FR2890631A1 - Vehicle steering system without mechanical linkage has actuator for one wheel connected to rest of vehicle through wheel assembly alone - Google Patents

Abstract

The steering system without mechanical linkage consists of an actuator (1) for one wheel (2) that is connected to the rest of the vehicle through the wheel assembly alone. The wheel has an arm (5) and hub carrier (4), and the actuator (1) is in the form of an electric power cylinder connected to the arm via a universal joint (8) and designed to rotate the hub carrier via a ball joint (7) as it is extended and retracted.

Description

2890631 1

  FIELD OF THE INVENTION The present invention relates to a steering system for a vehicle and more particularly to a so-called by-wire steering system, or without a mechanical connection, that is to say say for which there is no mechanical connection between the steering wheel and the wheel actuator.

STATE OF THE ART

  The so-called by-wire or non-mechanical steering systems are, for example, systems for which the connection between the steering wheel and the wheel actuation device is of the wired type.

  A device for actuating the wheels generally consists of a restituteur, at least one wheel actuator, and a steering system 20 of the wheel actuator. The restituteur allows the driver of the vehicle to feel the reactions and the adhesion of his vehicle on the road. The wheel actuator makes it possible to turn the steering wheels. Finally, the steering system of the wheel actuation device manages the signals received and transmitted from both the retractor and the wheel actuator according to different steering strategies.

  Of particular interest in this invention are the wheel actuators of these wheel actuators in steering systems of by-wire type, ie type without mechanical connection.

  Among the existing steering systems, there are known by-wire steering solutions in which the wheels are connected. These solutions use for example motorized racks. Nevertheless, these solutions limit both the additional developments and the appearance of new front block architectures. Indeed, in the proposed solutions, there is always an element that passes through the front block, this element is also larger than the racks currently used in conventional directions that include a mechanical link between the steering wheel and the actuating device. wheels.

  There are also independent wheel systems controlled by two separate actuators.

  Document FR-2 812 264-A1 proposes, for example, steering systems comprising a device for actuating the wheels with an actuator provided for each steering wheel, each of the actuators being composed of a motorization device acting on a steering rod. coupled to the wheel. The motorization device can be either an electric motor or an electrohydraulic device.

  Document US-2002/0066614-A1 discloses an actuator for a by-wire type steering system. The document indeed describes an electromechanical actuator for rotating a wheel by means of a crank arm coupled to a steering lever. According to this document, the actuator is secured to the vehicle body.

  Finally, document FR-2,810,615-A1 discloses a device for actuating the wheels in a by-wire type steering system for a motor vehicle. The proposed system consists of two electrohydraulic actuators each acting on a steering wheel. The actuators are fixed on the one hand on the steering levers of the steering wheels 2890631 3 and on the other hand on the axle. In addition, a bar connects the two steering levers to ensure a degraded mode in case of failure of one of the actuators.

  An object of the present invention is to provide a by-wire type steering system comprising a simpler wheel actuator and having a less bulky arrangement.

  SUMMARY OF THE INVENTION To this end, according to the invention, there is provided a steering system of the type without mechanical connection for a vehicle comprising a wheel set, the steering system comprising a device for actuating the wheels including an actuator. a first wheel, and characterized in that the actuator is connected to the rest of the vehicle exclusively via the wheel train.

  In this, the actuator is fully integrated in said wheel train and therefore has no direct connection with the rest of the vehicle, especially with the vehicle body.

  Preferred but nonlimiting aspects of the steering system according to the invention are as follows: the wheel train comprises a first and a second part associated with the first wheel, the second part being connected to the first wheel, and the actuator extending between the first and second pieces to move the second piece relative to the first piece; the first and second parts of the wheel train are coupled together, the first part being a first arm and the second part being a hub carrier of the first wheel; The actuator comprises a jack, the jack being coupled firstly to the first arm and secondly to the hub carrier of the first wheel so that a translation movement of the jack causes a rotational movement. the hub carrier of the first wheel; the jack, which may be an electric jack, is coupled to the hub carrier of the first wheel via a ball joint and can be coupled to the first arm via a universal joint; the first arm is formed and arranged to form a first ball joint, it may for example be triangular; the first arm is located above the axis of the first wheel; the wheel train comprises a second arm coupled to the hub carrier of the first wheel, the second arm being situated below the axis of the first wheel, and arranged so as to form a second ball joint, this second arm being able to being triangular; - The wheel set comprises a second arm and a third arm arranged to form a second ball joint, the second ball joint being fictitious, and forming with the first ball joint a semi-fictive pivot assembly; - The steering system further comprises a camber control device of the first wheel being integrated in the wheel set and comprising a cylinder, said cylinder being coupled to a lifter, said lifter being further coupled to the first arm; the cylinder being coupled to the lifter can be coupled to the other side of the vehicle body or the second arm; the jack of the camber control device is arranged in such a way that a translation movement of the jack causes a transverse movement of the first arm; the wheel actuator further comprises an actuator for a second wheel independent of the actuator for the first wheel, the actuator for the second wheel being identical to the actuator for the first wheel, and arranged in the same way as the latter; - The steering system further comprises a camber driving device of the second wheel identical to the camber driving device of the first wheel, and arranged in the same manner as the latter.

  In addition, a set of wheels of a vehicle incorporating a device for actuating the wheels of a steering system according to the invention is provided.

  Finally, there is provided a vehicle comprising a steering system according to the invention.

DESCRIPTION OF THE FIGURES

  Other features and advantages of the invention will emerge from the description which follows, which is purely illustrative and not limiting and should be read with reference to the accompanying drawings, in which: - Figure 1 is a schematic representation of a system of direction of type without mechanical connection, or by-wire; Figure 2 is a perspective view of a steering system according to the invention; Figure 3 is a top view of a steering system according to the invention; FIGS. 4a to 4c illustrate the actuation kinematics of a wheel with a steering system according to the invention; FIG. 5 illustrates the rocket offset on a steering system according to the invention; FIGS. 6a and 6b illustrate the control of the camber of a wheel with a steering system according to the invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is a schematic representation of a non-mechanical or by-wire type steering system which comprises a wheel actuator.

  As described above, the wheel actuator comprises a setter, a driver, and at least one actuator.

  Interactions between the driver and the wheel actuator are via an HMI module (Human Machine Interface). Thus, the will of the driver, such as the desire to rotate his vehicle, will be transmitted to the HMI module, by means of a steering wheel for example, the HMI module then restoring the will of the driver to the actuating device wheels so that the wheels are actually turned according to the desire of the driver.

  The information from the HMI module is therefore transmitted to the control device which, according to different control strategies, will send a signal to the various actuators so that they rotate the wheels according to the will of the driver.

  At the same time that the actuators act on the wheels, the restatractor transmits a return of effort to the driver so that he can feel the reactions and adhesion of his vehicle on the road.

  It should be noted that on the wheel actuating device as illustrated in FIG. 1, each of the wheels to be rotated is provided with a separate actuator 2890631, the wheels are therefore actuated independently of one of the other.

  Figures 2 and 3 show the steering system according to the invention, respectively in a perspective view and in a view from above.

  The steering system shown in Figures 2 and 3 is of the type without mechanical connection, or by-wire, which comprises a device 10 for actuating the wheels designed to act on independent wheels.

  FIGS. 2 and 3 thus represent an actuator 1 of the device for actuating the wheels to act on a wheel 2.

  The wheel 2 is carried by a hub 3, the hub 3 being fixed to a hub carrier 4.

  The hub carrier 4 constitutes the end of a wheel train including the wheel 2. The hub carrier 4 is coupled with a first arm 5 of the wheel train. The hub carrier 4 and the first arm 5 are interconnected by a ball joint 6.

  The hub carrier 4 and the first arm 5 are furthermore coupled to the actuator 1. In fact, the actuator 1 which may be a jack, and in particular an electric jack, has an end coupled to the hub carrier 4 by the intermediate of a ball 7, while its second end is coupled to the first arm 5 via for example a universal joint 8.

  The hub carrier 4 and the first arm 5 are shaped such that, according to the arrangement described above with the actuator 1, a translational movement of the cylinder 1 causes the hub carrier 4 to rotate and thus the 2890631 8 wheel 2. The first arm 5 is an articulated arm may for example have a triangular shape.

  Figures 4a to 4c illustrate the kinematics of the wheel with this particular arrangement. It is noted that depending on the stroke of the cylinder 1, the steering of the wheel will be different. Thus, in FIG. 4a, for a stroke of the minimum cylinder 1, the wheel pivots to position itself in a first extreme position. In Figure 4b, for a stroke of intermediate cylinder 1, the wheel remains in the axis, it does not rotate. Finally, according to Figure 4c, for a maximum stroke of the cylinder 1, the wheel pivots to a second extreme position.

  According to this arrangement, the actuator 1 is totally integrated in the wheel train since the actuator 1 is interposed between the hub carrier 4 and the first arm 5.

  The integration of the actuator 1 in the wheel train notably allows a saving of space in the trunk of the engine of the vehicle.

  This type of direction can for example be integrated on a double-triangle train. In this case, the first arm 5, of triangular shape, constitutes the upper arm of the double-triangle train, that is to say the arm located above the axis 13 of the wheel 2. The first arm 5 is constituted and arranged to form a first ball 6.

  In a double-wishbone train, a second triangular shaped arm is provided. This second arm constitutes the lower arm of the double wishbone train, that is to say that it is located below the axis 13 of the wheel 2. This second arm is constituted and arranged to form a ball joint .

  The actuator 1 may also for example be integrated in a wheel train said semi-fictive pivot train as shown in Figure 5.

  In the same way as in a double-wishbone train, the first arm 5, of triangular shape, constitutes a first so-called upper ball joint, since it is placed above the axis 13 of the wheel 2.

  On the other hand, unlike the double-wishbone train, the semi-fictive pivot train comprises a third arm 10 complementary to the second arm 9, these second and third arms being both located below the axis 13 of the wheel 2. The second and third arms (9, 10) are arranged in such a way as to form a fictitious ball joint with the hub carrier 4. The ball (fictitious) is therefore offset with respect to the ball formed by the lower arm of a double-triangle train. Thus, the (imaginary) ball formed by the second and third arms (9, 10) is exteriorized.

  It is said that the fictitious lower kneecap and the upper physical kneecap form a semi- fictitious pivot hence the name of this train as a semi-fictive pivot train.

  Since the physical upper patella is relatively externalized because of the stresses resulting from the integration of the actuator 1, and the fictitious lower ball joint being exteriorized by construction, the rocket offset of this train is lower (see FIG. actuator 1 that can provide a positive or negative rocket offset. It is recalled here that the rocket offset represents the distance between the center of the wheel and the intersection between the axis of the wheel and the straight line connecting the first and the second ball joint.

  In addition, the fact of having a fully integrated actuator 1 on the wheel train, whether the latter is for example a double-wishbone train or a semi-fictional pivot train, makes it easier to control the camber of the wheelbarrow. wheel. It is recalled here that the camber corresponds to the inclination of the wheels relative to the vertical.

  Thus, the steering device type without mechanical connection, or bywire, according to the invention may also include a wheel camber control device.

  Each wheel can therefore be associated with both the actuator 1 but also with a camber control device.

  In the same way that the actuator 1 is integrated in a half wheel set, the wheel camber control device is also integrated in the same half wheel set.

  There is therefore provided a wheel camber control device which comprises a jack 11. The first end of this jack 11 is coupled directly to the vehicle body or, as in the embodiment of FIGS. 6a and 6b, to the second bar 9 of the wheel train, this coupling can be done via a pivot connection. The second end of the jack is in turn attached to a rudder 12, which rudder 12 is coupled to the first arm 5 of the wheel set.

  Unlike wheel sets in which the upper arm is fixed to the vehicle structure, the attachment of the first arm 5 is here embarked on the spreader 12, the movement of the cylinder 11 thereby controlling the camber of the wheel.

  Indeed, the arrangement of the wheel camber driving device is such that the translational movement of the cylinder 11 causes a transverse movement of the first arm 5, and therefore an inclination of the wheel relative to the vertical, as this is illustrated in Figures 6a and 6b.

  The configuration of this wheel camber control device, which is fully integrated into the wheel train at the wheel, involves additional space saving in the engine trunk in particular.

  In addition, this camber control system (cylinder 11 and lifter 12) is compact vertically. The entire system is located below the articulation between the first arm 5 and the spreader 12, which is advantageous in case of pedestrian impact.

  In addition, according to the steering system as explained above, the wheel actuating device is completely independent of the wheel camber control device. Thus, it is possible to control the wheel camber without the actuator of the wheel actuator having to operate to maintain the steering angle.

  Indeed, this system of camber variation by the cylinder 11 does not induce wheel steering variation and therefore does not require correction of this steering.

  The reader will have understood that many changes can be made without physically going out of the new lessons and advantages described here. Therefore, all modifications of this type are intended to be incorporated within the scope of the non-mechanical linkage type steering system and the wheel set as defined in the appended claims.

2890631 12

Claims (18)

  A non-mechanical linkage type steering system for a vehicle comprising a wheel set, the steering system comprising a wheel actuator including an actuator (1) of a first wheel (2), and being characterized by that the actuator (1) is connected to the rest of the vehicle exclusively via the wheel train.   2. Steering system according to claim 1, characterized in that the wheel train comprises a first and a second part associated with the first wheel (2), the second part being connected to the first wheel, and the actuator (1 ) extending between the first and second pieces to move the second piece relative to the first piece.   3. Steering system according to claim 2, characterized in that the first and second parts of the wheel train are coupled together, the first part being a first arm (5) and the second part being a hub carrier (4). of the first wheel (2).   4. Steering system according to claim 3, characterized in that the actuator (1) comprises a jack (1), the jack (1) being coupled firstly to the first arm (5) and secondly to the hub carrier (4) of the first wheel (2) so that a translation movement of the cylinder (1) causes a rotational movement of the hub carrier (4) of the first wheel (2).   5. Steering system according to claim 4, characterized in that the cylinder (1) is coupled to the hub carrier (4) of the first wheel (2) via a ball joint (7).   6. Steering system according to any one of claims 4 or 5, characterized in that the cylinder (1) is coupled to the first arm (5) via a universal joint (8).   7. Steering system according to any one of claims 4 to 6, characterized in that the cylinder (1) is an electric cylinder.   8. Steering system according to any one of the preceding claims, characterized in that the first arm (5) is formed and arranged to form a first ball joint.   2890631 13 9. Steering system according to claim 8, characterized in that the first arm (5) is located above the axis (13) of the first wheel (2).   10. Steering system according to claim 9, characterized in that the wheel train comprises a second arm coupled to the hub carrier (4) of the first wheel, the second arm being located below the axis (13). of the first wheel and arranged to form a second ball.   11. Steering system according to claim 9, characterized in that the wheel train comprises a second arm (9) and a third arm (10) arranged to form a second ball joint, the second ball joint being fictitious, and forming with the first ball joint a semi-fictional pivot assembly.   12. Steering system according to any one of claims 3 to 11, characterized in that it further comprises a camber control device of the first wheel (2), the camber control device being integrated into the train of wheels and comprising a jack (11), said jack (11) being coupled to a spreader (12), said spreader (12) being further coupled to the first arm (5).   13. Steering system according to claim 12, characterized in that the jack (11) of the camber control device is arranged in such a way that a translation movement of the jack (11) causes a transverse movement of the first arm ( 5).   14. Steering system according to any one of the preceding claims, characterized in that the wheel actuator further comprises an actuator for a second wheel independent of the actuator (1) for the first wheel (2).   15. Steering system according to claim 14, characterized in that the actuator for the second wheel is identical to the actuator (1) for the first wheel (2), and arranged in the same manner as the latter. 16. Steering system according to claim 15, characterized in that it further comprises a camber control device of the second wheel identical to the camber control device of the first wheel (2), and arranged in the same manner. than the latter.   2890631 14 A wheel set of a vehicle incorporating a steering system wheel actuator as claimed in any one of the preceding claims.   18. A vehicle comprising a steering system according to any one of claims 1 to 15.