Parking brake device integrated in an electric machine

Abstract

The invention relates to a parking brake device (100) suitable for being installed in a housing of an electric machine (10) which houses a rotary shaft (21) and at least one bearing (30) for guiding the rotary shaft, said parking brake device comprising an annular support (110) which is suitable for being positioned between said bearing and said housing and which supports a parking brake mechanism (140) suitable for blocking the rotation of the rotary shaft, as well as measuring means (130) suitable for measuring the position or the angular velocity of the rotary shaft and / or electrical conduction means (120) between the rotary shaft and the housing.

Description

DESCRIPTION TITLE OF THE INVENTION: PARKING BRAKE DEVICE INTEGRATED INTO AN ELECTRIC MACHINE TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates generally to the braking of motor vehicles.

[0002] It relates more particularly to a device having a parking brake function.

[0003] It also relates to an electrical machine equipped with such a device and a motor vehicle comprising such an electrical machine. STATE OF THE ART

[0004] There are different types of parking brakes.

[0005] For example, we know of hand brakes, which have a handle allowing you to pull a metal cable connected to a brake shoe adapted to block the rear wheels of the vehicle.

[0006] We also know electric parking brakes which include an actuator which again allows the operation of cables connected to brake shoes.

[0007] Although this second system saves space compared to the first, it is still bulky and also comes at a significant cost.

[0008] Document DE102017217829 discloses a device arranged differently and usable on electric vehicles. In this document, the braking device comprises a ratchet mechanism which is adapted to lock onto a toothed wheel fixed to the shaft of the vehicle's electric motor. Thus, this device makes it possible to block the rotation of the electric motor shaft and, consequently, that of the vehicle's wheels.

[0009] In this document, the toothed wheel is fixed to the end of the electric motor shaft, against the drive pinion of the drive wheels.

[0010] However, this device remains bulky. Furthermore, it does not reduce the noise of the electric motor. PRESENTATION OF THE INVENTION

[0011] In order to overcome the aforementioned drawbacks of the state of the art, the present invention proposes to place the parking brake as close as possible to the engine.

[0012] More particularly, the invention provides a parking brake device suitable for being installed directly in an electric machine casing, which casing houses at least part of a rotating shaft and at least one bearing. guiding said rotating shaft.

[0013] According to the invention, this parking brake device comprises an annular support which is adapted to be interposed (radially) between said bearing and said casing and which carries: - a parking brake mechanism adapted to block the rotation of the rotary shaft relative to the casing, as well as: - measuring means adapted to measure the position or angular velocity of the rotating shaft relative to the casing, and / or electrical conduction means adapted to conduct the electric current between the rotating shaft and the casing.

[0014] The annular nature of the support allows this support to be placed around the rotating shaft of the electric machine, between the outer ring of the bearing and an opening made in the casing.

[0015] Thus, thanks to the invention, the elements that this annular support carries can be positioned in the casing of the electric machine, as close as possible to the rotor, in a space that was previously left free. The device then proves to be space-saving and is installed in a protected and lubricated space, which guarantees its proper functioning at low cost and in the long term.

[0016] The advantage of placing the annular support between the casing and the bearing is that this support can then reduce rolling noise. If it is made of a suitable material, it can in fact have a greater stiffness than that of the casing, which will reduce vibrations and therefore noise.

[0017] Typically, when this support is made of gray cast iron, it helps to absorb the acyclisms of the rotating shaft and to ensure good lubrication around the bearing when the latter rotates at very high speed and enters into "levitation".

[0018] This support, when made of a suitable material, can also have a coefficient of expansion closer to that of the bearing than the housing, so that the clearance around the bearing will be less sensitive to thermal variations, which will further reduce noise.

[0019] By reducing vibrations, this support will also ensure a longer lifespan for the entire electrical machine.

[0020] Finally, it should be noted that the advantage of placing this parking brake device as close as possible to the rotor of the electric machine, and not near the vehicle's wheels, is that the braking torque it will have to provide to block the vehicle will be lower than that which it would have to provide if it were placed at the wheels. In fact, this braking torque will be divided by the speed reduction ratio provided between the rotating shaft of the motor and the wheels. It is therefore possible to use a brake device of smaller dimensions.

[0021] Another aspect of the invention is that the annular support carries components to ensure different functions. This aspect has several advantages. The first is that it allows the number of components of the electrical machine to be reduced since a single support carries several functions. The second is that it allows these components to be assembled outside the electrical machine, which facilitates this assembly. The third is that all the forces exerted on these components are taken up by the annular support, which is sized based only on the component generating the most force. The third is that this assembly guarantees the coaxiality of the components and therefore ensures their proper functioning.

[0022] Finally, it should be noted that the installation of this braking device in the casing involves the installation of a toothed wheel on the rotating shaft of the electric machine to ensure the parking brake function. This toothed wheel will then advantageously increase the rigidity of the shaft and thus prevent it from bending excessively.

[0023] Other advantageous and non-limiting characteristics of the device according to the invention, taken individually or in all technically possible combinations, are the following: - the annular support carries measuring means and electrical conduction means; - said electrical conduction means are adapted to be inserted between the bearing and the measuring means; - the parking brake mechanism comprises a means for hooking a toothed wheel which is fixed to said rotating shaft, and an actuator adapted to move the hooking means between a position hooked to the toothed wheel and a position unhooked from the toothed wheel - the electrical conduction means comprise a ring fixed to the annular support and flexible electrical conduction elements which rest on a part of the toothed wheel; - there is provided, between the actuator and the hooking means, an elastically deformable part adapted to allow the actuator to move when the hooking means is blocked by the toothed wheel; - the measuring means comprise a position sensor adapted to determine the position of a washer fixed to the rotating shaft; - the annular support is formed from a single piece, and is preferably made at least partly of cast iron; - the annular support delimits an internal face of which a cylindrical part of revolution accommodates said bearing, and an external face of which a cylindrical part of revolution is adapted to be installed in an opening of the casing.

[0024] The invention also provides an electric machine comprising a casing, a rotor housed in the casing, a rotary shaft which is fixed to the rotor and which is pivotally mounted in the casing by means of at least one bearing, and a parking brake device as mentioned above.

[0025] Furthermore, the parking brake device of said machine may comprise a lever adapted to tilt around a tilting axis to block the rotation of the rotary shaft relative to the casing, the parking brake device comprises an annular support: - which is adapted to be interposed between said bearing and said casing, - which carries said lever, and - which is fixed to the casing by a fixing screw passing through said rocker axis.

[0026]

[0011] It also relates to a motor vehicle comprising a chassis, wheels and an electric machine as mentioned above, the rotating shaft of which is coupled to at least part of said wheels.

[0027] Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive. DETAILED DESCRIPTION OF THE INVENTION

[0028] The description which follows with reference to the appended drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented.

[0029] On the attached drawings:

[0030] [Fig. 1] is a schematic exploded perspective view of part of an electrical machine according to the invention;

[0031] [Fig. 2] is a schematic perspective view of the annular support and grounding washer of the electric machine of Fig. 1;

[0032] [Fig. 3] is a sectional view of a detail of the electrical machine of Fig. 1;

[0033] [Fig. 4] is an exploded perspective schematic view of the ring support, position sensor, toothed wheel and target of the electric machine of Fig. 1;

[0034] [Fig. 5] is an exploded perspective schematic view of a portion of the parking brake device of the electric machine of Fig. 1.

[0035] [Fig. 6] is a schematic sectional view of a portion of the parking brake device of Fig. 5; and

[0036] [Fig. 7] is a schematic sectional view of an alternative embodiment of the part of the parking brake device shown in Figure 6.

[0037] In Figure 1, an electrical machine 10 of a motor vehicle is shown.

[0038] This motor vehicle could be of any type. For example, it could be a car with a classic chassis and wheels.

[0039] This car has an electric or hybrid engine. It is therefore equipped with at least one electric machine serving as a traction motor for the drive wheels. This electric machine is preferably coupled to the drive wheels by a speed reducer and a differential. This coupling is preferably permanent, in the sense that it is not possible to decouple the drive wheels from the electric machine.

[0040] Conventionally, the electrical machine 10 comprises an outer casing which is made of several pieces assembled to delimit a chamber housing a rotor 20 and an annular stator.

[0041] It could be an electric machine of any type, axial or radial flux, wound rotor or not...

[0042] The stator is fixed to the housing while the rotor 20 is arranged to pivot in the stator and the housing.

[0043] The rotor 20 has a central opening through which it is fixedly mounted on a rotating shaft 21, which therefore forms the output shaft of the electrical machine 10.

[0044] Conventionally, this rotating shaft 21 is mounted in the casing so as to be able to rotate relative to it around an axis of rotation A1.

[0045] For this purpose, it is equipped, near its ends, with two bearings 30, only one of which is shown here and will be described below (the other being arranged in a standard manner in an opening in the casing).

[0046] This is a ball bearing, the inner ring of which is shrunk onto the rotating shaft 21 and the outer ring of which is placed in an opening provided for this purpose in the housing. Thus the rotating shaft 21 is guided in rotation around its axis of rotation A1.

[0047] It will be noted here that the outer ring of the bearing 30 is not directly fixed in the opening of the housing but that an intermediate piece is provided which is interposed between them. This intermediate piece, which therefore acts as an “added bearing”, will hereinafter be called annular support 110.

[0048] The rotating shaft 21 has at its free end, beyond the bearing 30 and outside the casing, a pinion 24 allowing it to be coupled to the drive wheels of the motor vehicle.

[0049] The electric machine 10 here integrates within its casing a parking brake device 100 which notably comprises this annular support 110.

[0050] According to the invention, this parking brake device 100 is multifunctional in the sense that it provides a parking brake function, but also at least one other function. The annular support 110 is then specially designed to carry the components making it possible to provide all these different functions.

[0051] A first function of the device is therefore a brake function making it possible to block any rotation of the rotating shaft 21 relative to the casing. A second of its functions is a function of grounding the rotating shaft 21. A third of its functions is a function of measuring the position and / or the angular speed of the rotating shaft 21.

[0052] If the first function is essential, it could be provided as a variant that the parking brake device 100 only provides one or the other of the second and third functions.

[0053] The components that the annular support 110 carries to ensure the first parking brake function are designed to act directly on the rotating shaft 21 of the electric machine 10 in order to brake the vehicle when the latter is parked. This rotating shaft 21 carries a toothed wheel 22 for this purpose.

[0054] In an electric or hybrid vehicle as defined above, the electric machine 10 in fact always remains coupled to the drive wheels of the vehicle since there is no clutch or gearbox provided between the electric machine 1 and the drive wheels. On the contrary, a simple speed reducer (typically single-ratio with constant mesh) is provided. Consequently, the locking of the rotating shaft 21 of the electric machine 10 makes it possible to lock the drive wheels, and therefore to ensure efficient parking braking.

[0055] In this regard, it can be noted that if a torque is exerted at the wheels, the torque felt at the rotating shaft 21 will be reduced thanks to the speed reducer, so that it will be less restrictive to brake the vehicle at the rotating shaft 21 than at the wheels.

[0056] Here, the parking brake device 100 is placed around the rotating shaft 21. The toothed wheel 22 on which it is possible to rely to mechanically perform the braking is located between the rotor 20 and the bearing 30, inside the casing. It is therefore particularly space-saving.

[0057] The annular support 110 and the components of the parking brake device 100 for performing the three aforementioned functions can now be described in more detail.

[0058] The annular support 110 is shown in detail in Figure 2.

[0059] As shown in Figure 3, it is therefore installed in an opening 12 of the casing 11, so as to be interposed between the edge of this opening 12 and the outer face of the outer ring 31 of the bearing 30. It is recalled here that the inner ring 32 of this bearing 30 is directly shrunk onto the rotating shaft 21.

[0060] The annular support 110 is a single-piece part resulting from a foundry operation. It is preferably made of gray cast iron (for example type GL04S), which gives it good lubricating, electrically conductive and damping properties, at a low cost.

[0061] It therefore forms a high stiffness interface between the bearing 30 and the casing 11, which makes it possible to reduce the noise generated by the rotation of the rotary shaft 21.

[0062] It is in fact made of a material which has a stiffness greater than that of the material of the casing 11. Furthermore, due to its presence, the opening 12 of the casing 11 has a diameter greater than that which it would have in the absence of annular support 110, so that the casing 11 itself has a stiffness greater than that which it would have in the absence of annular support 110. In this way, the rotating shaft 21 is better guided, better damped and it vibrates less, which reduces stresses and noise.

[0063] As shown in Figure 2, this annular support 110 has a first part 111 which is interposed between the bearing 30 and the casing 11, a second part 112, facing the rotor 20, on which the components ensuring the three aforementioned functions can be fixed.

[0064] The first part 111 has a ring shape, with a cylindrical internal face of revolution shrunk onto the external ring of the bearing 30, and a cylindrical external face of revolution shrunk into the opening 12. These shrink-fitting operations can be carried out under pressure.

[0065] The second part 112 forms a sort of flange extending in a plane orthogonal to this axis of rotation A1, on one side of the first part 111. It has tapped bores and wells tapped along axes parallel to the axis of rotation A1, which makes it possible to secure the components ensuring the three aforementioned functions there.

[0066] In Figure 2, the electrical conduction means 120 are also shown, which make it possible to electrically connect the rotary shaft 21 to the casing 11 so that this shaft does not become charged with electrical current and generate destructive electrical arcs in the bearing 30 or in the pinion 24.

[0067] These means are therefore designed to ground this rotating shaft 21 to electrical ground. They are also positioned as close as possible to the bearing 30 to protect it as best as possible.

[0068] They could come in various forms, typically in the form of felt incorporating metal threads.

[0069] Here it is more of a grounding ring, of the eyelash type.

[0070] It therefore comprises a ring body 121 which is designed to be locked in position on the annular support 110, and flexible electrical conduction elements 122 provided to rest on the rotating shaft 21 or, as is the case here, on an element fixed to this shaft, namely on the toothed wheel 22.

[0071] The flexible electrical conduction elements 122 are here curved metal eyelashes which extend all around the axis of rotation A1 in order to present together a good electrical conductance.

[0072] As shown in Figure 3, the ring body 121 is intended to bear directly against one side of the outer ring 31 of the bearing 30, that facing towards the inside of the housing 11.

[0073] It has an outside diameter slightly greater than or equal to the inside diameter of the annular support 110, so as to ensure electrical contact from the rotating shaft 21 to the casing 11 via this annular support 110 which, it is recalled, is made of cast iron, which gives it good electrical conduction properties.

[0074] The flexible electrical conduction elements 122 are provided projecting inside the ring body 121 in such a way that their ends extend in a circle with a diameter smaller than the diameter of the part of the toothed wheel 22 on which they rest.

[0075] Mounting this grounding ring directly on the annular support 110 reduces the risk of misalignment and therefore the risk of breakage of the eyelashes.

[0076] In Figure 3, it can be seen that a groove 124 is hollowed out in the internal face of the annular support 110, at the level of this ring 121, so as to provide a space between the ring 121 and the annular support 110 through which the oil can flow towards the bottom of the casing 11. This groove 124 therefore makes it possible to reduce the risks of bubbling of the bearing 30 and to limit the quantity of oil on the rotating shaft 21 (reducing the electrical conductivity of the latter).

[0077] In Figure 4, the means 130 for measuring the position and / or the angular speed of the rotating shaft 21 are shown.

[0078] These measuring means in practice here comprise an inductive position sensor which is adapted to determine the position of a target washer 23 fixed to the rotating shaft 21.

[0079] This target washer 23 comprises an annular body 25 which is mounted directly on the rotating shaft 21 or, as is the case here, on an element fixed to this shaft, namely on the toothed wheel 22.

[0080] It also comprises fins 26 projecting from the annular body 25 outwards, which are regularly distributed around the axis of rotation A1.

[0081] The target washer 23 is angularly indexed on the rotating shaft 21, so that the control computer of the electric machine knows its exact angular position.

[0082] The inductive position sensor comprises for its part an annular body 131 of inner and outer diameters substantially equal to those of the annular support 110. It also has three ears projecting radially outwards, which allow it to be fixed to the annular support 110, here by screwing. Three screws 132 are used here for this purpose.

[0083] Fixing this inductive position sensor directly onto the annular support 110 ensures good centering of this sensor relative to the axis of rotation A1. Thus, these measuring means 130 are suitable for determining the angular position of the rotating shaft 21 with an accuracy of the order of a tenth of a degree.

[0084] It should be noted that this sensor, once fixed, allows the earthing ring to be blocked against the bearing 30 in order to block it axially (see figure 3).

[0085] The inductive position sensor finally comprises a radial bulge 133 which projects from the annular body 131, towards the outside, and which houses data communication means connected to the control computer of the electrical machine 10. Here, this radial bulge 133 has a terminal block for this purpose allowing it to be connected by wire to the computer.

[0086] As shown in Figures 1 and 5, to achieve the desired braking, namely here a complete blocking of the rotary shaft 21 relative to the casing 11, the parking brake mechanism 140 comprises: - a means 141 for hooking the toothed wheel 22 which is fixed to the rotary shaft 21, and - an actuator 142 adapted to move the hooking means 141 between a position hooked to the toothed wheel 22 and a position unhooked from the toothed wheel 22.

[0087] As shown in Figure 4, the toothed wheel 22 comprises a tubular body 27 and, projecting from the external face of this tubular body 27, at least one relief. Here, it comprises several of them forming dogs 28. The dogs 28 have identical shapes and are regularly distributed around the periphery of the tubular body 27 of the toothed wheel 22. They thus delimit crenellations whose lateral faces extend radially relative to the axis of rotation A1.

[0088] These dogs 28 are here located mid-length of the tubular body 27 and therefore extend at a distance from the ends of this body. Thus, the tubular body 27 has a length such that it makes it possible to stiffen the rotating shaft 21 on which it is shrunk.

[0089] The target washer 23 is then mounted on the tubular body 27 of this toothed wheel 22, on the side of the bearing 30. The eyelashes of the grounding ring also rest on this side of the tubular body 27.

[0090] The hooking means 141 of the parking brake mechanism 140 could take various forms.

[0091] As shown in Figure 5, here, it is in the form of a lever 141, one end of which is shaped to engage between two dogs of the toothed wheel 22. in order to block any rotational movement of the rotary shaft 21. This end of the lever 141 carries for this purpose a tooth 141 A whose shape is identical, in negative, to the space between two dogs of the toothed wheel 22.

[0092] This lever 141 has at mid-length an opening 141 B by which it is mounted mobile in tilting on the annular support 110.

[0093] In practice, to ensure this mobility, a pin 144 is fixed on a first side to the annular support 110 and it accommodates at its opposite end the lever 141, which is mounted to rotate freely on this end of the pin 144.

[0094] This pin 144 is, preferably, substantially cylindrical of revolution around a central axis A2 parallel to the axis of rotation A1, which central axis A2 forms the articulation axis of the lever 141. It is here shrunk by its first side in a housing 114 delimited by a well which extends projecting from the second part 112 in the form of a flange of the annular support 110 (this shrunk assembly is possible since the assembly formed by the annular support 110 and the components which it supports can be assembled outside the casing 11). The opening 141 B of the lever 141 is for its part engaged on this pin 144 so that the lever 141 bears on one side against the free end of the well which accommodates the pin 144.

[0095] The lever 141 is thus mounted on the annular support 110 with a single degree of freedom, namely a pivoting mobility around an axis strictly parallel to the axis of rotation A1, between two extreme positions called hooked (in which the tooth 141 A is housed between two dogs) and unhooked (in which the tooth is located at a distance from the dogs).

[0096] Alternatively, the pin 144 could not be cylindrical of revolution or could be so only over part of its length. Typically, it could have over another part of its length a flat surface facilitating its locking in rotation on the annular support 110.

[0097] It is understood that when the lever 141 blocks the rotation of the rotary shaft 21 and the vehicle is stopped on a slope, significant forces are exerted on the pin 144.

[0098] Consequently, to prevent the latter from bending and the lever 141 from letting the toothed wheel 22 escape, means are provided for fixing the free end of this pin 144. These means are here in the form of a plate 144A pierced in its center to accommodate the free end of this pin 144 and at its ends to allow its fixing, here by means of screws 146, on the annular support 110. This plate 144A also makes it possible to block the sliding of the lever 141 along the central axis A2.

[0099] To reduce friction between this plate 144A and the lever 141 when the latter tilts, a washer can be interposed between these two elements.

[0100] The lever 141 has, at its end opposite the tooth 141A, an end support on which the actuator 142 can exert a force to cause it to tilt.

[0101] When activated, the actuator 142 is here provided to force the movement of this lever 141 towards one of the two aforementioned positions. Elastic return means 145 are provided to return it towards the other of these two positions when the actuator is inactive. These elastic return means 145 are here formed by a torsion spring threaded onto the pin 144, between the annular support 110 and the lever 141, so that one of its ends rests on the annular support 110 and another of its ends rests on the lever 141.

[0102] In practice, the actuator is intended to force the lever to swing into the hooked position.

[0103] Any type of actuator could be used, for example an electric servomotor, a moving magnet electromagnetic system, etc.

[0104] As shown in Figure 1, this actuator 142 here comprises a support 147 fixed to the casing 20 (inside the latter) and a sliding arm 148 adapted to slide relative to the support 147 towards a deployed position when it is activated, and to return to the initial position otherwise.

[0105] In the event that the rotor 20 can be controlled in angular position with great precision, the hooking of the toothed wheel 22 will be facilitated and will therefore allow the use of a reduced power actuator 142 (small and inexpensive).

[0106] In this eventuality, it could be provided that the actuator 142 is connected to the lever 141 by a simple connecting rod or that it presses directly on the lever.

[0107] However, for safety reasons, it will be preferable to provide elastic connection means 143 between the actuator 142 and the lever 141, so that if the lever 141 is blocked by the toothed wheel 22 (because its tooth is not exactly opposite a space delimited by dogs), these elastic connection means allow the actuator to slide the sliding arm 148 without damage and without forcing.

[0108] In practice, as shown in Figure 5, there is provided here at the end of the sliding arm 148 a cap 148A which is fixed to the latter and which carries, as elastic connecting means 143, a torsion spring. This cap 148A also carries a shaft 149.

[0109] This shaft 149 is mounted so as to be able to pivot in the cap 148A around the axis of the sliding arm 148. It carries a cam 149A which forms an inclined slope relative to this axis and which rests under the free end of the lever.

[0110] Thus, the sliding movement of the sliding arm 148 can force the lever to tilt, but if the latter is blocked, the shaft 149 will be able to pivot thanks to the cam 149A and avoid any damage to the mechanism. The torsion spring 143 will allow for its part of returning the shaft 149 to its initial position as soon as possible.

[0111] In Figure 1, three fixing screws 13 are illustrated, provided for fixing the annular support 110 to the casing 11 (not shown in this figure).

[0112] These fixing screws 13 conventionally comprise a head which has an imprint to facilitate its operation, and a body which is at least partly threaded.

[0113] These fixing screws 13 are intended to be engaged through holes made in the casing, from the outside thereof, in order to be screwed into the annular support 110 or into a part fixed to the latter. The annular support 110 then has for this purpose three holes, preferably passing through and parallel to the axis of rotation A1, which are possibly tapped. These three holes are here regularly distributed around the axis of rotation A1, at 120° from each other, and are made in radially projecting ears on the edge of the annular support 110.

[0114] According to the invention, as shown in Figure 6, one of these fixing screws 13 is located in such a way that it passes through the central axis A2 of the pin 144. This fixing screw 13, which will be considered in the remainder of this description, is here oriented in such a way that its screwing axis is parallel to this central axis A2. Preferably, the screwing axis of this fixing screw 13 coincides with the central axis A2 of the pin 144.

[0115] Alternatively, the fixing screw 13 could be offset from the central axis A2 by a few millimeters at most. As a further alternative, it could be inclined relative to the central axis.

[0116] In order not to block the screwing of this fixing screw 13, one of the ends of the pin 144 is then preferably hollowed out by a cavity 144B facing the free end 13B of the fixing screw 13.

[0117] Figures 6 and 7 show two variant embodiments of the fixing of the fixing screw 13.

[0118] In these figures, similar elements are referenced by the same reference signs, and only their differences will be described.

[0119] In these two embodiments, the pin 144 is therefore locked in rotation relative to the annular support 110 around the central axis A2. The lever 141 is then mounted with play on this pin so as to be able to rotate freely relative to it around the central axis A2.

[0120] In the embodiment of Figure 6, the cavity 144B formed at the end of the pin 144 has a diameter strictly greater than the diameter of the fixing screw 13 at its free end 13B. Thus the fixing screw 13 can freely rotate in this cavity.

[0121] The fixing screw 13 then passes through the hole 14 provided correspondingly in the casing 11 and is screwed into a tapped bore 110B provided in the annular support 110, in the axis of the bottom of the housing 114 receiving the pin 144. Once screwed, its head rests against the external face of the casing 11.

[0122] Thus, the forces exerted on the pin 144 are transmitted to the annular support then to the casing 11, via the fixing screw 13.

[0123] In the alternative embodiment illustrated in Figure 7 and which is preferred to the embodiment illustrated in Figure 6, the hole 110B provided in the annular support 110 is not tapped and it has a diameter slightly greater than that of the threaded body of the fixing screw 13, so that these two elements do not cooperate together.

[0124] On the other hand, the cavity 144B formed at the end of the pin 144 forms a threaded bore opening into which the fixing screw 13 is screwed. Thus, this screw makes it possible to tighten the pin 144 against the annular support 110 and the annular support 110 against the casing 11.

[0125] In this embodiment variant, there is therefore no break in rigidity between the pin 144 and the casing 11. Therefore, the aforementioned components make it possible to better resist the mechanical stresses exerted on them and they can therefore be sized accordingly so as to be less bulky and less expensive.

[0126] At this stage, it can be noted that, conventionally, a dielectric lubricant is used to lubricate the bearings 30. This lubricant will naturally lubricate the junction between the lever 141 and its pin 144, which will guarantee the parking brake device proper operation and a prolonged service life.

[0127] It will also be noted that when the vehicle is stationary on a slope and the parking brake device 100 is activated, it may prove difficult to move this device to the inactive position due to the forces exerted on it.

[0128] Consequently, to facilitate the movement of the lever, the electrical machine 10 can be controlled to rotate the rotary shaft 21 over a short stroke (of the order of 1 degree) and in a fairly short period of time during which the stresses exerted on the device will be reduced.

[0129] More generally, before each deactivation of the parking brake device 100, it will be possible to pivot the rotary shaft 21 in one direction then in the other, in order to ensure that the lever can at some point return to the released position without difficulty.

Claims

CLAIMS

1. Parking brake device (100) adapted to be installed in a casing (11) of an electric machine (10) which houses a rotating shaft (21) and at least one bearing (30) for guiding said rotating shaft (21), said parking brake device (100) comprising an annular support (110) which is adapted to be interposed between said bearing (30) and said casing (11) and which carries: - a parking brake mechanism (140) adapted to block the rotation of the rotary shaft (21) relative to the casing (11), as well as: - measuring means (130) adapted to measure the position or angular speed of the rotating shaft (21) relative to the casing (11), and / or electrical conduction means (120) adapted to conduct the electric current between the rotating shaft (21) and the casing (11).

2. Parking brake device (100) according to claim 1, wherein, the annular support (110) carrying measuring means (130) and electrical conduction means (120), said electrical conduction means (120) are adapted to be inserted between the bearing (30) and the measuring means (130).

3. A parking brake device (100) according to claim 1 or 2, wherein the parking brake mechanism (140) comprises a hooking means (141) of a toothed wheel (22) which is fixed to said rotating shaft (21), and an actuator (142) adapted to move the hooking means (141) between a position hooked to the toothed wheel (22) and a position unhooked from the toothed wheel (22).

4. Parking brake device (100) according to claims 2 and 3, wherein the electrical conduction means (120) comprise a ring (121) fixed to the annular support (110) and flexible electrical conduction elements (122) which bear on a part of the toothed wheel (22).

5. Parking brake device (100) according to one of claims 3 and 4, wherein there is provided, between the actuator (142) and the hooking means (141), an elastically deformable portion (143) adapted to allow the actuator (142) to move when the hooking means (141) is blocked by the toothed wheel (22).

6. Parking brake device (100) according to one of claims 1 to 5, wherein the measuring means (130) comprise a position sensor adapted to determine the position of a washer (23) fixed to the rotating shaft (21).

7. Parking brake device (100) according to one of claims 1 to 6, in which the annular support (110) is formed from a single piece, and is preferably made at least partly of cast iron.

8. Parking brake device (100) according to one of claims 1 to 7, in which the annular support (110) delimits an internal face of which a cylindrical part of revolution accommodates said bearing (30), and an external face of which a cylindrical part of revolution is adapted to be installed in an opening of the casing (11).

9. Electrical machine (10) comprising a casing (11), a rotor (20) housed in the casing (11), and a rotary shaft (21) which is fixed to the rotor (20) and which is pivotally mounted in the casing (11) by means of at least one bearing (30), characterized in that it further comprises a parking brake device (100) according to one of claims 1 to 8.

10. Motor vehicle comprising a chassis and wheels, characterized in that it further comprises an electric machine (10) according to claim 9, the rotary shaft (21) of which is coupled to at least part of said wheels.

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