WO2013092303A1

WO2013092303A1 - Motor-driven hub for electrically driving an axle of a hybrid-drive motor vehicle

Info

Publication number: WO2013092303A1
Application number: PCT/EP2012/075079
Authority: WO
Inventors: Daniel Walser; Gérard BAUMGARTNER
Original assignee: Compagnie Generale Des Etablissements Michelin; Michelin Recherche Et Technique S.A.
Priority date: 2011-12-20
Filing date: 2012-12-11
Publication date: 2013-06-27
Also published as: FR2984241A1; FR2984241B1; EP2794321A1

Abstract

The invention relates to a motor-driven hub for electrically driving an axle of a hybrid-drive motor vehicle, said motor-driven hub including a hub (1) that is rotatably mounted with respect to a hub holder (2) along a hub axis (A), the motor-driven hub including an electric-drive machine (4) including an internal rotor, the rotational axis (R) of which is spaced apart from the hub axis (A), the motor-driven hub including a reduction means and a coupling/uncoupling means capable of assuming a coupling position, in which the rotation of the electric machine (4) is coupled with the rotation of the hub (1), and an uncoupling position, the coupling/uncoupling means including a mechanism having a dog and sliding gear (11), the reduction means including a driveshaft (5) and a drive pinion (6) for the meshing of the hub (1) which is rotatably mounted about said driveshaft, the sliding gear (11) being permanently and rotatably secured to the driveshaft (5) and comprising a means capable of engaging, in the coupling position, with a complementary means secured to the drive pinion (6).

Description

Motorized hub for the electric drive of an axle of a hybrid traction motor vehicle

The invention relates to a motorized hub for the electric drive of an axle of a hybrid traction motor vehicle, a motorized wheel comprising such a hub and a motor vehicle comprising at least two motorized wheels.

In particular, the invention applies to motor vehicles having electrically powered wheels that can be decoupled from their electric machine when the vehicle is moved through another source of traction.

In the field of the ground connection of electric traction motor vehicles, in particular their motorized wheels, a certain number of proposals are known, including that of document WO-201 1/073320 which describes a motorized hub comprising reduction means acting between the rotor of the electric machine and the hub as well as coupling / decoupling means adapted to adopt a coupling position in which the rotation of the electric machine is coupled to the rotation of the hub and a decoupling position in which the rotation of the electric machine is decoupled from the rotation of the hub.

In the present application, the term "motorized hub" is used to designate the mechanical assembly comprising the hub, the hub-carrier, the guiding of the hub relative to the hub-carrier, the electric motor and the braking means of the hub. . The motorized hub is therefore intended on the one hand to receive a wheel equipped for example with a tire and to carry on the other hand a vehicle, generally by means of suspension means. In the present application, the term "motorized wheel" is also used to designate the mechanical assembly comprising the motorized hub defined above and the corresponding wheel.

One of the difficulties in adopting such motorized hubs on production vehicles is the compatibility with the solutions already adopted and validated by the manufacturers for certain elements such as

SUBSTITUTE SHEET (RULE 26) suspension and wheels. Another difficulty is to obtain a compact system, simple and as light as possible to make the cost acceptable for this industry. In particular, the integration of electric motors inside the wheels is particularly desirable because the adoption of electric traction often requires the need to ship batteries to store electrical energy which, even with the most powerful technologies known to date, requires to devote a sufficient volume to the batteries in the vehicle, except to greatly reduce the autonomy of an electric vehicle. Similar reasoning can be used for fuel cell or parallel hybrid vehicles.

Moreover, if we want to develop sufficient traction torque, it is necessary to install reduction means because we can not, with a sufficiently compact electric motor, develop adequate torque to ensure traction directly. of a passenger vehicle.

In addition, parallel hybrid vehicles whose thermal engine generally allows to drive at relatively high speed (for example 150 km / h) represent a particular difficulty in choosing the reduction ratio of electric traction.

Finally, it is generally necessary to integrate in the wheel, not only the electric motor, the associated necessary reduction means, but also a mechanical braking device (disk brake or friction drum).

To solve all these problems, the document WO-201 1/073320 proposes reduction means comprising two reduction stages, coupling / decoupling means comprising a clutch and sliding mechanism being used to be able to couple a ring gear with the hub. In particular, when the electric traction is decoupled, the reduction means are not rotated by the rotation of the hub when the vehicle is moved through another source of traction, to limit noise and torque induced drag.

However, when the coupling / decoupling and reduction means are arranged in a sealed casing containing a lubricant, there is the problem of good lubrication of the hub mainly by bubbling, in particular the good lubrication of the rotating joints while the vehicle is using traction thermal, especially over a long distance.

Indeed, the splash gears being interrupted, the lubrication in particular of the seal ensuring the sealing of the housing on the hub may be insufficient under certain conditions, especially when the electric traction is not used over a long distance.

In addition, the integration of the coupling / decoupling means at the gear ring which is intended to be linked to the hub is restrictive, particularly with respect to the size of said means and the significant torque they must transmit.

The invention aims to improve the prior art by providing a compact motorized hub, easy to achieve and in which the splash lubrication can be maintained when the electric traction is decoupled.

For this purpose, according to a first aspect, the invention proposes a motorized hub for the electric drive of an axle of a hybrid traction motor vehicle, said motorized hub comprising a hub for receiving a wheel, said hub being rotatably mounted. relative to a hub carrier according to a hub axis, the motorized hub comprising an electric traction machine, the electric machine comprising an outer stator connected to the hub carrier and an inner rotor whose axis of rotation is distant from the hub axis, the motorized hub including reduction means acting between the rotor of the electric machine and the hub, the motorized hub comprising coupling / decoupling means adapted to adopt a coupling position in which the rotation of the electrical machine is coupled to the rotation of the hub and a decoupling position in which the rotation of the machine electrical connection is decoupled from the rotation of the hub, the coupling / decoupling means comprising a clutch and sliding mechanism, the reduction means comprising a motor shaft intended to be connected to the rotor of the electric machine and a motor gear meshing hub which is rotatably mounted around said motor shaft, the player being constantly rotationally fixed to the drive shaft and having means adapted to cooperate, in the coupling position, with complementary means integral with the motor pinion.

According to a second aspect, the invention proposes a motorized wheel comprising such a motorized hub.

According to a third aspect, the invention proposes a motor vehicle comprising at least two motorized wheels.

Other objects and advantages of the invention will appear in the description which follows, made with reference to the appended figures, in which:

- Figure 1 is an overall perspective view of a motorized hub according to one embodiment of the invention;

- Figure 2 is a partial longitudinal sectional view of a motorized hub according to the invention.

In connection with these figures, an embodiment of a motorized hub is described below which is intended to guide and control the rotation of a wheel, in particular for the electric motorization of an axle of a traction motor vehicle. hybrid.

The motorized hub comprises a hub 1 intended to receive a wheel, said hub being rotatably mounted with respect to a hub carrier 2 along an axis of hub A. In particular, the hub carrier 2 is a rocket around which the hub 1 rotates by means of a bearing 3 hub.

The hub axis A is a constant reference in the present application, it is with respect to this axis that we refer to qualify an orientation of "radial" or "axial". As a reminder and according to the customary use in the field of the tire or the wheel, an axial orientation is an orientation parallel to the hub axis A and a radial orientation is an orientation perpendicular to the hub axis A.

The motorized hub comprises an electric traction machine 4, the electric machine 4 comprising an external stator connected to the hub carrier 2 and an inner rotor whose axis of rotation R is distant from the hub axis A. In particular, the electric machine 4 has an inner rotor whose axis of rotation R is distant from the hub axis A and parallel to said hub axis, that is to say non-coaxial.

The electric machine 4 assures the motorization and possibly the braking of the hub 1 by means of reduction means acting between the rotor of the electric machine 4 and the hub 1. The reduction means comprise a drive shaft 5 intended to be connected to the rotor of the electric machine 4 and a drive gear 6 meshing the hub 1, said motor pinion being mounted in rotation about said drive shaft. In addition, the reduction means comprise a ring gear 7 rotatably connected to the hub 1 and to the driving pinion 6.

The reduction means preferably comprise two reduction stages. In FIG. 2, a first reduction stage comprises the gear of the driving pinion 6 and a gear 8 connected to an intermediate shaft 9 parallel to the hub axle A, a second reduction stage comprising the gearing gear a reduction gear 10 connected to the intermediate shaft 9 and to the ring gear 7 connected to the hub 1. The overall reduction ratio is preferably greater than 15. The motorized hub comprises coupling / decoupling means capable of adopting a coupling position in which the rotation of the electric machine 4 is coupled to the rotation of the hub 1 and a decoupling position (FIG. 2) in which the rotation of the machine 4 is decoupled from the rotation of the hub 1, so as respectively to establish and interrupt the transmission of torque between the reduction means and the hub 1.

The coupling / decoupling means comprise a clutch and sliding mechanism January 1, said player being constantly rotatably connected to the drive shaft 5 and having means adapted to cooperate, in the coupling position, with additional means integral with the drive pinion 6 to drive said drive pinion and thus the hub 1 in rotation through the electric machine 4.

In the embodiment shown, the player 1 1 is mounted in translation around the drive shaft 5 between a coupling position and a decoupling position. In known manner, a fork 12 is engaged in a groove 13 of the player 1 1 to control its axial position, said fork can be controlled by a screw actuator and nut comprising a small electric gear motor or an electromagnet.

To ensure the rotation of the player 1 1 about rotation around the drive shaft 5, said player has cylindrical inner grooves 14 and the drive shaft 5 has cylindrical outer splines 15 adapted to cooperate with said inner splines on the race of translation of said player.

The driving pinion 6 comprises cylindrical outer splines 16 adapted to cooperate, in the coupling position, with the cylindrical inner splines 14 of the player 11. In particular, the splines 16 axially extend the splines 15, the player 1 1 being pushed in axial overlap around the driving pinion 6 to ensure the coupling. The entire transmission, that is to say the set of reduction means and coupling / decoupling means, is contained in a sealed casing 17 containing a suitable quantity of a lubricant in order to lubricate the assembly by bubbling. . Advantageously, when the vehicle rolls in decoupled mode and the electric machine 4 is stopped, the reduction means are rotated by the hub 1 so as to maintain the lubrication by bubbling. The stator of the electrical machine 4 is rotatably connected to the hub carrier 2. This connection, necessary for the transmission of the torque, can be rigid and direct but it can preferably be indirect in order to allow a relative rotational movement at the same time. opportunity of suspension travel. This relative movement is of course limited and aims to allow a certain independence between the transmitted torque and the dynamic rigidities (vertical and horizontal) of the suspension device.

In particular, the stator of the electric machine 4 is carried by the housing 17 while said housing is rotatably mounted relative to the hub carrier 2 according to the hub axis A. The rotation of the housing 17 relative to the hub carrier 2 can be controlled by a connecting rod acting between the housing 17 and the vehicle body.

In addition, the motorized hub comprises a disc brake whose disc 18 is placed outside the housing 17 relative to the vehicle. Although this is a preferred embodiment, it is known to those skilled in the art that in some situations it may be preferable to use a drum brake instead of the disc brake.

An advantageous way of constructing a hybrid vehicle is to combine a conventional thermal engine of the front axle and an electric motorization of the wheels of the rear axle according to the invention. In particular, the hub carriers 2 of the wheels can each be secured to an arm pulled from the rear axle, for example torsionally, of the hybrid vehicle. The electric power source may be a set of batteries or supercapacitors, a fuel cell, an urban network in the manner of trolley buses or any other available electrical source.

Whatever the embodiment of the invention, the reduction means are preferably reversible to allow the use of the electric machine 4 in braking mode. The electrical energy recovered by the electric machine 4 in braking mode can be stored or dissipated in a manner known per se.

A motorized hub according to the invention thus allows coupling / uncoupling the electric motor at any time, including during the movement of the vehicle. To allow decoupling smoothly, it is preferable to control the electric machine 4 so that it transmits a zero or very low torque at the time of the movement of the player 1 1.

Although the present description focuses on a specific embodiment, those skilled in the art can consider other combinations of the various means described herein or other combinations of some of these means with other means not described here but known. of the state of the art.

Claims

1. Motorized hub for the electric motorization of an axle of a hybrid traction motor vehicle, said motorized hub comprising a hub (1) intended to receive a wheel, said hub being rotatably mounted with respect to a hub carrier (2) according to a hub axle (A), the motorized hub comprising an electric traction machine (4), the electric machine (4) comprising an outer stator connected to the hub-carrier (2) and an inner rotor whose axis of rotation ( R) is remote from the hub axle (A), the motorized hub comprises reduction means acting between the rotor of the electric machine (4) and the hub (1), the motorized hub comprising coupling / decoupling means adapted to adopt a coupling position in which the rotation of the electric machine (4) is coupled to the rotation of the hub (1) and a decoupling position in which the rotation of the electric machine (4) is decoupled from the rotation of the hub (1), coupling means e / decoupling comprising a clutch mechanism and sliding (1 1), the reduction means comprising a drive shaft (5) intended to be connected to the rotor of the electric machine (4) and a driving pinion (6) meshing of hub (1), said motorized hub being characterized in that the driving pinion (6) is rotatably mounted around the driving shaft (5), the sliding member (1 1) being constantly rotatably connected to the driving shaft ( 5) and comprising means capable of cooperating, in the coupling position, with complementary means integral with the driving pinion (6).

2. Motorized hub according to claim 1, characterized in that the player (1 1) is mounted in translation around the drive shaft (5) between a coupling position and a decoupling position.

3. Motorized hub according to claim 2, characterized in that the player (1 1) comprises cylindrical inner splines (14), the drive shaft (5) having cylindrical outer splines (15) for rotationally fastening said player with said motor shaft.

4. Motorized hub according to claim 3, characterized in that the motor pinion (6) has cylindrical outer splines (16) adapted to cooperate, in the coupling position, with the cylindrical inner grooves (14) of the player (1 1). .

5. Motorized hub according to any one of claims 1 to 4, characterized in that the reduction means comprise a ring gear (7) rotatably connected to the hub (1) and the motor pinion (6).

6. Motorized hub according to claim 5, characterized in that the reduction means comprise two reduction stages.

Motorized hub according to Claim 6, characterized in that a first reduction stage comprises the gear of the driving pinion (6) and a toothed gear (8) connected to an intermediate shaft (9), a second stage reduction device comprising the gear of a reduction gear (10) connected to the intermediate shaft (9) and of the ring gear (7) connected to the hub (1).

Motorized hub according to any one of claims 1 to 7, characterized in that it comprises a sealed housing (17) containing the reduction means and the coupling / decoupling means and carrying the electrical machine (4), said housing containing a lubricant.

Motorized wheel comprising a motorized hub according to any one of claims 1 to 8.

Motor vehicle comprising at least two motorized wheels according to claim 9.

1 1. Motor vehicle according to claim 10, characterized in that two motorized wheels are arranged on the rear axle of said vehicle, the carriers hubs (2) of said wheels each being integral with an arm pulled from the rear axle.