

[0073] The invention, as just described, achieves the aim it set itself, and makes it possible to propose a rotating electrical machine comprising fixing flanges capable of breaking in the event of a violent impact and thus avoiding additional consequences resulting from such a violent impact. Variants not described here could be implemented without departing from the context of the invention, provided that, in accordance with the invention, they comprise a rotating electrical machine in accordance with the invention.

Claims

Claims

1. Rotating electrical machine (2) for a vehicle, comprising a housing (7), a rotor / stator assembly (4) housed within said housing (7) and at least one fixing flange (8, 8a, 8b) made in one piece with the housing (7) and configured to mechanically connect the rotating electrical machine (2) to a heat engine (3) of said vehicle, the fixing flange (8, 8a, 8b) comprising on the one hand a body (9) provided with a receiving opening (10) for a fixing means centered around a fixing axis (12) and on the other hand at least one lug (16, 16a, 16b) connecting the body (9) to the housing (7), characterized in that the fixing flange (8, 8a, 8b) comprises at least one fracture incipient (17) formed on the lug (16, 16a, 16b) and configured to that said tab (16, 16a, 16b) breaks in the event of a violent impact suffered by the vehicle.

2. Rotating electrical machine (2) according to claim 1, wherein the fixing flange (8, 8a, 8b) comprises a first face (18) and a second face (19) opposite the first face (18), the first face (18) and the second face (19) being perpendicular to the fixing axis (12), the fracture initiator (17) being positioned on the first face (18) or on the second face (19).

3. Rotating electrical machine (2) according to the preceding claim, in which the fracture initiator (17) is a first fracture initiator (17a) positioned on the first face (18) of the fixing flange (8, 8a, 8b), the fixing flange (8, 8a, 8b) comprising at least a second fracture initiator (17b) positioned on the second face (19) of the fixing flange (8, 8a, 8b) and aligned with the first fracture initiator (17a) along a straight line parallel to the fixing axis (12).

4. Rotating electrical machine (2) according to any one of the preceding claims, in which the fixing flange (8, 8a, 8b) comprises two tabs (16, 16a, 16b) arranged on either side of the body (9), the rotating electrical machine (2) comprising at least one fracture initiator (17) formed on each tab (16, 16a, 16b).

5. A rotating electrical machine (2) according to any preceding claim, wherein the housing (7) is formed of two half-housings (14, 14a, 14b), each half-housing (14, 14a, 14b) comprising a fixing flange (8, 8a, 8b) with a receiving opening (10) for a fixing means centered around the fixing axis (12), each fixing flange (8, 8a, 8b) comprising at least a start of rupture (17).

6. Rotating electrical machine (2) according to any one of the preceding claims, in which the at least one fracture incipient point (17) has a depth of between 10 and 40% of a thickness (21) of the lug (16, 16a, 16b), said thickness (21) being measured between the first face (18) and the second face (19) of the fixing flange (8, 8a, 8b).

7. Rotating electrical machine (2) according to any one of the preceding claims, in which the fracture initiator (17) has a curvature (22) oriented around the body.

8. Rotating electrical machine (2) according to any one of the preceding claims, in which the fracture initiation point (17) extends along the entire length of the lug (16, 16a, 16b) in a direction perpendicular to the fixing axis (12).

9. Rotating electrical machine (2) according to any one of the preceding claims, in which the tab (16, 16a, 16b) is configured to break at the level of the breaking point (17) when the vehicle undergoes a violent shock with an impact force greater than a threshold value of the order of 4400 N.

10. Engine assembly (1) of a vehicle, comprising a heat engine (3), a rotating electrical machine (2) according to any one of the preceding claims, and a fixing means connecting the rotating electrical machine (2) to the heat engine (3), the fixing means being arranged opposite a protective part (13) of the heat engine (3).

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