FR3132692A1 - CLUTCH WITH MULTIPLE DEACTIVATION CONTROLS FOR STEERING-BY-WIRE SYSTEM - Google Patents

Abstract

The invention relates to a method of clutching (1) for a steering-by-wire system between a first shaft (2) and a second shaft (3) of the steering-by-wire system, said first shaft (2) and second shaft (3) having axes of rotation (6) aligned, which clutch comprises: - at least two wheels (4,5) each having an axis of rotation (6) aligned with the axes of rotation (6) of the first shaft (2) and of the second shaft (3), said at least two wheels (4, 5) each having a different driving direction of at least one other wheel; And - each of the at least two wheels (4.5) comprising at least one connection means (7) with the first shaft (2) and the second shaft (3) Abstract Figure: Fig. 3

Description

CLUTCH WITH MULTIPLE DEACTIVATION CONTROLS FOR STEERING-BY-WIRE SYSTEM

The invention relates to a clutch for securing a redundant steering-by-wire system via the use of a clutch comprising several deactivation controls, as well as to a steering-by-wire system comprising such a clutch.

In the existing steering technology known as “steer by wire”, in particular hydraulic power steering, several devices are known making it possible to restore a link between the steering wheel and the steering wheels of a moving vehicle. in the event of a steering system failure.

Thus, there is described in CN110588767A a multi-motor redundancy device and a control method for a steering-by-wire system, which can realize the overall redundancy protection in the steering system. A multi-motor redundancy device for a steering-by-wire system is thus described, characterized in that it comprises in particular a redundant motor, an input shaft, an output shaft, an intermediate shaft and a clutch. The intermediate shaft is connected to the redundant motor outside the housing via a gear structure, and is rotated by the redundant motor. A first coupler (placed upstream) moves axially relative to the intermediate shaft, and the first coupler is engaged or disengaged by a first drive device, thus connecting or disengaging the intermediate shaft and the input shaft. The lower (downstream) end of the intermediate shaft is provided with a second coupler which can move along the axial direction of the intermediate shaft, and the second coupler is engaged or disengaged from the first upper coupler by the intermediate of the intermediate shaft. Thus, the intermediate shaft can be linked or separated from the output shaft. In the event of a failure, the system disclosed in CN110588767A allows the steering to be switched to the redundant motor by actuating and disengaging the various couplers of the intermediate shaft in the clutch. A mechanical steering system placed in parallel supports this system in order to guarantee, if necessary, the driving safety of a vehicle.

The device disclosed in CN110588767A does not, however, have a double security system at the clutch level. In the event of failure, in particular of the adapter closest to the steering train, it will be the mechanical steering system optionally present which will necessarily take over.

CN111038578 discloses a dual-winding, dual-source motor-driven steering-by-wire system with two hardware redundancy functions of a motor winding. In fact, the steering column includes two worm gears separated from each other by an electromagnetic clutch. One of the worm gears (the one closest to the steering gear) is connected to a dual-winding motor module. When one winding fails, the other winding can complete the steering action under the power drive. When the power supply fails, the other power supply drives the winding to complete the steering action; When the winding and power supply fails, the steering action can still be supplemented by mechanical steering. The dual winding motor module therefore includes two complete sets of windings.

However, the dual winding motor module disclosed in CN111038578 is relatively bulky and heavy since this system includes two complete winding/power supply assemblies. In addition, this system requires double the materials to make the two complete sets of windings.

The aim of the invention is therefore to overcome the disadvantages of the prior art.

To do this, the invention thus relates, in its broadest acceptance, to a clutch for a wire steering system between a first shaft and a second shaft of the wire steering system, said first shaft and second shaft having aligned rotation axes, which clutch comprises:

- at least two wheels each having an axis of rotation aligned with the axes of rotation of the first shaft and the second shaft, said at least two wheels each having a direction of drive different from at least one other wheel; And

- each of the at least two wheels comprising at least one means of reversible connection with the first shaft and the second shaft.

Thus, the clutch according to the present invention has a double securing system thanks to the combination of at least two wheels each having a drive direction different from at least one other and each of the at least two wheels comprising at least one means of connection with the first shaft and the second shaft

Preferably, each of the at least two wheels is free and/or disengageable. Thus, advantageously in one embodiment, it is possible to engage the wheels in a complementary manner or alternatively.

Preferably, each of the at least two wheels is fixed to the first shaft or the second shaft. Thus, advantageously in one embodiment, the wheels fixed to the first shaft or to the second shaft make it possible to limit the means of reversible connections.

Preferably, the first shaft and second shaft each have an external diameter, the external diameter of the first shaft being different from the external diameter of the second shaft. Thus, these different diameters allow greater variability in possible combinations. For example, in one embodiment, it is possible to insert the reversible connection means(s) and/or the wheels are placed in the shaft having the largest diameter.

Preferably, that a portion of the first shaft is housed in a portion of the second shaft. Thus the system makes it possible to be compact, in particular when the reversible connection means(s) and/or the wheels are placed in the second shaft (having the largest diameter) which houses the first shaft.

Preferably, the at least two wheels are housed in the second shaft. This allows greater compactness of the system.

Preferably, the at least two wheels are fixed to the first shaft, which first shaft has a portion housed in the second shaft, and the at least two wheels are housed in the second shaft.

Preferably, the at least two wheels are ratchet wheels.

Preferably, the reversible connection means comprise a means for engaging the drive of each of the at least two wheels, such as a pawl or a finger, a means for actuating the engagement means, such as a system of solenoids, and a means of returning to position such as a spring.

The invention further relates to a steering-by-wire system comprising a clutch according to the clutch described above.

By “shaft”, it must be understood in the context of the present invention that it is a transmission shaft. A transmission shaft is typically a more or less thick rod, cylindrical in shape with a circular section, made of a rigid material such as a metal or an alloy of metals, such as steel or aluminum. In the context of the present invention, “the axis of rotation of a transmission shaft” is the axis of rotation at the center of the shaft section (circle) and parallel to its length.

Unlike the shaft, the axis does not transmit torque or twisting force: it only serves to guide rotation or translation.

By “at least two wheels”, it is understood in the context of the present invention that it is two or more wheels, such as two wheels, three wheels, four wheels, five wheels, six wheels, seven wheels, eight wheels, nine wheels, ten wheels, etc. Indeed, the minimum number of wheels to carry out the present invention is two, thus making it possible to have different drive directions. It is also possible to have other wheels aligned according to their axis of rotation, thus making it possible to multiply the drive means.

In the context of the present invention, the axis of rotation of a wheel is the axis passing through the center of rotation thereof (i.e. the center of the disk or of the approximate disk of the wheel) so that the wheel rolls on itself regularly (like the wheels of a car). By “approximate disc”, it is understood in the context of the present invention that the wheels can include surface irregularities (i.e. the surface is not completely smooth thus allowing particular drive of the wheel), such as wheels with ratchets, and thus the section of such wheels does not form perfect discs (the outer circle is irregular). The center of rotation is then the barycenter of the irregular circle.

Thus, by “at least two wheels with aligned axes of rotation”, it is understood in the context of the present invention that the wheels are placed one after the other along a straight line merging with each of their axes of rotation.

By “different drive directions”, it is understood in the context of the present invention that the wheels have particular patterns on their surface(s) producing increased friction and/or grip in one direction of rotation by relation to the other, that is to say when an object touches this/these surface(s).

Each of the at least two wheels comprise at least one means of connection with the transmission shafts. Indeed, the objective being to transfer the rotational torque from one of the transmission shafts to the other via at least one of the wheels in a particular scenario (e.g., stopping of operation of one of the parts of the steering system), a removable connection is therefore necessary.

Preferably, each of the at least two wheels is free. By “free” wheel, it is understood in the context of this patent application a wheel allowing a motor to drive a mechanism without being driven by it.

Preferably, each of the at least two wheels is disengageable. By “disengageable” wheel, it is understood in the context of the present invention a wheel that can be disengaged. Disengaging is the operation consisting of separating two shafts joined together by a clutch, so as to make them independent.

Conversely, “clutching” is the operation consisting of joining two shafts together by a clutch, so as to make at least one dependent on the other.

Furthermore, in a preferred embodiment, each of the at least two wheels is attached to the first shaft or the second shaft. Advantageously, the fixing of at least one wheel to the first shaft or to the second shaft is a permanent fixing thus requiring only one means of connection per permanently fixed wheel to allow connection with the other shaft.

In a particular embodiment, the end of the second shaft is adapted for fixing connection means.

For example, the outer diameter of the first shaft is different from the outer diameter of the second shaft to allow the inclusion of a cavity in the second shaft to accommodate a portion of the first shaft, possibly with at least one of the wheels.

For example, the end of the second shaft is planar (that is to say having the shape of a planar disk) or partially planar and the connection means are fixed on this plane.

Thus in a particular embodiment, at least part of the first shaft is housed in at least part of the second shaft.

Preferably, at least one wheel is housed in the second shaft.

Preferably, at least two wheels are housed in the second shaft.

In a particular embodiment, at least one of the wheels is a ratchet wheel.

A ratchet wheel is an anti-reverse device forcing a rotating mechanism to turn in only one direction.

Preferably, this wheel is provided all around its circumference with notches causing in the desired direction the lifting of a pawl to allow passage but blocked by it in the other direction.

Preferably, at least two of the wheels are ratchet wheels.

Preferably, all the wheels are ratchet wheels.

Preferably, at least two of the wheels are ratchet wheels, the anti-return directions of which are reversed.

Preferably, when the clutch according to the present invention comprises more than two wheels, the clutch may comprise at least two ratchet wheels, the anti-return directions of which are reversed.

In a particular embodiment, the connection means comprise at least one engagement means.

By “engagement means” is meant in the context of the present invention a means making it possible to engage at least one wheel. The technical effect will be when the wheel is thus engaged to engage the clutch. The engagement means can be disengaged, which will have the effect of disengaging the clutch.

Preferably, the engagement means can be a ratchet or a finger.

In particular, when the wheel is a ratchet wheel, the engagement means can be a pawl or a finger.

By “actuation means”, it is understood in the context of the present invention a means which sets in motion an engagement means, such as a pawl or a finger, so that said engagement means comes in contact with a wheel, such as a ratchet wheel, which will have the effect of engaging the wheel.

Preferably, the actuation means may comprise a back-and-forth system operable remotely, such as by a wire or by electromagnetic waves. Preferably, the back-and-forth system comprises a system of solenoids allowing, by an electrical control, to engage a movement in one direction, and a means of returning to position such as a spring, when the system of solenoids is disabled.

A solenoid system is a device that converts electrical energy into mechanical energy. It can be made up of electromagnet(s) allowing movement when supplied with electricity. It can take the form of a spool of wire in a corkscrew shape wrapped around a piston, often made of iron or other material sensitive to a magnetic field.

By a “return to position means”, it is understood in the context of the present invention a device allowing movement towards a defined region. Advantageously, this return to position means is a device requiring no power supply to allow this return to position. Preferably, the position return means is a shape memory device. Preferably, the return to position means is a spring, for example a metal spring, or an elastic material, such as an elastic polymer.

We will describe below, by way of non-limiting examples, embodiments of the present invention, with reference to the appended figures in which:

represents a cross section of a disengaged clutch according to the present invention in which one of the wheels and a reversible connection means can be distinguished;

represents a cross section of the same clutch according to the engaged figure;

represents a cross section of a clutch engaged according to the present invention in which two of the wheels and two reversible connection means can be distinguished.

represents a sectional view of a reversible connection means.

In reference to the , a first (transmission) shaft 2, placed in the central position, carries a ratchet wheel 4. The advantage of the ratchet wheel 4 is the use of a simple to implement and compact device forcing the rotary mechanism to turn in one direction only. Preferably, this ratchet wheel 4 is provided all around its circumference with notches causing a ratchet to be raised in the desired direction to allow it passage but blocked by it in the other direction. The ratchet wheel 4 thus includes a central opening allowing the first shaft 2 to pass through this wheel. The axis of rotation 6 of the first shaft 2 and the ratchet wheel 4 therefore coincide. This alignment allows the shaft to communicate its possible movement to the ratchet wheel linked to it, here. The assembly constituted by the first shaft 2 and the ratchet wheel 4 is positioned on the central axis of rotation of a second (transmission) shaft 3. Here too, the axis this alignment allows communication of a possible movement between the first shaft to the second shaft via the ratchet wheel(s). This second shaft 3 has a reversible connection means 7 which is fixed to it. The second shaft 3 can be hollow to accommodate the assembly constituted by the first shaft 2 and the ratchet wheel 4, or solid and then the assembly constituted by the first shaft 2 and the ratchet wheel 4, as well as the means of reversible connection 7 are then arranged in the elongation of the second shaft 3. The axis of rotation 6 of the first shaft 2, of the ratchet wheel 4, as well as of the second shaft 3 are combined. It can be seen on the that the reversible connection means 7 is not engaged with the wheel 4. The clutch 1 is therefore in a disengaged position as shown on the . Thus, the different diameters of the two transmission shafts 2 and 3 allowed the insertion of a reversible connection means 7 and the wheels in the shaft having the largest diameter. This compact system also presents simplicity of implementation and maintenance, given that it is essentially based on mechanical parts.

There is a representation of the clutch 1 according to the , but in its engaged configuration. Indeed, it can be seen that the reversible connection means 7 is engaged with the wheel 4. An arrow 11 indicates the direction of rotation of the first shaft 2 and therefore of the second shaft 3.

In reference to the , all the elements of Figures 1 and 2 are present (first shaft 2, second shaft 3, ratchet wheel 4, axis of rotation 6 and reversible connection means 7), but the sectional view is moved back along the axis rotation 6, revealing a second ratchet wheel 5, a second reversible connection means 7. Here, the second ratchet wheel 5 is of a smaller diameter than the first ratchet wheel 4, essentially to facilitate understanding. However, the diameter of wheel 4 and wheel 5 can be identical (or different – which could be an advantage depending on the nature of the motor used). The axis of rotation 6 of the first shaft 2, the second shaft 3, the first wheel 4 and the second wheel 5 are therefore combined. In the representation according to , the two reversible connection means 7 are engaged with the two wheels 4.5. However, advantageously in one embodiment, it is possible to engage the wheels in an alternative manner, in particular in the case where there are more than two wheels 4.5. There thus illustrates an exemplary embodiment of a clutch according to the present invention presenting a double security system thanks to the combination of at least two wheels each having a drive direction different from at least one other and each of the at least two wheels comprising at least one means of connection with the first shaft and the second shaft.

In reference to the , the reversible connection means 7 comprises in this representation two actuation means 9, which may be sets of solenoids (as shown). The reversible connection means 7 also includes a means for returning to position 10, which may be a spring (as shown). The reversible connection means 7 also comprises an engagement means 8, such as a pawl (as shown). One of the advantages of the reversible connection means 7 as illustrated in is its simplicity of implementation and whose operation relies on few electronic (and/or electrical) elements.

Claims (10)

Clutch (1) for a wire steering system between a first shaft (2) and a second shaft (3) of the wire steering system, said first shaft (2) and second shaft (3) having axes of rotation (6 ) aligned, which clutch comprises:
- at least two wheels (4,5) each having an axis of rotation (6) aligned with the axes of rotation (6) of the first shaft (2) and the second shaft (3), said at least two wheels (4, 5) each having a different driving direction of at least one other wheel; And
- each of the at least two wheels (4,5) comprising at least one reversible connection means (7) between the first shaft (2) and the second shaft (3). Clutch (1) according to claim 1, characterized in that each of the at least two wheels (4,5) is free and/or disengageable. Clutch (1) according to claim 1 or 2, characterized in that each of the at least two wheels (4,5) is fixed to the first shaft (2) or to the second shaft (3). Clutch (1) according to any one of claims 1 to 3, characterized in that the first shaft (2) and second shaft (3) each have an external diameter, the external diameter of the first shaft (2) being different from the diameter exterior of the second shaft (3). Clutch (1) according to any one of claims 1 to 4, characterized in that a portion of the first shaft (2) is housed in a portion of the second shaft (3). Clutch (1) according to any one of claims 1 to 5, characterized in that the at least two wheels (4,5) are housed in the second shaft (3). Clutch (1) according to claim 1, characterized in that:
- the at least two wheels (4,5) are fixed to the first shaft (2), which first shaft (2) has a portion housed in the second shaft (3), and
- the at least two wheels (4.5) are housed in the second shaft (3). Clutch (1) according to any one of claims 1 to 7, characterized in that the at least two wheels (4,5) are ratchet wheels. Clutch (1) according to any one of claims 1 to 7, characterized in that the reversible connection means (7) comprise an engagement means (8) of the drive of each of the at least two wheels ( 4.5), such as a pawl or a finger, an actuation means (9) of the engagement means (8), such as a system of solenoids, and a return to position means (10) such as than a spring. Steering-by-wire system comprising a clutch (1) according to any one of claims 1 to 9.