Device for motorizing a motor vehicle wheel.

Abstract

Device for motorizing a wheel of a motor vehicle 1 comprising a conventional half-train 10 consisting of: a wheel hub 11; a wheel bearing 12; a steering knuckle 13; a constant velocity joint 14 for transmission, receiving the power from the powertrain 100 by the transmission shaft 14a and transmitting it to the hub 11 by its splined knuckle 14b; a brake disc 16 and a rim 17 fixed together to the wheel hub 11 by the screws 18; a tire 19; a strut 20 fixed in the upper zone of the steering knuckle 13 and on which the structure of the vehicle rests; a ball joint 21 fixed in the lower zone of the steering knuckle 13 provided with a movable arm 22 linked to the suspension triangle 23 at the annular ends 23a containing a filter block 24, the arm being movable around of the pivot axis 25 held by the guide support 60a attached to the cradle 60;and comprising an electric powertrain 100 consisting of a motor 110, a planetary gear reducer 120 driving the wheel via the transmission shaft 14a equipped with a ball slide, characterized in that the powertrain 100 is suspended from the side member 50 and pivots along the YY axis allowing its rotation axis 101 and the transmission shaft 14a to remain aligned regardless of the movement of the half-train. Figure for the abstract: Fig.1;

Description

Title of the invention: Device for motorizing a motor vehicle wheel. TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to an electric propulsion device for an automobile.

[0002] more precisely, it deals with a powertrain associated with each wheel while being close to it without being integrated therein because it is carried by the chassis of the vehicle. STATE OF THE ART

[0003] In the evolution of the automobile towards electric traction, we know the extremely widespread architecture taking up that of vehicles with thermal engines. The engine is rather centered between the wheels, associated with a reducer very generally with a single ratio, of the offset differential type or of the coaxial type, and connected to the wheels by two conventional transmission shafts with homokinetic joints. These powertrains, compact compared to thermal engine groups, are arranged at the front, at the rear or both.

[0004] One solution to save space for a larger and more capacious battery is to arrange the motorization in the wheels. Publications US3812928, FR2726230, FR2981013 show that research relating to this architecture dates back well before the appearance of modern electric cars of the twenty-first century. The wheel is mounted on the motor and reducer assembly. The additional, unsprung mass significantly modifies the sprung to unsprung mass ratio. This ratio significantly influences the vehicle's suspension, actually degrading the comfort and handling of the vehicle. In addition, the powertrain no longer benefits from the vibration filtering of the suspension, which is detrimental to its durability.

[0005] Another approach is described in a series of recent publications US11571966B1, US11639101B1, US2023020023A1, US2023311645Al, US2023311646A1 in which the motor is carried by the frame and the reducer by the wheel. According to the illustrations, they are all based on the same fundamentals: • The motor is fixed on the frame in an apparently rigid manner; • A rigid transmission shaft connects the motor to the wheel and ends with a toothing acting as a sun gear in an epicyclic gear train; • No connecting member giving a degree of freedom between the teeth at the end and the rotor is visible. However, the distance between the motor and the wheel is not invariable in all circumstances; • the sun gear drives the crown wheel by a succession of four pinions belonging to two, three or four branches. This gives freedom of movement of the crown wheel linked to the wheel, and therefore of the wheel, relative to the sun gear and the motor, in the vertical and horizontal directions; • the concept disclosed in these publications does not seem suitable for steered wheel trains, because there is no articulation (homokinetic tripod joint) between the sun gear and the transmission shaft; • it is not shown how the braking device is integrated; • the reducer with its cascade of pinions (five tooth contacts between the planetary and crown) certainly penalizes mechanical efficiency. PRESENTATION OF THE INVENTION

[0006] the object of this invention is the electric motorization of a wheel, the particularity of which is that the entire powertrain is close to but not carried by it.

[0007] The main goal is to motorize trains with or without steerable wheels with a minimum of modification. For a front half-train, there is no real difference since it is limited to the transmission shaft going from the constant velocity joint to the powertrain.

[0008] The powertrain is carried by the chassis. The valuable advantage is that it then has no influence on the unsprung mass, on the suspension setting, on the comfort and behavior of the vehicle.

[0009] The powertrain is compact thanks to its magnet rotor and its flat epicyclic gear reducer.

[0010] It is suspended from the side member by means of two vertical arms each having, at the base, a suspension stud crossed by a horizontal half-axis creating a single axis intersecting with the axis of rotation of the powertrain and perpendicular to it. The powertrain can pivot along this axis and follow the vertical movements of the wheel.

[0011] Since the train does not have infinite stiffness, the wheel can have relative movements, other than vertical, during stresses such as: • braking, acceleration, curb mounting, speed bumping which can cause relative movement of the wheel in relation to the chassis in the longitudinal direction of the vehicle; • turns, side impacts on a curb, in a pothole, can cause a relative displacement of the wheel in relation to the chassis in the transverse direction of the vehicle.

[0012] Therefore, the powertrain suspension must have flexibility relative in order to limit, to a low level, the constraints in the transmission shaft and the reducer.

[0013] Thus, between the pivot axes linked to the engine casing and the chassis are interposed suspension pads made of stiff elastomer in the vertical direction (recovery of the engine torque) and flexible in the horizontal direction so that the engine can also pivot slightly and easily along a vertical axis.

[0014] The suspension pads are secured to flat sheet metal supports, stiff in the vertical direction (torque absorption), stiff in the transverse direction of the vehicle (flexibility provided by the elastomer pads) and flexible in the longitudinal direction of the vehicle.

[0015] during vertical movements of the wheel, the distance between the articulation point of the constant velocity joint and the pivot axis of the powertrain changes. For complete decoupling, a ball slide is interposed between the sleeve of the satellite carrier from which the movement and torque of the reducer come out and the grooved sleeve which receives the end of the transmission shaft of the constant velocity joint. DETAILED DESCRIPTION OF THE INVENTION

[0016] These characteristics, aims and advantages of the present invention will appear on reading the detailed description which follows and with regard to the appended drawings given as non-limiting examples and in which:

[0017] [Fig. l]is the sectional presentation of the half-train and its powertrain, vehicle stationary or moving, in the average load state.

[0018] [Fig.2]is a sectional view of the powertrain

[0019] [Fig.3]is the description of the cooling and lubrication network of the powertrain.

[0020] [Fig.4]is the description of the suspension of the powertrain

[0021] [Fig.5]is the comparison of the half-train between the situations of normal stress and vertical compression.

[0022] [Fig.6]is the comparison of the half-train between the situations of normal stress and vertical relaxation.

[0023] [Fig. l] shows in section the half-axle, the powertrain and the chassis elements to which they are attached.

[0024] The half-axle 10 shown in [Fig.l] is a classic Macpherson type. It consists of the hub 11 of the wheel bearing 12, the steering knuckle 13, the constant velocity joint 14. The transmission shaft 14a, linked to the power unit 100 transmits the power to the constant velocity joint 14. The knuckle 14b is splined and drives the hub 11 in rotation. Its threaded end receives the nut 15 which secures all of these components. The transmission shaft 14a and the knuckle 14b have a point of articulation 14c.

[0025] The brake disc 16 and the rim 17 are attached to the hub 11, held together by the wheel screws 18. A tire 19 is mounted on the rim.

[0026] The steering knuckle 13 is the connecting element of the wheel assembly with the structure of the vehicle.

[0027] In the upper zone is fixed the strut 20, the upper part of which (not shown) comprises the suspension spring, the shock absorber, a ball bearing if it is a steered wheel, an end-of-travel shock absorber and a branch for attaching the steering rod. The structure of the vehicle rests on this strut.

[0028] In the lower zone of the stub axle 13, a ball joint 21 is attached. Its movable arm 22 is connected to the suspension triangle 23, with two branches, the annular ends 23a of which contain an adhered filter block 24, crossed by the pivot axis 25. This axis is attached to the cradle 60, by the guide support 60a.

[0029] The homokinetic joint 14 provides the connection between the half-axle 10 and the powertrain 100. The latter is suspended from the side member 50 by means of two support arms 51 provided with a filter block 52.

[0030] the power unit 100 shown in [Fig.2] comprises a synchronous or asynchronous electric motor 110 and a reducer 120 with epicyclic gear train.

[0031] The casing 111 and the cover 112 form the engine compartment housing a stator 113, a rotor 114 carried by two ball bearings 115 and a resolver 116 to control it in speed.

[0032] At the end of the rotor shaft is cut the toothing 114a which constitutes the sun gear of the epicyclic gear train of the reducer 120.

[0033] the reducer contained in the compartment formed by the casing 111 and the cover 121 is made up of a crown 122 mounted fixedly, for example hooping plus axial inlay in the casing 111, of a planet carrier comprising a main body 123 and a reinforcing sheet 123a carrying the axes 124 of the satellites 125.

[0034] The bearing 126 guides the sleeve 123b, central hub of the main body 123, in the cover 121.

[0035] the sealing of the reducer is ensured by the dynamic seal 127 between the cover 121 and the sleeve 123b and by the cover 128 obstructing the main body 123.

[0036] In the sleeve 123b are cut the outer tracks 123c of the ball slide 130. The inner tracks of the slide are cut in the grooved sleeve 131. At its end a groove retains an extensible stop ring 132 for securing with the transmission shaft.

[0037] A bellows 133 carried by the end of the sleeve 123b will close the compartment of the ball slide 130, lubricated by grease, after installation of the transmission shaft.

[0038] Outside the engine casing 111, precisely at the height of the single rotation axis 101 of the power unit 100, and approximately between the rotor 114 and the reducer 120, two aligned bosses 111a are located forming an axis perpendicular to the rotation axis 101. These bosses each have a blind recess 111b in which a self-lubricated ring 117 is fitted.

[0039] [Fig.3] describes the common device for cooling the motor 110 and lubricating the reducer 120.

[0040] The fluid, acting as lubricant, is oil. This comes from an external network (not shown) to the powertrain via a single inlet 150 in the cover 112. The internal circuit begins with the cannula 151 carried by the cover 112 and the casing 111. It passes longitudinally through the internal space of the engine and is positioned at the top of this space. The downwardly oriented holes 151a water the sheet metal pack and the coils of the stator winding 113. This cannula 151 is the only cooling device for the engine 110.

[0041] In the extension of the cannula 151, the bore 152 in the casing 111 feeds another bore 153 in the cover 121 which discharges the oil into the compartment of the reducer 120.

[0042] At a certain height, an opening 154 in the casing canvas 111 evacuates the excess oil towards the engine compartment along the path 156. When stopped, a residual amount of oil in the reducer compartment determines the level 155. The lubrication of the reducer components is entirely carried out by splashing.

[0043] The fluid is discharged to the external network through the single outlet 157 located at the bottom of the cover 112.

[0044] [Fig.4]describes the suspension device of the powertrain. On the right we have the view of the engine from the cover side 112 and on the left a section AA of the suspension under the side member 50.

[0045] On either side of the engine casing 111 in the horizontal axis YY transverse to the powertrain, but corresponding to the longitudinal direction of the vehicle, and at the altitude of the single rotation axis 101, we have the suspension bosses 111a, with a blind centered recess 111b in which a self-lubricated ring 117 is fitted. The axis YY is for the powertrain that of its pivoting.

[0046] The power unit is suspended by two support arms 51 made of sheet metal. Close to the lower part of these arms are the filter blocks 52. Each block is composed of an outer ring 53 connected to the support arm 51, for example by a weld bead, an inner ring 54 with central thread; the two rings being connected by an adhered elastomer 55.

[0047] The space between the rings 53,54 is completely filled by the elastomer 55 in the vertical axis ZZ. The support must be stiff and strong in this direction because it opposes the torque coming out of the reducer.

[0048] The space between the rings 53, 54 has two recesses 55a in the horizontal axis XX in order to provide a certain flexibility, the purpose of which is to reduce the stresses in the transmission shaft, the ball slide and the planet carrier in response to the stresses coming from the wheel during movement of the train in the longitudinal direction of the vehicle.

[0049] In addition to this flexibility of the filter blocks 52, there is that of the support arms 51 in the direction of the YY axis. These arms must, however, be very stiff in the direction of the ZZ axis.

[0050] The suspension of the powertrain is finalized by the screws 56 locked in the internal thread 54a of the ring 54. The cylindrical end 56a of the screw 56 penetrates into the bosses 11a and is adjusted to the ring 117. This assembly creates neither clamping of the powertrain between the support arms 51 nor friction opposing the pivoting.

[0051] [Fig.5] shows the half-train 10 in 2 different situations: on the left, without any particular stress on the suspension, and on the right with a stress causing its vertical compression 200 of height +H. The axis of rotation 101 of the power unit 100 defined by the straight line passing through the articulation point 14c of the homokinetic joint 14 and by the intersection with the pivot axis YY of the power unit makes an angle Al with the wheel axis. The distance between these two points becomes DI which justifies the presence of the ball slide.

[0052] [Fig.6] shows the half-train 10 in 2 different situations: on the left, without any particular stress on the suspension, and on the right with a stress causing its vertical relaxation 210 of height -H. The axis of rotation 101 of the power unit 100 defined by the straight line passing through the articulation point 14c of the homokinetic joint 14 and by the intersection with the pivot axis YY of the power unit makes an angle A2 with the wheel axis. The distance between these two points becomes D2 which justifies the presence of the ball slide.

Claims

Claims

1. Device for motorizing a motor vehicle wheel (1) comprising a conventional half-train (10) consisting of: • a wheel hub (11); • a wheel bearing (12); • a steering knuckle (13); • a constant velocity joint (14) for transmission, receiving the power from the powertrain (100) by the transmission shaft (14a) and transmitting it to the hub (11) by its splined knuckle (14b); • a brake disc (16) and a rim (17) fixed together to the wheel hub (11) by the screws (18); • a tire (19); • a strut (20) fixed in the upper zone of the steering knuckle (13) and on which the structure of the vehicle rests;• a ball joint (21) fixed in the lower zone of the stub axle (13) provided with a movable arm (22) linked to the suspension triangle (23) at the annular ends (23a) containing a filter block (24), the arm being movable around the pivot axis (25) held by the guide support (60a) attached to the cradle (60); and comprising an electric powertrain (100) consisting of a motor (110), a reducer (120) with a planetary gear driving the wheel via the transmission shaft (14a) equipped with a ball slide (130), characterized in that the powertrain (100) is suspended from the side member (50) and pivots along the YY axis allowing its rotation axis (101) and the transmission shaft (14a) to remain aligned regardless of the movement of the half-gear.;

2. Device for motorizing a motor vehicle wheel (1) according to claim 1 characterized in that the suspension on the side member (50) of the powertrain (100) consists of two support arms (51) arranged on either side of the engine (110), each having in the lower part a filter block (52). Each block is composed of an outer ring (53) linked to the support arm (51), for example by a weld bead, an inner ring (54), internally threaded and the two rings are secured by an adhered elastomer 55.

3. Device for motorizing a motor vehicle wheel (1) according to claim 1 or 2 characterized in that the space between the rings (53,54) is entirely filled by the elastomer (55) along the vertical axis ZZ. In this direction, the support must be stiff and resistant to take up the torque coming from the reducer. The space between the rings (53,54) has two recesses (55a) along the horizontal axis XX in order to provide a certain flexibility, the purpose of which is to reduce the stresses in the transmission shaft, the ball slide and the planet carrier in response to the stresses coming from the wheel during movement of the train in the longitudinal direction of the vehicle.

4. Device for motorizing a motor vehicle wheel (1) according to claim 1 characterized in that on either side of the engine casing (111) in the horizontal YY axis and transverse to the powertrain, corresponding to the longitudinal direction of the vehicle, and at the altitude of its single axis of rotation (101), we have the suspension bosses (11 la), with a blind recess (111b) in which a self-lubricated ring (11 le) is fitted. The YY axis is for the powertrain that of its pivoting.

5. Device for motorizing a motor vehicle wheel (1) according to one of the preceding claims, characterized in that the suspension of the powertrain is finalized by the screws (56) locked in the internal thread (54a) of the ring (54) and the cylindrical end (56a) of which penetrates into the bosses (111a) and is adjusted to the ring (117).

6. Device for motorizing a motor vehicle wheel (1) according to claim 1 characterized in that when the half-train (10) undergoes, during a stress coming from the ground, a vertical displacement (+H -H), the axis of rotation (101) of the powertrain makes an angle (A1, A2) relative to the axis of rotation of the constant velocity joint (14) and the distance between the articulation point (14c) of the constant velocity joint (14) and the pivot axis (YY) of the powertrain changes from (D) to (D1, D2) justifying the need for a transmission shaft made telescopic by the presence of the ball slide (130) connecting the transmission shaft (14a) with the sleeve (123b) of the planet carrier.

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